U.S. Department of the Interior

Bureau of Land Management

El Centro Field Office

1661 South 4th St

El Centro, CA 92243

May 2003

Final Environmental Impact

Statement for the

Imperial Sand Dunes Recreation

Area Management Plan

and

Proposed Amendment to the

California Desert Conservation Plan

1980
BLM/CA/ES-2003-017 + 1790 - 1600

Cover Sheet

Imperial Sand Dunes Recreation Area Management Plan

Final Environmental Impact Statement and Plan Amendment

Agency: U.S. Department of the Interior

Bureau of Land Management

California Desert District

El Centro Field Office

Project Location: Imperial Sand Dunes Recreation Area

Imperial County, California

For Further Information Contact: Ms. Lynnette Elser

Bureau of Land Management

El Centro Field Office

1661 South Fourth Street

El Centro, CA 92243

Abstract: The document is an Environmental Impact Statement 

for a proposed Recreation Area Management Plan 

(RAMP) and plan amendment to the 1980 California 

Desert Conservation Area Plan. The RAMP provides a 

process to balance recreational use of the ISDRA with 

conservation of natural resources.

This document was produced through a coordinated 

process involving numerous local, state, and federal 

agencies, special interest groups and private citizens.
Table of Contents

EXECUTIVE SUMMARY.................................................................................................1

BACKGROUND....................................................................................................................1

ALTERNATIVES ..................................................................................................................3

CHAPTER 1: INTRODUCTION AND BACKGROUND ................................................9

INTRODUCTION ..................................................................................................................9

PURPOSE AND NEED.........................................................................................................10

ISDRA OVERVIEW...........................................................................................................13

RELATIONSHIP TO POLICIES, PLANS, AND PROGRAMS.......................................................19

PLANNING ISSUES ............................................................................................................27

Issues, Concerns, and Opportunitie s ........................................................................27

Desired Future Conditions And Management Goals .................................................33

AUTHORIZING ACTIONS....................................................................................................33

CHAPTER 2: ALTERNATIVES FOR ISDRA MANAGEMENT.................................37

INTRODUCTION ................................................................................................................37

ALTERNATIVES ANALYZED IN THE EIS ............................................................................40

Alternative 1: No Action Alternative .......................................................................41

Actions Common to the Action Alternatives (Alternatives 2 -4)................................47

Alternative 2: Recreation and Natural/Cultural Resource Protection Alternative .....50

Alternative 3: Natural and Cultural Resources Protection Alternative .....................59

Alternative 4: Motorized Recreation Opportunities Alternative ...............................67

ALTERNATIVES CONSIDERED BUT ELIMINATED ................................................................75

Hybrid Recreation Intensive Alternative ..................................................................75

Total Closure Alternative .........................................................................................75

Interim Management Alternative .............................................................................76

CHAPTER 3: AFFECTED ENVIRONMENT ................................................................81

INTRODUCTION ................................................................................................................81

3.1 RECREATIONAL RESOURCES .......................................................................................83

3.2 BIOLOGICAL RESOURCES ...........................................................................................96

3.3 LAW ENFORCEMENT AND PUBLIC SAFETY ................................................................142

3.4 SOCIAL.....................................................................................................................145

3.5 ECONOMIC ...............................................................................................................155

3.6 LAND USE AND LAND OWNERSHIP ...........................................................................159

3.7 VISUAL RESOURCES .................................................................................................178

3.8 WATER RESOURCES.................................................................................................186

3.9 CULTURAL RESOURCES............................................................................................189

3.10 TRANSPORTATION AND TRAFFIC.............................................................................193

3.11 NOISE....................................................................................................................202

3.12 AIR QUALITY.........................................................................................................205

3.13 HAZARDOUS MATERIALS........................................................................................215

3.14 GEOLOGY, ENERGY, AND MINERAL RESOURCES......................................................223
CHAPTER 4: ENVIRONMENTAL CONSEQUENCES..............................................231

4.1 RECREATION RESOURCES .........................................................................................232

4.2 BIOLOGICAL RESOURCES..........................................................................................250

4.3 LAW ENFORCEMENT AND PUBLIC SAFETY.................................................................261

4.4 SOCIAL....................................................................................................................264

4.5 ECONOMIC ...............................................................................................................269

4.6 LAND USE AND LAND OWNERSHIP ...........................................................................302

4.7 VISUAL RESOURCES .................................................................................................309

4.8 WATER RESOURCES..................................................................................................316

4.9 CULTURAL RESOURCES............................................................................................320

4.10 TRANSPORTATION AND TRAFFIC.............................................................................323

4.11 NOISE.....................................................................................................................327

4.12 AIR QUALITY .........................................................................................................332

4.13 HAZARDOUS MATERIALS........................................................................................349

4.14 GEOLOGY AND SOILS .............................................................................................351

CHAPTER 5: COORDINATION & CONSULTATION..............................................357

Public Scoping Meetings .......................................................................................357

U. S. Fish & Wildlife Service Consultation............................................................359

Consultation with the State Historic Preservation Officer.......................................359

Consultation with Native Americans......................................................................359

Other Consultations...............................................................................................360

Coordination of Comments on the draft EIS ..........................................................360

CHAPTER 6: LIST OF PREPARERS ..........................................................................361

CHPATER 7: REFERENCES........................................................................................367

CHAPTER 8: GLOSSARY AND LIST OF ACRONYMS ...........................................379

APPENDIX A: PUBLIC COMMENTS AND RESPONSES SUMMARY

APPENDIX B: MONITORING REPORT

APPENDIX C: EMISSION CALCULATION METHODOLOGY
1

EXECUTIVE SUMMARY

The Bureau of Land Management (BLM) has prepared this Environmental Impact Statement 

(EIS) to analyze the potential environmental impacts from the revision and updating of the 

1987 Recreation Area Management Plan and Environmental Assessment for the Imperial 

Sand Dunes. A revised Recreation Area Management Plan (RAMP) will provide direction 

and guidance on the management of land use and resources in the Imperial Sand Dunes 

Recreation Area (ISDRA) that would be consistent with public needs and resource status. 

Implementing a revised RAMP would also constitute a Plan Amendment to the California 

Desert Conservation Area (CDCA) Plan, in accordance with BLM planning regulations (43 

CFR 1610.3-2) 

Background

The Imperial Sand Dunes Recreation Area (ISDRA) is the most popular Off Highway 

Vehicle (OHV) area in the southwest United States. It encompasses the most intensively 

visited recreational area in the CDCA. It provides a unique, world-class recreation 

opportunity. The primary recreational use is camping and the use of OHVs, principally dune 

buggies and all terrain vehicles. Other uses include photography, hiking, backpacking, 

nature studies, walking, hunting, rock collecting, right of way use for utility lines, canals and 

roads, filming, conservation activities and horseback riding.

 

Goals

The ISDRA will be managed to achieve the following guiding goals:

- Goal 1 - Provide a variety of sustainable OHV and other recreational activities.

- Goal 2 - Maintain or improve conditions of the special status species and other unique

natural and cultural resources.

- Goal 3 - Create an environment to promote the health and safety of visitors, 

employees, and nearby residents by working with local, state, and federal agencies 

and interest groups.

The management of the ISDRA would be multi-faceted. It would increase the effectiveness 

of law enforcement, provide sustainable recreational opportunities, and conserve natural and 

cultural resources.

Approach

The three action alternatives evaluated in the EIS propose managing the ISDRA based on 8 

individual management areas. The eight individual management units are: 
2

- Mammoth Wash Management Area 

- North Algodones Dunes Wilderness Management Area 

- Gecko Management Area 

- Glamis Management Area 

- Adaptive Management Area 

- Ogilby Management 

- Dune Buggy Flats Management 

- Buttercup Management Area 

Each management area would offer specific recreational opportunities based on the 

Recreation Opportunity Spectrum (ROS) classification system. The ROS system determines 

the visitor supply and types of available services based on a desired recreational opportunity. 

The recreational opportunity classification for each management area would determine the 

types of recreation, level of development and types of services that would be available in that 

management area. 

Challenges

The continued popularity of the ISDRA has resulted in a large increase in visitors. In 

addition, part of the ISDRA was designated as Wilderness, reducing the available land for 

OHV recreational use. Also, the ISDRA is home to several sensitive species. The 

management challenge of balancing the increasing demand for OHV recreation and 

conservation of special status species was addressed through the development of an Adaptive 

Management Area. One of the major challenges in developing a management plan is 

integrating sustainable habitat and recreational use for the Adaptive Management Area. A 

permitting process would be established to allow limited OHV use of this management area, 

while conserving the habitat and species in the area. An intensive resource and recreation 

monitoring and analysis program would be implemented in conjunction with the permitting 

process. There would be continued adjustments to the allowed level of use for the area based 

on the monitoring and analysis. During the first year of the permitting process, no more than 

525 vehicles would be allowed into the Adaptive Management Area by permit on any day. 

The first year would be designed to obtain information on visitor supply and biological needs 

and future permit numbers would be adjusted accordingly.

To ensure that world class recreational opportunities are continuously available at the ISDRA, 

a recreation mitigation process is defined in the RAMP. This process would replace areas that 

are closed to camping because they are sensitive areas (such as woodland microphyl) by 

developing new camping areas in less sensitive locations such as Gecko Road. 

The continued popularity of the ISDRA has attracted groups of individuals who frequent the 

ISDRA for its party atmosphere, rather than for recreational use. These individuals 

participate in lawless behaviors. The Alternatives in the EIS continue to emphasize a cooperative approach to law enforcement. Local, State and Federal law enforcement Officers, 

working together, would provide increased law enforcement. In addition, several 

management techniques could be implemented to increase law and order. These techniques 

include establishing curfews and restrictions in areas of historic lawlessness and limiting 
3

alcohol use to established camping areas. It is anticipated that increased law enforcement 

would restore a safe family atmosphere at the Imperial Sand Dunes Recreation Area. 

Alternatives

Four alternatives are considered in the EIS. They are:

Alternative 1: No Action Alternative

Alternative 2: Recreation and Resource Protection Alternative

Alternative 3: Natural and Cultural Resource Alternative

Alternative 4: Motorized Recreation Opportunities Alternative

Alternative 2 is the preferred alternative. The table below compares the alternatives:

Alternative 1 Alternative 2 Alternative 3 Alternative 4

Recreation This alternative 

does not place a 

limit on visitor 

supply.

This alternative 

will provide for 

a visitor supply 

of 80,444 

visitors on any 

day.

This alternative 

will provide for 

visitor supply of 

20,688 visitors 

on any day.

This alternative 

will provide for 

a visitor supply 

of 274,147 

visitors on any 

day.

Type of 

OHV Use

none in 

wilderness,

unlimited use in 

all other areas

8 areas, 

1 closed to OHV 

use, 

1 permit use 

only, 

6 unlimited use

8 areas, 

3 closed to OHV 

use, 

5 unlimited use

8 areas,

1 closed to OHV 

use, 

1 permit use 

only, 

6 unlimited use

ROS 

Classification

None 8 areas,

1 semi-primitive 

non-motorized, 

2 semi-primitive 

motorized,

3 roaded natural,

2 rural

8 areas,

3 semi-primitive 

non-motorized,

3 semi-primitive 

motorized,

2 roaded natural

8 areas,

1 semi-primitive 

non-motorized,

2 roaded natural,

3 rural,

2 urban
4

Acreage

(159,072 total 

BLM managed 

acres in ISDRA)

26,202 acres for 

Wilderness

132,870 acres 

for unlimited 

use 

26,202 acres for 

Wilderness

33,289 acres for 

permit use

99,581 acres for 

unlimited use

26,202 acres for 

Wilderness

41,394 acres for 

no OHV use

91,476 acres for 

unlimited use

26,202 acres for 

Wilderness

33,289 acres for 

permit use

99,581 acres for 

unlimited use

Air Quality No action Dust Control 

Plan

Dust Control 

Plan

Dust Control 

Plan

Public Safety 

Facilities

No Action New ranger 

station at 

Cahuilla and 

Buttercup, both 

for law 

enforcement and 

public 

education.

No new law 

enforcement 

facilities, but 

ranger public 

education 

facilities would 

be built at 

Osborne 

Outlook.

The temporary 

ranger station 

would remain at 

Buttercup.

New ranger 

station at 

Cahuilla and 

Buttercup.

Law 

Enforcement

Zero Tolerance 

Policy towards 

assaults, alcohol 

and drug abuse, 

and other 

serious 

violations.

Continue 

cooperative 

approach with 

other law 

enforcement 

agencies.

Zero Tolerance 

Policy towards 

assaults, alcohol 

and drug abuse, 

and other 

serious 

violations.

Continue 

cooperative 

approach with 

other law 

enforcement 

agencies.

Zero Tolerance 

Policy towards 

assaults, alcohol 

and drug abuse, 

and other 

serious 

violations.

Continue 

cooperative 

approach with 

other law 

enforcement 

agencies.

Zero Tolerance 

Policy towards 

assaults, alcohol 

and drug abuse, 

and other 

serious 

violations.

Continue 

cooperative 

approach with 

other law 

enforcement 

agencies.
5

Add new tools 

including 

curfews and 

restrictions in 

lawless areas 

and alcohol 

limitation. 

Visitor use and 

incident data 

will be 

monitored and 

will be used to 

evaluate the 

need for these 

tools and to 

develop the 

criteria for their 

use. These tools 

would be used 

as needed, but 

are not expected 

to be used 

continuously.

Strictly apply 

current laws and 

aggressive 

visitor education 

to address sand 

drag safety 

issues.

Add new tools 

including 

curfews and 

restrictions in 

lawless areas 

and alcohol 

limitation. 

Visitor use and 

incident data 

will be 

monitored and 

will be used to 

evaluate the 

need for these 

tools and to 

develop the 

criteria for its 

use. These tools 

would be used 

as needed, but 

are not expected 

to be used 

continuously.

 Strictly apply 

current laws and 

aggressive 

visitor education 

to address sand 

drag safety 

issues.

Add new tools 

including 

curfews and 

restrictions in 

lawless areas 

and alcohol 

limitation. 

Visitor use and 

incident data 

will be 

monitored and 

will be used to 

evaluate the 

need for these 

tools and to 

develop the 

criteria for its 

use. These tools 

would be used 

as needed, but 

are not expected 

to be used 

continuously.

 Strictly apply 

current laws and 

aggressive 

visitor education 

to address sand 

drag safety 

issues.

Social economic No free days Add 7 free use 

days in 

December.

Add 7 free use 

days in 

December.

Add 7 free use 

days in 

December.

Vending No change, 

vending would 

be allowed 7 

days a week in 4 

locations. 

Vendors would 

continue to 

compete with 

No changes until 

October 2003

Vending from 

noon Thursday 

through noon 

Monday at the 3 

short-term 

No changes until 

October 2003

Vending from 

noon Thursday 

through noon 

Monday at the 3 

short-term 

No changes until 

October 2003

Vending from 

noon Thursday 

through noon 

Monday at the 1 

short term 
6

private 

landowner 

businesses 

located adjacent 

to the ISDRA.

vending areas. 

Additional 

vending days are 

allowed around 

holiday periods.

1 long term 

vending area (7 

days a week.)

vending areas. vending area.

Additional 

vending days are 

allowed around 

holiday periods.

3 long-term 

vending areas (7 

days a week.)

Fiscal No Change, 

BLM would be 

dependant on 

grants and 

appropriations 

to provide 

services at the 

ISDRA in 

addition to some 

funding from 

recreation fees.

Develop a 

Business Plan to 

move towards a 

fee-based 

program.

Reduce 

dependence on 

grants and 

federal 

appropriations.

Develop a 

Business Plan to 

move towards a 

fee-based 

program.

Reduce 

dependence on 

grants and 

federal 

appropriations.

Develop a 

Business Plan to 

move towards a 

fee-based 

program.

Reduce 

dependence on 

grants and 

federal 

appropriations.
7

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CHAPTER 1

INTRODUCTION AND BACKGROUND

Introduction

The Bureau of Land Management (BLM) has prepared this Environmental Impact Statement 

(EIS) to analyze the potential environmental impacts resulting from the revision and updating 

of the Recreation Area Management Plan and Environmental Assessment for the Imperial 

Sand Dunes (BLM, 1987). A revised Recreation Area Management Plan (RAMP) would 

provide direction and guidance on the management of land use and resources of the Imperial 

Sand Dunes Recreation Area (ISDRA) that would be consistent with current public needs 

and resources status. Implementing a revised RAMP would also constitute an amendment to 

the CDCA Plan, in accordance with BLM planning regulations (43 Code of Federal 

Regulations [CFR] 1610.3-2). This EIS is prepared in accordance with National 

Environmental Policy Act (NEPA) of 1969, as amended, the President’s Council on 

Environmental Quality Guidelines for the implementation of NEPA, and the BLM NEPA 

Handbook. The BLM is the lead agency for this EIS, and maintains primary responsibility 

for compliance with NEPA for actions on federal lands it manages. In addition, the BLM is 

responsible for consulting with the United States Fish and Wildlife Service (USFWS) to 

ensure that the preferred alternative complies with the Endangered Species Act (ESA). 

The ISDRA, which comprises the largest mass of sand dunes in California, is located in 

Imperial County. The ISDRA is recognized as a world-class off-highway vehicle (OHV) 

recreation area because of the outstanding opportunities it presents for OHV recreational 

activities (BLM, 1987). It is one of the most popular OHV areas in the western United 

States, as evidenced by over 3 million OHV visitor-use days that occur annually at the 

ISDRA (BLM, 2001). In addition, the ISDRA provides unique habitat for several endemic 

and sensitive plant, insect, and animal species.

The ISDRA provides outstanding recreation opportunities for OHV recreation to the southern 

California region and the southwestern Arizona vicinity. To fulfill its obligations under the 

Federal Land Policy Management Act (FLPMA) and under the Endangered Species Act 

(ESA), the BLM manages recreational use after considering the effects of the recreational 

activities on the conditions of special-status species, and other unique natural and cultural 

resources. The FLPMA directs that the BLM’s management of public lands emphasize 

“multiple use and sustained yield unless otherwise specified by law” and that “public lands 

be managed in a manner that will protect the quality of scientific, scenic, historical, 

ecological, environmental ... values” (43 U.S.C. 1701 Sec. 102(a)(7)(8)). The type and level 

of OHV use, in particular, must also be carefully managed to create an environment that 

promotes the health and safety of visitors, employees, and nearby residents. 
10

Continued population growth in southern California and Arizona and the expanding 

popularity of OHV recreation has resulted in a steady increase in demand for outdoor 

recreation at the ISDRA. From 1985 to the present, the number of visits to the ISDRA has 

roughly tripled (BLM, 1987 and 2001a). There have also been minor occurrences of 

occasional trespasses in the North Algodones Dunes Wilderness and on private lands, which 

has resulted in some conflicts among OHV enthusiasts, landowners, and concerned members 

of the public. Growing attendance, including an increasing number of individuals who visit 

the ISDRA for a party atmosphere, rather than for OHV recreation, also underlies, in part, the 

increased incidence of law enforcement violations.

This EIS is organized in four chapters. The remainder of Chapter 1 describes the purpose 

and need for revising and updating the 1987 RAMP, project setting, regulatory context, and 

issues concerns and opportunities identified during the scoping activities. Chapter 2 

describes the alternatives (including the No Action and the action alternatives). The Affected 

Environment is described in Chapter 3, and Chapter 4 addresses and analyzes the 

environmental impacts, including the cumulative impacts, of the alternatives (including the 

No Action Alternative). Chapter 5 summarized the coordination and consultation for this 

project. Chapters 6, 7, and 8 include a list of document authors, references, and a combined 

glossary and list of acronyms, respectively. Appendix A contains a summary of the public 

comments and BLM’s responses to these comments. Appendix B contains the monitoring 

plan. Appendix C contains reference air quality data.

Purpose and Need

As noted in BLM Manual 8322, a recreation area management plan... . “identifies the 

management actions to be implemented to achieve recreation related decisions... . is the link 

between the allocation of land for recreation use in the multiple-use planning process and the 

actions necessary to implement such allocations.” (BLM Manual 8322.05A). 

Purpose

The purpose of revising the 1987 Recreation Area Management Plan (RAMP) is to develop a 

guide for all resource management activities and to establish management actions for the 

ISDRA. A revised RAMP that updates the 1987 RAMP would be designed to provide a 

variety of sustainable OHV and other recreational activities, and to maintain or improve the 

conditions of the special-status species and other unique natural and cultural resources, while 

creating an environment to promote the health and safety of visitors, employees, and nearby 

residents. The purpose of the plan is to develop a RAMP to establish:

- Multiple use goals and ecosystem management prompts

- Management actions that fulfill the requirements of the Federal Land Policy and 

Management Act of 1976

- Management direction and actions applying to future activities in specific 

management areas, and
11

- Monitoring and evaluation requirements.

The RAMP embodies the provisions of the Federal Land Policy and Management Act, the 

implementing regulations, and other guiding documents. It is developed in accordance with 

the CDCA Plan and would amend portions of the CDCA Plan pertaining to recreation 

management in the ISDRA. It revises and replaces the 1987 RAMP.

The purpose of the project is to:

- Provide a process to allow the maximum recreational use of the ISDRA while 

maintaining the unique and diverse habitat of the dunes system. This process will 

allow adaptive use of at least one large geographical area with monitoring and 

evaluation of the habitat and the abundance of specific species. The monitoring and 

evaluation data will be used to make adjustments to the recreational use of the 

geographical area.

- Develop a large continuous geographical area for habitat and species conservation. 

This area will include all of the habitat types that are present in the dunes system. It 

is important that this area is continuous and that the habitat is not fragmented. 

Although this geographical area will be available for OHV and other recreational 

uses, the recreational use, habitat condition and species abundance will be monitored 

and the recreational use of the area will be adjusted as needed to conserve the habitat 

and species.

- Utilize sound science when making decisions concerning species conservation and 

multiple use of the ISDRA.

- Specify what levels of visitor use can be provided for motorized vehicle use in the 

ISDRA while maintaining the habitat requirements for special status species, 

conserving cultural resources, providing reasonable consideration for other important 

natural resources and promote the health and safety of visitors, nearby residents, 

employees and other service providers in the ISDRA. Institute measures to achieve 

specified visitor use levels. Establish criteria for modifying those measures or 

instituting additional measures if needed in the future based on monitoring of visitor 

use and the conditions and trends of special status species, cultural resources and 

important natural resources.

- Identify the type and level of visitor services, including facilities, needed to support 

desired visitor use. For services to be provided by BLM, the RAMP could identify 

cost for these services. The RAMP would establish a fee system such that the 

appropriate level of visitor services can be provided in an efficient, cost-effective 

manner.
12

- Guide the ISDRA beginning in 2002. It will normally be revised every ten years, but 

may continue to be used for up to fifteen years. It may be amended or revised at any 

time if the BLM Field Manager determines that conditions in the ISDRA have 

changed beyond those anticipated by this Plan, or if monitoring or project-level 

environmental analysis indicate a need for a change in management direction. 

- Implement the EIS Preferred Alternative. It is the alternative the State Director has 

determined would most benefit the public. Careful consideration was given to 

coordinating and balancing various conflicting resource uses to arrive at a sustainable

mix. 

- Establish priorities. Management area allocations, actions, monitoring and evaluation 

requirements constitute a statement of BLM’s intended direction. However, projected 

outputs, services and rates of implementation are contingent upon obtaining funding, 

including user fees, grants, agreements and the annual budgeting process.

The purpose of the CDCA Plan Amendment is to amend the CDCA Plan to remain consistent 

with the alternative that is selected in the Record of Decision. 

Need 

The ISDRA offers outstanding opportunities for OHV and other recreation in the California 

Desert District. In order to fulfill its management obligations under federal regulations, the 

BLM must carefully manage OHV recreation, so that the conditions of the special status 

species, and other unique natural and cultural resources are maintained or improved. The 

type and level of OHV recreation also must be carefully managed to create an environment 

that promotes the health and safety of visitors, employees, and nearby residents. 

Since the previous plan was written in 1987, several of the projects identified have been 

implemented. Of the projects that were not implemented, some are no longer feasible. 

Therefore, it is critical to revisit some of the past decisions and determine whether or not new 

courses should be charted. 

Since the 1987 RAMP, several regulatory changes have taken place that relate to the ISDRA. 

The U.S. Fish and Wildlife Service listed the Peirson’s milk-vetch as a Federally threatened 

plant. The flat-tailed horned lizard had been proposed as Federally threatened and then 

withdrawn by the U.S. Fish and Wildlife Service. Public Law 103-433 designated the North

Algodones Dunes Wilderness in 1994. Public Law 103-433 released Wilderness Study Area 

362 from further studies concerning its suitability for wilderness designation. Analyzing this 

new information may lead to different management decisions in the future. 

The proximity of the Imperial Sand Dunes Recreation Area to private land and the wilderness 

area requires that the BLM carefully manage the recreation, natural, and cultural resources 

and corresponding resource values (such as “scenic values”) within the planning area to 

reduce potential impacts to these areas. 
13

Southern California’s continued population growth in the urban and non-urban areas and 

shifting demographic patterns have increased the demand for outdoor recreation at the 

ISDRA and nearby areas. It continues to be a management challenge to encourage 

appropriate recreational use, discourage inappropriate use, while respecting the freedom of 

visitors to enjoy the ISDRA.

In addition to discussing the positive recreational uses of the ISDRA, this plan discusses a 

variety of issues, their proposed solutions and opportunities for creative improvement.

On the basis of the purpose and need for this action and on the issues, concerns, and 

opportunities that were identified during the public scoping process, the BLM will establish 

long-term goals that describe desired conditions to be achieved during the implementation 

period of a revised RAMP.

ISDRA Overview

Location

The ISDRA is located in Imperial County, in southeastern California approximately 25 miles 

west of the Colorado River and immediately north of the border between the United States 

and Mexico. This area is shown in Figure 1-1, Regional Vicinity. Access to the ISDRA is 

provided primarily by State Route (SR)-78 in the north, and Interstate (I)-8 in the south. The 

town of Brawley is located approximately 25 miles to the west, and the City of El Centro is 

located 40 miles southwest. The small settlement of Glamis is located within the ISDRA 

where SR-78 crosses the Union Pacific (formerly the Southern Pacific) Railroad. East of the 

ISDRA are the Cargo Muchacho Mountains and Chocolate Mountains. This area includes 

the Chocolate Mountain Aerial Gunnery Range, which is used by the U.S. military for target 

practice. The Salton Sea is located approximately 25 miles northwest of the ISDRA.

ISDRA Planning Area

The Planning Area for the evaluation conducted in this EIS encompasses the ISDRA and a

one-mile area around the ISDRA that is actually managed in two other BLM plans: the 

Northern and Eastern Colorado Desert Coordinated Management Plan (NECO) and the 

Western and Eastern Colorado Desert Route of Travel Plan (WECO ROT). This one-mile 

area is not a part of the ISDRA, although it is included as a part of the planning area since 

BLM is required to analyze the off-site impacts. This one-mile area around the ISDRA is 

referred to as the “planning area” in this EIS and the associated RAMP. 

The ISDRA comprises approximately 167,000 acres of land in California, covering an area 

more than 40 miles long and averaging 5 miles in width. The regional setting of the ISDRA 

is shown in Figure 1-1. Of this total acreage of ISDRA approximately 159,000 acres are 

managed by BLM, 7,000 acres are privately owned, and 900 acres are owned by the State of 

California. In addition the one-mile wide area around the ISDRA boundary within the 

planning includes approximately 48,300 acres of BLM managed land, approximately 1,800 

acres of military managed land and approximately 9,100 of privately owned land. The dunes 
14

are bordered on the west by the Coachella Canal, which delivers Colorado River water to the 

agricultural industry of the Imperial Valley to the north and west. A major route of the 

Union Pacific Railroad traverses the eastern edge of the ISDRA. SR-78 divides the northern 

third of the ISDRA from the southern portion. Interstate 8 traverses the southern portion of 

the ISDRA. Ogilby Road runs north south between SR-78 and I-8 along the southeast 

portion of the ISDRA. The ISDRA Plan Area is shown in Figure 1-2.

Topography

The dune system of the ISDRA is situated on a relatively flat plain that has an elevation of 

approximately 50 feet above sea level. On the west, the plain is referred to as the East Mesa 

because it is east of the Imperial Valley. On the east, the plain is called Pilot Knob Mesa. 

The dunes reach heights of 300 feet above the plain and include classic examples of several 

different types of dunes. The sands are believed to originate largely from the eroded beaches 

of ancient Lake Cahuilla. The beaches themselves are remnants from times when the 

Colorado River temporarily was diverted from its southward course, and emptied into the 

Salton Trough, forming ancient Lake Cahuilla. Unlike some major dune systems that have 

formed next to a mountain range as a result of blocking topography, the Imperial Sand Dunes 

(also known as the Algodones Dunes) have formed primarily as a result of opposing seasonal 

winds. Winter winds come from the northwest, but often reverse to the southeast in summer. 

The stronger winter winds bring sands from the Salton Trough, and appear to be slowly 

pushing the dune system southeastward.

Largely as a result of the dominance of northwesterly winds, the east and west portions of the 

dune system differ substantially in character. West side sands are composed of material that 

is generally heavier and coarser than the lighter, finer sands carried further east and south by 

the prevailing winds. The coarse sands form the largest, tallest dunes, located in the western 

two-thirds of the dune system and constitute the “primary dunes.” The tallest dunes are 

found toward the center of the overall dune mass, in the eastern half of the primary dune 

area. East of the primary dunes are the “secondary dunes,” smaller dunes composed of finer 

sands and having more vegetation cover.

Climate

The ISDRA is located in a desert region of long, hot summers; mild winters; low rainfall; 

low relative humidity; and a high percent of sunny days. Summer daytime temperatures 

routinely exceed 105 degrees Fahrenheit. Annual precipitation fluctuates widely but 

averages just over 2 inches. Winter daytime highs are in the 60 degrees Fahrenheit to 70 

degrees Fahrenheit range from December through March, and freezing temperatures are rare. 

Winter winds approach from the northwest. Summer winds are more variable, but often 

blow from the southeast.
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ISDRA Plan Area - 105kb 
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Visitor Use Patterns

Visitation to the ISDRA has increased dramatically since 1987. Data from 1987 Recreation 

Area Management Plan indicate that approximately 225,900 visits were made to the ISDRA 

in 1985. In comparison, visits to the ISDRA during the last 2 years have averaged more than 

1.4 million visits per year. Visitor use patterns are discussed throughout Chapters 3 and 4 of 

this EIS as they pertain to the affected environment and environmental impacts.

Relationship To Policies, Plans, And Programs

Implementation of a revised management plan for public lands is subject to numerous laws 

and regulations, as well as a general requirement for consistency with pre-existing and 

applicable plans. The following sections summarize the most pertinent policies, plans, and 

programs that affect the planning processes at the ISDRA. 

Federal Land Policy Management Act

The Federal Land Policy Management Act (P.L. 94-579, 90 Stat. 2743, 43 U.S.C. 1701 et 

seq.) provides the BLM with an operating mandate to emphasize the concepts of multiple use 

and sustained yield. Section 202(c) of FLPMA requires the BLM to “use and observe the 

principles of multiple use and sustained yield” in developing land use plans for public lands. 

Multiple use is a concept that directs publics lands and their resource values be managed in a 

way that best meets the present and future needs of the people of the country. Multiple use 

involves “a combination of balanced and diverse resource uses that takes into account the 

long-term needs of future generations for renewable and nonrenewable resources... ” 

(FLPMA, Section 103). Sustained yield is “the achievement and maintenance in perpetuity 

of a high-level annual or regular periodic output of the various renewable resources of the 

public lands consistent with multiple use” (FLPMA, Section 103). The BLM is directed by 

FLPMA to manage sustained yield consistently with multiple use. The California Desert 

Conservation Area (see Section 1.3.2) was created through Section 601 of FLPMA.

California Desert Conservation Area Plan

The CDCA encompasses 25 million acres of land in Southern California that was designated 

by Congress in 1976 through FLPMA. The BLM directly administers about 10 million acres 

of the CDCA. With the designation of the CDCA, Congress directed the BLM to prepare 

and implement a comprehensive, long-range plan for the management, use, development, and 

protection of public lands within the CDCA. The 1980 CDCA Plan, as amended, is based on 

the concepts of multiple use, sustained yield, and maintenance of environmental quality. The 

CDCA Plan provides overall regional guidance for management of the public lands in 

CDCA, and establishes long-term goals for protection and use of the California Desert. The 

CDCA Plan establishes four multiple-use classes, multiple-use class guidelines, and plan 

elements for specific resources or activities such as motorized-vehicle access, recreation, and 

vegetation. These multiple-use classes (MUCs) are:
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Class C (Controlled): About 4 million acres are Class C. These include 69 

wilderness areas totaling 3,667,020 acres created by Congress with the October 1994 

passage of the California Desert Protection Act (CDPA). These lands are to be 

preserved in a natural state; and access generally is limited to Non-Motorized, nonmechanized means (i.e., by foot or horseback).

Class L (Limited Use): About 4 million acres are Class L. These lands are managed 

to protect sensitive, natural, scenic, ecological, and cultural resource values. They 

provide for generally lower-intensity, carefully controlled multiple uses that do not 

significantly diminish resource values.

Class M (Moderate Use): About 1.5 million acres are Class M. These lands are 

managed in a controlled balance between higher-intensity use and protection. A wide 

variety of uses such as mining, livestock grazing, recreation, energy, and utility 

development are allowed. Any damage that permitted uses cause must be mitigated.

Class I (Intensive Use): About 500,000 acres are in Class I. These lands are 

managed for concentrated use to meet human needs. Reasonable protection is 

provided for sensitive natural values, and mitigation of impacts and rehabilitation of 

impacted areas will occur when possible. 

The CDCA also includes a designation for Areas of Critical Environmental Concern (ACEC) 

to protect sensitive cultural and natural resources. The ISDRA, including the ISDRA 

Planning Area includes three ACECs. Plank Road, located in the southern portion of the 

ISDRA, is a historic cultural resource protected by an ACEC. In the planning area, East 

Mesa near Gordon’s Well was designated an ACEC to protect habitat for the flat-tailed 

horned lizard (Phrynosoma mcallii), which was proposed for listing under the federal ESA as 

a “threatened” species and withdrawn. It currently is a BLM sensitive species. The Gold 

Basin-Rand Intaglios, located on the eastern edge of the ISDRA planning area, has unique 

prehistoric cultural resources values that are protected by an ACEC designation.

Since 1980, the CDCA Plan has been amended periodically to reflect changing conditions, 

including the acquisition of new knowledge relating to natural resources, and to update 

management strategies. Among these amendments is the 1987 ISDRA RAMP.

The RAMP could change certain parts of the CDCA Plan. Some of these changes include 

establishing new or modified areas as open, limited, or closed to OHV use and changing 

multiple use classes. Such changes require an amendment to the CDCA Plan in accordance 

with BLM planning regulations, Part 43, Code of Federal Regulations, Subpart 1610.3-2.

California Desert Protection Act

The California Desert Protection Act (CDPA) of 1994 (P.L. 103-433) created new wilderness 

areas on federal lands in the CDCA, transferred considerable acreage from BLM to National 

Park Service management, changed the status of several former monuments and preserves to 

national parks, and created several special designations for wildlife sanctuaries and areas of 
21

critical environmental concern. The enactment of the CDPA formally established 

26,202 acres in ISDRA as the North Algodones Dunes Wilderness area. 

Prior to passage of the CDPA, BLM studied both the North Algodones and South Algodones 

Wilderness Study Areas of the ISDRA for possible wilderness designation under section 603 

of the Federal Land Policy and Management Act. On January 3, 1989, Senator Alan Cranston 

proposed these Wilderness Study Areas, along with 69 other areas of the CDCA, to be 

designated as wilderness in Senate Bill 11 (S-11). The bill did not pass and was reintroduced 

by Senator Feinstein in 1993 as Senate Bill 21. Senator Feinstein, in a February 23, 1994, 

correspondence to her Senate colleagues asking for their support of the Bill, stated that she 

wanted to "... drop the entire 61,630 acre South Algodones Dunes from the bill to allow 

vehicle use." 

On October 31, 1994, the CDPA was signed into law. The Act designated as wilderness the 

26,202 acre North Algodones Dunes to be managed by BLM as a part of the National 

Wilderness Preservation System. No wilderness was designated for the South Algodones in 

the Act. Congress also indicated in the CDPA that the South Algodones Dunes Wilderness 

Study Area had been adequately studied for wilderness designation pursuant to Section 603 

of FLPMA, and would be released from Wilderness Study Area status. Since conditions 

relating to the wilderness values of the South Algodones Dunes have not changed since the 

1994 Act, BLM will not review the area under Section 201 or 202 of FLPMA.

 

1987 Recreation Area Management Plan and Environmental Assessment

The ISDRA was designated first by a management plan adopted in 1972. A Recreation Area 

Management Plan was adopted in 1987 and included management prescriptions for the 

following: recreation opportunities, safety/emergency services/visitor protection, resource 

protection, protection of wilderness suitability, public contact and interpretation, facility 

development, operations and maintenance, concessions and vendors, access easements and 

land acquisitions, and compatibility of land uses.

Because of budgetary considerations and environmental factors, portions of the 1987 RAMP 

have not been implemented. The 1987 Environmental Assessment (EA) for this management 

plan analyzed potential environmental consequences resulting from implementation of the 

plan, and three other alternative management programs for the ISDRA. The 1987 Recreation 

Area Management Plan is outdated and will be fully replaced by the new RAMP. 

Interim Closures / Temporary Camping Closure

On March 16, 2000, the Center for Biological Diversity, and others (Center) filed for 

injunctive relief in U.S. District Court, Northern District of California (court) against the 

Bureau of Land Management (BLM) alleging that the BLM was in violation of Section 7 of 

the Endangered Species Act (ESA) by failing to enter into formal consultation with the U.S. 

Fish and Wildlife Service (FWS) on the effects of adoption of the California Desert 

Conservation Area Plan (CDCA Plan), as amended, upon threatened and endangered species. 

On August 25, 2000, the BLM acknowledged through a court stipulation that activities 
22

authorized, permitted, or allowed under CDCA Plan may adversely affect threatened and 

endangered species, and that the BLM is required to consult with the FWS to insure that 

adoption and implementation of the CDCA Plan is not likely to jeopardize the continued 

existence of threatened and endangered species or to result in the destruction or adverse 

modification of critical habitat of listed species. 

Although BLM has received biological opinions from the USFWS on selected activities, 

further consultation is required on the overall CDCA Plan to address the cumulative impacts 

of all the activities authorized by the CDCA Plan. In the absence of consultation on the 

entire CDCA Plan, the impacts of individual activities, when added together with the impacts 

of other activities in the California Desert, are not known. The BLM entered into 

negotiations with plaintiffs (Center for Biological Diversity, and others) for establishing 

interim actions to be taken to provide protection for endangered and threatened species 

pending completion of USFWS consultation on the CDCA Plan in total. Agreement on these 

interim actions avoided litigation of the plaintiffs’ request for injunctive relief and the threat 

of an injunction prohibiting all activities authorized under the Plan. These interim agreements 

have allowed BLM to continue to authorize some level of activities throughout the ISDRA 

during the lengthy consultation process and to provide protection to listed species until the 

long term management can be determined through this EIS and associated RAMP. 

By taking interim actions, as allowed under Part 43 of the Code of Federal Regulations (43 

CFR Subpart 8364), the BLM contributes to the conservation of endangered and threatened 

species in accordance with Section 7(a)(1) of the federal ESA. The BLM also avoids making 

any irreversible or irretrievable commitment of resources that would foreclose any 

reasonable and prudent alternative measures that might be required as a result of the 

consultation on the CDCA Plan in accordance with Section 7(d) of the ESA.

On November 3, 2000, a legal stipulation respecting the Peirson’s milk-vetch (Astragalus 

magdalenae var. peirsonii), designated as threatened under the ESA, became effective and 

five areas in the ISDRA were closed to motorized vehicle use. The closure boundaries are 

identified by sign posts and identified in the Amended Stipulation and Order Concerning 

Injunctive Relief for the Peirson’s Milk-Vetch, Case No. C-00-0927 WHA-JCS. Four 

closure areas were named, while the fifth parcel was unnumbered, but was described as the 

Patton Valley Area. These areas are delineated in Figure 1-3, and total approximately 49,000 

acres.

On October 18, 2001, the legal stipulation respecting the desert tortoise (Gopherus agassizii), 

also designated as threatened under the ESA, became effective; and a temporary camping 

closure on approximately 25,600 acres of desert tortoise habitat was approved. The camping 

closure is located east of Glamis and the Union Pacific Railroad (see Figure 1-3). As with 

other ISDRA management directions, the camping restriction does not apply to private lands 

within the closure area, nor does it restrict the use of motorized vehicles on existing routes of 

travel otherwise allowed by the CDCA Plan and 1987 RAMP. 
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Northern and Eastern Colorado Desert Coordinated Management Plan

The Northern and Eastern Colorado (NECO) Desert Coordinated Management Plan area is 

adjacent to the ISDRA but does not overlap the ISDRA. It is the management plan for the 

eastern side of the planning area. The NECO Plan addresses several issues including: 

(1) recovery of the desert tortoise, (2) conservation of the variety of other species and 

habitats, and (3) public lands access and uses. The NECO Plan provides a wide range of 

actions that relate primarily to land use allocations and on-the-ground actions. The BLM will 

coordinate management decisions so that the management of the ISDRA areas that are 

adjacent to the NECO areas is consistent, whenever practical.

Western Colorado Desert Route of Travel Plan 

The Western Colorado Desert Route of Travel (WECO ROT) Plan area is adjacent to the 

ISDRA but does not overlap the ISDRA. (However, most of the ISDRA is within the area 

referred to by BLM as the Western Colorado Desert area.) WECO ROT is the management 

plan for the western side of the planning area. The WECO ROT Plan addresses several 

issues including: (1) public lands access and uses, (2) recovery of the flat-tailed horned 

lizard, (3) conservation of the variety of other species and habitats, and sensitive cultural 

resources. The WECO ROT Plan designates routes of travel and camping in Imperial 

County. The BLM will coordinate management decisions so that the management of the 

ISDRA areas that are adjacent to the WECO ROT areas is consistent, whenever practical.

Other Plans and Programs

The following plans and programs are directly or indirectly applicable to the planning 

process at ISDRA. An updated recreation area management plan will take these plans and 

programs into account, and incorporate appropriate elements: 

Wilderness Implementation Strategy (WIS), August 31, 1999. This strategy will continue to 

be used to manage the North Algodones Wilderness Area of the ISDRA.

National Management Strategy for Motorized Off-Highway Vehicle Use on Public Lands 

(January 2001). 

State Implementation Plan For PM10 in the Imperial Valley, Executive Summary, Final 

(1993). The ISDRA falls within the Salton Sea Air Basin, which is classified as a nonattainment area for particulate matter with a diameter less than 10 micrometers (PM10) based 

on federal Clean Air Act standards. Planning efforts at ISDRA will be consistent with the 

State of California Air Quality Implementation Plan.

County of Imperial General Plan (1996): This plan seeks to direct growth, particularly urban 

development, to suitable areas in Imperial County. 
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California Desert District Business Plan Recreation Fee Demonstration Project: This plan 

will be utilized in the development of fees. 

Algodones Dunes Habitat Management Plan (1987): An updated Recreation Area 

Management Plan will amend this document and will take precedence in management 

decisions.

Wildlife Habitat Protection Program: The monitoring program in the RAMP would 

supplement this program.

Imperial County Emergency Medical Services ALS/BLS Treatment Protocols, as Amended: 

The BLM provides basic life support in the ISDRA following this plan.

Interpretive Plan for the El Centro Resource Area (1991): This document provides a 

framework for interpretative services and development on public lands in the El Centro 

Resource Area. The ISDRA interpretative services will be developed in accordance with this 

plan.

Law Enforcement Special Evaluation, Law Enforcement in the California Desert (2000)

El Centro Law Enforcement Plan. This plan establishes general guidelines for law 

enforcement for the El Centro Field Office.

Mineral Resources of the North Algodones Dunes Wilderness Study Area (1984).

Plank Road Areas of Critical Environmental Concern Management Plan (1985).

Desert Tortoise Recovery Plan, U. S. Fish and Wildlife Service. The ISDRA is within the 

range of the desert tortoise but is not within critical habitat or any existing or proposed 

reserve area.

Flat-Tailed Horned Lizard Range-wide Management Strategy (1997).

Volunteer Opportunities with the Bureau of Land Management in the El Centro Resource 

Area.

Endangered Species Act

The ESA provides for the federal protection of threatened plants, insects, fish, and wildlife. 

The USFWS administers the ESA on behalf of the United States. The major components of 

the ESA include:

Provisions for the listing of threatened and endangered species

The requirement for consultation with USFWS on federal projects

Prohibitions against the taking of listed species
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Provisions for permits to allow incidental taking of threatened and endangered 

species

As noted previously, the RAMP was reviewed by USFWS in accordance with Section 7 of 

the ESA. Under Section 7, the BLM is required to consult with the USFWS to ensure that 

any actions authorized, funded, or carried out are not likely to “jeopardize the continued 

existence of any endangered species or threatened species or result in the destruction or 

adverse modifications of lands determined by USFWS to be ‘critical habitat’.”

Planning Issues

Issues, Concerns, and Oppor tunities

A preliminary step in developing the management program for the current RAMP involved 

identifying relevant issues, concerns, and opportunities. These issues, concerns, and 

opportunities were identified with assistance from the public. The public helped to identify

what long-term levels of recreational use, services, goods, and environmental conditions are 

expected from the ISDRA. The issues, concerns, and opportunities help to determine the 

extent that the 1987 RAMP would need to be revised. The issues, concerns, and 

opportunities provide information to be considered in developing alternatives for future 

management of the area.

The 1987 RAMP was used as a reference point to begin identifying issues, concerns, and 

opportunities. Many of the issues identified during the 1987 planning process remain 

relevant. Additional issues, concerns, and opportunities were identified through a series of 

seven public meetings conducted during 2000 and a project comment site on the BLM’s 

INTERNET website. Public participation was encouraged through news releases, a 

publication in the Federal Register, and a mailing of approximately 2,000 newsletters to 

individuals, groups, and organizations. To further this process, an interdisciplinary working 

group also was developed from several interested public organizations. The working group 

consisted of four members representing the following: OHV/Dune Groups, Environmental 

Groups, Imperial County, and BLM.

Using written and verbal comments, the working group identified a series of public issues, 

management concerns, and resource opportunities. Issues, concerns, and opportunities 

dealing specifically with the ISDRA that had been identified at previous public meetings, but 

had been deferred, also were included for consideration. The BLM Field Manager reviewed 

all issues, concerns, and opportunities. The issues, concerns, and opportunities were also 

validated through an “Issues Newsletter” mailed to approximately 600 interested individuals 

and organizations on the BLM’s mailing list. The newsletter included a response form to add 

or further refine issues.

This effort was supplemented in August and September 2001 by another newsletter mailing 

to approximately 2,000 interested individuals and organizations seeking public input, and 
28

through three additional public meetings held in El Centro and San Diego, California, and 

Phoenix, Arizona. 

Only issues, concerns, and opportunities meeting certain criteria were included in the 

planning process. To be included, an issue, concern, and opportunity had to be:

- Consistent with federal statute and within the jurisdiction of the BLM

- A land management or administrative concern

- Able to be resolved during the planning process

- Producing of a significant long-term effect through its resolution

- Related to the ISDRA

Issues, Concerns And Opportunities

The following issues, concerns, and opportunities captured as a series of questions, were

carried forward in the present RAMP management process:

1. What level or levels of recreation setting will be provided at the ISDRA?

The ISDRA can provide a wide variety of outdoor settings. Currently the majority of the 

area is an undeveloped setting where recreational enthusiasts can engage in activities that are 

not dependent on facilities and experience a moderate level of self-reliance and risk. Natural 

resources in these areas have not been modified to accommodate human use. About 25% of 

the ISDRA is in a more developed setting where many of the activities are based at or near 

facilities. Natural resources in these areas have been significantly modified to accommodate 

human use. There are currently no guidelines to direct the development, or lack of 

development, of any of the areas associated with the ISDRA. Public opinion varies as to what 

range of settings should be accommodated at the ISDRA.

2. How will OHV recreation be managed in relation to resources and other recreational 

activities, including safety?

Federal regulations at Title 43 CFR Part 8340.0-2 requires BLM to protect the resources of 

the public lands, promote the safety of all users of those lands, and minimize conflicts among 

the various users of those lands. Both advocates and opponents of OHV use are concerned 

about how to manage this activity to minimize impacts on other resources and to be 

compatible with other recreational activities. The concern focuses around the issues of 

public health and safety resulting from crowding in some OHV areas, saving camp spots, 

dumping of gray water and litter. There are also concerns with quiet times, camp area speed 

limits and the general unruliness of some visitors. Finally, there is a more general concern 

about the potential adverse affects of OHVs on plants, wildlife, geologic resources and other 

elements of the ISDRA environment. 

3. How much facility development and access is appropriate for the ISDRA?
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This issue addresses the suitability of the area to accommodate additional camp pads, contact 

stations, roads, etc. Chapters III and IV provide a complete description of the facility 

development anticipated in the next ten years.

4. How often, where and what should vendors/concessionaires be allowed to operate on 

public land in the ISDRA to best serve the needs of the public?

This issue addresses the vendor program in the ISDRA. A revised RAMP could determine 

what food, goods, or services should be provided by vendors in order to enhance OHV use 

and camping in ISDRA. A permitting program could provide structure, including time 

limitations for the vending program. The RAMP could designate geographical areas where 

vending could be permitted. 

5. How much impact are the tour buses having on the facilities at the ISDRA and should 

there be compensation for that use?

There has been a notable increase in visitation to ISDRA by commercial tour buses since the 

1987 RAMP was completed. Since the reconstruction of the Osborne Overlook access road 

and the installation of the pit toilets at the Buttercup Campground, several commercial tour 

bus companies regularly stop and utilize the facilities. Identification of these companies is 

difficult due to staffing levels and uncontrolled access to the recreation area. Both areas are 

BLM managed and maintained roads with commercial vehicle weight limits. It is 

undetermined if the tour bus traffic significantly increases the level of maintenance and 

repairs required for the roads and restrooms. It is also undetermined if there are any 

recreational or resource conflicts.

Federal regulations, Title 43 CFR Parts 2930 and 8370, address issuance of permits for 

recreation on public lands. These regulations allow the BLM to issue permits in order to 

manage recreational use, reduce recreational and resource conflicts, and to receive a return 

for commercial uses of public lands.

6. How will the BLM conserve the unique natural resources of the ISDRA in an area 

managed for OHV use? 

The Endangered Species Act of 1973 and the environmental polices of the BLM provide for 

protection of federal or state listed species on public lands in California. BLM consults with 

the U.S. Fish and Wildlife Service and discussed concerns with the California Department of 

Fish and Game on actions that may affect listed species, such as this management plan. The 

listed and sensitive species identified in the area are described below.

The Algodones Dunes are home to five special status plant species: the Peirson’s milk-vetch, 

which is listed as threatened under the Endangered Species Act and endangered under 

California Endangered Species Act, the Algodones Dunes sunflower which is listed as 

endangered under California Endangered Species Act, Wiggins croton which is listed as rare 

by the State of California, and sandfood and giant Spanish needle which are considered rare 

and endangered, respectively, by the California Native Plant Society. 
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One former federal candidate species and BLM sensitive lizard species, the flat-tailed horned 

lizard, occurs in relatively low densities at the ISDRA. The Colorado Desert fringe-toed 

lizard, a former federal candidate species and BLM sensitive species, is abundant at the 

ISDRA, especially in active dunes and psammophytic scrub. Additionally, the federally and 

state listed threatened desert tortoise probably occurs in the microphyll woodlands on the east 

side of the ISDRA, as does the Gila woodpecker, a state listed endangered species. 

Additionally, the BLM sensitive Couch’s spadefoot toad probably occurs in the microphyll 

woodlands on the east side of the ISDRA. The toad is also a state species of concern.

The creosote bush scrub and microphyll woodland habitats adjacent to the ISDRA probably 

contain the BLM sensitive species, the burrowing owl, which is also a state species of 

concern. The loggerhead shrike, leConte’s thrasher and Yuma mountain lion, all species of 

concern, also occur at the ISDRA. Additionally, three poorly known beetle species, all BLM 

sensitive species, occur at the ISDRA: Andrew’s dune scarab beetle, Hardy’s dune beetle and 

Carlson’s dune beetle.

A revised RAMP will address conservation of these species while maintaining recreational 

use of the ISDRA.

7. What level of education and resource interpretation should be provided at the 

ISDRA?

This issue addresses the type of interpretive materials (signs, brochures, etc) that should be 

available to the public to better educate and communicate to them on the critical resources 

and regulations of the ISDRA.

8. How will education, law enforcement, and other techniques be used to ensure 

compliance with laws and regulations at the ISDRA?

Federal regulations, Title 43 CFR Part 8340.0-2, directs BLM to protect the resources of the 

public lands, to promote the safety of all users of those lands, and to minimize conflicts 

among the various users of those lands.

An ever-increasing visitor population during the high use season has created larger crowds in 

the camping and riding areas. Along with this there seems to be an increase in irresponsible 

visitors who act without regard to the consequences to themselves or others. The need to 

develop an educational program to raise the level of awareness of the rules, regulations, and 

safety concerns was identified by the public. The need to develop better ways of 

disseminating information to visitors through the use of the INTERNET and partnerships 

with the various user groups and businesses that focus on the ISDRA was also identified. 

This issue addresses the identification of options available to aid in increasing lawful 

behavior. 
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9. What is considered to be the Visitor Supply at the ISDRA? Is it being exceeded and if 

so, what actions should be taken?

This issue addresses the number of visitors that are coming to the ISDRA. The visitor supply 

could be determined by use of the Recreation Opportunity Spectrum. The Recreation 

Opportunity Spectrum is a system that provides guidelines to manage recreational 

opportunities, available facilities and visitor supply. This tool could allow BLM to manage 

the ISDRA based on the type of recreation experience that is desired for a specific area

10. How much motorized trespass is occurring in the North Algodones Dunes Wilderness 

Area, what impacts are occurring, and how can it be eliminated?

Motorized vehicles are used to illegally enter the wilderness. Although land use monitoring 

is occurring, the total frequency of trespass is not known. This issue will look at how law 

enforcement and education can reduce the level of trespass.

11. What management actions should be utilized for legal motorized access afforded the 

Border Patrol, California Department of Fish and Game and other law enforcement 

agencies to the North Algodones Dunes Wilderness?

The enabling legislation that designated the North Algodones Dunes Wilderness Area was 

the CDPA. This Act allows for continued motorized use by the California Department of 

Fish and Game to monitor and maintain their wildlife guzzlers inside the wilderness area. 

The CDPA also allows U.S. Border Patrol to continue their operations inside the wilderness 

area. Although these uses are allowed, they have an impact on the wilderness values of 

solitude and naturalness. This RAMP will discuss at what levels these uses would be 

allowed, while accomplishing the goals of all agencies involved.

12. What is the future for the Fee Demo program?

The Fee Demo Program began in the ISDRA on January 1, 1999 as authorized by Congress 

through the BLM’s appropriation process. There has been controversy over the program 

since its inception. Responding to public criticism, the BLM entered into a Memorandum of 

Understanding with the California Department of Parks and Recreation Off-Highway Motor 

Vehicle Recreation Division, and the California Off-Highway Motor Vehicle Recreation 

Commission. This Memorandum of Understanding expired on September 30, 2000. In 

support of this Memorandum of Understanding a technical review team (TRT) was created to 

provide input about how the collected funds should be spent in the ISDRA. 

The 2003 fiscal year Interior appropriations bill extended the Fee Demo test program through 

2004. This is the fifth extension of the original expiration date. It is unknown at this time 

how many more times it will be extended or if it will become permanent legislation. 

Currently, the future of the Fee Demo Program across the U.S., including the ISDRA, 

depends upon the continued re-authorization of this legislation by Congress. 
32

13. How will priorities be set with potential budget reductions from “green sticker” and 

allocated dollars? 

In past years, partnerships with the State of California Off-Highway Vehicle Commission 

and Division have provided a substantial amount of financial support to the ISDRA. Current 

regulations are making those dollars increasingly more difficult to obtain, causing concern 

for future programs at the ISDRA. This issue would address continued financing solutions 

for those programs and projects that are planned.

14. How will potential/partial closure of the ISDRA to recreational use affect OHV users, 

vendors and the communities who base their livelihood and income on OHV activities? 

This issue will explore methods to balance the recreational use of the ISDRA and the 

potential for economic benefit and growth.

15. At what level are noxious weeds occurring within the ISDRA planning area? What 

measures can be taken to reduce or eliminate them?

The area has scattered infestations of salt cedar (Tamarix ramosissima), leafless tamarisk 

(Tamarix aphylla), Sahara mustard (Brassica tournefortii), cheat grass (Bromus tectorum),

and extensive areas of schismus (Schismus barbatus). Infestations of salt cedar occur in the 

pockets of the eastern dunes where water collects after rainstorms. Large leafless tamarisks 

are present north of Highway 78 near Glamis. The east side of the wilderness area contains 

very heavy infestations of Sahara mustard in microphyll woodland, desert dry wash 

woodland and creosote bush scrub habitats. The mustard has also been sighted near the 

Buttercup off-ramp between the freeway and the frontage road. 

Weeds can be eliminated with herbicide applications on a limited scale. Larger scale 

removal is not possible due to the large size of the ISDRA and funding limitations. In the 

future exotic plant removals would focus on areas of high biological value with severe 

infestations. Eradicating exotic plants over the majority of the ISDRA is not a feasible goal. 

In the future, biological controls may become available for some of these species for control 

on a wide scale. However, at this time these methods are not available.

16. How can air quality standards in the ISDRA be met?

The Glamis area has intermittently poor air quality resulting from natural conditions, smog 

and agricultural burning in the nearby Imperial and Mexicali Valleys. The ISDRA Plan Area 

is located within Imperial County, which is a non-attainment area for ozone and PM10. This 

situation is exacerbated on holiday weekends in the fall and winter. At these times, large 

numbers of OHV and motor homes arrive in the Glamis area, creating airborne dust particles 

and hydrocarbon emissions. This issue addresses methods to met air quality standards.

17. Can the loss of OHV opportunities throughout the CDCA plan area be mitigated?
33

Since the inception of the CDCA Plan in 1980, the demand for areas open to OHV 

recreational use has increased. At the same time, other management objectives on BLMmanaged lands have constrained access to some of the areas used historically for OHV 

recreation. (For example, OHV use areas have been closed to protect sensitive biological 

resources. This issue concerns how the BLM can provide OHV and camping opportunities 

to replace lost opportunities at ISDRA and other areas managed by the CDCA plan.

Desired Future Conditions And Management Goals 

In addition to the identification of issues identified by the public, the BLM’s planning 

process included a RAMP Working Group, comprising representatives from the 

environmental and OHV communities, the BLM, and Imperial County staff. This Working 

Group developed a list of desired future conditions to assist planners in identifying goals and 

objectives for the ISDRA during the next 10 to 15 years. The desired future conditions also 

provide the basis for comparing the relative merits of each alternative (see Chapter 2 of this 

EIS). The following summarizes the goals and management objectives that guide the BLM in 

the development of the alternatives and the identification of Alternative 2 as the preferred 

alternative:

- Goal 1 - Provide a variety of sustainable OHV and other recreational activities.

- Goal 2 - Maintain or improve conditions of the special-status species and other 

unique natural and cultural resources.

- Goal 3 - Create an environment to promote the health and safety of visitors, 

employees, and nearby residents by working with local, state, and federal agencies 

and interest groups.

Certain goals and objectives in managing the ISDRA are provided through FLPMA and the 

CDCA Plan. Since its designation, the ISDRA has been managed according to mandates set 

forth in both the 1980 CDCA and 1976 FLPMA. Among FLPMA’s requirements is the 

following:

“the use of all California desert resources can and should be provided for in a 

multiple use and sustained yield management plan to conserve these resources for 

future generations, and to provide present and future use and enjoyment, particularly 

outdoor recreation uses, including the use, where appropriate, of off-road recreational 

vehicles... ” [Title VI. SC1781. Sec. 601 (a)(4)]. 

Authorizing Actions

Prior to implementation of the Preferred Alternative, a Record of Decision (ROD) must be 

issued in accordance with NEPA. A ROD provides a written record explaining why the lead 

agency (BLM) has taken a particular course of action. Issuance of the ROD would allow the 

BLM to move forward in amending the CDCA Plan with an updated recreation area 
34

management plan. The amendment of the CDCA Plan would then allow for implementation 

of the management actions described in the recreation area management plan. 

Other federal agencies with jurisdiction at the ISDRA could also be required to approve the 

Preferred Alternative. As noted above in Section 1.3.8, approval is subject to Section 7 of 

the ESA. Therefore, implementation of a revised recreation management plan is contingent 

upon the issuance of a “No Jeopardy” opinion from USFWS. None of the action alternatives 

is anticipated to affect any waters of the United States under the jurisdiction of the United 

State Army Corps of Engineers (USACE) and, therefore, would not be subject to Section 404 

or 401 of the Clean Water Act. 

Because no discretionary actions are currently required at the state or local level, 

implementing the Preferred Alternative would not require review under the California 

Environmental Quality Act (CEQA). Future management actions associated with 

implementation of a revised RAMP, however, could require approval from state and/or local 

agencies. If it is determined that these actions are subject to CEQA, appropriate 

environmental documentation would be prepared in accordance with the CEQA Guidelines.
35

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CHAPTER 2 

ALTERNATIVES FOR ISDRA MANAGEMENT

Introduction

This chapter presents the NEPA alternatives (including the no action alternative, the 

preferred action, two additional action alternatives, and the alternatives considered but not 

carried forward) that are discussed in this EIS. The alternatives were developed in response 

to the Issues, Concerns, and Opportunities identified through the public scoping process that 

was discussed in the previous chapter.

NEPA requirements (40 CFR 1502.14) direct federal agencies to:

Consider a range of alternatives that could accomplish the lead agency objectives 

(i.e., Purpose and Need) and present the alternatives in comparative form to define the 

issues and provide a clear basis for decision makers and the public to choose among 

options.

Explore rigorously and evaluate objectively a reasonable range of alternatives. If 

alternatives have been eliminated from detailed study, the EIS must briefly discuss 

the reasons they were eliminated. The range of alternatives is project-specific, 

depending on the nature of the proposal and the facts and circumstances of the 

project.

Analyze each alternative to a degree that is substantially similar to the analysis 

afforded the proposed project.

Identify the Environmentally Preferable Alternative from the range of alternatives 

considered. This alternative is typically the scenario that best promotes the 

environmental policy expressed in NEPA.

Include a No Action Alternative. NEPA requires that a No Action Alternative be 

developed and evaluated to allow decision makers to compare the impact of 

approving the Proposed Action with the impacts of not approving the Proposed 

Action.

The alternatives were developed by the BLM on the basis of, and in response to, substantive 

public input on the existing environment, existing uses, desired future uses, and desired 

environmental conditions of the ISDRA. On the basis of this input and in consideration of 

their management obligations under FLPMA and other statutory and policy guidance, the 
38

BLM developed a series of desired future conditions and management goals that are intended 

to apply to a revised RAMP. These conditions and goals also apply to all the alternatives 

considered in this EIS. The goals established by the BLM in the purpose and need for this 

project are consistent with the overall management direction provided to the BLM by the 

various statutes, policies, and guidelines. The alternatives considered in this EIS and 

subjected to analysis are:

Alternative 1: No Action 

The Preferred Alternative: Alternative 2: Recreation and Natural/Cultural Resource 

Protection Alternative

Alternative 3: Natural and Cultural Resource Protection Alternative

Alternative 4: Motorized Recreation Opportunities Alternative

The alternatives analyzed in this EIS, including the No Action Alternative and the 

alternatives considered but eliminated from further analysis are presented later in this 

chapter. The BLM’s Preferred Alternative is Alternative 2.

All the alternatives (with the exception of Alternative 1, No Action) include geographically 

delineated management areas and proposed Recreation Opportunity Spectrum (ROS) 

classifications. The ROS is a system used by many federal and state land management 

agencies to categorize outdoor recreation settings. There are six recreation settings within 

the ROS system, and each setting provides a different set of recreation opportunities and 

experiences. ROS settings range from highly modified environments with numerous contacts 

with other people to undisturbed natural environments with little or no contact with others. 

The ROS classifications and their characteristics are: 

- Urban – Substantially urbanized environment characterizes this setting. Facilities are 

designed and constructed for intensified motor use, including forms of mass 

transportation facilities. Vegetative cover is often exotic and manicured. Sites and 

sounds from humans predominate site and interaction between users is high. 

Overnight camp areas with 0.25 acres per camping party define visitor supply. 

- Rural – A substantially modified natural environment characterizes this setting. 

Resources are modified to enhance specific recreation activities. Sights and sounds 

of humans are readily evident and interaction between users is often moderate to high. 

A considerable number of facilities are designed for use by a large number of people. 

Facilities are often provided for special activities. Facilities for intensified motorized 

use and parking are available. Overnight campsites of 0.25 in the structured pad 

areas to 0.5 acres in the dispersed areas per camping party largely define visitor 

supply of rural ROS settings.

- Roaded Natural – Predominantly natural appearing environments characterize this 

setting. Facilities are designed and constructed to accommodate conventional 
39

motorized use. Moderate sights and sounds of humans exist and interaction between 

users may be low to moderate, but with evidence of other users prevalent. Resource 

modification is evident, but in harmony with the natural environment. Overnight, 

dispersed camp areas with 3 acres per camping party define visitor supply.

- Semi-Primitive Motorized – A semi-primitive motorized area is predominantly 

natural or natural-appearing environment of moderate to large size (generally greater 

than 2,500 acres). The resource integrity of the area is very important to the visitor 

experience. Interaction between users is low, but there is often evidence of other 

users. The area is managed with minimal and subtle on-site controls and restrictions. 

1 overnight camping party for every 10 acres defines visitor supply. 

- Semi-Primitive Non-Motorized – A predominantly natural or natural-appearing 

environment of moderate to large size (generally larger than 2,500 acres) 

characterizes this setting. Interaction between users is low, but there is often 

evidence of other users. The area is managed with minimal and subtle on-site 

controls and restrictions. Motorized use is not permitted. (Note: The configuration, 

size, adjacent highways, railroad and view shed is consistent with semi-primitive 

ROS class, however primitive recreation opportunities are available in some specific 

locations). In semi-primitive non-motorized areas that allow overnight camping, 

visitor supply is defined as 1,280 acres for every overnight camping party.

The goals and management actions, utilizing the ROS classifications, will provide direction 

for land and resource management in the ISDRA.

To manage the desert resources, the CDCA Plan divided all public land within the plan 

boundaries, which includes the ISDRA, into Multiple-Use Classes that stipulate whether 

different areas could be used for motorized recreation, motorized access, and the intensity of 

that use. Because these classes are legally binding, unless amended through the public 

process, the BLM must manage the ISDRA according to the class prescriptions. This EIS 

proposes changes in the Multiple-Use Classes for the three action alternatives; the multipleuse classes for the no action alternative remains the same. All the alternatives (with the 

exception of Alternative 1, No Action) include geographically delineated management areas 

and proposed Recreation Opportunity Spectrum (ROS) classifications. The ROS 

classification system can be used to determine the Multiple Use Class. The ROS 

classifications and their characteristics are: 

Multiple-Use Class I – “Intensive Use”: Its purpose is to provide for concentrated use 

of land and resources to meet human needs. Reasonable protection will be provided 

for sensitive natural and cultural values. Mitigation of impacts on resources will be 

implemented, and rehabilitation of impacted areas will occur, if possible. Recreation 

activities involving high densities are permitted. Campgrounds and other facilities are 

permitted. Lands assigned to Class I incorporate OHV areas within the ISDRA 

designated as “open.” Management areas that are designated as urban or rural are 

under this Multiple-Use Class.
40

Multiple-Use Class M – “Moderate Use”: Based upon a controlled balance between 

higher intensity use and protection of public lands. This class provides for a wide 

variety of present and future uses such as mining, livestock grazing, recreation, 

energy, and utility development. This class is also designed to conserve desert 

resources and to mitigate damage to those resources that permitted uses may cause. 

Recreational use is appropriate at moderate to high densities, and developed 

recreation sites are permitted. Lands assigned to Class M incorporate OHV areas 

within the ISDRA designated as “open.” Identifying individual vehicle routes within 

sand dunes is impractical; therefore, areas assigned Class M are designated as “open” 

whereas they typically would be designated as “limited” by this multiple use class. 

Management areas that are designated as roaded natural are under this Multiple-Use 

Class.

Multiple-Use Class L – “Limited Use”: This class protects sensitive, natural, scenic, 

ecological, and cultural resource values. These lands are managed to provide for 

generally lower intensity, carefully controlled multiple use of resources, while 

ensuring that sensitive values are not significantly diminished. This class is suitable 

for recreation that generally involves low- to moderate-user densities. Developed 

campgrounds or sites involving concentrated recreational use generally are not 

allowed in this class. Lands assigned to Class L incorporate OHV areas within the 

ISDRA designated as “open.” Identifying individual vehicle routes within sand dunes 

is impractical; therefore, areas assigned Class L are designated as “open” whereas 

they typically would be designated as “limited” by this multiple use class. 

Management areas that are designated as semi private motorized are under this 

Multiple-Use Class.

Multiple-Use Class C – “Controlled Use”: There are two purposes to this class: it 

shows areas that are being “preliminarily recommended” as suitable for wilderness 

designation by Congress and it shows those areas formally designated as wilderness 

by Congress. The North Algodones Dunes Wilderness was designated wilderness in 

the CDCA Plan through the California Desert Protection Act of 1994, and is 

designated Class C. Management areas that are designated as semi private nonmotorized are under this Multiple-Use Class.

The goals and management actions, utilizing the Multiple-Use Classifications, will provide 

direction for land and resource management in the ISDRA. A change in the multiple use 

class is a plan amendment.

Alternatives Analyzed In The EIS

Under Alternative 1 (No Action), neither the designation of management areas nor the 

assignment of ROS classes would occur. Under the action alternatives assessed in this EIS 

(Alternatives 2, 3, and 4), the management areas would be applied and the boundaries of the 

management areas would be the same for all the action alternatives. The ROS classifications 

are the key features that would vary among the action alternatives to provide variations in the 

proposed level and management focus of visitor use. The eight management areas in the 

ISDRA and a one-mile area around the ISDRA comprise the ISDRA Planning Area 

evaluated in this EIS. 
41

The one-mile area around the ISDRA is actually managed in two other BLM plans: the 

Northern and Eastern Colorado Desert Coordinated Management Plan (NECO) and the 

Western and Eastern Colorado Desert Route of Travel Plan (WECO ROT). It is not a part of 

the ISDRA. These plans have designated the routes that may be used in this one-mile area 

that is around the ISDRA. These plans also require that all travel in this one-mile area must 

be on a route that is designated as open or limited use. The only action that the ISDRA EIS 

will propose for the one-mile wide area managed by NECO and WECO ROT is a no 

camping consideration. The ISDRA EIS record of decision will determine the camping 

decision for this area. This one-mile area around the ISDRA will be referred to as the 

“Planning Area” throughout this EIS and the RAMP.

Alternative 1: No Action Alternative

Under Alternative 1, the ISDRA would continue to be managed according to the existing and 

approved management plan and policies (e.g., the 1987 RAMP). In addition, the No Action 

Alternative would include compliance with policies and management measures instituted 

since the 1987 RAMP was first implemented, including the designation of the North 

Algodones Dunes Wilderness in 1994 and the release of Wilderness Study Area 362 from 

further suitability studies. Alternative 1 does not include any of the actions that were 

proposed in the 1987 RAMP and were not implemented prior to 2002 because management 

must also accommodate the findings of more recent resource inventories at the ISDRA, as 

well as updated regulations that could constrain full implementation (e.g., new facilities 

would not be allowed in the wilderness area). Under this alternative, the ROS classifications 

and management areas that apply to the action alternatives will not be created. See Figure 2-

1. Also, Alternative 1 does not include the interim OHV closure areas or the temporary 

camping closure because these are temporary measures and not part of the management 

policy for the ISDRA. Vendor locations are shown in Figure 2-2.

This alternative continues the current management of the Planning Area, without considering 

the recent and proposed plan amendments for this area. The CDCA Plan would not be 

amended under this alternative, and no adaptive management program would be 

implemented. Multiple use classes and vehicle use classes would remain the same as in the 

1987 RAMP.
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View Figure 2-1

Alternative 1-no action - 62KB 

 
44

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View Figure 2-2

Map of vendor locations for Alternative 1 no action - 46Kb
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47

Actions Common to the Action Alternatives (Alternatives 2 -4)

This section summarizes the overall management actions proposed by the BLM that would 

pertain to all the action alternatives (Alternatives 2, 3, and 4) analyzed in this EIS. Eight 

management areas would be created within the ISDRA and one area of consideration (the 

Planning Area) external to the ISDRA boundary. These management areas, listed below, 

would be the same geographical areas under each of the three action alternatives. Each 

management area would be assigned a specific ROS classification and multiple use 

classification that would guide permitted activities, level of development, type of recreational 

experience, and assist the BLM to establish planning goals for visitor use in the different 

management areas. The ROS classifications vary among the alternatives. These 

management areas would be:

Mammoth Wash Management Area

North Algodones Dunes Wilderness Management Area

Gecko Management Area 

Glamis Management Area

Adaptive Management Area

Ogilby Management Area

Dune Buggy Flats Management Area

Buttercup Management Area

The area of consideration is the:

Planning Area

The Planning Area will not be assigned a ROS classification, nor will its activities be 

managed under the ISDRA Management Plan. The Planning Area is not a part of the 

ISDRA: it never was a part of the ISDRA. It is an area that surrounds the ISDRA and is used 

in planning documents to analyze off-site effects on the surrounding area. 

A summary of the management actions that pertain to all the action alternatives (for all the 

management areas) is presented in the table below.

 MANAGEMENT ACTIONS 

(APPLICABLE TO ALL MANAGEMENT AREAS FOR ALTERNATIVES 2, 

3, AND 4)

Recreation Maintain and manage ISDRA as a unique locale providing urban, 

 rural, roaded-natural, or semi-primitive OHV recreation

 opportunities in the desert Southwest.

Compensate recreation area loss by increasing recreation

 opportunities in other areas within the planning boundary.
48

 MANAGEMENT ACTIONS 

(APPLICABLE TO ALL MANAGEMENT AREAS FOR ALTERNATIVES 2, 

3, AND 4)

Public 

Outreach

Develop a public relations program on cultural and natural

 resources; safety; hazardous and solid wastes; interpretive 

 displays and brochures.

Biological 

Resources

Manage using principles of adaptive management. Adaptive

 management is a process of implementing policy decisions as

 scientifically driven management experiments that test

 predictions and assumptions in management plans, using the

 resulting information to improve the plans. 

Reduce impacts to natural resource areas that are outside of

 ISDRA through posting of designated routes, education, and

 enforcement.

Utilize existing laws to protect special species, as needed. 43 CFR

 8341.2 states that where the authorized officer determines that

 off-road vehicles are causing or will cause considerable adverse

 effects upon soil vegetation, wildlife, wildlife habitat, cultural 

 resources, historical resources, threatened or endangered

 species, wilderness suitability, other authorized uses, or other

 resources, the authorized officer shall immediately close the

 area affected to the type(s) of vehicle causing the adverse effect

 until the adverse effects are eliminated and measures

 implemented to prevent reoccurrence. 

Air Quality Implement dust control measures on wash roads and at the

 entrance to Dune Buggy Flats.

Transportation 

Traffic

Grade roads, implement fee entry and construct traffic control 

Public Safety Create a law enforcement cooperative team.

Increase permanent staff and holiday staff to address the increases

 in visitor use of major holidays.

Continue a Zero Tolerance Policy toward assaults, alcohol and

 drug abuse and other serious violations. 

Include the ability to ban alcohol outside camping areas if other

 law enforcement tools are unable to adequately promote a safe

 environment. Visitor use and incident data will be monitored

 and will be used to evaluate the need for this tool and to develop
49

 MANAGEMENT ACTIONS 

(APPLICABLE TO ALL MANAGEMENT AREAS FOR ALTERNATIVES 2, 

3, AND 4)

 the criteria for its use.

Establish a law enforcement tool to allow closures and restrictions

 at Competition Hill north and south, Oldsmobile Hill, Test Hill, 

 Patton Valley, the sand drags and other areas as needed to

 encourage law and order. Visitor use and incident data will be

 monitored and will be used to evaluate the need for this tool and

 to develop the criteria for its use.

The sand drags will receive additional law enforcement attention.

 Current rules such as those relating to reckless driving, speed

 limits near other users, and driving under the influence of

 alcohol, will be aggressively used to promote a safer

 environment.

Post speed limits.

Develop and maintain radio communication system.

Upgrade facilities to include law enforcement, medical, visitor 

services and dispatching duties from Cahuilla

 Ranger Station.

Visitor Use Establish ROS classifications and visitor use targets for

 management areas.

Manage ISDRA use if visitation exceeds proposed ROS

 classifications for a specific number of days by following

 certain processes.

Social and 

Economics

Add free use days from the Saturday of the first full weekend in

 December to the following Friday to accommodate visitors that

 may find that the fees present an economic hardship. The free

 days are free to all users. 

Land Use Establish management areas with specific ROS classifications to

 meet planning objectives.

Provide coordination with adjacent land use plans to control

 impacts to these areas from ISDRA users.

Commercial Vending would continue to be 7 days a week at long term vending

 areas. (Specific locations, if any, change based on the 

 alternative.)

Vending would be permitted from October 1 through May 31 from 
50

 MANAGEMENT ACTIONS 

(APPLICABLE TO ALL MANAGEMENT AREAS FOR ALTERNATIVES 2, 

3, AND 4)

noon Thursday through noon Monday at the short term vending

 areas. (Specific locations change based on the alternative.) All

 vending materials, supplies and related vending material would

 be required to be physically removed from the ISDRA from

 Monday at noon to Thursday at noon.

Do not routinely allow non-recreational commercial activities 

 (such as filming) during the high use holiday periods.

Access and 

Facilities 

Development

Develop or retrofit facilities, in the appropriate ROS classes, to

 accommodate visitation and meet all disability regulations and

 standards.

Ensure that little or no development occurs in primitive areas.

Construct disability and tortoise compliant trash collection

 facilities and loading docks.

Fiscal Collect fees in all areas based on demand and cost recovery.

Move toward the ISDRA becoming more independent from 

appropriations and grants.

Review price structure every 2 years.

Update fee business plan within 2 years of the record of decision

 for the EIS being signed.

Plan 

Amendment

The CDCA Plan would be amended to reflect the multiple use and 

vehicle use classifications for each alternative. It would also be 

amended to reflect adaptive management of the proposed adaptive 

management area, the visitor supply (based on the number of 

vehicles), and the allocation of commercial activities. The CDCA 

Plan would be amended to expand the size of the ISDRA by 

approximately 1200 acres.

Alternative 2: Recreation and Natural/Cultural Resource Protection Alternative 

Under Alternative 2, the actions identified above would be adopted. Each of the 

management areas would also be assigned the following specific ROS classification, vehicle 

use class and multiple use class that would be used to guide future visitor use and other 

management decisions such as the level of facility construction: 
51

ROS

See Figure 2-3

Vehicle Use Class Multiple Use Class

See Figure 2-4

Mammoth Wash Semi-Primitive 

Motorized

Open Limited

North Algodones 

Dunes Wilderness

Semi-Primitive NonMotorizedClosed Controlled

Gecko Rural Open Intensive

Glamis Roaded Natural Open Moderate

Adaptive Semi-Primitive 

Motorized

Limited, except for 

areas used for 

controls in the 

monitoring program, 

which are Closed. 

Please see the 

Monitoring Plan for 

more information.

Limited

Ogilby Roaded Natural Open Moderate

Dune Buggy Flats Roaded Natural Open Moderate

Buttercup Rural Open Intensive

The management focus for Alternative 2 would be to ensure continued use of the ISDRA for 

OHV recreational opportunities, consistent with its designation as a Recreation Area, and to 

provide for the protection of natural and cultural resources. 

Beginning in October 2003, the Gecko Road vending pad would be the designated long term 

vending pad. Vending on this pad will be allowed continuously throughout the duning 

season. That is, vending would continue to be 7 days a week in this area.

The short term vending locations for this alternative would be located at Buttercup, Dune 

Buggy and Glamis. Commercial services would include an increase in the number of days a 

vendor could operate at a short term vending location at the ISDRA. Vending would be 

expanded to include seven days a week vending from noon on December 25 through noon on 

the Monday following January 1. Vending would also be expanded to include the seven days 

prior to Easter. Vending would be allowed on all observed federal holidays. (If the observed 

federal holiday falls on a Friday, vending would be allowed from noon on the Thursday prior 

to the holiday and continue through the weekend to noon on Monday. If the observed federal 

holiday falls on a Monday, vending could continue from the previous Friday, at noon, 

through the weekend to Tuesday at noon.) Vending would be allowed from noon the 

Thursday before Thanksgiving to noon the Monday following Thanksgiving. Vendor 

locations are shown in Figure 2-5.

Alternative 2 also includes the construction of a new law enforcement and educational 

facility at the location of the current ranger station, Cahuilla, and a permanent law 

enforcement and educational facility at Buttercup. The construction of these two facilities 

will restrict overnight camping from within 50 feet of the facilities.
52

A key component of alternatives 2 and 4 is the implementation of an adaptive management 

strategy coupled with biological resources monitoring of the Adaptive Management Area. 

The Adaptive Management Area would be open from dawn to dusk during October 15 to 

March 31 of each year and closed to vehicles from April 1 through October 14. The adaptive 

management and monitoring program would include the development of a monitoring plan 

and analysis of the monitoring results to determine the impacts (if any) to species of concern 

as a result of recreational use of the ISDRA. Management of recreational use, especially in 

the Adaptive Management Area, would be evaluated periodically and the level of use would 

be revised as needed to achieve a balance of providing motorized recreational opportunities 

and conserving species of concern. The special-status plant species to be monitored would 

be Peirson’s milk-vetch (Astragalus magdalenae var . peirsonii), Algodones Dunes 

sunflower (Helianthus niveus ssp. tephrodes), and sand food (Pholisma sonorae). A BLM 

sensitive species, the Colorado Desert Fringed Toed Lizard (uma notata notata) will also be 

monitored. Monitoring and surveys would also occur for recruitment of microphyll species, 

cover and birds, as funding is available. Aerial monitoring of OHV use patterns will 

continue for the ISDRA. OHV use would be estimated using permit data, fee data and 

survey information. The data from biological monitoring and OHV estimated use would be 

used to develop management actions. Please see Appendix A for a copy of the proposed 

monitoring plan.

In addition, alternatives 2 and 4 would allow access to the Adaptive Management Area via 

permit only; and those entering the area would be required to participate in a resource 

conservation program. This program would be required for all drivers of OHVs and for each 

person entering the area by foot. The program will allow for accommodations for children 

and disabled individuals. Certification by the participants would document that they have 

completed and understand the environmental program. No facilities would be allowed in this 

area, and interpretive signs would be provided to educate OHV users about the sensitive 

natural and cultural resources in that area. 

Visitor use in the Adaptive Management Area would be limited to 75 OHV groups (defined 

as up to 7 vehicles per OHV group) per day (a maximum of 525vehicles per day), for the 

first year of implementation. This visitor supply will be adjusted after collecting data for 

three years, as required by the monitoring data. After the initial three years, adjustments to 

the permitted number of groups may be made on a yearly basis (increased or decreased) if the 

analysis indicates adjustments can be made at that frequency. During the first three years 

the number of non-OHV users will also be monitored in order to determine what the demand 

is for this area. Monitoring of the number of non-OHV users will continue on a yearly basis 

until a visitor supply for this population is determined.

Among the action alternatives (2, 3, and 4), this alternative is anticipated to result in the 

greatest likelihood of meeting the project purpose, need and goals. It is the alternative that 

best balances the conflicting goals of resource conservation and recreational use. Therefore, 

Alternative 2 is considered the Preferred Alternative by BLM. Alternative 2 is shown in 

Figures 2-3 and 2-5.
53

View Figure 2-3

Alternative 2 ROS from draft EIS - 89Kb 
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View Figure 2-4

Alternative 2 MUC - 74Kb
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View Figure 2-5

Alternative 2 - Vendor locations - 66Kb 
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Alternative 3: Natural and Cultur al Resources Protection Alternative

Under Alternative 3, the actions identified as common to all action alternatives would be 

adopted. Each of the management areas would also be assigned the following specific ROS 

classification that would be used to guide future visitor use and other management decisions 

(e.g., levels of facilities construction, law enforcement): 

ROS

See Figure 2-6

Vehicle Use Class Multiple Use Class

See Figure 2-7

Mammoth Wash Semi-Primitive NonMotorizedClosed Controlled

North Algodones 

Dunes Wilderness

Semi-Primitive NonMotorizedClosed Controlled

Gecko Roaded Natural Open Moderate

Glamis Semi-Primitive 

Motorized

Open Limited

Adaptive Semi-Primitive NonMotorizedClosed Controlled

Ogilby Semi-Primitive 

Motorized

Open Limited

Dune Buggy Flats Semi-Primitive 

Motorized

Open Limited

Buttercup Roaded Natural Open Moderate

The semi-primitive non-motorized ROS classification of the Mammoth Wash, Adaptive, and 

North Algodones Dunes Wilderness Management Areas excludes OHV recreational 

activities in those areas. Law enforcement vehicles and staff, however, would be exempt 

from this prohibition. The ROS classification of semi-primitive non-motorized in the 

Adaptive Management Area would close this area to motorized recreation activity. 

Therefore, permits and environmental programs addressing the unique species in the central 

dunes would not be required because vehicular access would not be allowed. Alternative 3 is 

shown in Figures 2-6 and 2-7.

Alternative 3 would effectively provide a higher level and more immediate focus on natural 

and cultural resources in the ISDRA through the application of management actions that 

would reduce OHV use. Monitoring would still occur under Alternative 3, but no adaptive 

management program permitting OHV use would be implemented during the life of this 

Management Plan. Because the Adaptive and Mammoth Wash Management Areas would 

have the same ROS category as the North Algodones Dunes Wilderness Management Area 

(semi-primitive non-motorized), similar management objectives and actions would apply. 

This would create uniformity of management direction over a larger area.

Signing and public information would be provided to inform OHV users of the motorized use 

restrictions in the Mammoth Wash, North Algodones Dunes Wilderness, and Adaptive 

Management Area to minimize the potential for incidental trespass. In addition, an increase 
60

in the number of law enforcement staff would be included as a management action. The 

closure of the Mammoth Wash and Adaptive Management Areas to motorized recreation 

activity would provide the greatest level of assurance that sensitive natural and cultural 

resources would remain protected. 

However, managing approximately 67,596 acres in the semi-primitive non-motorized ROS 

category would reduce the total area available to OHV activity at the ISDRA, and within the 

California Desert as a whole, by that number of acres. However, this would allow 

approximately 42 percent of the ISDRA to be managed mainly for its natural and cultural 

resource values. In addition, the total number of recreational users that could be 

accommodated in the ISDRA would be reduced under this alternative as compared to the 

proposed alternative due to the ROS classifications that are assigned to the management 

areas. No additional law enforcement facilities would be built.

A new ranger station would be placed at Osborne Outlook. However, the main focus of this 

facility would be public education, rather than law enforcement. A new ranger facility would 

not be developed in the Buttercup area. The temporary ranger station would continue to be 

utilized at Buttercup.

This alternative would allow short term vending from October 1 through May 31 from noon 

Thursday through noon Monday at the Gecko, Glamis, Buttercup and Dune Buggy Vendor 

Pads. This alternative does not provide a long term vendor area. Vendor locations are shown 

in Figure 2-8.
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View Figure 2-6

Alternative 3 ROS from draft EIS - 90Kb
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View figure 2-7

Alternative 3 MUC - 74Kb
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View figure 2-8

Vendor locations Alternative 3 - 63Kb 
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Alternative 4: Motorized Recreation Opportunities Alternative

Under this alternative, the management actions for the ISDRA would be responsive to public 

input that emphasizes a need for maximal motorized recreational opportunities. Therefore, 

management measures would be directed at allowing an increased intensity of OHV activity. 

The increased intensity of use facilitated by Alternative 4 would serve to accommodate 

existing and future OHV recreational demand at ISDRA by increasing the overall visitor 

supply, as well as by shifting the areas of use. In addition, Alternative 4 would provide an 

altered type of recreation experience at the ISDRA by adding an urban recreational 

opportunity (greater densities would be allowed for camping compared with the other 

alternatives).

Under Alternative 4, the actions identified as common to all alternatives would be 

implemented. Each of the management areas would also be assigned the following specific 

ROS classification that would be used to guide future visitor use and other management 

decisions (e.g., levels of facilities construction, law enforcement): 

ROS

See Figure 2-9

Vehicle Use Class Multiple Use Class

See Figure 2-10

Mammoth Wash Roaded Natural Open Moderate

North Algodones 

Dunes Wilderness

Semi-Primitive NonMotorizedClosed Controlled

Gecko Urban Open Intensive

Glamis Rural Open Intensive

Adaptive Roaded Natural Limited, except for 

areas used for 

controls in the 

monitoring program, 

which are Closed. 

Please see the 

Monitoring Plan for 

more information.

Moderate

Ogilby Rural Open Intensive

Dune Buggy Flats Rural Open Intensive

Buttercup Urban Open Intensive

The ROS classifications assigned to most proposed management areas would be consistent 

with a desired moderate-to-high level of OHV recreational use. The ROS for the Adaptive 

Management Area would be roaded natural. Limited facilities may be developed under this 

classification in the Adaptive Management Area. The monitoring and adaptive use of this 

area as described in alternative 2 would be implemented. The classification for the Glamis 

Management Area would be rural. Future management actions could include facilities to 

accommodate increased visitation such as new campgrounds, camping pads, toilets, trash 

stations, and information kiosks. 
68

Under this alternative, vending would be allowed from October through the end of May, 

seven days a week at three long term vendor areas: Buttercup, Dune Buggy Flats and on 

Gecko Road. Glamis would be a short-term vendor area. Vendor locations are shown in 

Figure 2-11.

Commercial services would include an increase of the number of days a short-term vendor 

could operate at the ISDRA. Vending would be expanded to include seven days a week 

vending from noon on December 25 through noon on the Monday following January 1. 

Vending would also be expanded to include the seven days prior to Easter. Vending would 

be allowed on all observed federal holidays. (If the observed federal holiday falls on a 

Friday, vending would be allowed from noon on the Thursday prior to the holiday and 

continue through the weekend to noon on Monday. If the observed federal holiday falls on a 

Monday, vending could continue from the previous Friday, at noon, through the weekend to 

Tuesday at noon.) Vending would be allowed from noon the Thursday before Thanksgiving 

to noon the Monday following Thanksgiving. 

Permanent law enforcement and educational facilities would be developed in Buttercup. The 

current Cahuilla Ranger Station would be expanded to meet the law enforcement needs in the 

Glamis area. Alternative 4 is shown in Figures 2-9 and 2-10. 
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View Figure 2-9

Alternative 4 ROS - 82Kb
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View Figure 2-10

Alternative 4 MUC - 78Kb
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View Figure 2-11

Altenative 4 Vendor Locations - 63Kb 
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Alternatives Considered But Eliminated

This section presents the alternatives that were initially considered for analysis in this EIS but 

eliminated from further detailed consideration. Overall, the primary reason that they were 

not carried forward for detailed analysis is that they would not meet the purpose and need of 

the BLM’s proposed action. Although these alternatives are not evaluated in detail, issues of 

concern raised by the public in the scoping meetings and in other forums are included in 

several of the alternatives.

 

Hybrid Recreation Intensive Alternative

The Hybrid Recreation Intensive Alternative would open the majority of the ISDRA to 

motorized and non-motorized recreational opportunities with the exception of the Wilderness 

Area and certain closed areas. The Hybrid Recreation Intensive Alternative would:

Implement several northwest-southeast trending permanent closure areas for resource 

protection along the western dune boundary. OHV corridors, associated with 

Coachella Canal drop bridges, allowing motorized access to the interior dunes, would 

traverse these closures at periodic locations.

Establish a single larger east-west closure for resource protection traversed by two 

north-south OHV corridors.

Install fencing along naturally occurring valleys at the base of dunes to increase 

compliance and decrease maintenance.

Rationale for Rejection: The primary reason for rejection of this alternative is that it 

does not meet the purpose and need to maintain habitat requirements for specialstatus species. Specifically, habitat fragmentation would result from implementation 

of this alternative. Although this alternative provides for closure of certain areas of 

the ISDRA to OHV use, these closures would fragment existing sensitive species 

populations by allowing multiple areas at which to traverse the dunes by motorized 

vehicles. Also, it does not provide a process to allow the maximum recreational use 

of the ISDRA while maintaining the unique and diverse habitat of the dunes system. 

Total Closure Alternative

The Total Closure Alternative would implement a complete exclusion of OHV use in the 

ISDRA with the intent of maximizing natural and cultural resource protection. 

The Total Closure Alternative would be defined by the following characteristics: 

The entirety of the ISDRA would be closed to motorized recreational opportunities.
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Existing road access to the ISDRA would be maintained, but roads would not be 

expanded/improved.

Existing campsites would be retained, but campsites would not be added or improved. 

Permits for vending opportunities would not be issued.

Natural resource monitoring would not occur and inventories of plant, wildlife, and 

cultural resource inventories would not be conducted.

Rationale for Rejection: The primary reason for rejecting this alternative is that it does not 

meet the purpose and need for the action contemplated by the BLM. Specifically, a total 

closure alternative would not: 

Conform to the CDPA intent to provide for continued OHV use at the ISDRA. 

Provide a process to allow the maximum recreational use of the ISDRA while 

maintaining the unique and diverse habitat of the dunes system. 

Provide the opportunity for OHV recreational activities in accordance with the intent 

of the CDCA Plan. (The CDCA Plan specifically designates the ISDRA as an open 

area for OHVs and the ISDRA has been managed for this use since the early 1970s.)

Meet the BLM’s specific goals for the actions evaluated in this EIS (i.e., provide a 

variety of sustainable OHV and other recreational activities).

Identify the type and level of visitor services, including facilities, needed to support 

desired visitor use.

Institute measures to achieve desired visitor use levels or accommodate service 

providers in the ISDRA. 

In addition, total closure of the ISDRA is not required to ensure protection of 

sensitive species at the ISDRA. Measures for protection of these resources are 

incorporated into several of the alternatives considered in detail in this EIS.

Interim Management Alternative

Under the Interim Management Alternative, the ISDRA would continue to be managed 

according to the existing and approved management plan and policies (i.e., the 1987 RAMP). 

This alternative would include policies implemented since the 1987 RAMP, including 

designation of the North Algodones Sand Dunes Wilderness in 1994, and release of WSA 

362 from further studies to determine suitability for wilderness designation. In addition, this 

alternative would include the recent interim closures and actions of the negotiated settlement 

agreement that stipulate interim temporary closure of certain areas at the ISDRA (i.e., those
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measures taken to provide protection for endangered and threatened species). Characteristics 

of the Interim Management Alternative include the following:

No adaptive management of ISDRA

Permanent Northern Closure (approximately 3,802 acres), located just south of 

Mammoth Wash

Permanent Central Closure Number 1 (approximately 2,000 acres), located east of 

Gecko Road

Permanent Central Closure Number 2 (approximately 43,345 acres), located in the 

center of the Glamis/Gecko area

Permanent Patton Valley Closure (approximately 310 acres), located near Patton 

Valley

Permanent Southern Closure (approximately 160 acres), located south of I-8 in the 

northwestern portion of Buttercup

Permanent closure of Eastern Area, non-critical, Class III, desert tortoise habitat to 

camping (approximately 25,600 acres) 

Rationale for Rejection: The primary reason for rejecting this alternative is that interim 

closures (as stipulated in the settlement agreement) do not meet the purpose and need for the 

action. Specifically, this alternative would not:

Provide a process to allow the maximum recreational use of the ISDRA while 

maintaining the unique and diverse habitat of the dunes system. 

Develop a large continuous geographical area for habitat and species conservation. 

This area will include all of the habitat types that are present in the dunes system. 

Although the large central closure could meet this need, the other smaller closures 

would not meet this need and would be in conflict with the need that these acres are

continuous and that the habitat is not fragmented. The additional fragmented and 

discontinuous acres would unnecessarily result in a lower number of available acres 

for recreational use, which would be in conflict with the recreational need statement.

Allow the closed geographical areas to be available for OHV and other recreational 

uses or for the recreational use of the area to be adjusted as needed to conserve the 

habitat and species.

Utilize sound science when making decisions concerning species conservation and 

multiple use of the ISDRA.
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These closures were not developed using sound science and information we now have 

available. We now know that these closures are not required for adequate protection of 

sensitive species. A settlement agreement was developed in November 2000 with plaintiffs 

(Center for Biological Diversity and others) to establish interim actions to protect endangered 

and threatened species pending completion of USFWS consultation on the CDCA Plan in 

total. Prior to November 2, 2000, the BLM did not have the results of monitoring to assess 

adequately the status of sensitive species addressed by the settlement agreement. The results 

of the monitoring conducted since November 2000 and other data collected prior to 

November 2000 and assessed after the settlement agreement indicate that continuing the 

interim closures is not necessary to ensure adequate protection for the species of concern. 
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CHAPTER 3

Affected Environment

Introduction

This chapter presents a description of the affected environment for the Plan Area and 

vicinity. It is organized into the following resource categories:

- Recreation (Section 3.1)

- Biological Resources (Section 3.2)

- Law Enforcement and Public Safety (Section 3.3)

- Social (Section 3.4)

- Economics (Section 3.5)

- Land Use and Land Ownership (Section 3.6)

- Visual Resources (Section 3.7)

- Water Resources (Section 3.8)

- Cultural Resources (Section 3.9)

- Transportation and Traffic (Section 3.10)

- Noise (Section 3.11)

- Air Quality (Section 3.12)

- Hazardous Materials (Section 3.13)

- Geology, Energy, and Mineral Resources (Section 3.14)

For the purpose of preparing the analysis provided in Chapter 4 of this EIS, the baseline 

affected environment is defined as those conditions that existed prior to implementation of 

the temporary OHV and camping closures, referred to as “Current Conditions” (see Chapter 

1). The last full recreation season at ISDRA in which these conditions occurred was 

October 1, 1999 to September 30, 2000. During this time period, management activities at 

ISDRA were conducted in accordance with the 1987 RAMP. 

The Imperial Sand Dune system is divided into three main areas. The northernmost area is 

known as Mammoth Wash. South of Mammoth Wash and north of SR-78 is the North 

Algodones Dunes Wilderness, a 26,202-acre wilderness area established by the 1994 CDPA. 

This area is closed permanently to OHVs and other mechanized use, with hiking and 

horseback access permitted. The largest and most heavily used OHV area is located south of 

SR-78, and continues south past I-8. 

Areas within the ISDRA currently designated for OHV use by the CDCA Plan and the 1987 

RAMP include:

- That portion of Mammoth Wash located north of the North Algodones Dunes Wilderness
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- The Glamis/Gecko area, located just south of SR-78

- Dune Buggy Flats and Ogilby located in the southern portion of ISDRA

- Buttercup, located south of I-8, near the border of Mexico

The following sections provide further detail on the baseline conditions at ISDRA, based on 

14 distinct but interrelated resource categories.
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3.1 Recreational Resources

Overview

The Imperial Sand Dunes Recreation Area, commonly called (Algodones Dunes or Glamis), 

is the premiere and most visited OHV recreation area in the California Desert Conservation 

Area. It is also considered the premiere sand dune OHV recreation area in the Nation due to 

the outstanding and expansive opportunities. In addition, the ISDRA provides unique habitat 

for several endemic and sensitive plant, insect and animal species. 

The ISDRA is located in Imperial County, California approximately 25 miles west of the 

Colorado River and immediately north of the border between the United States and Mexico. 

Primarily State Route 78 and Interstate 8 provide access to the Imperial Sand Dunes. The 

City of Brawley is located 25 miles to the west, the City of El Centro 40 miles southwest, and 

the city of Yuma, AZ is 15 miles to the east. The Dunes contain several open areas as well as 

a congressionally designated wilderness area.

The Mammoth Wash “open” area is the most remote OHV area within the ISDRA due to its 

northern location within the ISDRA. The Mammoth Wash “open” area is about five miles 

long and two miles wide and is accessed by the Glamis-Niland gravel county road. The 

distance from the pavement to the staging area is approximately 13 miles. Visitation is 

usually 0 to 5 campers with weekend and holiday visitation peaking at about 40 primary 

vehicles. Visitors to this area enjoy the remote location away from the intensively utilized 

areas of the ISDRA. On weekends during the use season (October-May), visitors tend to be 

residents from the nearby communities of Niland and Calipatria.

The North Algodones Dunes Wilderness is located between the Mammoth Wash “open” area 

and State Highway 78. A Watchable Wildlife site is conveniently located on the GlamisNiland Road, two miles north of Highway 78. The site provides interpretive displays on the 

wildlife and habitat of the Algodones Dunes and provides an excellent staging area for hikes 

and school field trips. Hikers into the wilderness can observe many indigenous plant and 

animal species such as the Pierson’s milk-vetch (Astragalus magdalenae var. peirsonii), 

fringe-toed lizard, mule deer and other desert animals.

The Glamis / Gecko Area just south of Highway 78 is the most intensively utilized OHV area 

within the ISDRA. Gecko Road is the most developed area with numerous developed 

campgrounds and other facilities. Located along Gecko Road is Cahuilla Ranger Station, the 

headquarters for ISDRA and incident command center for dunes operations. Dispatch 

services and most of the personnel are based out of the Station. Other facilities along Gecko 

Road include: Gecko Campground; Keyhole Campground; Roadrunner Campground; six 

hardened camping pads; a vendor area; vault toilets; trash facilities; self-pay fee stations; 

kiosks; and a public telephone.

The Glamis Area (eastside) is undeveloped with minimal facilities and provides for open 

desert camping. The main access into the Glamis Area is via the Wash Road adjacent to the 
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Union Pacific (formerly Southern Pacific Rail Road). The improved Wash Road allows for 

safe and easy access to the camping area known as the “washes”. The Glamis and Garbage 

Flats areas are open desert camping areas accessed from Highway 78. The BLM provides 

trash facilities, law enforcement, emergency medical services, and holiday toilet facilities, 

through a combination of fee demonstration project, appropriated (tax), and California State 

Parks Off-highway Vehicle Motor Vehicle grant funding. The town of Glamis is privately 

owned and supports three OHV oriented businesses. There is also the small settlement of 

Boardmanville just east of “Wash 10” south east of Glamis.

The Dune Buggy Flats area is located in the southern portion of the ISDRA and is located 

north of Interstate 8. The main access into the area is via the Gordon’s Well exit off Interstate 

8 and an improved dirt road. This is an intensive OHV area similar to the Glamis / Gecko 

area. Facilities located within this area include: kiosks, signs, trash facilities, self -pay fee 

stations; and a portable ranger station trailer staffed by BLM staff on holiday weekends.

The area west of the Coachella Canal and adjacent Gordons Well Road was closed (March 

2002) to camping in order to protect the flat-tailed horned lizard (Phrynosoma mcalli) and its 

habitat. The closure was the result of a Biological Opinion that mitigates impacts of the 

Herman Schneider Memorial Bridge. The bridge opened in April 2001 and provides OHV 

access across the All American Canal and the shared use (OHV and Street-legal vehicles) of 

the Gordons Well overpass. This allows OHV enthusiasts legal access across Interstate 8 

from the Buttercup Valley to the Dune Buggy Flats area. Prior to the bridge construction, 

there were illegal and dangerous OHV crossings across Interstate 8. The land east of and 

adjacent to the closed area is privately owned and supports an OHV oriented private 

business.

Located in the southeastern area of the ISDRA is the Ogilby Camp area. The access to this 

area is via the Ogilby Road and a dirt/sand road. This area is similar to Mammoth Wash and 

has a fee machine but no other facilities, or services, except irregular BLM patrols. Visitation 

is low to moderate with most use on weekends and holidays.

The Buttercup Area is located south of Interstate 8 and north of the international border with 

Mexico. The Grays Well Road provides access to Buttercup, Midway, and the Plank Road 

camping areas. All three camping areas have vault toilets, and trash facilities. The Plank 

Road provides visitors a chance to observe an interesting part of California history. A metal 

protective barrier and interpretive signs surround the last remnants of the old wooden road 

that enabled vehicles to cross the Dunes in 1915. These areas are all within a 20-minute 

drive to Yuma, AZ, where there are shops and a hospital. The Mexico border town of 

Algodones is also nearby. Visitors can drive street vehicles, park, and then walk across the 

border to shop and eat. 

OHV opportunities near the Dunes are limited to existing trails and routes. There is a 

network of trails east of the Dunes that extend to the Colorado River and north to Interstate 

10. There are several Wilderness Areas and military closurses that limit access to several 

areas. There is very little OHV opportunity directly west of the Dunes in the East Mesa. The 

cities of Brawley, Imperial, Holtville, and El Centro lie west of the East Mesa. On the far
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western side of the valley lie the Ocotillo Wells State Vehicle Recreation Area, Plaster City 

and Superstition Mountains. These are open areas with limited use areas around them.

Center for Biological Diversity v. Bureau of Land Management

On March 16, 2000, the Center for Biological Diversity, and others (Center) filed for 

injunctive relief in U.S. District Court, Northern District of California (court) against the 

Bureau of Land Management (BLM) alleging that the BLM was in violation of Section 7 of 

the Endangered Species Act (ESA) by failing to enter into formal consultation with the U.S. 

Fish and Wildlife Service (FWS) on the effects of adoption of the CDCA Plan, as amended, 

upon threatened and endangered species. On August 25, 2000, the BLM acknowledged 

through a court stipulation that activities authorized, permitted, or allowed under CDCA Plan 

may adversely affect threatened and endangered species, and that the BLM is required to 

consult with the FWS to insure that adoption and implementation of the CDCA Plan is not 

likely to jeopardize the continued existence of threatened and endangered species or to result 

in the destruction or adverse modification of critical habitat of listed species. 

Although BLM has received biological opinions on selected activities, consultation on the 

overall CDCA Plan is necessary to address the cumulative effects of all the activities 

authorized by the CDCA Plan. Consultation on the overall Plan is complex and the 

completion date was uncertain. Absent consultation on the entire Plan, the impacts of 

individual activities, when added together with the impacts of other activities in the desert are 

not known. The BLM entered into negotiations with plaintiffs regarding interim actions to 

be taken to provide protection for endangered and threatened species pending completion of 

the consultation on the CDCA Plan. Agreement on these interim actions avoided litigation of 

plaintiffs’ request for injunctive relief and the threat of an injunction prohibiting all activities 

authorized under the Plan. These interim agreements have allowed BLM to continue to 

authorize appropriate levels of activities throughout the planning area during the lengthy 

consultation process while providing appropriate protection to the desert tortoise and other 

listed species in the short term. By taking interim actions as allowed under 43 CFR Part 

8364.1, BLM contributes to the conservation of endangered and threatened species in 

accordance with 7 (a) (1) of the ESA. BLM also avoids making any irreversible or 

irretrievable commitment of natural resources that would foreclose any reasonable and 

prudent alternative measures that might be required as a result of the consultation on the 

CDCA plan in accordance with 7 (d) of the ESA. On November 3, 2000, the stipulation 

respecting Peirson’s milk-vetch became effective which temporarily closed approximately 

49,000 acres in the open area until the completion of this EIS and the respective RAMP.

Vehicle Types

The types of vehicles that are utilized at the ISDRA include off road and street-legal vehicles. 

The vehicle types that can be found at the ISDRA include: sand rails, dune buggies, allterrain vehicles, motorcycles, 4WD pickups, 2-WD pickups, sport utility vehicles and custom 

built off road vehicles. Private, law enforcement, military, commercial and rescue aircraft 

frequently fly over the dunes at low altitudes.
86

Regulatory Framework

Since its designation, the ISDRA has been managed according to mandates set forth in both 

the 1980 California Desert Conservation Area and the 1976 Federal Land Policy and 

Management Act. Among FLPMA’s requirements is: 

... the use of all California desert resources can and should be provided for in 

a multiple use and sustained yield management plan to conserve these 

resources for future generations, and to provide present and future use and 

enjoyment, particularly outdoor recreation uses, including the use, where 

appropriate, of off-road recreational vehicles... [Title VI. SC1781. Sec. 601 

(a)(4)]. 

The CDCA Plan of 1980, as amended provides overall management direction for all public 

lands in the CDCA. The CDCA Plan's Recreation Element lists several goals, as follows:

- Provide for a wide range of quality recreation opportunities and experiences emphasizing 

dispersed undeveloped use.

- Provide a minimum of recreation facilities. Those facilities should emphasize resource 

protection and visitor safety.

- Manage recreation use to minimize user conflicts, provide a safe recreation environment, 

and protect desert resources.

- Emphasize the use of public information and education techniques to increase public 

awareness, enjoyment, and sensitivity to desert resources.

- Adjust management approach to accommodate changing visitor use patterns and 

preferences.

- Encourage the use and enjoyment of desert recreation opportunities by special 

populations, and provide facilities to meet the needs of those groups (BLM, 1980).

To manage the desert resources, the CDCA Plan divided all public land within the plan 

boundaries, which includes the ISDRA, into Multiple-Use Classes that stipulate whether 

different areas could be used for motorized recreation, motorized access, and the intensity of 

that use. Because these classes are legally binding, unless amended through the public 

process, the BLM must manage the ISDRA according to the class prescriptions. 

1987 RAMP 

The BLM prepared a RAMP in 1987 to provide direction regarding resolving issues that 

were being experienced at the dunes. The 1987 RAMP included use statistics for 1977, 1978, 

and 1985, projected visitation and densities for 1986 through 2000, descriptions of use areas, 

and identification of the major issues at the dunes.

Public workshops were held to identify and prioritize management issues, concerns, and 

problems. The 12 major issues categories identified at the workshops are listed below:
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- Recreation opportunities

- Safety and emergency services

- Resource protection and 

enforcement

- Protection of Wilderness suitability

- Public contact and interpretation

- Facility development

- Operations and maintenance

- Concessions and vendors

- Acquisition of legal access and 

undeveloped state and private in 

holdings

- Compatibility of land uses

- Use fees

- Potential Desert Plan amendments

Ten of these issue categories were addressed by the 1987 RAMP. Two categories, Use fees 

and Potential Desert Plan amendments, were addressed in other forums. The 1987 RAMP 

included:

- A series of management objectives to be applied to the entire ISDRA

- Multiple-Use Class objectives

- Management constraints (the CDCA Plan, other activity plans, authorized uses other than 

recreation, and Wilderness interim management constraints)

The management program outlined in the 1987 RAMP included management prescriptions 

for the 10 major issue categories and prioritized them into four funding levels. The funding 

levels included Level 1 (reduced funding), Level 2 (maintain present management 

capability), Level 3 (modest improvements), and Level 4 (significant improvement in 

management capability) (BLM, 1987).

Current Situation

Recreation Visitation

The ISDRA is located within a three-hour drive from Los Angeles, Orange County, 

Riverside, San Diego, and Phoenix. The ISDRA is a highly valued and unique recreation 

resource within the southwestern United States for two reasons: (1) it is a sand dune 

ecosystem of a size and height unparalleled, and (2) it fills a unique and valued niche for 

providing the largest acreage of dunes oriented, motorized recreational opportunities in the 

United States. The ISDRA has far more acreage than the 10 other dune areas that are located 

within 1,500 miles.

Continued population growth in southern California, the expanding popularity of OHV 

recreation (108% increase since 1980 in California), and a 48% decrease in the acres 

available to OHV recreation in the California Desert, has resulted in a steady increase in 

visitation at the ISDRA. Due to the increased demand for OHV recreation there has been a 

need for increased law enforcement. 

The ISDRA provides for many types of recreational experiences with OHV recreation as the 

dominant activity. OHV enthusiasts who visit the ISDRA on holiday weekends will 

experience large crowds, noise, and intensive 24-hour OHV activity, in areas such as Glamis, 
88

Gecko, Dune Buggy Flats and Buttercup. There are other locations within the ISDRA where 

OHV recreation is less intense on holiday weekends and visitors can have a quieter, less 

intensive experience (Mammoth Wash or the Ogilby Areas). The majority of the opportunity 

lies during weekdays and non-holiday weekends when a range of recreational settings can 

accommodate many different types of experiences.

The ISDRA is managed to provide both non-motorized and motorized recreational 

opportunities to area residents and visitors. In addition to OHV recreation, the ISDRA 

provides other recreational opportunities including hiking, horse back riding, wildlife and 

scenery viewing, picnicking, photography, nature study and environmental education, 

camping, sightseeing and driving for pleasure. The ISDRA also provides a special niche that 

produces a particular social experience. It provides wide-open spaces where enthusiasts can 

seek solitude or a substantially modified natural environment with facilities for a highly 

intensified motorized recreation use experience.

The earliest known annual visitation at the ISDRA was 150,000 in the late 1970s; the number 

of visits had increased to 225,900 visits in 1985 (BLM, 1987). The average annual number of 

visits to the ISDRA over the 2-year period of 1999 to 2001 was over 750,000 (BLM, 2001). 

Between October 1, 1999, and September 30, 2000, there were 867,753 visits to the ISDRA. 

This is shown in Table 3.1-2. 

TABLE 3.1-2 ISDRA VISITS (1999-2000)A

Site Visits Visit (%)

Buttercup Campground 107,639 12.4

Dispersed – Imperial Dunes 571,319 65.8

Gecko Campground 107,639 12.4

Midway Camping Pad 16,231 1.9

Plank Road 16,231 1.9

Roadrunner Campground 48,694 5.6

Total 867,753 100.0

aThe 1999-2000 year is defined as October 1, 1999, through September 30, 2000.

bA “Visit” occurs when one person visits BLM lands to engage in any recreational activity, whether for a few 

minutes, full day, or more.

Source: BLM, 2001q

Annual visitation in fiscal year 2001 was estimated at 1.4 million visitors with peak visitation 

between October-April. (This is BLM’s visitation estimate based on 3.5 people per vehicle. 

During the public comment period, many visitors did not agree with this method of 

determining visitors. Visitor estimates for 2001 based on data from previous years places the 

visitation around one million people. BLM will conduct a visitor survey in the future to be 

able to better count visitors at the ISDRA.) Visitation to ISDRA is unevenly distributed 

throughout the year. The highest visitation at the ISDRA occurred during the six major 
89

holiday weekends that include: Halloween, Thanksgiving, Christmas/New Year, Martin 

Luther King, President’s Day and Easter. The visitation estimates for the major holiday 

weekends often exceed 100,000 visitors. In fact, 2001’s visitation during the Thanksgiving 

weekend was estimated at 240,000 visitors. 45% percent of the annual visitation occurs 

during approximately 19 percent of the recreation season (i.e., six weeks out of eight months 

in the season). These holiday days are significant spikes in visitation. 

Graph 3.1-3 This graph illustrates the extreme peaks in visitation at the Dunes. This data was collected during 

the 2001-2002 season through vehicle counters located at Gecko Rd., Osborne, Glamis off-ramp, the Wash Rd., 

Ogilby camp area, Gordons Well, and Grays Well. The vehicle counts were taken every Sunday morning and 

multiplied by 3.5 to extrapolate the visitor count.

Visitors to the ISDRA are predominantly Anglo (68%), relatively young (85% under 45 

years of age), and most (91%) have a high school education. Most visitors (82%) are from 

California, and another 15% are from Arizona. The most frequently mentioned activity 

pursued at ISDRA is OHV riding (90%). However only 35% identified OHV riding as the 

primary reason for visiting the dunes. Other reasons included: the dunes, friends, open space, 

play, accessible, curiosity, to get away, vacation, and to race. 94% of the visitors learned 

about the dunes from friends and family. (USFS, 1993)

Over 80 percent of the visitors to the ISDRA are repeat visitors (USFS, 1993). It is common 

for a camping party to consist of three or four generations of relatives who have been visiting 

the area over the years. This provides a sense of tradition, nostalgia, history, intergenerational 

bonding, and a sense of place attachment.

Visitation for FY'02

- -

Easter / Spring Break 

 President's 

 MLK 

 New Years 

Thanksgiving 

 Halloween 

-

50,000

100,000

150,000

200,000

250,000

300,000

Oct 6-8

Oct 19 - 22

Nov 2 - 5

Nov 15-19

Nov 29- Dec 3

Dec14 - 16

Dec 27 - 30

Jan 12 -15

Jan 25 - 27

Feb 7- 9

Feb 22- 24

Mar 8 - 11

Mar 22 - 24

Apr 6 -8 

Apr 19 -21

May 3 -5

May 17-19

Week

Visitation
90

Typical visitation includes relatively large groups for overnight stays. It is common to see 

overnight groups with 3 to 6 recreation “sleeping” vehicles, accompanying trailers, 10 to 

21 family members or friends, and multiple types of OHVs, staying for a 3-day weekend. 

Groups primarily camp in large recreation vehicles accompanied with many conveniences of 

home (e.g., chairs, tables, awnings, grills, firewood) (Haas, 2002).

The ISDRA is open to the public year-round. However, due to high temperatures throughout 

the dunes during the summer months, the recreation season is considered to be October 1 

through Easter of each year. Because the date of Easter varies from year to year and "spring 

breaks" offered by the various schools also differ, the end of the recreation season for this 

analysis is considered to be May 31st.

Gecko Road Visitation Oct 01 - May 02

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

Oct 6-8

Oct 19 - 22

Nov 2 - 5

Nov 15-19

Nov 29- Dec 3

Dec14 - 16

Dec 27 - 30

Jan 12 -15

Jan 25 - 27

Feb 7- 9

Feb 22- 24

Mar 8 - 11

Mar 22 - 24

Apr 6 -8 

Apr 19 -21

May 3 -5

May 17-19

Weekends

Visitation

Gecko Rd
91

Gray's Well Visitation OCT 01 -MAY 02

0

5000

10000

15000

20000

25000

30000

35000

Oct 6-8

Oct 19 - 22

Nov 2 - 5

Nov 15-19

Nov 29- Dec 3

Dec14 - 16

Dec 27 - 30

Jan 12 -15

Jan 25 - 27

Feb 7- 9

Feb 22- 24

Mar 8 - 11

Mar 22 - 24

Apr 6 -8 

Apr 19 -21

May 3 -5

May 17-19

Weekends

Visitation

Recreation Supply and Demand

The demand for recreation opportunities at the ISDRA peaks on approximately 12.5% of the 

recreation season (October 1 to May 30; that is, there is adequate capacity for those visitors 

who visit the ISDRA any time other than four major holiday weekends (Halloween, 

Thanksgiving, New Years and President’s weekends). 

The peak in use on the holiday weekends results in a change in several important social and 

managerial attributes of the setting, which then leads to a change in the recreation 

opportunity being provided. There is a change from providing the rural, roaded natural, and 

semi-primitive types of recreation opportunity to an urban recreation opportunity.

Facilities

Although camping is allowed everywhere within the recreation area, except for the Adaptive 

Management Area, the area available for two wheel drive vehicle overnight camping is 

limited to the visiting public. The sandy terrain limits access to most of the recreation area 

for vehicle camping. The acreage that is suitable is primarily along Gecko Road, the eastern 

and northern portion of the Glamis Management Area, the western side of the Mammoth 
92

Wash Management Area, the southwest portion of the Dune Buggy Flats Management Area, 

the eastern portion of the Ogilby Management Area, and the area adjacent to Greys Well 

Road in the Buttercup Management Area. 

The ISDRA has two developed campgrounds adjacent to Gecko Road. Gecko Campground 

is located approximately 3 1⁄2 miles south of SR 78. It consists of north and south loops that 

extend out into a rolling sand dunes area. Roadrunner Campground is located at the terminus 

of Gecko Road, approximately five miles south of SR 78. It consists of one loop that extends 

out into a flat sandy area. Both campgrounds are the only developed camping areas in the 

ISDRA. The southern portion of the Roadrunner loop and the northern loop of Gecko 

Campground are filled in with hard dirt / gravel material to provide camping space. Both 

campgrounds also provide trash facilities and pit toilets.

The BLM has constructed dirt / gravel “pads” in order to provide additional camping areas 

for two wheel drive vehicles. There are seven of these pads adjacent to Gecko Road and one 

adjacent to Grays Well Road.

The rest of the camping in the ISDRA is relatively dispersed although visitors tend to stay in 

historically used areas such as Glamis, the washes, Buttercup, and Dune Buggy Flats. These 

areas provide trash dumpsters, and some have pit toilets. The sites that do not have 

permanent pit toilets have portable toilets delivered and placed in the camping area during 

the high visitation periods.

Cahuilla Ranger Station is located on Gecko Road near SR 78. The station provides 

interpretive services and information to the visitors of the Dunes. It also serves as the 

incident command center during holiday weekends for the BLM and as a contact point for 

emergency services. The station is set up to accommodate two resident employees. One is 

the designated emergency medical technician and the other is the sector law enforcement 

ranger. There is also a maintenance shed to accommodate BLM OHV’s and emergency 

vehicles and supplies. The actual acreage available for overnight vehicle camping and the 

number of available campsites is provided in Chapter 4 for each alternative.

Recreation Settings

The majority of the visitation in the ISDRA occurs from October through May. Summer 

visitation level is extremely low due to extremely high temperatures. However, some OHV 

activity does occur during the summer nights. Typically, the ISDRA experiences high levels 

of visitation during Halloween, Thanksgiving, New Years, Martin Luther King Day, 

Presidents Day, and Easter. Visitors to the ISDRA during these time periods will experience 

crowds and noise. Visitor experiences during other times will be of low to moderate levels 

of visitor interaction.

In addition to the camping areas on the exterior of the Dunes, the visitors have historical 

congregation sites within the Dunes. “Vendor row” (aka the mall, the dustbowl) is an area in 

Glamis Flats that has been historically used for vending of commercial goods and services. 

The vendors set their sites along the south side of SR 78 between the Glamis Flats off-ramp 

and the Glamis private property line. Two rows form, facing each other with OHV traffic 
93

flowing between the vendors. A second line, similar in design, will set up along the west 

private property boundary of Glamis. These vendors are permitted through the BLM under 

the special recreation permit program. The holiday crowds, in conjunction with the vendors, 

seem to create a carnival atmosphere.

There are also historical gathering areas farther into the dunes where access is limited to 

OHVs. Some of these sites are Competition Hill, the sand drags, Oldsmobile Hill, Patton 

Valley, Test Hill, and Buttercup Valley. Visitors meet at these locations to test their OHVs, 

riding skills, and for informal competition. Visitation at these sites peak during different 

times of the day and are usually busiest during the holidays. Most of the locations are busiest 

during the day, except for Competition Hill and the sand drags. The crowds at the sand drags 

start to gather during the late afternoon and dissipate at dusk. The crowds at Competition 

Hill start gather around eight o’clock and can sometimes remain until after midnight.

The dunes can provide a place for the public to experience solitude and silence or busy 

crowds and noise. Under each ends of the spectrum, the visitor has the opportunity to 

experience vast wide-open spaces once out into the dunes system and away from the roads 

and campgrounds.

Recreation Programs

Recreation Programs at the ISDRA include developed and dispersed camping, and 

interpretive / informational / educational services. Although there are developed 

campgrounds in the ISDRA, there are no delineated camp spaces in any of the campgrounds. 

Camping is dispersed in both developed and primitive areas of the ISDRA. Interpretive / 

informational / educational services are provided at Cahuilla Ranger Station through displays 

and contact with a BLM Park Ranger. There are interpretive panels at the watchable wildlife 

site and the plank road that provide natural and cultural resource information. Informational 

kiosks are located in several locations throughout the Dunes near the major ingress/egress 

points. The private businesses sell maps of the area and also display and handout BLM 

literature free of charge. BLM staff frequently conducts informational stops at the major 

entry points in the dunes. BLM staff can hand out packets of literature to visitors as they 

enter the ISDRA. BLM also conducts guided hikes into the North Algodones Dunes 

Wilderness for the local community and school field trips as staffing allows. 

Visitors of the ISDRA prefer to receive information by signs (62%), notes on bulletin boards 

(57%), and by brochures given at the entrance to the area (51%). They are most interested in 

receiving information about safety (51%), agency management practices that could affect 

OHV riding (46%), and the area rules and regulations (45%). In 1993, only 32% of visitors 

were aware of the Cahuilla Ranger Station and only 12% had visited it. (USFS 1993) 

However, since this data was collected, the BLM believes these figures have increased 

substantially. This is partially due to a realignment of the fencing at the Station to make it 

more visitor friendly, and the inception of the fee demonstration project. The fees instituted 

in the dunes have required many of the visitors to stop at the Station in order to purchase a 

pass to the area.
94

Due to the level of visitation and lack of funding, Imperial County and the BLM work 

closely together on most medical rescues that occur in the dunes. The rescue work has 

become an integral part of the recreation division in the El Centro Field Office. The BLM 

continues to increase its coordination of rescue services with the county each year. In the 

field, both BLM emergency medical technicians and Imperial County contracted advanced 

life support ambulance personnel work together as a team to provide the best level of medical 

aid possible. The BLM has the off-highway 4x4 vehicles and two rescue buggies, and the 

skilled staff to extract accident victims from the dunes and transport them to the nearest 

paramedic ambulance. See Chapters 3.3 and 4.3 for more information on law enforcement 

and rescue.

Management Practices

A variety of practices can be used to manage recreation resources at the ISDRA. The BLM 

has a program that monitors both natural, cultural, and recreational resources. The BLM 

monitors sensitive plant, animals and habitats throughout the open and closed areas in the 

dunes. Transects are walked and driven to record plant and animal densities, and hidden 

automatic cameras are used to photograph animals using water sources in the dunes. Visitor 

use is monitored through newly installed traffic counters, and has been done in the past with 

aerial flights during the weekends. The BLM also conducts visitor surveys, in cooperation 

with special interest groups, to inventory visitor satisfaction and needs. Using these 

inventories, BLM managers estimate how well they are meeting national, state, and local 

goals, and adjust actions accordingly.

Historical Trends

Although it is believed that the fluctuation in the economy can cause yearly fluctuations in 

visitation to the ISDRA, the level of visitation has increased over time. Between 1980 and 

2001 there has been an increase of 108% of the registered OHV in California. Between 1994 

and 2001 there has been an increase of 74% of street licensed 4 wheel drive vehicles. 

Between 1980 and 2000 there has been a 48% decrease in the amount of acres available for 

OHV recreation (Taking the High Road, CA State Parks, 2002). Many of the other major 

dune recreation areas in the CDCA have been closed to motorized recreation. Only Dumont 

Dunes and the ISDRA remain open to OHV recreation. Within the ISDRA, 26,202 acres 

(16%) of the ISDRA has been closed to OHVs as a congressionally designated wilderness. 

The old wilderness study area 362 (central dunes) has been released from further wilderness 

study. 

Later model OHVs are much more technologically advanced than the old standard OHVs. 

OHVs are more powerful, and have better suspension and traction. This has led to faster and 

more reliable vehicles. The types of OHVs have also diversified. It is not unusual to see 

standard dune buggies, long travel dune buggies, motorcycles, all terrain vehicles, all terrain 

cycles, golf carts, odysseys, 4-wheel drives, and custom vehicles only limited by the 

imagination of the builder. Many of the new OHVs will cost as much as $50,000.

OHV enthusiasts are also using more technological equipment as part of their recreational 

experience. Many enthusiasts are using global positioning systems to navigate through and 

around the sand dunes. The use of cellular phones has also helped in circumstances when a 

person is lost, injured, or stranded due to mechanical malfunction.
95

Camping units have increased in size. Current motor homes and trailers are as long as a 

semi-truck and much wider. The invention of the “slide out” can make a parked unit up to 15 

feet wide. OHV trailers come as enclosed two story units to increase the capacity of OHVs. 

New motor homes and trailers have all the comforts of home including satellite dish TV, 

refrigerator and freezer, microwave ovens, desktop or laptop computers, and telephones. 

These conveniences make it easier for the visitors to have an extended stay. Although there 

are many visitors who still “rough it” in a tent and a pick up truck, many of the visitors will 

also have over $100,000 invested in their OHV, trailer, and camping unit.

Over the last five years both the public and the BLM have noticed a change in the type of 

visitation in the ISDRA. As other locations in the southwest were being shut down by law 

enforcement to young crowds of “party types” this type of activity and visitation has 

increased in the dunes. The visitation of young people who were in the dunes to “party” and 

not to recreate on OHVs increased, especially on holidays. In response to this trend the BLM 

has enacted a special law enforcement program to discourage illegal activities at the dunes. 

After one season (2001/2002) of the high level of law enforcement there has already been a 

change in the level of inappropriate activity. The BLM feels that the continued enforcement 

has started to make a difference in the ISDRA and it has resulted in a safer, family oriented 

recreation area.

Future Trends

California has the highest state population in the nation with a population of 34 million in 

2000, and a projected population of 46 million in 2020. California also has the greatest 

number of OHV enthusiast in the nation with 3.5 million recreationists, 14.2% of all 

households. California OHV registration has increased 108% since 1980 and there has been 

a 74% increase in street legal four-wheel drive vehicles since 1994. Southern California has 

the majority of the OHV owners while it has the less opportunity than other parts of the state. 

Legal OHV opportunities have decreased 48% in the California Desert since 1980. (Taking 

The High Road, 2002). This information, coupled with the knowledge that 82% of all 

visitors to the dunes are from California (USFS, 1993), and the ISDRA supplies a specific 

niche of OHV recreation not found anywhere else in the nation, leads the BLM to believe 

that conflicts will be inevitable in the future. The continued cooperation and involvement of 

all special interest groups and local, state, and federal agencies will be necessary to continue 

to sustain a quality recreational experience for the years to come.
96

3.2 Biological Resources

Regulatory Framework

Federal Endangered Species Act

The Federal Endangered Species Act (FESA) of 1973, as amended, provides the regulatory 

framework for the protection of threatened and endangered (T&E) plant and animal species 

formally listed under the FESA, as well as their designated critical habitat. The USFWS, in 

consultation with other federal agencies, administers and enforces the FESA. The following 

terms are defined by the FESA:

Endangered: Any species that is in danger of extinction throughout all or a significant 

portion of its range.

Threatened: Any species that is likely to become an endangered species within the 

foreseeable future throughout all or a significant portion of its range.

Proposed: Any species that has been proposed for listing as a threatened or 

endangered species.

Critical Habitat: “... the specific areas within the geographical area occupied by the 

species ... on which are found those physical or biological features (I) essential to the 

conservation of the species and (II) which may require special management 

considerations or protection... ” 

California Endangered Species Protection

The California Endangered Species Act (CESA) of 1984 and the California Native Plant 

Protection Act (CNPPA) of 1977 provide the framework for protection of California listed 

T&E plant or animal species or rare plant species. Protection by the state is also offered to 

candidate species that have been accepted for state review for potential listing as endangered, 

threatened, or rare. The following terms are defined by the CESA:

Endangered: A native species or subspecies of animal or plant that is endangered of 

becoming extinct throughout all, or a significant portion, of its range due to one or 

more causes, including loss of habitat, change of habitat, overexploitation, predation, 

competition, or disease. 

Threatened: A native species or subspecies of animal or plant that, although not 

currently threatened with extinction, is likely to become an endangered species in the 

foreseeable future in the absence of the special protection and management efforts 

required by Chapter 1.5 of the California Fish and Game Code.

Rare: A species, subspecies, or variety of plant is rare when, although not currently 

threatened with extinction, it is in such small numbers throughout its range that it may 

become endangered if its present environment worsens. 

Candidate: A native species or subspecies of animal or plant that the California Fish 

and Game Commission (CFGC) has formally noticed as being under review by the 
97

CDFG for addition to either the endangered or threatened species list, or a species for 

which the CFGC has published a notice of proposed regulation to add the species to 

either list.

Species of Special Concern: Native species or subspecies of animal or plant that has 

become vulnerable to extinction because of declining population levels, limited 

ranges, or rarity. The goal is to prevent these species from becoming endangered by 

addressing the issues of concern early enough to secure long-term viability. 

BLM Special-Status and Sensitive Species 

The BLM recognizes a special-status species as an animal or plant that meets any one of the 

following criteria: (1) it is federally listed as endangered or threatened; (2) it is federally 

proposed as endangered or threatened; (3) it is a federal candidate for listing; (4) it is state 

listed as Rare, Threatened, or Endangered; or (5) it has been designated by the BLM State 

Director as a sensitive species. Additionally, all List 1B plants in the 6th edition of the 

California Native Plant Society (CNPS) Inventory that are on BLM lands, and do not meet 

any of the first four of the special-status species criteria, are considered sensitive species. 

California Native Plant Society 

The CNPS is a professional society of botanists, biologists, scientists, and other associated 

professionals who have accumulated a statewide database on California native plant 

abundance and distribution. The CNPS has developed four categories to describe the status 

of plants species as: rare, threatened, endangered, or extinct. Although these listings do not 

afford legal status or protection for the species, agencies consult the list in their planning 

process for activities that may potentially impact any of these species. The listing categories 

are as follows:

- CNPS 1A: Plant Species presumed to be extinct in California.

- CNPS 1B: Plant species presumed to be rare, threatened, or endangered in California and 

elsewhere.

- CNPS 2: Plant species presumed to be rare, threatened, or endangered in California but 

common elsewhere.

- CNPS 3: Plant species for which more information is needed to be properly categorized, 

and includes an assemblage of taxa that have been transferred from other lists or have 

been suggested to CNPS for consideration. 

- CNPS 4: Plant species that are not currently threatened or vulnerable but are considered 

to have limited distribution in California and, because of their uncommon status, should 

be monitored.

California Natural Diversity Database

The California Natural Diversity Database (CNDDB) is a computerized inventory of data on 

the general location and condition of California’s rare, threatened, and endangered animals, 

plants, and natural communities that CDFG maintains. The database also maintains 

inventories of federally listed T&E species. The CNDDB includes species that the scientific 

community feels deserving of an official listing, species proposed for federal listing, U.S. 

Forest Service (USFS) special-status species, and state candidate species. 
98

Migratory Bird Treaty Act

The USFWS administers and enforces the Migratory Bird Treaty Act (MBTA) of 1918 (16 

USC 701-718h). Virtually all birds are protected under the MBTA, with four exceptions 

(California quail, English sparrows, common pigeons, and European starlings). The MBTA 

controls the taking of these birds, their nests, eggs, parts, or products without obtaining a 

permit from the USFWS.

U.S. Fish and Wildlife Service Consultation and Conference

Section 7 of the FESA mandates federal agencies that fund, authorize, or carry out actions 

that may affect listed species or adversely modify their critical habitat must consult with the 

USFWS. It is the responsibility of the action agency to determine if their actions may affect 

listed species. If the action agency makes a “may affect” determination, then that agency 

should initiate an informal consultation with the USFWS. During informal consultation, it 

will be determined if the action will adversely affect the species, in which case formal 

consultation will be initiated. 

Formal consultation is not required if the USFWS concurs in writing that an action will not 

adversely affect the species. However, if it is determined that the action may adversely affect 

T&E species, then formal consultation will be initiated. As part of the formal consultation 

process, the action agency prepares a biological assessment/evaluation that contains a 

description of the proposed action, map of the project area, potential effects to listed species 

or critical habitat, and any relevant reports. 

Once completed, formal consultation results in a biological opinion issued from the USFWS 

to the action agency. The biological opinion will contain the following information: (1) an 

analysis of the direct, indirect, interrelated, interdependent, and cumulative effects; (2) a 

determination of whether the action is likely or not likely to jeopardize the continued 

existence of the species; (3) an incidental take statement for wildlife that will identify the 

anticipated level of take; (4) mandatory reasonable and prudent measures and the terms and 

conditions to minimize incidental take; and (5) discretionary conservation recommendations 

that would further minimize impacts and promote conservation of the species.

When a proposed action affects a species proposed for listing as threatened or endangered, a 

formal conference (as opposed to a consultation for a listed species) with the USFWS may be 

required. Unlike biological opinions, recommendations made in conference opinions are 

advisory and therefore nonbinding. The primary purpose of conferencing is to avoid delay of 

a proposed action should a species proposed for listing become listed, and to ensure that the 

proposed action does not jeopardize a species’ recovery potential. Should a species become 

formally listed prior to implementation of the proposed action, a federal agency is required to 

informally consult with the USFWS regarding the conference opinion. In the absence of 

additional new information, USFWS may adopt the formal conference opinion as the 

biological opinion without the federal agency having to initiate formal consultation.

The BLM request formal consultation on the Threatened Peirson's milk-vetch (Astragalus 

magdalenae var. peirsonii) and desert tortoise (Gopherus agassizii). BLM has received a 

Biological Opinion for the preferred alternative in this EIS from the USFWS. 

 
99

BLM Policies and Plans

The goal of the CDCA Plan is to provide for the use of public lands and resources of the 

CDCA, including economic; educational; scientific; and recreational uses; as well as 

protection of environmental, cultural, and aesthetic values of the desert and its future 

productivity. Carrying forth the management principles from FLPMA, the Plan establishes 

MUCs for the lands involved and establishes a framework for managing the various 

resources within these classes. The four uses include: Class C (controlled), Class L (limited), 

Class M (moderate) and Class I (intensive). 

The CDCA incorporates the ISDRA and therefore provides general management guidance 

for the area. The CDCA Plan decision rationale and summary of resource values for 

Planning Unit Number 103, which includes the Algodones Dunes Wildlife Habitat Area 

(WHA), delineated the management goals for protection of rare and endangered wildlife and 

vegetation; enhancement of wildlife values; and extensive monitoring, especially of potential 

impacts to these resources from vehicle use.

FLPMA defines an Area of Critical Environmental Concern (ACEC) as an area within public 

lands where special management attention is required to protect and prevent irreparable 

damage to important historic, cultural, or scenic values; fish and wildlife resources; other 

natural system processes; or to protect human life and safety from natural hazards (USDI, 

1980). ACECs are managed for special use, but with special restrictions; and they do not 

preclude appropriate development if protection of sensitive values can be assumed.

The Plan Area includes a portion of the East Mesa ACEC, located adjacent to the southwest 

corner of the ISDRA. This ACEC was established on September2, 1988, to protect the flattailed horned lizard (Phrynosoma mcallii) and two rare plant species: Thurber’s pilostyles 

(Pilostyles thurberi ) and Salton milk-vetch (Astragalus crotalariae), as well as cultural 

resources associated with the Lake Cahuilla shoreline. 

Habitat Types

The biological resources of the Plan Area includes several dune habitats that support a 

variety of desert plant and wildlife species, including special-status and endemic species

found only at the Imperial Sand Dunes. The primary habitat types associated with the dune 

system are: Creosote Bush Scrub, Microphyll Woodland, Psammophytic Scrub, and CanalInfluenced Vegetation (Westec, 1977; BLM, 1987). Habitat types are depicted in Figure 

3.2-1 and described in detail below. 
100

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101

View Figure 3.2-1

Habitat types - 99Kb
102

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103

Table 3.2-1 lists the plant species that are known or have the potential to occur in the ISDRA. 

Table 3.2-2 lists the wildlife species that are known or have the potential to occur in the 

ISDRA.

TABLE 3.2-1 LIST OF PLANT SPECIES THAT ARE KNOWN 

 OR HAVE THE POTENTIAL TO OCCUR IN THE ISDRA

Common Name Scientific Name Status

Algodones Dunes sunflower Helianthus niveus ssp.

tephrodes

SE/CNPS-1B

Arrow weed Pluchea sericea

Big galleta Hilaria rigida

Birdcage evening-primrose Oenothera deltoides

Borrego milk-vetch Astragalus lentiginosus var.

borreganus

CNPS-4

Brittlebush Encelia farinosa

Brown plume wirelettuce Stephanomeria pauciflora

Burrobush Ambrosia dumosa

Burrobrush Hymenoclea salsola

California ditaxis Ditaxis serrata var. california CNPS-3

California threeawn Aristida californica

Carrizo mallow Sphaeralacea orcuttii

Cattail Typha spp.

Common sandpaper plant Petlonyx thurberi

Common sunflower Helianthus annuus

Coulter’s lyrepod Lyrocarpa coulteri var. 

palmeri

CNPS-4

Creosote bush Larrea tridentata

Crown-of-thorns Koeberlina spinosa ssp. 

Tenuispina

CNPS-2

Desert buckwheat Eriogonum deserticola

Desert dicoria Dicoria canescens

Desert lily Hesperocallis undulata

Desert panicum Panicum urvilleanum

Desert starvine Brandegea bigelovii
104

TABLE 3.2-1 LIST OF PLANT SPECIES THAT ARE KNOWN 

 OR HAVE THE POTENTIAL TO OCCUR IN THE ISDRA

Common Name Scientific Name Status

Desert thron-apple Datura discolor

Desert unicorn plant Proboscidea altheafolia CNPS-4

Desert willow Chilopsis linearis

Dyebush Dalea emoryi 

Fairy duster Calliandra eriophylla CNPS-2

False daisy Eclipta alba

Fennel-leaf pondweed Potamogeton pectinatus

Foxtail cactus Coryphantha alversonii CNPS-4

Giant reed Arundo donax

Giant Spanish needle Palafoxia arida var. gigantea BLM/CNPS-1B

Glandular ditaxis Ditaxis clariana CNPS-2

Hairy stickleaf Mentzelia hirsutissima CNPS-2

Harwood milk-vetch Astragalus insularis var. 

harwoodii

CNPS-4

Honey mesquite Prosopis glandulosa

Horseweed Conyza canadensis

Ironwood Olneya tesota

Lineleaf white puff Oligomeris linifolia

Longleaf jointfir Ephedra trifurca

Mediterranean grass Schismus barbatus

Mormon tea Ephedra trifurca

Munz’s cholla Opuntia munzii BLM/CNPS-1B

Orocopia sage Salvia greatei BLM/CNPS-1B

Palmer’s crinklemat Coldenia palmeri

Palo verde Cercidium floridum

Peirson’s milk-vetch Astragalus magdalenae var.

peirsonii

FT/SE/CNPS-1B

Plicate Coldenia Tiquilia plicata

Ribbed cryptantha Cryptantha costata CNPS-4
105

TABLE 3.2-1 LIST OF PLANT SPECIES THAT ARE KNOWN 

 OR HAVE THE POTENTIAL TO OCCUR IN THE ISDRA

Common Name Scientific Name Status

Rock nettle Eucnida rupestris CNPS-2

Rush milkweed Ascelpias subulata

Sand food Pholisma sonorae BLM/CNPS-1B

Shortspike watermilfoil Myripphyllum exalbescens

Small-flowered tamarisk Tamarix parviflora

Smoke tree Psorothamnus spinosa

Spiny chloracantha Aster spinosus

Spotted cadythumb Polygonum fusiforme

Thurber’s pilostyles Pilostyles thurberi CNPS-4

White ratany Krameria grayi

White sweetclover Melilotus albus

Wiggins’ cholla Opuntia wigginsii CNPS-3

Wiggins’ croton Croton wigginsii SR/CNPS-2

Winged cryptantha Cryptantha holoptera CNPS-4

Woolly desert marigold Baileya pleniradiata

Legend:

FT: Federal threatened

SE: California state endangered

SR: California state rare

 BLM: BLM Sensitive Species

CNPS: California Native Plant Society:

1B – Taxa determined to be rare, threatened, or endangered in California and elsewhere

2 – Species rare or endangered in California but common elsewhere

3 – More information on status needed

4 – Species of limited distribution
106

TABLE 3.2-2 LIST OF WILDLIFE SPECIES THAT ARE KNOWN 

 OR HAVE THE POTENTIAL TO OCCUR IN THE ISDRA

Common Name Scientific Name Status

Mammals

American badger Taxidea taxa

Antelope ground squirrel Ammospermophilus leucurus

Big brown bat Eptesicus fuscus

Black-tailed hare Lepus californicus

California leaf-nosed bat Macrotus californicus BLM

Cave myotis Myotis velifer BLM

Colorado River cotton rat Sigmodon arizonae plenus

Coyote Canis latrans

Desert cottontail rabbit Sylvilagus audubonii

Desert kangaroo rat Dipodomys deserti

Desert pallid bat Antrozous pallidus pallidus

Desert woodrat Neotoma lepida

Greater western mastiff bat Eumops perotis californicus 

Kit fox Vulpes macrotis

Merriam’s kangaroo rat Dipodomys merriami

Mule deer Odocoileus hemionus

Occult little brown bat Myotis lucifugus occultism

Raccoon Procyon lotor

Roundtail ground squirrel Spermophilus tereticaudus

Small-footed myotis Myotis ciliolabrum

Spotted bat Euderma maculatum BLM

Townsend’s big-eared bat Plecotus townsendii BLM

Western pipistrel Pipistrellus hesperus

White-throated woodrat Neotoma albigula venusta
107

TABLE 3.2-2 LIST OF WILDLIFE SPECIES THAT ARE KNOWN 

 OR HAVE THE POTENTIAL TO OCCUR IN THE ISDRA

Common Name Scientific Name Status

Wild burro Equus asinus

Yuma hispid cotton rat Sigmodon hispidus eremicus

Yuma myotis Myotis yumanensis

Yuma mountain lion Felis concolor browni

Birds

American Coots Fulica americana

American Kestrel Falco sparverius

Arizona Bell’s Vireo Vireo bellii arizonae SE

Barn Owl Tyto alba

Black Tern Coalitionist niger

Black-tailed Gnatcatcher Polioptila melanura

Black-throated Sparrow Amphispiza bilineata

Burrowing Owl Athene cunicularia BLM

Cactus Wren Campylorhynchus 

burnnecapillus

Cliff Swallow Hirundo pyrrhonota

Common Yellowthroats Geothlypis trichas

Crissal Thrasher Toxostoma dorsale

Ferruginous Hawk Buteo regalis

Gambel’s Quail Lophortyx gambelli

Gila Woodpecker Melanerpes uropygialis SE

Gilded Northern Flicker Colaptes auratus chrysoides

Golden Eagle Aquila chrysaetos

Great Horned Owl Bubo virginianus

House Finch Carpodacus mexicanus

Ladder-backed Woodpecker Picoides scalaris
108

TABLE 3.2-2 LIST OF WILDLIFE SPECIES THAT ARE KNOWN 

 OR HAVE THE POTENTIAL TO OCCUR IN THE ISDRA

Common Name Scientific Name Status

LeConte’s Thrasher Toxostoma lecontei BLM

Lesser Nighthawk Chordeiles acutipennis

Loggerhead Shrike Lanius ludovicianus

Long-eared Owl Asio otus

Marsh Wren Cistothorus palustris

Merlin Falco columbarius

Mountain Plover Charadrius montanus

Mourning Dove Zenaida macroura

Northern Harrier Circus cyaneus

Peregrine Falcon Falco peregrinus SE

Prairie Falcon Falco mexicanus

Red-tailed Hawk Buteo jamaicensis

Red-wing Blackbird Agelaius phoeniceus

Say’s Phoebe Sayornis saya

Sharp-shinned Hawk Accipiter striatus

Southwestern Willow 

Flycatcher

Empidonax trailii extimus FE/SE

Turkey Vulture Cathartes aura

Vaux’s Swift Chaetura vauxi

Verdin Auriparus subulata

Warbling Vireo Vireo gilvus

Western Flycatcher Empidonax difficilis

Western Least Bittern Lxobrychus exilis hasperus

Western Screech Owl Otus kennicottii

Western Yellow Billed 

Cuckoo

Coccyzus americanus 

occidentalis

SE
109

TABLE 3.2-2 LIST OF WILDLIFE SPECIES THAT ARE KNOWN 

 OR HAVE THE POTENTIAL TO OCCUR IN THE ISDRA

Common Name Scientific Name Status

White-crowned Sparrow Zonotrichia leucophrys

White-faced Ibis Plegadis chichi

Wilson’s Warbler Wilsonia pusilla

Yellow-headed Blackbird Xanthocephalus 

zanthocephalus

Yellow-rumped Warbler Dendroica coronata

Insects

Andrews’ dune scarab beetle Psuedocotalapa andrewsi

Brow-tassel weevil Trigonoscuta brunnotasselata

Carlson’s dune beetle Anomala carlsoni

Cheeseweed owlfly Oliarves clara

Hardy’s dune beetle Anomala hardyorum

Amphibians

Arizona southwestern toad Bufo microscaphus 

microscaphus

Couch’s spadefoot toad Scaphiopus couchi BLM

San Sebastian leopard frog Rana yavapaiensis BLM

Reptiles

Chuckwalla Sauromalus obesus

Colorado Desert fringe-toed 

lizard 

Uma notata BLM

Desert iguana Dipsosaurus dorsalis 

Desert tortoise Gopherus agassizii FT/ST

Flat-tailed horned lizard Phrynosoma mcallii BLM

Rosy boa Lichanura trivirgata

Side-blotched lizard Uta stansburiana

Sidewinder rattlesnake Crotalus cerastes
110

TABLE 3.2-2 LIST OF WILDLIFE SPECIES THAT ARE KNOWN 

 OR HAVE THE POTENTIAL TO OCCUR IN THE ISDRA

Common Name Scientific Name Status

Western whiptail lizard Cnemidophorus tigris

Zebra-tailed lizard Callisaurus draconoides

Legend:

FE: Federal listed as endangered 

FT: Federal listed as threatened 

 FPT: Federal proposed as threatened

 SE: California state listed as endangered

ST: California state listed as threatened

BLM: BLM Sensitive Species

Creosote Bush Scrub

Creosote bush scrub is the most common habitat type in the Colorado Desert and typically 

occurs on well-drained secondary soils of slopes, fans, and valleys. Within the ISDRA, this 

habitat type occurs on the relatively stable soils along the periphery of the dune system. It 

rarely occurs in the central portion of the ISDRA where shifting dunes are prevalent. This 

habitat type is generally characterized by relatively barren ground between widely spaced 

shrubs. To the west of the ISDRA, the habitat consists of almost pure stands of creosote 

bush. On the eastern boundary of the ISDRA, the vegetation is more diverse due to the 

topographic relief of the dunes and runoff from the nearby Chocolate and Cargo Muchacho 

Mountains. The creosote bush scrub within the alluvial fan between the desert washes forms 

a transitional zone with the microphyll woodland habitat type. This habitat type covers 

approximately 51,831 acres of the entire Plan Area. Characteristic plant species of this 

habitat type include creosote bush (Larrea tridentata), brittlebush (Encelia farinosa), and 

burrobush (Ambrosia dumosa). Less abundant species associated with this habitat type 

include woolly desert marigold (Baileya pleniradiata), birdcage evening-primrose 

(Oenothera deltoides), dyebush (Dalea emoryi), longleaf jointfir (Ephedra trifurca), desert 

thorn-apple (Datura discolor), big galleta (Hilaria rigida), white rhatany (Krameria grayi), 

and brown plume wirelettuce (Stephanomeria pauciflora).

The wildlife commonly associated with this creosote bush scrub include desert iguana 

(Dipsosaurus dorsalis), zebra-tailed lizard (Callisaurus draconoides), western whiptail lizard 

(Cnemidophorus tigris), Red-tailed Hawk (Buteo jamaicensis), Mourning Dove (Zenaida 

macroura), Lesser Nighthawk (Chordeiles acutipennis), Black-tailed Gnatcatcher (Polioptila 

melanura), Yellow-rumped Warbler (Dendroica coronata), White-crowned Sparrow 

(Zonotrichia leucophrys), big brown bat (Eptesicus fuscus), kit fox (Vulpes macrotis), 

roundtail ground squirrel (Spermophilus tereticaudus), and black-tailed hare (Lepus 

californicus). Special-status or sensitive wildlife species that may occur in this habitat 

include desert tortoise, flat-tailed horned lizard, Western Burrowing Owl (Athene 

cunicularia), and LeConte’s Thrasher (Toxostoma lecontei). The endemic Hardy’s dune 
111

beetle (Anomala hardyorum) and Carlson’s dune beetle (Anomala carlsoni) are also found in 

this habitat type (Hardy and Andrews, 1979). 

Psammophytic Scrub

Psammophytic scrub occurs within the interior dune system where active and partially 

stabilized dunes are found. This habitat type occurs most frequently between active dunes in 

depressions that are commonly termed “bowls.” The soils in these areas consist primarily of 

fine sand. As the dunes shift from year to year, the bowls generally shift as well. Vegetation 

is adapted to relatively high sand mobility and deep water percolation. Most of these plant 

species are capable of rapid growth given favorable soil moisture conditions. This habitat 

type covers approximately 107,685 acres of the entire Plan Area. Common vegetation of this 

habitat type include Mormon tea (Ephedra nevademsis), desert buckwheat (Eriogonum 

deserticola), desert dicoria (Dicoria canescens), common sandpaper plant (Petalonyx 

thurberi), desert panicum (Panicum urvilleanum), and plicate coldenia (Tiquilia plicata). 

Additionally, birdcage evening primrose and desert lily (Hesperocallis undulata) may occur 

in the relatively stable dunes that form a transitional zone with the creosote bush scrub 

habitat. 

The wildlife commonly associated with psammophytic scrub include Black-tailed 

Gnatcatcher, Mourning Dove, Cliff Swallow (Hirundo pyrrhonota), coyote (Canis latrans), 

roundtail ground squirrel, desert kangaroo rat (Dipodomys deserti), and black-tailed hare. 

The Colorado desert fringe-toed lizard (Uma notata) is the only sensitive wildlife species 

known to almost exclusively inhabit this area. The endemic Andrew’s dune scarab beetle 

(Psuedocotalapa andrewsi) is also found in this habitat type (Hardy and Andrews, 1979).

Microphyll Woodland 

To the east of the dune system is a large alluvial fan draining the Chocolate and Cargo 

Muchacho mountains. The alluvial fan is dissected by numerous ephemeral washes and 

separated by expansive, level interfluves. The desert microphyll woodland typically is best 

developed in the larger drainages where dense stands of a variety of trees occur. Microphyll 

woodland is generally found along the margins of these dry channels, and around the cul-desac sinks of their terminii. This habitat type covers approximately 64,906 acres of the entire 

Plan Area. Vegetation is generally sparse in the open wash areas between the sinks. Typical 

vegetation of this habitat type include palo verde (Cercidium floridum), ironwood (Olneya 

tesota), smoke tree (Psorothamnus spinosa), and to a lesser degree honey mesquite (Prosopis 

glandulosa), desert willow (Chilopsis linearis), and desert unicorn plant (Proboscidea 

altheafolia). Depending upon rainfall, the understory in the plains is generally composed of 

shrubs and annuals such as desert starvine (Brandegea bigelovii), carrizo mallow 

(Sphaeralacea orcuttii), California threeawn, Mediterranean grass (Schismus barbatus), 

lineleaf white puff (Oligomeris linifolia), and rush milkweed (Asclepias subulata). 

The plant diversity and density combined with the micro-topographic variability associated 

with the washes, accounts for a high diversity of wildlife in the microphyll woodlands. The 

wildlife commonly associated with this habitat type include side blotched lizard (Uta 

stansburiana), western whiptail lizard, zebra-tailed lizard, sidewinder rattlesnake (Crotalus 

cerastes), Red-tailed Hawk, Gambel’s Quail (Lophortyx gambelli), Mourning Dove, Ladderbacked Woodpecker (Picoides scalaris), Verdin (Auriparus flaviceps), Western Flycatcher 

(Empidonax difficilis), Cactus Wren (Campylorhynchus burnneicapillus), Warbling Vireo 
112

(Vireo gilvus), Wilson’s Warbler (Wilsonia pusilla), House Finch (Carpodacus mexicanus), 

Black-tailed Gnatcatcher, White-crowned Sparrow (Zonotrichia leucophrys), western 

pipistrelle bat (Pipistrellus hesperus), coyote, kit fox, mule deer (Odocoileus hemionus), 

white-tailed antelope squirrel (Ammospermophilus leucurus), black-tailed hare, and desert 

cottontail (Sylvilagus audubonii). Special-status or sensitive wildlife species that may occur 

in this habitat include desert tortoise, Couch’s spadefoot toad (Scaphiopus couchi), Gila 

Woodpecker (Melanerpes uropygalis), Western Burrowing Owl, and LeConte’s Thrasher. 

The wildlife guzzlers installed by the CDFG to partially mitigate impacts from the 

construction of the New Coachella Canal has created limited herbaceous weedy vegetation 

within the microphyll woodland. The presence of water and forage around the guzzlers has 

attracted mule deer from the Chocolate Mountain range. Mule deer are known to use the 

microphyll woodlands associated with washes as corridors through the North Algodones 

Dunes Wilderness Area and into the southern part of Mammoth Wash area. It is thought that 

the Yuma puma (Felis concolor browni) has followed the deer into the woodland to prey the 

mule deer. 

Canal-Influenced Vegetation

Both the Coachella and All American Canals support hydrophytic vegetation that is subject 

to periodic eradication efforts. Although the canals are lined, some seepage occurs and 

promotes the growth of hydrophytic vegetation. Submergent species include shortspike 

watermilfoil (Myriopphyllum exalbescens) and fennel-leaf pondweed (Potamogeton 

pectinatus). Emergent and upland species include cattails (Typha spp.), spotted cadythumb 

(Polygonum fusiforme) horseweed (Conyza canadensis), spiny chloracantha (Aster spinosus), 

giant reed (Arundo donax), small-flowered tamarisk (Tamarix parviflora), false daisy

(Eclipta alba), common sunflower (Helianthus annuus), white sweetclover (Melilotus albus), 

and arrow weed (Pluchea sericea). 

This manmade habitat is utilized by a variety of birds including American Coot (Fulica 

americana), Red-wing Blackbird (Agelaius phoeniceus), Yellow-headed Blackbird 

(Xanthocephalus xanthocephalus), Common Yellowthroat (Geothlypis trichas), and Marsh 

Wren (Cistothorus palustris). Common mammals of this habitat include black-tailed hare, 

coyote, raccoon (Procyon lotor), and American badger (Taxidea taxus). 

Special-Status Plant Species 

The designation of special-status includes federal- and state-listed species under either the 

federal or CESA, species proposed for federal listing, federal candidate species, and species 

designated as sensitive by the California State Director of the BLM (these include all plants 

on List 1B of the most recent CNPS Inventory of Rare and Endangered Plants of California). 

The following special-status plant species are known to occur within the Plan Area. 

Therefore, these species may be affected by activity in the Plan Area. Descriptions of these 

species are provided below.

Peirson’s Milk-Vetch (Astragalus magdalenae var. peirsonii) 

Status

Peirson’s milk-vetch was proposed as endangered in 1992 and listed as threatened in 1998 

(Federal Register, 1998). It is also recognized as endangered by the State of California and 
113

as a special-status species by the BLM. The CNPS lists the milk-vetch as a category 1B (rare, 

threatened, or endangered in California and elsewhere throughout its range) (Tibor, 2001). 

Critical habitat has not been designated for this species nor has a recovery plan been 

prepared. 

Life History

Peirson’s milk-vetch is a short-lived perennial reaching 8 to 30 inches high. The stems and 

leaves are pubescent, and the leaves are 2 to 6 inches long. The flowers are dull purple and 

are arranged in 10 to 17 flowered racemes. The resulting seed pods are 0.8 to 1.5 inches long 

and are inflated with a triangular beak (Bowers, 1996). This species is able to become 

reproductive in a single season. It generally completes seed production by June. By July, the 

plant has dropped many of its leaflets and some entire leaves. This condition may persist 

from July to October. Seedlings may be present in December, although not in great numbers. 

Seedlings that germinate by November or December may reach the flowering or fruiting 

stage by March (Romspert and Burk, 1979). 

Seeds of the Peirson’s milk-vetch are the largest of any North American milk-vetch species 

(Barneby, 1964). Within this genus, the large seeds are thought to be better adapted to active 

dunes than small seeds. This may be due to the larger food reserves enabling them to emerge 

even when deeply buried (Bowers, 1996). Harper et al. (1970), however, noted that there is a 

trade-off between seed size and seed numbers such that large-seeded plants typically produce 

fewer seeds. Peirson’s milk-vetch seeds are transported within inflated pods that are 

dispersed by winds across the dunes where they may come to rest within vegetation or 

depressions. Many seeds fall prey to members of the seed beetle family, Bruchidae. This 

contributes to a high mortality of seeds and reduced seed crop for this species (Romspert and 

Burk, 1979).

Peirson’s milk-vetch habitat consists of sandy depressions at the base of high dunes and 

lower established dunes. This species does not extend many lateral roots and, therefore, is 

more vulnerable if the main stem is broken. The vulnerability of the adult plants in 

conjunction with the period of seedling establishment during the cooler months, which 

coincides with the higher usage of the dunes by OHVs, makes this species sensitive to 

impacts (Romspert and Burk, 1979).

Distribution and Occurrence within the Plan Area

Peirson’s milk-vetch, an obligate psammophyte, grows on the slopes and hollows of 

windblown dunes in the Colorado and Sonoran deserts. According to Barneby (1964) and 

Wiggins (1980), it is known from the Imperial Sand Dunes. Additionally, the milk-vetch is 

known to occur in the Gran Desierto in Sonora, Mexico (Felger, 2000). Although it has been 

reported from Borrego Valley, San Diego County, California, it has not been observed there 

for several decades (Tibor, 2001).

The only location where the Peirson’s milk-vetch is currently known to occur within the 

United States is the Imperial Sand Dunes, which supports between 75 and 80 percent of all of 

the world’s known colonies of the species (Federal Register, 1998). The milk-vetch is 

associated with psammophytic scrub habitat within these dunes. The plant is generally 

scattered throughout the dune complex with a higher abundance of the plant along the central 

and western aspect of the Imperial Sand Dunes. Figure 3.2-2 depicts the distribution and 

abundance of this species at the ISDRA.
114

Threats

OHV use and associated recreational development have been described as the primary threat 

to Peirson’s milk-vetch through destruction of individual plants and habitat (Luckenbach and 

Bury, 1983; ECOS, 1990; Federal Register, 1998). However, recent monitoring indicates 

that the response of Peirson’s milk-vetch is closely tied to precipitation. It was most 

abundant in years with the highest rainfall and least abundant in years with the lowest 

rainfall. Response of Peirson’s milk-vetch was similar in areas both open and closed to OHV 

use. (Willoughby 2001)

Algodones Dunes Sunflower (Helianthus niveus ssp. Tephrodes)

Status

The Algodones Dunes sunflower was listed as endangered by the State of California in 

November 1979. It is recognized by the CNPS as 1B (rare, threatened, or endangered in 

California and elsewhere throughout their range).

Life History

The Algodones Dunes sunflower (also commonly referred to as the Algodones sunflower and 

the silver-leaved dune sunflower) is a perennial herb and native to California. A dense 

covering of fine hairs protects the plant from excess light and heat, (a common dune plant 

adaptation), and gives the leaves a silvery appearance (BLM, 1987). The Algodones Dunes 

sunflower is a relatively long-lived species; and, once established, it is able to survive periods 

of below-average precipitation. Felger (2000) reports that the species is 1.5 to over 3 feet tall, 

occasionally to 9 feet. Like Peirson’s milk-vetch, Algodones Dunes sunflower has relatively 

large seeds and is fast growing. 

Distribution and Occurrence within the Plan Area

The Algodones Dunes sunflower tends to grow in areas with active sand movement, such as 

on the lower portion of dune slip faces. The Algodones Dunes sunflower has been observed 

thriving where no other vegetation occurs on actively moving sand; but it also can be 

frequently associated with swales where concentrations of other vegetation are found (TOA, 

2001). Figure 3.2-3 depicts the distribution and abundance of this species at the ISDRA.

Threats 

At the ISDRA, the primary threat to Algodones Dunes sunflower is destruction of individual 

plants and habitat by OHV use and associated recreational development.

Wiggins’ Croton (Croton wigginsii)

Status

Wiggins’ croton was recognized by the State of California as rare in January 1982 

(CNDDB, 2001). It is also recognized by the CNPS as Category2 (plants rare, threatened, or 

endangered in California, but common elsewhere in their range).

Life History

Wiggins’ croton is a many branched, woody perennial, which grows from 20 to 30 inches high.
115

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Peirson’s Milk-vetch Distribution - 126Kb 
116

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117

View Figure 3.2-3

Algodones Dunes sunflower distribution - 89Kb 
118

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119

Distribution and Occurrence within the Plan Area

This species is native to California, Arizona, and from Baja California and Sonora, Mexico. 

In the Imperial Sand Dunes it is found within psammophytic scrub habitat and prefers 

stabilized and partially stabilized desert dune systems (CNDDB,2001). It most often grows 

on south or southeast slopes of basins, and sometimes grows farther toward the floor of the 

basin (TOA, 2001). Figure 3.2-4 depicts the distribution and abundance of this species at the 

ISDRA.

Threats 

At the Plan Area, the primary threat to Wiggins’ croton is destruction of individual plants and 

habitat by OHV use and associated recreational development.

Giant Spanish Needle (Palafoxia arida var. gigantea)

Status

The giant Spanish needle is recognized by the BLM as a sensitive species. The CNPS lists 

the giant Spanish needle as Category 1B (rare, threatened, or endangered in California and 

elsewhere throughout their range).

Life History

Giant Spanish needle is a fast-growing annual found on active sand dunes. This dune species

tends towards gigantism, with larger and more robust plants than related non-dune taxa (Felger, 

2000). Felger (2000) reports it growing from 2 to 5 feet tall.

Distribution and Occurrence within the Plan Area

This species is native to California and is found from California to Arizona and in Sonora, 

Mexico (BLM, 1987; TOA, 2001). Once established, giant Spanish needle is able to survive 

periods of below-average precipitation. Abundance of giant Spanish needle in a given year is 

almost unrelated to the precipitation of the immediately preceding growing season (BLM, 

2001a). As a short-lived flowering perennial, it frequently occurs within the Imperial Sand 

Dunes in sites with milk-vetch and croton (BLM, 2001a; TOA, 2001). Most of its 

occurrences were south of the large enclosure south of I-8 (TOA, 2001). Figure 3.2-5 depicts 

the distribution and abundance of this species at the ISDRA.

Threats 

At the Plan Area, the primary threat to giant Spanish needle is destruction of individual 

plants and habitat by OHV use and associated recreational development.

Sand Food (Pholisma sonorae)

Status

This species is recognized by the BLM as a sensitive species. The CNPS lists this species as 

Category 1B (rare, threatened, or endangered in California and elsewhere throughout their 

range).

Life History

This parasitic, perennial herb is native to California. As a root parasite, most of the plant is 

buried in the sand and only the flower heads are visible aboveground. This species is 

parasitic on Tiquilia plicata, Eriogonum deserticola (Armstrong, 1980) and possibly also on 

Croton wigginsii (Westec, 1977). The point of connection with the host plant may be more 

than a yard below the surface. Sand food stems are succulent and store copious amounts of 
120

water. During times of drought, it may provide moisture to the host plant. It is visible 

aboveground for only a short time. Each spring, a flowering stem is sent to the surface by the 

sand food, which produces a disk-shaped inflorescence with hundreds of tiny pink flowers. 

Sand deflation does not seem to affect its flowering (TOA, 2001).

 The primary habitat of sand food is open, sandy flats and sandy or stony desert washes 

within creosote bush scrub (CNDDB, 2001). Sand food was found at scattered locations 

during the Thomas Olsen and Associates (TOA) survey, most commonly in the Gecko Road 

area and the area just south of the large interim closure. It was generally in somewhat flat 

areas, but its appearance was difficult to predict, as there were many sites with hosts but 

without sand food (TOA, 2001). Figure 3.2-6 depicts the distribution and abundance of this 

species at the ISDRA.

Threats

At the Plan Area, the primary threat to sand food is destruction of individual plants and 

habitat by OHV use and associated recreational development. Additionally, impacts to host 

plants would have a negative effect on the sand food population (BLM, 2001a).

Relevant Reports

BLM Monitoring Report

In 1998, the BLM initiated monitoring of the six rare plant species. Monitoring was 

conducted in spring and summer 1998, spring 1999, spring 2000, and spring 2001. Results of 

the spring 2001 survey are not currently available. Utilizing the Westec study methodology 

(discussed later in this section), the dunes were divided into four geographic strata, 34 of the 

original 66 transects were randomly selected from those strata and divided into cells. 

Numbers of rare plants were then recorded within 10 to 15meters or fixed parallel transects 

in each of the cells. Abundance classes were assigned for each species in a cell (BLM, 

2000a). This report compared the responses of the six rare plant species, as measured by 

abundance class data, over all 4 years of monitoring (1977 and 1998-2000). The study 

concluded that plants are at least as abundant and widespread in the entire dune system as 

they were in 1977. This report also noted that healthy populations of all six species remain in 

areas open to recreation, although the aboveground expression of populations of some of 

these species dramatically fluctuates with precipitation (BLM, 2001a).

The following is a species-by-species summary of the BLM monitoring study:

Peirson's milk-vetch. Abundance was closely tied to precipitation throughout the 

four years of monitoring. Species abundance was highest in 1998, second highest in 

1977, third highest in 1999, and lowest in 2000. This mirrors the ranking of the four 

growing seasons in terms of average precipitation. Recruitment was possibly high in 

1998 and low to nonexistent in 1999 and 2000. Responses of this species were similar 

in both the closed and open recreation areas across all 4 years of monitoring. 

Algodones Dunes sunflower. Abundance increased significantly between 1977 and 

1998. This increase is the result of a large increase in the values for the open area 

between 1977 and 1998. There were only slight decreases in abundance for 1999 and 

2000. Between 1977 and 1998, the species declined in abundance in the closed area. 

This could be the result of lower recruitment of individuals into the population in the 
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Wiggins’ Croton Distribution - 82Kb 
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View Figure 3.2-5

Giant Spanish Needle Distribution - 96Kb 
124

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125

View Figure 3.2-6

Sand Food Distribution - 73Kb
126

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127

closed area. With the exception of 1977, the responses in the open and closed areas 

were parallel. 

Wiggins’ croton. Abundance in 1977 was about half of 1998. Abundance for 1999 

and 2000 was similar to 1998. This increase may represent a real increase in the 

population size of this species in the dune system. Most of this increase was 

detected in the open area. Comparison of abundance in the closed and open areas 

indicate that except for 1977, when abundance was similar for both areas, the 

abundance for the rest of the years showed that open areas consistently had higher 

abundance.

Giant Spanish needle. Abundance was highest in 1998, the best rainfall year. 

However, abundance was second highest in 2000, the lowest rainfall season. The 

reason for the relatively high abundance in 2000 was unclear. Based on rainfall, it 

was expected that 1977 would have the second highest abundance. Instead, 1977 

abundance ranked third and 1999 ranked last. The abundance between closed and 

open areas is very similar for 1977, 1998, and 1999, with 2000 having more 

abundance in the closed area. Data also appear to indicate that this species is more 

common in the northern part of the dunes, independent of whether the area is closed 

or open.

Sand food. Abundance increased between 1977 and 2000, with the highest 

abundance registered for 2000, the worst rainfall year. The reason for the relatively 

high abundance in 2000 was unclear. The second highest abundance was 1998, and 

1999 abundance was very close to 1998. Abundance for this species in closed and 

open areas was the same for 1999. In 1998 and 2000, the values for the closed areas 

were higher than open areas. However, this determination may have been due to a 

limitation in the survey method. In 1998, 1999, and 2000, transects were conducted 

on foot in the closed area, while those in the open area were run from a dune buggy. 

Additionally, in 1977, closed areas had lower abundance than open. This, too, may 

have been due to a limitation in the survey method. The 1977 survey utilized a 

helicopter in closed areas, not the ideal survey method to detect this cryptic plant. 

Borrego milk-vetch. Abundance was essentially the same in 1977 and 1998. No 

plants at all were found in either 1999 or 2000, a statistically significant decline from 

1998 and 1977 levels. Presumably, precipitation was insufficient for growth and 

establishment in 1999 and 2000. No comparison of abundance between closed and 

open areas was made because this taxon did not occur in the closed area.

Thomas Olsen and Associates Report

In 2001, the American Sand Association (ASA) retained the services of Thomas Olsen and 

Associates to provide an independent assessment of the abundance, distribution, and life 

history of the Peirson's milk-vetch at the Imperial Sand Dunes. Additional distribution and 

abundance data were also collected on five other rare plants. As opposed to the BLM 

monitoring study, this study was designed to obtain an actual census of Peirson’s milk-vetch. 

The other five plant species were also counted when they were observed with Peirson’s milkvetch. A nonprobabilistic survey was employed to determine areas for survey. As a first step 

in the survey methodology interviews of OHV users, BLM staff, and Border patrol officers 

who were familiar with the project area were conducted to determine locations of Peirson's 
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milk-vetch. The second step included a general reconnaissance of the entire dune areas 

outside the interim closures and wilderness area. The third step consisted of actual intensive 

surveys of specific areas based on professional knowledge of habitat requirements of species, 

reconnaissance information, and feedback from the interviewees (TOA, 2001). 

The team surveyed by foot and rail within the open areas. When a substantial number of 

plants were detected, the area was designated as a “site.” A number was assigned to each site, 

and a team of two to three biologists conducted a census of the plants and recorded other 

habitat characteristics. Areas that were too small to circumscribe on a map or contained a 

small number of plants were designated as "points.” Additionally, the team conducted an 

aerial survey by helicopter of the interim closure areas. Parallel transects or concentric 

circles of decreasing diameter were flown within each of the closure area boundaries south of 

SR-78 and a portion of the North Algodones Dunes Wilderness Area north of the highway.

The survey produced a total of 61 sites and 66 points containing one or more of the rare 

plants within the dunes. Notable concentrations were found in several areas, which included: 

(1) the southern portion of the dunes near the international border and west of Buttercup 

Valley; (2) the area near Patton Valley, south of the large closure and west of the dune peaks; 

(3) between the small central closure and the large central closure; and (4) the east side of the 

small central closure.

The general conclusion from this study was that the distribution of the rare plants is 

dependent on the geomorphology of the dunes, and they tend to be concentrated in areas 

where there is relative substrate stability. These are areas located generally on the lee side of 

the large dunes, in areas where the surface gradually slopes upwards from deep or shallow 

basins at the base of steep slipfaces. The study also concluded that less than 1 percent of 

the plants had been affected by OHVs (TOA, 2001).

The following is a species-by species summary of the TOA study:

Peirson's milk-vetch. A grand total of 71,926 individual plants were recorded. 

Occurrences were clustered in general areas, and no milk-vetch was detected in large 

portions of dunes. Generally, they were found west of the primary dunes in the open 

areas. The greatest number of plants found at a single site was 3,994 in the southern 

border area.

Algodones Dunes sunflower. This species was detected in 31 of 61 Peirson’s milkvetch sites, for a total count of 1,289, scattered throughout the primary dunes. The 

greatest estimated number of plants at a single site was 431 individuals.

Wiggins' croton. This species was found at 52 of 61 Peirson’s milk-vetch sites for a 

total count of 3,614. They were found evenly distributed throughout the open areas, 

sharing generally the same habitat as the milk-vetch.

Giant Spanish needle. This species was found at 47 of 61 Peirson’s milk-vetch sites 

for a total count of 4,191 individuals. Most of the occurrences were south of the 

Central Closure #2 and south of I-8.

Sand food. A total of 65 plants were found at nine scattered sites and points, most 

notably in the Gecko Road area and the area just south of Central Closure #2.
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Borrego milk-vetch. The preferred habitat at the Plan Area for the Borrego milkvetch, which is on the eastern portion of the dune system, was generally not surveyed 

during this study. However, a single site with 15 individuals was detected on the 

eastern edge of the dunes.

Westec Services, Inc. Report 

Westec Services, Inc., carried out the initial survey of rare plants in the Imperial Sand Dunes 

under contract with the BLM in 1977. They surveyed for eight rare plants, of which seven 

were found. To determine species abundance, Westec surveyed 66west-east, randomly 

selected parallel transects that were segmented into cells 0.45-mile per side (Westec, 1977). 

It must be noted that the Westec study was not specifically designed to study OHV impacts, 

and the conclusions are based on a single-year study. The study offered the following 

conclusions:

- Seedlings of rare species could not be found in “high impact areas,” while seedlings 

of these species were abundant in other areas of the dunes.

- Intensity of OHV use in the dunes appears to be the key factor in impacting dune 

vegetation. Greatest impact occurs within the heaviest use areas.

- Lower level of “secondary impact” occurs throughout the dunes. However, this 

sporadic impact appears to decrease with increasing distance from the center of high 

impact areas.

- Despite the observed impacts, healthy reproducing populations of all rare plant 

species occurred within the dunes.

Luckenbach and Bury Report 

In 1983, the Luckenbach and Bury study conducted at the Imperial Sand Dunes is perhaps 

one of the most significant studies that systematically addressed OHV impacts to the dune 

biota. However, the study has limited utility toward drawing conclusions with respect to rare 

plants since most of the study plots had none of these species in them. Another limitation is 

that the study compared sites with heavy OHV use to sites with no OHV use, which does not 

allow inferences to be made to less heavily used OHV sites. Also, what data were collected 

showed that Peirson’s milk-vetch density and cover were actually higher in the OHV area 

than in the closed, control area. The following are the conclusions of this study:

- OHV activities in the dunes are highly detrimental to dune biota.

- Both herbaceous and shrubby perennial vegetation is reduced greatly in areas where 

OHVs operate.

- Most commonly, plants were destroyed by direct destruction or damage to root 

systems of psammophytic shrubs.

- Changes due to OHV impacts may result in substrate changes, such as compaction, 

reduced porosity, altered thermal structure, and reduced moisture content, although 

these effects were not tested.
130

ECOS, Inc. Report

In 1990, Ecos, Inc. was contracted by BLM to perform habitat characterization and rare plant 

species analysis as well as design a long-term monitoring plan. This study did not count the 

total number of plants; instead, they analyzed population fitness by scoring a set of variables 

for each species. This study concluded that substantially less vegetative cover and species 

diversity was observed. However, a limitation of this study is that it was conducted in a year 

of severe drought and study sites in the open OHV area were located relatively close to OHV 

staging areas. Therefore, the observations on OHV impacts to plant species do not apply to 

most of the OHV open area. 

Special-Status and Endemic Wildlife Species

The designation of special-status includes federal- and state-listed species under either the 

federal or California ESA, species proposed for federal listing, federal candidate species, and 

species designated as sensitive by the California State Director of the BLM. The following 

special-status wildlife and endemic beetle species are known or may occur within the Plan 

Area. Therefore, these species may be affected by the planned action. Descriptions of these 

species are provided below.

Desert Tortoise (Gopherus agassizii)

Status

The Mojave population of the desert tortoise was emergency listed by the USFWS as an 

endangered species in 1989. Under final rule, the species was federally listed as threatened in 

1990 (Federal Register, 1990). The State of California listed this species as threatened in 1989. 

The BLM recognizes the desert tortoise as a special-status species. Currently, the BLM is 

completing or has recently completed several management plans including the West Mojave 

Coordinated Management Plan (WEMO), Northern and Eastern Mojave Coordinated 

Management Plan (NEMO), and Northern and Eastern Colorado Coordinated Management Plan 

(NECO) (BLM, 2001a). An important focus of these plans is the management of the Mojave 

population of the desert tortoise and its habitat on BLM lands in California. A final recovery 

plan was completed by the USFWS in 1994 for the Mojave population of the desert tortoise 

(USFWS, 1994). Critical habitat for the Mojave population was also designated by the 

USFWS in 1994 (Federal Register, 1994). The Chuckwalla Bench Critical Habitat Unit for 

this species is located approximately 20 miles northeast of the ISDRA. 

Life History

The desert tortoise is a large herbivorous terrestrial reptile. It has a high domed shell that may 

reach a length of 15 inches or more. This species has stocky, elephant-like limbs and a short 

tail. The carapace (upper shell) is brown; and the plastron (lower shell) is yellow in color, 

both exhibiting prominent growth lines. Adult males can be distinguished from females by 

the concavity in their plastron. Adult males also have larger chin glands and a longer tail and 

gular horn than females (Stebbins, 1985). 

The adult desert tortoise is active from mid-March or April to November, and during the 

winter months is dormant in underground burrows (Luckenbach, 1982; Zimmerman et al., 

1994). Desert tortoises will congregate in winter dens during colder weather, then spread out 

to nearby areas during moderate weather in the spring and fall and retreat into short 

individual burrows or under shrubs during more the extreme heat of the summer (Woodbury 

and Hardy, 1940). During the active period, desert tortoises may establish home ranges of 
131

approximately 1 square mile. Tortoises feed on a wide variety of herbaceous plants, 

including cactus, grasses, and annual flowering plants (USFWS, 1994).

Adult desert tortoises reach sexual maturity at 15 to 20 years of age. Mating occurs in the 

spring (April and May) and the fall (August and September) with nesting and egg laying 

occurring from May to July (Rostral et al., 1994). The female tortoise lays her eggs in a hole 

approximately 3 to 4 inches deep that is dug near the mouth of a burrow. Following egg 

laying the female covers the eggs with soil (Woodbury and Hardy, 1948). Clutch size ranges 

from 2 to 14 eggs with an average of 5 to 6 eggs (Luckenbach, 1982). Desert tortoise eggs 

typically hatch from August through October. These hatchlings are provided a food source 

in the form of an egg yolk that is assimilated into the underside of the shell. This yolk sac 

will sustain the animal for up to 6 months. The hatchling desert tortoise will go into 

hibernation in the late fall, but can be active on warm sunny or rainy days.

Distribution and Occurrence within the Plan Area

The desert tortoise is widely distributed throughout the Mojave, Sonoran, and Colorado 

deserts. It occupies arid regions from southern Nevada and extreme southwestern Utah to 

northern Sinaloa, Mexico; southwestern Arizona west to the Mojave Desert and the eastern 

side of the Salton Basin, California (Stebbins, 1985). 

In the Mojave region, desert tortoises are primarily associated with flats and bajadas with 

soils ranging from sand to sandy-gravel, but firm enough for the tortoise to construct burrows 

(USFWS, 1994). In California, the desert tortoise is most commonly found in association 

with creosote bush scrub with intershrub space for growth of herbaceous plants. However, it 

may also occur in saltbush scrub, desert wash, desert scrub, and Joshua tree woodlands. The 

desert tortoise is found from below sea level to elevations of 5,000 feet in California. The 

most favorable habitats occur at elevations of approximately 1,000 to 3,000 feet. 

Desert tortoise habitat in the general vicinity of the ISDRA has been degraded and 

fragmented by OHV and camping use, agricultural development, utility corridors, and the 

construction and maintenance of the railroad and All American Canal. Along the eastern 

boundary of the ISDRA, the creosote bush scrub habitat and the desert washes north and 

south of SR-78 provide marginal suitable habitat for the desert tortoise. BLM and Border 

Patrol officials have observed desert tortoises in the general vicinity of and crossing Vista 

Mine and Ted Kipf Roads. To date, limited surveys for desert tortoise have been conducted 

at the ISDRA. Limited desert tortoise distribution and abundance data currently exist. The 

BLM proposes to conduct surveys to collect such data on this species at a latter date. 

Threats

The decline in the desert tortoise population is attributed primarily to habitat loss, 

degradation, and fragmentation resulting from increased human population and urbanization 

in the desert and arid regions of the southwestern United States. The increase in 

urbanization, collection of tortoises for pets, overgrazing, landfills, subsidized predation, 

including predation by ravens, highway mortality, vandalism, agriculture, fire, drought, and 

OHV use all have contributed to the decline of the tortoise in the wild (Luckenbach, 1982; 

Federal Register, 1990). Another important reason for the decline of the desert tortoise is the 

introduction of an upper respiratory tract disease (URTD) into many of the wild populations 

(Berry, 1986). This disease was thought to have been introduced through the illegal release 

of captive desert tortoises into the wild (USFWS, 1994). 
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Flat-tailed Horned Lizard (Phrynosoma mcalli)

Status

In California, the flat-tailed horned lizard was designated a sensitive species by the BLM in 

1980. In 1988, a petition was submitted to the CFGC to list the species as endangered. In 

1989, the commission voted against the proposed listing. In 1993, the USFWS published a 

proposed rule to list the flat-tailed horned lizard as a threatened species (Federal Register, 

1993). No final rule on the proposed listing was issued. In 2001, the USFWS published a 

notice of reinstatement of the 1993 proposed listing of the flat-tailed horned lizard as a 

threatened species and reopened the comment period on the proposed rule (Federal Register, 

2001). Recently, USFWS withdrew the proposal to list the flat-tailed horned lizard. 

Currently, the State of California and BLM recognize the flat-tailed horned lizard as a 

species of special concern and special-status species, respectively.

Life History

The flat-tailed horned lizard has the typical flattened body shape of horned lizards. It is 

distinguished from other species in its genus by its dark ventral stripe, lack of external 

openings, broad flat tail, and comparatively long spines on the head (Funk, 1981). The flattailed horned lizard has two rows of fringed scales on each side of its body. The species has

cryptic coloring, ranging from pale gray to light rust brown dorsally and white or cream 

ventrally with a prominent umbilical scar. The only apparent external difference between 

males and females is the presence of enlarged postanal scales in males. Maximum snout-vent 

length for the species is 3.3 inches (Muth and Fisher, 1992). 

Flat-tailed horned lizards escape extreme temperatures by digging shallow burrows in the 

loose sand. Adults are primarily inactive from mid-November to mid-February. Juvenile 

seasonal activity is often dependent on temperature fluctuations. Breeding activity takes 

place in the spring with young hatching in late July and September. The diet of horned 

lizards typically consists of greater than 95 percent native ant species, mostly large harvester 

ants (Pogonomyrmex spp.). 

Distribution and Occurrence within the Plan Area

The flat-tailed horned lizard is found in the low deserts of southwestern Arizona, 

southeastern California, and adjacent portions of northwestern Sonora and northern Baja. In 

California, the flat-tailed horned lizard is restricted to desert washes and desert flats in central 

Riverside, eastern San Diego, and Imperial Counties. The majority of the habitat for the 

species is in Imperial County (Turner et al., 1980).

The lizard is known to inhabit sand dunes, sheets, and hummocks, as well as gravelly 

washes. The species is thought to be most abundant in creosote bush scrub habitat. However, 

this species may also be found in desert scrub, desert wash, succulent shrub, alkali scrub, 

sparsely vegetated sandy flats, desert pavement, and rocky slopes. They are typically found 

in dry, hot areas of low elevation (less than 800 feet). 

Suitable habitat for the flat-tailed horned lizard is found east of the project area from Ogilby 

Road and extending south to the All-American Canal (FERC, 2001). Monitoring conducted 

as part of the North Baja Pipeline Project in 2000 and 2001 detected flat-tailed horned lizard 

in this area (FERC, 2001). Rado noted that sand sheets extending east from the sand dunes 

provide favorable habitat for about 1 mile northwards from the intersection of Ogilby Road 

and I-8 (Rado, 1995). 
133

The surveys conducted by the BLM in 1978, 1979, and 1980 reveal that the highest 

abundance of this species occurs southwest of the ISDRA in the East Mesa ACEC. Low 

abundance of this species was detected on the eastern and western boundaries of the sand 

dunes, predominantly in the creosote bush scrub habitat. Although this species is known to 

occur in the central Imperial Sand Dunes, the habitat is considered to be marginal because of 

the lack of suitable soil structure required to support their predominant prey: harvester ants 

(BLM, 2001b). Figure 3.2-7 depicts the distribution and abundance of this species at the 

ISDRA.

Threats

Human activities have resulted in the conversion of approximately 34 percent of the historic 

habitat of the flat-tailed horned lizard. The decline in the flat-tailed horned lizard population is 

primarily due to impacts from utility lines, roads, geothermal development, sand and gravel 

mining, OHV use, waste disposal sites, military activities, pesticide use, and Border Patrol 

activities (Foreman, 1997). The Argentine ants (Linepithema humile), an invasive species, 

was considered as a threat and dismissed. The climate at the dunes is too dry for the 

Argentine ants to survive.

Colorado Desert Fringe-Toed Lizard (Uma notata)

Status

The Colorado Desert fringe-toed lizard is a federal candidate for listing and State of 

California species of special concern. It is also recognized by the BLM as a sensitive 

species.

Life History

The fringe-toed lizard is a flattened, sand-dwelling lizard with characteristic fringed toes. The 

species is cryptic in color ranging from a sand color dorsally and white or cream ventrally. It 

also has pronounced dark lines on the throat, underside of the tail, and sides of the belly. The 

sides of the belly may also have vivid orange streaks especially during the breeding season. 

The only apparent external difference between males and females is the presence of enlarged 

postanal scales in males. Maximum snout-vent length for the species is 4.8 inches (Stebbins, 

1985). 

This species escapes extreme temperatures by digging shallow burrows in the loose sand 

deposits, often in primary and secondary dunes at the base of bushes in psammophytic and 

creosote bush scrub habitats. Adults are primarily inactive from mid-November to midFebruary. Juvenile seasonal activity is often dependent on temperature fluctuations. 

Breeding activity takes place in the spring. This species primarily feeds on insects, but 

occasionally eats other lizards. They are also known to feed on buds, leaves, and flowers of 

plants. 

Distribution and Occurrence within the Plan Area

The range of this species is from the vicinity of the Salton Sea and Imperial Sand Dunes, 

south across the Colorado River Delta to the Gulf of California and Tepopca Bay in Baja 

California. The fringe-toed lizard is largely restricted to fine, loose, wind-blown sand of 

dunes, flats, riverbanks, and washes. Vegetation is usually sparse, consisting of creosote 

bush or psammophytic scrub. The Colorado Desert fringe-toed lizard is known to occur 
134

within the Plan Area. To date, the BLM has conducted several surveys for fringe-toed 

lizards at the ISDRA. Figure 3.2-8 depicts the distribution and abundance of this species at 

the ISDRA.

Threats

Threats to Colorado fringe-toed lizard populations are similar to those described for the flattailed horned lizard. 

Couch’s Spadefoot Toad (Scaphiopus couchi)

Status

Couch’s spadefoot toad is recognized by the State of California as a species of special 

concern and as a sensitive species by the BLM. 

Life History

The Couch’s spadefoot toad is distinguished from true toads by its cat-like eyes, single sharpedged black spade on its hind foot, teeth in the upper jaw, and rather smooth skin. The pupils 

of this species are vertical in bright light and round at night. Couch’s spadefoot toad is 

greenish yellow to brownish yellow with an irregular network of dark blotches dorsally and 

generally whitish ventrally. Males generally have a dusky throat, dark nuptial pads on the 

innermost front toes, and are often more greenish than the females. Their voice is a plaintive 

cry or groan, declining in pitch like the anxious bleat of a sheep (Stebbins, 1985). 

They are generally active at night during spring and early summer rains and can be found in 

temporary desert rain pools with an insect food base available. Breeding is primarily from 

May-September during rainfall periods. They require friable soil for burrowing where they 

typically spend up to 11 months underground until sufficient rainfall has occurred. 

Distribution and Occurrence within the Plan Area

The Couch’s spadefoot toad occupies a variety of habitat types, including desert dry wash 

woodland, creosote bush scrub, desert riparian, palm oasis, desert succulent scrub, shortgrass 

plains, mesquite savannah, and alkali sink scrub. In California, the Couch’s spadefoot toad 

occurs within Imperial, Riverside, and San Bernardino Counties between 500 to 3,000 feet 

elevation. Scattered populations are known between Amos and Ogilby on the eastern 

boundary of the Imperial Sand Dunes. This species may occur in the microphyll woodland, 

desert dry wash, and creosote bush scrub habitats in the eastern portion of the Plan Area. To 

date, the BLM has not conducted any surveys for this species at the ISDRA. Therefore, 

Couch’s spadefoot toad distribution and abundance data do not currently exist.

Threats

No specific threats to Couch’s spadefoot toad are known. Potential threats to this species 

include loss, fragmentation, or degradation of habitat.

Gila Woodpecker (Melanerpes uropygialis)

Status

The Gila Woodpecker is listed as endangered by the State of California. It is also recognized 

by the BLM as a special-status species.

Life History

The Gila Woodpecker is a “zebra-backed” woodpecker. The males have a red cap on top of 

their head. The head and under parts are typically gray-brown. The Gila Woodpecker feeds 
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View Figure 3.2-7

Flat Tailed Horned Lizard Distribution - 117Kb 
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137

View Figure 3.2-8

Colorado Fringe-toed Lizard Distribution - 77Kb
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mainly on insects, mistletoe berries, cactus fruits, corn; and occasionally contents of galls on 

cottonwood leaves, bird eggs, acorns, and cactus pulp. The species breeds from April 

through July, with peak activities in April and May. They are cavity nesters and may use 

abandoned owl cavities. 

Distribution and Occurrence within the Plan Area

The Gila Woodpecker’s preferred habitat is mesquite-dominated microphyll woodlands and 

desert dry washes. They also occupy orchard-vineyards (specifically, date palm groves) and 

urban areas (shade trees). This species was formerly prolific throughout the Imperial Valley. 

Due habitat degradation, most of the current populations are concentrated in the Brawley, 

California area (CDFG, 2001). Brawley is located approximately 20 miles west of the Plan 

Area. At the Plan Area, this species may occur in the microphyll woodland habitat on the 

eastern side of the Imperial Sand Dunes. To date, the BLM has not conducted any surveys for 

this species at the ISDRA. Therefore, Gila Woodpecker distribution and abundance data do 

not currently exist.

Threats

Loss, fragmentation, or degradation of riparian woodland to development has displaced the 

woodpecker from some areas. Additionally, European Starlings are competing with this 

species for nest cavities (CDFG, 2001). 

Burrowing Owl (Athene cunicularia)

Status

This species is recognized by the State of California as a species of special concern and as a 

sensitive species by the BLM. 

Life History

This species of owl is identified by its barred and spotted plumage, white chin stripe, round 

head, and stubby tail. The Western Burrowing Owl is a diurnal (daylight active) species that 

is non-migratory in this portion of its range. Burrowing Owls are opportunistic feeders, 

preying upon arthropods, small mammals, birds, and sometimes reptiles and amphibians.

This species breeds from late April through July in the Imperial Valley. Burrowing owls are 

subterranean nesters, typically found using burrows made by small mammals such as ground 

squirrels and badgers. The Burrowing Owl commonly perches on fence posts or on top of 

mounds outside its burrow.

Distribution and Occurrence within the Plan Area

Found throughout much of the western United States, this species inhabits open, dry 

grasslands, deserts, agricultural areas, and scrublands characterized by low growing 

vegetation. These owls also occupy open areas of airports, golf courses, and vacant urban 

lots. They are generally found at elevations ranging from 200 feet below sea level to 9,000 

feet. Throughout the Imperial Valley, burrowing owls are frequently found along unlined 

agricultural canals and drainages. It is typically found in low densities in desert habitats, but 

can occur in much higher densities near agricultural lands where rodent and insect prey is 

more abundant. There are no known records of this species at the Plan Area. The 

psammophytic habitat is not suitable for this species. However, the creosote bush scrub and 

microphyll woodland habitats on the eastern boundary of the Imperial Sand Dunes are 

suitable for Burrowing Owls. To date, the BLM has not conducted any surveys for this 
140

 species at the ISDRA. Therefore, Burrowing Owl distribution and abundance data do not 

currently exist.

Threats

Threats to this species include habitat degradation, disturbance to nesting and roosting sites, 

and pesticides and other contaminants/toxins. Agricultural practices that reduce the ground 

squirrel population result in a reduction of the available nesting and roosting sites for the 

Burrowing Owl. 

LeConte’s Thrasher (Toxostoma lecontei)

Status

This species is recognized by the State of California as a species of special concern and as a 

sensitive species by the BLM. 

Life History

The LeConte’s Thrasher is pale gray-brown in color, with a long tail, and recurved bill. They 

typically run before taking flight. LeConte’s Thrashers feed on seeds, insects, small lizards, 

and other small vertebrates. This species requires areas with an accumulated leaf litter that 

serves as cover for its primarily arthropod prey. Only during breeding activities, when males 

sing from exposed perches, are they relatively easy to detect. 

Distribution and Occurrence within the Plan Area

LeConte’s Thrasher is a desert resident of areas with sparse desert scrub, alkali desert scrub, 

and desert succulent scrub habitats with open desert washes (CNDDB, 2001). It is found 

year-round throughout much of the Mojave and Colorado Deserts of California. Population 

densities of this species are among the lowest of passerine (perching) birds, estimated at less 

than five birds per square mile in optimum habitat. At the ISDRA, the creosote bush scrub 

habitat and the desert washes on the eastern side of the Plan Area may provide suitable 

habitat for the LeConte’s Thrasher. To date, the BLM has not conducted surveys for this 

species at the ISDRA. Therefore, LeConte’s Thrasher distribution and abundance data do 

not currently exist.

Threats

OHV activity and other human disturbance are considered disruptive to this species, 

especially during the breeding season (late January to early June). OHV use can crush 

vegetation and destroy the underlying litter and soil surface thereby precluding heavily used 

sites from further use by this species (Sheppard, 1996).

Andrews’ Dune Scarab Beetle (Psuedocotalapa andrewsi)

Likely endemic to the Imperial Sand Dunes, Andrews’ dune scarab beetle is found primarily 

along the eastern edge of the dunes in the transitional zone between creosote bush scrub, 

psammophytic scrub, and microphyll woodland habitats. Little is known about the biology 

of this beetle. Current information about the distribution and preferred habitat at the Plan 

Area is not available (CNDDB, 2001). There are no confirmed host plants identified of the 

Andrews’ dune scarab beetle. However, the adults of this species are known to swarm 

around creosote bushes, and may utilize the subsurface wet sand to regulate body 

temperature during the day (CNDDB, 2001). No information about threats to this species is 

available. 
141

Carlson’s Dune Beetle (Anomala carlsoni)

The Carlson’s dune beetle is likely endemic to the Imperial Sand Dune system; however, 

there is limited information available about the microhabitat requirements or basic biology of 

this species (CNDDB, 2001). The adult beetle is known to be active at dusk, generally on 

north- or east-facing slip faces. Generally, it seeks the transitional zone between creosote 

bush scrub, psammophytic scrub, and microphyll woodland habitats. Although there is no 

known host plant, the adult beetle has been sifted (collected) from a wide variety of plants 

(CNDDB, 2001). No information about threats to this species is available. 

Hardy’s Dune Beetle (Anomala hardyorum)

Hardy’s dune beetle is likely endemic to the Imperial Sand Dunes and is found primarily in 

the eastern portion of the ISDRA. The adult beetle is known to be active at dusk, generally 

on north- or east-facing slip faces. Generally, it seeks the transitional zone between creosote 

bush scrub, psammophytic scrub, and microphyll woodland habitats. The beetle also inhabits 

troughs of loose, drifting sand between the dune crests (BLM, 1987). Although there is no 

known host plant, the adult beetle has been sifted (collected) from a wide variety of plants 

(CNDDB, 2001). No information about threats to this species is available.
142

3.3 Law Enforcement and Public Safety

Introduction

United States Congress recognized that law enforcement on BLM-managed public lands was 

needed to encourage public safety and to protect resources. In 1976, BLM was given law 

enforcement authority with the passage of FLPMA. BLM law enforcement officers are 

responsible for promoting public safety and protecting resources within the 264 million acres 

of BLM-managed public land in the U.S. BLM officers accomplish this in partnership with 

other federal, state, and local law enforcement agencies. BLM El Centro law enforcement 

officers patrol the ISDRA, and are tasked with a variety of services, including: educating the 

public on the rules and regulations, providing security at recreation sites, preventing theft of 

and damage to biological and cultural resources, assisting in emergency response situations, 

enforcing the rules and regulations through the issuing of warning and citations and by 

making arrests. BLM El Centro law enforcement officers enforce both state and federal 

regulations in the dunes. Current statistics for recorded incidents at ISDRA, as well as 

summary of the law enforcement personnel are discussed below.

Recorded Incidents

Emergency Response - Medical Aid and Fatalities

During the 2000-2001 Visitor Season, approximately 147 incidents that required medical aid 

occurred over the six major holiday weekends. This represents an average of 25medical aid 

incidents per major holiday weekend. Based on an average of 55,000 visits per major 

holiday weekend (attendance can swell to over 100,000 visits during Thanksgiv ing 

weekend), approximately 1 reported medical aid incident occurs per 2,200 visitors. The 

number of fatalities averaged approximately one per busy holiday weekend during the 2000-

2001 Visitor Season. Table 3.3-1 lists a summary of documented medical aid responses and 

fatalities (1995 to 2001) provided by BLM El Centro. Records prior to 1995 are not 

available, and medical aid has not been fully documented over the years. The numbers 

shown in Table 3.3-1 do not fully capture each time aid was provided by BLM staff (BLM, 

2001d).

Table 3.3-1 Documented Medical Aid Responses and Fatalities: 1995 to 2001 –

Imperial Sand Dunes Recreation Area

Year Documented Medical Aid Responses Documented Fatalities

1995 165 0

1996 131 0

1997 210 5

1998 176 8

1999 151 5

2000 145 6

2001 147 8

Source: Hamada, 2001 – Personal Communication from Neil Hamada/BLM – El Centro to 

Elizabeth Cutler/CH2M HILL, October 30, 2001 – BLM unpublished data.
143

Citations and Arrests

During the 2000-2001 Visitor Season, approximately 3,530 citations/arrests occurred over 

the six major holiday weekends. On average, this represents approximately 588citations 

and/or arrests per major holiday weekend or 1.1 citations/arrests per 1,000 visits. The largest 

numbers of law enforcement incidents occur in Gecko Campground and Garbage Flats 

(BLM, 2001g). 

Violation notices tracked by BLM El Centro include the following categories: registration, 

minor in possession, no helmet, double riding, no lights, resisting arrest, open container, no 

safety flag, closed area, vendor permit, controlled substance, use fee, ride in pickup bed, 

natural feature destruction, speeding, possession of marijuana, furnishing alcohol to minor, 

revoked license, dumping, glass container, creating a hazard, litter, and concealed (loaded) 

firearm.

Arrests tracked by BLM El Centro include the following categories: DUI, assault, felony 

evade, warrant, drugs, explosive device, inciting riot, false information, auto theft, possession 

of stolen property, and interference.

Reports (including accidents) tracked by BLM El Centro include the following: assault, 

stolen vehicle, weapon in vehicle, drugs seized, accidents, felony hit and run, child 

endangerment, undocumented migrant detainees, resisting arrest, resisting issuance of a 

violation, abandoned vehicles, seized marijuana, seized marijuana/paraphernalia, vehicles 

towed, vehicles seized, and train accidents.

Table 3.3-2 provides a summary of violation notices, arrests, and reports (including 

accidents) that BLM El Centro issued for the six major holiday weekends during the 2000-

2001 season.

Table 3.3-2 Total Violation Notices, Arrests, and Reports Including Accidents During 

Major Holiday Weekends: 2000 -2001 – Imperial Sand Dunes Recreation Area

Holiday Weekend Number of Incidents

Halloween – 2000 260

Thanksgiving – 2000 1,501

New Year’s – 2001 409

Martin Luther King – 2001 191

Presidents Day – 2001 860

Easter – 2001 308

Source: BLM unpublished data, 2001.

Law Enforcement Personnel

The BLM, El Centro Field Office, has a staff of 12 delegated law enforcement officers (one 

Chief, two Supervisors, and nine Rangers) and two non-delegated law enforcement officers 

(trainees) any of whom may conduct regular patrols of the ISDRA. Various vehicles (e.g., 

quadrunners and dune buggies) are used to patrol the interior of the dunes to monitor OHV 

use. Most visitors stay within 1 mile of paved roads and the Sand Highway; however, with 
144

the increased use of global positioning system units, visitors are starting to venture further

into the inner dunes (BLM, 2001h).

Additional staffing resources include BLM staff from other offices, as well as other federal 

and state agencies including National Park Service (NPS), USFWS, U.S. Border Patrol 

(USBP), U.S. Forest Service (USFS), State Parks, California Highway Patrol (CHP), 

Imperial County Sheriff’s Department, Imperial City Police Department, Brawley Police 

Department, El Centro Police Department, Calipatria Police Department, and Calexico Police 

Department. These additional resources are typically brought in over the six major holiday 

weekends (Halloween, Thanksgiving, New Year’s, Martin Luther King, Presidents Day, and 

Easter). Some additional staffing resources are delegated law enforcement officers; others do 

not have the authority to arrest, but are capable of detaining individuals until delegated law 

enforcement officers can arrive. The Imperial County Sheriff’s Department and BLM 

currently co-lead law enforcement activities for major holiday weekends. The Imperial 

County Sheriff’s Department provides an average of 20 officers on holiday weekends and 

several deputies on non-holiday weekends.

BLM El Centro, Law Enforcement, determines the number of law enforcement officers 

needed for each holiday weekend to provide services for the ISDRA Plan Area based on the 

estimated visitor supply. They then coordinate with other agencies to arrange for the 

officers.

Public Safety Facilities and Equipment

The BLM, El Centro Field Office, has one permanent ranger station within the dunes area: 

Cahuilla Ranger Station is located on Gecko Road, within the most heavily visited area. The 

ranger station is open approximately 14 hours each day during holiday periods 

(approximately 20 days per year). On non-holiday weekends, the ranger station is open 

approximately 8 hours per day.

Additionally, during holiday weekends, two temporary contact stations are set up, one in 

Dune Buggy Flats and the other in the Buttercup areas. Law enforcement shares facilities 

with the park rangers; there is no specific area reserved only for law enforcement use.

The closest hospital to the North Dunes area is Pioneer Memorial, located in Brawley, 

approximately 35 miles from the ISDRA. The closest hospitals to the South Dunes area are 

Yuma Regional in Yuma, Arizona, located approximately 25 miles from the ISDRA; and El 

Centro Regional Medical Center in El Centro, located approximately 20 miles from the 

ISDRA.
145

3.4 Social

Introduction

This section focuses on the demographics and social trends occurring in parts of Arizona and 

California. The ISDRA draws the majority of its recreational visitors from Southern 

California, including San Diego, Riverside, San Bernardino, Orange, Imperial, and Los 

Angeles Counties, and Arizona, including Yuma, Pima and Maricopa Counties. Since the 

ISDRA is located within Imperial County, California, and with Yuma County, Arizona, to 

the immediate east, additional focus will be given to these two geographical areas. In 

addition, the following individuals and groups will be discussed: OHV recreational users, 

environmental advocacy groups, vendors, OHV related business owners, and local 

communities.

Demographics

In 2000, the nine counties had an estimated population of 22.6 million, up from 19.3 million 

in 1990. This represents an increase of over 3.3 million people (17 percent) in a decade. 

Table 3.4-1 provides a summary of the current population in the nine counties as well as 20-

year population projections for each county. All counties except Los Angeles showed 

double-digit increases in population between 1990 and 2000. Imperial County’s 30.2 percent 

increase was second only to Riverside County’s 32.0 percent increase among the six 

California counties. Two of the Arizona counties, Maricopa and Yuma, experienced growth 

rates of 44.8% and 49.7%, respectively.

The 20-year projections suggest continued growth for the nine counties. Triple digit growth 

is projected for Riverside, Maricopa and Imperial counties. In addition to the projected 

growth within Imperial County, increased population in the other counties of the study area 

will move population centers closer to Imperial County.
146

 Table 3.4-1: Population Estimates for the Nine Counties in the 

 Affected Environment, 1990 – 2020.

1990 2000 2010 2020 % 

Increase 

1990-

2000

% Increase 2000 -

2020

Imperial 109,303 142,361 217,500 294,200 30% 169%

 Los Angeles 8,863,164 9,519,338 10,605,200 11,584,800 7.4% 31%

 Orange 2,410,556 2,846,289 3,266,700 3,541,700 18% 47%

 Riverside 1,170,413 1,545,387 2,159,700 2,817,600 32% 141%

 San Bernardino 1,418,380 1,709,434 2,231,600 2,800,900 20% 97%

 San Diego 2,498,016 2,813,833 3,288,400 3,863,500 13% 55%

 Maricopa 2,122,101 3,072,149 3,709,566 4,516,090 45% 113%

 Pima 666,880 843,746 1,031,623 1,206,244 26% 81%

 Yuma 106,895 160,026 171,689 209,861 50% 80%

Study Area Total 19,365,708 22,652,563 26,781,978 34,834,895 17% 80%

Imperial County occupies an area of 4,587 square miles in the southeastern corner of 

California. It is bounded on the north by Riverside County, on the west by San Diego 

County, on the south by Mexico, and on the east by the Colorado River and Yuma County, 

Arizona. The ISDRA is located within a sparsely populated, unincorporated area of Imperial 

County. The 2000 census indicated that Imperial County had a total population of 142,361 

(California DOF-1, 2001). There are seven incorporated cities in the county, the three largest 

being El Centro, Calexico, and Brawley with populations of 37,835; 27,109; and 22,052, 

respectively. Seventy-seven percent of the County’s inhabitants live in the incorporated 

areas. Table 3.4-2 shows the county and city populations for Imperial County in 1990 and 

2000.
147

Table 3.4-2 Imperial County/City Population Estimates

County/City 1990 

1990 

Percentage of 

Total 2000

2000 

Percentage of 

Total

Brawley 18,923 17 22,052 15

Calexico 16,633 17 27,109 19

Calipatria 2,690 3 7,289 5

El Centro 31,405 29 37,835 27

Holtville 4,820 4 5,612 4

Imperial 4,113 4 7,560 5

Westmorland 1,380 1 2,131 1

Unincorporated 27,339 25 32,773 23

Incorporated 81,964 75 109,588 77

County Total 109,303 100 142,361 100

Source: California DOF-1, 2001

Based on the 2000 census data, approximately 72 percent of the population of Imperial 

County was classified as Hispanic. Whites were the next largest ethnic group at 20 percent of 

the population. The remaining 8 percent of the county population was classified as African 

American, Asian and Pacific Islander, American Indian, or Other (including those identifying 

two or more racial backgrounds). These percentages are comparable to the 1990 data as 

shown in Table 3.4-3.

Table 3.4-3 Imperial County Racial Profile

Race 1990 

1990 

Percentage of 

Total 2000

1997 

Percentage of 

Total

White 31,901 29 28,768 20.2

Hispanic 71,935 66 102,817 72.2

African 

American

2,272 2.1 5,148 3.6

Asian and 

Pacific 

Islander

1,632 1.5 2,521 1.8

American 

Indian

1,563 1.4 1,736 1.2

Othera1,371 1.0

Total 109,30

3

100 142,361 100

Source: California DOF-2, 2001; 2000 U.S. Census 

aThe 2000 estimate for Others includes those identifying two or 

more racial backgrounds. Two or more racial background 

identification was not part of the 1990 Census.
148

Yuma County occupies an area of 5,522 square miles in the extreme southwest corner of 

Arizona. It is bordered by the Colorado River and Imperial County, California, on the west 

and Mexico on the south. The 2000 census indicated that Yuma County had a total 

population of 160,026 (Census, 2000). There are seven incorporated cities in the county, the 

three largest being Yuma, Fortuna Foothills CDP, and San Luis with populations of 77,515; 

20,478; and 15,322, respectively. Sixty-four percent of the inhabitants of the county live in 

the incorporated areas. In Yuma County, the City of Yuma is the population center nearest to 

the ISDRA. Table 3.4-4 shows the county and city population for Yuma County. 

Table 3.4-4 Yuma County/City Population Estimates

County/City 1990

1990 Percentage 

of Total 2000

2000 Percentage 

of Total

Fortuna Foothills CDP 7,737 7.2 20,478 12.8

Gadsden CDP NA NA 953 0.6

San Luis City 4,212 3.9 15,322 9.6

Somerton City 5,282 4.9 7,266 4.5

Tacna CDP NA NA 555 0.3

Wellton town 1,066 1.0 1,829 1.1

Yuma City 54,923 51.4 77,515 48.4

Unincorporated 41,412 38.7 58,094 36.3

Incorporated 65,483 61.3 101,932 63.7

County Total 106,895 100 160,026 100

Source: Arizona DES-1 and DES-2, 2001

NA = Not available

Hispanics comprise the largest racial group accounting for 50.5 percent of the 2000 

population of the county. Whites are the second largest racial classification comprising 44.3 

percent of the population, while the remaining racial classification of African American, 

Asian and Pacific Islander, and American Indian comprise approximately 2.0, 0.9, and 1.1 

percent of the population, respectively. Table 3.4-5 summarizes the racial profile of Yuma 

County with a comparison to 1990 data. As the data indicate, the number of Hispanics has

increased from about 40 percent of the population of the county in 1990 to about 51 percent 

in 2000. This increase in the percentage of Hispanics has been accompanied by a decrease in 

the White population from 54.4 percent in 1990 to 44.3 percent in 2000.
149

Table 3.4-5 Yuma County Racial Profile

Race 1990 

1990 

Percentage of 

Total 2000

1997 

Percentage of 

Total

White 58,151 54.4 70,956 44.3

Hispanic 43,388 40.6 80,772 50.5

African American 2,776 2.6 3,136 2.0

Asian & Pacific 

Islander

1,188 1.1 1,494 0.9

American Indian 1,178 1.1 1,819 1.1

Other 214 0.2 1,849 0.2

Total 106,895 100 160,026 100

Source: Arizona DES-3, 2001 and Arizona DES-4, 2001

Social Trends

The management of public lands is a part of a controversial discussion on recreational use, 

land use, environmental issues and resource management that is occurring both in the United 

States and globally. Social values for lands and natural resources vary greatly by individual 

and groups. Based on comments received during the public comment period, these values for 

the ISDRA include public use, spiritual use, ecological use, resource protection, resource 

conservation, wilderness, health, and recreation. 

According to Outdoor Recreation In America 1999: The Family and the Environment, 

Americans are concerned about the environment, but they do not think that answer to 

environmental protection is forbidding the use of public lands. 78% of Americans say 

outdoor recreation, overall, has a “good effect” or “no effect” on the environment. 62% 

believe its effects are “good”. 11% say outdoor recreation has a “bad effect”. 

Outdoor Recreation In America 1999: The Family and the Environment also states that many 

Americans believe that the key to environmentally safe recreation is responsible behavior. 

47% of Americans “strongly agree” with the statement: ”if people would just follow the rules 

in parks and other outdoor recreation areas, their use of the land would have no significant 

effects on the environment”, and 42% “mostly agree”. Similarly, 90% “strongly” or “mostly 

agree” that “most recreation is compatible with environmental protection when done 

responsibly”. However, 76% say they are “very concerned that people who engage in 

outdoor recreation hurt the environment by leaving trash and damaging the landscape”. 

The survey data in Outdoor Recreation In America 1999: The Family and the Environment

indicates that most Americans believe that outdoor recreation can promote environmental 

responsibility. 89% “strongly” or “mostly agree” with the statement: “Outdoor recreation 

benefits the environment because it gives people more of a reason to care about 

environmental protection”. 86% agree with the statement “spending time outdoors gives 

people the incentive to take care of the environment properly.”
150

Affected Users

The groupings used in the section are made to facilitate the discussion of social values and 

impacts. Any member of any of these groups may have actual attitudes and values that are 

significantly different than those expressed below. Some members of the public identify 

themselves with one or more of these groups. 

OHV Recreational Users

In California there are 3.5 million OHV recreation enthusiasts: this is 14.2% of all 

households according to CA State Parks, Taking the High Road. Arizona Game and Fish 

Department’s Off-Highway Vehicle Safety and Habitat Protection Program states that OHV 

recreation use on public lands has increased significantly: “Since 1977 the increased use of 

OHVs has out-paced Arizona’s population growth. OHV use has more than doubled, while 

the population has increased by slightly more than 65 percent. A study completed in 1990 

estimated the number of OHV’s (4X4’s, Buggies/Sandrails, ATV’s, Motorcycles, and 

Snowmobiles) in Arizona, to be over 550,000.”

An analysis of the Imperial Sand Dunes Visitor Research Case Study (August 1993) 

characterizes visitors to the ISDRA as predominately white (68%), relatively young (85% 

were 45 years of age or younger), majority male (66%), and most had at least a high school 

education (91%). Most visitors were from California (82%), although many visitors were 

from Arizona (15%). The activity most visitors stated they participated in was OHV riding 

(90%). However, only one third listed OHV riding as the primary reason for visiting the 

dunes. Other reasons included: the dunes, friends, open spaces, play, accessible, curiosity, to 

get away, vacation, and to race. The majority of visitors (94%) learned about ISDRA from 

friends and family. 

 “Many families use outdoor recreation as a way to form bonds and transfer important family 

values to children. A number of Americans feel recreation strengthens the family as a unit 

and the children as individuals” (Outdoor Recreation In America 1999: The Family and the 

Environment). Participation in outdoor activities can greatly increase family interaction and 

foster cohesion. Numerous recreational users identified building family values and family 

interaction as important reasons that they enjoy the ISDRA during the public comment 

period. Several individuals stated at the public comment meetings that participation in 

recreational opportunities at ISDRA gave their teenage children positive social interactions. 

Some members of the public attributed their children’s lack of interest in drugs to their 

increased interest in recreational use of the dunes. Numerous public comments stated that 

the ISDRA has been used by their extended families for several generations. 

Americans believe that today’s young people should participate in recreation. A survey by 

Outdoor Recreation In America 1999: The Family and the Environment showed that 72% of 

the participants believed that outdoor recreation promotes good health, 70% that outdoor 

recreation creates shared experiences family and friends can bond over, 69% that outdoor 

recreation teaches appreciation of nature, 68% that it helps children develop important 

physical skills, 65% that outdoor recreation builds self esteem and personal growth and 62% 

that it helps children develop important interpersonal skills.
151

Many recreational users have concerns about the future of OHV recreational use of the public 

land in the California desert. The number of acres of public lands in the California desert 

that are open to OHV use has decreased since the First Wilderness Act of 1964 designated 

approximately 1 million acres of CA as wilderness. In addition, in 1968-1978, there were 14 

additional areas that were designated as wilderness. Furthermore, Wilderness Acts or 

monument designations in 1984, 1992, 1994, and 1999 increased closed or restricted areas by 

more than 8,581,259 acres.

As summarized in CA State Parks, Taking the High Road: ”The California Desert Protection 

Act of 1994 affected OHV recreation through its wilderness designations and through the 

transfer of BLM land to the National Park Service. The California Desert District Office of 

the BLM managed 13.5 million acres, the majority of which was available for OHV 

recreation prior to passage of the California Desert Protection Act. Of the original 13.5 

million acres, 6.4 million acres (48 percent) were closed”... to OHV use... ” as a result of 

wilderness area designations and land transfers to the National Park Service.” 

The number of participants in OHV activities, as a whole, and at ISDRA and elsewhere has 

increased in the past few decades, while the amount of public land on which to participate 

has decreased. According to CA State Parks, Taking the High Road, “Since 1980, the 

acreage available to Green Sticker vehicles for recreation has shrunk 48 percent in our 

deserts alone, while off-highway vehicle registrations have increased 108 percent.” This 

situation has increased the recreational user’s concern that OHV use of public lands may not 

be available for future generations. There has been a 30% increase in the number of dirt bike 

registrations between 1983 and 2000, a 96% increase in the number of All-Terrain Vehicle 

registrations between 1983 and 2000, a 96% increase in the number of dune buggy and sand 

rail registrations between 1983 and 2000 and a 74% increase in the number of street licensed 

4 wheel drive vehicle registrations between 1994 and 2000.

Based on comments received during the public comment period, many ISDRA OHV 

recreational users believe that they do not harm environmental resources by their recreational 

activities at the dunes. Many recreational users stated that they have a respect for the land 

and the species that live there. Many commentors stated that survey information on a 

specific endangered species indicated that recreational use was compatible with species 

conservation. Many recreational users stated a belief that concern about species conservation 

was a method being used by environmental groups to close the dunes to recreational use. 

Recreational users have become more informed about the environmental concerns at the 

ISDRA during the past decade. Recreational users are funding and supporting environmental 

surveys so that they can learn more about the concerns and form their own opinions on the 

issues. 

During the scoping period and the public comment period a group of non-traditional 

recreational users had been identified. This group visits the dunes to recreate in a manner 

that is unsafe and troublesome. They participate in illegal and unsafe activities. This group 

of recreational users will not be discussed further in the social section of this document, as 

their use of the ISDRA is considered as unacceptable. Their behaviors and future will be 
152

discussed further in the section on Law Enforcement. The mainstream OHV recreational 

users do not identify with this group and do not desire to be associated with their activities.

Environmental Advocacy Groups

Based on the comments received during the public comment period, the environmental 

advocacy groups recreationally use the ISDRA as a hiking area. They desire a quiet, 

peaceful time of reflection and observation of nature during their visit to the ISDRA. Some 

members of this group have indicated that the noise from OHV use is distracting. They 

believe that the solitude and peace they seek is harder and harder to find and that they need to 

establish areas to have this experience. 

According to Outdoor Recreation In America 1999: The Family and the Environment” 51% 

of the environmental leaders and activists say to experience nature is a very important reason 

to participate in outdoor recreation. This percent was the same for environmental spenders 

(those who are willing to pay to improve the environment, but with little time to get involved 

themselves). 

Generally, environmental advocacy groups support a more restrictive plan for the OHV use 

of the ISDRA. Commentors during the public comment process stated that they were 

concerned that the management of the ISDRA would not provide enough acreage for the

protection of threatened and/or endangered species, and other species. They also expressed 

concerns about air quality, pollution, habitat destruction, and disturbance to native plant 

species and wildlife. Many commentors thought that dividing the acreage evenly for 

recreational use and protection would be desirable. Many environmental advocacy group 

comments indicated that they were not confident that OHV recreational use could occur 

without harming the environmental resources. 

The conditions and resources on public lands are important to the environmental advocacy 

groups. Many members of these groups appreciate just knowing that these areas exist, even 

if they never visit the areas. Members of these groups feel strongly that the public lands must 

be managed to protect the resources for future generations. Overall, the environmental 

advocacy groups that participated in the public comment process are concerned that OHV 

use is not compatible with their desired recreational experiences, resource conservation and 

resource protection. 

Vendors

The vendors believe that they perform a public service in providing supplies and services to 

the recreational users of the ISDRA. The vendors have stated that their businesses are highly 

profitable, even when operated during the slower periods of the recreational season. They 

believe that they have a right to continue to operate at the ISDRA. Many of the vendors 

believe that they have the right to live where they vend or that they must live near where they 

vend to protect their business from theft. Many of these vendors do not seem to understand 

the special recreation permits regulations under which they are allowed to operate. 

According to comments received from local businesses during the public comment period, 

many vendors do not appreciate the affect they have on local businesses. Many local 
153

businesses believe that they may fail financially if unrestricted vending is allowed to 

continue. Many local businesses believe that they are unable to compete with the vendors 

since the vendors do not have the expenses associated with property ownership.

Based on comments at the public comment meetings, the vendors are concerned with the 

proposed rules and changes to bring the vending program into compliance with BLM’s 

requirements and the federal regulations (43 CFR 8372). The vendors believe that their 

services should be available daily, not just at peak use times. The vendors support 

unrestricted vending and residential use of the vending area. 

OHV Related Business Owners

During the public comment period, many highly profitable OHV related business owners 

described their business and how the proposals in the draft document could impact their 

business. Most business owners felt that any restriction on OHV use could impact their 

business in a negative manner. Some specific law enforcement proposals such as nightly 

curfews were identified as potentially impacting some businesses to the point of nonexistence, for example a business that is involved with exterior lighting of OHVs. However, 

the public comments reflected that reducing the number of recreational opportunities by 

visitor supply controls would most likely have the largest negative financial impact to the 

OHV related businesses. The OHV related business owners support increased use of ISDRA 

for OHV recreation and indicated that jobs would be lost of OHV use was severely restricted.

Local Communities

During the public comment period, numerous officials from the local communities stated that 

they support the use of the ISDRA for OHV recreation. They stated that the recreational use 

of the ISDRA provides jobs for their communities at grocery stores, restaurants, gas stations, 

medical facilities, and vehicle sales, repair and supply shops. Some officials indicated that 

the money that is spent in their communities then is redistributed in the community through 

the local residents spending their salaries. The affect of the money spend by the recreational 

users is expected to be significant due to the cumulative affect of the jobs that are supported 

by these expenditures. 

Local community businesses also participated in the public comment period. These 

businesses supported the recreational use of the dunes and indicated that jobs would be lost if 

the ISDRA significantly restricted OHV use. 

The increased law enforcement at the ISDRA includes the use of local law enforcement 

officers. Currently, the cost associated with the use of local law enforcement officers is paid 

for with a grant. The local community support of providing law enforcement officers for the 

ISDRA may change if continued external funding is not available to support their efforts. 

The local communities expressed a concern related to the use of local land, including 

privately owned land, by OHV recreational users. There is a concern that if the use of 

ISDRA is restricted, more recreational users who are turned away for the ISDRA may 

trespass into the privately owned desert land in the local communities to camp and ride 

without permission. This conflict is becoming more apparent as users from urban areas 
154

travel to more rural areas to recreate. As stated in CA State Parks, Taking the High Road:

“At one time, local OHV opportunities were accessible to Southern Californians, even within 

such heavily urbanized counties as Orange, Los Angeles, and San Diego. As regional 

populations increased within these areas and the usable OHV land was decreased, outlying 

rural areas began to receive heavier use and “backyard” riding resulted in increased user 

conflicts and complaints in the urban/rural interface. Today, the situation is exacerbated by 

an increased and legitimate interest in protecting natural resources within rural riding areas 

and increasing user conflicts in once rural OHV areas that are now rapidly being absorbed 

into the urban edge.” 
155

3.5 Economic

Introduction

To evaluate the economic conditions that may be affected by the management of the ISDRA, 

this section will present trends in regional employment, income, and finance. Economic 

data are generally reported at the County level, so this section will describe the economic 

conditions at the county level for both Imperial and Yuma. In addition, selected, available 

OHV specific economic information will be presented.

Imperial County, California

The civilian labor force in Imperial County in 2000 was about 58,500. The average 

unemployment rate in the civilian labor force was 26.3 percent, compared to 4.9 percent for 

the State (California EDD, 2001). Historically, Imperial County has had one of the highest 

unemployment rates within the state, approaching 30 percent during the 1990s. The primary 

employment sectors in the county are the government, agriculture, trade, and service. The 

table below shows the major employment sectors for 2000. The agriculture and government 

sectors are the dominant sectors in the county providing approximately one in two jobs. The 

bulk of the other jobs are in the trade (both wholesale and retail) and services sectors. Retail 

trade employs 8,300 people and accounts for 16.7 percent of the industry employment. 

Services employ 5,700 and account for 11.4 percent of the industry employment. According 

to comments received during the public comment period, the retail trade and service 

employment of Imperial County is directly linked to sales to recreational users of the ISDRA. 

Loss of jobs could occur if visitation to the ISDRA is severely limited.

The per capita income for Imperial County in 1999 was $17,550, one of the lowest in 

California and well below the state average of $29,856 (California DOF-4, 2001). Median 

family income for 1990 was estimated at $25,147. The percent of person below the poverty 

level in 1990 was 23.8 percent compared to 12.5 percent for the state (California DOF-5, 

2001).
156

 Summary of Imperial County Employment Data, 2000

Employment Numbers Percentage of Total

Agriculture 11,300 22.7

Construction and Mining 2,100 4.2

Manufacturing 1,900 3.8

Transportation and Public 

Utilities

1,900 3.8

Wholesale Trade 2,100 4.2

Retail Trade 8,300 16.7

Finance, Insurance and Real 

Estate

1,100 2.2

Services 5,700 11.4

Government: 15,500 31.1

Federal Government 1,800 3.6

State and Local 

Government

13,700 27.5

Total Industry Employment 49,800a100.0

Source: California EDD, 2001.

aDifference in totals is due to the differences in labor force and employmentby-industry data. 

Taxable retail sales in Imperial County was $871.2 million in 1999 (California DOF-6, 

2001). This represents about 0.3 percent of total state retail sales. The sales tax rate in the 

county is 7.5 percent. 

Yuma County, Arizona

The average civilian labor force in Yuma County in 2000 was about 65,700. The average 

unemployment rate in the civilian labor force was 27.5 percent compared to 3.9 percent for 

the state (Arizona DES-5, 2001). The primary employment sectors in the county are the 

government, trade, and services. The table below shows the major employment sectors for 

2000.
157

 Summary of Yuma County Employment Data, 2000

Employment 

Numbers Percentage of Total

Agriculture 7,475 15.7

Construction and Mining 2,750 5.8

Manufacturing 2,200 4.6

Transportation and Public Utilities 1,550 3.3

Trade 11,250 23.6

Finance, Insurance and Real Estate 1,325 2.8

Services 9,625 20.2

Government: 11,425 24.0

Federal Government 2,075 4.4

State and Local Government 9,350 19.6

Total Industry Employment 47,600a100.0

Source: Arizona DES-5, 2001.

aDifference in totals is due to the differences in labor force and employment-byindustry data. 

The government, trade, and services sectors are the dominant sectors in the county providing 

one out of every three jobs. The government sectors (federal, state, and local) employ 

11,425 people (about 24 percent), whereas the trade sectors employ 11,250 people (about 24

percent). The services sector employs 20.2 percent (or 9,625) of the labor force. According 

to comments received during the public comment period, the retail trade and service 

employment of Yuma County is directly linked to sales to recreational users of the ISDRA. 

Loss of jobs could occur if visitation to the ISDRA is severely limited.

The per capita income for Yuma County in 1999 was $18,452 ranking 10th out of the 15 

counties in Arizona. The average per capita income for the state was approximately $25,173. 

Median family income for 1990 was estimated at $23,635 (Arizona DES-6, 2001). In 1990, 

the poverty rate stood at 19.9 percent, a figure that is more than the state average of 15.7 

percent (Arizona DES-7, 2001). 

Taxable retail sales in Yuma County was $780 million in 1999. (Smith, 2002). This 

represents about 2 percent of total state retail sales. The sales tax rate in the county in 1999 

was 7.10 percent (Heugly, 2002).

OHV Economics 

A Survey by Sacramento State University, Institute for Social Research, 1993 assessed the 

economic impact OHV recreation has on the California. This survey determined that 43,000 

jobs within California are affected by OHV recreation. According to the survey, OHV 

recreation generates about $1.6 billion in personal income. Comments received during the 

public comment period support these findings: numerous business owners, both in California 

and Arizona, testified that their business is directly related to and affected by OHV use. 
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They indicated that their business could be directly affected financially by severe restrictions 

on visitor use of the ISDRA. 

The table below provides a summary of the affects of OHV recreation on the state of 

California’s economy. Over two billion dollars are directly related to OHV purchases, fuel, 

parts, repairs, accessories, equipment and insurance.

OHV Recreation Economics for California

 Item or Service Expenditures

 OHV purchases $1,166,000,000

 Fuel, parts, repair, and insurance $646,000,000

 Accessory and equipment $491,000,000

 Groceries, restaurants, lodging $469,000,000

 Misc. costs and other equipment $244,000,000

 Total $3,049,000,000

Data from CA State Parks, Taking the High Road

“More than four million people visit lands designated for off-highway recreational use each 

year, and this ever more popular form of recreation contributes more than $3 billion to the 

state economy each year” according to CA State Parks, Taking the High Road.
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3.6 Land Use and Land Ownership

Regional Setting

The ISDRA is located in southeastern California, in Imperial County, a county that extends 

over 4,597 square miles, bordering on Mexico to the south, Riverside County to the north, 

San Diego County on the west, and the State of Arizona on the east. Although lying in the 

desert east of the Peninsular Range of Southern California, the availability of irrigation water 

from the Colorado River has made possible a substantial agricultural economy in Imperial 

County. Approximately one-fifth of the land in the county is irrigated for agricultural 

purposes, while about half of county lands are largely undeveloped and under federal 

ownership. There are seven incorporated cities within Imperial County: Brawley, Calexico, 

Calipatria, El Centro, Holtville, Imperial, and Westmorland. These incorporated cities, as 

well as the unincorporated communities and supporting facilities, occupy less than 1percent 

of the land in the county.

The Imperial Sand Dunes, also referred to as the Algodones Dunes, extend from central 

Imperial County more than 40 miles into the southeastern portion of the county. The dunes 

and associated sand sheets generally form the eastern boundary of the agricultural area of 

Imperial Valley. The dunes themselves form a band averaging 5 miles in width. The ISDRA 

itself is roughly bordered on the west by the Coachella Canal, which delivers Colorado River 

water to the fertile agricultural valley to the north and west. A major east-west route of the 

Union Pacific Railroad skirts the eastern edge.

The dune system, extending from northwest to southeast, is crossed by two major east-west 

highways, near which recreational use traditionally has been concentrated. To the north, SR78 crosses at the small settlement of Glamis, and connects Brawley (29 miles west of 

Glamis) with Blythe (60 miles northeast of Glamis). At the south end of the recreational 

area, I-8 crosses the dunes in the Buttercup Valley area. This highway provides access from 

El Centro and Southern California to the west, and from Yuma and the urban centers of 

Arizona to the east. 

The ISDRA Plan Area includes not only the most of the sand dunes system, but also adjacent 

sand sheets to the west, and dissected distal alluvial fans to the east. Land use patterns 

(excluding recreational use) are less constrained than they are in the sand dunes themselves. 

These adjacent lands include the area east of Glamis along Ted Kipf Road and the Union 

Pacific Railroad to the east, and the East Mesa Area including the land between the Old 

Coachella Canal and the New Coachella Canal.

For management and reference purposes, the ISDRA has been generally divided into three 

areas. The northern-most area is known as Mammoth Wash. South of Mammoth Wash is 

the North Algodones Dunes Wilderness, which was established by the 1994 California 

Desert Protection Act. This area is closed to mechanized use and is accessible only by hiking 

and horseback. The largest and most heavily used area for OHV recreational purposes is 

south of the wilderness, beginning at SR-78 and continuing south beyond I-8 to the border 

with Mexico. 
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Regulatory Framework

Plans and policies applicable to the management and ownership of any parcel or right-of-way 

depend upon the agency responsible for managing the lands involved. Primarily, the lands 

within the ISDRA are public lands managed by the BLM. The governing laws and 

applicable land management plans for these lands are the:

Federal Land Policy and Management Act of 1976 (P.L. 94-579, as amended)

California Desert Protection Act of 1994 (P.L. 103-433)

BLM California Desert Conservation Area Plan of 1980, as amended

Lands under private ownership exist within and adjacent to the Plan Area boundary. 

Applicable land management plans and policies for these lands include the Imperial County 

General Plan and the Imperial County Zoning Regulations. 

Two parcels of land owned by the California State Lands Commission (CSLC) lie within the 

ISDRA Plan Area. California State Lands Commission does not actively manage these 

parcels.

Federal Land Policy and Management Act of 1976, As Amended

In 1976, Congress enacted the FLPMA and established the 25-million-acre CDCA. FLPMA 

was enacted to direct the management of the public lands of the United States, including the 

12 million acres of public lands within the CDCA. Section 601 of FLPMA required BLM to 

develop a plan to “...provide for the immediate and future protection and administration of 

the public lands in the California Desert within the framework of a program of multiple use 

and sustained yield, and the maintenance of environmental quality.” The CDCA Plan, 

discussed in more detail below, was created to establish guidance for the management of the 

public lands of the California Desert by the BLM, including the ISDRA.

Congress, in Section 102(a)(7) of the Federal Land Policy and Management Act of 1976, 

declared that the public lands included in the Act were to be managed “on the basis of 

multiple use.” FLPMA defines multiple use as “... the management of the public lands and 

their various resource values so that they are utilized in the combination that will best meet 

the present and future needs of the American people; making the most judicious use of the 

land for some or all of these resources or related services over areas large enough to provide 

sufficient latitude for periodic adjustments in use to conform to changing needs and 

condition...” The definition goes on to allow some areas to be managed for “...less than all 

the resources; a combination or balanced and diverse resource uses that takes into account the 

long-term needs of future generations for renewable and nonrenewable resources...” (Section 

103(c)). 

The Federal Land Policy and Management Act of 1976 states in Title VI – Designated 

Management Areas, Section 601, “The Congress finds that –

(1) The California desert contains historical, scenic, archeological, environmental, 

biological, cultural, scientific, educational, recreational, and economic 

resources that are uniquely located adjacent to an area of large population, 
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(2) the California desert environment is a total ecosystem that is extremely fragile, 

easily scared, and slowly healed, 

(3) the California desert environment and its resources, including certain rare and 

endangered species of wildlife, plants and fishes, and numerous archeological 

and historic sites, are seriously threatened by air pollution, inadequate Federal 

management authority, and pressures of increased use, particularly 

recreational use, which are certain to intensify because of the rapidly growing 

population of southern California; 

(4) the use of all California desert resources can and should be provided for in a 

multiple use and sustained yield management plan to conserve these resources 

for future generations, and to provide present and future use and enjoyment, 

particularly outdoor recreation uses, including the use, where appropriate, of 

off-road recreational vehicles... ”

California Desert Protection Act of 1994

The CDPA established 69 wilderness areas located on BLM-managed public lands. In its 

findings for the CDPA, Congress declared that (1) wilderness is a distinguishing 

characteristic of the public lands in the California desert, (2) the wilderness values of desert 

lands are increasingly threatened by activities and intrusions associated with incompatible 

use and development, and (3) the preservation of desert wilderness requires the highest forms 

of protective designation and management. The CDPA established the North Algodones 

Dunes Wilderness, located in the northern portion of the ISDRA Plan Area, beginning just 

north of SR-78, and ending just at the proposed Mammoth Wash Management Area (see 

Figure 1-2). This enhanced the multiple-use aspect of the ISDRA by assuring primitive, nonmotorized recreational experiences would be available along with motorized recreational 

activities in other parts of the ISDRA. 

California Desert Conservation Area Plan

The CDCA Plan is a comprehensive, long-range plan for the use and management of the 

12 million acres of public land within the boundaries of the California Desert Conservation 

Area. The CDCA Plan was adopted in 1980, and subsequently has been amended on a 

periodic basis. The goal of the CDCA Plan is to provide and enhance uses for public lands 

without diminishing the environmental, cultural, and aesthetic values of these lands (BLM, 

1980).

The ISDRA is located entirely within the CDCA. The majority of the public lands within the 

CDCA have been designated under a multiple-use classification system. The CDCA 

Multiple-Use Classes are discussed in Chapter 2 and illustrated in Figure 3.6-1.

All four MUCs are represented within the ISDRA. The North Algodones Dunes Wilderness 

is located within lands designated Class C. The CDCA Plan assigned much of the central 

dunes and Pilot Knob Mesa on the eastern edge of the dunes to Class L, to protect sensitive 

plant and wildlife habitat. East Mesa south of SR-78, the area east of Glamis, and South 

Ogilby Dunes were placed in Class M. Class I areas within the ISDRA include the 

intensively used OHV activity areas such as those near Glamis, along the Gecko Road, and 
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Buttercup Valley. The management objective of these areas is to enhance opportunities for 

OHV recreation.

In addition to MUCs, the CDCA also designated ACECs, areas where special management 

attention is required to protect and prevent damage to important natural and cultural 

resources. Within the ISDRA, is the Plank Road ACEC and immediately adjacent to the 

southwest boundary is the East Mesa ACEC. The former was designated an ACEC to protect 

this historic resource, and the latter was designated to ACEC to protect habitat of the flattailed horned lizard.

Imperial County General Plan and Zoning Regulations

As Imperial County has no direct land use jurisdiction over public lands, neither the General 

Plan nor the Imperial County zoning regulations are directly applicable to activities proposed 

on public lands. However, private lands scattered throughout and adjacent to the Plan Area 

are under the jurisdiction of Imperial County.

The state-mandated Imperial County General Plan (General Plan) was developed to create a 

balanced, comprehensive guide for future physical growth of lands within the county, and to 

provide mechanisms to achieve the desired goals and objectives of the county. The General 

Plan strives towards achieving a balance between development and economic, social, and 

environmental resources. The General Plan consists of nine elements: Land Use, Housing, 

Circulation and Scenic Highways, Noise, Seismic and Public Safety, Agriculture, 

Conservation and Open Space, Geothermal and Transmission Resources, and Water 

Resources (Imperial County, 1993).

A land use map that depicts existing and projected land use development patterns within 

Imperial County is provided as part of the Land Use Element of the General Plan (Land Use 

Plan). The Land Use Plan indicates that the ISDRA and vicinity, including both public- and 

privately-owned lands, are located within a larger area currently zoned “S-2, Open Space 

Preservation,” with the exception of some small, scattered parcels of land zoned S-1 (Open 

Space Recreation) or C1-PE (Neighborhood Commercial, Pre-existing). The Conservation 

and Open Space Element of the Plan is concerned with open space and other environmental 

resources. The purpose of the Conservation and Open Space Element of the General Plan is 

to:

Promote the protection, maintenance, and natural resources of the county with 

particular emphasis on scarce resources and resources that require special control and 

management

Prevent the wasteful exploitation, destruction, and neglect of the natural resources of 

the state

Recognize that natural resources must be maintained for their ecological value as well 

as for the direct benefit to the public
163

View Figure 3.6-1

Multiple use classes - 62 Kb 
164

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165

Protect open space for the preservation of natural resources, the managed production 

of resources, outdoor recreation, and public health and safety

The General Plan provides for the preparation and adoption of specific plans as “planning 

tools” to implement the general plan for further studies as needed prior to development. Two 

specific plan areas are in the immediate vicinity of the ISDRA. The boundaries of the 8,960-

acre Felicity Specific Plan Area approach the ISDRA from the west. It is intended that this 

plan area will be developed with a full range of residential, commercial, and light industrial 

uses in a manner compatible with the natural setting of the site and its visibility from I-8. 

The Felicity Specific Plan is currently in litigation and has not been approved (Imperial 

County, 2001a). The Glamis Specific Plan Area is approximately 160 acres and is located 

just inside the eastern boundary of the ISDRA at SR-78. The Glamis Specific Plan Area is 

intended to accommodate recreation-supporting land uses including retail and service 

commercial, motel accommodations, recreational vehicle and mobilehome parks, and 

community facilities. Except as needed for onsite employees, the Glamis Specific Plan does 

not include use areas for permanent occupancy

Land Ownership and Rights -of-Way

A mixed ownership pattern, with public land managed by the BLM comprising most of the 

land, exists within the ISDRA planning area (Figure 3.6-2). 
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167

View Figure 3.6-2

Land Ownership and Management - 89Kb 
168

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169

In addition to a limited number of parcels in private ownership as well as lands withdrawn 

for other federal use (such as that by the Department of Defense or the Bureau of 

Reclamation) under FLPMA the BLM has granted a number of rights-of-way for facilities 

within the ISDRA (Table 3.6-1).

Table 3.6-1 Rights-of-Way And Other Entitlements Within The ISDRA Planning Area

Mammoth Wash Management Area

1. Cathodic Protection Unit Site R/W (LA 0158160)

2. BLM Windmill and Wildlife Water Tank Sites (2) R/W (CA-8714)

North Algodones Dunes Wilderness Management Area

1. BLM Windmill and Wildlife Water Tank Site R/W (CA-8714)

2. State Route 78 R/W (CA-14630)

3. Military Target Area (R 05657)

Gecko Management Area

1. Military Target Area (R 05657)

2. Old Coachella Canal R/W (LA 056654)

3. Withdrawal Yuma Reclamation Project - New (Realigned) Coachella Canal

4. BLM (Gecko Road) Easement (CA-2551)

5. Glamis Known Geothermal Resource Area (CA-17575)

6. Fiber Optic Line (AT&T) R/W (CA-41690)

7. Underground Telephone Line R/W (CA-19125)

8. Temporary Use Permits for Apiary Sites along Coachella Canal

Glamis Management Area

1. Underground Telephone Line R/W (CA-19125)

2. Road R/W (CA-40791)

3. State Route 78 (Realigned portion) R/W (CA-17922)

4. Fiber Optic Line (AT&T) R/W (CA-41690)

Adaptive Management Area

1. Military Target Area (R 05657) 

2. Cathodic Protection Unit Site R/W (LA 0158161)

3. Glamis Known Geothermal Resource Area (CA-17572)
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Table 3.6-1 Rights-of-Way And Other Entitlements Within The ISDRA Planning Area

Dune Buggy Flats Management Area

1. All American Canal R/W (LA 077775)

2. Proposed Withdrawal, All American Canal Lining Project (CA-34475)

3. Old Coachella Canal R/W (LA 056654)

4. Withdrawal Yuma Reclamation Project - New (Realigned) Coachella Canal 

5. Military Target Area (R 05657)

6. Temporary Use Permits for Apiary Sites along Coachella Canal

Ogilby Management Area

1. Interstate 8 Highway R/W (LA 0165008)

2. State Highway (Grays Well Overpass) R/W (CA-17911)

3. Transmission Line R/W (LA 055613)

4. Transmission Line R/W (CA-5865)

5. County Road (Ogilby) R/W (CA-19171)

6. Communication Site, Access Road and Transmission Line R/W (CA-17182)

7. Railroad R/W (east boundary of management area)

8. All American Canal and Well Sites R/W (LA 077775)

9. Proposed Withdrawal, All American Canal Lining Project (CA-34475)

Buttercup Management Area

1. Utility Corridor J (2 miles wide)

2. All American Canal and Associated Telephone and Transmission Line R/W (LA 077775)

3. Transmission Line R/W (CA-5865)

4. Transmission Line R/W (CA-18904)

5. Transmission Line R/W (LA 055165)

6. Transmission Line R/W (LA 0164553)

7. Powerline Extension (to All American Canal) R/W (CA-35934)

8. Underground Telephone Line R/W (CA-26357)

9. Underground Fiber Optic Line (Level 3) R/W (CA-41192)

10. Barrier (U.S. Border Patrol) R/W Reservation (CA-34052)

11. Road (Grays Well Road) R/W Reservation to BLM (CA-19131)

12. Interstate 8 Highway R/W (LA 0165008)

13. State Highway (Grays Well Overpass) R/W (CA-17911)

14. Interstate 8 Highway and Ancillary Facilities R/W (R 07237)

15. Interstate 8 Highway and Ancillary Facilities R/W (R 01737)

16. Proposed Withdrawal, All American Canal Lining Project (CA-34475)
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Table 3.6-1 Rights-of-Way And Other Entitlements Within The ISDRA Planning Area

Planning Area

1. Strip of Land Acquired by and Under Jurisdiction of BOR (CA-19902)

2. Old Coachella Canal R/W (LA 056654)

3. Underground Fiber Optic Line (AT&T) R/W (CA-41690)

4. Cathodic Protection Unit Site R/W (LA 0158162)

5. State Route 78 (Realigned Portion) R/W (CA-17922)

6. Railroad Spur R/W (CA-29617)

7. Mineral Material Site (LA 0164722)

8. Cathodic Protection Unit Site R/W (R-374)

9. Easement to U.S. for Gordons Well Road (CA-37234)

10. Barrier (U.S. Border Patrol) R/W Reservation (CA-34052)

11. County Road (Old Hwy. 80) R/W (R 01737)

12. Underground Telephone Line R/W (CA-26357)

13. Road R/W (LA 0165008)

14. All American Canal, Telephone Line R/W (LA 077775)

15. Transmission Line R/W (LA 055165)

16. Transmission Line R/W (LA 164553)

17. County Road (Old Hwy. 80) R/W (R 01737)

18. Road, Pipeline, Wells, Transmission Line (CA-21618)

19. Mineral Material Site (LA 0133909)

20. RS 2477 County Road (Vista Mine Road and Zappone Road) R/W (CA-19169)

21. State Highway (Portion of Hwy. 78) R/W (CA-14630)

22. Underground Telephone Line R/W (CA-19125)

23. Road R/W (CA-8503)

24. Road R/W (CA-40791)

25. All American Canal R/W (LA 077775)

26. Seismographic Monitoring Site R/W (CA-2953-22)

27. Transmission Line R/W (CA-5865)

28. Underground Fiber Optic Line (Level 3) R/W (CA-41192)

29. State Highway R/W (R 137)

30. Surveillance Camera and Access Road (U.S. Border Patrol) R/W Reservation 

(CA-40000)

31. Telephone Line and Road R/W (CA-18904)

32. Temporary Use Permits for Apiary Sites along Coachella Canal 

R/W – Right-of-way

As with other BLM-administered lands, rights-of-way and temporary use permits within the 

ISDRA are normally granted subject to other valid, pre-existing rights including the right of 

entry unless specifically prohibited. Rights-of-way, temporary use permits, and other similar 

entitlements are normally not granted if the use for which the right of way is intended would 

conflict with a valid pre-existing use. Thus, OHV recreational activities still occur on utility 

rights-of-way within the ISDRA. Entry into lands that have been withdrawn or reserved, on 

the other hand, is normally precluded for purposes other than those intended for the 
172

withdrawal or reservation. Hence, public entry is prohibited in the military areas noted 

above.

While most Bureau of Reclamation (BOR)-withdrawn lands have been relinquished within 

the ISDRA, some of the lands around the U.S. Navy East Mesa Target Area and between the 

Old and New Coachella Canals remain withdrawn. Under terms of a 1978 agreement, BLM 

has recreation management responsibility for these lands but must obtain BOR concurrence 

on all management actions. In addition, BOR retains a withdrawal on the rights-of-way of 

the new Coachella Canal and All-American Canal (1,000 feet on either side of the canal 

centerline). BOR must approve BLM management programs initiated within the canal 

rights-of-way. BOR programs are the paramount use on all BOR-withdrawn lands.

Existing Land Uses

Existing land uses within the ISDRA planning area are primarily recreational, although 

agricultural, transportation, communication, military, and other uses also occur. Multiple-use 

classes, as defined in the CDCA Plan (see above), are used to guide land use in the ISDRA; 

those uses are discussed below. The CDCA Plan also identifies certain areas within the 

ISDRA as open, limited, or closed to OHV use. Detailed discussions of existing recreational 

uses in the ISDRA, including OHV uses and camping, are provided in Section 3.1 

(Recreational Resources).

Recreational Use And Mu ltiple-Use Classes Within the ISDRA

Lands located within the ISDRA planning area have been assigned to an MUC that defines 

permitted uses on those lands. Land uses currently occurring within each MUC are described 

below and are primarily recreation based. Areas with restricted vehicle use or areas that are 

open or closed to OHV uses are discussed as they occur within each MUC.

Class C

Lands identified as Class C make up the 26,202-acre North Algodones Dunes 

Wilderness, as created by Congress through the California Desert Protection Act of 

1994. Solitude and primitive recreation are the primary land uses within the 

wilderness. Primitive camping is allowed, but developed camping sites or facilities 

are not available. No commercial uses are permitted, and the use of motorized 

vehicles of any kind is prohibited. Most use in the wilderness takes the form of short 

photographic and sightseeing walks from SR-78, although hiking, backpacking, and 

nature study trips also occur. The wilderness is closed to OHV use (see Figure 3.6-3).

Class L

Lands identified as Class L (Limited Use) make up most of the southern half of the 

ISDRA, including much of the central dunes and Pilot Knob Mesa. Limited Use 

lands are intended to protect sensitive natural, scenic, ecological, and cultural 
173

View Figure 3.6-3

OHV Designations - 104Kb 
174

blank
175

resource values. This class is suitable for recreation that generally involves low to 

moderate user densities. Developed campgrounds or sites involving concentrated 

recreational use are generally not allowed in this class. Most of the central dunes 

Class L area is lightly used, with use consisting primarily of OHV day use with little 

camping. However, the Ogilby Camp Area is located in Class L lands in the 

southeastern portion of the ISDRA. 

Class M

Class M (Moderate Use) lands are located along the eastern and southern boundaries 

of the ISDRA and west of Glamis along SR-78. These lands are intended to provide 

for a balance between higher intensity use and protection of public lands. 

Recreational use is appropriate at moderate to high densities, and developed 

recreation sites are permitted. The Class M lands east of Glamis are temporarily 

closed to camping in accordance with the settlement agreement. OHV use on Class 

M lands is limited to approved routes of travel.

Class I

Class I (Intensive Use) lands provide for the concentrated use of lands and resources 

to meet human needs. Recreation activities involving high densities are permitted. 

Areas of the dunes assigned to Class I include the intensively used OHV areas around 

Glamis, Buttercup Valley, and Mammoth Wash. The management objective of these 

areas is to enhance opportunities for OHV recreation. Campgrounds and other 

facilities are permitted. 

High-density camping and OHV uses occur in Class I. Many established 

campgrounds are located along SR-78, Gecko Road, and I-8. Primarily those 

participating in OHV activities on Class I lands use these campgrounds. The Class I 

lands immediately south of SR-78 are the most intensively used. Also intensively 

used is the Buttercup Valley Class I area, which is located just north and south of I-8. 

The Class I area near Mammoth Wash at the north end of the ISDRA receives only 

light-to-moderate use, owing largely to difficulty in accessing it.

Non-Recreational Land Uses

Some BLM-managed land within the ISDRA planning area has not been assigned an MUC. 

These lands are located along the east side of the ISDRA and parallel the Union Pacific 

Railroad, as well as additional lands east and north of Glamis. Generally, they were 

recognized in the CDCA Plan to be lands that may be put to some use other than recreation in 

the future. The land paralleling the Union Pacific Railroad is designated by the CDCA Plan 

as a contingency utility corridor, while the land in the vicinity of Glamis may accommodate 

activities and uses associated with the settlement of Glamis.
176

In addition to the extensive recreation-based uses that take place within the ISDRA, a wide 

variety of non-recreational uses take place within or immediately adjacent to the ISDRA.

Agricultural Uses

BOR-withdrawn lands within the ISDRA planning area include those between the Old 

Coachella Canal the New Coachella Canals. In addition, BOR has maintenance and 

management responsibility for the New Coachella Canal and the All-American Canal. In 

addition to the canals, which are critical to supporting the agricultural industry of the 

Imperial Valley, a number of temporary use permits have been granted for apiaries. 

Military

Current Department of Defense activities within the ISDRA planning area focus on over 

flights to and from the military training areas to the east of the ISDRA, and use of lands in 

the vicinity of several target areas (Figure 3.6-2). The U.S. Navy and BLM have developed a 

Cooperative Agreement for management of public lands in range safety zones surrounding 

Navy Targets 68 and 95 on East Mesa. A Desert Plan amendment necessary to implement 

the agreement was proposed in 1985. The amendment would close East Mesa lands between 

Target 68 and the old Coachella Canal to OHV use. Under terms of the Cooperative 

Agreement, the Navy will review all proposed management actions within Range Safety 

Zone C, which includes the Gecko Management Area and much of the North Algodones 

Dunes Wilderness, to ensure conformity with structural height restrictions and other 

guidelines to safeguard aircraft operations near the targets.

Mining and Quarrying

Mineral materials removal within the ISDRA planning area is restricted to sand and gravel 

quarrying, and is found to the east of the dunes in the Pilot Knob Mesa area. Free-use and 

sales permits have been issued. These uses and resources are discussed in greater detail 

Section 3.14, Geology, Energy, and Mineral Resources.

Energy Production

The northern half of the ISDRA planning area is closed to all geothermal leasing. The dunes 

south of the Glamis/Gecko Open Area are open to leasing subject to a no surface occupancy 

stipulation. All areas outside the dunes proper are open to leasing with appropriate 

mitigation. Although such activities take place elsewhere in the vicinity of the ISDRA, no 

geothermal leases have been issued; and no development has taken place within the ISDRA. 

No development of oil or gas resources has occurred within the ISDRA. These resources are 

discussed in Section 3.14, Geology, Energy, and Mineral Resources. 

Utilities and Transportation

Two major road rights-of-way (SR-78 and I-8) cross the recreation area in an east-west 

direction, while the Union Pacific Railroad runs northwest to southeast in the eastern ISDRA. 

The two roads provide the chief access to the ISDRA. A major utility corridor within the 

recreation area passes through the Buttercup Valley Open Area parallel to I-8. Existing 

facilities include a 500 kilovolt (kV) transmission line and a number of smaller power and 

telephone lines. Transmission lines also parallel the Coachella Canal and the Union Pacific 
177

Railroad. A high-pressure gas pipeline is located within the railroad right-of-way, and a 

microwave relay tower is located west of Ogilby.

Commercial and Residential Uses

Commercial land uses within the ISDRA planning area are restricted to those at the Glamis, 

and the activities of vendors in locations and at times authorized by the BLM. There are also 

two businesses located in the Planning Area. Most of these vending operations are restricted 

to high-use periods, chiefly the holidays and during the October through May season, when 

the population of OHV enthusiasts in the ISDRA swells. No permanent, residential land use 

occurs on BLM managed lands within the ISDRA, other than at the Cahuilla Ranger Station 

complex. That occurring on private lands is restricted to the residence for the storeowners at 

Glamis.
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3.7 Visual Resources

Introduction

Visual resources are managed by controlling how the landscape is altered from the natural 

appearance, and by introducing or maintaining variety into the “seen” area. Visual variety 

contributes to high-quality recreation experiences. Visual variety at the ISDRA is evidenced 

by contrasts in the ever-changing sand dunes and vegetation. Most of the landscape appears 

natural (undisturbed) with very few human-made landscape alterations. Many opportunities 

exist for undisturbed views that have little human intervention. The composition of the dune 

formations, fine textures, and color contrast between the darker vegetation and light sand is 

what gives the ISDRA its distinctive landscape character.

Provided below is a discussion of the regulatory framework of the BLM and a description of 

the visual resources of the ISDRA. 

Regulatory Framework

The BLM has developed a system (the Visual Resource Management [VRM] Program) for 

evaluating the visual resources of a given area to determine what degree of protection, 

rehabilitation, or enhancement is desirable and possible. The BLM is concerned with 

managing visual resources equally with other resources and attaining acceptable levels of 

visual impact without unduly reducing commodity production or limiting overall program 

effectiveness.

The purpose of the VRM Program’s is twofold: (1) to manage the quality of the visual 

environment and (2) to reduce the visual impact of development activities, while maintaining 

effectiveness in its resource programs. Managing the visual aspects of changes to the natural 

landscape is particularly important for the BLM because most activities taking place on BLM 

lands involve some degree of alteration.

Perception of visual quality in a landscape is based on several common principles:

Landscape character is determined by four basic visual elements (form, line, color, and 

texture), which are present in every landscape and exert varying degrees of influence. 

The stronger the influence exerted by these elements, the more interesting the landscape.

Landscapes with more visual variety are more aesthetically pleasing. Variety in the landscape 

with harmony is considered attractive; landscape alterations that create disharmony are 

considered unattractive (BLM, 1980).

The BLM has not formally inventoried the lands within the ISDRA, nor has it given those 

lands relative visual ratings (Management Classifications), according to the VRM Program. 

However, these ratings will be developed based on the multiple use class later in this chapter. 

There are five Visual Resource Management Classes (VRM Classes) to describe the different 

degrees of modification allowed to the basic elements of the landscape. These are briefly 

described below:
179

Class 1: Natural ecological changes and very limited management activity area

allowed. Any contrast created within the characteristic landscape must not attract 

attention. This classification is applied to wilderness areas, wild and scenic rivers, and 

other similar situations.

Class 2: Changes in any of the basic elements (form, line, color, texture) caused by a 

management activity should not be evident in the characteristic landscape. Contrasts 

are seen, but must not attract attention.

Class 3: Contrasts to the basic elements caused by a management activity are evident, 

but should remain subordinate to the existing landscape.

Class 4: Any contrast attracts attention and is a dominant feature of the landscape in 

terms of scale; but it should repeat the form, line, color, and texture of the 

characteristic landscape.

Class 5: The classification is applied to areas where the natural character of the 

landscape has been disturbed to a point where rehabilitation is needed to bring it up to 

one of the four other classifications. The classification also applies to areas where 

there is potential to increase visual quality of the landscape. It would be applied, for 

example, to areas where unacceptable cultural modification has lowered scenic 

quality; it is often used as an interim classification until objectives of another class 

can be reached.

The BLM currently manages the lands within the ISDRA according to the Multiple-Use 

Classes listed in the California Desert Conservation Area Plan. The CDCA Multiple-Use 

Classes are discussed in Chapter 2 and illustrated in Figure 3.7-1.

The VRM Classes that are associated with these Multiple-Use Classes are listed in 

the following table.

VRM Classes Associated with the Multiple-Use Classes Assigned to 

the Imperial Sand Dunes Recreation Area

Assigned Multiple-Use 

Classa Associated VRM Class

Class I Intensive Use VRM Class 4

Class M Moderate Use VRM Class 3

Class L Limited Use VRM Class 2

Class C Controlled Use VRM Class 1

VRM Class 5 was not assigned to any of the Multiple-Use Classes because none of the lands 

in the ISDRA have been degraded to the point where they require rehabilitation. 

Figure 3.7-1 depicts the VRM Classes associated with the Multiple-Use Classes that are 

assigned to ISDRA lands by management areas. Although the management areas do not 

exactly fall within the multiple use class, geographically, the following table will provide a 
180

general overall classification of the management areas as a whole. (However, a visual 

assessment conducted without regard to the multiple use class may result in different 

classifications, such as Mammoth Wash Management Area would most likely be VMR class 

2.) As shown in Figure 3.7-1, the popular dune areas and campgrounds within the ISDRA 

also can be categorized according VRM Classes. 

Visual Resource Management Classes of OHV Use and Camping Areas

VRM Class 1 VRM Class 2 VRM Class 3 VRM Class 4

North Algodones 

Dunes Wilderness

Dune Buggy 

Flat 

Management 

Area

Glamis 

Management 

Area

Mammoth 

Wash 

Management 

Area

Adaptive 

Management 

Area

Buttercup 

Management 

Area

Ogilby 

Management 

Area

Gecko 

Management 

Area

Existing Visual Resources

The following description of the visual resources of the landscape at various areas within the 

ISDRA is based on a site visit conducted on October 16 and17, 2001. The climatic 

conditions during the site visit included cloudy skies, no wind, and temperatures estimated to 

be in the 90s degrees Fahrenheit. The ISDRA is a mostly undeveloped area consisting of 

sand dunes ranging in elevation from approximately 100 to 640 feet, depending on location 

within the dunes. The differing shapes of the dune forms add interest to the landscape. The 

homogeneous sand color and the fine sand texture provide a strong contrast to the blue sky 

and add visual interest to the view. Certain dunes, such as Competition Hill, have horizontal 

ridges across the dune hills. These ridges are known as “whoop-de-do’s.” They add texture 

to the visual landscape, as do the vehicle tire tracks on the dunes. 

The dunes present a spectacular landscape. From the interior of the dunes, views in all 

directions are of dunes that are smooth, rounded hills of fine-textured, light-colored sand. 

Most of the dunes are devoid of vegetation. The unvegetated dunes do not provide much 

variety in view, but present an interesting one that is enhanced by the stark contrast of the 

dunes against the blue, clouded sky. The dunes that have low-lying shrub vegetation 

scattered across them also provide visual interest due to the contrast in texture and color 

provided by the vegetation and the color contrast provided by the sky. The dunes are of 

varying sizes, heights, and shapes due to winds blowing the sand and OHV use patterns. The 

closed areas and the wilderness area appear pristine, with no vehicle tracks visible. Most of 

the ISDRA lacks human-made development.
181

View Figure 3.7-1

Visual Resource Management Areas by MUC - 82Kb 
182

Blank page back
183

Development within the ISDRA includes the Cahuilla Ranger Station, the vendor areas, the 

Glamis Beach Store, and the development at certain campgrounds. Other human-made 

development is concentrated at or near the boundaries of the ISDRA recreational 

management area boundary. This includes the Union Pacific Railroad tracks and pipeline 

aboveground markers that exist along the eastern boundary of the recreation management

area, the overhead electric distribution line, and the New Coachella Canal that exists along 

the western edge. SR-78 is the major easterly trending two-lane road that crosses the ISDRA 

at the southern edge of the North Algodones Dunes Wilderness. I-8 also is an easterly 

trending roadway near the southern edge of the ISDRA, and the All American Canal parallels 

I-8 on its north side. High-voltage electric transmission line development also occurs in the 

southern area and a communications tower exists near the Ogilby Camp Area. This 

development near the ISDRA boundaries reflects the character of a more urban developed 

area.

The ISDRA is open year-round; however, due to high summer temperatures, use tends to 

occur from October through Easter of each year.In addition, use on weekdays is minimal, 

and use on most weekends is moderate. The peak season is concentrated into six holidays: 

Halloween, Thanksgiving weekend, New Years, Martin Luther King Day, President’s Day, 

and Easter break (which lasts a few weeks due to the differing “spring breaks” offered by 

various schools).

Although OHV use occurs throughout the open areas of the ISDRA, certain areas receive 

higher levels of use, such as Osborne Lookout, Competition Hill, Oldsmobile Hill, Brawley 

Slide Hill, Patton Valley, Test Hill, and Plank Road. During the mid-week site visit, only a 

few recreationists were present at these locations. Views of these areas revealed large open 

expanses of land (sand dunes and the flat open, sandy areas). The areas appeared relatively 

pristine, lacking both much human-made development and signs of heavy recreation use. 

Vehicle tire tracks and boundary posts were the only signs of use/development across the 

dunes. The high use that occurs at these areas at peak times reflects the BLM’s VRM Class4 

management of these areas.

Mammoth Wash, at the northern end of the ISDRA, receives minor use due to its remoteness. 

This area has dunes that are smaller than the areas further south, so less OHV opportunity 

exists there. This northern area has private land interspersed with BLM land. Grapefruit 

orchards abut the dunes, which adds color, texture, line, and form variety to the dune 

landscape.

OHV users intent on camping concentrate use at the Gecko Campground, Keyhole 

Campground, Roadrunner Campground, The Washes, Ogilby Camp Area, Buttercup 

Campground, and Midway Campground. During the site visit, these camp areas appeared to 

be vacant, vast expanses of level sand, some of which had restroom buildings and trash 

dumpsters, but no other development visible. These areas also appeared relatively pristine, 

except for the restroom and trash facilities and the signage that exists at certain areas. 

Photographs of these areas during peak-use weekends show these areas overflowing with 

recreational vehicles, OHVs, camping equipment, and recreationists, which result in a strong 
184

visual contrast to what was seen during the site visit. Review of these photographs provides 

a more accurate picture of the intensive use that occurs within these VRM Class 4 areas. 

The Cahuilla Ranger Station, located just south of SR-78 on Gecko Road, consists of a small 

building and fenced equipment/vehicle storage yard. Also on Gecko Road is a vendor 

concessionaire area. At the time of the site visit, it was mostly vacant. One vendor, who 

stays there year-round, was present. The presence of vendors in this area during the peak use 

times of the year reflects a human-made character that strongly contrasts with the natural, 

undeveloped character of the dunes.

Osborne Lookout is located approximately 3 miles east of the Cahuilla Ranger Station on the 

south side of SR-78. It consists of a gravel parking area where camping is allowed at the 

southern end and day use viewing is allowed at the northern end of the area. Views to the 

east from the lookout are of rolling dunes in the foreground and middle ground, and of the 

Black Mountains in the background. To the north are the North Algodones Dunes 

Wilderness in the foreground and the Chocolate Mountains in the distance. Views to the 

west and south are of the dunes. 

The microphyll woodland area, located to the east of Oldsmobile Hill, is heavily vegetated 

due to flash floods that occur there. The abundance and type of vegetation present in this 

area is not characteristic of much of the ISDRA. This area exhibits much color and texture 

that is not seen in other areas of the ISDRA.

The Wildlife Viewing Area, near the North Algodones Dunes Wilderness, is the only 

interpretive area away from the Cahuilla Ranger Station. The viewing area includes 

explanatory wildlife and habitat information on interpretive boards. Motorized vehicle use is 

not allowed or evident away from the viewing area within the wilderness area.

The Plank Road area provides a historic view of a wood plank road constructed in the early 

1900s to allow motorists to cross the desert. Fragments of the Plank Road remain, and a 

small area of a replica of the Plank Road has also been constructed to show the public how 

the historic road once appeared. Interpretive information is also displayed at the partially 

fenced Plank Road area.

Two different types of Border Patrol barriers exist along I-8 on its south side to the west of 

the Buttercup Campground. The purpose of these barriers is to exclude illegal aliens from 

entering the United States from Mexico. These barriers provide varying levels of 

effectiveness. The barriers are painted white with red accents. Their form, color, and line 

contrast with the undisturbed desert landscape; however, this area is also a utility corridor 

that includes several high-voltage electric towers of varying designs.

To the east of the ISDRA and the Planning Area, is the Mesquite Mine (located to the east of 

the Union Pacific Railroad tracks). The mine includes the Mesquite Mine Overlook Trail, a 

3-mile-long gravel trail that climbs a hill. It provides benches for resting, interpretive 

displays along the trail, and wheelchair access for the first portion of the trail. Views from the 
185

Mesquite Mine Overlook include the sand dunes, the mining area, and tailings. To the 

southwest, there is an unobstructed view of Oldsmobile Hill from this location. 

Views from Ted Kipf Road traveling southeast from The Washes toward Ogilby Road 

include visible mining scars in the Cargo Muchacho Mountains to the east.
186

3.8 Water Resources

Introduction

The Imperial Sand Dunes Recreation Area is located in the desert southeastern California, an 

area marked by long, hot summers and meager rainfall. Surface water in the extended 

vicinity of the ISDRA includes the Salton Sea, the Colorado River, and the Gulf of 

California. Other than canals that carry Colorado River water to the Imperial 

Valley, water resources in the immediate vicinity of the ISDRA are quite limited.

Surface Waters

There are two primary surface waterways in the vicinity of the ISDRA, the All American 

Canal and the New Coachella Canal.

All American Canal

All-American Canal is approximately 80 miles long and is part of the federal irrigation 

system of the Hoover Dam. The canal was built between 1934 and 1940 across the Colorado 

Desert and is entirely within the United States. Water is diverted from the Colorado River 

into the canal at the Imperial Dam. Flow proceeds in a westerly direction, and smaller 

distributary canals carry water from it into the Imperial Valley and Coachella Valley. This 

canal system irrigates more than 600,000 acres in the Imperial and Coachella agricultural 

region, and has greatly increased crop yield in the area.

The All American Canal has a bottom width of approximately 160 feet and depth of about 

21 feet. The canal is lined with clay to minimize seepage. The capacity of the canal is 

10,155 cubic feet per second (cfs) in the vicinity of the ISDRA. Although the All American 

Canal is lined, a substantial amount of water is believed to be lost through seepage.

Coachella Canal

The New Coachella Canal is connected to the All American Canal at what is known as 

Drop 1 in the southern ISDRA near I-8 (see Figure 1-2). The Coachella Canal originally was 

completed in 1949 as an unlined channel and had a flow capacity of approximately 2,500 cfs. 

The canal extends northwesterly from Drop 1 (All American Canal) for approximately 

123 miles and runs along the east side of the Salton Sea and west of the Plan Area. The first 

48 miles of the Old Coachella Canal were replaced with a new canal called the New 

Coachella Canal in the early 1980s due to concerns about water loss through seepage in the 

East Mesa area. The Old Coachella Canal is no longer used to transport water.

The 48-mile New Coachella Canal has a flow capacity of approximately 1,550 cfs and is 

concrete lined to prevent seepage. Operating roads are located along either side of the newer 

canal. The New Coachella Canal has a bottom width of approximately 16 feet and ranges in 

depth from 10 to 12 feet. It runs northeast near the proposed Dune Buggy and Gecko 

Management Areas, and also provides a feature used to delimit the borders between the 

ISDRA and the Planning Area (see Figure 1-2).
187

Wildlife Guzzl ers

Seepage along the Old Coachella Canal resulted in a greenbelt and pools along the canal that 

supported various forms of wildlife. With construction and operation of the New Coachella 

Canal and the subsequent retirement of the southern portion of the Old Coachella Canal, 

wildlife dependent on the greenbelt and pools no longer had a water source. To partially 

mitigate the loss of this wetland habitat, the California Department of Fish and Game 

installed four windmill wells in the North Algodones Dunes Wilderness Management Area 

and two windmill wells in the Mammoth Wash Management Area to the north. More 

recently, solar panels and electric pumps replaced the windmills. The wildlife guzzlers have 

created limited wetland and green areas within the northern portion of the ISDRA that 

provide vegetation and water for wildlife.

Ephemeral Surface Flows

Numerous washes that carry storm runoff exist within the ISDRA. These are particularly 

evident as generally east to west flowing channels that have incised the distal alluvial fans of 

the Chocolate Mountains and the Cargo Muchacho Mountains in the eastern portion of the 

ISDRA. Ephemeral surface flows and pools form in the washes and low points in the eastern 

transition areas as a result of infrequent runoff events caused by cloudbursts in the nearby 

mountains. The ephemeral surface flows and pools most commonly occur in the springtime 

of wet years, but can also occur at other times. The pools do not remain for long periods 

following rains due to the permeable nature of the soils in this area.

Groundwater

The ISDRA is located within what recently has been termed the Amos-Ogilby-East Mesa 

groundwater basin (RWQCB, 2001). The basin is a northwesterly trending, elongated area of 

approximately 860 square miles within the southeastern portion of Imperial County, 

California, generally following the alignment of the trough of the Gulf of California north to 

the Salton Sink. It is bounded on the east by the Chocolate and Cargo Muchacho Mountains, 

on the north by the surface drainage/groundwater divide that separates the Amos Basin from 

the East Salton Sea Basin, on the west by the fine-grained, less permeable sediments of the 

central Imperial Valley, and to the south by the boundary with Mexico. The alluvial 

sediments that make up the water-bearing aquifer range in thickness from 0 feet on the 

eastern boundary at the Chocolate Mountains to as much as 10,000feet at the western 

boundary of the basin in the Imperial Valley. Depth to groundwater in the ISDRA is 

estimated to be several hundred feet below ground surface.

Beneficial Use Designations

The ISDRA is located in the Colorado River Basin within the jurisdiction of the Regional 

Water Quality Control Board District 7 (RWQCB7). The Colorado River Basin includes all 

of Imperial County and portions of San Bernardino, Riverside, and San Diego Counties. The 

RWQCB7 approved the Basin Plan for the Colorado River Basin in 1993; and this plan 
188

established beneficial use designations for the All American Canal, Coachella Canal, and the 

Amos-Ogilby hydrologic unit. The beneficial uses of these water sources are presented in 

the table below.

 Beneficial Use Categories

Category All American 

Canal

Coachella 

Canal

Amos-Ogilby 

Unit

Municipal and Domestic Supply X P X

Agricultural Supply X X

Aquaculture X

Industrial Service Supply X

Groundwater Recharge X X

Water Contact Recreation X X

Noncontact Recreation X X

Warm Freshwater Habitat X X

Wildlife Habitat X X

Hydropower Generation X

Freshwater Replenishment X

Preservation of Rare, Threatened, or 

Endangered Species

X X

Source: 1993 Basin Plan – Colorado River Basin.
189

3.9 Cultural Resources

Overview

Although an arid area, the ISDRA contains evidence of human activity from prehistoric times 

to the present. The eastern desert of Imperial County has served as a transportation corridor, 

with the Algodones dune fields encouraging most travelers to seek routes to the north or 

south of the Plan Area until the early 20th century. 

Prehistory 

The ISDRA was utilized prehistorically by a variety of Native American groups, including 

the Yuman-speaking Quechan and Kumeyaay (Kamia) and possibly the Takic-speaking 

Cahuilla. The extreme aridity of the dunes suggests that permanent habitation sites probably 

do not exist there; but temporary camps, resource acquisition and processing sites, and travel 

corridors are known to occur, especially around the dune margins.

Well-documented human occupation of the southern California Deserts occurred as early as 

12,000 years ago, but some researchers have posited much earlier occupations as well. The 

Paleoindian period is manifested locally by the San Dieguito Complex, dating from about 

12,000 to about 7,000 years ago. Most evidence suggests that these peoples were highly 

nomadic hunter-gatherers, who ranged widely across the arid Southwest. The subsequent 

Archaic period from about 7,000 to about 1,500 years ago is much better documented in 

surrounding areas, such as the Mojave Desert, the California coast, and Sonoran Desert in 

Arizona, than in the Lower Colorado Desert. Very few Archaic period sites have been found 

in Imperial County, due, in part, to arid conditions and loss due to Colorado River erosion 

and other impacts (Schaefer, 1994). Human occupation increased dramatically after 1,500 

years ago. Archaeologists believe that ancestral Yuman-speaking groups settled along the 

Lower Colorado River during this time when the manufacture of pottery was first introduced. 

Agriculture, including the cultivation of maize, was also introduced, leading to increased 

populations. During this time, hydrological changes in the Colorado River delta caused the 

river to flow north into the Salton basin and form a vast fresh-water lake known as Lake 

Cahuilla. Native American groups from the river to the east and the Peninsular and 

Transverse ranges to the west occupied the shores of the lake at least on a temporary basis. 

During the Late Prehistoric period, long-distance travel for trade, warfare, and religious 

pilgrimages was a common practice. Travel corridors probably traversed the Dunes, 

although major trails also skirted the deep sand.

Yuman-speaking Indians included the area in their tribal territory when Spaniards began to 

exert influence in the region in the late 1770s. Major settlements for these aboriginal groups 

were typically located in the mountains to the west or along the Colorado River to the east. 

Groups would collect resources in the Plan Area and return to larger encampments. 

History

Early Spanish incursions into the Lower Colorado region began in 1540, although Spanish 

influence was relatively minor until the 18th century. Relationships with the local inhabitants 
190

were not always good. Initially most development occurred along the Colorado River. In the 

mid-1880s, to support local mining efforts, the Southern Pacific Railroad built a line that 

crosses what is now the eastern portion of the ISDRA. Regular service on the route began in 

1877. Small communities, such as Ogilby, developed at some of the stops along the line. 

Around the turn of the century, the Imperial Valley experienced considerable population 

growth after the construction of irrigation projects. To the present day, Imperial Valley is an 

important agricultural area. In 1915, the planning and hard work of a group of businessmen, 

including Edward Fletcher and Edwin Boyd, resulted in the construction of the first plank 

road though the dunes (PHR Associates and Carrico, 1989). At one time, there were 8miles 

of the wooden road, providing a route that shortened travel time from SanDiego to Yuma by 

2 days (Bates, 1970). During World War II, undeveloped portions of southeastern 

California, western Arizona, and southern Nevada became a vast military training area. 

Camp Pilot Knob, located west of the ISDRA, was one of the desert military training camps 

established by General George S. Patton, Jr. This large temporary settlement comprised 

3,000 tents occupied by the 55th Infantry Division. In 1943, they used the camp and the 

surrounding areas, including the dunes, for military training maneuvers.

The 1970s and 1980s saw several construction projects in the southern part of the recreation 

area, with the replacement of SR-80 with I-8 and the construction of a 500-kV transmission 

line. These features joined the All American Canal, which had been built in the 1930s.

Current Inventory

A records search was conducted at the South East Archaeological Information Center to 

identify previous studies in the area and to locate known cultural resources. One cultural 

resource site currently featured for visitors to the ISDRA is the Plank Road, portions of 

which can be viewed adjacent to I-8. In 1985, the BLM designated the Plank Road an 

ACEC. The Plank Road, All American Canal, and Coachella Canal all are eligible for the 

National Register of Historic Places (NRHP).

Surveys

At least 20 archaeological studies have been conducted within the limits of the ISDRA. 

Some of the earliest documented work was in the 1950s, with the majority of surveys being

carried out in the 1980s and 1990s. Many of the inventories were associated with linear 

projects (highways, canals, pipelines, and transmission lines). An exception to this was a 

major sample survey effort that the BLM conducted in the late 1970s and early 1980s. In this 

study, a large number of 1-mile by 1⁄4-mile transects were surveyed throughout the dunes 

(Bull, 1981). Despite a number of studies having been conducted, most of the ISDRA has 

not been inventoried for cultural resources (see the table below).

Based on the records search results, the level of survey appears to vary in different parts of 

the ISDRA. The southern portion of the ISDRA has been subject to the most survey 

investigations. These investigations were generally associated with infrastructure projects 

and the BLM sample survey. A stratified random sample survey of 3% of the entire dune 

system and an additional 2% sample of the Quaternary alluvium within the dunes and dune 

edges was undertaken in the spring of 2002. This 5% sample of the dune system yielded four 
191

archeological sites: three pottery shards scatters and a historic military marksmanshiptraining site.

Reported Survey Coverage By ISDRA Management Area

Management Area

Approximate

Survey 

Coverage

Mammoth Wash <1%

North Algodones Dunes Wilderness <2%

Gecko 5%

Glamis <3%

Dune Buggy 16%

Adaptive Management 6%

Ogilby <1%

Buttercup 14%

Planning Area <1%

Cultural Resources

Over 124 cultural resources are recorded in the planning areas, which includes the ISDRA 

and the Planning Area. Of these cultural resource sites, 24 are recorded within the dunes 

system itself. As the table below indicates, most of these are prehistoric archaeological sites, 

representing a range of activities. Although fewer historic period resources have been 

identified, these reflect the major historic themes of the region: mining, transportation, 

irrigation projects, and military activity.

ISDRA Cultural Resources Summary

Prehistoric Resources Historic Period Resources

Lithic scatters 6 Debris scatter/dump 17

Ceramic scatters 40 Military encampment 3

Habitation 

areas/temporary camps

9 Plank 

road/Roads/Railroad

5

Cleared circle 1 Canal 2

Lithic and ceramic 

scatter

7 Transmission line 1

Cremation 2 Rock features 1

Isolated finds 14 Movie 

set/Townsite/Graveyard

4

Isolated finds/Other 14

Total 79 Total 47
192

As indicated in the table below, most of the known cultural resources have been identified in 

the Planning Area and Ogilby Management Areas although the size if the Management Areas 

varies widely. 

 Known Cultural Resources By ISDRA Management Area

Management Area

Prehistoric 

Resources Historic Resources

Sites Isolates Sites Isolates Total

Mammoth Wash 3 0 1 0 4

North Algodones 

Dunes Wilderness 

Area 

1*

Gecko 4 0 1 0 5

Glamis 1 1 2 2 6

Dune Buggy 13 0 0 0 13

AMA 2 0 3 1 6

Ogilby 11 3 7 1 22

Buttercup 7 3 2 0 12

Planning Area 21 7 13 9 50

Resources in Multiple 

Management Areas

0 0 4 0 4

1One resource reported but not identified.

Seven Native American tribes with heritage associations with the dunes were contacted in the 

Spring of 2002 for the purpose of conducting consultation. In addition, members of these 

tribes were interviewed about present and past connections with the dunes to identify 

traditional cultural properties and assess the dunes as a cultural landscape. The results of the 

interviews indicate that the dunes have some cultural significance for contemporary Native 

Americans, but do not meet the criteria set forth under the National Register of Historic 

Places. All groups interviewed expressed concern about damage to the dunes landscape by 

recreational use.

Management Practices

Actions, including projects involving ground disturbing activities, which have the potential to 

have an effect on cultural resources meeting the criteria eligibility of the National Register of 

Historic Places are subject to review under the National Historic Preservation Act. Review is 

accomplished in accordance with Section 106 of that Act, BLM’s National Programmatic 

Agreement with the Advisory Council on Historic Preservation and the National Conference 

of State Historic Preservation Officers, and the State Protocol Between California BLM and 

the California State Historic Preservation Officer. Specific actions which ocur through 

implementation of this plan and which could have an effect on eligible resources will be 

reviewed following the above cited law and agreements.
193

3.10 Transportation and Traffic

This discussion addresses the existing vehicular traffic at the ISDRA. The scope of the 

analysis is limited to major public roads that provide access to the Plan Areas.

Existing Access

Figure 3.10-1 shows the existing access to the Plan Area that extends for more than 40miles 

long and 5 miles wide near the borders of California, Arizona, and Mexico. I-8 is the only 

freeway providing access through the south side of the Plan Area. It is a four-lane facility 

linking San Diego and Arizona. SR-98 is an arterial branch from I-8 south of El Centro. It 

terminates and joins I-8 approximately 15 miles west of the Plan Area. SR-78 is an east-west 

oriented highway traversing across the central part of San Diego and Imperial Counties. It 

provides access to the northern end of the Plan Area and traverses north to link with I-10. 

Ogilby Road is a county road (S-34) linking SR-78 and I-8 along the eastern edge of the Plan 

Area.

Existing Traffic Volumes

Figure 3.10-2 shows 1999 and 2000 traffic volumes on major access roadways in the vicinity 

of the Plan Area. The heaviest traveled segment of roadway is on I-8 west of Sidewinder 

Road. It has an Average Annual Daily Traffic (AADT or ADT) volume of 13,000 vehicles 

and a peak-hour volume of 1,850 vehicles. The existing Level of Service (LOS) for roadway 

segments in the vicinity of the Plan Area is summarized in the table below.

 Table 3.10-1: 2000 Level of Services

Route Segment

Peak-Hour 

Volume

Level of 

Service

(LOS) Notes

I-8 West of SR-98 1,400 B HCM1-98

I-8 East of SR-98 1,650 B HCM-98

I-8 Buttercup 1,700 B HCM-98

I-8 East of Ogilby Rd 1,750 B HCM-98

I-8 East of Sidewinder 

Rd

1,850 B HCM-98

SR-98 West of I-8 160 A v/c2=0.05, rolling terrain, 

no passing 80%

SR-78 West of Glamis 530 C v/c=0.19, rolling terrain, no 

passing 80%

SR-78 East of Glamis 290 B v/c=0.10, rolling terrain, no 

passing 80%

SR-78 East of Ogilby Rd 450 C v/c=0.16, rolling terrain, no 

passing 80%

1HCM: Highway Capacity Manual, Transportation Research Board, National Research 

Council, Figure 3-4

2v/c: Volume over capacity ratio
194

LOS is a measure of the quality of traffic operations based on selected factors of the type of 

roadway. LOS are designated from A through F. LOS A represents the best operation 

condition with significant freedom of maneuver, while LOS F signifies a severely congested 

situation with extensive delays. LOS C is generally accepted as the threshold for rural 

highways. The evaluation of LOS is based on methods recommended in The Highway 

Capacity Manual (HCM) published by Transportation Research Board of the National 

Research Council.

The table above indicates that all segments of roadways are operating at LOS C and better. 

The I-8 freeway is operating at LOS B in the vicinity of the Plan Area. It is based on the 

55-mile-per-hour (mph) free-flow speed and the HCM density flow rate chart for basic 

freeway segments. The LOS on SR-78 varied from A to C, based on HCM LOS chart for a 

two-lane highway on rolling terrain and the assumption that no passing zones comprise 

80 percent of the routes.

Figure 3.10-3 shows the distribution of recreational traffic related to ISDRA on existing 

roadway network. The distribution factors are derived from the Imperial Sand Dunes Visitor 

Research Case Study prepared in 1993 by the BLM. The table below shows the percentage 

of ISDRA traffic on the major highway segments providing access to the Plan Area. It is 

noted that the annual ISDRA traffic has a more significant share on SR-78 west of the Plan 

Area. It is 17.3 percent of the total annual traffic. The percentages of ISDRA traffic on I-8 

are 5.4 percent west of the Plan Area and 0.7percent east of the Plan Area. The shares on I-8 

are relatively low because it is an interstate freeway carrying a significant amount of regional 

traffic between California and Arizona. Based on the annual traffic share volumes, it is 

observed that the segment of SR-78 west of the Plan Area would be more sensitive to the 

ISDRA RAMP that dictates future traffic projections.

 Table 3.10-2: Annual Shares of ISDRA Traffic1

ISDRA Traffic Total Traffic

Access

%

Distribution

1999/2000 

Annual

ISDRA 

Traffic

2000 

AADT2

2000 Annual

Total Traffic

% of Traffic 

Related to 

ISDRA 

I-8 West 50 247,830 9,500 3,467,500 7.1

I-8 East 8 39,669 12,200 4,453,000 0.9

SR-78 West 32 158,675 1,900 693,500 22.9

SR-78 East 8 39,669 1,650 602,300 6.6

SR-98 West 2 9,917 1,450 529,300 1.9

1Based on annual project generated traffic of 495,860

2Annual Average Daily Traffic (AADT)

Source: California Department of Transportation
195

View Figure 3.10-1

Existing Access - 75Kb 
196

Blank page back
197

View Figure 3-10-2

Existing Traffic Volumes - 99Kb 
198

blank page back
199

View Figure 3.10-3

Distribution of Existing Traffic - 78Kb 
200

Blank page back
201

Seasonal Fluctuation and Peak -Hour Volumes

Historical records of ISDRA attendance indicate that it has a highly concentrated seasonal 

fluctuation typical of rural resort areas. The table below estimates the seasonal concentration 

of ISDRA attendance.

 Table 3-10.3: Peak Attendance as ISDRA (2000-2001)

Peak Period Duration

Percent of 

Annual 

Attendance

Halloween 6 days 7

Thanksgiving 8 days 12

New Year 6 days 8

Martin Luther King’s Birthday 6 days 5

President’s Day 6 days 10

Easter 5 days 8

Non-holiday (October – May) 50

The table above shows that the six peak holiday seasons between mid-October and mid-April 

accounted for 50 percent of the visits. The Thanksgiving week is the most crowded week and 

contributed 12 percent of annual attendance.
202

3.11 Noise

Fundamentals of Noise

Noise is defined as unwanted sound. Airborne sound is a rapid fluctuation of air pressure 

above and below atmospheric pressure. There are several ways to measure noise, depending 

on the source of the noise, the receiver, and the reason for the noise measurement. 

Environmental noise levels are typically stated in terms of decibels on the A-weighted scale 

[dB(A) or dBA]. Noise levels stated in terms of dBA reflect the response of the human ear by 

filtering out some of the noise in the low- and high-frequency ranges that the ear does not 

detect well. The A-weighted scale is used in most community ordinances and standards. 

Human hearing typically encompasses the sound range from just above 0dBA at the quietest 

end to approximately 140 dBA, where pain is produced in most listeners and permanent 

hearing loss would result.

Regulatory Framework

The Noise Element of the Imperial County General Plan provides a program for 

incorporating noise issues into the land use and planning process, with a goal of minimizing 

adverse noise impacts to sensitive noise receptors. The Noise Element establishes goals, 

objectives, and procedures to protect the public from noise intrusion. The Noise Element for 

Imperial County is applicable to lands owned or zoned by the county. However, lands 

regulated by the state or federal government, such as the ISDRA, are pre-empted from local 

land use policy (Imperial County, 1993).

Existing Noise Environment

The ISDRA is in a relatively remote desert region of the southeastern portion of the state. 

The Chocolate Mountains and Cargo Muchacho Mountains are located to the north and east 

of the Plan Area. The town of Brawley is located to the west, and Mexico is located to the 

south. Recreational activities that occur on ISDRA include OHV use, camping, hiking, and 

flora/fauna observation.

In deserts where the natural sound pressure levels are very low, vehicular use on a route 

associated with recreational activities, affect hearing in some vertebrates. Natural deserts do 

not exceed 66 decibels, and no desert animal creates sounds above 56 decibels. Mechanized 

sounds increase the decibels in the desert. A motorcycle ranges from 40 to 100 decibels. 

Within 100 meters, the peak decibels created by a motorcycle exceed those of naturally 

occurring sounds. It has been shown that prolonged noise can adversely affect some lizards 

(e.g., desert iguana, Mohave fringe-toes lizard). Laboratory studies show that dune buggy 

sounds, collected from the Imperial Valley, of moderate intensity and short duration cause

hearing loss in Colorado Desert fringed-toed lizards. However, it is not known whether or 

not vehicle noise at levels and durations anticipated in the desert negatively impact flat-tailed 

horned lizards. Exposure to vehicle sounds reduced hearing detection abilities in desert 

kangaroo rats for three weeks. Hearing reductions lead to the animals’ inability to detect its 
203

predator, the sidewinder, for those three weeks. Effects are more likely where prolonged, 

loud noise occurs. (Brattstrom and Bondello, Scharf) 

Ambient noise level measurements for the Plan Area are not available. However, ambient 

noise levels in the Plan Area and vicinity generally are assumed low and typical of remote 

desert areas (i.e., 35 to 50 dBA), except as may be modified by noise- generating activities in 

the Plan Area and vicinity, including:

Noise from train movements on the Union Pacific (formerly the Southern Pacific) 

Railroad tracks located along the east side of the Plan Area

Noise associated with occasional recreational and support activities, especially both 

concentrated and dispersed OHV uses of the Plan Area and immediate vicinity 

Vehicular traffic noise on major roadways leading to the Plan Area

Intermittent military aircraft maneuvers and military weapons explosions associated 

with the use of the Chocolate Mountain Aerial Gunnery Range (CMAGR) located to 

the northwest of the Plan Area and a gunnery range north of East Mesa 

Occasional military aircraft overflights associated with flight corridors located above 

and adjacent to the Plan Area 

Military helicopter use of the Plan Area as a training ground for the use of night 

vision devices 

Border Patrol helicopter use of the Plan Area as a part of providing medical aid, and 

as a part of apprehending undocumented immigrants and smugglers

Mineral exploration, including drilling by Glamis Imperial under existing BLM 

approvals

Natural sources such as wind, rain, thunder, and wildlife

OHV Noise Levels

OHV activities and vehicular traffic on local roads are the primary noise sources in the Plan 

Area. OHV noise levels are variable, with older vehicles producing higher noise levels than 

newer ones. California Vehicle Code Section 38370 requires that decibel levels (measured at 

50 feet) for Green Sticker vehicles be below: (a) 92 bdA for any such vehicle manufactured 

before January 1, 1973, (b) 88 dbA for any such vehicle manufactured on or after January 1, 

1973, and before January 1, 1975, (c) 86 dbA for any such vehicle manufactured on or after

January 1, 1975, and before January 1, 1986, and (d) 82 dbA for any such vehicle 

manufactured on or after January 1, 1986. According to data from Dirt Wheels Magazine, 

and tests from Oregon Dunes National Recreation Area, even with mufflers, noise levels 

from ATVs are found to be in the range of 81 to 111 dBA per unit at a distance of 20 inches 
204

(Scharf, 1999). A noise level of 111 dBA at 20 inches is estimated to attenuate to a level of 

approximately 85 dBA at a distance of 50 feet.

San Diego County performed a preliminary study of various OHV routes (OHV Route 

Location Study) in 1999 to identify and recommend OHV routes in the county. As part of 

that study, the county performed a preliminary noise analysis. Based on feedback from the 

San Diego Off-Road Coalition and input from the State Off Highway Motor Vehicle 

Recreation division (California State Parks), the county determined that a noise level of 

92 dB was appropriate in their study (San Diego County, 2001). For purposes of this section, 

92 dBA will be the assumed noise level at 50 feet for OHV use within the ISDRA.

The level of OHV activities in or near the Plan Area varies throughout the year, with little, if 

any, OHV use and noise during the summer months. Virtually all OHV usage in ISDRA 

occurs from approximately mid-October to May, with approximately 50 percent of total 

annual OHV usage occurring on the following six weekends: Halloween, Thanksgiving, 

New Years, Martin Luther King Jr., President’s Day, and Easter. During these high-use 

weekends, OHV-related noise levels at the ISDRA can be relatively high within certain areas 

of the Plan Area. The remaining 50 percent of annual OHV usage occurs primarily on other 

weekends throughout the October-May period. Therefore, background OHV noise levels in 

and around the Plan Area range from low (during weekdays) to moderate during moderateuse weekends, and high during the six high-use weekends.

Sensitive Receptors

Sensitive noise receptors are, in general, those areas of human habitation or substantial use 

where the intrusion of noise has the potential to adversely impact the occupancy, use, or 

enjoyment of the environment. These can include residences, schools, hospitals, parks, and 

places of business requiring low levels of noise. Since the Plan Area is situated in a very 

remote area, there are no such typical sensitive human receptors in or anywhere near the Plan 

Area. The Cahuilla Ranger Station is located within the Plan Area, but is considered part of 

the administration of the ISDRA and therefore not a sensitive receptor. Hiking and 

flora/fauna observation activities that occur in the North Algodones Dunes Wilderness area 

may be more enjoyable in a quiet environment. 

The closest area of likely sensitive receptors would be an unincorporated area of Imperial 

County located just west of East Mesa and the East Highline Canal (approximately 7 miles 

west of the Plan Area). The town of Brawley is located farther west, approximately 25miles 

to the west of the Plan Area.
205

3.12 Air Quality

Definition of Resource

Air quality is defined by ambient air concentrations of specific pollutants determined to be of 

concern with respect to the health and welfare of the general public. National air quality 

policies are regulated through the Federal Clean Air Act (CAA) of 1970 and its 1977 and 

1990 Amendments. Pursuant to the CAA, the U.S. Environmental Protection Agency (EPA) 

established national ambient air quality standards (NAAQS) to protect the public health and 

welfare from the effects of air pollution. Current standards are established for six air 

pollutants: carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), 

PM10, and lead (Pb). These pollutants are referred to as “criteria” pollutants because 

numerical health-based criteria have been established for each that define acceptable levels of 

exposure. Areas that violate a federal air quality standard are designated as non-attainment 

areas.

Pollutant emissions typically refer to the amount of pollutants or pollutant precursors 

introduced into the atmosphere by a source or group of sources. Pollutant emissions 

contribute to the ambient air concentrations of criteria pollutants, either by directly affecting 

the pollutant concentrations measured in the ambient air or by interacting in the atmosphere

to form criteria pollutants. Primary pollutants, such as CO, SO2, Pb, and some particulates, 

are emitted directly into the atmosphere from emission sources. Secondary pollutants, such 

as O3, NO2, and some particulates, are formed through atmospheric chemical reactions that 

are influenced by meteorology, ultraviolet light, and other atmospheric processes. In general, 

emissions that are considered “precursors” to secondary pollutants in the atmosphere (such as 

reactive organic gases (ROG) and oxides of nitrogen (NOx), which are considered precursors 

for O3) are the pollutants for which emissions are evaluated to control the level of O3 in the 

ambient air.

The California Air Resources Board (CARB) subsequently established the more stringent 

California Ambient Air Quality Standards (CAAQS). Areas within California in which 

ambient air concentrations of a pollutant are higher than the state or federal or both standards 

are considered to be non-attainment for that pollutant. Table 3.12-1 shows both the federal 

and state ambient air quality standards.

EPA has revised the NAAQS several times since their original implementation and will 

continue to do so as the understanding of the health effects of exposure to pollution is 

improved. New standards for 8-hour O3 and PM2.5 were proposed on September 15, 1997; 

and policies and systems to implement these new standards will be developed in the coming 

years. Compliance with these new standards will be addressed during the next update of the 

applicable regional air quality plan, if sufficient monitoring data are available. In some cases, 

there may be delays of several years to allow data collection to determine baseline levels. 
206

Source: ARB Fact Sheet 39 (11/91); SCAQMD bulletin (8/97) and www.arb.ca.gov

1. California standards, other than ozone, carbon monoxide, sulfur dioxide (1hour), nitrogen dioxide, PM10, are values that are not 

to be equaled or exceeded. The ozone, carbon monoxide, sulfur dioxide (1 hour), nitrogen dioxide, and PM10 standards are not to be 

exceeded.

2. National standards, other than ozone and those based on annual averages or annual geometric means, are not to be exceeded 

more than once a year. The ozone standard is attained when the expected number of days per calendar year with maximum hourly average 

concentrations above standard is equal to or less than one.

3. Concentration expressed first in units in which it was promulgated. Equivalent units given in parentheses are based upon a 

reference temperature of 25?C and a reference pressure of 760 mm of mercury. All measurements of air quality are to be corrected to a 

reference temperature of 25?C and a reference pressure of 760 mm of mercury (1,013.2 millibar). PPM in this table refers to parts per 

million by volume or micromoles of pollutant per mole of gas.

4. National Primary Standards: The levels of air quality necessary, with an adequate margin of safety, to protect the public health. 

Each state must attain the primary standards within a specified number of years after that state’s implementation plan is approved by EPA.

5. National Secondary Standards: The levels of air quality necessary to protect the public welfare from any known or anticipated 

adverse effects of a pollutant. Each state must attain the secondary standards within a “reasonable time” after the implementation plan is 

approved by EPA.

6. New federal 8-hour ozone and fine particulate matter standards were promulgated by EPA on July 18, 1997. The federal 1-hour 

ozone standard continues to apply in areas that violated the standard. Contact EPA for further clarification and current federal policies.

Table 3.12-1 California and National Ambient Air Quality Standards

California Standards1 National Standards2

Pollutant

Averaging

Time Concentration3

Primary3,4 Secondary3,5

Ozone (O3) 1 Hour 0.09 ppm (180 μg/m3) 0.12 ppm (235 

μg/m3)

Same as Primary 

Standard

8 Hour - 0.08 ppm6 -

Carbon Monoxide (CO) 8 Hour 9.0 ppm (10 mg/m3) 9.0 ppm (10 

mg/m3)

-

1 Hour 20 ppm (23 mg/m3) 35 ppm (40 

mg/m3)

-

Nitrogen Dioxide (NO2) Annual Average - 0.053 ppm 

(100 μg/m3)

Same as Primary 

Standard

1 Hour 0.25 ppm (470 μg/m3) - -

Sulfur Dioxide (SO2) Annual Average - 80 μg/m3 (0.03 

ppm)

-

24 Hour 0.04 ppm (105 μg/m3) 365 μg/m3

(0.14 ppm)

-

3 Hour - - 1300 μg/m3 (0.5 

ppm)

1 Hour 0.25 ppm (655 μg/m3

) - -

Suspended Particulate 

Matter (PM10)

Annual Geometric Mean 30 μg/m3- -

24 Hour 50 μg/m3150 μg/m3-

Annual Arithmetic Mean

-

50 μg/m3-

Fine Particulate Matter 

(PM2.5)

6

24 Hour - 65 μg/m3-

Annual Arithmetic Mean - 15 μg/m3-

Sulfates (SO4) 24 Hour 25 μg/m3 No Federal 

Standards

No Federal 

Standards

Lead (Pb) 30 Day Average 1.5 μg/m3- -

Calendar Quarter - 1.5 μg/m3Same as Primary 

Standard

Hydrogen Sulfide (HS) 1 Hour 0.03 ppm (42 μg/m3) No Federal 

Standards

No Federal 

Standards

Vinyl Chloride 

(chloroethene)

24 Hour 0.010 ppm (26 μg/m3) No Federal 

Standards

No Federal 

Standards

Visibility Reducing 

Particles

8 Hour (10 am-6 pm, 

Pacific Standard Time)

Insufficient amount to produce an extinction coefficient of 

0.23 per kilometer– visibility of 10 miles or more (0.07-

30 miles or more for Lake Tahoe) due to particles when the 

relative humidity is less than 70 percent. Method: ARB 

Method V (8/18/89).

No Federal 

Standards

No Federal 

Standards
207

ISDRA is located in Imperial County, which is in the Salton Sea Air Basin (SSAB). The 

climate of Imperial County exhibits climatological characteristics typical of a desert: low 

annual precipitation, very hot summers, mild winters, high evaporation rates, and strong 

inversions. One of the main determinants of climatology is a semi permanent high-pressure 

area (the Pacific High) in the eastern Pacific Ocean. In the summer, this pressure center is 

located well to the north, causing storm tracks to be directed north of California. This highpressure cell maintains clear skies for much of the year. When the Pacific High moves 

southward during the winter, weakened low-pressure storms and the orographic barrier 

brings little rainfall. The combination of subsiding air, protective mountains, and distance 

from the ocean severely limits precipitation. In Imperial County, the precipitation level is 

very low, averaging 2.40 inches annually (NOAA, 2001). A summary of the monthly 

temperatures and precipitation are shown in Table 3.12-2. The mean temperature is 73.1?F, 

and the mean maximum and mean minimum temperatures are 87.7° F and 58.5° F, 

respectively (NOAA, 2001).

The flat terrain of Imperial Valley and the strong temperature differentials created by intense 

solar heating produce moderate winds and deep thermal convention. The Imperial Valley 

region occasionally experiences periods of high winds. Predominant wind directions are 

westerly and west-southwesterly during all four seasons, and average annual daily wind 

speed is 4.1 miles per hour (CARB, 1999).

A common atmospheric condition known as a temperature inversion affects air quality in the 

ISDRA. During an inversion, air temperatures become warmer with increasing height rather 

than cooler. The presence of the Pacific high-pressure cell can cause the air mass aloft to 

sink. As the air descends, compressional heating warms it to a temperature higher than the 

air below. This highly stable atmospheric condition is called a subsidence inversion. The 

boundary between the layers of air acts as a temperature inversion that traps pollutants below 

it. The inversion layer can persist for 1 or more days, causing air stagnation and buildup of 

pollutants. Highest or worst-case ozone levels are often associated with the presence of this 

type of inversion. Subsidence inversions are common from November through June, but 

appear to be relatively absent July through October.
208

Table 3.12-2 Average Monthly Temperatures and Precipitation for

Imperial, CA, 1971-2000

Imperial County Airport

Mean Daily Temperatures

Month Maximum (°F) Minimum (°F)

Mean Monthly 

Precipitation 

(inches)

January 69 42 0.42

February 74 46 0.24

March 78 50 0.22

April 85 55 0.11

May 93 62 0.01

June 102 69 0.00

July 107 78 0.10

August 105 77 0.31

September 101 72 0.26

October 91 61 0.21

November 78 49 0.23

December 70 42 0.29

Absolute extreme 

temperatures 119 23 2.40 (total)

Reference: Imperial County, 2001b.

Health Effects of Criteria Air Pollutants

Air pollutants are recognized to have a variety of health effects on humans. Research by the 

CARB shows that exposure to high concentrations of air pollutants can trigger respiratory 

diseases such as asthma, bronchitis, and other respiratory ailments and cardiovascular 

diseases. A healthy person exposed to high concentrations of air pollutants may be become 

nauseated or dizzy, may develop a headache or cough, or may experience eye irritation or a 

burning sensation or both in the chest. Ozone is a powerful irritant that attacks the 

respiratory system, leading to the damage of lung tissue. Inhaled particulate matter, nitrogen 

dioxide, and sulfur dioxide can directly irritate the respiratory tract, constrict airways, and 

interfere with the mucous lining of the airways. When it is absorbed into the bloodstream, 

carbon monoxide can endanger hemoglobin, the oxygen-carrying protein in blood, by 

reducing the amount of oxygen that reaches the heart, brain, and other body tissues. When 

air pollutant levels are high (a common occurrence in Southern California), children, elderly 

people, and people with respiratory problems are advised to remain indoors. Outdoor 

exercise also is discouraged because strenuous activity may cause shortness of breath and 

chest pains. A brief discussion of the criteria pollutants and their effects on human health 

and the environment is provided in Table 3.12-3. 
209

Table 3.12-3 Criteria Air Pollutants and Their Effects on Human Health and the 

Environment

Physical Characteristics Health Effects Environmental Effects

CO is a colorless and 

odorless and at high levels is 

a poisonous gas. It is a 

component of motor vehicle 

exhaust. Peak CO 

concentrations typically 

occur during the colder 

months of the year and 

nighttime inversion 

conditions.

Exposure to CO reduces 

oxygen delivery to the body’s 

organs and tissues. Elevated 

levels are dangerous to those 

who suffer from cardiovascular 

disease. CO can be poisonous, 

can cause visual impairment, 

reduce work capacity and 

manual dexterity, and inhibit 

learning ability.

None.

Ground-level ozone (the 

primary constituent of smog) 

is not emitted directly into 

the air but is formed by the 

reaction of volatile organic 

hydrocarbons (VOCs) and 

nitrogen oxides (NOx) in the 

presence of heat and sunlight.

Exposure to ambient ozone has 

been linked to increased 

hospital admissions and 

emergency room visits for 

respiratory causes, including 

respiratory infection, asthma, 

significant decreases in lung 

function, chest pain, and 

cough.

Ozone also affects 

vegetation and ecosystems, 

leading to reductions in 

agricultural and 

commercial forest yields, 

reduced growth and 

survivability of tree 

seedlings, and increased 

plant susceptibility to 

disease, pests, and other 

environmental stresses 

(e.g., harsh weather).

NO2 is a reddish brown, 

highly reactive gas. The 

major sources of man-made 

NOx emissions are hightemperature combustion 

processes. Home heaters and 

gas stoves also produce 

substantial amounts of NO2

in indoor settings.

Exposures to NO2 may reduce 

airway and lung function, 

increase respiratory illnesses in 

children, and increase 

susceptibility to respiratory 

infection. Atmospheric 

transformation of NOx can lead 

to the formation of ozone and 

PM, both of which are 

associated with adverse health 

effects.

NO2 is a precursor of acid 

rain and is linked to a wide 

range of environmental 

effects, including changes 

in the composition and 

competition of some 

species of vegetation, 

visibility impairment, 

acidification of freshwater 

bodies, eutrophication of 

estuarine and coastal 

waters, and increases in 

levels of toxins harmful to 

fish and other aquatic life.

SO2 is formed when fuel 

containing sulfur (mainly, 

coal and oil) is burned, and 

during metal smelting and 

other industrial processes. 

The highest concentrations of 

Exposure to SO2 can result in 

temporary breathing 

impairment, reduced lung 

function, wheezing, chest 

tightness, or shortness of 

breath, respiratory illness, 

SO2 is a major precursor of 

acid rain, which is 

associated with the 

acidification of soils, lakes, 

and streams, accelerated 

corrosion of buildings and 
210

SO2 occur in the vicinity of 

large industrial facilities.

alterations in the lungs’ 

defenses, and aggravation of 

existing cardiovascular disease. 

monuments, and reduced 

visibility.

PM consists of a mixture of 

airborne solid particles and 

liquid droplets that originate 

from both man-made and 

natural sources. Fine particles 

(PM2.5) are generally emitted 

from fuel combustion 

sources. Coarse particles 

(PM10) are generally emitted 

from sources that cause 

wind-blown or entrained 

dust. SOx, NOx, and VOC 

also interact with compounds 

in the air to form PM. 

Inhalable PM can accumulate 

in the respiratory system and is 

associated with numerous 

health effects, including the 

aggravation of respiratory 

conditions (asthma), increased 

hospital admissions and 

emergency room visits for 

heart and lung disease, 

increased respiratory 

symptoms, decreased lung 

function, and even premature 

death.

PM is the major cause of 

reduced visibility in many 

parts of the United States. 

Airborne particles also can 

cause damage to paints and 

building materials.

Pb emissions to the 

atmosphere were formerly 

dominated by automotive 

sources. As a result of the

elimination of leaded 

gasoline, metals processing 

facilities are currently the 

primary source of Pb 

emissions. The highest air 

concentrations of Pb are 

found in the vicinity of 

smelters and battery 

manufacturers.

Exposure to Pb occurs mainly 

through inhalation and 

ingestion pathways. It 

accumulates in the blood, 

bones, and soft tissues. Pb can 

adversely affect the kidneys, 

liver, nervous system, and 

other organs. Excessive 

exposure to Pb may cause 

neurological impairments, such 

as seizures, mental retardation, 

behavioral disorders, damage 

to the nervous systems of 

fetuses and young children, and 

may be a factor in high blood 

pressure and subsequent heart 

disease.

Lead can also be deposited 

on the leaves of plants, 

presenting a hazard to 

grazing animals.
211

Toxic Air Contaminants

The federal and state laws and regulations also define a group of pollutants called “hazardous 

air pollutants,” “toxic air contaminants,” or “air toxics.” These pollutants are regulated by 

the National Emissions Standards for Hazardous Air Pollutants (NESHAPS) section of the 

federal Clean Air Act; various state laws and regulations; state air toxics acts (e.g., the 

AB 1807, AB 2588, and SB 1731 programs); and Imperial County Air Pollution Control 

District (APCD) Regulations XI and XII. In urban areas, toxic air contaminants are a 

concern because of the concentration of people living close to large sources of emissions. 

The combination of toxic emissions from vehicles, industry, and multiple area sources 

creates an unhealthy mix that varies based on geography, industry, population, and other 

factors. Exposure to toxic air pollutants may cause or contribute to cancer, birth defects, 

genetic damage, and other adverse health effects. 

In Imperial County, the Imperial County APCD is the agency responsible for protecting 

public health and welfare through the administration of federal and state air quality laws, 

regulations, and policies. Included in the tasks for Imperial County APCD are the monitoring 

of air pollution, the preparation of the State Implementation Plan (SIP) for Imperial County, 

and the promulgation of Rules and Regulations. The SIP included strategies and tactics to be 

used to attain the federal O3 standard in Imperial County. The elements are taken from the 

Air Quality Attainment Plan, the APCD plan for attaining the state O3 standard, which is 

more stringent than the federal standard (Imperial County APCD, 1991). The Rules and 

Regulations include procedures and requirements to control the emission of pollutants and to 

prevent adverse impacts.

Federal Clean Air Act Conformity

The CAA Amendments of 1977 (42 United States Code [USC] 7401, et seq.) state that the 

federal government is prohibited from engaging in, supporting, providing financial assistance 

for, licensing, permitting, or approving any activity that does not conform to an applicable 

SIP. Federal actions related to transportation plans, programs, and projects developed, 

funded, or approved under 23 USC or the Federal Transit Act (49 USC 1601, etseq.) are 

covered under separate regulations for Transportation Conformity.

In the 1990 CAA Amendments, EPA included provisions requiring federal agencies to 

ensure that actions undertaken in non-attainment or attainment-maintenance areas are 

consistent with applicable SIPs. Imperial County APCD has adopted Rule 925, General 

Conformity. The process of determining whether or not a federal action is consistent with 

applicable SIPs is called “conformity.” The general conformity rules establish a process to 

demonstrate that federal actions would be consistent with applicable SIPs and would not 

cause or contribute to new violations of the NAAQS, increase the frequency or severity of 

existing violations of the NAAQS, or delay the timely attainment of the NAAQS. The 

emission thresholds that trigger requirements of the conformity rule are called de minimis

levels.
212

A determination of conformity with the applicable SIP is required for each pollutant where 

the total direct and indirect emissions in a non-attainment or attainment-maintenance area 

caused by the action would exceed de minimis levels. The General Conformity de minimis

thresholds are defined in 40 CFR 93.153(b) and in Rule 1501. In addition, the project 

proponent must demonstrate that the total direct and indirect emission increases associated 

with the action will not be regionally significant; that is, they will not represent 10 percent or 

more of an emission inventory or emissions budget of an area. 

The General Conformity rules do not apply to federal actions in areas designated as nonattainment of the CAAQS only.

Compliance with Air Quality Standards

Under the 1977 Amendments to the CAA, those states with air quality that did not achieve 

the NAAQS were required to develop and maintain SIPs. These plans constitute a

federally enforceable definition of the approach of the state (or “plan”) and schedule for the 

attainment of the NAAQS. Air quality management areas are designated as “attainment,” 

“non-attainment,” or “unclassified,” depending on whether or not they achieve the NAAQS 

and CAAQS. In addition, California can also designate areas as “transitional.” It is important 

to note that, because the NAAQS and CAAQS are different in many cases, it is possible for 

an area to be designated as attainment by EPA (meets the NAAQS) and “non-attainment” by 

the CARB (does not meet the CAAQS) for the same pollutant. Also, an area can be 

designated as attainment for one pollutant (e.g., NO2) and non-attainment for others (O3 and 

PM10).

Areas that were designated as attainment in the past, but have since achieved the NAAQS, 

are further classified as “attainment-maintenance.” The maintenance classification remains 

in effect for 20 years from the date that the area is determined by EPA to meet the NAAQS. 

There are numerous classifications of the non-attainment designation, depending on the 

severity of non-attainment. For example, the O3-nonattainment designation has seven 

subclasses: transitional, marginal, moderate, serious, severe-15, severe-17, and extreme. 

Areas that lack monitoring data are designated as unclassified areas and treated as attainment 

areas for regulatory purposes.

The SSAB, which coincides geographically with the desert region of Imperial and Riverside 

Counties, currently meets the federal and state standards for all pollutants except O3 and 

PM10. The SSAB is currently classified as a “moderate” PM-10-nonattainment area and 

transitional non-attainment area for O3. ISDRA is located within an attainment area for the 

federal and state CO, NO2, SO2, and Pb standards. The City of Calexico, located at the 

California/ Mexico International border, is in a non-attainment area for CO.

CARB monitors ambient air quality at approximately 250 air monitoring stations across the 

state. Air quality monitoring stations usually measure pollutant concentrations 10 feet above 

ground level; therefore, air quality is often referred to in terms of “ground-level” 

concentrations. Factors affecting ground-level pollutant concentrations include the rate at 

which pollutants are emitted to the atmosphere, the height from which they are released, the 
213

physical combination of emissions from various sources, the formation of secondary 

pollutants, the interaction of pollutants with topographic features, and meteorological 

conditions. Meteorological parameters that affected pollutant dispersion the most are wind 

speed and direction, atmospheric stability, mixing height, and temperature.

Ambient criteria air pollutant concentration in the SSAB are measured at six air quality 

monitoring stations operated by Imperial County APCD and CARB. The nearest air quality 

monitoring station operating in the vicinity of the Plan Area is a monitoring station located at 

Calexico East, approximately 20 miles to the southwest of the Plan Area. The station 

monitors O3, CO, NO2, SO2, PM10, and Pb. Data for the years 1996 to 2000 are summarized 

in Table 3.12-4. Over the last 5 years, the federal and state standards for NO2, SO2, and Pb 

have not been exceeded at the Calexico East Station. For the last 3 years, the federal and 

state 24-hour and annual standards for PM10 were exceeded every year. Ozone levels at the 

Calexico East Station exceeded federal and state standards in every year from 1996 to 2000. 

Please note that the monitoring data from the Calexico-East Monitoring station was 

invalidated by both CARB and U.S. EPA as of September 2001 due to its location near a 

road. 

Sources of Regional and Local Pollution

The most significant sources of O3, NO2, CO, and PM10 in SSAB are automobiles and OHVs. 

The greatest source (87 percent) of PM10 is road dust. Ozone is formed by the reaction of 

ROG and NOx, which are largely combustion products from gas and diesel engines. Ozone 

is a regional air pollutant because its precursors are transported and diffused by wind 

concurrently with ozone production. In Imperial County, 68 percent of the 310 tons per day 

of ROG emitted come from mobile sources (i.e., automobiles, trucks, marine vessels, aircraft, 

and heavy equipment). For NOx, 88 percent of the 240 tons emitted daily are from mobile 

sources. Some ozone levels in excess of the federal and state standards can be traced to 

emissions of ozone precursors transported by wind from the South Coast Air Basin and from 

Mexico. Computer modeling of smog formation has shown that a reduction of 

approximately 25 percent each of NOx and ROG would allow the SSAB to meet the federal 

O3 standard on days when there is no substantial transport of pollution from the South Coast 

Air Basin or other air shed (District, 1999).

High concentrations of PM10 in many areas in Imperial County result from wind action. The 

wind picks up particles from disturbed and undisturbed surfaces, recreational travel on paved 

and unpaved roadways, construction and demolition activities, and farming operations such 

as crop burning. These particles can remain suspended in the air for long periods and can 

travel a great distance. The principal health effect of airborne particulate matter is on the 

respiratory system.
214

Source: AIR Data, U.S. EPA Office of Air Quality Planning and Standards: Imperial County, CA 1996 - 2000. EPA website: 

http//www.epa.gov/air/data

Notes:

(a) Concentration units for ozone, carbon monoxide, nitrogen dioxide, and sulfur dioxide are in parts per million (ppm). 

Concentration units for PM10 and lead are in micrograms per cubic meter (μg/m3).

For annual standards, a value of 1 indicates that the standard has been exceeded.

(c) The number of days above the 8-hour ozone standard is not the number of violations of the federal standard for the year. The 

number of days is presented for display purposes until the EPA completes the 8-hour ozone monitoring evaluation program.

NM = Not Monitored.

N/A = Not applicable.

Emissions sources associated with the existing use of ISDRA consist of combustion 

emissions from OHVs; small internal-combustion generator engines; recreational vehicles 

and on-road motor vehicles (commuting to, delivery at, traveling inside, and departing from 

the site); and fugitive dust emissions entrained from vehicles traveling over paved and 

unpaved surface. The principal sources of criteria pollutant emissions are automobiles and 

recreational vehicles.

The South Coast Air Quality Management District (SCAQMD) recently released a draft 

report, referred to as theMultiple Air Toxics Exposure Study (SCAQMD, 1999), discussing 

the exposure risk to toxic air contaminants in Southern California. The report stated that 

about 70 percent of all estimated human health risk to toxic air contaminants is attributed to 

diesel exhaust (particulate emissions); about 20 percent to other toxic compounds associated 

with mobile sources such as benzene and 1,3-butadiene; and about 10 percent to stationary 

sources. Existing emitters of toxic air pollutants include automobiles, trucks, recreational 

vehicles, portable fuel storage tanks, and OHV rental stations. 

Table 3.12-4 Ambient Air Quality Summary, Calexico – East Monitoring Station

— Note data has been officially invalidated as this location may receive impacts due to its proximity to the road.

Maximum Concentrations (a)

Number of Days Exceeding 

Federal Standard (b)

Number of Days Exceeding 

State Standard (b)

Pollutant

Averaging 

Time

California 

Air 

Quality 

Standards

Federal 

Primary 

Standards 1996 1997 1998 1999 2000 1996 1997 1998 1999 2000 1996 1997 1998 1999 2000

Oxidants 

(Ozone)

1 hr 0.09 ppm 0.12 

ppm

0.162 0.121 0.236 0.156 0.108 3 0 1 3 0 22 6 27 13 7

8 hrs (c) N/A 0.08 

ppm

0.117 0.092 0.101 0.110 0.079 12 2 13 5 0 N/A N/A N/A N/A N/A

1 hr 20 ppm 35 

ppm

Carbon 22.0 21.0 18.4 14.0 17.6 0 0 0 0 0 1 1 0 0 0

Monoxide

8 hrs 9 ppm 9 ppm 8.74 16.29 13.00 9.37 11.30 0 2 3 0 1 0 4 3 1 1

Nitrogen 1 hr 0.25 ppm N/A 0.072 0.091 0.105 0.110 0.124 N/A N/A N/A N/A N/A 0 0 0 0 0

Dioxide Annual N/A 0.053 

ppm

0.007 0.011 0.011 0.013 0.012 0 0 0 0 0 N/A N/A N/A N/A N/A

1 hr 0.25 ppm N/A 0.036 0.035 0.026 NM NM N/A N/A N/A N/A N/A 0 0 0 N/A N/A

24 hrs 0.05 ppm 0.14 

ppm

0.010 0.015 0.009 NM NM 0 0 0 N/A N/A 0 0 0 N/A N/A

Sulfur 

Dioxide

Annual N/A 0.03 

ppm

0.001 0.002 0.003 NM NM 0 0 0 N/A N/A N/A N/A N/A N/A N/A

PM10 24 hrs 50 μg/m3150 

μg/m3

NM NM 568 1,342 1,613 N/A N/A 10 20 32 N/A N/A 44 51 57

Annual 30 μg/m350 

μg/m3

NM NM 107.8 168.7 238.8 N/A N/A 1 1 1 N/A N/A 1 1 1

Lead Quarterly 

Average

N/A 1.5 

μg/m3

0.05 0.03 0.03 0.02 0.02 0 0 0 0 0 N/A N/A N/A N/A N/A
215

3.13 Hazardous Materials

Introduction

This section evaluates the storage and use of hazardous materials and the disposal of nonhazardous and hazardous waste within the ISDRA. In addition, a discussion of applicable 

environmental regulations and the results from a search of applicable federal and State of 

California environmental databases is provided to provide a better understanding of the 

hazardous materials used and disposed of near the ISDRA. Existing effects to human health 

and the environment are discussed to provide a baseline from which the proposed project 

alternatives can be analyzed.

Current and Past Uses of Adjoining Property

As described in Section 3.5 (Land Use and Ownership), land uses proximate or adjacent to 

the ISDRA Planning Area include a number of non-recreation applications. These land uses 

include Bureau of Reclamation-withdrawn lands, military target areas, sand and gravel sales 

activities, geothermal leases, oil and gas leases, mining, and utility transportation rights-ofway. Although certain of these land uses have an undetermined potential for minor 

hazardous material releases or localized contamination, they are not of the type that typically 

would be expected to pose a substantial hazardous material-related threat to the surrounding 

environment.

Environmental Regulations

The storage and use of hazardous materials is governed by federal, state, and local laws, 

ordinances, regulations, and standards (LORS). Applicable laws and regulations that address 

the use and storage of hazardous materials are discussed below along with applicable laws, 

ordinances, regulations, and standards that address the storage, transportation, and disposal of 

non-hazardous and hazardous waste. 

CERCLA: Hazardous materials are governed under existing federal regulation through the 

Environmental Response, Compensation, and Liability Act (CERCLA), commonly knows as 

Superfund. This law provides broad federal authority to respond directly to releases or 

threatened releases of hazardous substances that may endanger public health or the 

environment. Title III of SARA, an amendment to CERCLA, requires states to establish a 

process for developing local chemical emergency preparedness programs and to receive and 

disseminate information on hazardous materials present at facilities in local communities. 

RCRA: The federal statute that controls both non-hazardous and hazardous waste is Resource 

Conservation and Recovery Act (RCRA), 42 USC Sections 6901, et seq., and its 

implementing regulations found at 40 CFR 260, et seq. Subtitle D makes the regulation of 

non-hazardous waste the responsibility of the states; federal involvement is limited to 

establishing minimum criteria that prescribe the best practicable controls and monitoring 

requirements for solid waste disposal facilities. SubtitleC controls the generation, 

transportation, treatment, storage, and disposal of hazardous waste through a comprehensive 
216

“cradle to grave” system of hazardous waste management techniques and requirements. It 

applies to all states and to all generators of hazardous waste (above certain levels of waste 

produced). EPA is responsible for implementing the law. The State of California laws for 

managing hazardous wastes is in Title 22 of the California Code of Regulations (CCR).

Health and Safety Code Section 25500 (Waters Bill): California Health and Safety Code, 

Section 25500, et seq., and the regulations to the law in 19 CCR Section 2620, et seq. require 

local governments to regulate local business storage of hazardous materials in excess of 

certain quantities. The law also requires that entities storing hazardous materials be prepared 

to respond to releases. The threshold quantities for hazardous materials are 55 gallons for 

liquids, 500 pounds for solids, and 200 cubic feet for compressed gases measured at standard 

temperature and pressure.

Health and Safety Code Section 25531 (La Follette Bill): California Health and Safety Code, 

Section 25531, et seq., regulates the registration and handling of acutely hazardous materials. 

Acutely hazardous materials are any chemicals designated as an extremely hazardous 

substance by EPA as part of its implementation of Superfund Amendments and 

Reauthorization Act (SARA) Title III. 

Aboveground Petroleum Storage Act: California Health and Safety Code Sections 25270 to 

25270.13 is intended to ensure compliance with the federal Clean Water Act. The law applies 

if a facility has an aboveground storage tank (AST) with a capacity greater than 660 gallons 

or a combined AST capacity greater than 1,320 gallons, and if there is a reasonable 

possibility that the tank(s) may discharge oil in “harmful quantities” into navigable waters or 

adjoining shore lands. 

Safe Drinking Water and Toxics Enforcement Act (Proposition 65): This California law 

identifies chemicals that cause cancer and reproductive toxicity, informs the public, and 

prevents discharge of the chemicals into sources of drinking water. Lists of the chemicals of

concern are published and updated periodically. The California Office of Environmental 

Health Hazard Assessment administers the Act.

Solid Waste: Nonhazardous solid waste is regulated by the California Integrated Waste 

Management Act (CIWMA) of 1989, found in Public Resources Code (PRC) Sections 

40000, et seq. This law provides an integrated statewide system of solid waste management 

by coordinating state and local efforts in source reduction, recycling, and land disposal 

safety. Counties are required to submit Integrated Waste Management Plans to the state. This 

law directly affects Imperial County and the solid waste hauler and disposal company that 

will collect non-hazardous waste. It also affects BLM to the extent that hazardous wastes are 

not to be disposed with solid waste.

Non-hazardous solid and liquid waste generated within the ISDRA is placed into one of three 

dumpsters located within the Plan Area. A waste removal company removes the dumpsters. 

The quantity of this waste is currently unknown. Solid and liquid hazardous materials and 

petroleum products are not allowed to be placed in the dumpsters. 
217

Imperial County Regulations: Local regulations relating to hazardous materials in Imperial 

County are managed by the environmental health agency of the county.

Environmental Database Results

A review of available environmental records was performed to determine and identify known 

hazards associated in the ISDRA planning area and adjacent properties. An electronic 

database report was obtained from Fidelity Information Services, prepared in accordance 

with the American Society for Testing and Materials practices, which include all reasonably 

ascertainable environmental records including state and federal sources. The list of records, 

including the approximate minimum search distances and the resulting number of sites found 

within the ASTM search distance, measured from the perimeter of the Plan Area, are shown 

in Table 3.13-1. Descriptions of the databases searched below are provided in the following 

paragraphs. No sites of sites of environmental significance were identified.
218

Table 3.13-1 Site Distribution Summary – Imperial Hills Sand Dunes Recreation Area

Agency/Database – Type of Records

Within 

? mile

? to 1⁄4 

mile

? to 1⁄2 

mile

1⁄2 to 1 

mile

A) Databases searched to 1 mile

EPA – NPL. National Priority List. 0 0 0 0

EPA – CORRACTS. (RCRA Corrective Action [w/o 

TSD]).

0 0 0 0

State – SPL. State equivalent priority list. 0 0 0 0

B) Databases searched to 1⁄2-mile

EPA – RCRA TSD. RCRA permitted treatment, 

storage, disposal facilities.

0 0 0 -

State – SCL. State equivalent CERCLIS list. 0 0 0 -

EPA – CERCLIS/NFRP. Sites currently or formerly 

under review by EPA.

0 0 0 -

STATE REG CO – LUST. Leaking Underground 

Storage Tanks.

0 0 0 -

STATE/REG/CO – SWLF. Permitted as SWLF, 

incinerators, or transfer stations.

0 0 0 -

STATE – DEED RSTR. Sites with deed restrictions. 0 0 0 -

STATE – CORTESE. State index of properties with 

hazardous waste.

0 0 0 -

STATE – TOXIC PITS. Toxic Pits cleanup facilities. 0 0 0 -

STATE – FINDS – Facility Index System. 2 0 0 -

USGS/STATE – WATER WELLS. Federal and State 

Drinking Water Sources.

4 0 0 -

US EPA TRIS – Toxic Release Inventory Database. 0 0 0 -

C) Databases searched to 1⁄4-mile:

State – UST. Registered underground storage tanks. 0 0 - -

State – AST. Registered aboveground storage tanks. 1 0 - -

D) Databases searched to ? -mile:

EPA – GNRTR. RCRA registered small or large 

generators of hazardous waste.

2 - - -

EPA - RCRA Violations – RCRA 

violations/enforcement actions.

0 - - -

STATE – SPILLS. State spills list. 2 - - -

Total Sites 10 0 0 0

The following is a brief summary of each database searched that resulted in known sites 

within or near the ISDRA planning area. The sites are plotted in Figure 3.13-1.
219

View Figure 3.13-1

Potential Hazards - 68Kb 
220

Blank page back
221

Facility Index System (FINDS) – The FINDS database is an inventory of all facilities that are 

regulated or tracked by EPA. These facilities are assigned an identification number that 

serves as a cross-reference for other databases in the EPA program system. A review of the 

database results indicates two FINDS sites were identified within the survey area. These 

sites are as follows:

Santa Fe Pacific Minerals, Mesquite Mine. The site is located along SR-78 in the eastern 

portion of the Plan Area.

Arid Operations, Inc. The site is located along SR-78 in the eastern portion of the Plan Area.

The report also includes a category of “unmapped” sites. Sites are included in the unmapped 

category when the database information is not accurate enough to positively identify the site 

locations. The unmapped facilities are noted as:

United States Department of Interior Laguna Field Office U.S. Government, RTE 1 Box 201, 

Winterhaven, CA 92283

Glamis Radio Repeater, Black Mountain, Glamis, CA 92248

United States Geological Survey Wells /WATER WELLS – The Groundwater Site Inventory 

(GWSI) database is maintained by the United States Geological Survey (USGS). The 

database contains information for over 1 million wells and other sources of groundwater that 

the USGS has studied, used, or documented during research. A review of the database results 

indicates four USGS WATER WELLS were identified within the survey area. These 

WATER WELLS are used by the USGS for research purposes, and are located in the 

northern, eastern, and southern portions of the planning area.

State-of-California AST – The database maintains a list of aboveground storage tanks. A 

review of the database results indicates one state AST site was identified within the survey 

area. The site is as follows:

Newmont Gold Company. This site is located along SR-78 in the eastern portion of the Plan 

Area.

GNRTR – The database maintains a list of RCRA-registered small or large generators of 

hazardous waste. A review of the database results indicates two GNRTR sites were identified 

within the survey area. The sites are as follows:

Santa Fe Pacific Minerals. The site is a registered small quantity generator and is located 

along SR-78 in the eastern portion of the Plan Area.

Arid Operations, Inc. The site is a registered small quantity generator and is located along 

SR-78 in the eastern portion of the Plan Area.
222

SPILLS – The database maintains a list of spills from the Emergency Response Notification 

System (ERNS). The ERNS is a national computer database system that is used to store 

information on the sudden or accidental or both release of hazardous substances, including 

petroleum, into the environment. The ERNS contains preliminary information on specific 

releases, including the spill location, the substance released, and the responsible party. A 

review of the database results indicates two ERNS sites were identified within the 

survey area. 

On July 3, 1991, 50 gallons of sodium cyanide solution were spilled at a site located along 

SR-78 in the eastern portion of the planning area. The origin of the spill was unknown, and 

no waterway was affected by the spill. Based on the report provided by Fidelity Information 

Services, no further monitoring or remedial action has been required. Therefore, this site has 

a low potential to affect existing conditions in the ISDRA Planning Area.

On June 26, 2000, 9,900 pounds of hydrogen cyanide emissions were released to the 

atmosphere at a site located along SR-78 in the eastern portion of the planning area. No 

other media was affected by the release. The origin of the release was not given. Due to the 

time that has elapsed since the release, the site has a low potential to affect existing

conditions at the ISDRA. Based on the EDR provided by Fidelity Information Services, no 

further monitoring or remedial action has been required. Therefore, this site has a low 

potential to affect existing conditions in the ISDRA planning area.
223

3.14 Geology, Energy, and Mineral Resources

This section establishes the existing geologic conditions, including general seismicity, as 

well as energy and mineral resources. The local and regional geologic setting of the 

Algodones Dunes Area was researched using previous environmental assessment reports, soil 

reports, federal geographic information system (GIS) database maps, and technical research 

papers on the California desert. 

Soils and Geological Conditions

The soil and geologic conditions of the ISDRA planning area are summarized in this section, 

including a general description of the geologic setting earth materials and the geologic (dune) 

structure. The geologic study of the ISDRA planning area includes evaluation of surface 

soils.

General Description of Geologic Setting

The Imperial Sand Dunes (also known as the Algodones Sand Dunes) are the largest mass of 

sand dunes in California. This dune system extends for more than 40 miles along the eastern 

edge of the Imperial Valley agricultural region in a band averaging 5 miles in width. It is 

roughly bordered on the west by the Coachella Canal, which delivers Colorado River water 

to the fertile agricultural valley to the north. A major east-west route of the Union Pacific 

Railroad skirts the eastern edge.

The dune system is situated on a relatively flat plain that has an elevation of approximately 

50 feet above sea level. On the west, the plain is called East Mesa (because it is east of 

Imperial Valley). On the east, the plain is called Pilot Knob Mesa.

The dunes reach heights of 300 feet above the plain, and include classic examples of several 

different types of dunes. The sand dunes are thought originally to have been beach sands of 

ancient Lake Cahuilla, which occupied the Imperial Valley at a time when the Colorado 

River emptied into it instead of the Gulf of California. Unlike some major dune systems that 

have formed next to a mountain range, the Imperial Dunes have formed here primarily as a 

result of opposing seasonal winds. Winter winds come from the northwest, but often reverse 

to the southeast in summer. The stronger winter winds are slowly pushing the dune system 

southeastward.

The east and west sides of the dunes system differ substantially in character. West side sands 

are composed of material that is generally heavier and coarser than the lighter, finer sands 

carried further east in the prevailing winds. The coarse sands form the largest, tallest dunes, 

located in the western two-thirds of the dune system. These constitute the “primary dunes.” 

The tallest dunes are found toward the center of the overall dune mass, in the eastern half of 

the primary dune area. East of the primary dunes are the “secondary dunes,” smaller dunes 

composed of finer sands and having more vegetation cover (BLM, 1987). 
224

Geologic Structure

The ISDRA planning area includes a great variety of dune forms, but is dominated by 

prominent transverse ridges. Some consider the Algodones Dunes to be a chain of over-size 

barchans, whose horns join. Barchan dunes are crescent in shape, develop on a flat surface, 

with a moderate sand supply transported mostly by unidirectional winds. The dominant 

sand-driving winds in this area blow from the northwest to the southeast, parallel to the gross 

trend of the Algodones Dunes. Barchans can advance across the desert, horns first, at rates 

varying from a few inches to tens of feet per year, depending upon the size of the dune and 

the amount of erosion due to wind, water, and vehicles. The source of the dunes is most 

likely from the northwest, developed from a large plume of sand driven inshore from the 

beaches of ancient Lake Cahuilla, which once occupied the present location of the 

Salton Basin. 

In the southwest part of the Algodones Dune area are several long (about 6miles) examples 

of seif dunes. Seif dunes are formed when the sand-driving winds come from several 

directions, but within narrow limits, 15 to 20 degrees, and the barchan form becomes 

elongate and hook-shaped, forming the linear sand ridges or “seif” dunes, as cross winds 

come from wider and wider angles. These linear ridges rise approximately 30 feet or so 

above the dune mass and form distinct ridges that curve and fade into the main dune mass to 

the north.

Of all the California Dunes, the Algodones Dunes show the most evidence of age. They have 

a distinctive light brown color, much darker than younger pale gray or white sands of the 

Coachella Valley near Palm Springs toward the northwest. The darker color suggests that the 

Algodones Dunes have been around for a long time, probably dating back to the latter part of 

the Pleistocene, 10 to 20 thousand years ago, or longer (Norris-Sand Dunes of the California 

Desert).

Heavy vehicle use in the Algodones Dunes has modified some of the smaller dune forms 

(Norris, Sand Dunes of California). One of the most interesting dune areas geologically is 

the southern portion of the ISDRA, on either side of I-8. It is in this area that the greatest 

array of dune forms occurs. Vehicle disturbances change the small-scale dune forms, such as 

ripples, sand shears, and dune crests. Concentrations of heavier coarse- grained materials are 

apt to be displayed imperfectly as a result of vehicle disturbance unless strong winds have 

occurred just prior to observation of the dunes.

The Algodones Dunes have a scientific value and are used as a teaching and research area. 

The southern portion of the study area has the greatest array of geological features. North of 

I-8, the finest examples of seif dunes occur, as well as some interesting elongate sand ridges 

extending from the mega-barchans.

Sand and Soils

A soils report was written for Imperial County by the U.S. Department of Agriculture Soil 

Conservation Service (October 1981). The geographic limits of the soil report investigation 

ended along the western edge of the Algodones Dunes Area. No detailed soil information 

was found for most of the ISDRA planning area east of the western edge. Based on findings 
225

from the soil report, the western edge of the study area is composed primarily of Rositas 

sands with lesser areas of Antho loamy fine sands/Holtville silty-clay loams.

The Rositas sands are distributed throughout the ISDRA. These sands range in properties 

from loamy fine sands, to fine sands, to medium sands. The larger-grained Rositas sands are 

mostly in the western, upwind section of the subject area with the finer sands located mostly 

on the eastern downwind side of the dunes area. Typically, the Rositas sands are stratified, 

with reddish yellow to light brown coloring. These sands are formed in alluvial or eolian 

deposits from distant sources. Typically, the surface layer of the Rositas soil is light brown, 

loamy, fine sand about 4 inches thick. The underlying material is pinkish and very pale 

brown sand to a depth of 60 inches and can have thin gravelly subsurface layers. In many 

places, there are soils that have a sandy profile and a few thin lenses of fine sandy loam, silt 

loam, or silty clay loam. Permeability is rapid, and available water capacity is low. Surface 

runoff is slow, and there is a high hazard of soil blowing and abrasion to young plants. The 

effective rooting depth is 60 inches or more. 

The Antho loamy fine sands/Holtville silty-clay loams are found in smaller pocket areas, 

most of which lie south of SR-78 and just east of the Coachella Canal. These soils are deep 

and well drained and typically form in alluvial sediments of mixed sources. Surface textures 

are composed of fine sandy loam, silty loam sand, and silty-clay loam. Typically, the surface 

layer of this Antho/Holtville soil is reddish loamy fine sand about 13 inches thick. 

Underlying this is reddish yellow or pink fine sandy loam to a depth of 42 inches. Below this 

is stratified, contrasting material of finer or coarser texture. Permeability of the loamy sands 

is moderately rapid, and available water capacity is low to moderate. Permeability of the 

silty-clay loams is moderately slow, and available water capacity can be high. Surface runoff 

is slow, and the hazard of soil blowing for the sandy loam is high. The effective rooting 

depth is 60 inches or more. These soils have potential for irrigated farming with land 

leveling (USDOA, 1981).

Seismicity

Faults are fractures in the crust of the earth along which bedrock is displaced or offset as a 

result of pressures within the earth. An active fault is one where displacement has occurred 

within the last 11,000 years or so, which is a period in time that is referred to as the Holocene 

Epoch.

Earthquakes are vibrations of the earth caused by sudden movement of the bedrock on either 

side of an active fault. The vibration of the earth results when bedrock on either side of the 

fault breaks loose from its original position and then snaps into a new position. In the process 

of rebounding, vibrations called seismic waves are generated. The primary effect of 

earthquakes is the violent ground motion accompanying movement along a fault. Secondary 

effects include ground rupture; landslides; tsunamis (i.e., tidal waves); lurching; regional or 

local subsidence of the land; and liquefaction. Liquefaction is a geologic process in which 

soil that is saturated loses its strength or stiffness as a result of increased pore pressures 

resulting from ground shaking during earthquakes. Liquefaction is most likely to occur in 

recent geologic deposits, especially sandy soils that have a high groundwater table.
226

The planning area is located to the east of the zone of major historic recorded seismic activity 

in Southern California. The western portion of Southern California is more seismically active 

because of the basic differences in the geological environment between the western and 

eastern portions of Southern California. In addition, the number and length of the active 

faults decrease from west to east within the western portion of Southern California. 

The Imperial Valley is at the southern end of the San Andreas fault system, probably the 

most studied and best known fault system in the United States. The San Andreas system 

transects the northeastern margin of the Imperial Valley approximately 60 miles northwest of 

the Plan Area. Other major Holocene Epoch faults within the region include several faults 

that parallel, or are “en echelon” to, the southern section of the San Andreas fault. Most 

notably, these faults are the reported East Mesa fault, the East Highline Canal lineament, the 

Imperial-Brawley Seismic Zone, the Superstition Hills fault (San Jacinto fault Zone), and the 

Elsinore fault. Some geologic references for the area also indicate the possible existence of a 

postulated fault (Sand Hills fault) beneath the Algodones Sand Dunes, which may represent 

the inactive eastern boundary of the Salton Trough spreading center. No evidence has been 

documented to indicate that the Sand Hills fault has been active in Holocene time. The 

active faults currently associated with the eastern boundary of the Salton Trough are now 

coincident with the East Mesa fault and possibly the East Highline Lineament (Imperial 

Environmental Impact Statement, 1997).

Energy Resources

As of 1987, several oil and gas leases had been issued, mainly in the class L (limited use) 

area of the central dunes, the Glamis/Gecko Open Area, and in the North Algodones Dunes 

Wilderness. Leasing took place within the WSA in 1981 and 1982, prior to a moratorium on 

WSA leasing. Development of oil and gas resources is low due to geologic conditions.

Two Known Geothermal Resource Areas (KGRAs) underlie the recreation area, the Glamis 

KGRA and the Dunes KGRA. Figure 3.14-1 shows these areas. The geothermal potential is 

considered fair for high temperature electrical power generation and excellent for low 

temperature applications. The Glamis KGRA occupies a corridor along SR-78, extending up 

to 2 miles north and 3 miles south of the highway. The northern portion of the “Glamis” 

KGRA extends into the North Algodones Dunes Wilderness. The “Dunes” KGRA occupies 

16 sections of East Mesa and adjacent dunes in the southern portion of the Plan Area.

Mineral Resources

The principal mineral resources are sand and gravel. The blow sand of the main dune system 

is occasionally used for fill material. Alluvial sand and gravel deposits east of Glamis are 

extracted for road base material. Permits for the extraction of sand and gravel have been 

proposed for Class I land, not WSAs or Class L land. All sand and gravel sales activity is 

found on the Glamis-Boardmanville Class M lands. Mining claims are also located in the 

Class M lands. No mineral extraction has occurred in these areas, and potential for practical 

extraction appears to be low (BLM, 1987; CDC, 1980).
227

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Known Geothermal Areas - 68Kb 
228

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230

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231

CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

The environmental impacts associated with implementation of the project alternatives are 

described in the following sections. Impacts include both direct impacts and indirect 

impacts. A direct impact is caused by the action and occurs at the same time and place. 

Indirect impacts result from one or more of the direct impacts of the action, but may occur 

later in time or be further removed from the Plan Area. In addition, all impacts are 

considered adverse unless noted as beneficial. Where applicable, mitigation measures are 

provided to avoid, reduce, or compensate for project impacts. 

The following sections detail the anticipated impacts associated with each of the project 

alternatives, based on 14 distinct, but interrelated, resource categories. These include:

- Recreation (Section 4.1)

- Biological Resources (Section 4.2)

- Law Enforcement and Public Safety (Section 4.3)

- Social (Section 4.4)

- Economics (Section 4.5)

- Land Use and Land Ownership (Section 4.6)

- Visual Resources (Section 4.7)

- Water Resources (Section 4.8)

- Cultural Resources (Section 4.9)

- Transportation and Traffic (Section 4.10)

- Noise (Section 4.11)

- Air Quality (Section 4.12)

- Hazardous Materials (Section 4.13)

- Geology, Energy, and Mineral Resources (Section 4.14)
232

4.1 Recreation Resources

Introduction

This section assesses impacts to recreational resources as a result of implementing the 

alternatives described in Chapter 2 of this EIS. Alternative 1 (No Action) represents the 

management actions in the 1987 RAMP. The action alternatives (Alternatives 2, 3, and 4) 

provide different levels of developed recreation settings and improvements in accordance 

with designated ROS classes for each alternative. 

Direct and Indirect Effects 

The EIS alternatives are designed to provide varying mixes of recreation settings, varying 

types and amounts of other resource emphases, and varying recreation management standards 

and philosophies. This variation results in the alternatives having different effects on:

- The amount and quality of recreational opportunity available;

- Anticipated and potential recreation visitation levels; and

- Current management problems identified by visitors and managers that degrade 

recreation experiences.

Effects on Recreation Activities

Alternatives would affect recreation opportunities primarily through the recreation setting 

each alternative provides and the types and amounts of other resource emphases each 

prescribes (see table below). Recreation settings, as identified in the recreation opportunity 

spectrum system of classification, set standards for the type and amount of acces and s

facilities provided, recreation activities (experiences) provided, and management control and 

information provided.
Effects of the action alternatives on various recreation opportunities within the planning area.

Alternatives

Management Area #2 Recreation and 

Resource Protection #3 Natural/Cultural #4 Recreation

Name Acreage %

OHV designation

MUC designation

ROS Class

OHV designation

MUC designation

ROS Class

OHV designation

MUC designation

ROS Class

Mammoth Wash 8,105 5% Open L SPM Closed C SPNM open M RN

N. Algodones Dunes 

Wilderness 26,202 16% Closed C SPNM Closed C SPNM closed C SPNM

Gecko 21,225 13% Open I R Open M RN open I U

Glamis 24,041 15% Open M RN Open L SPM open I R

Adaptive 

Management Area 33,289 21% Limited L SPM Closed C SPNM limited L RN

Ogilby 21,710 14% Open M RN Open L SPM open M R

Dune Buggy Flats 16,658 10% Open M RN Open L SPM open I R

Buttercup 7,842 5% Open I R Open M RN open I U

 Total Acres 159,072

Note: The 1987 RAMP did not designate management areas; therefore, it was not comparable in this table.

I – Intensive C – Controlled RN – Roaded Natural

M – Moderate U – Urban SPM – Semi-primitive Motorized

L - Limited R – Rural SPNM – Semi-primitive Non-motorized
234

blank
235

Mix of Recreation Settings

The mix of recreation settings would affect the types and amounts of specific recreation 

opportunities and experiences available at the ISDRA. Alternative 4 would provide higher 

levels of rural and urban settings and would increase opportunities for activities such as 

overnight camping, OHV recreation, socializing, scenery from a developed site, and visiting 

interpretive sites. There would be more opportunity to experience the ISDRA in a low risk 

way with the security of designed, managed facilities, and many other visitors nearby.

Alternative 3 would provide higher levels of semi-primitive motorized and semi-primitive 

non-motorized settings in the ISDRA. Semi-primitive non-motorized settings would include 

more opportunity for activities such as hiking, and horseback riding. While semi-primitive 

motorized setting would provide more opportunity for OHV recreation with very little 

contact with other visitors. Both settings would provide a relatively remote and minimally 

disturbed natural setting with few to moderate numbers of visitors and few management 

controls. Semi-primitive settings allow the public to experience the ISDRA in a high risk, 

self-reliant manner.

N. Algodones

 Dunes Wilderness

16%

Mammoth

 Wash

5%

Gecko

13%

Buttercup

5%

Dune Buggy

 Flats

10%

Ogilby

14%

Adaptive 

Management Area

22% Glamis

15%

Chart 4.1 - Management area percentage within the planning area
236

Alternative 2 (preferred alternative) would provide a mixture of Alternatives 3 and 4. This 

alternative would increase developed camping, limited OHV areas, and interpretive sites. It 

would also decrease OHV open areas and dispersed camping. It would provide both high 

and low risk experiences throughout the recreation area. This alternative would sustain a 

wide range of recreation opportunities throughout the ISDRA while meeting conservation 

goals. 

Assumptions and Assessment Guidelines

The management actions that would occur under all action alternatives (e.g., new and 

improved facilities, improved public safety measures, and public information encouraging 

off-peak visits) are expected to improve the overall quality of experience at ISDRA. 

Management actions in all action alternatives are also expected to decrease the amount of 

open OHV recreation areas due to the establishment of an Adaptive Management Area.

The estimated range of future visits to the ISDRA for the implementation period of the 

proposed revised RAMP (i.e., approximately 10years) under each alternative is provided in 

Table 4.1-1. These estimates are based upon visitor use data from the 1999/2000 visitation 

season. As noted in Section 3.1, the 1999/2000 season represents the baseline condition for 

visitor attendance because it is consistent with the management of ISDRA under the 1987 

RAMP (i.e., prior to implementation of the temporary closures).

Since 1985, the number of visits at the ISDRA has approximately tripled (BLM, 2001q). (A 

“visit” is defined in the footnotes of Table 4.1-1.) This increase in visitor use represents an 

annual growth rate of approximately 7.5 percent since 1985. In comparison, the State of 

California Department of Parks and Recreation has estimated growth in statewide OHV 

activity of approximately 3.5 percent annually (California Department of Parks and 

Recreation, 1997). These two percentages comprise the high and low ends of the range of 

projected increases in visitation at ISDRA under the No Action Alternative (Alternative 1), 

as shown in Table 4.1-1. 

Under the action alternatives (2, 3, and 4), law enforcement is proposed to be increased from 

the No Action condition for the six major holiday weekends. This management action is 

expected to result in a decrease in visitation by visitors who engage in unlawful activities. 

This initial decrease in visitor use, however, would be offset by other management actions 

intended to improve the overall quality of experience at ISDRA (e.g., new and improved 

facilities, improved public safety measures, public information encouraging off-peak visits, 

etc.), that are expected to attract visitors seeking OHV recreational experiences consistent 

with legal activities. For the purposes of analysis in this EIS, the lower end of the projected 

visitor-use growth range under the action alternatives is assumed to be similar to the 

statewide average (i.e., 3.5 percent). For each of the action alternatives (Alternatives 2, 3, and 

4), the high end of the projected visitor-use growth range limit would be comparable to the 

historical growth rate experienced since 1985; but the actual increase in visitor use would be 

constrained by the availability of camping facilities and management actions designed to 

maintain a recreation experience associated with a specific ROS class.
237

The high end of the growth range under Alternative 2 is assumed to be 5 percent (i.e., the 

approximate mid-point of the 7.5 percent growth rate experienced annually at ISDRA since 

1985 and the state projection for growth in OHV use of 3.5 percent).

Under Alternative 3, revising the ROS classification of the Adaptive Management Area is 

expected to limit the growth of OHV-related visitor use because the change in classification 

would exclude motorized vehicle use. The upper growth limit under Alternative 3 is, 

therefore, assumed to average 4 percent annually. 

Alternative 4 is expected to result in a higher growth in visitation than the other action 

alternatives because the change in ROS class under that alternative would allow for 

additional campgrounds in the Glamis Management Area. On this basis, the anticipated high 

end of the growth range under Alternative 4 is assumed to average 6 percent annually. 

TABLE 4.1-1 VISITOR USE PROJECTIONS (2002-2003 TO 2012-2013)

Projected Visits 

(2012-2013 Season)3

Baseline Visits

(1999-2000 Season)

Estimated Visits 1

(2002-2003 Season)2

Low Range High Range

Alternative 1 867,753 1,005,000 1,418,000 2,071,000

Alternative 2 867,753 1,005,000 1,418,000 1,637,000

Alternative 3 867,753 1,005,000 1,418,000 1,488,000

Alternative 4 867,753 1,005,000 1,418,000 1,800,000

1

A “visit” occurs when one person visits BLM lands to engage in any recreation activity, whether for a few minutes, full 

day, or more. 2

The estimate for the 2002-2003 season is based on an average 5 percent growth rate from the baseline season (1999-

2000).

3

This projection is the expected change in visitation between the 2002-2003 season and the 2012-2013 season. This 

represents the first season following implementation of a revised RAMP and 10years later (i.e., the proposed period of 

implementation for a revised RAMP).

For this analysis of recreational resources, the assessment focuses on the ROS classifications 

as they pertain to the action alternatives. The proposed ROS classifications for the action 

alternatives (Alternatives 2, 3, and 4) are described in Chapter 2. For Alternative 1, the BLM 

has not assigned any ROS classifications because a ROS inventory of the lands within the 

ISDRA has not yet been conducted. The discussion of each action alternative focuses on the 

following:

- The change in ROS designation, when compared to the baseline condition

- The expected increase in visitation and the visitor supply of the eight management areas

For Alternative 1, the assessment focuses on continued implementation of the 1987 RAMP 

and baseline conditions (excluding the interim closures).
238

Alternative 1

This alternative would not affect the current status of the North Algodones Dunes Wilderness 

Area, which prohibits mechanized use within its boundaries, but allows non-mechanized 

recreation use. Under Alternative 1, no ROS classes are designated.

Although visitors would continue to congregate at high-use areas under Alternative 1, it is 

likely that there would be some change to existing visitor use patterns (i.e., the spatial 

distribution of recreation visits at ISDRA). As noted above in Table 4.1-1, annual visitation 

in 2002-2003 is expected to be approximately 1,005,000; by 2012-2013 annual visitation 

would grow to an estimated 1,418,000 to 2,071,000. This increase in visitation is likely to 

result in the dispersal of visitors, thereby increasing the concentration in areas that currently 

maintain a lower number of visitors. As a result, compatibility issues may arise between 

those users seeking a more solitary experience and those users dispersed into lower-use areas 

due to overcrowding. This is considered a potentially adverse impact of Alternative 1.

Increased visitation would present various management challenges for ISDRA staff, 

including those involving public safety. This issue is addressed further in Section 4.3 (Law 

Enforcement and Public Safety).

Implementation of this alternative would also provide for some recreation improvements, as 

outlined in the 1987 RAMP. These improvements include installation of signs; development 

and distribution of brochures; presentation of evening programs in the Gecko, Glamis, or 

Buttercup areas; development of a vehicle corridor along the Old Coachella Canal; 

establishment of Osborne Lookout as an interpretive site (and eventually to a day-use 

facility); various improvements at the camping areas; improvements to the Cahuilla Ranger 

Station; developed camping areas and access in the Mammoth Wash Open Area; and 

provisions for increasing visitor and staff safety at ISDRA. These improvements would 

provide a beneficial impact to visitors.

Alternative 2

ROS Designations

Implementation of Alternative 2 would result in the designation of individual ROS categories 

to each of the eight management areas in the Plan Area. Table4.1-2 provides a breakdown 

of the acreage and a description of the type of recreation experience that characterizes each 

ROS class designation. 
239

TABLE 4.1-2 ROS CLASS ACREAGE AND DESCRIPTION

ALTERNATIVE 2

ROS Class

&

Management 

Area Description

Designated 

Acreage

Rural

Gecko

Buttercup

Indicates that the area is characterized by a natural environment that 

has been modified substantially by development of structures, 

vegetative manipulation, or pastoral agricultural development. 

Resource modification and utilization practices may be used to enhance 

specific recreational activities and maintain vegetative cover and soil. 

Sights and sounds of humans are readily evident, and the interaction 

among users is often moderate to high. Many facilities are designed for 

use by a large number of people, and facilities often are provided for 

special activities. Moderate user densities are present away from 

developed sites. Facilities for intensified motorized use and parking are 

available.

29,067

Roaded Natural

Glamis

Ogilby

Dune Buggy

Indicates that the area is characterized by a predominantly naturalappearing environment with moderate evidence of the sights and 

sounds of humans. Such evidence usually harmonizes with the natural 

environment. Interaction among users may be moderate to high, with 

evidence of other users prevalent. Resource modification and utilization 

practices are evident, but harmonize with the natural environment. 

Conventional motorized use is allowed and incorporated into 

construction standards and design of facilities.

62,409

Semi-Primitive 

Motorized

Mammoth Wash

AMA

Indicates that the area is characterized by a predominantly natural or 

natural-appearing environment of moderate to large size. Concentration 

of users is low, but there is often evidence of other users. The area is 

managed in such a way that there are minimum onsite controls, and 

restricted use of local primitive or collector roads with predominantly 

natural surfaces and trails suitable for OHVs is permitted.

41,394

Semi-Primitive 

Non-Motorized

North Algodones 

Dunes 

Wilderness

Indicates that the area is characterized by a predominantly natural or 

natural-appearing environment of moderate to large size. Interaction 

among users is low, but there is often evidence of other users. The area 

is managed in such a way that minimum onsite controls; and 

restrictions may be present, but would be subtle. Motorized recreation 

use is not permitted, but local roads used for other resource 

management activities may be present on a limited basis.

26,202

Total 159,072

Under Alternative 2, management actions would be applied to ensure that the recreation 

experience at ISDRA was consistent with the ROS class designated to each of the nine 

management areas. Management actions to be applied under Alternative 2 in support of the 

ROS designations include facility development and actions to ensure that the visitor supply 

(discussed below) at ISDRA is not substantially exceeded. The anticipated results are the 
240

conservation of unique recreation opportunities afforded by ISDRA, and natural and cultural 

resources. This is considered a beneficial impact.

Visitor Supply

The estimated visitor supply at ISDRA is provided in Table4.1-3. The visitor supply is 

defined as the maximum number of visitors that could occur at ISDRA while maintaining the 

designated ROS class goals.

TABLE 4.1-3 VISITOR SUPPLY BY MANAGEMENT AREA 

Area

DESIGNATED

ROS CLASS Visitor Supply A

Gecko Management Area Rural 28,199

Buttercup Management Area Rural 19,165

Mammoth Wash Management Area Semi-Primitive 

Motorized 2,829

Glamis Management Area Roaded Natural 12,688

Ogilby Management Area Roaded Natural 9,696

Dune Buggy Flats Management Area Roaded Natural 7,793

North Algodones Dunes Management Area Semi-Primitive 

Non-Motorized 74

Total NA 80,444

aThe visitor supply presented is based on the acreage available for camping, the number of 

available campsites, an average number of vehicles per camping party, and an average 

number of people per vehicle.

Historically, visitation during major holiday weekends has often exceeded 100,000 visits 

(BLM, 2001q). This level of visitation far exceeds the visitor supply at ISDRA, as defined 

above in Table 4.1-3. However, over the course of the recreation season at ISDRA (October 

1 through May 31), the total annualized visitor supply is expected to be adequate. 

Management actions can be expected to redistribute visits to weekends other than the major 

holiday weekends, this may represent an impact to recreation resources because it could alter 

the recreation experience at ISDRA. Impacts may occur if groups of friends and family 

cannot camp together due to visitation dispersion over time. Some members of the public 

may want to visit on non-holiday weekends and their friends and family may not have a 

choice as to when they can come. The maintenance of designated ROS classifications 

through management actions would provide a beneficial impact to recreation by preserving 
241

the unique quality of experience provided at ISDRA (e.g., Semi-Primitive Motorized and 

roaded natural ROS classes). However, at the same time, it may have a negative sociological 

impact to the visitors who could be displaced or no longer acquire the historical experience 

provided in Alternative 1.

Other Management Actions

This alternative would include updating the kiosks at the Wildlife Viewing Area. This would 

provide a beneficial impact to the public who seek interpretive information on recreational, 

natural, and cultural resources.

Applying a dust palliative on the Wash Road has the potential to reduce the dust and, 

therefore, improve the quality of the recreational experience in that area.

This alternative would provide for the development of pit toilet facilities in Glamis Flats, The 

Washes, and Dune Buggy Flats areas. This would provide an amenity to visitors and is 

considered a beneficial impact.

The potential curfew at Oldsmobile Hill, Competition Hill, Competition Hill South Dunes, 

Test Hill, and Patton Valley at night would eliminate a recreational opportunity that is 

offered in the baseline condition and have a negative impact to recreation. There has been 

historical visitation in these areas since the 1950’s and 1960’s. Many people who visit the 

Dunes look forward to these areas as destination points and for legal social and OHV 

activities.

The potential alcohol ban could have a negative impact on the social experience of law 

abiding visitors although improve the overall safety of all visitors.

In the Buttercup Management Area, interpretive facilities and parking would be developed 

near Grays Well Road and a law enforcement/ranger station facility would be constructed. 

These facilities would provide an amenity to visitors, and would have a beneficial impact.

Vendors would be allowed to continue to vend in specific locations in the recreation area and 

short term and long-term areas would be established. This is considered to be beneficial for 

visitors.

The Adaptive Management Area (AMA) would be changed from open to limited OHV use 

and have a seasonal closure. Visitors who historically used this low use area will now have 

to obtain a permit in order to gain legal access into the AMA. This would have a negative 

impact on OHV recreation. 

Stronger enforcement of riding (speeding) near concentrations of people could improve the 

camping experience through out the ISDRA.

The fee demo plan would be revised and fees could increase. This could have a negative 

impact on the recreational experience, and low-income families. Although, fees collected 

and used in the ISDRA could have a beneficial impact on recreation by providing more 

facilities and services.Adding fee-free weekends could mitigate a negative experience, and 

the increasing level of available funds will add to our ability to continue to support the 

recreational activities.
242

Alternative 3

ROS Designations

Implementation of Alternative 3 would result in the designation of individual ROS categories 

to each of the eight management areas in the Plan Area. Table4.1-4 provides a breakdown 

of the acreage and a description of the type of recreation experience that characterizes each 

ROS class designation. 

TABLE 4.1-4 ROS CLASS ACREAGE AND DESCRIPTION

ALTERNATIVE 3

ROS CLASS

&

Management 

Area Description

Designated 

Acreage

Roaded Natural

Gecko

Buttercup

Indicates that the area is characterized by a predominantly naturalappearing environment with moderate evidence of the sights and 

sounds of humans. Such evidence usually harmonizes with the natural 

environment. Interaction among users may be moderate to high, with 

evidence of other users prevalent. Resource modification and utilization 

practices are evident, but harmonize with the natural environment. 

Conventional motorized use is allowed and incorporated into 

construction standards and design of facilities.

29,067

Semi-Primitive 

Motorized

Glamis

Ogilby

Dune Buggy

Indicates that the area is characterized by a predominantly natural or 

natural-appearing environment of moderate to large size. Concentration 

of users is low, but there is often evidence of other users. The area is 

managed in such a way that there are minimum onsite controls, and 

restricted use of local primitive or collector roads with predominantly 

natural surfaces and trails suitable for motorbikes is permitted.

62,409

Semi-Primitive 

Non-Motorized

Mammoth Wash

North Algodones 

Dunes 

Wilderness

AMA

Indicates that the area is characterized by a predominantly natural or 

natural-appearing environment of moderate to large size. Interaction 

among users is low, but there is often evidence of other users. The area 

is managed in such a way that minimum onsite controls and restrictions 

may be present, but would be subtle. Motorized recreation use is not 

permitted, but local roads used for other resource management 

activities may be present on a limited basis.

67,596

Total 159,072

Under Alternative 3, management actions would be applied to ensure that the recreation 

experience at ISDRA was consistent with the ROS class designated to each of the nine 

management areas. Compared to Alternative 2, Alternative 3 would provide an increased 

area available for semi-primitive recreation experiences, including semi-primitive non-
243

motorized, which would constitute more than half of the Imperial Sand Dunes Planning Area 

under this alternative, a decrease in roaded natural, and the elimination of the rural 

classification.

Management actions to be applied under Alternative 2 in support of the ROS designations 

include facility development and actions to ensure that the visitor supply (discussed below) at 

ISDRA is not substantially exceeded, and will apply in alternative 3. The anticipated result 

is the conservation of natural and cultural resources in ISDRA. The decrease in acreage 

available for off-highway vehicle recreation and available camping acreage is considered a 

substantial negative recreational impact.

Visitor Supply

The estimated visitor supply at ISDRA under this alternative would be lower than that 

available under Alternative 2. This is due to the increased acreage designated as semiprimitive, which is associated with a lower concentration of visitors. Please see Table 4.1.5

TABLE 4.1-5 VISITOR SUPPLY BY MANAGEMENT AREA 

Area

DESIGNATED

ROS CLASS Visitor Supply A

Gecko Management Area Roaded Natural 6,453

Buttercup Management Area Roaded Natural 5,084

Mammoth Wash Management Area Semi-Primitive 

Non-Motorized 23

Glamis Management Area Semi-Primitive 

Motorized 3,806

Ogilby Management Area Semi-Primitive 

Motorized 2,909

Dune Buggy Flats Management Area Semi-Primitive 

Motorized 2,337

North Algodones Dunes Management Area Semi-Primitive 

Non-Motorized

74

Total NA 20,686

aThe visitor supply presented is based on the acreage available for camping, the number of 

available campsites, an average number of vehicles per camping party, and an average 

number of people per vehicle.

Historically, visitation during major holiday weekends has often exceeded 100,000 visits 

(BLM, 2001q). Because the total area available for OHV use under Alternative 3 would be 
244

less than half of that available under Alternative 2, the visitor supply is anticipated to be 

reduced proportionately. Assuming that the visitor supply under Alternative 3 is 

approximately 50 percent of that available under Alternative 2, the visitor supply would be 

exceeded on major holiday weekends. This represents an adverse impact to recreation 

resources.

The implementation of management actions designed to maintain the semi-primitive nonmotorized ROS class at ISDRA would provide a benefit to the visitors not engaging in 

motorized vehicle activity. 

Other Management Actions

Impacts related to other management actions (e.g., facility development, nighttime closures, 

etc.) would be similar to those discussed previously under Alternative 2. 

Under this alternative, the current ranger station, Cahuilla Ranger Station, would be moved to 

Osborne Outlook. This alternative will close the existing camping area at Osborne Overlook 

and will negatively impact the OHV enthusiasts who have historically camped there. 

However, the beneficial effects to visitors to the area could offset this impact. This facility 

would provide a central location for emergency services during the visitation season. It 

would also serve as an interpretive facility for both motorized and non-motorized recreation 

visitors. 

Alternative 4

ROS Designations

Implementation of Alternative 4 would result in the designation of individual ROS categories 

to each of the eight management areas in the Plan Area. The specific ROS designations and 

acreages associated with this alternative are depicted in Table4.1-6. 
245

TABLE 4.1-6 ROS CLASS ACREAGE AND DESCRIPTION

ALTERNATIVE 4

ROS Class

&

Management 

Area Description

Designated 

Acreage

Urban

Gecko

Buttercup

Indicates that the area is characterized by a substantially urbanized 

environment, although the background may have natural-appearing 

elements. Renewable resource modification and utilization practices are 

often used to enhance specific recreation activities. Vegetative cover is 

often exotic and manicured, and sights and sounds from humans are 

predominant onsite. Large numbers of users can be expected both onsite 

and in nearby areas. Facilities for highly intensified motor use and parking 

are available with forms of mass transit often available to carry people 

throughout the site. 

29,067

Rural

Glamis

Ogilby

Dune Buggy

Indicates that the area is characterized by a natural environment that has 

been modified substantially by development of structures, vegetative 

manipulation, or pastoral agricultural development. Resource modification 

and utilization practices may be used to enhance specific recreational 

activities and maintain vegetative cover and soil. Sights and sounds of 

humans are readily evident, and the interaction among users is often 

moderate to high. Many facilities are designed for use by a large number of 

people, and facilities often are provided for special activities. Moderate 

user densities are present away from developed sites. Facilities for 

intensified motorized use and parking are available.

62,409

Roaded Natural

Mammoth Wash

AMA

Indicates that the area is characterized by a predominantly naturalappearing environment with moderate evidence of the sights and sounds of 

humans. Such evidence usually harmonizes with the natural environment. 

Interaction among users may be moderate to high, with evidence of other 

users prevalent. Resource modification and utilization practices are evident, 

but harmonize with the natural environment. Conventional motorized use is 

allowed and incorporated into construction standards and design of 

facilities.

41,394

Semi-Primitive 

Non-Motorized

North Algodones 

Dunes 

Wilderness

Indicates that the area is characterized by a predominantly natural or 

natural-appearing environment of moderate to large size. Interaction among 

users is low, but there is often evidence of other users. The area is managed 

in such a way that minimum onsite controls and restrictions may be present, 

but would be subtle. Motorized recreation use is not permitted, but local 

roads used for other resource management activities may be present on a 

limited basis.

26,202

Total 159,072

Under Alternative 4, management actions would be applied to ensure that the recreation 

experience at ISDRA is consistent with the ROS class designated to each of the eight 

management areas. In contrast, visitation under the baseline condition would continue to 

grow unmanaged. Compared to Alternatives 2 and 3, this alternative would provide an 

increased area available for rural and urban recreation experiences. Relative to Alternative 2 
246

and 3, Alternative 4 would provide less acreage designated to semi-primitive motorized 

recreational activity.

Management actions to be applied under Alternative 4 in support of the ROS designations 

include facility development and actions to ensure that the visitor supply (discussed below) at 

ISDRA is not substantially exceeded. The anticipated result is the conservation of recreation 

opportunities characterized by the urban, rural, roaded natural, semi-primitive motorized and 

semi-primitive non-motorized ROS classes. This alternative most closely meets the current 

and historical recreational activities and this is considered beneficial. Through the public 

scoping process, the BLM has documented that OHV enthusiasts want to keep the area the 

way it is managed under the 1987 RAMP, with increased enforcement and visitor services.

Visitor Supply

The estimated visitor supply at ISDRA under this alternative would be greater than that 

available under Alternatives 2 and 3. Please see Table 4.1-7. This is due to the increased 

acreage designated under urban, rural, and roaded natural.

TABLE 4.1-7 VISITOR SUPPLY BY MANAGEMENT AREA 

Area

DESIGNATED

ROS CLASS Visitor Supply A

Gecko Management Area Urban 50,921

Buttercup Management Area Urban 32,659

Mammoth Wash Management Area Roaded Natural 9,431

Glamis Management Area Rural 76,129

Ogilby Management Area Rural 58,174

Dune Buggy Flats Management Area Rural 46,759

North Algodones Dunes Management Area Semi-Primitive 

Non-Motorized

74

Total NA 274,147

aThe visitor supply presented is based on the acreage available for camping, the number of 

available campsites, an average number of vehicles per camping party, and an average 

number of people per vehicle.

Historically, visitation during major holiday weekends has often exceeded 100,000 visits 

(BLM, 2001q). While the total area available for OHV use under Alternative 4 would be 

similar to Alternative 2, the increased intensity (i.e., concentration of OHV users) is expected 

to increase available visitor supply by at least 20 percent over Alternative 2. Even so, the 

visitor supply under Alternative 4 may be exceeded on major holiday weekends. The annual 
247

supply is above the anticipated high range of future visits expected under Alternative 4 of 

approximately 1.8 million. Therefore, overall access at ISDRA could be maintained.

Other Management Actions

Impacts related to other management actions (e.g., facility development, nighttime closures, 

etc.) would be similar to those discussed previously under Alternative 2.

Other Resource Emphasis Areas Summary for all Alternatives

Land managed for other resource emphasis (i.e. natural and cultural resources) would also 

contribute to the spectrum of recreation settings and opportunities represented in the ISDRA. 

Generally, across all alternatives, lands allocated to other resource emphasis would favor 

types of recreation that involve fewer people and non-motorized activity. Areas where OHV 

recreation is restricted in the ISDRA would generally contribute to the semi-primitive nonmotorized setting, to the semi-primitive motorized setting, and to a small degree, the rural 

setting. An interpretive area, closed to motorized use, in the Buttercup Management Area, a 

rural ROS setting, is proposed in all of the action alternatives and would enhance natural and 

cultural conservation goals.

The larger areas emphasizing natural and cultural resource conservation would contribute to 

the semi-primitive non-motorized setting because other more developed settings are 

generally less compatible with natural and cultural resource objectives. Alternative 3 

proposes large areas of semi-primitive non-motorized in the ISDRA and the closure of 

Osborne Overlook to overnight camping for the development of an interpretive area. These 

areas would be closed to all motorized recreation and would have a substantial negative 

impact on the quality of OHV recreation in the ISDRA.

Alternative 4 proposes the implementation of an adaptive management area that will be 

classified as semi-primitive motorized and limited use by permit only for the protection of 

plant and animal species and their habitat. This area encompasses over 33,000 acres of the 

ISDRA and would reduce the level of open OHV recreation. Opportunities of OHV 

recreation would continue under a permit program and be limited to a controlled amount of 

vehicles. This would initially lead to the perception that a significant amount of opportunity 

has been lost. However, since the level of visitation in this area has been historically low to 

moderate (exact level of visitation to this area is not known, only estimated), and no more 

than 525 vehicles per day will be allowed in the area, it is possible that very few, if any 

visitors will be denied access to the area during the season. 

During the seasonal closure of the area for the protection of reptile species, there will be a 

significant level of OHV recreation opportunity lost. The time period of the seasonal closure 

coincides with the low visitation season in the dunes, therefore impacts to recreation would 

be reduced. 

Mitigation Measures

Under all action alternatives, there will be both a loss of available overnight camping space 

and a possible shift in visitation patterns due to the designation of the ROS classes and the 

inclusion of all areas into the fee area. These negative recreational impacts should be 

mitigated to minimize the effects on the recreating public. A proactive approach should be 
248

taken in order to control any future shift of visitation patterns in a manner that will benefit 

the public and the BLM.

The two new law enforcement “tools” discussed in the alternatives will have a negative 

impact on law breakers and law abiding visitors to the dunes. However, the public will also 

benefit by having a safer experience. These rules were developed to assist the Rangers in 

enforcing existing laws and bring the recreation area visitors into compliance with other State 

and Federal rules and regulation. The satisfaction of visitor experiences in the dunes, as well 

as management of visitor activities, needs to be closely monitored through surveys if these 

rules are to be used. Once both the visitors and management agree that the rules are no 

longer needed, they should be removed and not enforced.

Effects On Current Issues

Several of the issues, concerns, and opportunities identified by the public and BLM concern 

factors that degrade the quality of recreation experiences. The alternatives were designed to 

address several of the current issues and the implementation of them will have direct and 

indirect effects recreation.

Although many issues, concerns, and opportunities were identified in the public scoping 

process, the major concerns of the recreational visitors of the ISDRA are keeping the dunes 

open to OHV use, keeping the dunes open to vehicle camping, and keeping the dunes safe. 

All alternatives, except Alternative 1, the No Action Alternative, will reduce the amount of 

available open OHV area and camping. Although alternatives 2 and 4 would have the least 

amount of impact, they both limit the available area for OHV recreation and vehicle 

camping, and non-motorized camping. Alternative 3 would severely limit the amount of 

OHV opportunity. The concern is that these alternatives limit the open area for OHV 

recreation through the implementation of the adaptive management area. Closures, or 

limiting the existing open areas, will force OHV enthusiasts into smaller areas, which has 

already occurred in several areas throughout the California Desert. This increase in density 

of visitors in the dunes areas could not only degrade the OHV recreational experience, but 

also could affect the safety of the area. Keeping the dunes open under the 1987 RAMP 

conditions would allow the lowest density of visitors and the most area to disperse 

throughout the ISDRA. Hikers and equestrian visitors have rarely used the dunes. During the 

implementation of the temporary lawsuit closures, the BLM conducted a thorough 

monitoring program of the temporary closures. During this time the BLM was required to 

conduct aerial over flights and record intrusions into the closures. Over the two visitation 

seasons, the flight crew leads (Bower, FY01 and Himmerich, FY02) did not see any nonmotorized recreational use in the OHV closure areas. 

As discussed in earlier chapters, the dunes have experienced a number of unlawful visitors 

over the last several years. All alternatives, except Alternative 1, will address this issue 

through the enforcement of the current rules and regulations with a larger staff of law 

enforcement rangers. The possible implementation of the two proposed law enforcement 

tools regarding alcohol and curfews will help to address these concerns and will have both 

negative and positive impacts to the recreational experience, as discussed previously.
249

Cumulative Effects

The demands for OHV recreation in other areas are affected by actions taken in the ISDRA. 

The implementation of the Fee Demonstration Program, and the increased law enforcement 

in the Dunes has already started to spatially displace visitors throughout the desert. Through 

informal conversation with other OHV area managers, the El Centro Field Office has been 

advised that other areas are experiencing an increased level of visitors who used to come to 

the ISDRA. Some of these areas are Plaster City, Superstition Mountains, Ocotillo Wells, 

and Dumont Dunes Open Areas. 

As discussed in Chapter 3, OHV popularity in California continues to rise and legal 

opportunities for OHV recreation continues to decrease. At this time there is pending 

legislation that could possibly close another 2.5 million more acres as designated wilderness 

throughout California and other states (in addition to the 7,661,069 acres designated through 

the California Desert Protection Acts PL 103-433). There are areas within the El Centro 

Field Office area and the CDD that could be lost for any OHV opportunity. Also, several 

land use plans (listed below) around the desert could limit or close OHV open and limited 

areas within the CDD. These cumulative actions have been part of the cause of the dramatic 

increase of activity in the existing legal OHV open areas. California State Parks has 

documented an increase of 52% in the State Vehicle Recreation Areas between FY 86 and 

FY 00. Street licensed 4WD vehicle registrations in California have also increased 74% 

(290,651 to 506,585) between 1994 and 2001. Many of these street legal vehicles are used in 

the ISDRA and other OHV sites.

Land use plans that affect the cumulative impacts:

- Northern and Eastern Mojave Planning Effort

- Northern and Eastern Colorado Desert Coordinated Management Plan

- West Mojave Habitat Conservation Plan

- Western Colorado Route of Travel 

Cumulatively, these actions, and trends could cause some displacement of OHV activity from 

the ISDRA to other areas. It is unknown, and difficult to predict, where the visitation shift 

would occur. It is possible that the shift could occur into areas that currently require little 

recreational management or have a more sensitive habitat. The increased density of OHV 

recreation into the remaining legal areas would lead to a decrease in visitor satisfaction and 

public safety. As visitor density increases, the possibility of conflicts between visitors and 

the possibility of accidents increases. 
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4.2 Biological Resources

This section evaluates the project alternatives in terms of their potential impacts to biological 

resources. Biological resources are categorized as habitat types, special-status plants, and 

special-status and endemic wildlife as described in Chapter 3, Affected Environment. The 

Biological Assessment for the project also addresses specific impacts to, and mitigation for, 

the Peirson’s milk-vetch, desert tortoise, and flat-tailed horned lizard. 

Assumptions and Assessment Guidelines

Impacts to biological resources, as discussed in this section, are assumed to be adverse unless 

stated otherwise. The baseline conditions for this analysis are described as Alternative 1 (see 

Chapter 2). Analysis of the potential impacts focuses on changes in anticipated patterns of 

recreation use, both location and intensity that would result from implementing an 

alternative. 

Alternative 1 does not include the designation of management areas and ROS classifications 

as described for the action alternatives (Alternatives 2, 3 and 4). For Alternatives 2, 3, and 4, 

the eight management areas and one mile area around the ISDRA referred to as the planning 

boundary area as described in Chapter 2 will be collectively referred to as the Plan Area. The 

assessment of changes in the recreation use patterns of these three action alternatives is based 

on changes in ROS classifications as described in Section4.1, Recreation Resource. The 

ROS classifications designate the extent and nature of OHV activities that characterize a 

desired future condition associated with a particular alternative. Impacts considered in this 

chapter are then based on the extent to which the natural environment is likely to be modified 

by this level of activity, and thereby will serve as an index to potential changes in impacts to 

biological resources. The relative importance and sensitivity of biological resources in the 

vicinity of the proposed activities or development was factored into the impact analysis. 

For each of the alternatives, the three predominant habitat types (creosote bush scrub, 

psammophytic scrub, and microphyll woodland) within the ISDRA were considered. These 

habitat types would not be impacted by OHV recreation within the North Algodones Dunes 

Wilderness, which is closed to OHV use. Although canal-influenced vegetation is a fourth 

habitat type, it was not quantified for any of the alternatives because this habitat type is not 

anticipated to receive impacts as a consequence of OHV use. Such vegetation is on the 

margin of canals, in situations that are not suitable for OHV activity, and are consequently 

avoided by OHV users.

Impacts

Alternative 1

Under Alternative 1, the No Action Alternative, the ISDRA would continue to be managed 

based on the existing and approved management policies of the 1987 RAMP. Therefore, 

recreational facility development identified in the 1987 RAMP would be implemented. In 

addition, this alternative includes the designation of the North Algodones Dunes Wilderness 

Area, federal listing of the Peirson’s milk-vetch as a threatened species, and the release of 

Wilderness Study Area 362 from further studies. 
251

This alternative does not include the current interim OHV and camping closures. Also, there 

would be no revised biological monitoring or adaptive management program, new 

management areas would not be designated, and ROS classifications would not be assigned 

under this alternative.

Between 1985 and 2000, the number of visits at the ISDRA approximately tripled. This 

increase in visitor use represents an annual growth rate of approximately 7.5 percent during 

the period 1985 to 2000. In comparison, the State of California Department of Recreation has 

estimated growth in statewide OHV activity of approximately 3.5 percent annually. These 

two estimates represent the range of projected increases in visitation at the ISDRA under 

Alternative 1. 

Habitat Types

Potential impacts to habitat types including creosote bush scrub, psammophytic scrub, and 

microphyll woodland are expected to occur under Alternative 1. This is based on the 

description of Alternative 1 (see Chapter 2) that includes retaining OHV recreational 

activities in the entire ISDRA (with the exception of the North Algodones Dunes Wilderness 

Area), and based on the anticipated effects of increased visitor use over time. 

The estimated area of each of the three habitat types potentially impacted under Alternative 1 

is shown in the table below. The closure of the wilderness area to motorized vehicles has 

retained 26,202 BLM managed acres of habitat in an undisturbed setting. Approximately 

181,182 BLM managed acres could remain available to motorized recreational activities. 

(Please note that the acreage in the chart below does not “add up” to the number of acres of 

BLM managed land as the table below includes non-BLM managed land and the table below 

does not include other habitat types.)

Habitat Type Closed (Acres) Open (Acres) 

Creosote Bush Scrub 3,144 48,687

Psammophytic Scrub 15,983 91,702

Microphyll Woodland 7,075 57,831

The habitat fragmentation, soils compaction, and other potential impacts discussed below 

would not occur in the closed areas. Anticipated direct impacts to areas not closed to OHV 

recreational use would include loss, degradation, and fragmentation of habitat, particularly 

creosote bush scrub and psammophytic scrub. These impacts described below are not 

substantively different than the baseline conditions (see Chapter 3), and, therefore, the only 

marginal impacts would be those that would occur from increased visitor use. 

Under this alternative, facility development in accordance with the 1987 RAMP would still 

occur and is anticipated to contribute to potential impacts to habitat. This construction, 

however, is anticipated to occur in areas already heavily used for OHV recreation (as 

opposed to areas that contribute to maintaining habitat of the affected species). Therefore, 

impacts to habitat resulting from facility development are expected to be minimal. 
252

Indirect impact is anticipated as a result of the increased visitor use associated with facility 

expansion. This includes campground and access improvements resulting in increased use 

and in localized impacts to these habitat types. Indirect impacts include soil erosion and dust 

generation. Plants smothered by dust may experience reduced photosynthesis and 

transpiration, ultimately reducing vegetative cover. As desert environments are not generally 

conducive to rapid perennial plant growth (including regrowth), revegetation could take 

decades. Although the central deep sand dunes are not vulnerable to invasions of invasive 

species, reducing vegetative cover and disturbing soils as a result of recreational activities 

could increase the potential for such invasions. Invasive species in the eastern and western 

margins of the Plan Area, where underlying substrate is hard packed, may eventually 

displace some native vegetation. 

Special-Status Plants

Potential impacts to special-status plants are expected occur under Alternative 1. This 

assumes that the entire ISDRA, with the exception of the North Algodones Dunes Wilderness 

Area, would remain open to OHV recreational activities and projected visitor use would 

increase over time. Special-status plants that may be impacted from OHV and associated 

recreational development include: Peirson’s milk-vetch, Algodones dunes sunflower, 

Wiggins’ croton, giant Spanish needle, and sand food. Direct and indirect adverse impacts 

are anticipated to be similar to those described for the habitat types. Each of these species is 

dependent on psammophytic scrub habitat. Under Alternative 1, approximately 15 percent of 

this habitat type with be off limits to OHV use in the North Algodones Dunes Wilderness 

Area and 85 percent would be open to OHV use. 

Special-Status and Endemic Wildlife

As with habitat types and special-status plants, potential impacts to special-status and 

endemic wildlife are expected to occur under Alternative 1. This expectation is based on the 

assumption that the entire ISDRA, with the exception of the North Algodones Dunes 

Wilderness Area, will remain open to OHV recreational activities and the projected visitor 

use would increase over time. Primary impacts to special-status and endemic wildlife 

include direct mortality from recreational vehicles. Secondary impacts include destruction of 

forage and habitat; crushing of burrows; attraction of predators due to improper disposal of 

food and litter; harassment and illegal collection of wildlife; harassment by unleashed pets; 

dust, noise, lights associated with OHV and camping activities; and increased potential for 

invasion of non-native plants.

It has been shown that prolonged noise can adversely affect some lizards and small 

mammals. Investigations by Brattstrom and Bondello (1983) on the effect of OHV noise 

included the desert kangaroo rat (Dipodmys deserti), desert iguana (Dipsosaurus dorsalis), 

and Mohave fringe-toed lizard (Uma scoparia). Desert kangaroo rats and fringe-toed lizards 

demonstrated an immediate loss of hearing when exposed to OHV sounds of 95 dBA. 

Recovery of the kangaroo rat hearing took several weeks, during which time they would have 

been more vulnerable to predation. Effects are more likely where prolonged noise occurs. 

However, it is not known whether duration of vehicle noise levels anticipated at the ISDRA 

negatively impact wildlife. A single OHV can generate a noise level of 92 dB(A) at 50 feet, 

although the duration of the exposure is likely to be quite short as a vehicle passes by. 

Wildlife exposure to OHV noise is very localized and only at relatively high levels during the 

six holiday weekend during the year.
253

OHV activity tends to be concentrated within the psammophytic scrub. As a consequence, 

some special-status wildlife species such as the Colorado Desert fringe-toed lizard and 

endemic dune beetles occurring in these dunes would be killed or injured by OHV activity. 

Access routes through microphyll woodland habitat and open desert wash areas may result in 

direct impacts to the desert tortoise through running over tortoises or crushing burrows. 

These activities may also affect Couch's spadefoot toad habitat through disturbance of small 

ephemeral pools for which this species depends. The tendency for Couch's spadefoot toad to 

aggregate during breeding season may pose a higher risk from an increase in OHV activity in 

this area. 

For each of the alternatives potential impacts to Colorado Desert fringe-toed lizards and flattailed horned lizards were considered in detail. For the Colorado Desert fringe-toed lizard it 

is assumed that the all areas of psammophytic scrub and creosote bush scrub are occupied 

habitat. Under Alternative 1, approximately 19,127 acres, of habitat would be closed to 

motorized recreation in the North Algodones Dunes Wilderness while approximately 

140,389 acres of habitat would remain open to OHV use.

Alternative 2

There are two distinct differences in ROS classifications between Alternative 2 and both 

Alternatives 3 and 4. Under Alternative 2, the Glamis Management Area and Adaptive 

Management Area will be designated as roaded natural and semi-primitive motorized, 

respectively. The management focus for Alternative 2 would be a combined approach to 

accommodate continued use of the Plan Area for OHV recreational opportunities as well as 

protection of natural and cultural resources. The key component contributing to resource 

protection under Alternative 2 is the establishment of the Adaptive Management Area and 

implementation of an adaptive management program. Management of this area would 

include evaluating the effects of and revising management actions, as needed, to achieve a 

balance of providing a high quality recreation opportunities and conserving high value 

natural resources. Under Alternative 2, the visitor use is expected to increase from 3.5to 5 

percent annually relative to the low end estimated for the baseline. Additionally, the ROS 

classification of the Adaptive Management Area is expected to slightly increase overall 

OHV-related visitor use relative to the baseline. Therefore, this use is expected to be higher 

than under Alternative 3 (the area would be closed) but lower than Alternative 4. 

Habitat Types

Potential impacts to habitat types including creosote bush scrub, psammophitic scrub, and 

microphyll woodland are expected to decrease overall under Alternative 2, relative to 

Alternative 1. This conclusion is based on the designation of ROS classifications, 

implementation of an adaptive management strategy in the Adaptive Management Area, and 

projected annual visitor use increase differences. 

The area of each habitat type under Alternative 2 is shown in the table below. The Plan Area 

encompasses approximately 51,831 acres of creosote bush scrub, 107,685 acres of 

psammophytic scrub, and 64,906 acres of microphyll woodland totaling 224,422 acres of 

these three habitat types. These figures were used for the analysis of all action Alternatives. 

The North Algodones Dunes Wilderness Management Area would provide a total of 26,202 

BLM managed acres closed to motorized recreation. The Adaptive Management Area would 
254

provide a total of 33,289 BLM managed acres of controlled access. The Planning Area would 

provide a total of 48,312 BLM managed acres of limited use. These three areas total 107,803 

BLM managed acres that provide increased habitat protection through controlled access or 

use, or closure under Alternative 2. The remaining management areas open to OHV use total 

99,581 acres. Because the Plan Area encompasses an area of predominantly psammophytic 

scrub, this habitat type has the largest area amongst the habitat types. (Please note that the 

acreage in the chart below does not “add up” to the number of acres of BLM managed land 

as the table below includes non-BLM managed land and the table below does not include 

other habitat types.)

Habitat Type Closed To OHV Use 

(Acres)

Controlled Access 

(Acres)

 Open to OHV Use 

(Acres)

Creosote Bush 

Scrub

3,144 30,019 18,668

Psammophytic

Scrub

15,983 24,726 66,976

Microphyll 

Woodland

7,075 37,749 20,082

Moderate facility development, campground improvements, and road maintenance are 

anticipated under Alternative 2, and are expected to result in impacts to habitats similar to 

those described under Alternative 1. However, impacts to habitat within the Adaptive 

Management Area and the area that is encompassed by the Planning Area under Alternative 2 

are expected to substantially decrease relative to Alternative 1. Because OHV use would be

monitored and controlled within the Adaptive Management Area, only minor impacts to 

habitat are anticipated. Enforcement of the Adaptive Management Area and the limited use 

area surrounding ISDRA could include installing and maintaining signage. This could 

produce an edge effect along the boundaries, resulting in some loss of perennial vegetation. 

Concentrated recreational use is anticipated to continue within adjacent open areas, even 

within the camping areas, and may occasionally lead to unauthorized activity in closed or 

restricted areas. Creosote bush scrub and microphyll woodland, characterized by large 

upright woody plants with sharp branches, are generally avoided by OHV users. Therefore, 

OHV impacts would likely continue to be primarily within psammophytic scrub, which 

encompasses 107,685 acres.

Special-Status Plants

Impacts to special-status plants are expected to decrease under Alternative 2. This conclusion 

is based on adoption of an adaptive management approach, which entails monitoring specialstatus plants. Moderate facility development, campground improvements, and road 

maintenance are anticipated to result in impacts similar to those described under Alternative 

1. However, impacts to special-status plants within the Adaptive Management Area and 

Planning Area are expected to substantially decrease relative as a result of implementing 

conservation measures. Because OHV use would be controlled within the Adaptive 
255

Management Area, disturbance to special-status plants are anticipated on the newly

established boundary of the area. Enforcement of the Adaptive Management Area and the 

limited use area surrounding ISDRA could include installing and maintaining signage. 

Concentrated recreational use is anticipated within adjacent open areas, and at camping areas, 

and would result in the disturbance of special-status plants that may occur there. As 

previously stated, OHV use has been historically concentrated within psammophytic scrub. 

Therefore, OHV impacts are anticipated to be concentrated within this important habitat type 

for the five special-status plant species. For Alternative2, 40,709 acres of psammophytic 

scrub would receive protection either through closed OHV access in the North Algodones 

Dunes Wilderness or controlled access in the Adaptive Management Area.

Special-Status and Endemic Wildlife

Impacts to special-status and endemic wildlife are expected to decrease as a result of 

adopting adaptive management measures. Moderate facility development, campground 

improvements, and road maintenance are anticipated to result in impacts similar to those 

described under Alternative 1. However, impacts to special-status and endemic wildlife 

within the Adaptive Management Area and limited use area surrounding ISDRA are expected 

to substantially decrease. Because OHV use would be controlled within the Adaptive 

Management Area, negligible impacts to special-status and endemic wildlife are anticipated. 

Enforcement of the Adaptive Management Area and the limited use area surrounding ISDRA 

could produce an edge effect along the boundaries, resulting in loss or displacement of 

special-status and endemic wildlife there. Concentrated recreational use in the open areas 

may also result in the loss or displacement of special-status and endemic wildlife. 

Additionally, OHV activities, and therefore impacts, are anticipated to be concentrated within 

psammophytic scrub, which is an important habitat type for the Colorado Desert fringe-toed 

lizard. 

As for all alternatives, potential impacts to Colorado Desert fringe-toed lizards and flat-tailed 

horned lizards were considered in detail. For the Colorado Desert fringe-toed lizard it is 

assumed that the all areas of psammophytic scrub and creosote bush scrub are occupied 

habitat. Under Alternative 2, approximately 19,127 acres of habitat would be closed to 

motorized recreation in the North Algodones Dunes Wilderness, approximately 54,745 acres 

of habitat would be under controlled access within the Adaptive Management Area or limited 

access in the Planning Area; and approximately 85,644 acres of habitat in areas open to OHV 

use. 

Alternative 3

Under Alternative 3, the Plan Area would be managed under the same management area 

designations as Alternatives 2 and 4, but different ROS classifications would apply to those 

management areas. The management focus for this alternative would be protection of natural 

and cultural resources through the use of closures. Accordingly, Alternative 3 would 

designate the Mammoth Wash, and Adaptive Management Areas as semi-primitive nonmotorized. Management of these areas would be much the same as the North Algodones 

Dunes Wilderness Management Area in terms of natural resources protection resulting from 

the prohibition of OHV activities. It is expected that the one-mile perimeter area within the 

plan area would receive little use due to its location near the closed areas and its OHV 

limited use classification.
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Under Alternative 3, visitor use is expected to slightly increase from 3.5 to 4percent 

annually relative to the low end of the baseline. However, the ROS classifications of the 

Mammoth Wash and Adaptive Management Areas are expected to reduce overall OHVrelated visitor use in these areas. Therefore, this growth in visitor use is expected to be lower 

than either Alternatives 2 or 4 within these three management areas.

Habitat Types

Potential impacts to the three predominant habitat types are expected to decrease under 

Alternative 3 based on the projected modest increases in visitor use and on the impacts 

extrapolated from the ROS classifications previously described. 

As shown in the table below, the closure of three management areas to motorized vehicles 

and the anticipation that the one mile planning area would receive little use, would result in 

approximately 130,310 acres of the three habitat types being mainly undisturbed by OHV use 

in the future. This represents the combined total of the Mammoth Wash Management Area, 

North Algodones Dunes Wilderness Management Area, Adaptive Management Area, and 

Planning Area. This is by far the largest area of closure of any of the alternatives. The 

remaining management areas total of 94,112 acres would remain open to OHV use.

As the table shows, microphyll woodland is provided the greatest of protection from impacts 

from OHV use under Alternative 3 and compared to the other two habitat types under 

consideration. 

Habitat Type Closed to OHV use (Acres)

Open to

OHV use (Acres)

Creosote Bush Scrub 34,678 17,153

Psammophytic Scrub 47,705 59,980

Microphyll Woodland 47,927 16,979

Minor facility development, campground improvements, and road maintenance are 

anticipated to result in similar, but lesser impacts under Alternative 3 than under the other 

alternatives. The major difference between Alternative 3 and others is that no or negligible 

impacts to habitats from OHV use are anticipated within the Mammoth Wash, North 

Algodones Dunes Wilderness, Adaptive, and Planning Areas due to the closures. However, 

the anticipated edge effect, in the form of crushing of vegetation and soil disturbance along 

the closed boundaries of these areas, may be substantial relative to that under other 

alternatives. This may ultimately result in habitat loss along these boundaries. A substantial 

increase in the concentration of recreational activities in the areas that would remain open to 

OHV use may also result from a reduction in area available for OHV recreation. 

Unauthorized activities in the closed areas may also occur. As stated earlier, OHV use has 

historically been concentrated within psammophytic scrub. However, due to a reduction in 

area open to OHV recreation under this alternative, increased impact to creosote bush scrub 

and microphyll woodland are expected as recreational enthusiasts seek other areas to enjoy 

their sport. Nonetheless, these potential impacts are considered minor relative to the benefit 

of protecting habitat within the closed management areas.
257

Special-Status Plants

Based on the projected visitor use increases and ROS classifications; impacts to specialstatus plants are expected to decrease under Alternative 3 relative to the other alternatives. 

Minor facility development, campground improvements, and road maintenance are 

anticipated to result in similar, but lessened impacts relative to other alternatives. The major 

difference between Alternative 3 and other alternatives is that no OHV impacts to specialstatus plants are anticipated within the Mammoth Wash, Adaptive, and Planning Areas due to 

a non-motorized ROS classification of Mammoth Wash and the Adaptive Management 

Areas. However, the anticipated edge effect along the closed boundaries may ultimately 

result in loss of special-status plants along the boundaries. A substantial increase in the 

concentrated recreational use in the areas still open to OHV use may result in increased 

losses of special-status plants there. Additionally, OHV impacts are anticipated to be 

concentrated within psammophytic scrub, which is an important habitat type for the five 

special-status plants. A major feature of the effects of the enactment of this alternative would 

be that approximately 47,705 acres of psammophytic scrub, or 44 percent of the total habitat 

type within the ISDRA, would not be greatly impacted due to OHV use. 

Special-Status and Endemic Wildlife

Based on the projected visitor use increase and ROS classifications, impacts to special-status 

and endemic wildlife are expected to decrease under Alternative 3. Minor facility 

development, campground improvements, and road maintenance are anticipated to result in 

similar, but lessened, impacts relative to the baseline. The major difference between 

Alternative 3 and others is that no impacts to special-status and endemic wildlife resulting 

from OHV use are anticipated within the Mammoth Wash, North Algodones Dunes 

Wilderness, Adaptive, and Planning Areas due to the closures of the three management areas. 

However, the anticipated edge effect along the closed boundaries may be substantial. This 

may ultimately result in loss or displacement of special-status and endemic wildlife along the 

boundaries. A substantial increase in the concentrated recreational use in the open areas may 

result in increased impacts to special-status and endemic wildlife. Additionally, OHV 

impacts are anticipated to be concentrated within psammophytic scrub, which is an important 

habitat type for the Colorado Desert fringe-toed lizard. Nonetheless, these potential impacts 

are considered minor relative to the benefit of protecting these species within the closed 

management areas.

Potential impacts to Colorado Desert fringe-toed lizards and flat-tailed horned lizards were 

again considered in detail. For the Colorado Desert fringe-toed lizard it is assumed that the 

all areas of psammophytic scrub and creosote bush scrub are occupied habitat. Under 

Alternative 3, approximately 82,383 acres or 52 percent of habitat would not be impacted due 

to motorized recreation; and approximately 77,133 acres of habitat, or 48 percent in areas 

open 

Alternative 4

Under Alternative 4, the Plan Area would be managed under the same management areas 

Alternatives 2 and 3 but different ROS classifications. There are two differences in ROS 

classifications between Alternative 4 and the other alternatives. Under Alternative 4, the 

Adaptive Management Area and Mammoth Wash Management area would be designated 
258

roaded natural. These two management areas encompass a total of approximately 41,394 

BLM managed acres, or 20 percent of the BLM managed Plan Area.

Glamis Management Area, Dune Buggy Flats Management Area, and Ogilby Management 

Area would be designated as rural. These three areas encompass a total of approximately 

62,408 acres or 30 percent of the BLM managed Plan Area. The Gecko Management Area 

and Buttercup Management Area would be designated as Urban. These two areas 

encompasses 29,067 acres, or 14 percent of the BLM managed Plan Area

The change in ROS classifications under Alternative 4 would result in substantially increased 

OHV recreational opportunities. The change would also effectively result in implementation 

of a desired future condition that would accommodate a shift in visitor use from lowmoderate under the other alternatives to moderate-high under Alternative 4. The management 

focus for this alternative would be providing additional facilities to accommodate increased 

visitation, including new campgrounds, camping, toilets, trash stations, and information 

kiosks. Under Alternative 4, the visitor use is expected to increase from 3.5 to 6percent 

annually relative to the low end of the baseline. Additionally, revising the ROS 

classifications of the Adaptive Management Area and Glamis Management Area is expected 

to increase overall OHV-related visitor use. Therefore, this growth rate is expected to be the 

highest relative to Alternatives 2 and 3.

Habitat Types

Based on the projected visitor use increases and previously described ROS classifications, 

potential impacts to habitats are expected to increase under Alternative 4. 

The area of each habitat type under Alternative 4 is shown in the table below. As shown in 

this table, the continued closure of the North Algodones Dunes Wilderness Management 

Area would result in retaining 26,202 BLM managed acres of habitat in an undisturbed 

setting. The Adaptive Management Area would provide an additional total of 33,289 BLM 

managed acres of controlled vehicle access, however, this areas designation as road natural 

would likely result in increase motorized use and thereby increase impacts. The Planning 

Area would provide a total of 48,312 acres of controlled use. These three areas total 107,803 

BLM managed acres that are managed on controlled OHV use. The remaining management 

areas total 99,581 BLM managed acres and would be open to OHV use. (Please note that the 

acreage in the chart below does not “add up” to the number of acres of BLM managed land 

as the table below includes non-BLM managed land and the table below does not include 

other habitat types.)

Habitat Type Closed (Acres)

Controlled Access 

(Acres) Open (Acres)

Creosote Bush Scrub 3,144 30,019 18,668

Psammophytic Scrub 15,983 24,726 66,976

Microphyll Woodland 7,075 37,749 20,082
259

Substantially increased facility development, campground improvements, and road 

maintenance are anticipated to result in increased impacts to habitats as a result of increased 

OHV activity. With the ROS designation of the Glamis Management Area as rural and 

Adaptive Management Area as roaded natural, impacts to habitat are also anticipated to 

increase in these management areas as a result of increased recreation. Thus, under this 

alternative, the greatest difference is the potential increase in impacts to habitats within the 

Glamis and Adaptive Management Areas. Although the table illustrates the total area of 

habitat under controlled access as 92,494 acres, impacts to habitat within the Adaptive 

Management Area are anticipated to be higher than for the other alternatives because it is 

expected that this area would receive increased use under this alternative. Microphyll 

woodland is provided the greatest percentage of closure within the Plan Area. 15 percent or 

less of each habitat type within the Plan Area are closed under Alternative 4. 

Special-Status Plants

Based on the projected annual growth rate increase and ROS classifications, potential 

impacts to special-status plants are expected to increase under Alternative 4. Increased 

facility development, campground improvements, and road maintenance are anticipated to 

result in increased OHV use in the Plan Area, and therefore increased impacts to specialstatus plants. With the ROS designation of the Glamis Management Area as rural and the

Adaptive Management Area as roaded natural, impacts to special-status plants are anticipated 

to increase in these management areas as OHV activity increases. Under this Alternative 

only the 15,983 acres of psammophytic scrub within the North Algodones Dunes Wilderness 

Area would be the only area supporting the special status plant species that would not 

experience increased OHV use.

Special-Status and Endemic Wildlife

Based on the projected annual growth rate increase and ROS classifications, impacts to 

special-status and endemic wildlife are expected to increase for Alternative 4. Additionally, 

increased facility development, campground improvements, and road maintenance are 

anticipated to result in increased OHV activity and, therefore, impacts to special-status and 

endemic wildlife. With the ROS designation of the Glamis Management Area as rural and 

the Adaptive Management Area as roaded natural, impacts to special-status and endemic 

wildlife are anticipated to increase in these management areas as level of OHV activity 

increases.

As for all alternatives, potential impacts to Colorado Desert fringe-toed lizards and flat-tailed 

horned lizards were considered in detail. For the Colorado Desert fringe-toed lizard it is 

assumed that the all areas of psammophytic scrub and creosote bush scrub are occupied 

habitat. Under Alternative 2, approximately 19,127 acres, or 13 percent, of habitat would be 

closed to motorized recreation in the North Algodones Dunes Wilderness, approximately 

54,745 acres of habitat would be under controlled access within the Adaptive Management 

Area or limited access within the Planning Area; and approximately 85,644 acres of habitat 

in areas open to OHV use.

Mitigation Measures

No additional mitigation measures are required beyond those management actions 

incorporated into the action alternatives.
260

Cumulative Effects

Land use plans that affect the cumulative impacts:

- Northern and Eastern Mojave Planning Effort

- Northern and Eastern Colorado Desert Coordinated Management Plan

- West Mojave Habitat Conservation Plan

- Western Colorado Desert Route of Travel Plan

Cumulatively, these actions, and trends could cause the displacement of OHV activity from 

the ISDRA to other areas or from other areas to the ISDRA. It is unknown, and difficult to 

predict, where the visitation shift would occur. It is possible that the shift could occur into 

areas that currently require little recreational management or have a more sensitive habitat. 

This could have a negative impact on species and their habitat, although each of these plans 

was developed with an emphasis on species and habitat conservation. 

The United States Border Patrol frequently utilizes the project area, and other desert areas 

near the project area for surveillance and apprehension of undocumented immigrants. These 

activities result in surface disturbance, and some habitat and species loss.

The Salton Sea Restoration Plan, the Coachella Valley Water Management Plan and the IID 

Water Conservation and Transfer Project and Habitat Conservation Plan each have the 

potential of surface disturbance, and some habitat and species loss.

The North Baja Pipeline Project is nearly complete. This project had some surface 

disturbance, loss of habitat and species.

The Mesquite Mine has created some loss of habitat to the desert tortoise. The mine has a 

program to physically relocate tortoise that may be impacted by the mining operations to a 

different location.
261

4.3 Law Enforcement and Public Safety

The mission of the BLM is “to sustain the health, diversity, and productivity of the public 

lands for the use and enjoyment of present and future generations” (BLM, 2002). This 

section assesses impacts to law enforcement and public safety as a result of implementing the 

alternatives presented in Chapter 2 of this EIS.

Impacts Common To All Alternatives

The majority of visitors to the ISDRA are seeking a recreational experience that is consistent 

with activities that conform to existing laws and public safety. Other visitors, however, are 

seeking a recreational experience that is unlawful or contributes to threats to public safety. 

Most of these instances of unlawful behavior occur during the six major holiday weekends 

during the high-use season (i.e., Halloween, Thanksgiving, New Year’s, Martin Luther King 

Day, President’s Day, and Easter). During these weekends, illegal behavior increases with 

the increased visitor use.

 

The objective of all the alternatives assessed in this EIS is to provide law enforcement staff, 

associated equipment, and facilities sufficient to promote public safety and to curtail illegal 

behavior, thus providing enhanced opportunities for visitors seeking recreational experiences 

that comply with public safety and are conducted in accordance with pertinent laws. All the 

alternatives, including the No Action, are anticipated to improve public safety compared with 

the existing baseline conditions. 

For all alternatives, the need for additional law enforcement staff would occur mostly during 

the six major holiday weekends. Temporary law enforcement staff would continue to be 

used to encourage public safety during the high visitor use weekends. 

Under all the alternatives, visitor use is anticipated to increase over time as a result of 

continuing popularity of the dunes and limitations on other OHV recreational opportunities in 

the CDCA Plan Area.

Impacts Common To The Action Alternatives 

For the action alternatives (Alternatives 2, 3, and 4), the use of temporary law enforcement 

officers would continue; and additional permanent staff would be hired. 

Other measures for the action alternatives would include a new management tool that could 

be utilized on an as needed basis. The management tool would be utilized temporarily, as 

required to maintain law and order, when other more traditional law enforcement tools have 

not curtailed the lawless behavior at specific locations. It is expected that this tool would be 

utilized on an infrequent basis. This tool is the temporary closures of specific areas such as 

Competition Hill (North and South), Oldsmobile Hill, Test Hill, Patton Valley, the sand 

drags, and other areas as needed. The time that the closure begins and ends would be 

announced by law enforcement every time the temporary closure tool is utilized. Visitor use 
262

and incident data will be monitored and used to evaluate the need for this tool and to develop 

the criteria for its use. 

The action alternatives also include another tool that can be used as needed. This tool is a 

ban on alcohol use outside designated camping areas. The time that the ban begins and ends 

would be announced by law enforcement every time the temporary alcohol ban tool is 

utilized. Visitor use and incident data will be monitored and used to evaluate the need for 

this tool and to develop the criteria for its use. Members of the American Sand Association, 

BLM, Imperial County Sheriff’s Office and others will jointly address safety problems with 

the sand drags at Gecko Road and Dune Buggy flats. Speed and reckless driving laws for 

vehicles traveling within 50’ of the crowd will be strictly enforced by the use of radar guns 

and existing enforcement efforts. In addition, a strong public education campaign will be 

implemented. Better posting and enforcement of speed limits, and a zero tolerance policy for 

holiday weekends will continue. 

Overall, it is anticipated that implementing the management actions above would deter 

visitation by users who engage in the unlawful and/or dangerous activities. This initial 

decrease in visitor use, however, would be offset by management actions intended to 

improve the overall quality of the recreational experience at ISDRA. It is anticipated that 

new and improved facilities, improved public safety measures, public information 

encouraging off-peak visits, and other measures would attract visitors seeking OHV 

recreation experiences consistent with legal activities. 

Under the action alternatives (Alternatives 2, 3, and 4), public safety is expected to improve 

compared with baseline conditions because of the proposed increases in permanent law 

enforcement staff and the additional management measures (e.g., restrictions on alcohol 

consumption, posting speed limits).

Impacts

Alternative 1

Under Alternative 1, the objective to encourage public safety would be accomplished by 

continued use of permanent and temporary law enforcement staff at the popular high-use 

areas. Law enforcement activities in the ISDRA would continue in accordance with 

measures specified in the 1987 RAMP. Development of facilities to support law 

enforcement (e.g., new ranger stations and increases to personnel and associated equipment) 

would occur only to the extent directed by the 1987 plan. Law enforcement staff will 

continue to be provided on the six major holiday weekends in numbers sufficient to 

encourage public safety, and the existing staffing measures would remain in effect. 

These conditions would be comparable to the baseline conditions and, therefore, would not 

contribute to a decrease in conditions of public safety at the ISDRA. The BLM would 

continue to commit to providing adequate law enforcement staff and would continue to rely 

on neighboring jurisdictions to provide temporary staff commensurate to meet the anticipated 

visitor use.
263

Alternative 2

Under Alternative 2, public safety would be improved through the use of a new ranger station 

at Cahuilla and a permanent ranger station at Buttercup. These stations will allow for the onsite detention of violators and for improved communication between the officers working 

throughout the ISDRA. It is expected that public safety would increase and lawless behavior 

would decrease due to the permanent presence of law enforcement at these locations and 

increased law enforcement staffing and better interagency coordination.

Alternative 3

Under Alternative 3, public safety would be improved through the use of a new ranger station 

at Osborne Outlook and a permanent ranger station at Buttercup. These stations will allow 

for the on-site detention of violators and for improved communication between the officers 

working throughout the ISDRA. It is expected that public safety would increase and lawless 

behavior would decrease due to the permanent presence of law enforcement at these 

locations and due to the reduction in the number of visitors under this alternative. 

Alternative 4

Under Alternative 4, public safety would be improved through the use of new ranger stations 

at Cahuilla and Buttercup. These stations will allow for the on-site detention of violators and 

for improved communication between the officers working throughout the ISDRA. It is 

expected that public safety would increase and lawless behavior would decrease due to the 

permanent presence of law enforcement at these locations, due to the increase in law 

enforcement staffing and better interagency coordination. However, this may be off set due 

to the increase in the total number of visitors under this alternative.
264

4.4 Social

Effects Common to All Alternatives 

The social impacts are described in terms of effects to social well being for all alternatives. 

The types of things that could affect social well being includes the types and the quantities of 

the recreational experience that is available. It also includes the perception of conflict 

concerning resource use and an individual’s sense of control over decisions relating to their 

experience. Other beliefs that could affect a person’s social well being includes an 

individual’s sense of control over their future and their sense of job security.

No alternative would affect the demographics included in the affected environment. The 

affects on major social trends included in the affected environment would be expected to be 

the same for all alternatives. However, the projected growth rate of the recreational use may 

be somewhat lower than in the past for all alternatives due to the perception that there may be 

less recreational opportunities in the future. This perception could result in a delay or 

hesitation to make major purchases for OHV use. However, according to Taking the High 

Road, OHV purchases are increasing as OHV opportunities are decreasing.

Impacts

This section will include a discussion of the affect that each alternative could have on the 

various groups identified in Section 3.4 as affected groups.

Alternative 1

Affects to all groups would continue as they have in the past. This alternative is most 

responsive to the non-local OHV related business owners, the economics of the local 

communities and the vendors. This alternative is most responsive to the desires of groups 

and individuals who would like the number of visitors to the ISDRA to remain uncontrolled. 

The OHV recreational users would partially support this alternative. Although the 

unrestricted visitor use would provide a sense of well being, this could be off set by the 

uneasiness over the lack of increased law enforcement.

Environmental advocacy groups do not support this alternative, as they believe that the 

current management does not provide sufficient protection to natural resources. The 

condition of natural resources on public land is important to these groups as they place value 

in wildlife, plant species, wilderness and solitude.

The vendors would support this alternative since it allows them to continue to operate as they 

have in the past. The vendors would have an increased sense of well being, as they are more 

comfortable with the current conditions.

The OHV related businesses would partially support this alternative, as it does not place a 

restriction on the number of visitors that recreate at the ISDRA. This could increase their 
265

sense of well being, due to a perception of job security. However, local community business 

owners may not support this alternative, as it does not address the competition between the 

vendors and the local businesses on land that is privately owned adjacent to the ISDRA. It 

also does not improve the vendors’ compliance with federal vending regulations. The local 

land owning businesses may have less of a sense of well being due to their perceived unfair 

competition with the vendors. 

The local community would partially support this alternative from an economic viewpoint, 

but not from a law enforcement viewpoint. The local community desires increased law 

enforcement, which would not be consistent with this alternative. Many members of the 

local community involved in some retail and service businesses would desire this alternative, 

as it does not place a restriction on the number of visitors that recreate at the ISDRA. Other 

local community business owners would not support this alternative, as it does not address 

the competition between the local businesses and the vendors. Some members of the local 

community would have an increased sense of well being due to a perception of job security, 

whereas others would have a decreased sense of well being due to the competition from 

vendors. Members of the community that are concerned with lawlessness at ISDRA would 

have a decreased sense of well being. 

This alternative would allow the continued conflict between the vendors and local 

businesses. It also would not address the growing conflict between the OHV recreational 

users and the environmental advocacy groups. 

Alternative 2

This alternative is a middle ground between the OHV recreational users and the 

environmental advocacy groups desired management of the ISDRA. Although neither of 

these groups will be fully satisfied with this alternative, both groups will also have a lot of 

their basic desires met. The OHV recreational users may have a sense of well being from 

this alternative because they will be able to recreate in all the areas that they historically 

utilized. They will not be completely satisfied as there is a permit system that is required for 

one area that has historically been a low use area and there is the potential of visitor supply 

restrictions in the future. The environmental advocacy groups may also have somewhat of a 

sense of well being from this alternative as the resources that they value will be conserved, 

although they will not be entirely satisfied with this alternative because the recreational use 

that is allowed is more than the environmental advocacy groups desire. This alternative is 

most responsive to the desires of groups and individuals who would like a balanced use of 

the ISDRA. 

The vendors would not fully support this alternative since it requires that a popular vending 

area that is in direct competition with an adjacent private land owned business become a 

short term vending area. This will reduce competition with the local businesses and bring the 

vending program closer to the federal vending requirements. Currently most vendors are 

short term vendors, but a few vendors are long term, staying at their vending location 

throughout the duning season. Long term vending is allowed at a specific location that will 

have less direct effect on the locally owned businesses. The development of three short term 

vending areas will restrict the vendors ability to vend and live at the ISDRA full time. The 
266

vendors would have a decreased sense of well being, due to concerns about future 

employment security and residential concerns.

The OHV related businesses would likely support this alternative, as it does not place a great 

restriction on the number of visitors that recreate at the ISDRA and it would reduce 

competition between the vendors and local businesses. This alternative could increase their 

sense of well being, due to a perception of job security.

The local community would likely support this alternative from an economic viewpoint, and 

from a law enforcement viewpoint. The local community desires increased law enforcement, 

which would be consistent with this alternative. Many members of the local community 

involved in some retail and service businesses would desire this alternative, as it does not 

place a great restriction on the number of visitors that recreate at the ISDRA. The local 

community also believes that visitation limits will have a negative effect on the community. 

Local community business owners would support this alternative as it places some 

restrictions on the vendors to bring them into compliance with federal regulation. However, 

there would still be more competition between vendors and the local businesses than the local 

businesses would like, as the local businesses would prefer that vending be restricted to 

holiday weekends. Members of the local community would have an increased sense of well 

being due to a perception of job security, less competition from vendors and increased law 

enforcement. 

This alternative would partially address the conflict between the vendors and local 

businesses. It also would at least partially address the growing conflict between the OHV 

recreational users and the environmental advocacy groups.

Alternative 3

This alternative is most responsive to the environmental advocacy groups. This alternative is 

most responsive to the desires of groups and individuals who would like to decrease the 

number of visitors to the ISDRA, to greatly limit the OHV recreational use, and increase 

resource conservation. 

The OHV recreational users would not support this alternative. The restricted visitor use 

would provide a sense of uneasiness. They would not be able to recreate at the ISDRA in the 

same numbers and ways as in the past. They would believe that their recreational 

opportunity at ISDRA was unfairly taken away.

The vendors would not support this alternative since it would severely limit the visitors to the 

ISDRA and they would not be able to continue to operate as they have in the past. The 

vendors would have a decreased sense of well being, as they would have fewer opportunities 

to vend due to the reduction in potential customers.

The OHV related businesses would not support this alternative, as it places a severe 

restriction on the number of visitors that recreate at the ISDRA. This could decrease their 

sense of well being, due to a perception of a lack of job security. 
267

The local community would not support this alternative from an economic viewpoint, but 

would support it from a law enforcement viewpoint. The local community desires increased 

law enforcement, which would be consistent with this alternative. Many members of the 

local community involved in some retail and service businesses would not desire this 

alternative, as it does places a severe restriction on the number of visitors that recreate at the 

ISDRA. Some members of the local community would have a decreased sense of well being 

due to a perception of a lack of job security, whereas others would have an increased sense of 

well being due to reduction in lawlessness. 

This alternative would increase the continued conflict between the vendors and local 

businesses, as the number of potential customers would decrease. It also would not address 

the growing conflict between the OHV recreational users and the environmental advocacy 

groups since the OHV users would feel that they were not provided with a fair amount of 

recreational opportunities.

Alternative 4

This alternative is most responsive to the OHV recreational users, the OHV related business 

owners, the local communities and the vendors. This alternative is most responsive to the 

desires of groups and individuals who would like the number of visitors to the ISDRA to 

remain the same or increase and who are less concerned about resource conservation. Since 

the recreational opportunities would be greatest under this alternative, these groups would 

gain a sense of well being as they would be able to recreate and have a perception of job 

security. Some members of the local community may be concerned about the potential for an 

increase of lawlessness. This could create a sense of uneasiness. 

Environmental advocacy groups would not support this alternative, as they believe that it 

does not provide sufficient protection to natural resources. The condition of natural 

resources on public land is important to these groups as they place value in wildlife, plant 

species, wilderness and solitude. Implementation of this alternative would create a feeling of 

uneasiness for members of these groups.

This alternative may possibly reduce the continued conflict between the vendors and local 

businesses since the customer base may expand, although the vendors would remain in direct 

competition with the local businesses. It also would not address the growing conflict 

between the OHV recreational users and the environmental advocacy groups. This conflict 

would escalate, as the environmental advocacy groups would believe that this alternative did 

not fairly address their concerns.

Mitigation

No mitigation is required, although the vendor program should be monitored and possibly 

adjusted to minimize impact on the local businesses.
268

Cumulative Effects

None identified.
269

 4.5 Economic

This section presents the economic impacts of implementing the alternatives presented in 

Chapter 2. 

 

Assumptions and Assessment Guidelines

Regional economic impacts of recreation are typically assessed on the basis of visitor trip 

expenditures. The money spent by visitors on food, lodging, and transportation is the input 

into the local economy. Management alternatives that affect the amount or type of money 

spent would affect the local economy. 

Estimates of total trip expenditures were developed from data on the number of visits to the 

ISDRA under each of the management alternatives in combination with trip-related 

expenditures based on a 1993 study developed by the OHV Division of the California 

Department of Parks and Recreation (California Parks and Recreation, 1997). 

Trip-related expenditures (e.g., food, lodging, transportation, and activities) are typically 

divided into three groups: those made at or near home, those made en route to and from the 

recreation site, and those made at or near the recreation site. Only expenditures made by 

nonresidents were used in determining economic impacts. Although expenditures by local 

residents could support recreation related businesses, these expenditures were not included in 

the economic impact analysis. These expenditures that were analyzed would include all 

expenditures made at or near the site as well as a portion of the expenditures made en route.

For this analysis, the following assumptions were made:

The major regions of influence that are included in the economic impact analysis are 

Imperial County, California, and Yuma County, Arizona. The actual amount of 

money spent outside of these areas is large, however, the potential impacts to 

Imperial County and Yuma County would be more noticeable as these counties have 

existing high unemployment rates and a less diverse economic base. Although many 

businesses that specialize in OHV related equipment and supplies that are located 

outside this area could be significantly impacted on an individual basis, this impact 

would have less effect on the overall economics of the region in which the business is 

located because these areas generally have healthy economic bases. Businesses that 

provide equipment and supplies are located throughout the United States. 

Ninety percent of the visitors to ISDRA are nonresidents of Imperial County.

Of the total nonresident visitors, 86 percent are from other parts of California while 

the remaining 14 percent are from Arizona.

Arizona residents spend approximately 60 percent of their trip expenditures at home. 

Of the remaining 40 percent, 30 percent is spent in Yuma and 10 percent in 

Imperial County.
270

A visit to the ISDRA represents a 3-day (2-night) stay.

Because mean trip expenditures are on a per-household basis and visitation data are 

on a per-person basis, household trip expenditures are divided by three 

(approximately the number of persons per household or the number of persons per 

family in California (DOF, 2001)).

Trip expenditures are analyzed the same for OHV and non-OHV visitors. The 10% 

of visitors that stated they recreated at the dunes for reasons other than OHVs 

included people who came to the ISDRA to be with friends and family, etc. It is 

assumed that these individuals came to the dunes with OHV recreational enthusiasts 

and their expenditures would be similar to and intermixed with the OHV enthusiast’s 

expenditures. Although those who recreate at the dunes by hiking and backpacking 

would be expected have less expenditures, this is believed to be a minor number of 

individuals, so their expenditures were not calculated separately. 

All fees collected by BLM, after the cost of collection, stay within Imperial County. 

(The contractor that collects the fees is based in San Diego.)

The base year of analysis is 1998 for Imperial County and 1997 for Yuma County, 

but the impacts were adjusted to reflect year 2000 price levels. 

Alternative 1 is the same as the baseline condition for comparative analysis.

Although an initial decrease in visitor use could occur for all the action alternatives 

(Alternatives 2, 3, and 4), the demand for recreational opportunities at the ISDRA is 

anticipated to increase; and visitor use is expected to increase commensurately as a 

result of decreasing OHV recreational opportunities at other desert Southwest sites.

For purposes of this analysis, an alternative would have an adverse impact on the economy if 

it would:

Cause a temporary or permanent reduction in employment that is substantial (greater 

than 5 percent) in relation to the existing employment levels

Result in a decline in total local earnings in the area by 5 percent or more

Compliance with NEPA:

In Morris v. Meyers the courts determined that “NEPA was not intended to provide a 

process for addressing social and economic shortcomings in our society, but to ensure 

that agencies consider the consequences of their actions on the land, air, water, and 

other natural resources upon which society depends. Social and economic 

consequences of agency action may be considered under NEPA only if they are 

caused by damage to the physical environment.”
271

During the public comment period for the draft EIS, many commentors requested that 

BLM conduct an extensive study on the social economics of OHV use at the ISDRA. 

BLM has not conducted a study on the social economics of OHV use at the ISDRA 

for this EIS as it is outside the scope of the project. This type of study is also not 

required under NEPA for this project, as any social economic shortcomings would 

not be caused by damage to the physical environment. However, the social and 

economic issues are more thoroughly addressed in the final EIS than in the draft EIS.

Data

Two data sources were used to derive the total trip expenditures by expenditure category. 

Total number of visits per year to the ISDRA under each alternative was developed from 

available survey data. A “trip” equates to a 3-day stay at the Dunes and is assumed to be 

equivalent to the number of visits provided in Table 4.1-1. Trip expenditure data came from 

the California Department of Parks and Recreation’s Off-Highway Vehicle study. 

Table 4.5-1 shows the total number of trips under baseline condition and each of the 

alternatives, while Table 4.5-2 shows the household trip expenditures by expenditure type. 

Table 4.5-1 Estimated Visitor Use and Origination

Nonresident 

Householdsb

Alternatives

Estimated 

Number of 

Visits

Number of 

Householdsa

Resident 

(Imperial) 

Households Californiac Arizonad

Baseline Condition 867,753 289,251 28,925 223,880 36,446

All Alternatives – 2002-

2003 

1,005,000 335,000 301,500 259,290 42,210

2012-2013 Season: Low 

Estimate

 Alternatives 1, 2, 3 and 

4

1,418,000 472,667 425,400 365,844 59,556

2012-2013 Season: High 

Estimate 

 Alternative 1 2,071,000 690,333 621,300 534,318 86,982

 Alternative 2 1,637,000 545,667 491,100 422,346 68,754

 Alternative 3 1,488,000 496,000 446,400 383,904 62,496

 Alternative 4 1,800,000 600,000 540,000 464,400 75,600

Source: BLM, 2001

a Based on the assumption of three persons per household

b

 Households that are not residents of Imperial County (90% of households)

c

 California households outside Imperial County (86% of nonresident households)

d

 Arizona households account for 14% of nonresident households visiting ISDRA and spend 

about 10% of their trip related expenditures in Imperial County.
272

Table 4.5-2 Household Trip Expenditures

Expenditure Type

Household Trip 

Expenditure (Lower 

Bound)c in 1998 $

Household Trip Expenditure 

(Upper Bound)d in 1998 $

Food & Beverage 95.27 317.58

Medical 11.68 23.36

Supplies and Services 128.45 256.9

Transportation 24.58 49.16

TOTAL 259.98 647.00

To perform a sensitivity analysis, two estimates were used for each of the categories. The 

first estimate is the mean household trip expenditures, while the second estimate represents a 

lower bound on trip expenditures. The lower bound is assumed to represent the estimated 

portion of the expenditures spent within the local economy. For this study, the following 

proportions were applied to the trip expenditures to derive the estimates that remain in the 

local economy under each expenditure category: 30 percent of food expenditures and 

50 percent of the expenditures on gas, medical services, and supplies and services. The 

preceding proportions represent the local contribution and are partially based on estimates 

developed by Clawson and Knetch (1966) for economies of rural recreational sites near 

federal reserves. In the case of the lodging category, total fees that BLM collected were used 

instead of the estimates from the OHV study. BLM collected $657,578 in total fees in 2000. 

This translates to $616,007 in 1998 dollars. Yuma County in Arizona serves as a starting 

point for some of the visitors to the ISDRA as well as the route from other parts of Arizona. 

As such, there are a number of small towns whose business communities are highly 

dependent on recreational activities in the ISDRA. Any changes in the number and frequency 

of visitors to the ISDRA are likely to impact these towns. Because Yuma County has a high 

unemployment rate (27.5 percent in 2000), any alternative that reduces the number of visitors 

will likely raise the unemployment rate. Assuming that Arizona residents visiting the ISDRA 

spend approximately 30 percent of their trip expenditures in Yuma County, the following trip 

expenditures were developed under each of the management alternatives. As with the 

estimates developed for Imperial County, the low ends represent estimates expected to stay 

within the local area (i.e., Yuma County).

The estimated total trip expenditures (lower and upper bound) associated with each of the 

action alternatives (as well as the baseline condition) for Imperial and Yuma County are 

presented in Tables 4.5-3 and 4.5-4. The estimated total trip expenditures were used to 

analyze the effects on the economies of the two counties. An IMPLAN (Impact Analysis for 

Planning) regional input-output model was constructed for each of the two counties. 

IMPLAN is an input-output modeling and software package that allows the modeler to build 

economic models of regions for impact analysis purposes.
273

Table 4.5-3 Total Household Trip Expenditures by Expenditure Type, Imperial Countya (Million 

1998 $)

Alternatives

2002-2003 

Visitor 

Estimate

2012-2013 

Low Visitor 

Estimate 2012-2013 High Visitor Estimates

Expenditure 

Type Baseline

All 

Alternatives 

2002-2003

All 

Alternatives

Alternative 

1

Alternative 

2

Alternative 

3

Alternative 

4

Lower Bound

Fees 0.62 0.71 1.01 1.47 1.16 1.06 1.28

Food & 

Beverage 

21.68 25.11 106.27 51.73 40.89 37.17 44.97

Medical 2.66 3.08 13.03 6.34 5.01 4.56 5.51

Supplies and 

Services 

29.23 33.85 143.27 69.75 55.13 50.11 60.62

Transportation 5.59 6.48 27.41 13.35 10.55 9.59 11.60

TOTAL 59.77 69.22 290.99 142.64 112.75 102.49 123.98

Upper Bound

Fees 0.62 0.71 1.01 1.47 1.16 1.06 1.28

Food & 

Beverage 

72.26 83.69 354.22 172.45 136.31 123.90 149.88

Medical 5.32 6.16 26.06 12.69 10.03 9.12 11.03

Supplies and 

Services 

58.45 67.70 286.54 139.50 110.27 100.23 121.24

Transportation 11.18 12.95 54.83 26.69 21.10 19.18 23.20

TOTAL 147.82 171.20 722.66 352.80 278.87 253.48 306.63

Source: California Department of Parks and Recreation, 1997; BLM, 2001. 

Numbers may not add up due to independent rounding.

a Imperial County receives all of the expenditures by California residents and 10% of the 

expenditures by Arizona residents.
274

Table 4.5-4 Total Household Trip Expenditures by Expenditure Type, Yuma Countya (Million 1997 

$)

Alternatives

2002-2003 

Visitor 

Estimate

2012-2013 

Low Visitor 

Estimate 2012-2013 High Visitor Estimates

Expenditure 

Type Baseline

All 

Alternatives 

2002-2003

All 

Alternatives

Alternative 

1

Alternative 

2

Alternative 

3

Alternative 

4

Lower Bound

Food & 

Beverage 

1.03 1.19 5.03 2.45 1.93 1.76 2.13

Medical 0.13 0.15 0.62 0.30 0.24 0.22 0.26

Supplies and 

Services 

1.38 1.60 6.78 3.30 2.61 2.37 2.87

Transportation 0.26 0.31 1.30 0.63 0.50 0.45 0.55

TOTAL 2.80 3.24 13.72 6.68 5.28 4.80 5.81

Upper Bound

Food & 

Beverage 

3.42 3.96 16.76 8.16 6.45 5.86 7.09

Medical 0.25 0.29 1.23 0.60 0.47 0.43 0.52

Supplies and 

Services 

2.77 3.20 13.56 6.60 5.22 4.74 5.74

Transportation 0.53 0.61 2.59 1.26 1.00 0.91 1.10

TOTAL 6.97 8.07 34.15 16.62 13.14 11.94 14.55

Source: California Department of Parks and Recreation, 1997; BLM, 2001. 

Numbers may not add up due to independent rounding.

a Yuma County receives 30% of the expenditures by Arizona residents.
275

Impacts

Alternative 1

Imperial County

Estimated trip expenditures at the ISDRA would range from $59.8 million to $147.8 million. 

Table 4.5-5 shows estimated total household trip expenditures by expenditure types under the 

baseline condition. The estimates form the basis of the economic impact analysis.

Table 4.5-5 Total Estimated Household Trip Expenditures 

by Expenditure Type under Baseline Condition, in 1998 Dollars

Expenditure Type

Total Household Trip 

Expenditures (Lower 

Bound) 

in Millions $ 

Total Household 

Trip Expenditures 

(Upper Bound) in 

Millions $

Lodging 0.62 0.62

Food and Beverage 21.68 72.26

Medical 2.66 5.32

Supplies and Services 29.23 58.45

Transportation 5.59 11.18

TOTAL 59.77 147.82

Source: BLM, 2001j; California Department of Parks and Recreation, 

1997.

Numbers may not add up due to independent rounding.

The ISDRA would contribute 1,214 to 3,264 in jobs through direct employment and between 

$23.8 million and $56.1 million in direct personal income to the Imperial County economy. 

In addition to the direct economic impacts of visitor expenditures, ISDRA also contributes to 

the economic well being of Imperial County through secondary economic impacts (indirect 

and induced impacts). Visitor expenditures result in 121 to 304 jobs through indirect 

employment in the region and between 165 and 410 jobs through induced employment. 

Visitor expenditures also generate between $3.6 million and $8.5 million in indirect personal 

income to the region, and between $4.1 million and $9.7 million in induced personal income. 

Table 4.5-6 shows the estimates of direct, indirect, and induced employment and income 

under the baseline condition. 

Employment impacts of the ISDRA under the baseline condition represent between 3 and 8 

percent of the total regional employment of 49,800. Total personal income, on the other 

hand, represents about 1 percent of the total regional personal income (here derived as per 

capita income of $17,550 multiplied by the Census 2000 population estimate for Imperial 

County of 142,361). 
276

Table 4.5-6 Estimates of Direct, Indirect, 

and Induced Impacts under the Baseline Condition

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 1,214 3.264

 Indirect 121 304

 Induced 165 410

Total Employment 1,500 3,978

Personal Income 

 Direct $23.81 million $56.13 million

 Indirect $3.58 million $8.54 million

 Induced $4.08 million $9.65 million

Total Income $31.48 million $74.32 million

Income estimates are in 2000 dollars.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the housing vacancy rate in the county is high (10.3 percent), no adverse impacts to the 

local population regarding population or housing are expected under the baseline condition.

Yuma County

Under this alternative, the estimated trip expenditures range from $2.8 million to about 

$6.0 million. Table 4.5-7 shows estimated total household trip expenditures by expenditure 

types for the baseline condition. 

Table 4.5-7 Total Estimated Household Trip Expenditures 

by Expenditure Type under the Baseline Condition, in 1997 Dollars

Expenditure Type

Total Household Trip 

Expenditures (Lower 

Bound) 

in Millions $ 

Total Household Trip 

Expenditures (Upper 

Bound) in Millions $

Food and 

Beverage 

1.03 3.42

Medical 0.13 0.25

Supplies and 

Services 

1.38 2.77

Transportation 0.26 0.53

TOTAL 2.80 6.97

Source: BLM, 2001; California Department of Parks and Recreation, 

1997.

Numbers may not add up due to independent rounding.
277

The ISDRA would contribute 58 to 158 jobs through direct employment and between $1.0 

million and $2.4 million in direct personal income to the Yuma County economy. In addition 

to the direct economic impacts of visitor expenditures, the ISDRA also contributes to the 

economic well being of Yuma County through secondary economic impacts (indirect and 

induced impacts). Visitor expenditures result in 10 to 24 jobs through indirect employment in 

the region and between 9 and 23 jobs through induced employment. 

The visitor expenditures also generate between $0.2 million and $0.6 million in indirect 

personal income to the region, and between $0.2 million and $0.5 million in induced personal 

income. Table 4.5-8 shows the estimates of direct, indirect, and induced employment and 

income under the baseline condition.

Table 4.5-8 Estimates of Direct, Indirect, 

and Induced Impacts under the Baseline Condition

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 58 158

 Indirect 10 24

 Induced 9 23

Total Employment 76 205

Personal Income 

 Direct $0.98 million $2.44 million

 Indirect $0.23 million $0.57 million

 Induced $0.19 million $0.48 million

Total Income $1.40 million $3.49 million

Income estimates are in 2000 dollars.

The employment impacts of the ISDRA under the baseline condition represent between 

0.2 and 0.4 percent of the total regional employment of 47,600. Total personal income, on the 

other hand, represents between zero and 0.1 percent of total regional personal income (here 

derived as per-capita income of $18,452 multiplied by the Census 2000 population estimate 

for Yuma County of 160,026).

All Action Alternatives: 2002-2003 Visitor Estimates

Imperial County

Under this alternative, estimated trip expenditures range from $69.2 million to 

$171.1 million. Table 4.5-9 shows estimated total household trip expenditures by expenditure 

types for the action alternatives using the 2002-2003 estimates of visitor use. 

The ISDRA would contribute 1,406 to 3,780 jobs through direct employment and between 

$27.6 million and $68.2 million in direct personal income to the Imperial County economy. 

In addition to the direct economic impacts of visitor expenditures, ISDRA would also 

contribute to the economic well being of Imperial County through secondary economic 
278

impacts (indirect and induced impacts). Visitor expenditures result in 140 to 353 jobs through 

indirect employment in the region and between 191 and 475 jobs through induced 

employment.

Table 4.5-9 Total Estimated Household Trip Expenditures by Expenditure 

Type under all action Alternatives, 2002-2003 visitor estimates, in 1998 

Dollars

Expenditure Type

Total Household Trip 

Expenditures (Lower 

Bound) 

in Millions $ 

Total Household Trip 

Expenditures (Upper 

Bound) in Millions $

Lodging 0.71 0.71

Food and Beverage 25.11 83.69

Medical 3.08 6.16

Supplies and 

Services 

33.85 67.70

Transportation 6.48 12.95

TOTAL 69.22 171.20

Source: BLM, 2001; California Department of Parks and Recreation, 

1997.

Numbers may not add up due to independent rounding.

The visitor expenditures would also generate between $4.2 million and $10.5 million in 

indirect personal income to the region, and between $4.7 million and $11.7 million in 

induced personal income. Table 4.5-10 shows the estimates of direct, indirect, and induced 

employment and income under the action alternatives using the 2002-2003 estimates of 

visitor use. 

Table 4.5-10 Estimates of Direct, Indirect, and 

Induced Impacts under all Action Alternatives, 2002-2003 Visitor Use 

Estimates

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 1,406 3,780

 Indirect 140 353

 Induced 191 475

Total Employment 1,737 4,607

Personal Income 

 Direct $27.6 million $68.2 million

 Indirect $4.2 million $10.5 million

 Induced $4.7 million $11.7 million

Total Personal 

Income

$336.5 million $90.3 million

Income estimates are in 2000 dollars.
279

Total employment impacts of the ISDRA under all action alternatives represent between 3 

and 9 percent of the total regional employment of 49,800. Total personal income, on the 

other hand, represent between 3 and 4 percent of total regional personal income. The 

anticipated increase in regional employment and income in Imperial County, compared to the 

baseline conditions, represents a beneficial impact.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the 

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, all alternatives project an increasing visitor supply, which 

could provide additional employment for the local population.

Yuma County

Under this alternative, the estimated trip expenditures range from $3.2 million to 

$8.1 million. Table 4.5-11 shows estimated total household trip expenditures by expenditure 

types for the action alternatives using the 2002-2003 visitor use estimates.

Table 4.5-11 Total Estimated Household Trip 

Expenditures by Expenditure Type, Yuma County in 1997 Dollars

Expenditure Type

Total Household Trip 

Expenditures (Lower 

Bound) 

in Millions $ 

Total Household Trip 

Expenditures (Upper 

Bound) in Millions $

Food and Beverage 1.19 3.96

Medical 0.15 0.29

Supplies and Services 1.60 3.20

Transportation 0.31 0.61

TOTAL 3.24 8.07

Source: BLM, 2001; California Department of Parks and Recreation, 1997.

Numbers may not add up due to independent rounding.

The ISDRA would contribute 67 to 183 jobs through direct employment and between $1.1 

million and $2.8 million in direct personal income to the Yuma County economy. In addition 

to the direct economic impacts of visitor expenditures, the ISDRA would also contribute to 

the economic well being of Yuma County through secondary economic impacts (indirect and 

induced impacts). Visitor expenditures result in 11 to 28 jobs through indirect employment in 

the region and between 10 and 26 jobs through induced employment.

The visitor expenditures also generate between $0.3 million and $0.7 million in indirect 

personal income to the region, and between $0.2 million and $0.6 million in induced personal 

income. Table 4.5-12 shows the estimates of direct, indirect, and induced employment and 

income under the action alternatives using the 2002-2003 visitor use estimates.
280

Table 4.5-12 Estimates of Direct, Indirect, and 

Induced Impacts under All Action Alternatives, 2002-2003 Visitor Use 

Estimates

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 67 183

 Indirect 11 28

 Induced 10 26

Total Employment 88 237

Personal Income 

 Direct $1.13 million $2.82 million

 Indirect $0.26 million $0.67 million

 Induced $0.22 million $0.56 million

Total Personal Income $1.62 million $4.05 million

Income estimates are in 2000 dollars

The employment impacts of the ISDRA under the Recreation Resource Alternative represent 

between 0.2 and 0.5 percent of the total regional employment of 47,600. Total personal 

income, on the other hand, represents 0.1 percent of total regional personal income under 

both the high and low expenditure estimates. Therefore, a negligible to beneficial impact on 

regional employment and income in Yuma County is anticipated.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the 

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, all alternatives project an increasing visitor supply, which 

could provide additional employment for the local population.

All Action Alternatives: Low 2012-2013 Visitor Use Estimates

Imperial County

Under this alternative, estimated trip expenditures range from $97.7 million to 

$241.6 million. Table 4.5-13 shows estimated total household trip expenditures by 

expenditure types for all the action Alternatives using low 2012-2013 visitor use estimate. 
281

Table 4.5-13 Total Estimated Household Trip Expenditures by Expenditure 

Type under all Alternatives, Low 2012-2013 Visitor Use Estimate, 1998

Dollars

Expenditure Type

Total Household Trip 

Expenditures (Lower 

Bound) 

in Millions $ 

Total Household 

Trip Expenditures 

(Upper Bound) in 

Millions $

Lodging 1.01 1.01

Food and Beverage 35.42 118.07

Medical 4.34 8.69

Supplies and Services 47.76 95.51

Transportation 9.14 18.28

TOTAL 97.67 241.56

Source: BLM, 2001; California Department of Parks and Recreation, 1997.

Numbers may not add up due to independent rounding.

The ISDRA would contribute 1,984 to 5,334 jobs through direct employment and between 

$38.9 million and $96.2 million in direct personal income to the Imperial County economy. 

In addition to the direct economic impacts of visitor expenditures, the ISDRA would also 

contribute to the economic well being of Imperial County through secondary economic 

impacts (indirect and induced impacts). Visitor expenditures result in 197 to 498 jobs through 

indirect employment in the region and between 270 and 670 jobs through induced 

employment. 

The visitor expenditures would also generate between $5.9 million and $14.8 million in 

indirect personal income to the region, and between $6.7 million and $16.5 million in 

induced personal income. Table 4.5-14 shows the estimates of direct, indirect, and induced 

employment and income under all action alternatives and using low 2012-2013 visitor use 

estimates. 

Total employment impacts of the ISDRA under the action alternatives represent between 5 

and 13 percent of the total regional employment of 49,800. Total personal income, on the 

other hand, represents between 2 and 5 percent of total regional personal income. The 

anticipated increase in regional employment and income in Imperial County under the action 

alternatives, compared to existing conditions, represents a beneficial impact.
282

Table 4.5-14 Estimates of Direct, Indirect, and 

Induced Impacts under All Action Alternatives, 2012-2013 Low Visitor 

Use Estimates

Low Expenditure 

Estimates 

High 

Expenditure 

Estimates

Employment

 Direct 1,984 5,334

 Indirect 197 498

 Induced 270 670

Total Employment 2,450 6,501

Personal Income 

 Direct $38.91 million $96.15 million

 Indirect $5.85 million $14.76 million

 Induced $6.67 million $16.55 million

Total Personal Income $51.43 million $127.46 million

Income estimates are in 2000 dollars.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the 

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, all alternatives project an increasing visitor supply, which 

could provide additional employment for the local population.

Yuma County

Under this alternative, the estimated trip expenditures range from $4.6 million to 

$11.4 million. Table 4.5-15 shows estimated total household trip expenditures by expenditure 

types for all the action alternatives using low 2012-2013 visitor use estimate.
283

Table 4.5-15 Total Estimated Household Trip Expenditures by Expenditure 

Type under All Action Alternatives, Low 2012-2013 Visitor Use Estimate, 

1997 Dollars

Expenditure Type

Total Household Trip 

Expenditures (Lower 

Bound) 

in Millions $ 

Total Household Trip 

Expenditures (Upper 

Bound) in Millions $

Food and Beverage 1.68 5.59

Medical 0.21 0.41

Supplies and Services 2.26 4.52

Transportation 0.43 0.86

TOTAL 4.57 11.38

Source: BLM, 2001; California Department of Parks and Recreation, 1997.

Numbers may not add up due to independent rounding.

The ISDRA would contribute 94 to 258 jobs through direct employment and between 

$1.60 million and $3.99 million in direct personal income to the Yuma County economy. In 

addition to the direct economic impacts of visitor expenditures, the ISDRA would also 

contribute to the economic well being of Yuma County through secondary economic impacts 

(indirect and induced impacts). Visitor expenditures result in 15 to 39 jobs through indirect 

employment in the region and between 15 and 37 jobs through induced employment. 

The visitor expenditures also generate between $0.4 million and $0.9 million in indirect 

personal income to the region, and between $0.3 million and $0.8 million in induced personal 

income. Table 4.5-16 shows the estimates of direct, indirect, and induced employment and 

income under all the action alternatives using low 2012-2013 visitor use estimate. 

Table 4.5-16 Estimates of Direct, Indirect, and Induced Impacts 

under All Action Alternatives, Low 2012-2013 Visitor Use Estimate

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 94 258

 Indirect 15 39

 Induced 15 37

Total Employment 124 334

Personal Income 

 Direct $1.60 million $3.99 million

 Indirect $0.37 million $0.94 million

 Induced $0.31 million $0.79 million

Total Personal Income $2.28 million $5.71 million

Income estimates are in 2000 dollars.
284

Total employment impacts of the ISDRA under this alternative represent between 0.3 and 0.7 

percent of the total regional employment of 47,600. Total personal income, on the other 

hand, represents between 0.1 and 0.2 percent of total regional personal income. Thus, this 

alternative would have a negligible to beneficial impact on regional employment and income 

in Yuma County.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the 

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, all alternatives project an increasing visitor supply, which 

could provide additional employment for the local population.

Alternative 1: High 2012-2013 Visitor Use Estimate

Imperial County

Estimated trip expenditures range from $142.6 million to $352.8 million. Table 4.5-17 shows 

estimated total household trip expenditures by expenditure types for Alternative 1 using high 

2012-2013 visitor use estimates. 

The ISDRA would contribute 2,897 to 7,790 jobs through direct employment and between 

$56.8 million and $140.4 million in direct personal income to the Imperial County economy. 

In addition to the direct economic impacts of visitor expenditures, ISDRA would also 

contribute to the economic well being of Imperial County through secondary economic 

impacts (indirect and induced impacts). Visitor expenditures result in 287 to 727 jobs through 

indirect employment in the region and between 394 and 978 jobs through induced 

employment.

Table 4.5-17 Total Estimated Household Trip Expenditures by Expenditure 

Type under Alternative 1 with High 2012-2013 Visitor Use Estimates, 1998 

Dollars

Expenditure Type

Total Household Trip 

Expenditures 

(Lower Bound) 

in Millions $ 

Total Household Trip 

Expenditures (Upper 

Bound) 

in Millions $

Lodging 1.47 1.47

Food and Beverage 51.73 172.45

Medical 6.34 12.69

Supplies and 

Services 

69.75 139.50

Transportation 13.35 26.69

TOTAL 142.64 352.80

Source: BLM, 2001; California Department of Parks and Recreation, 1997.

Numbers may not add up due to independent rounding.
285

The visitor expenditures would also generate between $8.6 million and $21.6 million in 

indirect personal income to the region, and between $9.7 million and $24.2 million in 

induced personal income. Table 4.5-18 shows the estimates of direct, indirect, and induced 

employment and income under Alternative 1 with high 2012-2013 visitor use estimates. 

Table 4.5-18 Estimates of Direct, Indirect, and Induced Impacts 

under Alternative 1 with High 2012-2013 Visitor Use Estimates

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 2,897 7,790

 Indirect 287 727

 Induced 394 978

Total Employment 3,578 9,495

Personal Income 

 Direct $56.83 million $140.43 million

 Indirect $8.55 million $21.56 million

 Induced $9.74 million $24.16 million

Total Personal Income $75.12 million $186.15 million

Income estimates are in 2000 dollars.

Total employment impacts of the ISDRA under Alternative 1 (high 2012-2013 visitor use 

estimates) represent between 7 and 19 percent of the total regional employment of 49,800. 

Total personal income, on the other hand, represents between 3 and 7 percent of total 

regional personal income. The anticipated increase in regional employment and income in 

Imperial County under this alternative represents a beneficial impact relative to existing 

conditions.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the 

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, this alternative projects the highest increase in visitor 

supply, which could provide the greatest additional employment for the local population.

Yuma County

Under Alternative 1 (high 2012-2013 visitor use estimates), the estimated trip expenditures 

range from $6.7 million to $16.6 million. Table 4.5-19 shows estimated total household trip 

expenditures by expenditure types for Alternative 1 using high 2012-2013 visitor use 

estimates.
286

Table 4.5-19 Total Estimated Household Trip Expenditures by 

Expenditure Type under Alternative 1 with High 2012-2013 Visitor 

Use Estimates, 1997 Dollars

Expenditure Type

Total Household Trip 

Expenditures 

(Lower Bound) 

in Millions $ 

Total Household Trip 

Expenditures (Upper 

Bound) 

in Millions $

Food and Beverage 2.45 8.16

Medical 0.30 0.60

Supplies and 

Services 

3.30 6.60

Transportation 0.63 1.26

TOTAL 6.68 16.62

Source: BLM, 2001; California Department of Parks and Recreation, 

1997.

Numbers may not add up due to independent rounding.

The ISDRA would contribute 137 to 377 jobs through direct employment and between $2.3 

million and $5.8 million in direct personal income to the Yuma County economy. In addition 

to the direct economic impacts of visitor expenditures, ISDRA would also contribute to the 

economic well being of Yuma County through secondary economic impacts (indirect and 

induced impacts). Visitor expenditures result in 23 to 57 jobs through indirect employment in 

the region and between 21 and 54 jobs through induced employment. 

The visitor expenditures also generate between $0.5 million and $1.4 million in indirect 

personal income to the region, and between $0.5 million and $1.2 million in induced personal 

income. Table 4.5-20 shows the estimates of direct, indirect, and induced employment and 

income under Alternative 1 with high 2012-2013 visitor use estimates. 

Table 4.5-20 Estimates of Direct, Indirect, and Induced 

Impacts under Alternative 1 with High 2012-2013 Visitor Use Estimates

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 137 377

 Indirect 23 57

 Induced 21 54

Total Employment 181 488

Personal Income 

 Direct $2.33 million $5.82 million

 Indirect $0.54 million $1.37 million

 Induced $0.46 million $1.15 million

Total Personal Income $3.33 million $8.34 million

Income estimates are in 2000 dollars.
287

Total employment impacts of the ISDRA under Alternative 1 (high 2012-2013 visitor use 

estimates) represent between 0.4 and 1.0 percent of the total regional employment of 47,600. 

Total personal income, on the other hand, represents between 0.1 and 0.3 percent of total 

regional personal income. Thus, this alternative would have a negligible to beneficial impact 

on regional employment and income in Yuma County.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the 

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, this alternative projects the highest visitor supply, which 

could provide the greatest additional employment for the local population.

Alternative 2: High 2012-2013 Visitor Use Estimate

Imperial County

Estimated trip expenditures range from $112.8 million to $278.9 million. Table 4.5-21 shows 

estimated total household trip expenditures by expenditure types for Alternative 2 using high 

2012-2013 visitor use estimates. 

The ISDRA would contribute 2,290 to 6,158 jobs through direct employment and between 

$44.9 million and $111.0 million in direct personal income to the Imperial County economy. 

In addition to the direct economic impacts of visitor expenditures, ISDRA would also 

contribute to the economic well being of Imperial County through secondary economic 

impacts (indirect and induced impacts). Visitor expenditures result in 227 to 574 jobs through 

indirect employment in the region and between 312 and 773 jobs through induced 

employment.

Table 4.5-21 Total Estimated Household Trip Expenditures by Expenditure 

Type under Alternative 2 with High 2012-2013 Visitor Use Estimates, 1998 

Dollars

Expenditure Type

Total Household Trip 

Expenditures (Lower 

Bound) 

in Millions $ 

Total Household Trip 

Expenditures (Upper 

Bound) in Millions $

Lodging 1.16 1.16

Food and Beverage 40.89 136.31

Medical 5.01 10.03

Supplies and Services 55.13 110.27

Transportation 10.55 21.10

TOTAL 112.75 278.87

Source: BLM, 2001; California Department of Parks and Recreation, 1997.

Numbers may not add up due to independent rounding.
288

The visitor expenditures would also generate between $6.8 million and $17.0 million in 

indirect personal income to the region, and between $7.7 million and $19.1 million in 

induced personal income. Table 4.5-22 shows the estimates of direct, indirect, and induced 

employment and income under Alternative 2 with high 2012-2013 visitor use estimates. 

Table 4.5-22 Estimates of Direct, Indirect, and Induced Impacts 

under Alternative 2 with High 2012-2013 Visitor Use Estimates

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 2,290 6,158

 Indirect 227 574

 Induced 312 773

Total Employment 2,829 7,505

Personal Income 

 Direct $44.92 million $111.00 million

 Indirect $6.75 million $17.04 million

 Induced $7.70 million $19.10 million

Total Personal Income $59.38 million $147.14 million

Income estimates are in 2000 dollars.

Total employment impacts of the ISDRA under Alternative 2 (high 2012-2013 visitor use 

estimates) represent between 6 and 15 percent of the total regional employment of 49,800. 

Total personal income, on the other hand, represents between 2 and 6 percent of total 

regional personal income. The anticipated increase in regional employment and income in 

Imperial County under this alternative represents a beneficial impact relative to existing 

conditions.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the 

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, Alternative 2 projects an increasing visitor supply, which 

could provide additional employment for the local population, although this increase would 

not be as great as Alternatives 1 and 4. However, it would be greater that alternative 3.

Yuma County

Under Alternative 2 (high 2012-2013 visitor use estimates), the estimated trip expenditures 

range from $5.3 million to $13.1 million. Table 4.5-23 shows estimated total household trip 

expenditures by expenditure types for Alternative 2 using high 2012-2013 visitor use 

estimates. 
289

Table 4.5-23 Total Estimated Household Trip Expenditures by Expenditure 

Type under Alternative 2 with High 2012-2013 Visitor Use Estimates, 1997 

Dollars

Expenditure Type

Total Household Trip 

Expenditures (Lower 

Bound) 

in Millions $ 

Total Household Trip 

Expenditures (Upper 

Bound) in Millions $

Food and Beverage 1.93 6.45

Medical 0.24 0.47

Supplies and Services 2.61 5.22

Transportation 0.50 1.00

TOTAL 5.28 13.14

Source: BLM, 2001; California Department of Parks and Recreation, 1997.

Numbers may not add up due to independent rounding.

The ISDRA would contribute 108 to 298 jobs through direct employment and between $1.8 

million and $4.6 million in direct personal income to the Yuma County economy. In addition 

to the direct economic impacts of visitor expenditures, ISDRA would also contribute to the 

economic well being of Yuma County through secondary economic impacts (indirect and 

induced impacts). Visitor expenditures result in 18 to 45 jobs through indirect employment in 

the region and between 17 and 42 jobs through induced employment. 

The visitor expenditures also generate between $0.4 million and $1.1 million in indirect 

personal income to the region, and between $0.4 million and $0.9 million in induced personal 

income. Table 4.5-24 shows the estimates of direct, indirect, and induced employment and 

income under Alternative 2 with high 2012-2013 visitor use estimates.

Table 4.5-24 Estimates of Direct, Indirect, and Induced Impacts 

under Alternative 2 with High 2012-2013 Visitor Use Estimates

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 108 298

 Indirect 18 45

 Induced 17 42

Total Employment 143 386

Personal Income 

 Direct $1.84 million $4.60 million

 Indirect $0.43 million $1.08 million

 Induced $0.36 million $0.91 million

Total Personal Income $2.63 million $6.59 million

Income estimates are in 2000 dollars.
290

Total employment impacts of the ISDRA under Alternative 2 (high 2012-2013 visitor use 

estimates) represent between 0.3 and 0.8 percent of the total regional employment of 47,600. 

Total personal income, on the other hand, represents between 0.1 and 0.2 percent of total 

regional personal income. Thus, this alternative would have a beneficial impact on regional 

employment and income in Yuma County.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the 

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, Alternative 2 projects an increasing visitor supply, which 

could provide additional employment for the local population, although this increase would 

not be as great as Alternatives 1 and 4. However, it would be greater that alternative 3.

Alternative 3: High 2012-2013 Visitor Use Estimate

Imperial County

Estimated trip expenditures range from $102.5 million to $253.5 million. Table 4.5-25 shows 

estimated total household trip expenditures by expenditure types for Alternative 3 using high 

2012-2013 visitor use estimates. 

The ISDRA would contribute 2,081 to 5,597 jobs through direct employment and between 

$40.8 million and $100.9 million in direct personal income to the Imperial County economy. 

In addition to the direct economic impacts of visitor expenditures, ISDRA would also

contribute to the economic well being of Imperial County through secondary economic 

impacts (indirect and induced impacts). Visitor expenditures result in 283 to 522 jobs through 

indirect employment in the region and between 283 and 703 jobs through induced 

employment.

Table 4.5-25 Total Estimated Household Trip Expenditures by Expenditure 

Type 

under Alternative 3 with High 2012-2013 Visitor Use Estimates, 1998 

Dollars

Expenditure Type

Total Household Trip 

Expenditures (Lower 

Bound) 

in Millions $ 

Total Household Trip 

Expenditures (Upper 

Bound) in Millions $

Lodging 1.06 1.06

Food and Beverage 37.17 123.90

Medical 4.56 9.12

Supplies and Services 50.11 100.23

Transportation 9.59 19.18

TOTAL 102.49 253.48

Source: BLM, 2001; California Department of Parks and Recreation, 1997.

Numbers may not add up due to independent rounding.
291

The visitor expenditures would also generate between $6.1 million and $15.5 million in 

indirect personal income to the region, and between $7.0 million and $17.4 million in 

induced personal income. Table 4.5-26 shows the estimates of direct, indirect, and induced 

employment and income under Alternative 3 with high 2012-2013 visitor use estimates. 

Table 4.5-26 Estimates of Direct, Indirect, and Induced Impacts 

under Alternative 3 with High 2012-2013 Visitor Use Estimates

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 2,081 5,597

 Indirect 207 522

 Induced 283 703

Total Employment 2,571 6,822

Personal Income 

 Direct $40.83 million $100.90 million

 Indirect $6.14 million $15.49 million

 Induced $7.00 million $17.36 million

Total Personal Income $53.97 million $133.75 million

Income estimates are in 2000 dollars.

Total employment impacts of the ISDRA under Alternative 3 (high 2012-2013 visitor 

estimates) represent between 5 and 14 percent of the total regional employment of 49,800. 

Total personal income, on the other hand, represents between 2 and 5 percent of total 

regional personal income. The anticipated increase in regional employment and income in 

Imperial County under this alternative represents a beneficial impact relative to existing 

conditions.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the 

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, Alternative 3 projects an increasing visitor supply, which 

could provide additional employment for the local population, although this increase would 

not be as great as Alternatives 1, 2 and 4. 

Yuma County

Under Alternative 3 (high 2012-2013 visitor use estimates), the estimated trip expenditures 

range from $4.8 million to $11.9 million. Table 4.5-27 shows estimated total household trip 

expenditures by expenditure types for Alternative 3 using high 2012-2013 visitor use 

estimates.
292

Table 4.5-27 Total Estimated Household Trip Expenditures by Expenditure 

Type 

under Alternative 3 with High 2012-2013 Visitor Use Estimates, 1997 

Dollars

Expenditure Type

Total Household Trip 

Expenditures 

(Lower Bound) 

in Millions $ 

Total Household Trip 

Expenditures (Upper 

Bound) 

in Millions $

Food and Beverage 1.76 5.86

Medical 0.22 0.43

Supplies and Services 2.37 4.74

Transportation 0.45 0.91

TOTAL 4.80 11.94

Source: BLM, 2001; California Department of Parks and Recreation, 1997.

Numbers may not add up due to independent rounding.

The ISDRA would contribute 99 to 271 jobs through direct employment and between $1.7 

million and $4.2 million in direct personal income to the Yuma County economy. In addition 

to the direct economic impacts of visitor expenditures, ISDRA would also contribute to the 

economic well being of Yuma County through secondary economic impacts (indirect and 

induced impacts). Visitor expenditures result in 16 to 41 jobs through indirect employment in 

the region and between 15 and 39 jobs through induced employment. 

The visitor expenditures also generate between $0.4 million and $1.0 million in indirect 

personal income to the region, and between $0.3 million and $0.8 million in induced personal 

income. Table 4.5-28 shows the estimates of direct, indirect, and induced employment and 

income under Alternative 3 with high 2012-2013 visitor use estimates.

Table 4.5-28 Estimates of Direct, Indirect, and Induced Impacts 

under Alternative 3 with High 2012-2013 Visitor Use Estimates

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 99 271

 Indirect 16 41

 Induced 15 39

Total Employment 130 351

Personal Income 

 Direct $1.68 million $4.18 million

 Indirect $0.39 million $0.98 million

 Induced $0.33 million $0.83 million

Total Personal Income $2.39 million $5.99 million

Income estimates are in 2000 dollars.
293

Total employment impacts of the ISDRA under Alternative 3 (high 2012-2013 visitor use 

estimates) represent between 0.3 and 0.7 percent of the total regional employment of 47,600. 

Total personal income, on the other hand, represents between 0.1 and 0.2 percent of total 

regional personal income. Thus, this alternative would have a negligible to beneficial impact 

on regional employment and income in Yuma County.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, Alternative 3 projects an increasing visitor supply, which 

could provide additional employment for the local population, although this increase would 

not be as great as Alternatives 1, 2 and 4. 

Alternative 4: High 2012-2013 Visitor Use Estimate

Imperial County

Estimated trip expenditures range from $124.0 million to $306.6 million. Table 4.5-29 shows 

estimated total household trip expenditures by expenditure types for Alternative 4 using high 

2012-2013 visitor use estimates. 

The ISDRA would contribute 2,518 to 6,771 jobs through direct employment and between 

$49.4 million and $122.1 million in direct personal income to the Imperial County economy. 

In addition to the direct economic impacts of visitor expenditures, ISDRA would also 

contribute to the economic well being of Imperial County through secondary economic 

impacts (indirect and induced impacts). Visitor expenditures result in 250 to 632 jobs through 

indirect employment in the region and between 343 and 850 jobs through induced 

employment.

Table 4.5-29 Total Estimated Household Trip Expenditures by 

Expenditure Type 

under Alternative 4 with High 2012-2013 Visitor Use Estimates, 1998 

Dollars

Expenditure Type

Total Household Trip 

Expenditures 

(Lower Bound) 

in Millions $ 

Total Household 

Trip Expenditures 

(Upper Bound) 

in Millions $

Lodging 1.28 1.28

Food and Beverage 44.97 149.88

Medical 5.51 11.03

Supplies and Services 60.62 121.24

Transportation 11.60 23.20

TOTAL 123.98 306.63

Source: BLM, 2001; California Department of Parks and Recreation, 

1997.

Numbers may not add up due to independent rounding.
294

The visitor expenditures would also generate between $7.4 million and $18.7 million in 

indirect personal income to the region, and between $8.5 million and $21.0 million in 

induced personal income. Table 4.5-30 shows the estimates of direct, indirect, and induced 

employment and income under Alternative 4 with high 2012-2013 visitor use estimates. 

Table 4.5-30 Estimates of Direct, Indirect, and Induced Impacts 

under Alternative 4 with High 2012-2013 Visitor Use Estimates

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 2,581 6,771

 Indirect 250 632

 Induced 343 850

Total Employment 3,111 8,252

Personal Income 

 Direct $49.39 million $122.05 million

 Indirect $7.43 million $18.74 million

 Induced $8.47 million $21.00 million

Total Personal Income $65.29 million $161.79 million

Income estimates are in 2000 dollars.

Total employment impacts of the ISDRA under Alternative 4 (high 2012-2013 visitor use 

estimates) represent between 6 and 17 percent of the total regional employment of 49,800. 

Total personal income, on the other hand, represents between 3 and 6 percent of total 

regional personal income. The anticipated increase in regional employment and income in 

Imperial County under this alternative represents a beneficial impact relative to existing 

conditions.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the 

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, Alternative 4 projects an increasing visitor supply, which 

could provide additional employment for the local population. This increase would be 

greater that Alternatives 2 and 3, but not as much as Alternative 1.

Yuma County

Under Alternative 4 (high 2012-2013 visitor use estimates), the estimated trip expenditures 

range from $5.8 million to $14.5 million. Table 4.5-31 shows estimated total household trip 

expenditures by expenditure types for Alternative 4 using high 2012-2013 visitor use 

estimates.
295

Table 4.5-31 Total Estimated Household Trip Expenditures by 

Expenditure Type under Alternative 4 with High 2012-2013 Visitor Use 

Estimates, 1997 Dollars

Expenditure Type

Total Household Trip 

Expenditures 

(Lower Bound) 

in Millions $ 

Total Household 

Trip Expenditures 

(Upper Bound) 

in Millions $

Food and Beverage 2.13 7.09

Medical 0.26 0.52

Supplies and Services 2.87 5.74

Transportation 0.55 1.10

TOTAL 5.81 14.45

Source: BLM, 2001; California Department of Parks and Recreation, 

1997.

Numbers may not add up due to independent rounding.

The ISDRA would contribute 119 to 328 jobs through direct employment and between $2.0 

million and $5.1 million in direct personal income to the Yuma County economy. In addition 

to the direct economic impacts of visitor expenditures, ISDRA would also contribute to the 

economic well being of Yuma County through secondary economic impacts (indirect and 

induced impacts). Visitor expenditures result in 20 to 50 jobs through indirect employment in 

the region and between 19 and 47 jobs through induced employment. 

The visitor expenditures also generate between $0.5 million and $1.2 million in indirect 

personal income to the region, and between $0.4 million and $1.0 million in induced personal 

income. Table 4.5-32 shows the estimates of direct, indirect, and induced employment and 

income under Alternative 4 with high 2012-2013 visitor use estimates.

table 4.5-32 Estimates of Direct, Indirect, and Induced Impacts 

under Alternative 4 with High 2012-2013 Visitor Use Estimates

Low Expenditure 

Estimates 

High Expenditure 

Estimates

Employment

 Direct 119 328

 Indirect 20 50

 Induced 19 47

Total Employment 157 424

Personal Income 

 Direct $2.03 million $5.06 million

 Indirect $0.47 million $1.19 million

 Induced $0.40 million $1.10 million

Total Personal Income $2.90 million $7.25 million

Income estimates are in 2000 dollars.
296

Total employment impacts of the ISDRA under Alternative 4 (high 2012-2013 visitor use 

estimates) represent between 0.3 and 0.9 percent of the total regional employment of 47,600. 

Total personal income, on the other hand, represents between 0.1 and 0.3 percent of total 

regional personal income. Thus, this alternative would have a negligible to beneficial impact 

on regional employment and income in Yuma County.

Because most of the visitors to the ISDRA are temporary visitors (not moving into the area) 

and the competition for local housing, local jobs and local sources of income between the 

recreational users of ISDRA and the local population under all the action alternatives (using 

the 2002-2003 visitor use estimates) are negligible, no adverse impacts on population or 

housing are expected. In addition, Alternative 4 projects an increasing visitor supply, which 

could provide additional employment for the local population. This increase would be 

greater that Alternatives 2 and 3, but not as much as Alternative 1.

Summary of Impacts

Alternative 1 (high 2012-2013 visitor use estimates) results in the highest socioeconomic 

benefits in terms of employment and personal income because it is the alternative that results 

in the highest number of visits. Tables 4.5-33 through 4.5-36 summarize the employment and 

personal income impacts for Imperial and Yuma Counties. As discussed in the introduction 

to this section and in Section 3.1 and 4.1, Recreation, it is important to note that much of the 

economic activity associated with Alternative 1 is attributable to increased visitor use on six 

major holiday weekends. The increased revenues of Alternative 1 (in comparison to the 

other alternatives) must be assessed in consideration of the basic premise of lawful activity 

that defines those action alternatives (Alternatives 2, 3, and 4). None of the alternatives 

would result in adverse impacts to socioeconomics. 

Environmental Justice Analysis

This section was prepared in compliance with Presidential Executive Order (EO) 12898, 

Federal Actions to Address Environmental Justice in Minority Populations and Low-Income 

Populations (EO 12898) dated February 11, 1994. The purpose of this section is to determine 

whether or not disproportionately high and adverse human health or environmental effects 

would result to minority and/or low-income populations from implementing the proposed 

alternatives. This analysis focuses on the populations located within the area potentially 

affected by the alternatives. In accordance with EO 12898, this analysis documents where 

minority and low-income populations reside and examines where the high and adverse 

impacts (as reported in the various environmental analysis sections of this EIS) fall relative to 

these populations. This section also discusses the specific outreach efforts made to involve 

minority and low-income populations in the decision making process.

Overview of Executive Order 12898

EO 12898, issued by President Clinton in 1994, requires that “each Federal agency shall 

make achieving environmental justice part of its mission by identifying and addressing, as 

appropriate, disproportionately high and adverse human health or environmental effects of its 
297

programs, policies, and activities on minority populations and low-income populations... .” In 

his memorandum transmitting EO 12898 to federal agencies, President Clinton further 

specified that, “each Federal agency shall analyze the environmental effects, including 

human health, economic and social effects, of Federal actions, including effects on minority 

communities and low-income communities, when such analysis is required by the National 

Environmental Policy Act of 1969.” Guidance on how to implement EO 12898 and conduct 

an Environmental Justice analysis has been issued by the President’s Council on 

Environmental Quality (CEQ, 1997).

Table 4.5-33 Estimates of Employment Impacts, Imperial County

Alternatives

2002-2003 

Visitor 

Estimate

2012-2013 

Low Visitor 

Estimate 2012-2013 High Visitor Estimates

Expenditure 

Type

Baselin

e

All 

Alternative

s 2002-

2003

All 

Alternatives

Alternative 

1

Alternative 

2

Alternative 

3

Alternative 

4

Lower Bound

Direct 1,214 1,406 1,984 2,897 2,290 2,081 2,518

Indirect 121 140 197 287 227 207 250

Induced 165 191 270 394 312 283 343

Total 

Employment 

1,500 1,737 2,450 3,578 2,829 2,571 3,111

Upper Bound

Direct 3,264 3,780 5,334 7,790 6,158 5,597 6,771

Indirect 304 353 498 727 574 522 632

Induced 410 475 670 978 773 703 850

Total 

Employment

3,978 4,607 6,501 9,495 7,505 6,822 8,252
298

Table 4.5-34 Estimates of Personal Income Impacts, Imperial County (Million 2000 $)

Alternatives

2002-2003 

Visitor 

Estimate

2012-2013 

Low Visitor 

Estimate 2012-2013 High Visitor Estimates

Expenditure 

Type Baseline

All 

Alternatives 

2002-2003

All 

Alternatives

Alternative 

1

Alternative 

2

Alternative 

3

Alternative 

4

Lower Bound

Direct 23.8 27.6 38.91 56.8 44.9 40.8 49.4

Indirect 3.6 4.2 5.85 8.6 6.8 6.1 7.4

Induced 4.1 4.7 6.67 9.7 7.7 7.0 8.5

Total 

Personal 

Income 

31.5 36.5 51.43 75.1 59.4 54.0 65.3

Upper Bound

Direct 56.1 68.2 96.15 140.4 111.0 100.9 122.1

Indirect 8.5 10.5 14.76 21.6 17.0 15.5 18.7

Induced 9.7 11.7 16.55 24.2 19.1 17.4 21.0

Total 

Personal 

Income

74.3 90.3 127.46 186.2 147.1 133.8 161.8

Table 4.5-35 Estimates of Employment Impacts, Yuma County

Alternatives

2002-2003 

Visitor 

Estimate

2012-2013 

Low Visitor 

Estimate 2012-2013 High Visitor Estimates

Expenditure 

Type Baseline

All 

Alternatives 

2002-2003

All 

Alternatives

Alternative 

1

Alternative 

2

Alternative 

3

Alternative 

4

Lower Bound

Direct 58 67 94 137 108 99 119

Indirect 10 11 15 23 18 16 20

Induced 9 10 15 21 17 15 19

Total 

Employment 

76 88 124 181 143 130 157

Upper Bound

Direct 158 183 258 377 298 271 328

Indirect 24 28 39 57 45 41 50

Induced 23 26 37 54 42 39 47

Total 

Employment

205 237 334 488 386 351 424
299

Table 4.5-36 Estimates of Personal Income Impacts, Yuma County (Million 2000 $)

Alternatives

2002-2003 

Visitor 

Estimate

2012-2013 

Low Visitor 

Estimate 2012-2013 High Visitor Estimates

Expenditure 

Type Baseline

All 

Alternatives 

2002-2003

All 

Alternatives

Alternative 

1

Alternative 

2

Alternative 

3

Alternative 

4

Lower Bound

Direct 1.0 1.1 1.6 2.3 1.8 1.7 20.3

Indirect 0.2 0.3 0.4 0.5 0.4 0.4 0.5

Induced 0.2 0.2 0.3 0.5 0.4 0.3 0.4

Total 

Personal 

Income 

1.4 1.6 2.3 3.3 2.6 2.4 2.9

Upper Bound

Direct 2.4 2.8 4.0 5.8 4.6 4.2 5.1

Indirect 0.6 0.7 0.9 1.4 1.1 1.0 1.2

Induced 0.5 0.6 0.8 1.2 0.9 0.8 1.0

Total 

Personal 

Income

3.5 4.1 5.7 8.3 6.6 6.0 7.3

Studies Performed and Coordination Conducted

Methodology and Approach

The alternatives were evaluated for compliance with EO 12898. For this type of analysis, 

three fundamental evaluation measures are used.

1. A determination is made as to which impacts of the alternatives are high and adverse.

The series of environmental analyses prepared for the ISDRA RAMP EIS were reviewed, 

and discussions with the environmental professionals who prepared these sections were 

conducted to determine which environmental or human health impacts could reach the level 

of high and adverse after proposed mitigation measures were implemented. Neither EO 

12898 nor any of the environmental justice guidance documents contains official guidance on 

the definition of “high and adverse.” For purposes of this analysis, adverse impacts identified 

by the professional analysts working on this EIS as “significant” under NEPA were 

considered to be synonymous with high and adverse impacts as described in EO 12898.

2. A determination is made as to whether minority or low-income populations exist 

within the high and adverse impact zones.

For information on the distribution of minority and low-income populations in the vicinity of 

the Plan Area, both 2000 and 1990 census data were used. Race and income data were 
300

reviewed at the finest level available from the census (i.e., Census Block for race, and Census 

Block Group for income). At the time of this analysis, race data from the 2000 census were 

available and were reviewed. Income data from the 2000 census were not scheduled to be 

released until April 2002. In lieu of these newer data, 1990 census data on income were 

reviewed.

3. The spatial distribution of high and adverse impacts is reviewed to determine if these 

impacts are likely to fall disproportionately on the minority or low-income population.

Because there is no specific guidance in EO 12898, the test of disproportionality is made on 

the basis described in the U.S. Environmental Protection Agency’s (EPA) Draft Revised 

Guidance for Investigating Title VI Administrative Complaints Challenging Permits (U.S. 

EPA, June 2000). This guidance suggests using two to three standard deviations above the 

mean as a quantitative measure of disparate effect.

While the first two elements of this approach were conducted, no detailed distribution 

analysis was required to make a final determination. This was because professional analysts 

in each environmental and human health discipline reviewed for this EIS determined that no 

high and adverse (i.e., NEPA significant) human health or environmental effects were 

expected to remain after implementation of proposed mitigation measures.

Outreach to Minority and Low-Income Populations

EO 12898 requires federal agencies to ensure effective public participation and access to 

information. Consequently, a key component of compliance with EO 12898 is outreach to the 

potentially affected minority and/or low-income population to discover issues of importance 

that may not otherwise be apparent. Outreach to affected communities was conducted as part 

of the decion making process. 

Impact Analysis

The ISDRA extends from the central to the southeastern region of Imperial County, 

California. The area encompassed by the recreation area boundary and the areas immediately 

adjacent to this boundary are largely unpopulated.

Distribution of the Minority Population

Based on the 2000 census, the total population of Imperial County is 142,361. The minority 

population comprises approximately 80 percent of this total population. Several of the 

Census Blocks in the vicinity of the ISDRA are above 50 percent minority. These Census 

Blocks have minority population densities high enough (i.e., greater than 50 percent) to be 

considered minority populations based on the guidance contained in CEQ (1997).

Distribution of the Low-Income Population

Based on the 1990 census (the most recent census for which income data are available), the 

total population of Imperial County was 109,303. The low-income population comprised 

approximately 24 percent of this total population. Unlike the CEQ (1997) guidance on 
301

minority population, none of the environmental justice guidance documents contains a 

quantitative definition of how many low-income individuals it takes to comprise a lowincome population. In the absence of guidance, for this analysis the density used to identify 

minority populations (i.e., 50 percent or greater) was also used to identify low-income 

populations. There is one Census Block Group southeast of the ISDRA with 50 percent or 

more low-income population.

As discussed in the Methodology and Approach section above, for purposes of this analysis, 

NEPA significant adverse impacts are considered synonymous with high and adverse 

impacts as described in EO 12898. As reported in the series of environmental analyses 

prepared for this EIS, and further confirmed through discussions with the environmental 

professionals who prepared these sections, no significant adverse impacts are expected as a 

result of implementing the alternatives after proposed mitigation measures are implemented. 

Consequently, none of the impacts of the vicinity of the Plan Area can be described as high 

and adverse in the context of EO 12898. Because no high and adverse impacts expected as a 

result of implementing the alternatives, no high and adverse human health or environmental 

effects of the alternatives are expected to affect minority or low-income populations 

disproportionately to the general population. The alternatives are considered to be consistent 

with the policy established in EO 12898.

Mitigation

None identified.

Cumulative Effects

None identified.
302

4.6 Land Use and Land Ownership

Introduction

Land use impacts are evaluated in terms of the potential effects of enactment of the 

alternatives, including the No Action Alternative, on existing and planned land uses in the 

vicinity of the Plan Area based on the following inconsistency with applicable land use plans 

and policies and incompatibility with existing land uses in the vicinity of the Plan Area.

Land management practices exercised by the BLM, including those in the Plan Area, must be 

consistent with the FLPMA, as well as other management guidelines and plans that provide 

for and direct the avoidance of land use conflicts where ever possible. It is therefore 

assumed that, per these guidelines, review and approval procedures for specific actions under 

these alternatives would result in avoidance or reduction of potentially adverse land use 

impacts. 

As described in Chapter 2, all the alternatives with the exception of the No Action 

Alternative incorporate the designation of eight management areas within the ISDRA, and 

the one-mile perimeter area surrounding the Recreation Area (the Planning Area). Impacts of 

the subsequent management measures unique to each of the areas, as they pertain to the 

individual action alternatives, are described below. 

From the point of view of the Purpose and Need of updating a recreation area management 

plan, it is important to note that rights-of-way and other entitlements relate to recreational 

activities in two ways. They are either (1) obvious and therefore avoided by OHV 

enthusiasts (e.g., railroads, roadways, transmission lines) or (2) unobtrusive and therefore 

with no or minor effects on recreational use (e.g., buried utilities). Therefore, in either case, 

impacts to recreational uses are negligible.

Impacts

Alternative 1

Under Alternative 1, land use management within the ISDRA would continue to be 

according to the existing and approved management 1987 Recreation Area Management 

Plan, as well as updated regulations that would constrain full implementation of the 1987 

RAMP (e.g., new facilities would not be allowed in the North Algodones Dunes Wilderness 

Area). The management areas common to the action alternatives would not be designated, 

and associated management actions would not be pursued. Because current practices would 

continue, this alternative would change land uses only to the extent dictated by the 1987 

RAMP. Impacts of these changes on applicable land use plans and policies and existing land 

uses within the ISDRA are discussed below.

Consistency With Land Use Plans and Policies

Under Alternative 1, the ISDRA would continue to be managed for multiple uses, including 

recreation and resource protection, as specified in the CDCA Plan and in accordance with 

other applicable guidelines. No new management areas and associated ROS classes would 
303

be designated. The CDPA of 1994 established the approximately 26,202 acre North 

Algodones Dunes Wilderness, located in the northern portion of the Plan Area. Alternative 1 

would result in no change in the management of this area to maintain its wilderness status, as 

provided for in the CDPA. No land use or zoning changes are proposed for private and other 

lands not managed by the BLM in the Plan Area under this alternative. Alternative 1 would 

be consistent with the FLPMA, CDPA, CDCA Plan, and Imperial County General Plan and 

Zoning Regulations. However, implementation of the No Action Alternative would be 

inconsistent with applicable BLM recreation area management policies that call for periodic 

updates of management plans so that management practices can adapt to changing land use 

patterns and intensity.

Compatibility with Existing Land Uses

Under Alternative 1, non-recreational land uses would likely remain unchanged. The 

management agreements of the BLM with Bureau of Reclamation and the U.S. Navy would 

not change. BLM would continue to administer sand and gravel sales, geothermal leases, and 

oil and gas leases based on the concept of multiple use. Rights-of-way would be maintained 

consistent with current policies, and new rights-of-way would be granted subject to 

environmental review and compatibility with existing land uses. 

The geographic distribution of recreational and non-recreational land uses at the ISDRA 

would be the same under Alternative 1 as under current conditions, and all currently allowed 

use types would continue to be permitted. The BLM would continue to manage the 

Recreation Area for multiple uses, including recreation and resource protection. Therefore,

land uses under Alternative 1 would be compatible with existing land uses; and no adverse 

impacts are anticipated.

Alternative 2

The management emphasis of Alternative 2 is to assure continued use of the ISDRA for 

motorized and non-motorized recreational opportunities, and to provide for the protection of 

natural and cultural resources. The impacts of changes to applicable land use plans and 

policies consequent to the enactment of Alternative 2, as well as impacts to existing and 

future land uses at the ISDRA are discussed below.

Consistency With Land Use Plans and Policies

Under Alternative 2, management areas and associated ROS classifications would be 

established within the ISDRA that would accommodate both recreational opportunities, 

including motorized recreation, as well as the protection of biotic and cultural resources. The 

incorporation of multiple-use management measures for the ISDRA for this alternative 

would be consistent with FLPMA as well as specific recreation area management guidelines.

Changes to the MUC designations established by the CDCA Plan would occur under 

implementation of this alternative. Proposed management area and ROS class designations 

would not be consistent with allowable use under the existing MUCs with regard to the 

proposed type and intensity of recreational activities and the preservation of the character of 

the landscape. Therefore, Alternative 2 would be require an amendment to the CDCA Plan. 
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No land use or zoning changes are proposed for private and non-BLM lands in the Plan Area. 

Alternative 2 recreation and resource protection objectives are in conformance with the 

respective goals and objectives set forth in both the Land Use Element and the Conservation 

and Open Space Element of the Imperial County General Plan. The County also has zoned 

the entire ISDRA as S-Open Space, which permits multiple uses consistent with the 

Conservation and Open Space Element of the General Plan. Therefore, this alternative is 

consistent with the Imperial County General Plan and Zoning Regulations. 

Under Alternative 2, the North Algodones Dunes Wilderness Area would continue to be 

managed to maintain its wilderness values, as provided for in the CDPA. Therefore, this 

alternative would be consistent with the CDPA. Alternative 2 also would be consistent with 

FLPMA, the CDCA Plan, and Imperial County General Plan and Zoning Regulations. 

Implementation of this alternative would be consistent with applicable land use plans and 

policies.

Compatibility with Existing Land Uses

Alternative 2 would not result in changes to existing land use patterns in the ISDRA; and the 

BLM would continue to manage the ISDRA for multiple uses, including recreation and 

resource protection. The management agreements of the BLM with BOR and the U.S. Navy 

would not change. BLM would continue to administer sand and gravel sales, geothermal 

leases, and oil and gas leases based on the concept of multiple use. Such leases would 

potentially be granted within lands that are currently subject to interim closure.

The geographic distribution of recreational and non-recreational uses at the ISDRA would be 

the same under Alternative 2 as compared to the baseline. Overall, proposed land uses under 

Alternative 2 would be compatible with existing and future land uses; no land use 

compatibility impacts would result from implementation of this alternative.

Alternative 3

The goal of Alternative 3 is to implement an adaptive management strategy designed to 

optimize the protection of habitats and populations of sensitive species, while providing 

opportunities for continued OHV access and other recreational activities within the Plan 

Area. The effect of the enactment of Alternative 3 on applicable land use plans and policies, 

as well as existing and future land uses within the Plan Area, is discussed below.

Consistency with Land Use Plans and Policies

Under Alternative 3, management areas and associated ROS classes would be designated 

within the ISDRA that would be generally more restrictive to OHV recreational activities. 

However, the ISDRA would continue to be managed for multiple uses, including recreation. 

Based on the concept of multiple use, this alternative would be consistent with the FLPMA.

Because OHV use in certain areas within the ISDRA would not be allowed under this 

alternative, the proposed management area and ROS class designations would be inconsistent 

with the permitted uses of the CDCA Plan for the ISDRA, as indicated by the MUC 

classification system. This alternative would require an amendment to the CDCA Plan.
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No land use or zoning changes are proposed for private and other lands not managed by the 

BLM in the Plan Area. Alternative 3 would increase the protections provided to the North 

Algodones Dunes Wilderness Area by placing more restrictive ROS classifications on 

surrounding management areas. Therefore, this alternative would be consistent with the 

CDPA. Implementation of this alternative would be consistent with the FLPMA, CDPA, 

CDCA Plan, and Imperial County General Plan and Zoning Regulations. However, it would 

be inconsistent with the CDCA Plan unless it was amended by this action.

Compatibility with Existing Land Uses

Alternative 3 would result in the closure of some ISDRA areas to motorized recreation and 

limit the intensity level of OHV use in other areas as compared to the baseline. These land 

use changes would be compatible with surrounding land uses in the ISDRA as non-motorized 

recreational land uses would continue in these areas, motorized recreation would continue in 

other ISDRA areas, and natural and cultural resources would be afforded maximum levels of 

protection. Therefore, under Alternative 3, the BLM would continue to manage the ISDRA 

for multiple uses, including recreation and resource protection. 

The management agreements of the BLM with the BOR and the U.S. Navy would not 

change. The BLM would continue to administer sand and gravel sales, geothermal leases, 

and oil and gas leases based on the concept of multiple uses, although leases would likely not 

be granted on areas permanently closed to vehicles.

While the geographic distribution of recreational and non-recreational uses at the ISDRA 

would change under Alternative 3 as compared to the baseline, all currently allowed use 

types would continue to be permitted. The BLM would continue to manage the ISDRA for 

multiple uses, including recreation and resource protection. Therefore, proposed uses under 

Alternative 3 would be compatible with existing and future land uses; and no land use 

compatibility impacts are anticipated from implementation of this alternative.

Alternative 4

The goal of Alternative 4 is to maximize motorized recreational opportunities within the 

ISDRA consistent with public scoping comments that had this as a priority. The effect of 

these changes, as compared to the baseline, on applicable land use plans and policies and 

existing and future land uses at the ISDRA is discussed below.

Consistency with Land Use Plans and Policies

Under Alternative 4, management areas and associated ROS classes would be designated 

within the ISDRA that maximize motorized recreational opportunities. The ISDRA would 

continue to be managed for multiple uses, including resource protection. Consequently, this 

alternative would be consistent with the FLPMA.

Because the intensity of OHV use in certain areas within the ISDRA would increase under 

this alternative, the proposed management area ROS class designations under this alternative 

would be inconsistent with the CDCA Plan uses for the ISDRA, as indicated by the MUC 

system. This plan would amend the CDCA Plan.
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No land use or zoning changes are proposed for private and other lands not managed by the 

BLM in the Plan Area. Alternative 4 management measures are in conformance with the 

respective goals and objectives set forth in both the Land Use Element and the Conservation 

and Open Space Element of the Imperial County General Plan. The County also has zoned 

the entire ISDRA as S-Open Space, which permits multiple uses consistent with the 

Conservation and Open Space Element of the General Plan. Therefore, this alternative is 

consistent with the Imperial County General Plan and Zoning Regulations. 

The CDPA of 1994 established the approximately 26,202-acre North Algodones Dunes 

Wilderness, located north of SR-78 and south of the Mammoth Wash Management Area. 

Enactment of Alternative 4 would not modify or minimize the protections provided to this 

wilderness as provided in the CDPA. Therefore, this alternative would be consistent with the 

CDPA. 

Compatibility with Existing Land Uses

Although Alternative 4 would result in an increased intensity of motorized recreational use 

within the ISDRA as compared to the baseline, this alternative would be compatible with 

existing and planned land uses in the ISDRA. Motorized and non-motorized recreational 

land uses would continue. In addition, the management actions that apply to all alternatives, 

including the public relations, law enforcement, and adaptive management programs, would 

encourage protection for natural and cultural land uses by reducing the incidence of 

encroachment of intensive recreation activity to adjacent areas. 

Non-recreational land uses would remain unchanged as a result of implementing Alternative 

4. Management agreements of the BLM with the BOR and the U.S. Navy would not change. 

BLM would continue to administer sand and gravel sales, geothermal leases, and oil and gas 

leases based on the concept of multiple use, and leases would potentially be granted within 

lands that are currently subject to interim closure.

While the geographic distribution of recreational land uses at the ISDRA would change 

under Alternative 4 as compared to the baseline, all currently allowed use types would 

continue to be permitted. Therefore, proposed uses under Alternative 4 would be compatible 

with existing and anticipated future land uses; and no land use impacts are anticipated from 

implementation of this alternative.

Mitigation Measures

No adverse impacts were identified that would require mitigation measures for any project 

alternative.
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Cumulative Effects

BLM has recently revised several plans. Each of these plans amended the CDCA Plan. 

Together these plans change the land use in the California Desert District. The acreages 

allotted to each multiple land use classification changed. 

NECO is intended to protect and conserve natural resources, providing in particular for the 

recovery of the desert tortoise, while simultaneously balancing human uses of the Colorado 

portion of the Sonoran Desert ecosystem. The planning area for NECO comprises more than 

5.5 million acres and is bordered along the southwest by the ISDRA. The land affected 

includes the northern and eastern Colorado Desert and the eastern half of Joshua Tree 

National Park. 

BLM is the lead agency for plan development, with cooperation from NPS, the US Marine 

Corps (USMC), USGS, USFWS, CDFG, Imperial County, and Riverside County. The 

management plan would become a binding plan for BLM, NPS, and the CMAGR. BLM 

recently signed a record of decision for the NECO Plan.

Implementation of NECO would amend the CDCA Plan and would result in beneficial 

impacts to biological resources in the desert Southwest. NECO could result in reduced 

motorized vehicle access within its planning area, as well as the closing of some desert 

washes in the western part of Riverside County and two small OHV areas. Few people 

currently visit the OHV areas proposed to be closed (Ford Dry Lake, which is 1,134 acres, 

and Rice Valley Dunes, which is 2,790 acres) (Crowe, 2002).

The purpose of the West Mojave Habitat Conservation Plan (West Mojave Plan) is to 

conserve and protect the desert tortoise and nearly 100 other sensitive plants and animals, as 

well as the ecosystems on which they depend. The 9.4 million-acre planning area 

encompasses most of California's western Mojave Desert. It extends from Olancha in Inyo 

County on the north to the San Gabriel and San Bernardino Mountains on the south, and 

from the Antelope Valley on the west to the Mojave National Preserve on the east. About one 

third of the planning area is private land, approximately one third is within military 

reservations, and the remainder consists of public lands managed by BLM.

BLM is the lead agency for preparation of a DEIS for the draft West Mojave Plan. The DEIS 

is anticipated to be released in mid-2003. Implementation of the West Mojave Plan could 

result in beneficial impacts to biological resources in the western Mojave Desert. Depending 

on the alternative selected, the West Mojave Plan could result in reduced motorized vehicle 

access within its planning area and increased management of existing OHV areas (Pilmer, 

2002).

The draft Northern and Eastern Mojave Plan (NEMO Plan) includes management actions to 

protect threatened, endangered, and sensitive species and habitats on federal lands 

administered by the BLM in the eastern Mojave Desert. The NEMO Plan may amend the 
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CDCA Plan. The NEMO Plan area encompasses about 2.4 million acres of public lands in 

eastern San Bernardino and Inyo Counties of California.

BLM is the lead agency for completion of the NEMO Plan and consequent CDCA Plan 

Amendments. A record of decision was recently signed for this plan. (However, an 

additional plan will be completed to designate routes.) The EIS for this project analyzes 

potential impacts from the implementation of the proposed MUCs for the lands released from 

wilderness consideration by enactment of the CDPA, route designation in some areas, a 

proposed strategy to accomplish route designation in the remainder of the planning area, and 

proposed MUC changes to eliminate landfills on public lands.

Implementation of the NEMO Plan could result in beneficial impacts to biological resources 

in the NEMO planning area. Depending on the alternative selected, the NEMO Plan could 

result in reduced motorized vehicle access within its planning area and increased 

management of existing OHV areas (BLM, 2002). The NEMO Plan, however, does not 

propose increased management of Dumont Dunes, which offers a similar semi-primitive 

motorized OHV experience as the ISDRA (although Dumont Dunes is significantly smaller 

than the ISDRA) (Aarons, 2002). Dumont Dunes is located approximately 30 miles north of 

Baker on SR-127, off Dumont Dunes Road. It is approximately 275 miles northeast of the 

ISDRA.

WECO ROT is a BLM project to develop a transportation network in the Imperial Valley. 

Its action is limited to designation of existing routes of travel and camping areas; multiple 

use classifications will not be changed in this project. Implementation of the WECO ROT 

plan could result in beneficial impacts to biological resources in the WECO ROT planning 

area. WECO ROT Plan could result in reduced motorized vehicle access through the closure 

of some routes and limitations (vehicle/seasonal) on other routes.

The Gateway of the Americas Specific Plan Area (Gateway) is a 1,775-acre master-planned 

industrial and commercial complex owned by private parties and federal, state, and local 

agencies. Retail shopping, business offices, and lodging would be developed in response to 

the traffic from the Port of Entry. Cumulative effects relate to the loss of undeveloped rural 

land and the development of rural land into industrial, commercial, and transportation-related 

services. Imperial County prepared the Final EIR for the Gateway Specific Plan in 1997

(Imperial County Planning Department, 1997). The project is in various stages of 

development in the initial construction phase (Phase 1). Phase 2 is expected to continue for 

20 to 40 years (IID and BOR, 2002).
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4.7 Visual Resources

All land-disturbing activities have a direct effect on the visual resource. These effects can be 

either positive or negative, depending on the location, size, color, and viewing location. 

Generally speaking, alternatives with high levels of recreation development have the highest 

potential for decreasing scenic quality. Ground-disturbing activities like road and facilities 

construction have the potential of not harmonizing with the natural character of the 

landscape. Dispersed camping opportunities also have the potential to degrade the landscape, 

but to a much lesser degree. 

Alternatives that prescribe management for vegetation and wildlife habitat would have little 

direct effect on visual resources. In addition, alternatives that remove non-native and other 

encroaching vegetation would increase the visual variety of a landscape. 

Alternatives in which people are encouraged to gather in certain areas have an indirect effect 

on the visual resource. Vegetation can be trampled, user-built trails tend to appear, and litter 

detracts from the naturalness of the landscape.

Assumptions and Assessment Guidelines

Visual Resource Management classes have been provided for purposes of comparison only to 

provide a context of potential changes that could occur to the visual landscape. Adverse 

impacts on the visual resources of the ISDRA would result if the following conditions exist:

Development proposed as part of an alternative would substantially alter the undisturbed 

character of the ISDRA landscape, or would be out of character with the landscape.

View opportunities from established lookouts (e.g., Osborne Lookout or Mesquite Mine 

Lookout) are obstructed or eliminated. View opportunities from known popular areas (other 

than lookouts) are obstructed or eliminated.

Impacts

Alternative 1

This alternative would not affect the current status of the North Algodones Dunes Wilderness 

Area, which prohibits motorized use within its boundaries, but allows non-motorized 

recreation use.

It is expected that recreationists would continue to congregate at the popular areas during 

peak-use times (e.g., major holiday weekends). Due to anticipated increases in visitation, the 

visual resources of the landscape during peak periods would appear more crowded at the 

popular areas when compared to baseline conditions. These additional visitors during peakuse periods will result in temporary (episodic) landscape changes. When the peak-use periods 

end, use levels and associated visual resources would return to a condition that is similar to 

the baseline condition. This episodic change in visual resources is not considered an adverse 

impact.
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Evaluating this alternative in the context of the VRM classes depicted in Figure 3.7-1 

indicates that the level of existing development associated with this alternative is generally 

consistent with the associated VRM classes.

Alternative 2

Change in ROS Designation

When compared to the baseline condition, the ROS associated with this alternative would 

allow changes in recreation use, in terms of intensity of use, type of use allowed (motorized 

versus non-motorized), and level of facility development. Implementation of this alternative 

would allow more intense use in the following areas, when compared to the baseline 

condition: 

Ogilby Management Area

Implementation of this alternative would allow similar use in the following areas, when 

compared to the baseline condition:

Adaptive Management Area

Dune Buggy Management Area

Gecko Management Area

Glamis Management Area

Buttercup Management Area

North Algodones Dunes Wilderness Area 

Implementation of this alternative would allow a less intense level of use in the following 

areas, when compared to the baseline condition:

Mammoth Wash Management Area

From a visual resources perspective, allowing more intense use in a management area would 

change the landscape during periods of peak use. Views of areas during peak use periods 

from the air or from higher elevations atop the dunes provide a very different image than 

views of the same areas during mid-week periods. This short-term change in landscape is 

adverse, but is not considered significant. This conclusion is based in part on the fact that 

recreationists visiting ISDRA during peak-use periods have the expectation of seeing crowds.

Allowing more intense use in a particular management area provides views of the inner 

dunes to more recreationists at one time. This is a visual benefit to the public. Conversely, 

allowing less intense use in a particular management area provides views of the inner dunes 

to fewer recreationists at one time. Due to the high level of mobility of the recreationists 

using the dunes, a lower level of allowable use would not adversely affect view opportunities 

of the OHV enthusiasts.

This alternative would also include updating the kiosks at the Wildlife Viewing Area. This 

would enhance the viewing experience of visitors and is considered a beneficial impact.

A ranger station would be constructed at Cahuilla and Buttercup. This would not alter views 

from Osborne Overlook. 
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Applying a dust palliative on the Wash Road has the potential to reduce the dust and, 

therefore, increase visibility during windy or higher use days. This would result in a visual 

benefit to the public.

This alternative would provide for the development of pit toilet facilities in Glamis Flats, The 

Washes, and Dune Buggy Flats areas. This would result in the introduction of structures 

where they currently do not exist. This would be considered an adverse visual impact.

Potentially closing Oldsmobile Hill, Competition Hill, Test Hill, and Patton Valley at night 

would result in those areas appearing darker at night (less nighttime glow) due to the 

elimination of vehicle lights.

In the Buttercup Management Area, several changes to the landscape would occur. 

Interpretive facilities and parking would be developed near Grays Well Road, a law 

enforcement facility would be constructed, and camping sites could be designated. These 

facilities would change the character to a more developed area; however, a rural ROS 

designation would allow such changes, and such development would be consistent with the 

associated VRM Class 4.

Evaluating this alternative in the context of the VRM classes depicted in Figure 3.8-1 

indicates that the level of existing development associated with this alternative is generally 

consistent with the associated VRM classes.

Change in Visitation

Visitation is expected to increase over the years; therefore, the concentration of users is also 

expected to increase. In addition, more concentrated use would be allowed in certain areas of 

the ISDRA with implementation of this alternative. These additional visitors during peakuse periods will result in temporary (episodic) landscape changes. When the peak-use periods 

end, use levels and associated visual resources would return to a condition that is similar to 

the baseline condition. This episodic change in visual resources is not considered an adverse 

impact because it would be temporary in nature.

Alternative 3

Change in ROS Designation

When compared to the baseline condition, the ROS associated with this alternative would 

affect the intensity of recreation use and the level of facility development.

Implementation of this alternative would allow the same intensity of use in the following 

areas, when compared to the baseline condition:

Gecko Management Area

Dune Buggy Flats Management Area

North Algodones Dunes Wilderness

Ogilby Management Area
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Implementation of this alternative would allow less intense use in the following areas, when 

compared to the baseline condition:

Adaptive Management Area, including not allowing motorized vehicles.

Mammoth Wash Management Area, including not allowing motorized vehicles.

Buttercup Management Area

Glamis Management Area

Allowing less intense use in a particular management area provides views of the inner dunes 

to fewer recreationists at one time. Due to the high level of mobility of the recreationists 

using the dunes, a lower level of allowable use would not adversely affect view opportunities 

of the OHV enthusiasts.

This alternative would also include updating the kiosks at the Wildlife Viewing Area. This 

would enhance the viewing experience of visitors and is considered a beneficial impact.

Applying a dust palliative on the Wash Road has the potential to reduce the dust and, 

therefore, increase visibility during windy or higher use days. This would result in a visual 

benefit to the public.

This alternative would provide for the development of pit toilet facilities in Glamis Flats, The 

Washes, and Dune Buggy Flats areas. This would result in impacts similar to those described 

above under Alternative 2. 

Potentially closing Oldsmobile Hill, Competition Hill, Test Hill, and Patton Valley at night 

would result in those areas appearing darker at night (less nighttime glow) due to the

elimination of vehicle lights.

A ranger station would be constructed at Osborne Overlook. This would alter views from 

this location.

In the Buttercup Management Area, several changes to the landscape would occur. 

Interpretive facilities and parking would be developed near Grays Well Road, and a law 

enforcement facility would be constructed. These facilities would change the character to a 

more developed area; however, a roaded natural ROS designation would allow such changes, 

and such development would be consistent with the associated VRM Class 3.

Evaluating this alternative in the context of the VRM classes depicted in Figure 3.7-1 

indicates that the level of existing development associated with this alternative is generally 

consistent with the associated VRM classes.

Change in Visitation

Visitation is expected to increase over the years; therefore, the concentration of users is also 

expected to increase. However, lower levels of use and development would be allowed in 

certain areas of the ISDRA with implementation of this alternative. Additional visitors 

resulting from future growth in attendance during peak-use periods will result in temporary 

(episodic) landscape changes. When the peak-use periods end, use levels and associated 
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visual resources would return to a condition that is similar to the baseline condition. This 

episodic change in visual resources is not considered an adverse impact because it would be 

temporary in nature.

Alternative 4

Change in ROS Designation

When compared to the baseline condition, the ROS associated with this alternative would 

affect the intensity of recreation use and the level of facility development. Implementation of 

this alternative would allow more intense use in the following areas, when compared to the 

baseline condition:

Dune Buggy Management Area

Adaptive Management Area.

Ogilby Management Area

Gecko Management Area

Glamis Management Area

Implementation of this alternative would allow the same use in the following areas, when 

compared to the baseline condition:

North Algodones Dunes Wilderness Area

Buttercup Management Area

Implementation of this alternative would allow less intense use in the following areas, when 

compared to the baseline condition:

Mammoth Wash Management Area

From a visual resources perspective, allowing more intense use in a management area would 

change the landscape during periods of peak use. Views of areas during peak-use periods 

from the air or from higher elevations atop the dunes provide a very different image than 

views of the same areas during mid-week periods. This short-term change in landscape is 

adverse, but is not considered significant. This conclusion is based in part on the fact that 

recreationists visiting ISDRA during peak-use periods have the expectation of seeing crowds.

Allowing more intense use in a particular management area provides views of the inner 

dunes to more recreationists at one time. This is a visual benefit to the public. Conversely, 

allowing less intense use in a particular management area provides views of the inner dunes 

to fewer recreationists at one time. Due to the high level of mobility of the recreationists 

using the dunes, a lower level of allowable use would not adversely affect view opportunities 

of the OHV enthusiasts.

The impacts associated with the construction of a ranger station at Cahuilla would be the 

same as the impact discussed previously under Alternative 2. The additional facilities 

planned in the Glamis Management Area would also result in similar impacts as 
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Alternative 2, but would be marginally greater due to the increased level of facility 

development provided under this alternative. 

Applying a dust palliative on the Wash Road has the potential to reduce the dust and, 

therefore, increase visibility during windy or higher use days. This would result in a visual 

benefit to the public.

Potentially closing Oldsmobile Hill, Competition Hill, Test Hill, and Patton Valley at night 

would result in those areas appearing darker at night (less nighttime glow) due to the 

elimination of vehicle lights.

In the Buttercup Management Area, several changes to the landscape would occur. 

Interpretive facilities and parking would be developed near Grays Well Road, camping sites 

would be designated, and a law enforcement facility would be constructed. These facilities 

would change the character to a more developed area; however, an urban ROS designation 

would allow such changes, and such development would be consistent with the associated 

VRM Class 4.

Evaluating this alternative in the context of the VRM classes depicted in Figure 3.7-1 

indicates that the level of existing development associated with this alternative is generally 

consistent with the associated VRM classes.

Change in Visitation

Visitation is expected to increase over the years; therefore, the concentration of users is also 

expected to increase. In addition, more concentrated use would be allowed in certain areas of 

the ISDRA with implementation of this alternative. Additional visitors during peak-use 

periods will result in temporary (episodic) landscape changes. When the peak-use periods 

end, use levels and associated visual resources would return to a condition that is similar to 

the baseline condition. This episodic change in visual resources is not considered an adverse 

impact because it would be temporary in nature.

Mitigation Measures

The following measures should be applied to all new facilities and physical improvements in 

the ISDRA to ensure they harmonize with the natural landscape. The degree to which an 

activity harmonizes with the landscape is based on whether its form, line, color, and texture 

replicate those of the existing landscape. 

Within the North Algodones Dunes Wilderness Areas, no improvements to roadways, new 

interpretive signs and kiosks, or establishment of vendor areas should occur in this VRM 

Class 1 area.

When updating the kiosks near the Wildlife Viewing Area in the VRM Class 1 area (near the 

North Algodones Dunes Wilderness Area) and in developing and constructing the new ranger 

stations, use materials that harmonize with the natural landscape.
315

Additional interpretive signs, kiosks, and vendor areas should occur in VRM Class 3 or 4 

areas only. By definition, interpretive signs, kiosks, and vendor areas should attract 

attention; therefore, they should not be developed in Class 1 or 2 areas.

Cumulative Effects

The U.S. Border Patrol has placed numerous tools in the ISDRA to assist in apprehending 

undocumented immigrants and smugglers. These tools include barriers, shade structures and 

cameras. These items and the associated Border Patrol activities can have a cumulative 

effect on visual resources.

Several utility corridors exist in the ISDRA; they too, can have a negative cumulative effect 

on the visual landscape.
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4.8 Water Resources

Assumptions and Assessment Guidelines

The assessment of impacts assumes that implementation of the project alternatives will 

include measures required by federal, state, or local law and/or regulation, if applicable. The 

project alternatives would have an adverse impact on water resources if it would:

Substantially degrade water quality

Contaminate a public water supply

Cause substantial flooding or siltation

Substantially alter surface flow conditions, patterns, or rates

Result in water demands that would outstrip supply

The All American Canal, the New Coachella Canal, and ephemeral surface flows are the only 

surface waters in the project vicinity that have the potential to be affected by planned 

activities under this alternative. The majority of ephemeral surface flows are located in the 

eastern portion of the Plan Area.

Some of the OHVs at the ISDRA are expected to leak minor amounts of petroleum products 

in the normal course of operations. Small amounts of oil and fuel may be spilled or leaked 

onto the ground surface while refueling OHVs. Although such leakage is considered an 

adverse consequence of OHV use, it is not expected to affect groundwater quality. This is 

because leakage would be minor on an individual basis and, as a whole, would occur in a 

dispersed manner that corresponds to the OHV usage areas in the ISDRA. The potential for 

oil, grease, and fuel leakage to actually reach groundwater is extremely remote due to the low 

rainfall levels in the project area, the great depth to groundwater, and the volatile nature of 

fuel.

The chief impacts on water resources resulting from enactment of any of the alternatives 

would be to increase or decrease water supply demand by visitors to the ISDRA. However, 

visitors bring their own water supply to the ISDRA. There is no water available for public 

use at the ISDRA. Current as well as projected future visitor use levels under any of the 

alternative scenarios would result in water-use rates that fall well under the available water 

supply. (Please note that the water supply used by the visitors is from the visitor’s home 

area, or purchased through vendors or stores, typically in the local community surrounding 

the ISDRA. It is not supplied by BLM at the ISDRA.) 

The Plan Area is not an area of groundwater recharge, nor would any of the alternatives 

affect groundwater quality of supplies.
317

Impacts

Alternative 1

Surface Water Impacts

Impacts to surface waters under Alternative 1 would be negligible. Therefore, significant 

adverse impacts to surface waters are not anticipated. 

Groundwater Impacts

Negligible impacts to groundwater are anticipated under this alternative. Significant adverse 

impacts would not occur.

Wildlife Guzzler Impacts

Wildlife guzzlers are clearly marked. Potential impacts to the wildlife guzzlers in the 

Mammoth Wash Management Area and the North Algodones Dune Wilderness Area would 

be somewhat greater than under the action alternatives due to the lack of management 

responses to increased visitor use entailed by the No Action Alternative.

Alternative 2

Surface Water Impacts

Negligible increases in impermeable surface would result from limited facility development 

and road improvements. However, no change in the potential for storm water runoff to reach 

the All American Canal or the New Coachella Canal would result; runoff would continue to 

infiltrate into the surrounding sands and soil rather than flow to the canals. Impacts from 

OHV activities would be marginally greater than Alternative 3 due to a larger area open to 

OHV use and higher visitor use. Impacts would be less than under Alternative 4 due to less 

OHV acreage and lower intensity of use. Therefore, impacts to surface waters under this 

alternative would be negligible. Significant adverse impacts to surface water would not 

result from implementation of this alternative.

Groundwater Impacts

Impacts to groundwater under this alternative would be negligible. Significant adverse 

impacts to the groundwater would not result from implementation of this alternative.

Wildlife Guzzler Impacts

As noted above, wildlife guzzlers are clearly marked. The potential for impacts to the 

wildlife guzzlers in the Mammoth Wash Management Area and the North Algodones Dune 

Wilderness Area would be less under this alternative due the application of appropriate 

management procedures accompanying increased visitor use.

Alternative 3

Surface Water Impacts

Negligible increase in impermeable surface would result because of limited facility 

development and no road improvements are proposed under this alternative. No change in 

the potential for storm water runoff to reach the All American Canal or the New Coachella 

Canal would result; runoff would continue to infiltrate into the surrounding sands and soil 
318

rather than flow into the canals. Therefore, no impacts to surface water are anticipated from 

this alternative.

Groundwater Impacts

The majority of OHV use under this alternative would occur in the area south of SR-78 

(including along Gecko Road) and in the vicinity of I-8. 

Further, implementation of this alternative would not result in a substantial change from 

existing conditions. Significant adverse impacts to groundwater quality are not anticipated 

and mitigation is not proposed.

Wildlife Guzzler Impacts

Under Alternative 3, the wildlife guzzlers would not be affected by OHV use because the 

areas where the guzzlers are located (Mammoth Wash Management Area and the North 

Algodones Dunes Wilderness Area) would be closed to OHV use. No adverse impacts to 

guzzlers would occur under this alternative.

Alternative 4

Surface Water Impacts

Under this alternative, proposed facility developments and road improvements would 

increase the area of impermeable surfaces in the Plan Area. However, due to the extremely 

small scale of these improvements compared to the 159,000 acre ISDRA, as well as the 

location of the improvements relative to ephemeral surface waters, the potential for 

substantially increased runoff or degraded water quality is considered negligible. Significant 

impacts to surface water quality are not anticipated.

Groundwater Impacts

Impacts to groundwater under this alternative would be negligible because the increased area 

open to OHV use and the increased level of intensity are not expected to exceed a threshold 

beyond which percolation of fuel or oil would be expected to occur to the water table. 

Therefore impacts, including significant adverse impacts, to groundwater would not occur.

Wildlife Guzzler Impacts

The enactment of Alternative 4 would not affect the wildlife guzzlers in the North Algodones 

Dunes Wilderness Area because that area will remain closed to OHV use under this 

alternative. The two guzzlers in the Mammoth Wash Management Area are within areas 

designated open for OHV use under this alternative, but are clearly marked. Typically, OHV 

users avoid structures and areas of high plant growth. Any substantial disturbance of the 

guzzler area would be considered an adverse impact.

Mitigation Measures

To avoid potential adverse impacts to the two wildlife guzzlers in the Mammoth Wash 

Management Area, the area in the immediate vicinity of the guzzlers could be closed to OHV 

use. This type of mitigation measure would be expected to prevent any adverse impact to the 

wildlife guzzlers in the Mammoth Wash Management Area. 
319

Cumula tive Effects

None identified.
320

 4.9 Cultural Resources

Assumptions and Assessment Guidelines

Direct impacts on cultural resources are typically related to the level of ground disturbance 

associated with a project. Ground disturbance, whether for facilities improvements or other 

activities, is the primary factor affecting archaeological sites and sites with Native American 

heritage values. Indirect impacts are less associated with the intentional changes being 

produced by the project. These can include such things as changes to or new travel access 

routes that lead to greater access to an area, thus increasing the potential for looting. 

Erosion-control measures that alter deposition patterns and lead to greater erosion or 

sedimentation can also indirectly affect cultural resources.

The following assumptions were made in determining impacts resulting from the Project 

Alternatives:

The current cultural resources database for the ISDRA is representative of the range 

of resources present.

Ground disturbance that affects cultural resources can cause irreversible damage to 

these nonrenewable resources.

Owing to the nature of shifting sands, and particularly their depth, regardless of the 

level of inventory, some resources may not be identified.

Greater access to an area through time means more opportunities for unauthorized 

collection and looting, as well as more ground disturbance.

Conversely, reduced access over time leads to reduced opportunities for unauthorized 

collection and looting, and reduced ground disturbance.

Employing these assumptions, and what is currently know of the cultural resources of the 

project area, extrapolations are made below regarding the extent of impact to cultural 

resources that would result from enactment of each of the project alternatives, including the 

No-Action Alternative. 

Impacts

Given the known cultural resources present in the ISDRA, all alternatives have the potential 

to affect resources that may qualify for the California Register of Historical Resources 

(CRHR) and the NRHP. The following discussion provides a ranking of the four project 

alternatives based on their potential for ground disturbance. Under this ranking, the 

assessment of the relative potential of an alternative to affect cultural resources is based on 

the premise that the greater the degree of access to OHV use and the greater the area of 
321

potential ground disturbance, the greater the potential for effects. Due to limitations in the 

existing data, this approach does not take into consideration resource significance, site type 

and complexity, or variations in resource densities. 

Alternative 1

Under Alternative 1, the degree of access and relative area of disturbance, and therefore 

potential for impacts, could be greater than Alternatives 2 and 3, but less than Alternative 4. 

Management measures currently in place could continue, such as public educational efforts 

that stress the importance of not disturbing cultural resources, and therefore some reduced 

impact to cultural resources would be expected, relative to Alternative 4, below.

Alternative 2

Alternative 2 could result in a greater area of disturbance than Alternative 3, and, therefore, 

would have a higher potential for cultural resource impacts. However, Alternative 2 could 

result in a smaller area of disturbance than Alternatives 1 or 4 (see below) and, therefore, 

would have a lower potential for cultural resource impacts than these alternatives would.

Alternative 3

Enactment of Alternative 3 could result in the most restrictive measures being applied to 

OHV recreational activity in the ISDRA. Therefore, this alternative would have the least 

potential for ground disturbance, due to the minimal area open to OHV use, compared to the 

other project alternatives and existing conditions. Enactment of this alternative could also 

restrict access more than any other alternative, and therefore minimize the possibility of 

unauthorized collection of cultural resources. Therefore, impacts to cultural resources under 

this alternative would be less than all other alternatives.

Alternative 4

Enactment of this alternative could open portions of the ISDRA to the highest intensity of 

use (e.g., the Gecko and Buttercup Management Areas would receive a ROS classification of 

Urban), and open the widest area to OHV recreational activities, relative to other alternatives. 

Ground disturbing activities could therefore be more extensive and of higher intensity than 

any other alternative. In addition, the greater level of access would result in a higher 

frequency of unauthorized disturbance of cultural resources. Therefore, Alternative 4 could 

have greater impacts to cultural resources than any of the other alternatives. 

Mitigation Measures

National Register historic properties, the Plank Road and All American Canal, are within the 

dune system and the Coachella Canal is adjacent to the western edge of the dunes. None of 

these historic properties will be adversely affected by any of the alternatives to the plan, and 

alternative 2 benefits Plank Road by providing for additional protective measures, as 

identified in the RAMP. 

Any actions, which occur as a result of implementing this plan, will be reviewed in 

accordance with Section 106 of the National Historic Preservation Act and BLM’s Protocol 

Agreement.
322

Cumulative Effects

The U.S. Border Patrol has placed numerous tools in the ISDRA to assist in apprehending 

undocumented immigrants and smugglers. These tools include barriers, shade structures and 

cameras. These activities can have a cumulative effect on cultural resources as the tool and 

associated activities are ground disturbing.

Several utility corridors exist in the ISDRA; they too, can have a negative effect on the 

cultural resources due to their ground disturbing nature.

In addition, the ISDRA is a popular location for photography and filming. Both of these 

activities can have a negative effect on cultural resources due to their potential ground 

disturbing nature.
323

4.10 Transportation and Traffic

Assumptions and Assessment Guidelines

The analysis of potential traffic impact was prepared based on the Highway Capacity Manual

published by the Transportation Research Board of the National Research Council. In 

addition, the American State Highway and Transportation Officers’ Geometric Design of 

Highways and Streets was considered in determining impact significance. 

Impacts

Vehicular traffic generated by each alternative is directly proportional to the estimated visits. 

It is assumed that the average occupancy of vehicles is 3.5 persons per vehicle. Vehicle 

occupancy for recreational trips is typically higher than that of general traffic. The 

3.5 occupancy rate is based on the assumption of three or four occupants in the majority of 

vehicles and 0.5 percent tour bus use. Table 4.10-1 shows the baseline and projected future 

annual vehicular traffic for the four project alternatives. Future traffic is projected to the 

2012/2013 season, consistent with the assumption that the updated RAMP will be in place at 

least 10 years. The 2012/2013 traffic is based on the maximum annual growth rates noted 

previously in Table 4.1-1. 

Table 4.10-1. Project Generated Annual Vehicular Traffic

1999/2000 Baseline 2012/2013

Project Alternatives* Visits

Annual Vehicle 

Trips * Visits

Annual Vehicle 

Trips *

Alternative 1 867,753 495,860 2,071,000 1,183,430

Alternative 2 867,753 495,860 1,637,000 935,430

Alternative 3 867,753 495,860 1,488,000 850,290

Alternative 4 867,753 495,860 1,800,000 1,028,570

* Based on an average vehicle occupancy of 3.5

Annual traffic volume is only a general indicator of traffic impact. The most critical element 

in highway capacity and LOS is the peak-hour volume. Based on historical attendance 

estimates, peak traffic volumes would occur over the six major holiday weekends. 

Furthermore, for purposes of this analysis, it was assumed that the arrival peak is more 

critical than the departure peak, that the majority of the arrivals are concentrated in the first 

2 days, and that 60 percent arrive on the peak day. Due to the diverse origin of the arriving 

trips, it is conservative to assume that 20 percent of the peak-day traffic will be concentrated 

in the peak hour.

As noted previously in Section 3.10, the Thanksgiving weekend has historically been the 

most popular major holiday weekend, with approximately 12 percent of all annual visits. 

Therefore, the highest volumes of traffic are expected to occur during this period. Potential 

traffic impacts for each of the alternatives are discussed below, and are based on the worsecase scenario during the Thanksgiving holiday.
324

Alternative 1

As noted above under Table 4.10-1, the highest future (2012/2013 season) annual traffic 

volumes are projected to occur under Alternative 1. Table 4.10-2 shows the distribution of 

Alternative 1 peak-hour volumes on major highway segments providing access to the project 

sites during the Thanksgiving weekend.

Table 4.10-2. Peak Hour Traffic Distribution and LOS (Alternative 1)

Baseline 2012/2013

Access

% 

Distribution

Highest 

ISDRA 

Inbound 

Peak 

Hour

Peak 

Hour 

Inbound 

for 

ISDRA

Total 

Traffic*

Level 

of 

Service

Highest 

ISDRA 

Inbound 

Peak 

Hour

Peak 

Hour 

Inbound 

for 

ISDRA

Total 

Traffic*

Level 

of 

Service

I-8 

West 50 3,570 1,790 2,580 C 8,520 4,260 5,550 F

I-8 East 8 3,570 290 1,320 B 8,520 680 2,380 C

SR-78 

West 32 3,570 1,140 1,670 E 8,520 2,730 3,590 F

SR-78 

East 8 3,570 290 740 C 8,520 680 1,410 D-E

SR-98 

West 2 3,570 70 230 B 8,520 170 430 B

*One-way inbound for I-8, two-way for SR-78 and SR-98

For the highest peak hour on Thanksgiving weekend, SR-78 west of the project site will be

operating at LOS E in the baseline year and LOS F in 2012/2013. I-8 west will be operating 

at LOS F in 2012/2013. LOS E represents a condition near capacity or at capacity and LOS 

F is the operation condition where capacity is exceeded by demand and a slow moving queue 

begins to form.

The highest hourly volume of the year is not the criteria for highway design and acceptable

LOS. The Association of American State Highway and Transportation Officers (AASHTO)

recommends that the 30th highest hourly volume of the year be used as the design capacity of 

highways. However, for highways with unusual or highly seasonal fluctuation in traffic flow, 

the 30th hourly volume criterion may not be appropriate. The AASHTO Geometric Design 

of Highways and Streets states that economy dictates a design that results in somewhat less 

satisfactory traffic operation during seasonal peaks than on rural roads with normal 

fluctuation, and the public generally will accept such conditions. AASHTO further 

recommends that it may be desirable to choose an hourly volume for design, which is about 

50 percent of the volumes expected to occur during a very few maximum hours of the design 

year.

Based on the criteria of designing for 50 percent of the highest hourly volume, all segments 

of highways providing access to the project sites will be operating at LOS D or better. 

Further, the capacities of I-8 exit ramps will not be exceeded during the design peak hour 

assuming that the in-bound traffic will be distributed equally to the exits at Grays Well Road 
325

and Ogilby Road. Therefore, in the context of normal highway design practice, adverse 

traffic impacts during a few hours per year would not be considered significant. Adverse 

(though less than significant) impacts associated with future peak-hour project traffic during 

major holiday weekends would be mitigated through implementation of a Traffic Control 

Plan (TCP), as described below under the mitigation section.

Alternative 2

The high estimate for future visitation under Alternative 2 is approximately 20 percent less 

than the high range estimate under Alternative 1. Because traffic volumes are directly 

proportionate to visitation, future traffic trips to ISDRA under Alternative 2 would be 

approximately 20 percent less than under Alternative 1. Therefore, traffic impacts under this 

alternative would be less than under Alternative 1, and would not be significant. Similar to 

Alternative 1, potential adverse impacts associated with peak-hour holiday traffic will be 

mitigated through implementation of a TCP. 

Alternative 3

The high estimate for future visitation under Alternative 3 is approximately 30 percent less 

than the high range estimate under Alternative 1 and about 10 percent less than under 

Alternative 2. Because traffic volumes are directly proportionate to visitation, the future 

traffic trips to ISDRA under Alternative 3 would less than under Alternatives 1 and 2. 

Adverse impacts during the peak hour of major holiday weekends would be less under this 

alternative than under Alternatives 1 and 2, and would not be significant. Peak-hour impacts 

during major holiday weekends would be mitigated through implementation of a TCP.

Alternative 4

The high estimate for future visitation under Alternative 4 is approximately 15 percent less 

than the high range estimate under Alternative 1. Because traffic volumes are directly 

proportionate to visitation, future traffic trips to ISDRA under Alternative 4 would be less 

than under Alternative 1. Therefore, traffic impacts would not be significant. Future traffic 

volumes under Alternative 4 would be greater than under Alternatives 2 and 3 by 

approximately 10 and 20 percent, respectively. Therefore, impacts resulting from traffic 

under this alternative would also be greater than under Alternatives 1 and 2. Similar to 

Alternative 1, 2 and 3, adverse impacts during the peak hour of major holiday weekends 

would be mitigated through implementation of a TCP.

Mitigation

Developing a Special TCP could mitigate the traffic impacts caused by the few hours of 

exceptionally high hourly volumes. The TCP should include advance portable changeable 

message signs used on the freeway and local roads to provide motorist information and direct 

traffic to alternative exits. The TCP should include dispatching Rangers and California 

Highway Patrol officers to freeway exits and intersections along the access routes to direct 

traffic and provide quick response to traffic incidents.
326

Cumulative Effects

Border Patrol contributes to the traffic in the ISDRA Planning Area as a part of their 

apprehension of undocumented immigrants and smugglers.
327

4.11 Noise

Introduction 

Management actions for the entire ISDRA Plan Area (see Table 2.1) that would have the 

potential to result in increased noise exposure include:

Recreation – the level and locations of OHV activities within the management 

planning areas could determine the degree to which offsite locations or campgrounds 

may be exposed to noise generated from such activities.

Transportation/Traffic - grading and improvement of roads within the areas, 

potentially could result in increases in vehicular movements in some areas that would, 

in turn, cause elevated ambient noise levels.

Access and Facilities – development of new facilities in undeveloped areas would 

result in heightened human visitation and localized increases in ambient noise levels 

in such areas.

On the other hand, many management actions throughout the Plan Area could effectively 

control noise generated from activities in the management areas. Such actions include:

ROS classifications could eliminate or limit OHV activities within the management 

areas (e.g. semi primitive non-motorized areas such as the North Algodones Dunes 

Wilderness Management Area).

The adaptive management plan for biological resources could implement adaptive 

actions based on information gathered through scientific monitoring. Over time, the 

adaptive management actions could improve the environmental conditions for 

biological resources, including exposure to noise, where such measures are deemed 

necessary.

A number of public safety measures could have curbing effects on noise generated within the 

management areas. Such measures include law enforcement, posting of speed limits, and 

closure of certain areas from sundown to sunup.

Assumptions and Assessment Guidelines

The assessment of impacts assumes the implementation of measures required by federal, 

state, and local laws and regulations. Implementation of a project alternative would normally 

have an adverse noise impact if it would:

Substantially increase noise levels above the existing ambient noise levels at sensitive 

receptor sites (e.g., residences, schools, churches, hospitals)

Exceed local noise standards at sensitive receptor sites
328

Impacts are delineated as short-term construction noise or long-term operational noise. 

Impacts

Alternative 1

Under Alternative 1, the ISDRA would continue to be managed according to existing and 

approved management plans prescribed by the 1987 RAMP. All portions of the 1987 RAMP 

were not fully implemented and some may be implemented in the future. This may include 

facility development activities that would result in short-term construction noise. However, 

construction noise levels would be temporary and would not impact any noise-sensitive 

receptors. Significant noise impacts would not result.

Under Alternative 1, recreational usage (primarily OHV and camping) is expected to increase 

relative to baseline conditions. Consequently, background noise levels are expected to 

increase in usage areas. However, the increases in noise levels would not be significant 

because the ISDRA is remote; and there are no sensitive receptors in the vicinity. Although 

there are no limitations on OHV activity areas under Alternative 1, significant OHV noise 

impacts are not anticipated to occur.

Title 9, Chapter 2, Section 90702.00 of the Imperial County Ordinance defines noise level 

limits based on land use zones. The most stringent noise level criterion applied by the county 

is a nighttime limit of 45dBA hourly average noise level (Leq) for single-family residences. 

The County’s General Plan establishes a 60 dB Community Noise Equivalent Level (CNEL) 

standard for single-family residential areas. CNEL is a 24-hour weighted average noise level 

with more weight given to noise levels occurring in the evening and nighttime periods. The 

CNEL standard of the county is less stringent than the 45 dBA limit.

As mentioned in the Affected Environment (Section 3.11), the nearest sensitive receptors are 

approximately 7 miles west of the Plan Area. The reference noise level for a single OHV at 

50 feet is 92 dBA. It is unlikely that noise generated at the ISDRA can effect off site 

receptors.

It has been shown that prolonged noise can adversely affect some lizards (e.g., desert iguana, 

Mohave fringe-toes lizard). Laboratory studies show that dune buggy sounds, collected from 

the Imperial Valley, of moderate intensity and short duration cause hearing loss in Colorado 

Desert fringed-toed lizards. However, it is not known whether or not vehicle noise at levels 

and durations anticipated in the desert negatively impact flat-tailed horned lizards. Exposure 

to vehicle sounds reduced hearing detection abilities in desert kangaroo rats for three weeks. 

Hearing reductions lead to the animals’ inability to detect its predator, the sidewinder, for 

those three weeks. Effects are more likely where prolonged, loud noise occurs. 

Alternative 2

Facility development under Alternative 2 would include grading of entry roads and 

construction of interpretive facilities, traffic control areas, ranger stations, parking lots, and 

pit toilets in some of the management areas. Therefore, construction noise exposure under 
329

this alternative would be greater than Alternative 1, which involves minimal or no facility 

development. However, all construction activities would be temporary and would not affect 

any noise-sensitive receptors. No significant construction noise impacts are anticipated.

Under Alternative 2, the North Algodones Dunes Wilderness area would be classified as 

semi-primitive non-motorized, meaning no OHV activities would be allowed in this area. 

The ROS classification for Mammoth Wash and the Adaptive Management Area would be 

semi-primitive motorized, which limits OHV activities. Therefore, OHV activities would 

primarily occur in areas south of SR 78. Additionally, Oldsmobile Hill and Competition Hill 

could potentially be closed from sundown to sun up. OHV activities are not anticipated to 

cause increased noise levels. Furthermore, no noise-sensitive receptors are located within the 

project vicinity. OHV activities associated with Alternative 2 would comply with the 

Imperial County noise standards. Significant OHV noise impacts would not result from the 

implementation of Alternative 2. 

It has been shown that prolonged noise can adversely affect some lizards (e.g., desert iguana, 

Mohave fringe-toes lizard). Laboratory studies show that dune buggy sounds, collected from 

the Imperial Valley, of moderate intensity and short duration cause hearing loss in Colorado 

Desert fringed-toed lizards. However, it is not known whether or not vehicle noise at levels 

and durations anticipated in the desert negatively impact flat-tailed horned lizards. Exposure 

to vehicle sounds reduced hearing detection abilities in desert kangaroo rats for three weeks. 

Hearing reductions lead to the animals’ inability to detect its predator, the sidewinder, for 

those three weeks. Effects are more likely where prolonged, loud noise occurs. 

Alternative 3

Under Alternative 3, facility developments would include grading of some entry roads and 

construction of an interpretive facility, traffic control areas, a parking lot, and pit toilets in 

some of the management areas. Because facility development activity would be less intense, 

construction noise exposure under this alternative would be lower than under Alternative 2. 

All construction activities would be temporary and would not be in the vicinity of any noisesensitive receptors. Therefore, no significant construction noise impacts are anticipated.

Under Alternative 3, the Mammoth Wash, North Algodones Dunes Wilderness, and Adaptive 

Management Areas would be classified as semi-primitive non-motorized, meaning no OHV 

activities would be allowed in these areas. Therefore, OHV activities would be confined to 

less than half of the overall management area. Additionally, Oldsmobile Hill and 

Competition Hill could possibly be closed from sundown to sun up. Overall ambient noise 

levels are not expected to increase as a result of OHV activities. Furthermore, no noisesensitive receptors are located within the project vicinity. OHV activities associated with 

Alternative 3 would comply with the Imperial County noise standards. Significant OHV 

noise impacts would not result from the implementation of Alternative 3.

It has been shown that prolonged noise can adversely affect some lizards (e.g., desert iguana, 

Mohave fringe-toes lizard). Laboratory studies show that dune buggy sounds, collected from 

the Imperial Valley, of moderate intensity and short duration cause hearing loss in Colorado 

Desert fringed-toed lizards. However, it is not known whether or not vehicle noise at levels 

and durations anticipated in the desert negatively impact flat-tailed horned lizards. Exposure 
330

to vehicle sounds reduced hearing detection abilities in desert kangaroo rats for three weeks. 

Hearing reductions lead to the animals’ inability to detect its predator, the sidewinder, for 

those three weeks. Effects are more likely where prolonged, loud noise occurs. 

Alternative 4

Under Alternative 4, short-term construction noise exposure would be similar to Alternative 

2, which would provide the same level of facility development. All construction activities 

would be temporary and would not be in the vicinity of any noise-sensitive receptors. 

Therefore, no significant construction noise impacts are anticipated.

Under Alternative 4, only the North Algodones Dunes Wilderness area would be classified as 

semi-primitive non-motorized. Therefore, implementation of this alternative could result in 

increased OHV activity throughout the ISDRA Planning Area. However, this activity would 

be more dispersed due to the increase in acreage open to OHV use. Further, no sensitive 

noise receptors are located within the project vicinity. OHV activities associated with 

Alternative 4 would comply with all applicable Imperial County noise standards. Adverse 

noise impacts are not anticipated from implementation of this alternative.

It has been shown that prolonged noise can adversely affect some lizards (e.g., desert iguana, 

Mohave fringe-toes lizard). Laboratory studies show that dune buggy sounds, collected from 

the Imperial Valley, of moderate intensity and short duration cause hearing loss in Colorado 

Desert fringed-toed lizards. However, it is not known whether or not vehicle noise at levels 

and durations anticipated in the desert negatively impact flat-tailed horned lizards. Exposure 

to vehicle sounds reduced hearing detection abilities in desert kangaroo rats for three weeks. 

Hearing reductions lead to the animals’ inability to detect its predator, the sidewinder, for 

those three weeks. Effects are more likely where prolonged, loud noise occurs. 

Mitigation Me asures

Significant adverse noise impacts are not anticipated under any of the project alternatives, 

including Alternative 1. No mitigation measures are required. However, BLM will enforce 

the State noise regulations to assist in maintaining acceptable noise level within the ISDRA.

Cumulative Effects

There are several activities within the Planning Area and general vicinity that could add to 

cumulative noise effects, including:

Noise from train movements on the Union Pacific (formerly the Southern Pacific) 

Railroad tracks located along the east side of the Plan Area

Noise associated with occasional recreational and support activities, especially both 

concentrated and dispersed OHV uses of the Plan Area and immediate vicinity 

Vehicular traffic noise on major roadways leading to the Plan Area
331

Intermittent military aircraft maneuvers and military weapons explosions associated 

with the use of the Chocolate Mountain Aerial Gunnery Range (CMAGR) located to 

the northwest of the Plan Area and a gunnery range north of East Mesa 

Occasional military aircraft overflights associated with flight corridors located above 

and adjacent to the Plan Area 

Military helicopter use of the Plan Area as a training ground for the use of night 

vision devices 

Mineral exploration, including drilling by Mesquite Mine and/or Glamis Imperial 

under existing BLM approvals

Construction of utility lines

Construction activities, pursuit activities and medical response activities conducted by 

Border Patrol. These activities may include the use of a helicopter, heavy equipment 

and law enforcement vehicles. 

Natural sources such as wind, rain, thunder, and wildlife
332

4.12 Air Quality

The air quality analysis presented in this section addresses anticipated air quality impacts 

resulting from implementation of the alternatives presented in Chapter 2 of this EIS. 

Assumptions and Assessment Guidelines

The analysis addresses potential local and regional effects from motorized OHV operational 

sources and on-highway vehicular travel that can be expected as a result of project 

implementation. A discussion of the methodology used for estimating on-highway vehicle 

and motorized OHV emissions is provided below.

Vehicle Types

Motorized vehicles are the primary source of emissions associated with the proposed four 

alternative resource management plans. Typically, recreational park and open space land uses 

do not directly emit significant amount of air pollutants. Vehicular trips to and from these 

land uses, however, do emit pollutants. Further, an increase in the number of new daily 

vehicle trips will typically mean an increase in recreational motorized OHV activities at 

ISDRA. 

On-road emissions result from automobile, trucks, and recreational vehicles that travel to and 

from each site, and are proportional to the distance of vehicle travel. Emissions were 

calculated based on assumed average round-trip travel distances and EMFAC7G emission 

factors (CARB, 1997). The emission factors were based on average vehicle speeds, ambient 

temperature, vehicle weight classification, and engine type. The manufacture of motor 

vehicles (including OHV models) that do not meet federal and California CAA requirements 

to reduce tailpipe emissions could be discontinued. The emission estimates do not account 

for potential emission reductions that would occur if vehicles are converted to clean fuels or 

if electric vehicles are substituted for gasoline- or diesel-fueled vehicles.

Off-highway emissions result from the operation of mobilized OHVs at the site. Off-road 

emissions are proportional to the length of activity. All OHV activities can be expected to 

vary hour-by-hour in their activity. Operational profiles are not available for these OHV 

activities over the course of an entire day, hour-by-hour. The estimated profiles are based on 

the concept of peak OHV activity. The peak hour(s) is defined as the hour(s) of the day at 

which maximum activity occurs. There can be one or more such peaks in a 24-hour period. 

For the purpose of this air quality analysis, the peak OHV activity levels would occur when 

an estimated 3.5 person per occupant’s on-road vehicle are operating their OHV at the same 

hour. (Note: the average occupancy rate of on-road vehicle is 3.5 persons per vehicle for this 

analysis. It is acknowledged that this is a peak estimate and it is likely higher than would 

actually occur.) Emissions were calculated by multiplying off-road emission factors by the 

estimated number of OHVs in operation, and the average operating hour of each piece of 

OHV. It was assumed that each OHV would operate 6 hours per day. Off-highway emission 

factors recently published by the CARB were used to calculate emissions. 
333

Motorized Vehicle Generated Dust

The principal pollutant of concern emitted by motorized OHV is PM10 because of the 

relatively large quantity of PM10 dust emissions disturbed by OHVs operating over unpaved 

surface, and the relatively low ambient air quality standard for PM10. Soil disturbance 

activities, such as motorized vehicle travel on the sand dunes, can represent substantial 

sources of fugitive dust depending on the level of activity, the specific vehicle activities 

being conducted, and prevailing meteorological conditions. It should be noted that most of 

the PM10 emissions are from wind erosions, which are a major source of PM10 emissions 

throughout the ISDRA. In addition, the newly adopted PM2.5 standard is not yet applicable.

PM10 dust emissions can adversely affect sensitive receptors (i.e., people who are more 

susceptible to the adverse impact of air pollutants). These include the elderly, young 

children, and those individuals suffering from respiratory disorders. Although most dust 

emissions are readily filtered by human breathing passages, tiny particles can easily bypass 

this natural filtering system and lodge deep in the lungs. Many scientific studies have linked 

breathing PM to a series of significant health problems, including: aggravated asthma, 

increased respiratory symptoms like coughing and difficult or painful breathing, chronic 

bronchitis, decreased lung function, premature death. Large-diameter dust, which settles out 

on nearby foliage and other surfaces, is more a soiling nuisance than a potential health 

impact. Areas near the OHV sites would be the most susceptible to this nuisance from OHV 

activities.

Fugitive dust emissions would also be generated from on-highway vehicle travel over paved 

road that lead to the ISDRA. These fugitive dust emissions were calculated using the 

methodology in the CEQA Air Quality Handbook (SCAQMD, 1993) and AP-42 Volume I: 

Stationary Point and Area Sources (EPA, 1995). Fugitive dust emission calculations are 

presented in Appendix C, and a summary of emissions is presented in the discussion of 

alternatives in this analysis.

Evaluation Criteria

To determine the severity of impacts, a set of criteria is established for peak daily and annual 

average concentrations for each pollutant. Emissions below these levels are assumed to 

present no threat to ambient air quality. An alternative that would generate emissions in 

excess of these limits would result in adverse impacts to air quality in the region.

Although the Imperial County Air Pollution Control District (ICAPCD) has not developed 

specific guidelines for evaluating air quality impacts for proposed actions undergoing 

environmental review, the ICAPCD has established peak daily air pollutant emission limits 

that, when exceeded, indicate that a source could have an impact on ambient air quality. 

These emission threshold levels are shown in Table 4.12-1.

EPA sets de minimis conformity thresholds, and they refer to the maximum allowable 

increase in direct and indirect emissions between each projected year and the baseline year 

for each criteria pollutant in non-attainment and maintenance areas (40 CFR, Section 51.853 

[b]). Emissions below these levels are presumed to conform to the SIP within the meaning of 

the General Conformity Rule. If the total direct and indirect emissions from a federal action 

would not exceed the thresholds for criteria pollutants in any year, the federal action is 
334

deemed de minimis and exempted from conformity requirements. If the total emissions are 

equal or greater than the de minimis levels for the pollutant in any year, a formal conformity 

determination is required for that pollutant. EPA de minimis levels are provided in 

Table 4.12-1.

Table 4.12-1 Pollutant Emission Criteria

Criteria Pollutant

ICAPCD Criteria

(pounds per day)

Clean Air Act

De Minimis Levels

(tons/year)

CO 550 100

NOx 137 100

ROG 137 50

SOx 137 100

PM10 137 100

Source: ICAPCD, 1993; EPA, 1993.

Note: California defines ROG as VOC (volatile organic compounds)

Future Baseline

Impacts of the alternatives are assessed by comparison with a future baseline scenario that 

serves as a benchmark for comparison. This method is used to account for impacts attributed 

to regional growth, independent of the individual resource management plan alternatives. 

Development assumptions outside the ISDRA are the same for both the future baseline and 

all project alternatives. The assumptions are based on current growth forecasts for Imperial 

County and the SSAB region.

The future baseline is defined as the scenario year 2012-2013 with no changes to interim 

management, which is the same as the No Action Alternative under Alternative 4. Under the 

Future baseline, existing attendance for the 1999-2000 season at ISDRA is assumed to 

increase by 5 percent annually.

Relative to air quality, a notable major emission concern is the PM10 fugitive dust emissions, 

both natural and mechanical. Wind-blown dust emission generates approximately 

173.35 tons per day (or 346,000 pounds per day) in Imperial County during the year 2000. 

(This does not include windblown dust from disturbed vacant land such as the ISDRA, so the 

actual amount of wind blown dust is greater.) Entrained dust emission from vehicles on 

paved and unpaved surfaces generates approximately 3.67 and 38.92 tons per day, 

respectively, in Imperial County during the year 2000. Any additional construction and offroad recreational activities occurring in the present and near future would increase the PM10

emission beyond these already significant levels.

Regional air pollutant emissions projected under the future baseline (2012-2013) associated 

with motor vehicle and OHV operations are shown in Table 4.12-2. A comparison of the 

future baseline with the existing condition (1999-2000) is also provided.
335

Table 4.12-2 Estimated Annual Air 

Emissions Associated with the Future Baseline

Emissions (tons/year)

Emission Source CO NOx ROG/HC SOx PM10

Future Baseline

 On-road Motor Vehicles 149.66 47.42 52.41 1.49 52.94

 Off-highway Vehicles 1,086.73 428.57 64.29 9.18 2,568.24

Future Baseline Total (2012-2013) 1,236.39 476.00 116.70 10.67 2,621.19

Baseline Condition (1999-2000) 599.25 230.21 56.38 5.14 1,263.64

Note: Estimated PM10 emission includes both exhaust and fugitive dust emissions.

Source: CH2M HILL, 2002

Emission estimates for peak daily vehicles were prepared using the EMFAC7G vehicle 

emission rate model. The estimated number of motor vehicles corresponds to projected 

traffic volumes for major holiday weekends (refer to Section 4.9). The number of OHVs is 

proportionate to the total visits provided in Table 4.1-1. Table 4.12-3 summarizes the peak 

daily vehicle and OHV emissions analyses for year 2012-2013. 

Impacts

The following discussion addresses potential air quality impacts from both a peak daily and 

annual average perspective for each alternative. Peak daily impacts are related to emissions 

produced during the six major holiday weekends, and typically involve an increase in dust 

(suspended particulates) as well as OHV and motor vehicle exhaust. Annual emission 

impacts are related to emissions produced by OHV activities and vehicle trips over a 

12-month period.

Alternative 1

Annual air pollutant emission estimates for Alternative 1 are provided in Table 4.12-4, along 

with a comparison to the future baseline. Because annual attendance at the ISDRA is 

anticipated to increase under this alternative, the annual emission results show that estimated 

emission levels in 2012-2013 would increase over the emission levels for the future baseline. 

Therefore, the total net emissions associated with this alternative would exceed the de 

minimis threshold levels. The impacts on air quality would be significant under Alternative 1 

scenario.
336

Table 4.12-3 Estimated Peak Daily Air Emissions Associated with the Future Baseline

Emissions (pounds/day)

Emission Source CO NOx ROG/HC SOx PM10

Halloween

On-road Motor Vehicles 5,658.71 1,793.16 1,981.84 56.27 2,001.80

Off-highway Vehicles 11,413.89 4,501.25 675.19 96.46 11,150.37

Total 17,072.60 6,294.41 2,657.02 152.72 13,152.17

Thanksgiving

On-road Motor Vehicles 9,699.12 3,073.50 3,396.90 96.44 3,431.11

Off-highway Vehicles 19,563.57 7,715.21 1,157.28 165.33 19,111.90

Total 29,262.69 10,788.71 4,554.18 261.77 22,543.00

New Year

On-road Motor Vehicles 6,465.91 2,048.95 2,264.54 64.29 2,287.34

Off-highway Vehicles 13,042.03 5,143.33 771.50 110.21 12,740.92

Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Martin Luther King’s Birthday

On-road Motor Vehicles 4,040.41 1,280.34 1,415.06 40.17 1,429.31

Off-highway Vehicles 8,149.68 3,213.96 482.09 68.87 7,961.53

Total 12,190.09 4,494.30 1,897.15 109.05 9,390.84

President’s Day

On-road Motor Vehicles 8,080.81 2,560.69 2,830.12 80.35 2,858.62

Off-highway Vehicles 16,299.36 6,427.92 964.19 137.74 15,923.05

Total 24,380.17 8,988.60 3,794.31 218.09 18,781.68

Easter

On-road Motor Vehicles 6,465.91 2,048.95 2,264.54 64.29 2,287.34

Off-highway Vehicles 13,042.03 5,143.33 771.50 110.21 12,740.92

Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Note: Estimated PM10 emission includes both exhaust and fugitive dust emissions.

Source: CH2M HILL, 2002
337

Table 4.12-4 Estimated Annual Air Emissions Associated with Alternative 1

Emissions (tons/year)

Emission Source CO NOx ROG/HC SOx PM10

Alternative 1 

 On-road Motor Vehicles 172.19 54.57 60.31 1.71 60.91

 Off-Highway Vehicles 1,250.35 273.52 41.03 10.57 2,954.91

Alternative 1 Total (2012-

2013)

1,422.54 322.51 95.18 7.40 120.67

Future Baseline Total (2012-

2013)

1,236.39 476.00 116.70 10.67 2,621.19

Total Net Emission 186.15 71.66 17.57 1.61 394.64

De Minimis Thresholds 100.00 100.00 50.00 100.00 100.00

Note: Estimated PM10 emission includes both exhaust and fugitive dust emissions.

Source: CH2M HILL, 2002

Emission estimates for peak daily vehicles were prepared using the EMFAC7G vehicle 

emission rate model. The estimated number of motor vehicles corresponds to projected 

traffic volumes for major holiday weekends (refer to Section 4.9). The number of OHVs is 

proportionate to the total visits provided in Table 4.1-1. Emission estimates for Alternative 1 

and a comparison to the Future baseline are presented in Table 4.12-5.

As shown in Table 4.12-5, the peak daily emissions for CO, NOx and PM10 under this 

alternative would exceed the ICAPCD daily emission threshold limits.

Because Alternative 1 would result in an increase in peak daily emissions for CO, NOx and 

PM10, significant air quality impacts would result from implementation of this alternative.

Alternative 2

Annual air pollutant emission estimates compared with the future baseline for Alternative 2 

are provided in Table 4.12-6. The annual emission results show that emissions in 2012-2013 

would be lower under Alternative 2 than under the future baseline because of an anticipated 

decrease in visitor use under this alternative. The net change in annual emissions that would 

result from implementation of this alternative would be below the federal de minimis

thresholds.

Emission estimates for peak daily vehicles were prepared using the EMFAC7G vehicle 

emission rate model. The estimated number of motor vehicles corresponds to projected 

traffic volumes for major holiday weekends (refer to Section 4.9). The number of OHVs is 

proportionate to the total visits provided in Table 4.1-1. Emission estimates for the 

Alternative 2 and a comparison to the Future Baseline are presented in the Table 4.12-7.

As shown in Table 4.11-7, the net peak daily emissions for Alternative 2 would be below the 

criteria established by ICAPCD. Therefore, no adverse air quality impact is expected to 

result under this alternative during major holiday weekends.
338

Table 4.12-5 Estimated Peak Daily Air Emissions Associated with Alternative 1

Emissions (pounds/day)

Emission Source CO NOx ROG/HC SOx PM10

Halloween

 On-road Motor Vehicles 6,508.33 2,062.39 2,279.40 64.71 2,302.35

 Off-highway Vehicles 13,127.60 5,177.08 776.56 110.94 12,824.52

Total 19,635.94 7,239.47 3,055.96 175.65 15,126.88

Future Baseline Total 17,072.60 6,294.41 2,657.02 152.72 13,152.17

Net Emissions 2,563.34 945.06 398.94 22.93 1,974.71

Thanksgiving

 On-road Motor Vehicles 11,158.45 3,535.94 3,907.99 110.95 3,947.35

 Off-highway Vehicles 22,507.11 8,876.04 1,331.41 190.20 21,987.48

Total 33,665.56 12,411.99 5,239.40 301.15 25,934.83

Future Baseline Total 29,262.69 10,788.71 4,554.18 261.77 22,543.00

Net Emissions 4,402.87 1,623.28 685.22 39.38 3,391.83

New Year

 On-road Motor Vehicles 7,437.31 2,356.77 2,604.75 73.95 2,630.98

 Off-highway Vehicles 15,001.39 5,916.04 887.41 126.77 14,655.05

Total 22,438.70 8,272.81 3,492.15 200.72 17,286.03

Future Baseline Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Net Emissions 2,930.77 1,080.53 456.11 26.21 2,257.77

Martin Luther King’s Birthday

 On-road Motor Vehicles 4,650.12 1,473.55 1,628.60 46.24 1,645.00

 Off-highway Vehicles 9,379.50 3,698.96 554.84 79.26 9,162.95

Total 14,029.62 5,172.51 2,183.44 125.50 10,807.95

Future Baseline Total 12,190.09 4,494.30 1,897.15 109.05 9,390.84

Net Emissions 1,839.53 678.21 286.29 16.45 1,417.11

President’s Day

 On-road Motor Vehicles 9,300.50 2,947.19 3,257.29 92.48 3,290.09

 Off-highway Vehicles 18,759.53 7,398.13 1,109.72 158.53 18,326.42

Total 28,060.03 10,345.31 4,367.01 251.01 21,616.52

Future Baseline Total 24,380.17 8,988.60 3,794.31 218.09 18,781.68

Net Emissions 3,679.86 1,356.71 572.70 32.92 2,834.84

Easter

 On-road Motor Vehicles 7,437.31 2,356.77 2,604.75 73.95 2,630.98

 Off-highway Vehicles 15,001.39 5,916.04 887.41 126.77 14,655.05

Total 22,438.70 8,272.81 3,492.15 200.72 17,286.03

Future Baseline Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Net Emissions 2,930.77 1,080.53 456.11 26.21 2,257.77

ICAPCD Criteria 550.00 137.00 137.00 137.00 137.00

Note: Estimated PM10 emission includes both exhaust and fugitive dust emissions. Source: CH2M HILL, 2001
339

Table 4.12-6 Estimated Annual Air Emissions Associated with Alternative 2

Emissions (tons/year)

Emission Source CO NOx ROG/HC SOx PM10

Alternative 2 

On-road Motor 

Vehicles

136.11 43.13 47.67 1.35 48.15

Off-highway 

Vehicles

988.33 389.76 58.46 8.35 2,335.68

Alternative 2 Total (2012-

2013)

1,124.43 432.89 106.13 9.71 2,383.83

Future Baseline Total 

(2012-2013)

1,236.39 476.00 116.70 10.67 2,621.19

Total Net Emission - 111.96 - 43.11 - 10.57 - 0.96 - 237.36

De Minimis Thresholds 100.00 100.00 50.00 100.00 100.00

Note: Estimated PM10 emission includes both exhaust and fugitive dust emissions.

Source: CH2M HILL, 2001

Alternative 3

Annual air pollutant emission estimates compared with the future baseline are provided in 

Table 4.12-8. The annual emission results show that emissions in 2012-2013 would be lower 

under Alternative 3 than under the future baseline because of an anticipated decrease in 

visitor use under this alternative. This decrease in annual emissions resulting from 

implementation of this alternative would be less than under the Alternative 2, and would be 

below federal de minimis thresholds.

Emission estimates for peak daily vehicles were prepared using the EMFAC7G vehicle 

emission rate model. The estimated number of motor vehicles corresponds to projected 

traffic volumes for major holiday weekends (refer to Section 4.9). The number of OHVs is 

proportionate to the total visits provided in Table 4.1-1. Emission estimates for Alternative 3 

and a comparison to the Future baseline are presented in the Table 4.12-9.

As shown in Table 4.11-9, the net peak daily emissions for the Alternative 3 would not 

exceed the criteria established by ICAPCD. Therefore, no adverse air quality impact is 

expected under this alternative during major holiday weekends. These impacts would be less 

than those anticipated under Alternative 2.
340

Table 4.12-7 Estimated Peak Daily Air Emissions Associated with the Alternative 2

Emissions (pounds/day)

Emission Source CO NOx ROG/HC SOx PM10

Halloween

 On-road Motor Vehicles 4,616.60 1,462.93 1,616.86 45.90 1,633.14

 Off-highway Vehicles 9,311.88 3,672.29 550.84 78.69 9,096.90

Total 13,928.48 5,135.22 2,167.70 124.60 10,730.04

Future Baseline Total 17,072.60 6,294.41 2,657.02 152.72 13,152.17

Net Emissions -3,144.12 -1,159.19 -489.32 -28.12 -2,422.13

Thanksgiving

 On-road Motor Vehicles 7,912.40 2,507.32 2,771.14 78.67 2,799.05

 Off-highway Vehicles 15,959.68 6,293.96 944.09 134.87 15,591.21

Total 23,872.08 8,801.28 3,715.23 213.55 18,390.26

Future Baseline Total 29,262.69 10,788.71 4,554.18 261.77 22,543.00

Net Emissions -5,390.61 -1,987.43 -838.95 -48.22 -4,152.74

New Year

 On-road Motor Vehicles 5,274.24 1,671.33 1,847.18 52.44 1,865.79

 Off-highway Vehicles 10,638.38 4,195.42 629.31 89.90 10,392.77

Total 15,912.62 5,866.74 2,476.49 142.34 12,258.55

Future Baseline Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Net Emissions -3,595.31 -1,325.54 -559.55 -32.17 -2,769.71

Martin Luther King’s Birthday

 On-road Motor Vehicles 3,296.07 1,044.47 1,154.37 32.77 1,166.00

 Off-highway Vehicles 6,648.33 2,621.88 393.28 56.18 6,494.83

Total 9,944.40 3,666.35 1,547.66 88.96 7,660.83

Future Baseline Total 12,190.09 4,494.30 1,897.15 109.05 9,390.84

Net Emissions -2,245.69 -827.95 -349.49 -20.09 -1,730.01

President’s Day

 On-road Motor Vehicles 6,594.50 2,089.70 2,309.57 65.57 2,332.83

 Off-highway Vehicles 13,301.41 5,245.63 786.84 112.41 12,994.31

Total 19,895.91 7,335.32 3,096.42 177.98 15,327.15

Future Baseline Total 24,380.17 8,988.60 3,794.31 218.09 18,781.68

Net Emissions -4,484.26 -1,653.28 -697.89 -40.11 -3,454.53

Easter

 On-road Motor Vehicles 5,274.24 1,671.33 1,847.18 52.44 1,865.79

 Off-highway Vehicles 10,638.38 4,195.42 629.31 89.90 10,392.77

Total 15,912.62 5,866.74 2,476.49 142.34 12,258.55

Future Baseline Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Net Emissions -3,595.31 -1,325.54 -559.55 -32.17 -2,769.71

ICAPCD Criteria 550.00 137.00 137.00 137.00 137.00

Note: Estimated PM10 emission includes both exhaust and fugitive dust emissions. Source: CH2M HILL, 2002
341

Table 4.12-8 Estimated Annual Air Emissions Associated with Alternative 3

Emissions (tons/year)

Emission Source CO NOx ROG/HC SOx PM10

Alternative 3

On-road Motor Vehicles 123.72 39.20 43.33 1.23 43.77

Off-highway Vehicles 898.37 354.29 53.14 7.59 2,123.09

Alternative 3 Total (2012-2013) 1,022.09 393.49 96.47 8.82 2,166.86

Future Baseline Total (2012-

2013)

1,236.39 476.00 116.70 10.67 2,621.19

Total Net Emission -214.30 -82.51 -20.23 -1.85 -454.33

De Minimis Thresholds 100.00 100.00 50.00 100.00 100.00

Note: Estimated PM10 emission includes both exhaust and fugitive dust emissions.

Source: CH2M HILL, 2002

Alternative 4

Annual air pollutant emission estimates for the Alternative 4 are provided in Table 4.12-10, 

along with a comparison to the future baseline. Because annual attendance at the ISDRA is 

not anticipated to change under this alternative, the annual emission results show that 

emissions in 2012-2013 would be the same as under the Future baseline. Therefore, the total 

net emission associated with this alternative would be zero, and would not exceed the federal 

de minimis thresholds.

Emission estimates for peak daily vehicles were prepared using the EMFAC7G vehicle 

emission rate model. The estimated number of motor vehicles corresponds to projected 

traffic volumes for major holiday weekends (refer to Section 4.9). The number of OHVs is 

proportionate to the total visits provided in Table 4.1-1. Emission estimates for Alternative 4 

and a comparison to the Future baseline are presented in the Table 4.12-11.

As shown in Table 4.12-11, the net peak daily emissions for Alternative 4 would result in the 

same regional emissions impacts as the Future baseline. Therefore, the estimated net 

emissions would be zero, and would not exceed the ICAPCD daily emission threshold limits. 

The air quality impacts would be somewhat less than those anticipated under Alternative 1, 

and greater than those under the Alternatives 2 and 3.
342

Table 4.12-9 Estimated Peak Daily Air Emissions Associated with Alternative 3

Emissions (pounds/day)

Emission Source CO NOx ROG/HC SOx PM10

Halloween

 On-road Motor Vehicles 4,677.10 1,482.10 1,638.05 46.51 1,654.54

 Off-highway Vehicles 9,433.91 3,720.42 558.06 79.72 9,216.11

Total 14,111.01 5,202.52 2,196.11 126.23 10,870.65

Future Baseline Total 17,072.60 6,294.41 2,657.02 152.72 13,152.17

Net Emissions -2,961.59 -1,091.89 -460.91 -26.49 -2,281.52

Thanksgiving

 On-road Motor Vehicles 8,016.12 2,540.19 2,807.46 79.71 2,835.74

 Off-highway Vehicles 16,168.88 6,376.46 956.47 136.64 15,795.58

Total 24,185.00 8,916.64 3,763.93 216.34 18,631.32

Future Baseline Total 29,262.69 10,788.71 4,554.18 261.77 22,543.00

Net Emissions -5,077.69 -1,872.07 -790.25 -45.43 -3,911.68

New Year

 On-road Motor Vehicles 5,346.26 1,694.15 1,872.41 53.16 1,891.26

 Off-highway Vehicles 10,783.65 4,252.71 637.91 91.13 10,534.69

Total 16,129.92 5,946.86 2,510.31 144.29 12,425.95

Future Baseline Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Net Emissions -3,378.01 -1,245.42 -525.73 -30.22 -2,602.31

Martin Luther King’s 

Birthday

 On-road Motor Vehicles 3,339.02 1,058.09 1,169.42 33.20 1,181.19

 Off-highway Vehicles 6,734.96 2,656.04 398.41 56.92 6,579.47

Total 10,073.99 3,714.13 1,567.82 90.12 7,760.67

Future Baseline Total 12,190.09 4,494.30 1,897.15 109.05 9,390.84

Net Emissions -2,116.10 -780.17 -329.33 -18.93 -1,630.17

President’s Day

 On-road Motor Vehicles 6,681.19 2,117.17 2,339.94 66.43 2,363.50

 Off-highway Vehicles 13,476.26 5,314.58 797.19 113.88 13,165.13

Total 20,157.46 7,431.75 3,137.12 180.32 15,528.64

Future Baseline Total 24,380.17 8,988.60 3,794.31 218.09 18,781.68

Net Emissions -4,222.71 -1,556.85 -657.19 -37.77 -3,253.04

Easter

 On-road Motor Vehicles 5,346.26 1,694.15 1,872.41 53.16 1,891.26

 Off-highway Vehicles 10,783.65 4,252.71 637.91 91.13 10,534.69

Total 16,129.92 5,946.86 2,510.31 144.29 12,425.95

Future Baseline Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Net Emissions -3,378.01 -1,245.42 -525.73 -30.22 -2,602.31

ICAPCD Criteria 550.00 137.00 137.00 137.00 137.00

Note: Estimated PM10 emission includes both exhaust and fugitive dust emissions. Source: CH2M HILL, 2002
343

Table 4.12-10 Estimated Annual Air Emissions Associated with Alternative 4

Emissions (tons/year)

Emission Source CO NOx ROG/HC SOx PM10

Alternative 4

On-road Motor Vehicles 149.66 47.42 52.41 1.49 52.94

Off-highway Vehicles 1,086.73 428.57 64.29 9.18 2,568.24

Alternative 4 Total (2012-

2013)

1,236.39 476.00 116.70 10.67 2,621.19

Future Baseline Total (2012-

2013)

1,236.39 476.00 116.70 10.67 2,621.19

Total Net Emission 0.00 0.00 0.00 0.00 0.00

De Minimis Thresholds 100.00 100.00 50.00 100.00 100.00

Note: Estimated PM10 emission includes both exhaust and fugitive dust emissions.

Source: CH2M HILL, 2002

Conformity Statement

The 1990 amendments to the federal CAA require federal agencies to ensure that their 

actions conform to the applicable SIP. The SIP is a plan that provides for implementation, 

maintenance, and enforcement of the NAAQS, and it includes emission limitations and 

control measures. Conformity to a SIP, as defined in the CAA, means conforming to the 

purposes of the SIP to reduce the severity and number of violations to the NAAQS and 

achieve timely attainment of such standards.

Pursuant to Section 176(c) of the Clean Air Act, as amended by the 1990 amendments, and 

the General Conformity Rule at 40 CFR Parts 51 and 93, the air quality analysis establishes 

that the emissions associated with the proposed project are below the de minimis levels and 

are not regionally significant because they do not exceed 10 percent of the total emission 

inventory for any criteria pollutants in the SSAB. If the difference between emissions of 

criteria pollutants associated with Alternative 2 and those of Alternative 1 would be below 

specified the de minimis levels and Alternative 2 emissions would not be regionally 

significant (i.e., greater than 10 percent of the emissions budget of the Air Basin), then no 

further evaluation is needed for the pollutant in any year. If the net emissions would be equal 

to or greater than the de minimis levels for the pollutant in any year, a formal Conformity 

Determination is required for that pollutant. For example, if Alternative 1 becomes the 

preferred action, then the net emissions under Alternative 1 would exceed de minimis levels 

for CO, NOX and PM10. Implementation of Alternative 1 may adversely impact the 

attainment of the SIP.

Implementation of the Alternatives 2, 3, and 4 would not adversely affect the attainment of 

the SIP. Consequently, Alternative 2 for these alternatives is exempt from the conformity 

determination requirement of the General Conformity Rule.
344

Table 4.12-11 Estimated Peak Daily Air Emissions Associated with Alternative 4

Emissions (pounds/day)

Emission Source CO NOx ROG/HC SOx PM10

Halloween

 On-road Motor Vehicles 5,658.71 1,793.16 1,981.84 56.27 2,001.80

 Off-highway Vehicles 11,413.89 4,501.25 675.19 96.46 11,150.37

Total 17,072.60 6,294.41 2,657.02 152.72 13,152.17

Future Baseline Total 17,072.60 6,294.41 2,657.02 152.72 13,152.17

Net Emissions 0.00 0.00 0.00 0.00 0.00

Thanksgiving

 On-road Motor Vehicles 9,699.12 3,073.50 3,396.90 96.44 3,431.11

 Off-highway Vehicles 19,563.57 7,715.21 1,157.28 165.33 19,111.90

Total 29,262.69 10,788.71 4,554.18 261.77 22,543.00

Future Baseline Total 29,262.69 10,788.71 4,554.18 261.77 22,543.00

Net Emissions 0.00 0.00 0.00 0.00 0.00

New Year

 On-road Motor Vehicles 6,465.91 2,048.95 2,264.54 64.29 2,287.34

 Off-highway Vehicles 13,042.03 5,143.33 771.50 110.21 12,740.92

Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Future Baseline Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Net Emissions 0.00 0.00 0.00 0.00 0.00

Martin Luther King’s Birthday

 On-road Motor Vehicles 4,040.41 1,280.34 1,415.06 40.17 1,429.31

 Off-highway Vehicles 8,149.68 3,213.96 482.09 68.87 7,961.53

Total 12,190.09 4,494.30 1,897.15 109.05 9,390.84

Future Baseline Total 12,190.09 4,494.30 1,897.15 109.05 9,390.84

Net Emissions 0.00 0.00 0.00 0.00 0.00

President’s Day

 On-road Motor Vehicles 8,080.81 2,560.69 2,830.12 80.35 2,858.62

 Off-highway Vehicles 16,299.36 6,427.92 964.19 137.74 15,923.05

Total 24,380.17 8,988.60 3,794.31 218.09 18,781.68

Future Baseline Total 24,380.17 8,988.60 3,794.31 218.09 18,781.68

Net Emissions 0.00 0.00 0.00 0.00 0.00

Easter

 On-road Motor Vehicles 6,465.91 2,048.95 2,264.54 64.29 2,287.34

 Off-highway Vehicles 13,042.03 5,143.33 771.50 110.21 12,740.92

Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Future Baseline Total 19,507.93 7,192.28 3,036.04 174.51 15,028.26

Net Emissions 0.00 0.00 0.00 0.00 0.00

ICAPCD Significance 

Thresholds

550.00 137.00 137.00 137.00 137.00

Note: Estimated PM10 emission includes both exhaust and fugitive dust emissions. Source: CH2M HILL, 2002
345

Mitigation Measures

Currently Rule 800 Fugitive Dust Control Requirements for Control of Fine Particulate 

Matter (PM-10) as approved by the Imperial County Air Pollution Control District includes 

exempt activities under section E. Exemption E.9 states “The recreational use of public 

lands, including but not limited to Off-Road Vehicles, all-terrain vehicles, trucks, cars, 

motorcycles, motorbikes or motor buggies.” This exempts BLM’s ISDRA from Rule 800. 

However, ICAPCD has informed BLM of its intent to update their PM10 SIP. It is 

anticipated that the updated SIP will require BLM to develop and implement a dust control 

plan for the land that it manages in Imperial County. The following measures could be 

implemented to reduce potential air quality impacts as BLM’s Dust Control Plan:

Apply nontoxic chemical soil stabilizers, according to manufacturers' specifications, to all 

active staging areas (unpaved graded areas for OHV and visitors’ parking, wash road and 

road to Dune Buggy Flats). 

Wet roads prior to heavy use weekends.

Pave parking lots and access roads at least 100 feet onto the site from main road or highway, 

as use and funding allows.

Reduce traffic speeds on all unpaved roads near other users to 15 mph or less to reduce 

health affects to other users.

Sweep all paved streets once a day if visible sand materials are carried to adjacent streets 

(recommend water sweepers with reclaimed water).

Configure new access roads and parking lots to minimize traffic interference and idle exhaust 

emission.

Restrict motorized access to vendor areas by flagging, signing and law enforcement as 

required.

Provide temporary traffic control during peak OHV activities to improve traffic flow (e.g., 

flag person).

Initially some or all of these activities could be conducted to reduce the amount of dust in the 

ISDRA without monitoring activities. The ICACPD is in the process of revising the SIP. 

Once EPA approves this plan, then BLM, in conjunction with EPA and ICACPD through 

implementation of the SIP, will determine the need for monitoring. It is anticipated that air 

monitors may be located in the Wilderness Area and the Adaptive Management Areas. At 

the request of a regulatory agency, monitors will be installed at the weather stations 

previously identified in this EIS to provide additional information to direct these mitigation 

measures.
346

Cumulative Effects

Gateway of the Americas: The Gateway of the Americas Specific Plan Area (Gateway) is a 

1,775-acre master-planned industrial and commercial complex owned by private parties and 

federal, state, and local agencies. Retail shopping, business offices, and lodging would be 

developed in response to the traffic from the Port of Entry. Secondary impacts from the 

Gateway project include short-term air quality impacts in the SSAB as a result of 

construction activities associated with the development of industrial, commercial, and 

transportation-related services.

Imperial County prepared the Final EIR for the Gateway Specific Plan in 1997 (Imperial 

County Planning Department, 1997). The project is in various stages of development in the 

initial construction phase (Phase 1). Phase 2 is expected to continue for 20 to 40 years (IID 

and BOR, 2002).

North Baja Pipeline, LLC: North Baja Pipeline, LLC proposes to build and operate a new 

natural-gas pipeline system that would transport 500 million cubic feet per day of natural gas 

from a proposed interconnection with an existing El Paso Natural Gas Company pipeline in 

Ehrenberg, Arizona to the U.S. and Mexico border. The North Baja Pipeline Project includes 

construction of roughly 80 miles of pipe, a compressor station, two new meter stations, and 

other ancillary facilities. 

Secondary impacts from the North Baja Pipeline project include short-term air quality 

impacts in the SSAB as a result of construction activities and later due to maintenance 

activities. The Federal Energy Regulatory Commission (FERC), the CSLC, and the BLM 

jointly prepared a DEIS/EIR for the proposed project in July 2001. A Final EIS/EIR was 

released in the summer of 2002. A record of decision has been signed. The construction 

phase of this project is completed as the ISDRA EIS is being finalized.

Coachella Valley Water Management Plan: The Coachella Valley Water District (CVWD) 

prepared the Coachella Valley Water Management Plan to provide an overall program for 

managing its surface and groundwater resources in the future (CVWD, 2000). 

Implementation of the Water Management Plan would involve construction of various 

facilities for treatment of water and development of additional policies to implement 

increased conservation. The potential environmental impacts of the Water Management Plan 

have not been fully assessed at this time, but short-term air quality impacts in the SSAB as a 

result of construction activities are anticipated.

The draft CVWD Water Management EIR is being prepared by CVWD. A Notice of 

Preparation (NOP) was originally filed with the State Clearinghouse in November 1995. A 

revised NOP was issued in March 2000. It is anticipated that the EIR, once completed, will 

include mitigation measures to reduce and/or avoid air quality impacts.

Imperial Irrigation District Water Conservation Plan: The Imperial Irrigation District (IID) 

Water Conservation and Transfer Project and Habitat Conservation Plan (Water 
347

Conservation and Transfer Project and HCP) consists of the conservation by IID of up to 

300,000 acre-feet of Colorado River water per year, and the subsequent transfer of all or a 

portion of the conserved water to San Diego County Water Authority (SDCWA), CVWD, 

and/or the Metropolitan Water District of Southern California (Metropolitan). The water 

conservation program includes the voluntary participation of Imperial Valley landowners and 

tenants to implement on-farm conservation methods that could include alternative water 

management techniques, water delivery system alternatives, conveyance facility lining, or 

other measures.

IID and BOR are the lead agencies for the preparation of a Draft EIR/EIS for the IID Water 

Conservation and Transfer Project and HCP, which was released to the public in January 

2002. A final EIR/EIS is expected to be completed in 2002. 

As a result of the water conservation program, implementation of the Water Conservation 

and Transfer Project is anticipated to result in short-term and long-term impacts to air quality 

in the SSAB. The Draft EIR/EIS includes mitigation measures to reduce and/or avoid air 

quality impacts from construction activities in the Imperial Valley. However, other indirect 

air quality impacts in the SSAB are considered significant and unavoidable. Biological 

resources impacts to desert species, such as the flat-tailed horned lizard, Peirson's milk-vetch, 

and desert tortoise also would occur. However, the proposed HCP covers incidental take of 

these species through avoidance strategies and mitigation measures. In addition, depending 

on the alternative selected, the project could result in adverse socioeconomic impacts in 

Imperial County. Mitigation measures to avoid such impacts are anticipated to be 

implemented if an alternative that would result in adverse socioeconomic impacts were 

selected as the preferred alternative. 

Salton Sea Restoration Plan: The Salton Sea Restoration Project includes actions to stabilize 

the elevation and reduce the salinity of the Salton Sea, pursuant to the Salton Sea 

Reclamation Act of 1998 [Public Law (PL) 105-372]. To implement this directive, the Salton 

Sea Authority, as the California lead agency under CEQA, and BOR, as the federal lead 

agency under NEPA, released a Draft EIS/EIR in January 2000 that evaluated proposed 

Salton Sea Restoration Project alternatives. A revised Draft EIS/EIR, including different 

alternatives and revised modeling and impact analysis, is currently being prepared. 

Although environmental documentation has not been completed on the Salton Sea 

Restoration Project, it is anticipated that short-term air quality impacts in the SSAB would 

occur as a result of construction activities associated with project implementation. It is also 

anticipated that the Draft EIS/EIR, once completed, will include mitigation measures to 

reduce and/or avoid air quality impacts.

Coachella Canal Lining: This project involves the lining of the remaining 33.4 miles of the 

Coachella Canal, which currently loses approximately 32,350 acre-feet per year through 

seepage. This canal lining project will adversely affect biological resources by loss of 

riparian and wetland habitat in Salt Creek and adjacent to the canal, which are supported by 

canal leakage. Affected desert species include the desert tortoise. The canal lining project 
348

will also have short-term air quality impacts in the SSAB associated with construction within 

the right-of-way of the Coachella Canal. 

A revised and updated Draft EIS/EIR for the Coachella Canal Lining Project was circulated 

for public review by Reclamation and CVWD in September 2000. A Final EIS/EIR was 

released in April 2001, which was certified by CVWD in May 2001. The EIR/EIS includes 

mitigation measures to avoid and/or compensate for air quality and biological resources 

impacts.

This project involves lining the 23-mile reach of the existing, unlined canal. The canal lining 

project will have temporary air quality impacts in the SSAB associated with construction 

within the proposed right-of-way of the All American Canal. Temporary and permanent 

impacts to desert scrub and sand dune habitat would result from construction activities. 

Special-status species known to inhabit or likely to inhabit these desert habitats are flat-tailed 

horned lizard, Colorado Desert fringe-toed lizard, giant Spanish needles, Peirson’s milkvetch, Wiggin’s croton, sand food, and Andrew’s dune scarab beetle. 

All American Canal Lining: A Final EIS/EIR for the All American Canal Lining Project was 

released in March 1994. The All American Canal Lining Project EIR/EIS includes mitigation 

measures to avoid and/or compensate for air quality and biological resources-related impacts 

to riparian and marsh vegetation, fish in the canal, desert habitat, and special-status species 

associated with desert habitats.

U. S. Border Patrol Activities: The U. S. Border Patrol drives vehicles, grades unpaved 

roads, drags unpaved roads and constructs devises such as cameras to assist in the 

apprehension on undocumented immigrants. These activities can have a negative affect on 

air quality. 
349

4.13 Hazardous Materials

Assumptions And Assessment Guidelines

The assessment of impacts assumes implementation of those measures incorporated into the 

alternatives or required by regulation that avoid or reduce potential adverse impacts. This 

assessment evaluates the potential for the alternatives to result in hazardous materials-related 

impacts to the public or the environment in the vicinity of the ISDRA. An alternative would 

be expected to have an adverse effect if it would:

Create a significant hazard by exposing the public to hazardous materials at levels 

exceeding the range of risk generally considered to be acceptable to EPA or other 

federal or state agencies as a result of being located on or proximate to a known 

hazardous materials site

Create a significant hazard to the public or the environment through the routine 

transport, use, or disposal of hazardous materials

Effects Common To All Alterna tives

The environmental database search discussed in Section 3.13 provided the location of and 

information on known hazardous materials sites or activities that conceivably could cause 

impacts (e.g., direct, indirect, or both) to human health and the environment that are located 

at or near the ISDRA. The ISDRA is located approximately 20 miles from known hazardous 

materials sites so there is an exceedingly low potential for and probability of affecting public 

health and safety due to hazardous materials and wastes. This would be true for all 

alternatives. As a result, specific potential adverse effects associated with these hazardous 

materials sources are not addressed further in this section.

The primary potential source of hazardous materials-related impacts at the ISDRA would 

derive from the short-term use of varying amounts and quantities of materials which typically 

would be associated with OHV and camping related equipment brought onsite by visitors. 

The typical types of hazardous materials used by visitors at the ISDRA include propane, 

gasoline, and oil. The potential hazards typically would include accidental releases of 

propane, fuels, oil, and grease from camping or OHV related equipment or from accidents 

involving the use of flammable materials for cooking. The release of propane would 

dissipate into the air. The release of other materials would most likely be to the sandy soil. 

It is unlikely that a release would impact groundwater, due to the depth to the groundwater 

and the small amount of material that is used by any user. It is also not likely that a release 

would impact the surface water, since the surface water that is near the ISDRA is in a canal 

on one edge of the ISDRA. The amounts of material brought to the ISDRA would be 

expected to vary under different alternatives, primarily due to the number of anticipated 

visitors. The probability of accidental spills of fuels, oil, and grease is expected to be directly 

proportionate to visitation. However, even considering the maximum visitor supply, none of 

the alternatives likely would involve a release greater than de-minimis conditions. Deminimis conditions are those “... that generally do not present a material risk of harm to 
350

public health or the environment and that generally would not be the subject of an 

enforcement action if brought to the attention of appropriate government agencies” (Holland 

and Knight LLP, 2001). 

Mitigation Measures 

BLM will encourage recreational users to be prepared to take the proper response to releases 

of hazardous materials through an education program. The education program will include 

providing information about the potential impact of large spills on the canal system and 

groundwater. ISDRA law enforcement will be trained to provide immediate assessment of 

spills that could impact the canal system and to relay information to the National Spill 

Response system, Imperial Irrigation District, Coachella Valley Water District, and the 

Bureau of Reclamation in the event of a large spill that could impact the canal system. BLM 

will provide education materials relating to the storage, disposal, and use of hazardous 

materials related to OHV recreational use. 

Cumulative Effects

None identified.
351

4.14 Geology and Soils

This section evaluates the potential impacts of Alternatives 1, 2, 3, and 4 on the geology and 

soils, as well as energy and mineral resources of the ISDRA planning area. Assessment 

methods are presented for soil and geologic conditions, seismic activity, and energy and 

mineral resources. Impacts due to seismic activity and related to energy and mineral 

resources are also discussed. 

Assumptions And Assessment Guidelines

Soil and Geologic Conditions

An impact resulting from implementation of an alternative would be considered adverse if it 

does not meet the applicable criteria set forth by regulation, as defined in Title 23, CCR, 

Division 3, Chapter 15, Title 14, CCR, Division 7, and 40 CFR Part 258, Subpart B 

(Location Restrictions), or if an impact would expose people or workers in the ISDRA to 

major geologic hazards. This would include the presence of geologic conditions such as 

unstable or compressible soils and liquefaction that would contribute to the destruction or 

severe damage (e.g., destabilization) of structures during a geologic event and could 

endanger the lives of persons in the ISDRA. In addition, impacts would result if 

implementation of the alternative would affect the continued enjoyment, study, or 

interpretation of a unique geologic feature, either by degrading or limiting access to the 

feature. 

The geologic effect of OHVs on ISDRA has been discussed by Norris (1995), and is 

characterized primarily by increased erosion and the creation of vehicle tracks. Although the 

visual affects of the OHV tracks may dissipate after a windstorm, the lasting effects of the 

vehicle erosion impacts on mobile sand dunes lasts longer. The lasting impact is the lack of 

vegetation and therefore reduced wildlife and insect species. These lasting impacts can be 

repaired naturally in a few years if no further vehicle activities occur in the impacted area. 

Unvegetated or sparsely vegetated dunes are for the most part active, dynamic systems that 

will fairly promptly re-establish their pristine form if left relatively undisturbed and if the 

sources of sand are not adversely affected in some way. Relict or vegetated dunes would 

take longer to recover their original character than mobile, active dunes. Better-developed 

soils and stable surfaces within the Planning Area, particularly those of the distal portions of 

the alluvial fans extending into the Plan Area from the east, would take even longer to regain 

their natural aspect. In these areas of more stable surfaces, soil compaction would also be an 

effect of OHV activities. Evidence would suggest that some of these gravelly, stable surfaces 

might not regain their predisturbance character for centuries (Steiger and Webb, 2000). In 

this light, it is important to note that impact analyses for this EIS refer to a baseline that is the 

current condition of the ISDRA, and current conditions include the plentiful vehicle tracks on 

these desert surfaces in most areas, with the exception of the North Algodones Dunes 

Wilderness Area and the Mammoth Wash Management Area. These tracks are part of the 

current surface geologic conditions of the Recreation Area.
352

Energy and Mineral Resources

An alternative would have an adverse impact on leasable or locatable mineral resources if the 

loss of existing mineral resources could not be offset by domestic reserves. Impacts to 

mineral resources would be considered adverse if the alternative would affect the existing or 

potential future economic production of a mineral resource, either by limiting access to the 

resource or by degrading the quality of the resource. It would also be an adverse effect if 

implementation of the alternative would eliminate access to a potential mineral resource that 

has been determined by a regulating agency to be rare, unique, or regionally significant.

Seismic Hazards

The ISDRA lies within a seismically active area. A seismic hazard in the vicinity of the 

ISDRA planning area would be considered adverse if, as a result of the occurrence of the 

maximum probable earthquake event, structures (i.e., bridges or buildings) built within the 

ISDRA were to fail causing potential injury and property damage. When state and federal 

regulations conflict, the more stringent regulation will be used to establish impact 

significance. Severe seismic hazards would include the presence of an active fault onsite or 

the presence of other geologic conditions that would directly or indirectly endanger the lives 

of persons in the ISDRA.

Effects Common to All Alternatives

Seismic Hazards

In seismically active regions, the potential exists for seismic damage to existing facilities and 

structures. Construction of future facilities and structures is proposed under all alternatives; 

consequently, the potential for seismic damage to current and future construction exists. To 

encourage public safety, any structures or facilities built will be constructed according to 

standard construction codes of practice for structures in the State of California in seismically 

active regions. Implementation of any alternative would not substantially alter the potential 

for seismic impact that exists: no adverse impact would result.

Energy Resources

Lease arrangements for energy and mineral resources could be limited or eliminated to 

minimize the potential of conflicting uses of the ISDRA. Access to portions of the Glamis 

and dunes known geothermal resource areas would not limited, resulting in the potential for 

conflict between OHV use and geothermal development. However, implementation of any 

alternative would not substantially alter the potential for conflict that exists under baseline 

conditions. Therefore, no adverse impact would result.

Mineral Resources

Mining claims and sand and gravel operations will be limited to the Glamis Management 

Area. However, implementation of any alternative would not substantially alter the potential 

for mineral operations that exists under interim management conditions. Therefore, no 

adverse impact would result.
353

Alternative 1

Geology and Soils

The same conditions that applied immediately prior to instituting the temporary closures 

would apply under Alternative 1, the No Action Alternative. A larger area of the ISDRA 

would be open to OHV activity, and use intensity would be greater than under any other 

alternative. Alternative 1 does not consider controls on camping and OHV use in the 

Planning Area, so a larger area is available for recreational use. In addition, Alternative 1 

does not place any limitation on the visitor supply of the ISDRA, so the use intensity would 

be greatest under this alternative. Therefore, erosion impacts resulting from OHV activities 

would be greater for Alternative 1 than under any other alternative. Currently areas of very 

high use show significant impacts due to OHV use. Other areas such as the Adaptive 

Management Area and the Mammoth Wash Area are significantly less impacted. 

Implementation of this alternative could substantially alter the potential for erosion damage 

and soil compaction in the future as the visitor supply increases without limitation. Adverse 

impacts are likely.

Alternative 2

Geology and Soils 

This alternative would open a larger portion of the ISDRA to OHV use than under 

Alternative 3, and less than Alternatives 1 and 4. The Planning Area and Adaptive 

Management Area have use restrictions under this alternative. However, the intensity of use 

allowed in all areas opened to OHV recreational activities would be lower in Alternative 2 

than in Alternative 4, and higher than in Alternative 3. Therefore, the erosion impacts and 

soils compaction would be greater than under Alternative 3 and less than under Alternatives 

1 and 4. The area available for OHV use would be less than existing conditions, and the 

intensity of use would be more constrained. Currently areas of very high use show 

significant impacts due to OHV use. Other areas such as the Adaptive Management Area 

and the Mammoth Wash Area are significantly less impacted. By controlling the future use 

and intensity of use in the less impacted areas, and directing high intensity use to the already 

impacted areas, the potential for additional erosion damage and soil compaction in the future 

should decrease. Therefore, adverse impacts are not anticipated

Alternative 3

Geology and Soils

This alternative would open a smaller area of the ISDRA to OHV use and would limit the 

intensity of that use more than under Alternatives 1, 2, or 4. Therefore, the impact resulting 

from OHV activities, erosion and soil compaction would be less under this alternative than 

under any of the other alternatives. Additionally, use would be directed to the areas that are 

already heavily impacted. Significant adverse impacts are not anticipated. 

Alternative 4

Geology and Soils

This alternative would open a larger portion of the Plan Area to OHV use than under 

Alternatives 2 and 3, and less than under Alternative 1. Furthermore, the intensity of use as 

would be allowed by the ROS classes would be greater under Alternative 4 than under any of 
354

the other action alternatives. Therefore, impacts to soils and erosion would be greater than 

under any of the other action alternatives. Currently areas of very high use show significant 

impacts due to OHV use. Other areas such as the Adaptive Management Area and the 

Mammoth Wash Area are significantly less impacted. By allowing the intensity of use 

identified in this alternative the potential for additional erosion damage and soil compaction 

in the future will increase, especially in the areas that currently are not significantly 

impacted. Therefore, significant adverse impacts are anticipated

Mitigation Measur es

To encourage public safety, any facilities built will be constructed according to construction 

codes of practice for structures in the State of California in seismically active regions. This 

requirement will mitigate for earthquake hazards in the ISDRA.

Cumulative Effects

The U, S. Border Patrol routinely drives throughout the ISDRA to apprehend undocumented 

aliens. This activity contributes to the soil erosion and compaction.

BLM has involvement in several mining operations near the ISDRA: Glamis, Mesquite, and 

community pits. This contributes to cumulative impacts on mineral resources and geology 

and soils.
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CHAPTER 5.0

COORDINATION & CONSULTATION

Public Scoping Meetings

The scoping process for the project was designed to solicit input from stakeholders, the 

public, and other interested parties on the issues related to the development of a revised 

RAMP. The BLM initiated the public involvement in 1998. Subsequent public involvement 

activities were conducted in September 2001.

The BLM conducted three public planning meetings and seven public scoping meetings 

between June 1998 and February 2000 to solicit input from the public. Three subsequent 

scoping meetings were conducted during September 2001. The meetings were held at the 

following locations and dates. The number of attendees at each meeting is noted in 

parentheses for the last public scoping meeting:

Initial Public Planning 

Meetings

Initial Public Scoping 

Meetings

Subsequent Public

Scoping Meetings

1) San Diego, California

June 16, 1998

1) Yuma, Arizona

January 10, 2000

1) El Centro, California 

(50 attendees)

September 6, 2001

2) Phoenix, Arizona

June 22, 1998

2) Long Beach, California

January 12, 2000

2) Phoenix, Arizona

 (300 attendees)

September 25, 2001

3) Anaheim, California

June 30, 1998

3) Cahuilla, California

January 14, 2000

3) San Diego, California 

(400 attendees)

September 27, 2001

4) Phoenix, Arizona

January 25, 2000

5) San Diego, California

January 27, 2000

6) Brawley, California

February 3, 2000

7) El Centro, California

February 7, 2000
358

The initial Notice of Intent (NOI) to Prepare an EIS pursuant to NEPA was published in the 

Federal Register on October 10, 2001. A subsequent NEPA NOI was published for the 

additional scoping meetings conducted in September 2001. Publishing public notices in 

newspapers of general circulation provided additional notification of the action. The public 

scoping meetings were advertised in seven local newspapers: Imperial Valley Press, Desert 

Sun, San Diego Union Tribune, Los Angeles Times, El Sol del Valle, Arizona Republic and 

The Yuma Daily Sun. Other tools used to communicate with interested parties include “The 

Dunes Newsletter” and postcard announcements of meeting dates, the BLM website and the 

NOI publication. 

Public Review of the Draft EIS

The draft EIS and RAMP were released to the public for a 90 day public comment period, 

ending June 28, 2002. During this public review period 6 public meetings were held to 

explain the EIS and RAMP to the public and to allow public comment. The meetings are 

summarized in the table below including approximate number of participants:

Location Date

El Centro, CA

(92 participants)

April 9, 2002

Long Beach, CA

(810 participants)

April 11, 2002

Phoenix, AZ

(720 participants)

April 15, 2002

Brawley, CA

(86 participants)

April 18, 2002

Yuma, AZ

(356 participants)

April 23, 2002

San Diego, CA

(522 participants)

April 25. 2002

In addition, several workshops were held to explain the documents and the review process to 

small groups of the public. No comments were accepted at the workshops.

BLM received 7,339 comments on the draft EIS and RAMP from the public through public 

meetings, electronic letters and paper letters. 2,778 of the public comments were from 

members of the public located in California. 585 were from residents of Arizona. A 

significant number of comments (over 100 each) were also received from residents of 

Colorado, Florida, Illinois, Massachusetts, Michigan, New Jersey, New Mexico, New York, 

Ohio, Oregon, Pennsylvania, Texas, Washington and Wisconsin. Over 1000 unique issues 

were identified from these comments. A copy of the types of issues identified in these letters 

and BLM’s response to these issues is included in Appendix A. A copy of each letter and 

BLM’s response to each issue identified in available from BLM on a cd. 
359

U. S. Fish & Wildlife Service Consultation 

Prior to implementation of an updated management plan, formal consultation with the 

USFWS was completed to determine impacts to species listed as threatened or endangered 

under the federal ESA. Species that are known to occur, or have the potential to occur at the 

ISDRA, which are listed as threatened under the federal ESA, are the Peirson’s milk-vetch 

and desert tortoise. 

Pursuant to Section 7 of the ESA, the USFWS has issued a Biological Opinion for the 

Preferred Alternative, based on an analysis of that alternative as documented in a Biological 

Assessment and with additional information as requested by USFWS.

Consultation with the State Historic Preservation Officer

Formal consultation with the State Historic Preservation Office was initiated by letter in 

accordance with the Programmatic Memorandum of Agreement Among the Advisory

Council on Historic Preservation, the Bureau of Land Management, and the California State 

Historic Preservation Officer Regarding the California Desert Conservation Area (1980), and 

the State Protocol Agreement between the California State Director of the Bureau of Land 

Management and the California State Historic Preservation Officer (1998). 

Consultation with Native Americans

To comply with Executive Orders regarding Government-to-Government relations with 

Native Americans, formal and informal contacts were made with a number of tribal entities. 

Seven Native American tribes with heritage associations with the dunes were contacted in the 

spring of 2002 for the purpose of conducting consultation. The seven Native American tribes 

were: the Quechan tribe, the Colorado River Indian Tribes, the Fort Mojave Indian Tribe, the 

Cocopah Indian Tribe, the eleven Kummeyaay reservations, the Torres-Martinez Desert 

Cahuilla, and the Morongo Band. In concert with consultation, tribal elders and 

representatives of these tribes were interviewed concerning heritage values at the dunes.

BLM commissioned a Cultural Landscape Study of the Imperial Sand Dunes that included 

interviews with elders and representatives of these seven tribes. Members of these tribes 

were interviewed about present and past connections with the dunes to identify traditional 

cultural properties and assess the dunes as a cultural landscape. The results of the interviews 

indicate that the dunes have some cultural significance for contemporary Native Americans, 

but do not meet the criteria set forth under the National Register of Historic Places. All 

groups interviewed expressed concern about damage to the dunes landscape by recreational 

use.
360

Other Consultations

A number of agencies and interests, including local, state and federal have been involved in 

the development of this plan. BLM coordinated with and included any agency that expressed 

an interest in the plan. In addition, BLM’s Desert Advisory Council developed a set of 

resolutions regarding the Imperial Sand Dunes Recreation Area Management Plan in 

December 2001. California Department of Fish and Game and BLM discussed relevant 

issues during the development of this EIS.

Coordination of Comments on the draft EIS

BLM received numerous comments on the draft EIS. A summary of these comments and 

BLM’s response is included in Appendix A. Due to the number of comments, the complete 

set of comments cannot be included in this EIS. A copy of the complete set of comments is 

available on a cd by contacting BLM.
361

CHAPTER 6.0

LIST OF PREPARERS

Draft and Final Environmental Impact Statement

UNITED STATES BUREAU OF LAND MANAGEMENT

Name Title

Discipline/

Expertise

Jan Bedrosian Agency Coordinator Relationship to Other 

Documents

Bob Bower Resource Information 

Specialist

Geographic Information 

Systems

Paul Brink State Wilderness Coordinator Areas of Environmental 

Concern

Mark Conley Outdoor Recreation Planner Off-Highway Vehicle 

Coordinator

Lynnette Elser NEPA Coordinator NEPA Compliance

Writer/Editor

Bob Haggerty Law Enforcement Ranger Law Enforcement and Public 

Safety

Transportation and Traffic

Neil Hamada Recreation Area Manager Recreation and Concessions

Glenn Harris Natural Resources Specialist Air Quality

Margaret Hangan SCEP Archaeologist Cultural Resources

Jim Keeler National OHV Coordinator Recreation

Chris Knauf Natural Resource Specialist Biological Resources / 

Threatened and Endangered 

Species

Noise

Jim Komatinsky Community Planner Public Involvement
362

UNITED STATES BUREAU OF LAND MANAGEMENT

Name Title

Discipline/

Expertise

Lynda Kastoll Realty Specialist Land Use (Right-of-Ways)

Ira Long Off-Highway Vehicle 

Coordinator

Outdoor Recreation Planning

Kevin Marty Geologist Geology and Soils

Jack Mills NEPA Planner NEPA Compliance

Dr. Joan Oxendine Archaeologist Cultural Resources

Chris Roholt BLM California Desert 

Wilderness Coordinator

Areas of Environmental 

Concern

Linda Self Realty Specialist Land Use

Tom Sharkey Outdoor Recreation Planner Recreation

Tim Smith Recreation Lead – State 

Office

Recreation

Roxie Trost Resources Branch Chief Program Manager

Dr. John Willoughby State Botanist Biological Resources / 

Threatened and Endangered 

Species

Gavin Wright Wildlife Biologist Biological Resources / 

Threatened and Endangered 

Species
363

Draft Environmental Impact Statement

CH2M HILL

Name Title Discipline/Expertise

Colleen Bredensteiner GIS Specialist Geographic Information 

Systems

Marcia Carrillo GIS Specialist Geographic Information 

Systems

Mark Cochran Biologist Biological Resources / 

Threatened and Endangered 

Species

Areas of Critical 

Environmental Concern

Elizabeth Cutler Environmental Planner Law Enforcement and Public 

Safety

Farshad Farhang Environmental Planner Noise

Dr. Kathy Freas Senior Biologist Biological Resources / 

Threatened and Endangered 

Species

Kirsten Garrison Environmental Planner NEPA Compliance

Susie Hanson Document Specialist Technical Editing

Wendy Haydon Recreation Specialist Recreation and Concessions

Visual Resources

Tom Peters Senior Project Manager NEPA Compliance

Christine Roberts Project Manager NEPA Compliance

Areas of Critical 

Environmental Concern

Ray Romero Biologist Biological Resources / 

Threatened and Endangered 

Species

Mike Slavick Air Quality Specialist Air Quality

Steve Smith Environmental Planner NEPA Compliance

Environmental Justice
364

CH2M HILL

Name Title Discipline/Expertise

Hazardous Materials

Transportation and Traffic

Diana Sokolove Environmental Planner Cumulative Impacts

Dr. Geof Spaulding Project Manager Water Resources

Cultural Resources

Land Use

Dr. Fatuma Yusuf Environmental Planner Socioeconomics
365

Subconsultants

Name Title

Discipline/

Expertise

ACT

Hon Yow

Traffic Planner Transportation and Traffic

Colorado State University

Dr. Glenn Haas

Professor, Recreation 

Planner

Visitor Capacity and 

Recreation Opportunity 

Spectrum

EDAW

Rebecca Apple

Cultural Resources Specialist Cultural Resources

California State University, 

Chico 

Dr. Laura McLachlin

Professor, Department of 

Recreation and Parks 

Management

Socioeconomics

Dr. Emelyn Sheffield Professor, Department of 

Recreation and Parks 

Management, California 

State University, Chico

Socioeconomics

Environmental Justice

Fred Sproul Biologist Botany
366

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367

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Blank page back
379

CHAPTER 8.0

GLOSSARY AND LIST OF ACRONYMS

AADT or ADT Average Annual Daily Traffic volume

AASHTO Association of American State Highway and Transportation Officers

Access Easement Legal permission granted by the owner of a property to another entity, 

to enter or cross the property for specified purposes. 

ACEC Area of Critical Environmental Concern. An identified area requiring 

special management attention to protect important biological, 

geological, or cultural resources. 

APCD Air Pollution Control District

ASA American Sand Association

AST aboveground storage tank

ASTM American Society for Testing and Materials

ATV All-terrain vehicle. A three- or four-wheeled vehicle equipped with 

low-pressure tires and a seat straddled by the rider.

BA Biological Assessment

Biological Opinion A document prepared by the USFWS and NMFS stating their 

collective opinion as to whether or not a federal action will likely 

jeopardize the continued existence or adversely modify the habitat of a 

listed threatened or endangered species.

BLM Bureau of Land Management

BMP best management practice

BO Biological Opinion

BOR Bureau of Reclamation

CAA Clean Air Act

CAAQS California Ambient Air Quality Standards. California Ambient Air 

Quality Standards established by the California Air Resources Board.

Caltrans California Department of Transportation

Candidate Species A plant or animal species that is undergoing status review by the 

USFWS to be listed as threatened or endangered.

CARB California Air Resources Board

CCR California Code of Regulations

CDCA California Desert Conservation Area Plan. Completed in 1980, this 

Congressionally mandated document provides long-range, general 

guidance for management of all BLM-administered public lands in the 

California Desert, including the Imperial Sand Dunes. 
380

CDFG California Department of Fish and Game

CDPA California Desert Protection Act

CEDD California Economic Development Department

CEQ Council on Environmental Quality

CEQA California Environmental Quality Act

CERCLA Comprehensive, Environmental Response, Compensation, and 

Liability Act

CESA California Endangered Species Act 

CFGC California Fish and Game Commission

CFR Code of Federal Regulations 

cfs cubic feet per second

CHP California Highway Patrol

CIWMA California Integrated Waste Management Act

Class C (Controlled) The most restrictive of the four Desert Plan multiple use classes, 

assigned only to wilderness study areas that have been preliminarily 

recommended as suitable for wilderness designation by Congress. 

Class I (Intensive) Areas where concentrated use of land and resources is intended. 

Includes areas set aside for intensive off-highway vehicle recreation. 

This class is suitable for development of facilities for intensive 

recreational use.

Class L (Limited) Provides for low-intensity, carefully controlled use. Usually assigned 

to areas of particularly sensitive or important natural or cultural 

resources. Facilities that provide for resource protection may be 

constructed in this class.

Class M (Moderate) Intended to provide a balance between resource protection and use. 

Recreation facility developments may be constructed in this class.

CLETS California Law Enforcement Telecommunication System

Closed Area An area where motorized vehicles are not allowed. Nonmotorized 

uses such as hiking and horseback riding are usually allowed and 

encouraged in Closed Areas, except in present and former military 

bombing ranges, which are closed to all forms of human entry. The 

perimeter of all Closed Areas is posted with signs to inform the public 

of the types of uses allowed. 

cm centimeter

CMAGR Chocolate Mountain Aerial Gunnery Range

CNDDB California Natural Diversity Data Base. The CNDDB is a 

computerized inventory of information on the general location and 

condition of California’s rare and threatened animals, plants, and 

natural communities maintained by the CDFG.

CNEL Community Noise Equivalent Level

CNPPA California Native Plant Protection Act

CNPS California Native Plant Society. CNPS is a professional society of 

plant biologists, scientists, and associated professionals that has 

accumulated a statewide database on California native plants and their 

distribution.

CO carbon monoxide
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CRHR California Register of Historical Resources 

Critical Habitat Specific areas with physical or biological features that are imperative 

to the continued survival and conservation of a listed species. These 

areas may require special management and are generally designated in 

Federal Register notices. 

CSLC California State Lands Commission

Cultural Resources Building, district, structure, site, or object significant in history, 

architecture, archaeology, culture, or science.

CVWD Coachella Valley Water District

dB decibel

dBA decibel A-weighted

DEIR Draft Environmental Impact Report

DEIS Draft Environmental Impact Statement

DOI Department of Interior

DOT Department of Transportation

EA Environmental Assessment. A document prepared to predict and 

evaluate the effect of an action on the natural environment and human 

communities.

EDD Employment Development Department

EDR Electronic database report

EIS Environmental Impact Statement. A federal environmental decision 

making report prepared pursuant to the National Environmental Policy 

Act (NEPA).

EIS/EIR Environmental Impact Statement/Environmental Impact Report

EMS emergency medical service

Endangered Species An animal or plant species that is in danger of extinction throughout 

all of a significant portion of its range (as defined in The Endangered 

Species Act Amendments of 1982). The U.S. Fish and Wildlife 

Service regularly use this definition. The State of California and the 

California Native Plant Society subscribe to a slightly different 

definition. 

Endemic Native to a certain region.

EPA United States Environmental Protection Agency

EQIP Environmental Quality Incentives Program

ERNS Emergency Response Notification System

ESA Endangered Species Act 

Eutrophication The process by which waters rich in mineral and organic nutrients 

promote a proliferation of plant life, especially algae, and reduce the 

dissolved oxygen content, causing the extinction of other organisms.

Existing Setting Existing biological, physical, social, and economic conditions of an 

area to which changes are proposed, either directly or indirectly, by 

human actions.

FERC Federal Energy Regulatory Commission
382

FESA Federal Endangered Species Act

FICC Federal Interagency Communication Center

FINDS Faculty Index System

FLPMA Federal Land Policy Management Act of 1976. The Congressional 

Act that directs BLM to manage the public lands according to the 

principles of multiple use and sustained yield. The California Desert 

Conservation Area and the development of the Desert Plan resulted 

from Section 601. Section 603 required the BLM to review roadless 

areas for potential inclusion in the National Wilderness Preservation 

System, and mandated interim management protection of wilderness 

study areas.

Gateway Gateway of the Americas Specific Plan Area

GIS geographic information system

GPS global positioning system

Green Sticker Fund A fund generated by the State of California through collection of offhighway vehicle “green sticker” registration fees, 1 percent of state 

gasoline taxes, and fines from violations at State Vehicular Recreation 

Areas. Grants from the fund are made available to federal, state, and 

local governmental entities to acquire, develop, operate, and maintain 

OHV recreation areas. 

Green Sticker Evidence of registration with the State of California Department of 

Motor Vehicles. All OHVs are required to display it. 

GWSI Groundwater Site Inventory

Habitat (1) – Specific parameters of physical conditions used by a single 

species, a group of species, or a large community. The major 

components of habitat are generally considered to be food, water, 

cover, and living space. (2) – The natural living space of an organism. 

HCM Highway Capacity Manual

Interstate

ICAPCD Imperial County Air Pollution Control District

ICO issue, concern, and opportunity

IID Imperial Irrigation District

ISDRA Imperial Sand Dunes Recreation Area

Known Geothermal An area in which the geology, nearby discoveries, competitive

Resource Area interest, or other evidence would, in the opinion of the Secretary of the 

Interior, convince those with experience in the field that the prospects 

for extraction of geothermal steam or associated geothermal resources 

are good enough to warrant expenditures of money for that purpose. 

Major portions of the Glamis KGRA and the Dunes KGRA overlap 

the Imperial Sand Dunes Recreation Area. 

kV kilovolt
383

Lead Agency The agency initiating and overseeing the preparation of an EIS and/or 

EIR.

LEO Law enforcement officer. LEO in the BLM responsible for protecting 

public safety and resources within the United States’ 264 million acres 

of BLM-managed public land.

Limited Use Area An area in which motor vehicles are restricted to approved routes. 

Restrictions may vary among individual Limited Use Areas.

LOS Level of Service existing for roadway segments.

MBTA Migratory Bird Treaty Act

Metropolitan Metropolitan Water District of Southern California

MOU Memorandum of Understanding 

mph miles per hour

MUC multiple use classification. A classification system developed as part 

of the Desert Plan, with guidelines describing the types of land uses 

and resource management techniques appropriate to each class. Most 

lands in the California Desert Conservation Area have been assigned 

to one of the four multiple use classes: Class C, L, M, or I. Small 

acreages, notably those proposed for sales or withdrawal to other 

agencies, remain unclassified.

NAAQS National Ambient Air Quality Standards. EPA established the 

NAAQS to protect public health and welfare from the effects of air 

pollution.

NCIC National Crime Information Center

NECO Northern and Eastern Colorado Desert Coordinated Ecosystem 

Management Plan

NEMO Northern and Eastern Colorado Coordinated Management Plan

NEMO Plan Northern and Eastern Mojave Plan

NEPA National Environmental Policy Act 

NESHAPS National Emissions Standards for Hazardous Air Pollutants. The 

federal and state laws and regulations define a group of pollutants 

called “hazardous air pollutants,” “toxic air contaminants,” or “air 

toxics.” These pollutants are regulated by the NESHAPS section of 

the federal Clean Air Act, various state laws and regulations, state air 

toxics acts (e.g., AB 1807, AB 2588, and SB 1731 programs), and 

Imperial County Air Pollution Control District (APCD) Regulations 

XI and XII.

NHPA National Historical Preservation Act

NLETS National Law Enforcement Telecommunication System

NO2 nitrogen dioxide

NOI Notice of Intent 

NOP Notice of Preparation

NOx oxides of nitrogen

NPA National Programmatic Agreement

NPS National Park Service

NRHP National Register of Historic Places
384

O3 ozone

OHV Designation Public lands designated for off-highway vehicle use. Lands in the 

California Desert Conservation Area are designated as “Open,” 

“Closed,” or “Limited” for OHV use. 

OHV Off-highway Vehicle. A general term referring to all types of vehicles 

capable of operating on roads that are not maintained. These include 

motorcycles, ATVs, dune buggies, and four-wheel-drive vehicles. 

Open Area A place in which motor vehicles may travel freely (i.e., cross-country 

travel is permitted).

P Primitive. An ROS class designation that characterizes an area as an 

essentially unmodified natural environment of fairly large size.

Pb Chemical notation for lead.

Plank Road A one-lane wooden road that was the first automobile thoroughfare to 

cross the Imperial Sand Dunes between 1914 and 1926. Remnants of 

the Plank Road are now designated as an Area of Critical 

Environmental Concern (ACEC). 

PM10 respirable particulate matter with a diameter of less than 10 microns

PRC Public Resources Code

R Rural

RAMP Recreation Area Management Plan. A plan prepared for recreation 

areas requiring special management.

RCRA Resource Conservation and Recovery Act

RN Roaded-Natural. An ROS class designation characterizing an area as a 

predominantly natural-appearing environment with moderate evidence 

of the sights and sounds of humans.

ROD Record of Decision

ROG reactive organic gas

ROS Recreation Opportunity Spectrum. A land delineation system 

commonly used by federal land management agencies to address the 

need for a range of recreational opportunities within their planning 

areas.

Rural (R) An ROS class designation that characterizes a natural environment that 

has been modified substantially by development of structures, 

vegetative manipulation, or pastoral agricultural development.

RV Recreational Vehicle. Categorically, this term describes large, selfcontained camping vehicles such as motorhomes and travel trailers.

SARA Superfund Amendments and Reauthorization Act

SCAQMD South Coast Air Quality Management District

SDAB San Diego Air Basin

SDCWA San Diego County Water Authority

Semi-Primitive Motorized (SPM). An ROS class designation that characterizes an area as 

a predominantly natural or natural-appearing environment of moderate 
385

to large size. Use of local primitive or collector roads with 

predominantly natural surfaces and trails suitable for motorbikes is 

permitted.

Semi-Primitive Non-Motorized (SPNM). An ROS class designation that 

characterizes an area as a predominantly natural or natural-appearing 

environment of moderate to large size. Motorized recreation use is not 

permitted.

SHPO State Historic Preservation Officer

SIP State Implementation Plan

SO2 sulfur dioxide

SOx sulfur oxide

SPM Semi-Primitive Motorized

SPNM Semi-Primitive Non-Motorized

SR State Route

SSAB Salton Sea Air Basin

T&E species Threatened and endangered species. This broad definition is 

considered when writing and implementing policy. 

T/E threatened/endangered

TCP Traffic Control Plan

Threatened Species An animal or plant species that is likely to become endangered within 

the foreseeable future throughout all or a significant portion of its 

range (as defined in the Endangered Species Act Amendments of 

1982). This is the definition used by the U.S. Fish and Wildlife 

Service. The State of California and the California Native Plant 

Society define the term slightly differently. 

TOA Thomas Olsen and Associates

TRT technical review team

U Urban

Urban (U) A ROS class designation characterizing an area as a substantially 

urbanized environment, although the background may have naturalappearing elements.

URTD upper respiratory tract disease

USACE United States Army Corps of Engineers

USBP United States Border Patrol

USC United States Code

USFS United States Forest Service

USFWS United States Fish and Wildlife Service

USGS United States Geological Survey

USMC United States Marine Corps

UST underground storage tank

Visitor Supply Maximum number of visitors that could occur at ISDRA while 

maintaining the designated ROS class.
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VRM Program Visual Resource Management Program. A BLM-developed 

system used to evaluate the visual resources of a given area to 

determine what degree of protection, rehabilitation, or enhancement is 

desirable and possible.

VUD Visitor Use Day. One VUD is equal to 12 hours spent by one person 

in the pursuit of recreation.

WEMO West Mojave Coordinated Management Plan

West Mojave Plan West Mojave Habitat Conservation Plan

WHA wildlife habitat area

Whoop-De-Do’s A series of closely spaced undulations in the surface of an off-highway 

vehicle trail, created by the tires of the vehicles. Whoop-de-do’s make 

the trail difficult to use for some types of vehicle, particularly large 

RVs. 

WIS Wilderness Implementation Strategy

WSA Wilderness Study Area. A roadless area of public lands that the BLM 

has determined possess the wilderness qualities described in the 

Wilderness Act of 1964. Congress established WSAs to study the 

suitability of areas of possible designation as wilderness. 
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APPENDIX A

PUBLIC COMMENTS AND RESPONSES 

SUMMARY

Public Review of DEIS

On March 28, 2002, BLM released for public comment a Draft Environmental Impact 

Statement (DEIS) which would amend the California Desert Conservation Area (CDCA) 

Plan by revising the Imperial Sand Dunes Recreation Area RAMP. The BLM published a 

DEIS analyzing alternative management strategies which could be employed in the revised 

RAMP, as well as a Proposed RAMP embodying BLM’s preferred alternative. The BLM 

requested public comment on the DEIS and proposed RAMP over a 90-day period which 

ended on June 28, 2002. In addition, BLM provided overviews and workshops on the DEIS 

to individuals, interest groups, local governments, BLM’s Desert Advisory Council, and 

tribal councils. BLM initiated consultation with the Quechan and six other tribes and 

commissioned a Cultural Landscape Study of the Imperial Sand Dunes that included 

interviews with elders and representatives of these tribes. 

Notice of the public review period was published in the Federal Register on March 29, 2002, 

by the Environmental Protection Agency. The public was notified of the following dates and 

venues for public meetings through news releases, public service announcements, and the 

BLM California and El Centro Field Office websites. Public comments were received at 

these meetings and were recorded by court reporters. The public meetings were held 

between the hours of 7:00 p.m. and 10:00 p.m. local time on the following dates at the 

following locations:

April 9, 2002 El Centro, CA

City Council Chambers

1275 Main Street

El Centro, CA

April 11, 2002 Long Beach, CA

The Grand

4101 East Willow Street

Long Beach, CA
4

April 15, 2002 Phoenix, AZ

Phoenix College

1202 West Thomas Road

Phoenix, AZ

April 18, 2002 Brawley, CA

City Council Meeting Room

225 A Street

Brawley, CA

April 23, 2002 Yuma, AZ

Yuma Civic and Convention Center

1440 W Desert Hills Drive

Yuma, AZ 

April 25, 2002 San Diego, CA

Marriott Mission Valley

8757 Rio San Diego Drive

San Diego, CA

Public Comments Analysis

Over 7,350 responses were received through oral testimony or written correspondence during 

the comment period. The U.S. Forest Service (USFS) Content Analysis Team (CAT) was 

contracted to analyze and synthesize public comments into concise “public concern” 

statements. This information was then organized in a report designed to provide a narrative 

summary of comments and a comprehensive list of public concerns raised during the 

comment period. The public concern list identifies specific requests and common themes 

expressed by individuals and groups. These requests and themes are organized into a 

condensed format to facilitate the BLM’s review of public sentiments and identify possible 

actions. One or more illustrative sample statements accompany each public concern. Sample 

statements support the public concerns, and may also impart the author’s suggestion(s) on 

how, when, or where the concern should be addressed. Moreover, it should be noted that 

sample statements are just that— samples. Any given public concern may be supported by 

only one or as many as several thousands of supporting comments. Only those comments that 

offer significant variations of a public concern are noted.

The Content Analysis Team documented and analyzed public comments on the ISDRA DEIS 

using a process called “content analysis.” This process provides a systematic method of 

compiling and categorizing the full range of public viewpoints and concerns. Content 

analysis is intended to facilitate good decision-making by helping the planning team to 
5

clarify, adjust, or incorporate technical information in preparing the FEIS/Proposed RAMP. 

In the analysis process, each response (letter, verbal testimony, etc.) was given a unique 

identifying number, which allows analysts to link specific comments to original letters. 

Respondents’ names and addresses were then entered into a project-specific database 

program, enabling the creation of a complete mailing list of all respondents. The database is 

also used to track pertinent demographic information, such as federal, state, tribal, county, 

and local governments or government associations; business and industry groups; 

recreational organizations; and preservation, conservation and multiple use organizations.

BLM’s project management personnel reviewed the list of public concern statements and 

associated sample statements and assigned appropriate staff to each public concern. In 

making these assignments it became clear that some of the public concerns could be 

combined. Assigned staff evaluated the public concern statements and associated sample 

statements. They made revisions to the FEIS and Proposed RAMP as appropriate, and 

prepared written response to public concern statements that are presented below. The BLM 

staff who responded to the public concerns evaluated each public concern of its merit and did 

not know how many people shared any particular public concern. It is important for the 

public and project team members to understand that this process does not treat comments as 

votes and thus cannot sway decision makers toward the opinion of individuals, groups, or 

pluralities. Content analysis ensures that every comment is considered with equal merit in 

the decision process.

Responses to public concerns are provided below. In reviewing the public concerns and 

responses, readers should note the following:

- To the extent that two or more public concern statements are the same or very similar, 

the comments are grouped together and addressed in one response.

- For public concern statements that were characterized as applause, no response was 

prepared.

- For comments which only cast a preference for a particular alternative or proposal 

with no justification, no response was prepared.

- For public concern statements for areas well beyond the geographic range of this plan 

and/or subjects not pertinent to this plan, no response was prepared.

The large number of responses received made it impractical to publish every single public 

concern or comment submitted in this document. BLM attempted to include representative 

public concerns and comments on all major subjects in this summary. Redundant material 

was not included to assist readability and maintaining a manageable size to the FEIS. A 

complete list of public concerns, comments and BLM responses is available from BLM by 

request.

The public concern statements that follow are grouped by general subject. Choice was 

necessary in placing some statements into groups. Therefore, the reader is encouraged to 

review all the groupings to fully understand public concerns on particular subjects. It should 

be noted that the public concern statements that follow are a representative summary only 
6

and do not represent all public concerns or all public comments submitted. The subject 

groups are:

- Planning and Management

- Endangered Species Act and Affected Environment

- Visitor Use

- Vendors

- Law Enforcement

- Infrastructure

Responses to Public Comments

Planning and Management 

#1 Public Concern: The BLM should prioritize multiple -use management, balance all 

values and uses, and ensure the public’s right to access public lands.

Public Comment: Keep as much land open to recreation as possible. This will 

actually lead to lower levels of impact. I support a sensible multiple use philosophy 

that allows for responsible motorized travel. Closures are a bad choice. More 

managed land for recreational use is the prudent choice. (#783)

Public Comment: Making areas off-limits, shutting down areas at times of the day 

and night, limiting campsite size, requiring permits— this has no effect on the 

biodiversity of this area. This is only about a socialistic land grab to restrict public 

rights to public land. This is public land. Public access is what is needed. (#5853)

Public Comment: Efforts by environmental, whacko extremists to close the Imperial 

Dunes area to off-road vehicle use is nothing more than another effort by these 

people to lock the public out of public lands! As members of the "public," people who 

drive off-road vehicles in this area have every right to use the land for legitimate 

recreational purposes! So far as I can determine, off-road vehicle use poses no 

substantive threat to any plant or animal in this area. In fact, Imperial Dunes is one 

of the few areas where people can pursue the legitimate recreation of driving off-road 

in a way which is both safe to people and the environment. I urge you to do 

everything possible to open all of the Imperial Dunes area to the public for vehicular 

recreational use. The "public" has a right to use "public" lands! (#8204)

Public Comment: Why is BLM calling this plan a Recreation Area Management 

Plan? The dunes are more than just recreation. They are also a natural environment. 

BLM should do a more general management plan that balances all aspects of 

management, including natural values, rather than favoring recreation. (#5844)

Public Comment: The BLM should provide the maximum amount of recreation 

opportunities that the natural resources will allow. Camping and OHV use should be 

encouraged and supported with adequate facilities. (#7941)
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BLM Response: The Federal Land Policy Act requires BLM to use and observe the 

principles of multiple use in developing land use plans for public lands. Multiple use is a 

concept that requires that public lands and their resource values be managed in a way that 

best meets the present and future needs of the people. Multiple use involves a combination 

of balanced and diverse resource uses that takes into account the long-term needs of future 

generations for renewable and nonrenewable resources. BLM will manage the ISDRA for 

wilderness, conservation of species and habitats, OHV recreation and a variety of recreation 

programs. 

#2 Public Concern: The BLM's Preferred Alternative for managing the ISDRA should 

be consistent with the environmental protection emphasis of the California Desert 

Conservation Area Plan.

Public Comment : BLM's preferred alternative is also the contrary of the California 

Desert Conservation Area (CDCA) Plan Recreation Element, as summarized on 

pages 3-3 to 3-4 of the DEIS. The CDCA Plan speaks of "emphasizing dispersed 

undeveloped use," a "minimum of recreation facilities," and "protect desert 

resources," hardly the recreation emphasis of the proposed action; thus the proposed 

action is inconsistent with the CDCA Plan guidance for recreation. (#8009)

Public Comment: It is not appropriate for BLM to reopen the closed areas to ORV 

activity. BLM must comply with the California Desert Conservation Area Plan and 

FLPMA. The ISDRA must be managed to afford protection to the desert's fragile 

ecosystems, and to prevent "undue degradation." (#8051)

BLM Response: BLM believes the Preferred Alternative is consistent with the California 

Desert Conservation Plan and largely reflects decisions made in the California Desert 

Conservation Area Plan over 20 years ago. During preparation of the Desert Plan, BLM 

assigned “Multiple-Use Classes” to the recreation area. The classes are based on resource 

sensitivity and types of users in the area. Much of the recreation area was identified as 

“Intensive Use” which provides for concentrated use of land and resources to meet human 

needs. Recreation activities involving high densities are permitted.

#3 Public Concern: The BLM should develop alternatives that emphasize the benefits 

of OHV closures.

Public Comment : We recommend that the BLM develop a new range of reasonable 

alternatives based on a redrafted Purpose and Need that provide a more intensive 

role for ORV closures and properly emphasizes the various benefits that accrue to the 

land and the public from such closures. (#8052)

BLM Response: The Federal Land Policy Act requires BLM to use and observe the 

principles of multiple use in developing land use plans for public lands. Multiple use is a 

concept that requires that public lands and their resource values be managed in a way that 

best meets the present and future needs of the people. Multiple use involves a combination 

of balanced and diverse resource uses that takes into account the long-term needs of future 

generations for renewable and nonrenewable resources. BLM will manage the ISDRA for 
8

resource conservation, and meeting the current and future recreational use needs. 

Alternatives which emphasis the benefits of OHV closure were included in the analysis.

#4 Public Concern: The BLM should not open additional areas to OHV recreation.

Public Comment : I would like to voice my opinion against expansion of OHV use of 

the dunes. The fact that some dunes users recklessly break existing rules, and either 

use or threaten violence against enforcement personnel and others, shows that they 

cannot be trusted to abide by any agreements, and do not deserve any expansion of 

their so-called "rights" to drive on the dunes. The concept of ecosystem preservation 

is a well-established and widely accepted principle whose merit is self-evident in this 

case. (#941)

BLM Response: The preferred alternative in the EIS decreases the amount of open OHV 

area and camping area as compared to the no action alternative. The temporary closures 

agreed to in November 2000, received concurrence with the understanding that the RAMP 

and EIS would address the special status species issues. In order to meet the BLM’s multiple 

use mandate, public lands in the ISDRA will be managed as open, limited, closed, and 

designated under a range of classes from the recreation opportunity spectrum. These 

multiple designations allow BLM to provide a quality motorized and non-motorized

recreational experience, as well as meet its conservation goals and requirements. 

#5 Public Concern: The Final EIS should address the environmental impacts that 

might require more restrictive recre ational use levels.

Public Comment : In terms of environmental documentation, we believe the EIS 

would benefit from a more detailed discussion of potential consequences that will 

occur if proposed use levels are exceeded or monitoring identifies a need for more 

restrictive management to protect a particular resource. The information provided is 

vague on this point, often referring to actions to be considered rather than identifying 

specific thresholds or consequences. (#8047)

BLM Response: Management of visitor supply can occur whenever the identified goals of 

the ISDRA are not met. These goals range from the protection of sensitive, threatened and 

endangered species, air quality, soil and water quality, law enforcement and health and 

safety, natural and scenic values, and meeting multiple use and recreation experience 

objectives. Biological and recreational thresholds and trigger resets have been identified in 

the FEIS that will determine specific actions that may restrict recreational use if triggered. 

Appendix B provides the methodology to monitor species of concern in the ISDRA. Primary 

goals for the ISDRA regarding biological resources include the maintenance of viable 

populations of all native species and maintaining habitat connectivity throughout the ISDRA. 

Visitor supply will be closely monitored and managed using the ROS system and multiple 

land use designations and management areas. The visitor capacities identified in the FEIS 

are based on the amount of visitors the various management areas can sustain and continue to 

meet ROS objectives. Should use increase to the point that the 15% or 20% triggers are 

activated, actions shall be taken to ensure ROS management objectives are met. Actions 

considered may include limiting access to the ISDRA or management areas and better 
9

educating and dispersing visitor use to non-peak periods. Extensive monitoring of natural 

and biological resources, health and safety, recreation experiences, and the amount and 

distribution of visitors will allow BLM to effectively manage the ISDRA (see Appendix B of 

the FEIS to review the monitoring plan and how BLM will manage visitor use).

#6 Public Concern: The BLM should not consider the current condition of the ISDRA 

to represent baseline geological conditions.

Public Comment: EPA is also concerned about continuing habitat degradation, 

habitat fragmentation, and wilderness trespass associated with OHV use. We 

commend BLM for proposing strategies to address these issues through ROS 

designations and increased law enforcement, but we believe that the BLM has missed 

an opportunity to propose specific restoration activities to address past impacts, such 

as rutting, which continue to degrade the environment and invite future degradation. 

We note that the DEIS (at page 4-105) treats the current condition of the ISDRA, 

including a plentiful vehicle tracks on these desert surfaces in most areas to be part 

of the baseline geologic conditions. (#8047)

BLM Response: Existing conditions of the ISDRA, which may contain vehicle tracks in 

open areas, have been used to represent baseline conditions. The natural restoration time of 

vehicle impacts on sand dunes can vary greatly depending on a number of conditions. Sand 

does not compact significantly (heavy equipment would normally cause more compaction 

than vehicles commonly used in the Dunes). The recovery of sandy areas used by vehicles 

can be relatively quick, as demonstrated by the closed area near Buttercup.

#7 Public Concern: The BLM should acknowledge that the time it takes for the 

natural restoration of sand dunes can vary.

Public Comment : The assumption of; "Vehicle erosion impacts on mobile sand 

dunes can be repaired naturally in a few years if no further vehicle activities occur in 

the impacted area." This statement we believe is false, a mobile sand dune can be 

repaired in hours with a good strong wind, not years. (#8298)

Public Comment: A hobby is only a hobby, but a habitat is a livelihood for many 

things. The compaction damage from one ride, off the trails, on a dirt bike on your 

standard upland desert can take years to heal, and that can only occur if the riders 

are removed. The ecosystem and geology in the dunes are much more fragile. We 

loved to ride, but stopped when we realized too many careless, or uncaring riders 

only rode for speed and not for enjoyment of the desert and the sport. (#265)

BLM Response: The natural restoration time of vehicle impacts on sand dunes can vary 

greatly depending on a number of conditions. A good example of this is the presently closed 

area near Buttercup. Sand does not compact like clay/silt and vehicle marks will diminish 

naturally (typically within months, not years, under normal conditions).
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#8 Public Concern: The BLM should address the cumulative impacts of drought and 

increased water consumption.

Public Comment : According to the BLM, "the chief impacts on water resources 

resulting from enactment of any of the alternatives would be to increase or decrease 

water supply demand by visitors to the ISDRA." The BLM never addresses the 

cumulative impact of drought and increased visitor water consumption there. 

(#8051)

BLM Response: All water used by visitors is brought in from outside the ISDRA. Water is 

not available to visitors within the ISDRA. Water withdrawals are limited to a small amount 

of non-potable water at the Cahuilla Ranger Station. 

#9 Public Concern: The BLM should recognize that displacing OHV impacts to other 

ecosystems would cause far more environmental damage than to the ISDRA.

Public Comment : In attending most of the desert planning meetings over the past 23 

years, there is one major issue that has received little or no attention. That issue is: If 

the desert areas are closed, where will the 250,000 or more current users go and 

what environmental damage will they cause in these other areas? It is my firm belief 

that the consequences to other areas will be much greater than the minimal damage 

now occurring in the desert, especially at Glamis. Please consider the impact of 

displacing the 249,000 responsible users as well as the 1,000 abusers. I have 

suggested to the "environmentalists" that these people will have a much greater 

negative impact on the beaches and forests than they do on the Glamis area. If the 

1,000 abusers are displaced, they will surely create ten or one hundred times the 

environmental damage to other more environmentally sensitive area. The desert for 

the most part doesn't burn, the forests do! There are only a few plants and animals 

that may be environmentally affected by the abusers in the desert, but think of the 

major impact in other areas. While discussing this with an apparent environmental 

leader at a BLM meeting, the environmentalist brought up an even more compelling 

argument, that they are concerned about the impact of displacing the abusers to Baja 

California. Imagine the impact they will have there with virtually no law enforcement 

and vast areas to destroy that won't be discovered for a long time due to the 

remoteness. (#7829)

BLM Response: Cumulative impacts have been rewritten in the FEIS to reflect OHV 

displacement. The FEIS would sustain the current use at or near levels during the past year. 

Limitations on use are not unique to the BLM. The National Park Service, Forest Service, as 

well as various state agencies, may place limits on any given recreation area that is intended 

to protect resources and allow quality recreation at the same time. The FEIS only addresses 

the ISDRA.

#10 Public Concern: The BLM should consider the increased use of four -stroke 

vehicles in air quality data reports.

Public Comment : We have invested a lot of time and money into our desert 

equipment. We made sure to buy four-stroke vehicles that are very environmentally 
11

friendly. Your report states that the air quality is poor (4-101, Section 4.11, Air 

Quality) yet it is based on old two-stoke vehicles and not what is currently being sold 

today. (#7880)

BLM Response: BLM recognizes that four-stroke vehicles emit significantly less engine 

emissions. The impacts identified in the FEIS represent a worst-case scenario. 

#11 Public Concern: The revised RAMP should address air pollution statistics from 

adjacent agriculture and non -OHV contributors.

Public Comment : The pollutants contained within the dust swirled up by tires of 

various types of off-highway vehicles are not solely . . . from the vehicles operated by 

the recreationists that typically utilize the ISDRA. This is another fact that is hidden 

by the skewed figures and misrepresentation within the RAMP and supporting 

documentation. In 1975, when driving at speed through the dunes, you rarely saw 

dust. Now, with over 30 years of west to east winds blowing topsoil and agricultural 

products from the El Centro and Bakersfield farms, and the ash from crop fires and 

local industries, particles contained within rain, and the dust created from 

construction projects within the surrounding region; you see dust regularly. This also 

adds to the quantity and type of vegetation growing within the ISDRA. As a 

comparison, you can go to the Oregon Sand Dunes, which has no agricultural areas 

within the regular air patterns; though the area is concentrated, and has more 

vegetation, you see little dust at the driest times of year. The amount of dust and 

pollutants that can be attributed to agriculture and non-OHV contributors needs to be 

addressed and compared for these statistics to be fair and accurate. (#7243)

BLM Response: BLM agrees that air quality is an important issue that needs to be 

addressed through joint efforts. BLM is cooperating with the Imperial County Air Pollution 

Control District and EPA to develop an effective air quality monitoring plan. 

#12 Public Concern: The BLM should develop a management plan that is simpler and 

easier to implement than the proposed Recreation Opportunity Spectrum s ystem.

Public Comment : The ROS classification system is difficult to understand and will 

make the RAMP difficult to administer by future BLM Field Office Managers. The use 

of the term demand to characterize the capability to provide for recreation visitors is 

difficult to understand and needs to be corrected. (#1069)

BLM Response: In order to meet the BLM’s multiple use mandate, public lands in the 

ISDRA are proposed to be managed with the preferred alternative as rural, roaded natural, 

semi-primitive motorized, and semi-primitive non-motorized under a range of classes from 

the Recreation Opportunity Spectrum (ROS). These multiple designations allow the BLM to 

provide a quality motorized and non-motorized recreational experience, as well as meet our 

conservation goals. The ROS model is universally used throughout all land management 

agencies in the U.S and has been used for the past 20 years in land management plans. BLM 

sponsored a ROS workshop in the spring of 2002 to help answer questions regarding ROS in 

the DEIS and feels that ROS is an important tool that will enhance the recreation experience.
12

#13 Public Concern: The BLM should use existing multiple -use classes rather than the 

Recreation Opportunity Spectrum.

Public Comment : The CDCA plan established "Multiple-Use Classes" to manage 

the desert. "The classes are based on resource sensitivity and types of uses in the 

area," (1987 RAMP page 5). "The CDCA Plan establishes four multiple-use classes, 

multiple-use class guidelines, and plan elements for specific resources or activities 

such as motorized-vehicle access, recreation, and vegetation," (page 1-6, DEIS). We 

see no reason to change this process. In the preferred Alternative (2) there are only 

four of the six ROS designations used. All being basically the same other than 

wording from the Multiple-Use Classes. In the California Desert Conservation Area 

plan (CDCA) there are four established multiple-use classes. . . . These classes are 

basically the same, just different wording but accomplish the same thing. We see no 

reason for the ROS classes other than to set capacity limits on camping. (#8298)

BLM Response: The California Desert (CDCA) Plan designated the ISDRA and several 

other areas for intensive OHV use. The 1987 RAMP provided guidance for management of 

the dunes based on the amount of use and current information regarding natural and cultural 

resources. This plan update was necessary because of changes in the numbers and types of 

use and additional information regarding natural and cultural resources. 

The ROS system was developed by the U.S. Forest Service in 1979 and is widely used in 

North America. The system is an organizing framework for setting recreation management 

goals. The ROS system is based on the idea that recreationists can realize desired 

experiences by participating in recreation activities in chosen settings. These opportunities 

for activities, settings and experiences range from primitive to urban. The ROS identifies, 

delineates, classifies and categorizes areas into classes based on factors such as remoteness, 

size and evidence of human activity. It also provides information about existing recreation 

opportunities to land use planners and resource managers to assist them in making decisions 

on appropriate land uses, resource development objectives and management prescriptions. 

(Recreation Opportunity Spectrum Procedures and Standards Manual, Ministry of Forests, 

1998).

In order to meet the BLM’s multiple use mandate, public lands in the ISDRA are proposed to 

be managed with the preferred alternative as rural, roaded natural, semi-primitive motorized, 

and semi-primitive non-motorized under a range of classes from the Recreation Opportunity 

Spectrum (ROS). These multiple designations allow the BLM to provide a quality motorized 

and non-motorized recreational experience, as well as meet our conservation goals. The 

ROS model is universally used throughout all land management agencies in the U.S and has 

been used for the past 20 years in land management plans. BLM sponsored a ROS workshop 

in the spring of 2002 to help answer questions regarding ROS in the DEIS and feels that ROS 

is an important tool that will enhance the recreation experience. The FEIS has a table in 

Chapter 2 that shows a comparison between ROS and MUC classes.
13

#14 Public Concern: The BLM should not utilize the Recreation Opportunity 

Spectrum to limit OHV use at the ISDRA.

Public Comment : The American Sand Association adamantly opposes the 

implementation of ROS and its application to limit motorized recreation use at the 

ISDRA. There is no scientific data to support the use of ROS as a method to limit 

motorized activity to protect any natural or cultural resources in the ISDRA. In fact, 

almost every study undertaken by the BLM indicates the opposite. Dune enthusiasts at 

the ISDRA are already [enjoying satisfying experiences in a preferred setting, as 

described in the ROS User's Guide]. Therefore, ROS concepts do not need to be 

applied to the ISDRA unless the intent is to provide a greater number of satisfying 

experiences while providing for conservation. This can be applied to the need for 

more camping and staging areas. (#7226)

Public Comment: The ISDRA boundary should be left as it was before the closures 

and not divided into nine sections (see figure 3.1-2). The central portions of the dunes 

rarely get any use, and I have been going to the dunes for over 22 years, and have 

used all parts of the dunes. If you divide up the dunes and get the people in just high 

use areas you are making the dunes unsafe, too many people in the same place, 

instead of spread out over the dunes. If you limit or restrict visitor use it is not fair to 

the public that owns the land. . . . There should be no ROS classification. (#5899)

BLM Response: The ROS is not being used to limit use. It should be understood that ROS 

is a recreation planning tool. The ROS tool helps recreation planners identify actions that 

will lead to a desired recreational experience. In this instance ROS was utilized to define 

eight geographic areas that lend themselves to providing varying recreational experiences 

based in part on the amount of developments, services, and the number of visitors within the 

areas. In this way a continuum of recreational expectations can be provided for throughout 

the ISDRA. Utilizing ROS does not limit the number of visitors that can recreate in an area. 

Rather, ROS allows managers to identify the amount of area and facilities that are required to 

accommodate a certain number of visitors at a given recreational experience level. Current 

identified capacities will not reduce the number of visitors currently recreating at the ISDRA.

#15 Public Concern: The revised RAMP should not implement the Recreation 

Opportunity Spectrum because the "No Action Alternative " will adequately preserve 

opportunities for low -intensity OHV use.

Public Comment : "The ROS classification of the adaptive management area is 

expected to slightly increase overall OHV related visitor use relative to the baseline." 

"Implementation of this alternative would allow the same to a little more intense use 

than the adaptive management area when compared to the baseline condition." The 

two preceding statements imply that OHV impact will increase within the adaptive 

management area when compared to the baseline. If the intensity of OHV use is less 

under the baseline, it follows that adaptive management would be unnecessary to 

manage resources. These comments must be clarified or the adaptive management 

area should be removed from the plan and replaced with the baseline management 

strategies. (#8375)
14

BLM Response: While the No Action Alternative offers more area for use it does not 

provide any action that will give visitors an incentive to disperse. Additionally, the No 

Action Alternative does not address several other planning issues such as public health and 

safety issues and the conservation of T&E species.

#16 Public Concern: The BLM should develop detailed maps to support the 

Recreation Opportunity Spectrum.

Public Comment : Four maps are developed in the ROS framework: physical setting 

map, social setting map, managerial setting map, and ROS class map. We request the 

above mapping be done. As far as we know, no mapping has been done— none are 

provided in the DEIS or the DRAMP of this scale. The boundaries of the proposed 

management areas remain unclear and open to dispute. (#7226)

BLM Response: Management area maps have been prepared that utilize ROS categories. 

The boundaries of the management areas were designed by an interdisciplinary team of BLM 

professional resource specialists with years of experience in managing the ISDRA. Over 

time ISDRA recreationists have established an expectation of use and a cultural 

understanding as to the type of experience that one might have in different parts of the 

ISDRA. The interdisciplinary team utilized its understanding of this user defined “ROS 

areas” as a baseline to establish the management area boundaries. The existing boundaries 

were then adjusted to facilitate achievement of management goals. Specific ROS maps have 

not been developed but ROS categories are consistent with management area boundaries 

shown on the management area maps.

#17 Public Concern: The BLM should clarify the implications of using existing 

conditions as baseline prior to the interim closures.

Public Comment : The DEIS states that, the baseline condition is supposed to be 

before the interim closures, so how can the ROS classification provide for more 

intense use in an area where there were no prior ROS? The area was "wide open," 

you can't get more intense than that! (#8267)

Public Comment: The DEIS claims that Alternative 2 would not result in changes to 

existing land use patterns in the ISDRA: the BLM would continue to manage the 

ISDRA for multiple uses including recreation and resource protection. The baseline 

condition allows full-motorized use of the Adaptive Management Area. We refer you 

to page five of the DRAMP, Chapter I, Introduction which states: "Currently, as a 

result of a negotiated settlement agreement between the BLM and a coalition of 

environmental and off-road groups, several areas of the ISDRA are temporarily 

closed in order to protect various species. This Draft RAMP is written using the 

"current condition" as the management of the ISDRA prior to the temporary closure. 

Therefore, implementation of any alternative other than Alternative 1 would result in 

changes to existing land use patterns in terms of geographic distribution and 

concentration by displacement. Alternative 2, in adopting the Adaptive Management 

Area and the Buffer Zone, has a negative effect on recreational opportunities. We 

request that the EIS correct this oversight. (#8446)
15

BLM Response: The RAMP refers to the “baseline condition” as the condition of the 

ISDRA prior to the negotiated settlement. As a result some portions of the ISDRA were 

temporarily closed. The baseline refers to a starting point in which to start from. The use of 

an Adaptive Management Area in the center of the Dunes is a tool necessary to protect the 

sensitive habitat that the BLM is mandated by Congress to do. The Adaptive Management 

Area has a visitor supply of 75 groups (no more than 525 vehicles) per day during the 

visitation season. One permit would be valid for one group up to 7 vehicles for a period up 

to seven consecutive days. BLM realizes the OHV users like to travel in groups throughout 

the dunes area. Seven vehicles per group would accommodate most groups. BLM feels that 

525 vehicles per day is a good baseline for this management area. This number could go up 

or down in the future depending upon the ongoing monitoring. The ROS method has been 

used by Federal agencies for the past 20 years. It is a valuable tool in calculating the number 

of camping sites each ROS classification can sustain. The boundaries of the management 

areas were designed by an interdisciplinary team of BLM professional resource specialists 

with years of experience in managing the ISDRA. Over time ISDRA recreationists have 

established an expectation of use and a cultural understanding as to the type of experience 

that one might have in different parts of the ISDRA. The interdisciplinary team utilized its 

understanding of this user defined “ROS areas” as a baseline to establish the management 

area boundaries. The existing boundaries were then adjusted to facilitate management.

#18 Public Concern: The BLM should reconsider the cost and efficacy of the education 

program for the Adaptive Management Area.

Public Comment : I ask that you please reconsider the following parts of the draft 

proposal: The permitting process, including the requirement to pass a written test, is 

both unwieldy and impractical. Do you have figures as to the expense involved for 

additional staff to process the tests and track the permits? Has this written test 

procedure been proven effective on other BLM lands? (#191)

Public Comment: A resource conservation exam is unrealistic. It has the possibility 

of being discriminatory towards children and other people who may have mental, 

physical, or emotional difficulty taking exams. (#7282)

BLM Response: The Preferred Alternative of the FEIS proposes to eliminate testing and 

instead require completion of a brief education program to obtain a permit to enter the AMA. 

The management objective in the AMA is to provide for a world class quality semi-primitive 

motorized recreation opportunity. In achieving this world-class opportunity, the BLM has 

chosen a permit riding area. This will educate everyone using this area and provide 

recreational opportunities while allowing for conservation of habitat and plant species of 

concern. The BLM believes this management component represents a balanced approach to 

our multiple use mandate, and a reasonable decision-making tool to protect federally listed 

and sensitive species. Under the Endangered Species Act, the BLM is legally obligated to 

protect listed species. The RAMP has BLM estimates for the costs associated for the 

implementation of the Adaptive Management Area. The permit process has proven effective 

for the BLM, Forest Service, and National Park Service. If fraud becomes a problem, the 

BLM Rangers will take the necessary action in order to discourage that type of action. 
16

#19 Public Concern: The BLM should clarify how the ISDRA share of green sticker 

funds is determined.

Public Comment : I also am wondering why Glamis is having difficulty obtaining 

green sticker money. With all of the OHVs that come out to Glamis, I would think a 

large portion of the money would be used here. (#178)

BLM Response: The ISDRA receives approximately one million dollars for operations and 

maintenance through grants each year. BLM needs to compete for these funds on an annual 

basis and is not guaranteed any funding from the program. Competition for the funds is 

difficult due to the limited amount of OHV trust funds available to federal agencies. At one 

million dollars, the Dunes receive approximately a little less than 10% of the available funds 

for the State. At this time, the annual cost to manage the Dunes is approximately 4.5 million 

dollars.

#20 Public Concern: The BLM should manage the ISDRA within its current fee 

schedule and budget.

Public Comment : Some of your ideas may be good but it would cost too much to do 

them and the resources are limited and should be used on realistic things. Plus the 

public is not going to want to pay any more fees— we already have to pay Federal 

tax, State tax, green sticker fee, and dune user fee. You need to use your budget wisely 

and not keep asking for more money. Keep as is with the funding of law enforcement 

and things will be fine. (#5899)

BLM Response. The El Centro Field Office has received several millions of dollars in OHV 

Trust Fund grants over the last several years. These grants have funded operations and 

maintenance, 15 new toilets, paved access roads, law enforcement, emergency medical 

services, trash collection, toilet pumping and cleaning, and natural resource monitoring. In 

the future the grant and federal dollar allocations are expected to decrease as expenditures 

rise. With no other source of revenue, BLM will be revisiting the fee demo plan in FY03. 

The plan will be developed to make the fee program sustain the financial need of the entire 

dunes operations.

Due to the increased number of OHV enthusiasts and the decreased level of quality OHV 

recreation opportunities, visitation has substantially increased over the last several years. 

This, coupled with new types of non-motorized recreational visitors (party types with out 

OHVs), has caused a need for increased law enforcement. The BLM has responded to this 

need and has already started to change the recreational opportunities more toward a family 

atmosphere during the busy holiday weekends. The RAMP addresses the enforcement needs 

and provides additional tools for the responsible management of the Dunes. These actions 

will need funding from the fee demo program, grants, or federal appropriated dollars.

#21 Public Concern: The BLM should widen the study area for socioeconomic impact.

Public Comment : Pg. 3-8 Size of Socio-Economic Impacts Study Area. The DEIS 

admits that only 10% of ISDRA visitors are local, while the remaining 90% come 

from Los Angeles, San Diego, Phoenix, Tucson, and other areas of the U.S. This 
17

demonstrates that the study area for the "economic" impacts analysis should be 

widened. 3-48 Study Area for Socio-Economic Impacts Analysis. The study area for 

the DEIS's socioeconomic impact analysis is too small. At a minimum, it should 

include San Diego, Los Angeles, Orange, and Riverside counties. There is no basis 

for assuming that the vast majority of economic impacts occur in Imperial County 

and Yuma County. (#8286)

BLM Response: The socioeconomic section of the Final EIS has been rewritten. However, 

a new study on socioeconomic impacts was not done. 

#22 Public Concern: The BLM should manage the ISDRA in a way that recognizes the 

ISDRA's designation as a Natural Landmark.

Public Comment : We recommend that the BLM abandon this DEIS and its 

Proposed Management Plan, and start with something that recognizes the purpose of 

registering this site as a Natural Landmark, and something that shows the BLM 

really is capable of managing a destructive form of recreation in a way that protects, 

for everyone, the natural resources of the dunes. (#7312)

BLM Response: The ISDRA is registered as a Natural Landmark. The Federal Land Policy 

Act requires BLM to use and observe the principles of multiple use in developing land use 

plans for public lands. Multiple use is a concept that requires that public lands and their 

resource values be managed in a way that best meets the present and future needs of the 

people. Multiple use involves a combination of balanced and diverse resource uses that takes 

into account the long-term needs of future generations for renewable and nonrenewable 

resources. BLM will manage the ISDRA for resource conservation and meeting the current 

and future recreational use needs. Management will be consistent with the ISDRA 

designation as a Natural Landmark.

#23 Public Concern: The BLM should follow the National Historic Preservation Act 

by surveying and protecting eligible cultural sites within the ISDRA.

Public Comment : In addition to violating the NHPA and related statutes by not 

consulting with the Quechan and other tribes, the BLM is flagrantly violating the 

NHPA by carrying out an "undertaking" without making adequate assurances that 

NHPA eligible sites are protected. Prior to authorizing ORV use in the Dunes, BLM 

must carry out the requisite surveys. Allowing vehicles in the Dunes without doing 

such surveys violates both the NHPA and NEPA. (#8051)

BLM Response: BLM complied with cultural resource laws, initiating consultation with 

appropriate tribes and surveying a sample of the dune system. BLM initiated consultation 

with the Quechan and six other tribes and, in addition, BLM commissioned a Cultural 

Landscape Study of the Dunes that included interviews with elders and representatives of 

these tribes. An archaeological survey of 5% of the dune system was completed in 2002 for 

this plan. This was in addition to archaeological surveys conducted previously (refer to 

Table 3.8-1 of the Draft EIS). 
18

Endangered Species Act and Affected Environment

#24 Public Concern: The BLM should base decisions on scientific data rather tha n 

assumptions and opinions.

Public Comment : I do have great concerns with other aspects of the DEIS. The 

brunt of my concern centers on the difference between data and opinion. I have 

reviewed the plan very carefully and was alarmed to find inconsistent data in several 

areas. When consistent data was presented it was often unsupported. This leads me to 

the logical conclusion that an environmental study based on unsupported, 

inconsistent data must be deemed inherently flawed. As a California citizen and 

taxpayer I must stress that I, and I believe a great many others, would feel much 

better commenting on a study that was based on data properly analyzed by real 

scientists following the time tested scientific method; hypothesis, experimentation, 

data analysis and finally conclusion. (#7673)

BLM Response: It is the policy of the BLM to use the best available information for 

decision purposes. This may include both peer reviewed and non-peer reviewed data. 

Information gathered within the BLM and from other sources are utilized as appropriate. 

Inconsistencies and errors in the DEIS have been corrected in the FEIS.

#25 Public Concern: The BLM should reconsider the adequacy of the Thomas Olsen 

and Associates study and the 1998 -2000 monitoring study in the pla nning and decision -

making process.

Public Comment : The BLM can consider the TOA study and its 1998-2000 

monitoring studies in its planning and decision-making process. However, given the 

complex issues and controversy surrounding ISDA management, excluding the 

interim management regime based largely upon the BLM's suspect assessment 

process is arbitrary and capricious as a matter of law (5 U.S.C. [section] 706(2)(A)) 

and renders the BLM's range of alternatives quite unreasonable. This conclusion 

holds true even if we believed— which we do not— that the 1998-2000 monitoring 

studies and the TOA study were scientifically sound or provide the level of scientific 

proof necessary to make a reasoned and informed decision. Furthermore, the 

Biological Assessment's reliance on monitoring and impact assessment (ISDRA 

Biological Assessment 4-1 2002) is inadequate as it does not mitigate impacts or levy 

definitive protection for sensitive species. (#8052)

Public Comment: The BLM does not use "scientific integrity" or the "best scientific 

data" in the DEIS or Biological Assessment (BA). An example of this is the BLM's 

single-minded reliance on the Thomas Olsen Associates Inc. (TOA) 2001 study. 

Despite the obvious biases of this un-published, un-peer reviewed study— it was 

contracted by ORV groups— the BLM even uses the results of this study as 

justification to eliminate the Interim Management Alternative from the DEIS (BLM 

2002). In so doing, BLM ignores all the other studies at the Dunes that have found 

significant impacts from ORV use. (#8051)
19

BLM Response: BLM believes both studies are well designed and their results have been 

utilized in the FEIS. However, these studies were only two of many completed in past years 

that the BLM reviewed before issuing a Draft EIS. In addition, they were not a primary 

source of data in the decision making process. Literature used in the FEIS is based on 

individual merit and applicability and may include both peer reviewed and non-peer 

reviewed data. Information gathered within the BLM and from other sources are utilized as 

appropriate. 

#26 Public Concern: The BLM should use an independent team of scientists to support 

management decisions.

Public Comment : I urge the use of an independent team of scientists be used to 

support management decisions regarding protection. The Algodones Dunes are too 

precious a resource to allow further destruction. (#8225)

BLM Response: It is the policy of the BLM to use the best available information for 

decision purposes. This may include both peer reviewed and non-peer reviewed data. 

Information gathered within the BLM and from other sources are utilized as appropriate. In 

addition, the RAMP and EIS are carefully reviewed by local, state and federal agencies, 

including the U.S. Fish and Wildlife Service.

#27 Public Concern: In order to comply with NEPA, the BLM should establish 

ecological protection as the primary management goal for the ISDRA. BLM should 

manage the ISDRA for natural values.

Public Comment : The Purpose & Need of the RAMP Improperly Fixates on 

Providing for ORV Use: The purpose of the DRAMP/DEIS identified on page 6 of the 

Executive Summary places disproportionate emphasis on recreational ORV use to the 

detriment of the health and integrity of the ISDRA's broader landscape. . . . The 

Purpose and Need sections of the DRAMP/DEIS betray the BLM's intentions in the 

ISDRA: to prioritize ORV use, subordinating protection of the landscape is, at best, a 

second-tier priority. Fundamentally, the BLM must protect the broader ecological 

landscape within which those special status species rest, a principle that must be 

definitively and explicitly reflected within the Purpose and Need. NEPA imposes an 

affirmative obligation on the BLM to act as an ecological steward of our public 

lands. (#8052)

Public Comment: Overall, BLM'S proposed alternative is heavily weighted in favor 

of vehicular recreation and under weighted in protection of the environment. This is 

exactly the opposite of BLM's management mandate under the Federal Land Policy 

and Management Act (FLPMA) and the Endangered Species Act. BLM does have a 

multiple-use mandate under FLPMA, but scientific, scenic, historical, ecological, and 

environmental values must be protected (43 USC 1701 Sec. 102(a)(7)(8).) Protection 

of the environment should be the overriding goal of the plan, rather than recreation 

being given primary consideration, as it is in the DEIS and RAMP. For example, the 

RAMP at page 5 states that "The Draft RAMP emphasizes recreational use while 

providing for natural and cultural resource conservation and enhancement." That 

statement makes environmental protection secondary to recreational use, clearly a 
20

violation of FLPMA and the CDCA Plan. The heavy emphasis on off-highway vehicle 

(OHV) recreation also goes against BLM's multiple use mandate by being so heavily 

oriented toward a single use, OHV recreation. (#8052)

BLM Response: The Federal Land Policy Act requires BLM to use and observe the 

principles of multiple use in developing land use plans for public lands in compliance with 

NEPA. Multiple use is a concept that requires that public lands and their resource values are 

managed in a way that best meets the present and future needs of the people. Multiple use 

involves a combination of balanced and diverse resource uses that takes into account the long 

term needs of future generations for renewable and nonrenewable resources. BLM will 

manage the ISDRA for resource conservation, and meeting the current and future 

recreational use needs. 

#28 Public Concern: The BLM s hould maintain the current closures as control areas 

for scientific studies.

Public Comment : CNPS [California Native Plant Society] supports adaptive 

management of the dunes, and views the interim closures as necessary "control" 

areas by which to measure changes in the "experimental" or open areas— those areas 

open to motor vehicle use and other activities (the identified threat to the state and 

federally listed plant species). This concept is the very basic tenant of scientific 

experimental design, identified in every Biology 101 course. This experimental design 

assures that the native plant capital is conservatively managed until scientific 

evidence is produced on which to base adaptive management. By keeping the interim 

closures, both "control" and "experimental" areas are automatically set up 

throughout the dunes, which captures the geomorphic and climatological differences 

in habitat. (#184)

BLM Response: The Federal Land Policy Act requires BLM to use and observe the 

principles of multiple use in developing land use plans for public lands in compliance with 

NEPA. Multiple use is a concept that requires that public lands and their resource values are 

managed in a way that best meets the present and future needs of the people. Multiple use 

involves a combination of balanced and diverse resource uses that takes into account the long 

term needs of future generations for renewable and nonrenewable resources. BLM will 

manage the ISDRA for resource conservation, and meeting the current and future 

recreational use needs. Information gathered and analyzed after the settlement agreement in 

November 2000, suggests that maintaining the entire interim closures as control areas is not 

required for monitoring and study purposes. BLM feels the wilderness, where approximately 

25% of the habitat of special status species is protected, and the inclusion of the Adaptive 

Management Area where an additional 30% would be monitored and managed intensively 

will meet the conservation objectives for the Imperial Sand Dunes Recreation Area. 

#29 Public Concern: The Final EIS should include an analysis of each endemic species 

to the dunes.

Public Comment : The plan fails to analyze many dunes-endemic species. (#218)
21

BLM Response: The BLM, through the FEIS, has proposed monitoring efforts for a variety 

of plant and animal species that are intended to give managers the necessary information 

(data) to make decisions on the amount of OHV use that is appropriate based on population 

sampling of listed and sensitive species. Data on all species endemic to the ISDRA is not 

available for analysis. 

#30 Public Concern: To protect habitat types and landforms, the BLM should protect 

large areas in the central and southern dunes.

Public Comment : The North Algodones Dunes Wilderness is not enough (18%) to 

protect habitat types and landforms represented dunes-wide. To protect the over 80 

animal and 60 plant species found in the dunes, many of which only live there, BLM 

must protect large areas in the central, and southern dunes, south of I-8. (#1534)

BLM Response: In the preferred alternative in the EIS, the Adaptive Management Area 

(AMA) would be used to protect large areas in the central dunes. The AMA would limit 

OHV use and would be extensively monitored to ensure protection of identified species in 

the southern dunes area. In addition, seasonal closures will provide additional protection to 

sensitive species. The BLM, through the FEIS, has proposed monitoring efforts for a variety 

of plant and animal species that are intended to give managers the necessary information 

(data) to make decisions on the amount of OHV use allowed based on population sampling 

of listed and sensitive species. BLM believes this management component represents a 

balanced approach to its multiple use mandate and a reasonable decision making tool to 

protect federally listed and sensitive species. Under the Endangered Species Act, BLM is 

legally obligated to protect listed species. 

#31 Public Concern: The BLM should not save immigrant plant species at t he expense 

of public use of lands.

Public Comment : I do strongly disagree with preserving the dunes to the extent the 

conservationists wish. The understanding I have is the plant is not native to 

California. I do understand the desire to save a species from extinction. However, 

saving any species in an area it has immigrated to, in my opinion, is questionable. It 

is questionable especially when it comes at the plight of individuals in the right to use 

public land. We all own the land, and we may not agree with all of the uses, this is 

one case in which the "duners" have the right to maintain using the dunes. Again, the 

plant species is an immigrant, not native to the area and should not infringe on the 

rights of U.S. citizens from using their land. (#7591)

BLM Response: Peirson’s milk-vetch (Astragalus magdalenae var. peirsonii) is native to 

the Imperial Valley and the ISDRA. Under the Endangered Species Act, BLM is legally 

obligated to protect listed species. 
22

#32 Public Concern: The BLM should prot ect sensitive vegetation and wildlife by 

restricting OHV use.

Public Comment : We wish to strongly urge BLM to keep off-road vehicles out of 

Algodones. The closure protects sensitive plants and animals and opening it up will 

undoubtedly imperil many species. (#46)

Public Comment: The ISDRA is the only location where Peirson's milk-vetch is 

known to occur in the United States (see Exhibit 7). The ISDRA supports between 75 

and 80 percent of all of the world's known colonies of the species (Federal Register 

1998). The plant is scattered throughout the dune complex with a higher abundance 

along the central and western aspect of the Imperial Sand Dunes. Surveyors in 1977 

reported that no seedlings of any of the sensitive plant taxa, including Peirson's milkvetch, could be found in areas receiving heavy ORV use (Westec 1977). Moreover, 

large areas receiving intensive ORV use showed a virtually complete loss of all plant 

cover (Bury and Luckenbach 1983). By 1990, colonies of mature Peirson's milk-vetch 

could not be located in areas of heavy ORV use and colonies located in areas 

receiving moderate ORV use had lower reproductive success and poorer health than 

comparable populations located in areas closed to ORVs (ECOS 1990). (#8051)

BLM Response: Although desert ecosystems recover from human caused disturbances, the 

amount of time this recovery takes depends on a variety of factors. Rainfall, soil substrate, 

and parent material (other plants) all play a role. With continued disturbance, the desert 

often plays host to a variety of invasive (non-native plants), while wildlife species, often the 

transporters of parent material are displaced as well. Generally, the more continually 

disturbed an area is, the more time it will take to recover naturally, while in the meantime, 

some species of plants and animals may fail to repopulate a given area if their numbers are 

low elsewhere. The BLM, through the EIS, has proposed monitoring efforts for a variety of 

plant and animal species that are intended to give managers the necessary information (data) 

to make decisions on the amount of OHV use allowed based on population sampling of listed 

and sensitive species. 

#33 Public Concern: The BLM should justify access restrictions to protect sensitive 

species. The FEIS should include supporting data that supports claims that OHV use 

harms Peirson’s milk -vetch and that limiting OHV use protects it.

Public Comment : There is no scientific biological data showing restrictions on 

motorized recreation are necessary to protect any sensitive species. The proposed 

Adaptive Management Area is unnecessary as well as impractical from an 

administrative standpoint. The current "temporary" closures should be lifted and reestablished for OHV use. The recent scientific study/count by the American Sand 

Association documents more than 70,000 Peirson's milk-vetch plants in the currently 

"open" OHV areas. This plant is definitely not endangered. (#7808)

Public Comment: There is no evidence that OHVs cause a negative impact against 

the Peirson's milk-vetch in the dunes. It is not a victim of the OHV. In fact, we as 

responsible duners make a very conscious point to stay away from all natural plants 
23

and animals because we are environmentalists too. We are riding "in their house" 

and try to leave the plants and animals alone. Therefore, there is no justification to 

limit access to this area, as there is no scientific data or reason to limit our access to 

the Adaptive Management Area. (#7889)

Public Comment: I am not aware it has been proven that all-terrain vehicle or 

dune buggy use has harmed Peirson's milk-vetch in any way. I would hope the BLM 

would use acceptable science to determine whether there is any correlation 

whatsoever between off-road use in the closed areas of the ISDRA and the 

survivability of Peirson's milk-vetch. The growth of desert vegetation does not follow 

nice linear rules which appear to be applicable to non-desert vegetation. If there has 

been a decline in Peirson's milk-vetch in the closed areas of the ISDRA, I am 

wondering if it is possible for climatic and rainfall variables to have been factored 

out to make a certain determination that off-road vehicle use is harmful to Peirson's 

milk-vetch. How can a baseline which only goes back a few years accurately 

represent the range of climatic and rainfall variables which may affect Peirson's 

milk-vetch without a study period which takes into account the range of variables 

which may affect the survivability of Peirson's milk-vetch? (#164)

Public Comment : Pg. 3-25 and 3-26 Threats to Other Sensitive Plants. As with 

OHV impacts on the PMV, the DEIS grossly overstates the OHV threat to the 

Algodones Dunes sunflower, Wiggins Croton, Giant Spanish Needle, and sand food. 

BLM's monitoring reports (November 2000 and June 2001) do not support this claim. 

(#8286)

BLM Response: BLM issues management plans for a series of years, and therefore must 

take into consideration a potential increase in OHV activity, as well as the protection of 

natural resources associated with the ISDRA under federal regulations, as well as the 

Endangered Species Act. During the planning process, the BLM used the best available data 

in order to determine historical use of the ISDRA, as well as the impacts of OHV use. 

Although the area currently described as AMA (Adaptive Management Area) has likely 

received lower use than other areas, this may not always be the case. BLM feels that the 

AMA will accommodate recreation use and provide the flexibility to increase or decrease the 

number of permitted visitors in that area based on the intense monitoring program identified 

in the EIS. 

#34 Public Concern: The BLM should consider transplanting sensitive desert species 

to the dunes.

Public Comment : If the milk-vetch is so important, there are dozens of folks in 

Yuma that will be glad to grow it and the environmental do-gooders will be free to 

come and transplant all of them they wish! They can also trap and give some lizards 

to folks who raise reptiles and then offer $50 for each one. At that price, you can be 

sure the folks who raise such reptiles will be very successful at it. Then the millions 

the environmentalists have to spend on lawyers can be used to buy thousands of the 
24

lizards and they can place those in the wild when they transplant the milk-vetch 

plants we can raise by the thousands. (#1066)

BLM Response: Under the Endangered Species Act, BLM is legally obligated to protect 

listed species in their natural habitat. Although transplantation has been performed on a 

variety of animal species in the past, it has only been done with the intent of re-introducing 

those species back into their natural habitat, a requirement for recovery of a federally listed 

species. The Peirson’s milk-vetch is also part of a larger and unique plant community termed 

psammophytic (sand loving) scrub. Allowing the removal of this plant from the constituent 

community may have deleterious effects on other species as well. Since particular plants 

play a role in any given ecosystem, the effects of removing any one species, or allowing any 

one species to become removed, may give way to more listed species in the future.

#35 Public Concern: The BLM should not consider Peirson's milk -vetch as a factor in 

limiting use of the ISDRA.

Public Comment : I am convinced that Peirson's milk-vetch should be removed from 

the threatened species list, and should not be a factor in limiting the use of the 

Imperial Sand Dunes. (#169)

Public Comment: The milkweed issue as I feel it is merely an excuse for certain 

groups to close the area. (#6005)

BLM Response: The Peirson’s milk-vetch was listed under the Endangered Species Act by 

the U.S Fish and Wildlife Service. BLM is legally obligated to protect federally listed 

species in their natural habitat. 

#36 Public Concern: The BLM should not designat e any critical Peirson's milk -vetch 

habitat until its challenged threatened status is resolved.

Public Comment : Peirson's milk-vetch is doing fine. Its "Threatened" status has 

been challenged and any attempt to create a de facto "critical habitat" area should 

wait until this matter is resolved. This would not prevent the future critical habitat 

designation if the best available science proves the PMV needs it. (#8282)

BLM Response: The BLM does not “list” species. BLM does not designate critical habitat.

#37 Public Concern: The BLM should clarify how viability is defined for populations 

of native species.

Public Comment: In a related issue to maintaining habitat, BLM establishes a goal 

for biological resource management to "maintain viable populations of all native 

species throughout ISDRA." (Draft Biological Assessment, p. 2-9). Viable at what 

level? At the minimum possible level? Or at a higher level? What does BLM consider 

to be a measure of "viability" for a population? (#8009)

BLM Response: “Viable” describes a self-sustaining population and habitat that is capable 

of reproducing and regenerating without the need for human intervention. 
25

#38 Public Concern: The BLM should recognize that weather and natural forces 

impact the Adaptive Manageme nt Area and ISDRA more than OHV use.

Public Comment : As for the adaptive area, I have to say that I think you're way off 

track on the effects of usage by motorized vehicles. Nature is a hundred times more 

powerful of a force than the limited number of people that would visit this area, if 

opened up with no restrictions. It's well known that plant life goes in five to seven 

year cycles. I've seen this for years. It's directly influenced by wind blowing the dunes 

in certain directions, rain amounts from year to year, and temperatures in relation to 

that moisture. When the stars line up (so to speak) all these influencing factors result 

in a crop of plants. If you took the time to open up the area and monitor it for 10 

years you'd see that motorized vehicles don't impair the survivability of plants, as is 

the case for the last 40 years. These plants grow like weeds when the climate factors 

are just right. (#294)

Public Comment: As for species of concern in the dunes, all but one report confirms 

that OHV use in the ISDRA does not have a significant impact. And that one report 

was declared flawed by the BLM. One report states that the weather has more effect 

on Peirson's milk-vetch than to OHV use. These were studies initiated by the BLM. 

(#7873)

BLM Response: BLM does recognize that natural forces play a role in the natural 

environment. Rainfall, wind events, and drought all play a role in the ecology of the ISDRA. 

Although desert ecosystems recover from human caused disturbances, the amount of time 

this recovery takes depends on a variety of factors. Rainfall, soil substrate, and parent 

material (other plants) all play a role. With continued disturbance, the desert often plays host 

to a variety of invasive (non-native plants), while wildlife species, often the transporters of 

parent material, are displaced as well. Generally, the more continually disturbed an area is, 

the more time it will take to recover naturally, while in the meantime, some species of plants 

and animals may fail to repopulate a given area if their numbers are low elsewhere. BLM, 

through the EIS, has proposed monitoring efforts for a variety of plant and animal species 

that are intended to give managers the necessary information (data) to make decisions on the 

amount of OHV use allowed based on population sampling of listed and sensitive species. 

#39 Public Concern: The BLM should provide data demonstrating the need for 

motorized use restrictions in the Adaptive Management and Buffer Zone to protect 

sensitive species.

Public Comment : There is no justification for restricting motorized access using an 

Adaptive Management Area or Buffer Zone for biological and resource protection. 

(Sec. 2-7) The Draft Environmental Impact Statement (DEIS) assumes there is 

insufficient scientific data to support the temporary interim closures. Therefore, the 

1987 RAMP that does not include said closures, has been used as the baseline in the 

selection of the preferred Alternative. No data is provided to demonstrate restricting 

motorized access via an Adaptive Management Area (AMA) and a Buffer Zone (BZ) 

is necessary to protect any sensitive species. While there is no definitive visitor use 

data for the AMA, it is a well-known fact that this area is the lowest OHV use area at 

the ISDRA. Chapter 2-12, of the DEIS, Rationale for Rejection for 2.2.3 Interim 
26

Management Alternative states: The primary reason for rejecting this alternative is 

that interim closures (as stipulated in the settlement agreement was developed in 

November 2000 with plaintiffs (Center for Biological Diversity and others) to 

establish interim actions to protect endangered and threatened species pending 

completion of USFWS consultation on the CDCA Plan in total. Prior to November 2, 

2000, the BLM did not have the results of monitoring to assess adequately the status 

of sensitive species addressed by the settlement agreement. The results of the 

monitoring conducted since November 2000 and other data collected prior to 

November 2000 and assessed after the settlement agreement indicate that continuing 

the interim closures is not necessary to ensure adequate protection for the species of 

concern. (#8071)

BLM Response: The Adaptive Management Area (AMA) would be used to protect large 

areas in the central dunes. The AMA would limit OHV use and be extensively monitored to 

ensure protection of identified species in the southern dunes area. In addition, seasonal 

closures would provide additional protection to sensitive species. The BLM, through the 

FEIS, has proposed monitoring efforts for a variety of plant and animal species that are 

intended to give managers the necessary information (data) to make decisions on the amount 

of OHV use allowed based on population sampling of listed and sensitive species. BLM 

believes this management component represents a balanced approach to its multiple use 

mandate and a reasonable decision making tool to protect federally listed and sensitive 

species. Under the Endangered Species Act, BLM is legally obligated to protect listed 

species. This information has been added to Chapter 3 in the Proposed RAMP. 

#40 Public Concern: The BLM should not support the claim that OHV use negatively 

impacts desert wildlife.

Public Comment : On page 15 of chapter 4 the DEIS states "the Colorado Desert 

fringe-toed lizard and endemic dune beetles occurring in these dunes would be killed 

or injured by OHV activity." This seems very presumptive since, in all my years of 

visiting the dunes, I have never once seen a single dead lizard or beetle. Is there any 

evidence to support this claim? Most of the objective data collected seems to indicate 

that OHV use has only a very minor impact if any on desert biology in the dunes 

(table 4.2-2). (#8281)

Public Comment: The DEIS states that OHVs driving through desert wash areas 

may kill desert tortoises and destroy their burrows. The DEIS then claims that this 

same activity may have adverse effects on the Couch's spadefoot toad, which 

occasionally breed in the ephemeral ponds that develop in wash areas. However, the 

DEIS fails to provide any technical data in support of these contentions. We know of 

no data which indicate that OHV activity in the washes at ISDRA (or elsewhere) has 

damaged desert tortoises or Couch's spadefoot toads, or has otherwise jeopardized 

their reproductive success. The BLM, when finalizing the EIS, should remove such 

speculative comments from the document unless they can be substantiated with 

verifiable data. (#8286)

Public Comment: The DEIS claims that OHVs create negative impacts on certain 

special status wildlife species, including the Flat-tailed horned lizard and the Fringe-
27

toed lizard. However, there are no data demonstrating that OHV use in the ISDRA 

kills these species, crushes their burrows, or otherwise contributes to any real or 

perceived decline in their populations. (#8286)

BLM Response: All three species you mention may be adversely impacted by OHVs 

through direct mortality, injury, disturbance, habitat degradation and collection. To what 

extent such impacts will occur needs to be determined through the intense monitoring 

program identified in the EIS.

#41 Public Concern: The BLM should consider that OHV noise warns desert wildlife 

of approaching OHV traffic.

Public Comment : Chapter 4 page 15 argues that OHV noise levels would be 

detrimental to the desert animals causing a loss of hearing. I would argue that the 

loud nature of OHVs is better for the beetles and lizards because they have plenty of 

warning that a vehicle is approaching and can take cover well in advance of the 

passing of the vehicle, thereby avoiding any adverse impact or unintentional taking of 

animals. Also, since large groups of vehicles tend to travel on the dunes in single file, 

a beetle or lizard that hears an approaching vehicle and moves to avoid it will also 

avoid all of the other vehicles in the group that are following the leader. Perhaps this 

is part of why the majority of objective data shows that OHV activities are not 

impacting populations. (#8281)

BLM Response: Noise does warn them but they don't always get out of the way in time.

#42 Public Concern: The BLM should conduct surveys necessary to protect all species 

of concern.

Public Comment : The BLM suggests that studies "assessed after the settlement 

agreement, indicate that continuing the interim closures is not necessary to ensure 

adequate protection for the species of concern" (BLM 2002). This cursory conclusion 

is based entirely on the non-published, non-peer reviewed report of a non-expert 

biologist-for-hire paid for by the off-road vehicle industry (see Phillips et al. 2001). 

Even if the study could somehow be considered useful, scientific information 

supporting BLM's statement that the interim closures are "not necessary," the study 

deals only with plants. BLM has no information that any level of protection less than

that provided by the interim closures will protect any of the several dozen rare, 

threatened, endangered or endemic animals at the Dunes. The BLM never performed 

Desert tortoise surveys at the ISDRA; the last surveys for the Flat-tailed horned 

lizard were completed in the early 80's; and surveys for the Andrew's dune scarab 

beetle and Colorado Desert fringe-toed lizard required by the 1987 WMP were not 

conducted. (#8051)

BLM Response: BLM manages the ISDRA according to a multiple use mandate, as well as

the laws regarding federally listed and sensitive species populations. The BLM, through the 

EIS, has proposed monitoring efforts for a variety of plant and animal species that are 

intended to give managers the necessary information (data) to make decisions on the amount 
28

of OHV use allowed based on population sampling of listed and sensitive species. BLM 

believes this management component represents a balanced approach to our multiple use 

mandate. The flat-tailed horned lizard was surveyed at the Dunes in 1979, 1984, 1988, 1993, 

1994 and 1995. The major surveys were in 1979, 1988 and 1990. The fringe-toed was 

surveyed in 1987, 1988, 1989, 1991, 1993, 1996, 1997, 1998, 1999, 2001 and 2002. Tortoise 

surveys are scheduled for September 2002.

#43 Public Concern: The BLM should explain why it did not conduct transect studies 

of fringe-toed lizards every other year as mandated by the 1987 RAMP.

Public Comment : One objective of the HMP (1987) was to "determine the status of 

species of special management concern." BLM had a declared responsibility to 

monitor population trends in order to ascertain whether these species were being 

negatively affected by continued ORV use. For example, transect studies were to be 

conducted every other year to monitor trends in the dunes population of Colorado 

Desert fringe-toed lizards. One study was conducted in 1990; another study was 

possibly conducted in 1998; and BLM also conducted surveys in fall and spring 2001. 

Yet there is no evidence of additional survey data from between 1990 and 2001. 

Without these regular surveys, it is impossible to track long-term trends in the 

population and thereby "ensure that no special status species' continued existence is 

jeopardized." (#8051)

BLM Response: BLM surveyed for this species in 1987,88, 89, 91, 93, 96, 97, 98, 99, 2001 

and 2002.

#44 Public Concern: The BLM should justify closing 25,600 acres east of Glamis for 

desert tortoise habitat.

Public Comment : I do not agree with the closing of 25,600 acres east of Glamis for 

the desert tortoise habitat. This was done without any studies to identify this area as 

such. This area should be opened up immediately. (#7244)

Public Comment: Section 1.3.5 of the EIS indicates that 25,600 acres within the 

ISDRA (east of Glamis) was closed to camping because it is "desert tortoise habitat." 

Neither the BLM nor the U.S. Fish and Wildlife Service identify any of this area to be 

desert tortoise habitat. There is no mention of desert tortoise habitat in the lawsuit 

stipulation that initiated the closures to OHV use within the ISDRA. The closure of 

25,600 acres that was implemented on October 18, 2001 was done without any 

justification and should be reopened. Paragraph 1.3.7 (page 1-11) of the EIS, states 

that, according to the U.S. Fish & Wildlife Service, "the ISDRA is within the range of 

the desert tortoise but is not within critical habitat for any existing or proposed 

reserve area." (#7711)

BLM Response: 

This temporary closure is part of the negotiated settlement agreement between BLM and a

coalition of environmental groups. Approximately 1,200 acres has been proposed for 

inclusion within the ISDRA boundary. In the Preferred Alternative these 1,200 acres are 
29

proposed to be opened to camping. However, the areas closed to camping in 2001, and 

categorized as Desert Tortoise habitat, are identified as Desert Tortoise, category 3 habitat. 

Visitor Use 

#45 Public Concern: The BLM should permit OHV use at the ISDRA to protect the 

recreational investments of OHV enthusiasts.

Public Comment : I am sure that you know that there is thousands upon thousands of 

dollars invested by people in their off-road equipment, not to mention the thousands 

upon thousands that is spent on motor homes, campers, 5th wheels and trucks that get 

the families where they can enjoy their time away from home. Do you really think that 

the people just want to sit and look at their equipment sitting in their driveways. I 

don't think so. (#7792)

BLM Response: Under the Proposed RAMP and FEIS, all areas previously open to OHV 

use, before the temporary closures, will once again be open under an open or limited use 

designation. All areas will be reopened except the Adaptive Management Area, which will 

be accessible by permit only. Multiple designations allow the BLM to provide a quality 

motorized and non-motorized recreational experience, as well as meet our conservation goals

and requirements over the next 10 to 15 years. BLM is mandated to manage public lands to 

provide for multiple use and sustained yield. The California Desert (CDCA) Plan designated 

the ISDRA and several other areas for intensive OHV use. The 1987 RAMP provides 

guidance for management of the dunes based on the amount of use and current information 

regarding natural and cultural resources. This plan update was necessary because of changes 

in the numbers and types of use and additional information regarding natural and cultural 

resources. The Proposed RAMP will ensure that OHV recreation opportunities are allowed 

to continue while conserving natural and cultural resources. 

#46 Public Concern: The BLM should prohibit OHV use in the ISDRA.

Public Comment : As a concerned citizen I would like to voice my opposition to the 

further degradation of the Imperial Sand Dunes region by the vocal but relatively 

small group of recreational vehicle enthusiasts. As more and more of our public lands 

are being compromised by the pressure of over-population it is important that 

agencies such as the BLM recognize that there is an overwhelmingly large proportion 

of citizenry of this state, and indeed the nation, who want to safe-guard our remaining 

open spaces. I call on the BLM to prohibit the use of these vehicles throughout the 

dunes system. (#7526)

BLM Response: The Federal Land Policy Act requires BLM to use and observe the 

principles of multiple use in developing land use plans for public lands. Multiple use is a 

concept that requires that public lands and their resource values are managed in a way that 

best meets the present and future needs of the people. Multiple use involves a combination 

of balanced and diverse resource uses that takes into account the long term needs of future 

generations for renewable and nonrenewable resources. BLM will manage the ISDRA for 
30

wilderness, conservation of species and habitats, OHV recreation and a variety of recreation 

programs. 

#47 Public Concern: The BLM should consider protecting the South Algodones Dunes 

with applicable laws and programs.

Public Comment : The omission of the 61,630 acre South Algodones Dunes from the 

1994 Wilderness Bill (DRAMP, p. 9) does not preclude that area from protection 

under the Endangered Species Act, or under the State of California's Wildlife Habitat 

Protection Program, required as a condition of receiving State OHV grants, on which 

BLM depends for management of the ISDRA. If BLM proposes to use historic events 

for management today, it should revert to the 1968 designation of the entire dunes 

system as a "Special Natural Area" and remove all off-road vehicle use. (#7312)

BLM Response: This area was studied for potential as a wilderness area and released as 

unsuitable by Congress in 1994. Under the preferred alternative in the FEIS it would be 

conserved through implementation of the Adaptive Management Area program. Limited 

OHV use, extensive monitoring of sensitive plants and animals, and seasonal closures 

proposed in the Preferred Alternative would help protect this area.

#48 Public Concern: The BLM should justify its assertion that OHV mobility allows 

more restrictive limits on OHV ac cess near the inner dunes without impacting viewing 

opportunities.

Public Comment : Page 4-71 4.6 Visual Resources 4.6.2.2 Change in ROS 

Designation. I believe that allowing more intense use in a particular management 

area provides views of the inner dunes to more recreationists at one time, and is a 

visual benefit. It is also clear that allowing less intense use in a particular 

management area provides views of the inner dunes to fewer recreationists at one 

time. There is no logical connection to the assumption that a "high level of mobility'' 

can offset a lower level of allowable use that would not adversely affect view 

opportunities of the OHV enthusiasts. (#7952)

BLM Response: The Imperial Sand Dunes has a superb variety of scenic value resources 

and are considered an important component to the recreation experience. The contrast rating 

process is a tool used to determine the extent of visual impact that proposed resource 

management activities would create in a landscape. It serves as a guide for reducing visual 

impact to acceptable levels and defined by the visual management objectives and multiple 

use class guidelines.

#49 Public Concern: The BLM should promote non -motorized recreation 

opportunities at the ISDRA.

Public Comment : The preferred alternative gives special preference to recreation 

intended for OHV use almost exclusively. I would like to see the dunes made more 

available to people who would like to experience the dunes on foot. This could 

include a short tour available for travelers coming through by bus or car who could 

take a short tour, perhaps on a board walk with kiosks telling about this unique 
31

habitat. Longer hikes should also be made more accessible. At this point it is very 

difficult to park and hike into the dunes for more extensive hikes. An even broader 

look could be made at encouraging eco-tourism which would include other 

neighboring desert resources, including the Palo Verde Woodlands, Anza-Borrego 

State Park, the Salton Sea and Colorado River. Making access for foot traffic might 

mean doing some reconfiguration of the areas closed to vehicles. (#279)

BLM Response: The watchable wildlife site on the eastern side of the North Algodones 

Dunes Wilderness provides for a two-wheel drive access point for short and long hikes into 

the Dunes. When staffing and funding allow, the BLM provides free-guided interpretive 

hiking tours to enhance the public’s knowledge and appreciation of natural and cultural 

resource conservation. In addition to this, the Proposed RAMP proposes to create a new bus 

parking area and interpretive site on Greys Well Road. This site would have interpretive 

kiosks with conservation-oriented information and an area closed to motorized use for 

interpretive hikes. In order to meet the BLM’s multiple use mandate, public lands in the 

ISDRA are managed as open, limited, closed, and designated under a range of classes from 

the recreation opportunity spectrum. These multiple designations allow the BLM to provide 

a quality motorized and non-motorized recreational experience, as well as meet our 

conservation goals and requirements. The North Algodones Dunes Wilderness provides for 

over 26,202 acres for non-mechanized recreation opportunities. The Adaptive Management 

Area would permit a limited number of OHVs in order to allow a semi-primitive motorized 

recreational experience while conserving the natural and cultural resources. 

#50 Public Concern: The BLM should not favor OHV use at the ISDRA in response to 

receiving OHV-generated funds.

Public Comment : The claim is often made that off-roaders pay their way through 

green-sticker funds, Symms Act funds, etc. This is not at all the case. . . . In any case, 

ISDRA is still public land, and is not owned by the off-roaders, even though they have 

been, and, under present plans, will be granted, de facto, exclusive use of most of it. 

Off-highway vehicle recreation does not belong on public land. The government 

should not be running amusement parks for off-roaders. (#202)

BLM Response: The ISDRA is mainly funded through California State Parks, Off-highway 

Vehicle Trust Fund grants, congressionally appropriated funds, and by revenues generated on 

site from visitor use fees. At this time the majority of the funding for the dunes is from 

congressionally appropriated dollars. After the record of decision is signed for the RAMP, 

BLM will move forward in the preparation of a new fee demo plan for the Dunes. The new 

fee demo plan will address the future planned funding shortfalls from federal and grants 

dollars. Off-highway vehicles are an appropriate use of public lands, as stated in the Federal 

Land Policy Act, 1976. As such, BLM continues to strive to meet its multiple use mandate. 

Multiple designations allow the BLM to provide a quality motorized and non-motorized

recreational experience, as well as meet our conservation goals. The North Algodones Dunes 

Wilderness provides for over 26,202 acres for non-mechanized recreation opportunities and 

is the only area in the Dunes designated exclusively for a particular type of recreation (nonmechanized).
32

#51 Public Concern: The BLM should separate OHV and pedestrian use areas.

Public Comment : Trying to combine hiking with off-road vehicle use is foolish. 

Motor vehicles cannot safely share space with pedestrians and the laws against cars 

on sidewalks and pedestrians jaywalking are a necessary feature of daily life as 

society attempts to keep walkers and vehicles separated in space to preserve lives. 

The regulations on use of the dunes should be crafted to forbid pedestrians in the 

small area reserved for vehicles and to forbid vehicles in the larger area reserved for 

wildlife and pedestrians. Unless this is done, the BLM plan for the dunes is a 

blueprint for carnage. (#7581)

BLM Response: Multiple land use designations allow BLM to provide a quality motorized 

and non-motorized recreational experience, as well as meet our conservation goals and 

requirements. The North Algodones Dunes Wilderness provides for over 26,202 acres for 

non-mechanized recreation opportunities. The preferred alternative in the FEIS also 

identifies and area in Buttercup allowing interpretive kiosks and trail for non-motorized 

recreation. The Adaptive Management Area would have a limited number of OHVs in order 

to allow a semi-primitive motorized recreational experience while conserving the natural and 

cultural resources. 

#52 Public Concern: The Final EIS should address mitigation for regional OHV 

dispersal caused by any OHV limitations at the ISDRA.

Public Comment : Implementation of any Alternative that further restricts OHV 

activity and decreases the available amount of area for OHV operations would 

require some type of mitigation. Further restrictions on OHV activity would cause 

OHV enthusiasts traveling to other sites, thus resulting impacts become an issue in 

those other areas that need to be addressed. (#7226)

BLM Response: Regional dispersal of OHV activity as a result of visitor capacity limits at 

the ISDRA is not anticipated. Present and projected visitation will be able to be 

accommodated utilizing the management strategies identified in the Proposed RAMP and 

FEIS. The BLM is mandated to manage public lands to provide for multiple use and 

sustained yield. 

#53 Public Concern: The BLM should reduce collision danger by opening more areas 

to OHVs.

Public Comment : Glamis can and should be shared by off-road vehicles. There are 

plenty of out-of-bounds areas in ISDRA for other uses and increasing the size of 

available areas will reduce congestion and accidents. I do not think it will greatly 

increase the number of current users. It will just make it more safe and fun for 

existing users. . . . If the closure areas remain, it will create a dangerous two lane 

condition around the perimeter of the closed areas or the AMA (Adaptive 

Management Area). I have seen and experienced near miss head-on collisions and 

have heard of many fellow off-roaders saying the same. (#292)
33

BLM Response: The temporary closures agreed to in November 2000, received 

concurrence with the understanding that the RAMP and EIS would address the Special Status 

Species issues. At the signing of the Record of Decision of this EIS, the closures will be 

lifted and the Proposed RAMP and Final EIS will take effect. However, the Dunes are a 

limited resource, and the BLM is mandated to manage public lands to provide for multiple 

use and sustained yield. Substantially increasing the size of the recreation area is beyond the 

scope of the FEIS. The California Desert Conservation Area (CDCA) Plan designated the 

ISDRA and several other areas for intensive OHV use. The 1987 RAMP provided guidance 

for management of the dunes based on the amount of use and current information regarding 

natural and cultural resources. This plan update was necessary because of changes in the 

numbers and types of use and additional information regarding natural and cultural resources. 

The BLM and State of California have several rules and regulations in order to promote safer 

riding. These include the need for a whip flag, the prima fascia speed law, the helmet law, 

and required lighting. Even though these laws are in effect and enforced in the Dunes, OHV 

recreation is an inherently dangerous activity and requires the application of honed driving 

skills and common sense.

#54 Public Concern: The B LM should minimize restrictions at the ISDRA to preserve 

a sense of freedom.

Public Comment : As to the other proposed rules for use of the Imperial Sand 

Dunes, there are already way too many laws and rules to obey in this world. People 

need a place where they can be left alone and at least feel for a brief weekend the 

illusion of freedom from rules. Please, no more rules, and reopen the dunes. (#192)

BLM Response: Between 1980 and 2001 there has been an increase of 108% of registered 

OHV’s in California. Between 1994 and 2001 there has been an increase of 74% of street 

licensed 4 wheel drive vehicles, and between 1980 and 2000 there has been a 48% decrease 

in the amount of acres available for OHV recreation (Taking the High Road, CA State Parks, 

2002). Due to the increased number of OHV enthusiasts in California, and the decreased 

level of quality OHV recreation opportunities, visitation in the ISDRA has increased. This, 

coupled with new types of non-motorized recreational visitors (party types without OHVs), 

has caused a need for increased law enforcement. BLM has responded to this need and has 

already started to change the recreational experience toward a family atmosphere during the 

busy holiday weekends. The RAMP addresses the enforcement needs and provides 

additional tools for the responsible management of the Dunes. These tools (proposed rules) 

have been developed and are proposed to be adaptive so they may be used when needed and 

removed at a later date in order to ensure a quality recreational experience.

#55 Public Concern: The revised RAMP should not limit visitor numbers.

Public Comment : The capacity limits are far too restrictive and do not allow for 

annual growth. Any limitations on the number of people visiting the dunes have a 

definite negative impact on the economy of local businesses in Yuma and the Imperial 

Valley. Why not allow the dunes to be accessed as they were prior to November 2000, 

then study the use patterns and later determine if any capacity limitations are truly 

necessary? (#191)
34

Public Comment: Arbitrary capacity limits on the various dune areas does not 

appear to be necessary, or justified at this time. If, after an adequate study period and 

current efforts to reduce lawlessness and other enforcement issues are not thought to 

be successful, then maybe rational capacity limits need to be considered for the major 

holidays that draw large crowds. Again, capacity would be reduced, by restricting 

entrance to campers and duners only. (#894)

BLM Response: BLM has revised the visitor capacity limits in the FEIS. The capacities 

identified in the plan are based on the amount of visitors the various management areas can 

sustain and continue to meet Recreation Opportunity Spectrum (ROS) objectives. This is 

designed to protect the experience during the bulk of the year. There is a recognition that 

these limits will be exceeded, and the desired condition degraded, during peak use periods. 

Given the current use levels during the off-season there is little chance that capacity limits 

will be reached in the near future. Many state, federal, and private organizations use capacity 

limits as a management tool, including the BLM, National Forest Service, National Park 

Service, and numerous state parks. Multiple land use designations allow the BLM to provide 

a quality motorized and non-motorized recreational experience, as well as meet our 

conservation goals and requirements. Under the Endangered Species Act, the BLM is legally 

obligated to protect listed species. BLM, through the FEIS, has proposed monitoring efforts 

for a variety of plant and animal species that are intended to give managers the necessary 

information (data) to make decisions on the amount of OHV use allowed based on population 

sampling of listed and sensitive species. BLM believes this management component 

represents a balanced approach to our multiple use mandate, and a reasonable decisionmaking tool to protect federally listed and sensitive species. 

#56 Public Concern: The BLM should adjust visitor use estimate s by the type and 

length of visit.

Public Comment : I believe tour bus stops or anything that would generally be 

regarded as a casual instance should not be counted towards visitor supply. . . . As a 

possible solution, the BLM should consider the possibility of requiring the purchase 

of a day use permit that would not be counted towards visitor supply. (#8010)

Public Comment: A visit may just be a short visit (20 minutes) or a week long 

camping trip. If there are going to be visitor limits then a distinction should be made 

as to how long a person will be staying in the dunes. It wouldn't be fair to count a bus 

carrying 40 people the same as ten families camping for a week. (#7298)

BLM Response: The capacity limits set in the RAMP will allow for the current number of 

visitors to continue to recreate at the ISDRA. Should use increase to the point that the 15% 

or 20% triggers are activated, the actions taken will be focused on better educating and 

dispersing use to non-peak periods. Trigger resets have been established and the visitor 

capacity has been raised in the FEIS to include additional camping areas not previously 

addressed. Each year at the end of the season there will be an end of the year review of the 

visitation data. If it is found that visitation has exceeded the capacity for over 20% of the use 

season or if it is found that the capacity has been exceeded by over 15% for two years in a 

row, a determination will be made to enforce the capacity daily limit during the following use 
35

season. BLM will use the off-season period (June-September) to notify the public that the 

capacity will be enforced. Visitors will have the option of reserving 50% of available 

campsites in advance. The remainder will be available on a first come first serve basis. 

BLM recognizes that there are several assumptions that were necessary to develop the 

capacity estimates contained in the Proposed RAMP and FEIS. During FY2003, the BLM 

will conduct a visitor use study to verify these assumptions. This will give the BLM the 

ability to more accurately count the number of visitors at the ISDRA. Inconsistent data in the 

DEIS has been corrected in the FEIS and Proposed RAMP.

#57 Public Concern: The revised RAMP should not include holidays in Recreation 

Opportunity Spectrum calculations.

Public Comment : The six major holiday weekends and their shoulder days represent 

less that 6% of a year. Therefore, they can be considered rare exceptions rather than 

the norm. Until it is scientifically proven that these days impose a major negative 

impact beyond LAC on the ISDRA natural and cultural resources, these days should 

be excluded in carrying capacity estimates for trigger application. (#7226)

BLM Response: The capacities identified in the plan are based on the amount of visitors the 

various management areas can sustain and continue to meet ROS objectives. This is 

designed to protect the experience during the bulk of the year. There is a recognition that 

these limits will be exceeded, and the desired condition degraded, during peak use periods. 

Given the current use levels during the off-season there is little chance that capacity limits 

will be reached in the near future.

#58 Public Concern: The revised RAMP should increase available camping spaces 

rather than limiting visit or numbers.

Public Comment : There are a few areas I find puzzling. I'd like to start with the 

capacity limits (chapter 4, page 6), what type of information was used to arrive at the 

numbers suggested? I suggest increasing the amount of spaces available to camp in, 

instead of trying to limit the amount of campers. (Individual, No Address - #2561)

Public Comment: As stated by Dr. Haas that day [at the public meeting], the core 

intent of ROS triggers is to determine and signal the need for more visitor supply but 

not act as a deterrent as presently formatted in the DEIS. . . . Haas was emphatic 

stating several times, "Capacity does not mean closing the doors." This capacity 

needs to be increased when a trigger has been reached. . . . This is the true intent of 

triggers and capacity. It is obvious that CH2MHILL erred grievously in its 

interpretation of what capacities and triggers are and how they should be applied. 

We strongly encourage that the aforementioned information provided by Dr. Haas at 

the Workshop and in his February 15, 2002, draft be reconsidered for inclusion in the 

Final EIS and RAMP. (#7953)

BLM Response: Refer to Chapter 3 of the FEIS for a description of ROS and the capacity 

numbers for the different management areas. BLM intends to increase the available camping 

spaces in designated management areas. Multiple designations allow the BLM to provide a 

quality motorized and non-motorized recreational experience, as well as meet our 
36

conservation goals and requirements. The 20 percent trigger identified in the Proposed 

RAMP requires a study to investigate the appropriateness of increasing available camping 

spaces. 

#59 Public Concern: The Final EIS should acknowledge that increased OHV use in 

some areas of the ISDRA is a direct result of OHV closures of other areas at the 

ISDRA.

Public Comment : The plan uses mitigation and impact scenarios based on an 

established "baselines" and what is "measured" at present. In reading these, I noted 

that most figures were taken in 1999 and compared with what has happened in 2001 

(or 2002 if data was available). In using these figures, the BLM and their partners in 

writing this plan failed to present to the reader the fact that an increase in usage in 

certain areas is a direct result of the closure of approximately 50% of the previously 

available riding areas. Specifically, this has resulted in the closure to camping along 

Ted Kipf Road. The closure notice states, in writing, "the unusual increase" in usage 

of these areas. It takes very little stretch of the imagination to realize that if the 

amount of users grow proportionately to the average population growth, then usage 

rates will grow disproportionately if the available use areas are cut significantly. 

(#7243)

BLM Response: BLM acknowledges that increased OHV use in some areas is a direct 

result of OHV closures in other areas of the ISDRA. . Multiple land use designations allow 

the BLM to provide a quality motorized and non-motorized recreational experience, as well 

as meet our conservation goals and requirements. Under the Endangered Species Act, the 

BLM is legally obligated to protect listed species. BLM, through the FEIS, has proposed 

monitoring efforts for a variety of plant and animal species that are intended to give 

managers the necessary information (data) to make decisions on the amount of OHV use 

allowed based on population sampling of listed and sensitive species. BLM believes this 

management component represents a balanced approach to our multiple use mandates, and a 

reasonable decision-making tool to protect federally listed and sensitive species

#60 Public Concern: The BLM should base management on counts of visitors rather 

than estimates.

Public Comment : The BLM should do its visitor count via aerial photos or 

observation or by on-the-ground, manual counting. The axle counter system currently 

being used is vastly inaccurate for reasons listed in the OHV group and ASA 

comments. The BLM must do more in depth studies to better determine an accurate 

capacity taking into consideration actual patterns including but not limited to areas 

between camping pads. (#7948)

BLM Response: Prior to the 2001 dune season, collection of visitation numbers was done by 

car counters and hand counts. Spring of 2001, the BLM updated the visitation counters by 

placing 8 counters on all the hard surfaced entry areas in the ISDRA. The visitation numbers 

reflected in the DEIS are weekly counts for visitation in one week periods. The BLM uses 

the national standard average of 3.5 people per vehicle for the formula in determining the 

amount of visitation in the ISDRA. The BLM recognizes that there are several assumptions 
37

that were necessary to develop the capacity estimates contained in the Draft RAMP and 

DEIS. During FY2003, the BLM conducted a visitor use study to verify these assumptions. 

Instead of the 3.5, which is used nationally for the number of visitors per vehicle, those areas 

that were surveyed the number appeared to be 2.3 dunes-wide, however not areas of the 

dunes were surveyed. If BLM were to use the 2.3 or the number that best reflects the number 

of visitors per vehicle at the dunes, rather than the national number of 3.5 the visitor supply 

number would be reduced dramatically. This would not have a bottom line change in 

management since all calculations were based on the number of vehicles per acre.

#61 Public Concern: The Final EIS should justify OHV use limitations in the Adaptive 

Management Area.

Public Comment : No justification is given to limit access to the [Adaptive 

Management Area]. (#8253)

Public Comment: The provision for only 525 vehicles per week seems odd. Where 

did this number come from? How do you know that this is a sufficient number? How 

do you know that this system will work? If this was to be instituted shouldn't a pilot 

program that allows for comments be instituted before it is written into the plan? 

What if it is found that the current usage rate does not impact the area as suggested, 

if written into the plan, it cannot be reversed. (#7951)

BLM Response: The BLM is mandated to manage public lands to provide for multiple use 

and sustained yield. To allow use to continue within the Adaptive Management Area, BLM 

must be able to ensure that there will not be a degradation of all sensitive, threatened, and 

endangered plant and animal species and their habitats. To do this, BLM has designed the 

adaptive management approach described in the RAMP. Through monitoring of use and 

natural resources BLM will be able to identify changes to the adaptive management program 

that will provide for the optimum amount of use for all user groups while ensuring 

sustainable populations of these species. The 525-vehicle limit is BLM’s estimated number 

of vehicles that can be allowed while still meeting its goals in the Adaptive Management 

Area and is based on historical use in the AMA. With new data there would be a 

reassessment of the challenges and an adjustment of management objectives and planned 

actions to the adaptive management area. 

#62 Public Concern: The BLM should not limit use i n the Adaptive Management Area 

or other areas unless or until monitoring demonstrates a need for use limits.

Public Comment : We suggest that a permit system be initiated only in the unlikely 

event that monitoring results are deemed to warrant such a program based on 

resource conditions. Since no destinations lie within the suggested boundary, it is our 

belief that aerial photographs or spotters in the Central Dunes Management Area, 

even on holiday weekends, will reveal little if any usage within the suggested 

boundaries. Therefore, a permit system would not be required. (#7226)

BLM Response: Adaptive management is a mechanism for integrating scientific knowledge 

and experience for the purpose of understanding and managing natural systems such as the 

ISDRA ecosystem. BLM will manage the Adaptive Management Area in a manner that 
38

provides recreational opportunities while allowing for the conservation of habitat and plants 

and species of concern. The initial limit of 525 vehicles in the Adaptive Management Area 

was derived using ROS coefficients. BLM believes this management component represents 

a balanced approach to its multiple use mandate and a reasonable decision-making tool to 

protect federally listed and sensitive species. Under the Endangered Species Act, the BLM is 

legally obligated to protect listed species. BLM monitored the interim large closure in 2001 

and 2002 and had sufficient staff to accomplish its conservation goal. Weekly over flights of 

the area and OHV patrols on the weekends were used to assist the enforcing/monitoring of 

the area. BLM management actions will monitor the AMA and revise the permit program if 

necessary. 

Vendors

#63 Public Concern: The BLM should expand vendor opportunities at the Glamis 

Management Area.

Public Comment: I would personally like to suggest that the BLM expand vendor 

opportunities so that spare parts and repairs are more available in the Glamis area. 

While I understand this presents unique challenges to meet BLM regulations and 

equitable "taxation" for goods and services rendered, it is far less of a challenge than 

providing and funding additional law enforcement activities and the additional 

monies collected could be used to help fund these very activities. (#7829)

BLM Response: BLM recognizes the service and convenience that the vendors and private 

business in the local area provide to the ISDRA visitors. The Preferred Alternative in the 

FEIS would allow limited short term weekend vending to continue in the ISDRA, with 

holiday exceptions, as well as allow long term vending on the vendor pad at Gecko Road. 

The fee to vend in the dunes would be addressed in the new fee demo business plan.

#64 Public Concern: The BLM should not allow mobile vendors at the ISDRA.

Public Comment : The mobile vendors should not be allowed because they are a 

safety hazard. I have had them pull out in front of me on Gecko Rd. when I was 10-20 

ft. from them. They block traffic and then keep it blocked, even if emergency vehicles 

need to pass. I have seen kids almost get run over trying to get to the ice-cream 

trucks. (#8241)

BLM Response: The Preferred Alternative in the FEIS does not change the policy that has 

been proposed for mobile vending and it would be allowed to continue in the ISDRA. 

Existing regulations require mobile vendors to park at least 10 feet off the road and not 

obstruct traffic.

#65 Public Concern: The Final EIS should specify what vendor services will be 

permitted at the ISDRA.

Public Comment : Chapter 1-13, paragraph 4, the statement, "A revised RAMP will 

limit vendors and concessionaires in the ISDRA to those that provide food, goods, or 
39

services that support OHV use and camping" is too vague. Who will decide what is 

appropriate? Please be more specific. (#8364)

BLM Response: The preferred alternative in the FEIS would allow products and services to 

be sold with that provide food, goods, or services that support OHV use and camping. 

However, the BLM has a list of items prohibited from commercial sale in the ISDRA that do 

not contribute to a safe or legal visit.

#66 Public Concern: The BLM should address the impact of vendors to the local 

economy.

Public Comment : Their [vendors] local economic impact (taxes, permits, supplies 

purchased and resold at the dunes) should be considered before implementing any 

decisions on their stays. (#8255)

BLM Response: The BLM recognizes the service and convenience that the vendors and 

private business in the local area provide to the ISDRA visitors. The preferred alternative in 

the FEIS would allow limited short term weekend vending to continue in the ISDRA, with 

holiday exceptions, as well as allow long term vending on the vendor pad at Gecko Road. 

The fee to vend in the dunes would be addressed in the new fee demo business plan. The 

socioeconomic effects of the preferred alternative are addressed in the FEIS.

Law Enforcement

#67 Public Concern: The BLM should justify the assertion that North Algodones 

Wilderness trespass is a problem.

Public Comment : Page 15 Par. 4 refers to ". . . the problem of trespass in the NA 

Wilderness." Any accusation statement should be quantified. Again, the reader is led 

to believe that trespass is widespread and blatant. If this is to be an unbiased 

management plan, this type of verbiage should be left out. In addition, the BLM 

response to question #10 on page 35 in fact states that ". . . total frequency of 

trespass is not known." Assumption of a problem is not good management. (#8508)

BLM Response: In general, trespasses in the North Algodones Wilderness Area are 

relatively infrequent and impacts from such activities have had a minor impact. The FEIS 

more accurately reflects this situation.

#68 Public Concern: The BLM should establish a 15 mile per hour speed limit in the 

proximity of camping pads along Gecko Road .

Public Comment : Lower the speed limit to 15 MPH in the proximity of all existing 

camping pads. As more pads are constructed, lower the speed limit in those sections 

of the road as well. Ultimately, the whole of Gecko Road would have a 15 MPH speed 

limit. . . . With the decrease in speed along the road, public safety would be further 

enhanced. (#7226)
40

BLM Response: There is currently a rule in effect that limits speed to 15 mph within 50 feet 

of any group of people or campsite. BLM is planning to train several rangers in the use of 

radar guns to assist in enforcing these rules.

#69 Public Concern: The Final EIS should include a clear law enforcement plan and 

methodology.

Public Comment : Management of the Algodones Dunes has become so dangerous 

that a recent Department of Interior (DOI) "Law Enforcement Special Evaluation" 

concluded that the dunes are "unsafe for family recreation activity due to the use of 

drugs and alcohol, and the problems of lawlessness that occur with such use." The 

DOI recommends that BLM rangers be issued riot helmets, batons, and gas masks for 

their own safety. On average there are about 29 law enforcement staff present during 

each holiday weekend. Under the action alternatives (2, 3, 4), the BLM proposes to 

increase permanent law enforcement for the six major holiday weekends (BLM 2002). 

Recently, the El Centro Office increased their staff from five permanent positions to 

eight, and it expects to fill four more positions by the end of the year to fulfill the new 

RAMP. However, the DEIS does not provide a clear law enforcement plan and does 

not offer evidence of a methodology. (#8051)

BLM Response: BLM has a detailed plan in place to deal with the current and anticipated 

future conditions. For officer safety and tactical reasons this information cannot be given to 

the public and cannot be included in the EIS.

#70 Public Concern: The BLM should use adaptive management principles to 

implement curfews and alcoholic beverage bans.

Public Comment : I recommend that if curfews and an alcohol ban become part of 

the RAMP, the elements of adaptive management be used in their implementation. 

(#8300)

BLM Response: The Proposed RAMP would continue to emphasize a co-operative 

approach to law enforcement. Local, State and Federal law enforcement officers, working 

together, would provide increased law enforcement. In addition, several management 

techniques would be implemented to increase law and order. These techniques include 

establishing two new tools. These tools are curfews and restrictions in areas of historic 

lawlessness and limiting alcohol use to established camp areas. Visitor use and incident data 

are currently monitored and will be used to evaluate the specific need for these tools and to 

develop the criteria for their use. These tools would be used as needed, but are not expected 

to be continuously required. Application of current laws, such as speed limits and reckless 

driving, will be used initially to address safety issues. Curfews and restrictions will be used 

as an additional tool when existing laws and actions are not producing a safe environment. It 

is anticipated that these actions would restore a safe family atmosphere at the Imperial Sand 

Dunes Recreation Area. 
41

#71 Public Concern: The BLM should designate the Imperial County Sheriff's Office 

(ICSO) as the lead law enforcement agency.

Public Comment : The Imperial County Sheriff's Office should be designated as the 

lead law enforcement agency. The ICSO has primary law enforcement responsibility 

in Imperial County and, as such, should be the lead law enforcement agency at the 

ISDRA. Recent Off-Highway Motor Vehicle Recreation (OHMVR— green sticker) law 

enforcement grants to the Imperial County Sheriff resulted in increased involvement 

of the Sheriff at the ISDRA. Since then, a definite reduction in lawless behavior has 

been documented by the BLM. (#7226)

BLM Response: BLM maintains the lead agency role for the following reasons: 

a. ICSO has the same staffing level problems as the BLM. They have a large county

to provide enforcement to.

b. ICSO has an OHV team that provides assistance on off weekends but the team 

currently consists of 2-4 officers. 

c. Due to staffing and budget constraints they are only able to provide an increased 

level of assistance on specific dates during specific hours. The BLM is still 

providing the majority of the enforcement during all holiday events.

d. ICSO is not a resource protection agency.

ICSO is a tremendous asset to the overall enforcement effort and has been a great addition 

the BLM’s law enforcement strategy. ICSO, along with several other agencies, has helped 

the BLM provide the level of service and support desired for many years. Many BLM and 

Forest Service Rangers who work in the ISDRA have State Peace Officer status in the county 

granted by the sheriff. All arrests and a large percentage of citations written by the Rangers 

are processed through the Imperial County courts under state authority.

To address the issue of funding, ICSO did receive OHV dollars to fund their assistance 

during holiday weekends, but the BLM is still providing the majority of the funding for every 

other external agency. During holiday weekends the BLM, ICSO, and the California 

Highway Patrol (CHP) share a command role.

#72 Public Concern: The BLM sho uld use the most accurate and up -to-date 

information to establish law enforcement staffing levels.

Public Comment : Making sure that there are trained and equipped law enforcement 

personnel in the ISDRA works to the benefit of all. However, given that the visitor 

projections in the DEIS are flawed, it is difficult to determine exactly how many 
42

personnel are needed and at what time during the season those numbers need to be 

augmented or changed. As with visitor levels, I encourage the BLM to revisit 

estimates for law enforcement personnel once an accurate study of visitor levels, 

arrest statistics, injury reports, incident reports, and citations is completed. Another 

factor to consider as these levels are reviewed is the impact that the "Zero Tolerance" 

policy, which went into effect in April of 2002, has had on these statistics. (#7695)

BLM Response: The Proposed RAMP would continue to emphasize a co-operative 

approach to law enforcement. Local, State and Federal law enforcement officers, working 

together, would provide increased law enforcement. In addition, several management 

techniques would be implemented to increase law and order. These techniques include 

establishing two new tools. These tools are curfews and restrictions in areas of historic 

lawlessness and limiting alcohol use to established camp areas. Visitor use and incident data 

are currently monitored and will be used to evaluate the specific need for these tools and to 

develop the criteria for their use. These tools would be used as needed, but are not expected 

to be continuously required. Application of current laws, such as speed limits and reckless 

driving, will be used initially to address safety issues. Curfews and restrictions will be used 

as an additional tool when existing laws and actions are not producing a safe environment. It 

is anticipated that these actions would restore a safe family atmosphere at the Imperial Sand 

Dunes Recreation Area. Any temporary or permanent increases or changes in staffing would 

be considered based on that information.

#73 Public Concern: The BLM should increase the presence of law enforcement rather 

than creating new restrictions

Public Comment : With an adequate enforcement presence at the Dunes you would 

significantly reduce the concerns from being unmanageable to being managed 

appropriately. We don't need more restrictions; we need more presence of those who 

are responsible to enforce the existing laws and restrictions. This will ensure 

compliance in a manner that is practical and beneficial to everyone. (#212)

BLM Response: BLM is currently working with several agencies and various groups on 

finding ways to increase the law enforcement staff until lawless issues are addressed. BLM 

plans to continue the increased holiday enforcement efforts with the cooperation of several 

outside agencies including Imperial County Sheriff deputies and California Highway Patrol 

personnel. BLM is also working with ICSO to increase enforcement officers on offweekends. 

BLM will monitor incidents starting in 2003 to determine if more restrictive methods are 

needed. The information will be evaluated continually from 2003 on and additional 

measures can be implemented at any time based on incident trends beginning in 2004.

#74 Public Concern: The BLM should use vo lunteers to augment the law enforcement 

staff.

Public Comment : We support increased use of volunteers. The BLM El Centro 

Resource Area has a varying record of inclusion and reliance on volunteer efforts. A 

commitment to the use of volunteers and programs such as the Dune Patrol, the 
43

Junior Ranger Program, the Technical Review Team, and dune clean-up efforts is 

imperative. We strongly believe the amount of staff time expended on volunteer 

management and direction pays huge dividends: both in on the ground actions and 

management perceptions. The efforts of the organized OHV groups are underutilized 

due to the lack of the BLM's commitment to plan and organize volunteer support. 

(#8256)

BLM Response: Because of many liability and legal issues volunteers cannot issue citations 

and cannot be placed in harms way. However, the BLM would like to encourage people to 

volunteer and help provide eyes and ears in the ISDRA to help in reducing incidents.

#75 Public Concern: The BLM should not establish curfews which w ould merely shift 

problems into more remote parts of the ISDRA.

Public Comment : Curfews would only change the location of the gatherings from 

known, easily accessible and monitored locations to places farther out in the dunes 

where law enforcement officers cannot get in their current 4x4 vehicles. Rescue and 

enforcement efforts in these more remote locales would be difficult and costly. 

Failure on the part of the BLM to provide visitor services (rescue) to more remote 

gatherings could be cause for litigation in the event of injury or death that could be 

argued was proximately caused by this action. (#7887)

BLM Response: Part of the strategy involving a curfew would also address the problems of 

relocation. After reading the public comments on the DEIS, BLM has decided to continue 

with the increased enforcement efforts that were implemented in January 2002. During the 

2003 season the BLM will conduct specific monitoring to determine the success of this 

approach. If the results of the monitoring indicate that no significant reductions in visitor and 

employee safety have occurred, and no significant reduction in DUIs, assaults, and other 

serious incidents can be documented BLM will determine if stronger measures are needed 

such as those items identified as tools in the law enforcement toolbox (curfews and/or partial 

alcohol restrictions).

#76 Public Concern: The BLM should continue its zero tolerance law enforcement 

program to curb lawlessness in the hills rather than establish curfews.

Public Comment : I do not believe that the enforcement of curfews is needed at all. 

Enforcement of the Zero Tolerance law enforcement that was implemented on 1/1/2 of 

this year has shown much promise. This Zero Tolerance policy should be allowed to 

continue as long as it is working in the best interest of ISDRA. Curfews are only 

punishing those of us that are responsible Duners and not really taking care of the 

real problem which is the rowdy crowd that uses the Dunes as a place to party with 

their friends and get involve in lawless behavior. Using pinch points is a very 

effective way to get the message across to these lawless individuals and is supported 

by many of us in the OHV community. (#8530)

BLM Response: The Proposed RAMP would continue to emphasize a co-operative 

approach to law enforcement. Local, State and Federal law enforcement officers, working 
44

together, would provide increased law enforcement. In addition, several management 

techniques would be implemented to increase law and order. These techniques include

establishing two new tools. These tools are curfews and restrictions in areas of historic 

lawlessness and limiting alcohol use to established camp areas. Visitor use and incident data 

are currently monitored and will be used to evaluate the specific need for these tools and to 

develop the criteria for their use. These tools would be used as needed, but are not expected 

to be continuously required. Application of current laws, such as speed limits and reckless 

driving, will be used initially to address safety issues. Curfews and restrictions will be used 

as an additional tool when existing laws and actions are not producing a safe environment. It 

is anticipated that these actions would restore a safe family atmosphere at the Imperial Sand 

Dunes Recreation Area. There is a need to change the atmosphere that many of the “Party 

going” visitors to these areas adhere to. The goal is not to penalize all the visitors to these 

areas, but rather to restore these areas to the family oriented places they used to be.

#77 Public Concern: The BLM should allow alcoholic beverages in the ISDRA.

Public Comment : Alcohol Ban: Should be just like boating. Drinking in camp is 

OK. Give a DUI to drunk riders. (#168)

Public Comment : Alcohol abuse committed by a few OHV users does cause 

problems. However, banning alcohol use by responsible OHV users will only serve in 

moving the problems associated with alcohol abuse to other areas, such as in camp 

or further out into the dunes. This has the potential to increase confrontations 

between alcohol abusers and other visitors in a potentially more dangerous situation. 

We feel Zero Tolerance should be given a chance to work. We personally have 

witnessed its effectiveness in limiting and eliminating problems over the past year, 

particularly on the holiday weekends. (#7804)

BLM Response: Part of the strategy involving an alcohol ban or curfew would address the 

problems of relocation. After reading the public comments on the DEIS, BLM has decided 

to continue with the increased enforcement efforts that were implemented in January 2002. 

During the 2003 season the BLM will conduct specific monitoring to determine the success 

of this approach. If the results of the monitoring indicate that no significant reductions in 

visitor and employee safety have occurred, and no significant reduction in DUIs, assaults, 

and other serious incidents can be documented, BLM will determine if stronger measures are 

needed such as those items identified as tools in the law enforcement toolbox (curfews and/or 

partial alcohol restrictions). When considering the use of these tools the BLM will consult 

with Imperial County and other cooperative law enforcement agencies. After looking at all 

the data and considering other agency and outside input, BLM will make the final decision 

on implementation. Beginning in the 2004 season these measures may be implemented and 

or lifted at anytime based on the information gathered from the ongoing monitoring of 

incidents.

#78 Public Concern: The BLM should ban alcoholic beverages in the ISDRA.

Public Comment : I feel that there should be a complete alcohol ban at the Imperial 

Sand Dunes. Recreational driving and alcohol do not mix, never have and never will. 
45

It is obvious that the off-road people feel that in order to enjoy their play toys, they 

have to have alcohol in order to do so. (#918)

Public Comment: Banning alcohol is also an effective way to reduce the violence 

and bad behavior. Please keep the ban on alcohol in the final management plan. 

Alcohol has no place in the dunes. We have participated in many cleanups in the 

dunes, or many times we go search out things to find in the sand. 99% of the trash or 

objects left in the dunes are empty beer bottles! (#7226)

BLM Response: The Proposed RAMP would continue to emphasize a co-operative 

approach to law enforcement. Local, State and Federal law enforcement officers, working 

together, would provide increased law enforcement. In addition, several management 

techniques would be implemented to increase law and order. These techniques include 

establishing two new tools. These tools are curfews and restrictions in areas of historic 

lawlessness and limiting alcohol use to established camp areas. Visitor use and incident data 

are currently monitored and will be used to evaluate the specific need for these tools and to 

develop the criteria for their use. These tools would be used as needed, but are not expected 

to be continuously required. Application of current laws, such as speed limits and reckless 

driving, will be used initially to address safety issues. Curfews and restrictions will be used 

as an additional tool when existing laws and actions are not producing a safe environment. It 

is anticipated that these actions would restore a safe family atmosphere at the Imperial Sand 

Dunes Recreation Area. There is a need to change the atmosphere that many of the “party 

going” visitors to these areas adhere to. The goal is not to penalize all the visitors to these 

areas, but rather to restore these areas to the family oriented places they used to be.

#79 Public Concern: The BLM should reduce traffic accidents by requiring all 

licensed vehicles to remain within 50 feet of campsites and roads.

Public Comment : The "zero tolerance" plan has curbed many unwanted accidents 

and rowdiness. Additional wording to the effect: "no licensed vehicles are permitted 

more than 50 feet from campsites and roads" would greatly reduce traffic accidents, 

drunk driving, and the like. (#7831)

BLM Response: The street legal vehicles have the same right to operate in the ISDRA as 

Green Sticker vehicles. It is unclear to BLM how restricting licensed vehicles to within 50 ft. 

of roads and campsites is going to reduce accidents.

#80 Public Concern: The BLM should not penalize all OHV users for th e acts of a few 

by restricting use at Competition Hill.

Public Comment : I will devote this letter to what seems to be the real problem, and 

that is the violence and lawlessness at Competition Hill at night on holiday weekends. 

I have heard of some proposals to close or limit this and other areas to use. I feel that 

taking away this truly unique recreational area has the same logic as banning the 

sale of spray paint to everyone in the U.S. because a small handful of people use it for 

graffiti. The number of people causing problems truly is small. It may not seem so 

observing things late at night, but the fact is a small group instigates things and 

others follow who would not start things on their own. The individuals in question are 
46

not even there to use the Dunes but merely to "party." Very few even have an OHV of 

any kind and are only seen at night. These are local youths (teens and early 20s) who 

come in 4WD trucks and park in the mid to back rows. The front row is taken up by 

people who are there to race and you would be hard pressed to find a significant 

problem in that area. If the area is closed the legitimate users will suffer and the 

"Partiers" will merely go somewhere else unaffected by the mess they caused. 

(#6005)

BLM Response: There is a need to change the perception that Comp Hill and other similar 

areas are big party spots and that people can do whatever they want. BLM’s goal is not to 

penalize all visitors to these areas but rather to restore these areas to the family oriented 

places they used to be.

Infrastructure

#81 Public Concern: The revised RAMP should include a realistic assessment of 

budgetary constraints of the proposed plan.

Public Comment : Alternatives proposed should include a realistic assessment of 

budgetary constraints placed upon BLM, and their relationship to proposed actions. 

Unfunded mandates in this 475,000 acre area are, in reality, no mandates; the public 

should be aware of what is possible to do with the resources available. (#8278)

BLM Response: The Proposed RAMP management policies, plans and actions are based on 

best estimates of future budgets. Funding availability is difficult to predict, particularly for a 

10 to 15 year period. BLM has attempted to temper its desire to give the best management 

possible to the ISDRA with realistic budgetary projections.

#82 Public Concern: The BLM should not link agency funding and continued OHV 

use at the ISDRA.

Public Comment : I am concerned at the phrasing of page 52, Pp 2. [The statement] 

that services will be "discontinued permanently . . . until it can obtain funding," 

suggests that the area will be closed to visitors. Is that the intent? If so I feel that is a 

loophole, [that] opponents of the ISDRA have a way to shut the area down 

bureaucratically. (#8508)

BLM Response: Some levels of services are linked to Green Sticker funds and dollars 

collected from Fee Demo. The development of the business plan will address this issue 

further.

#83 Public Concern: The BLM should justify its claim that extending Gecko Road

would violate the ESA.

Public Comment : Page 2-4 Section 2.1.1 Gecko Road Extension. The DEIS states 

that extending Gecko road would violate the ESA, but there is no data to back this 

statement up. The area in question has been released from WSA 362. Extending 
47

Gecko road would provide more camping areas and thin out some of the 

overcrowding. (#8267)

BLM Response: A proposal to extend Gecko Road south would likely result in a jeopardy 

opinion from the U.S. Fish and Wildlife Service because of potential impacts to the Peirson’s 

milk-vetch. This opinion is based upon conversations between BLM biologists and U.S. Fish 

and Wildlife personnel. 

#84 Public Concern: The BLM should grade the Wash Road more often.

Public Comment : DRAMP Page 81, Wash Road graded regularly: My 

understanding is that the fees were supposed to be used in part to grade the road. It 

hasn't been graded as often as I would like, though. I noticed in the budget that the 

estimated yearly cost is $689/mile, and that the first year estimated cost is $689. Does 

this mean that only the 1st mile will be graded? How often is "regularly?" Personally, 

I think it should be graded at least before every big weekend. (#7595)

BLM Response: BLM grades roads as often as need, funding and manpower allows. 

#85 Public Concern: The BLM should provide parking on the north side of Highway 

78.

Public Comment : Another issue would be to provide hikers and environmentalists a 

place to park their vehicles on the north side of Highway 78 so they would have a

safe place to enjoy the dunes. (#8039)

BLM Response: No facilities are proposed in the North Algodones Wilderness Area. 

Limited parking is available at the Osborne Overlook on the south side of Highway 78.

#86 Public Concern: The BLM should recogniz e that building a ranger station at 

Osborne Overlook will compromise the natural, undeveloped character of the area and 

should not be built.

Public Comment : One part of the report suggests building a multi-million dollar 

facility at the top of Osborne Overlook. While many visitors brave the elements in this 

particular area for a short duration, the wind and blowing sand make this a poor 

choice for a BLM facility. Since this facility would be used to capacity only about 15 

days per year, the amount of money being considered for this project could be much 

better allocated to increase law enforcement and to reduce the congestions in 

camping areas and the dunes. (#7829)

BLM Response: Based on many factors, including public comments received, the Preferred 

Alternative for the FEIS proposes not to construct a ranger station at Osborne Overlook. A 

new ranger station is instead to be constructed at the present site on Gecko Road. BLM does 

plan to utilize the Osborne Overlook area during peak holiday weekends. The FEIS and 

Proposed RAMP reflect this change.
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1

APPENDIX B

MONITORING REPORT
2

TABLE OF CONTENTS

Introduction 3

Special Status Plant Monitoring and Management 3

Peirson’s Milk-vetch 3

Figure 1. Schematic of Milk-vetch Monitoring Plan 4

Peirson’s Milk-vetch Monitoring Surveys 5

Ground Moisture/Precipitation Monitoring 8

OHV Use Monitoring 8

Calibration Studies: OHV Use and Rainfall 9

Effects of OHV Use Studies 9

Correlative Study 9

Experimental Study 1 11

Experimental Study 2 12

Peirson’s Milk-vetch Biological Studies 12

Development of Milk-vetch Models 12

Management Options 13

Adaptive Management 13

Monitoring/Study Implementation Schedule and Cost 15

Algodones Dunes Sunflower Monitoring 16

Sand Food Monitoring 16

Psammophytic Vegetation Monitoring 17

Desert Microphyll Woodland Monitoring 17

Vegetation 17

Bird Populations 17

Colorado Desert Fringe-toed Lizard 17

Flat-tailed Horned Lizard 19

OHV Use Monitoring 20

Visitor Use Monitoring 21

Weather Stations 21

Additional Funding 22

Literature Cited 23
3

Introduction

This appendix provides the methodology that will be used to monitor species and habitats of 

concern in the ISDRA. Through research, monitoring, and analysis of the monitoring data, 

BLM will determine the impacts to species and habitats of concern due to recreational use of 

the ISDRA, and use this information to make management changes, if necessary. 

Management of recreational use throughout the dunes, especially in the adaptive 

management area (AMA), will be evaluated periodically in light of the results of this 

research and monitoring and revised as needed. The monitoring information will be used to 

make annual changes in the number of permits that will be issued for use of the AMA and to 

determine whether and when the management plan for the ISDRA needs to be amended. 

This monitoring/study plan is a dynamic document. Based on periodic reviews of the quality 

of the data collected and the usefulness of the data for making management decisions, it will 

be amended as necessary in order to ensure that the most important information is available 

to the manager for decision-making.

Special Status Plant Monitoring And Management

The Algodones Dunes support numerous dune-endemic plants. Of special interest in terms of 

conservation are species whose distribution is restricted to the Algodones Dunes or whose 

status indicates that special management is necessary to ensure the ongoing persistence of the 

species. Three dune-endemic plants will be the target species of an intensive monitoring 

effort in the Algodones Dunes: 

- Peirson’s milk-vetch - Astragalus magdalenae var. peirsonii (ASMAP)?

- Algodones Dunes sunflower - Helianthus niveus ssp. tephrodes (HENIT)?

- Sand food - Pholisma sonorae (PHSO)

Peirson’s milk-vetch will receive the highest level of attention, since this species was 

federally listed as threatened primarily due to threats posed by OHV activity in the 

Algodones Dunes. The monitoring and research pertaining to ASMAP will provide 

information that may be useful in managing all target plant and animal species in the dunes. 

Peirson’s Milk-vetch (ASMAP)

A flow chart of the general management scheme that will be used to adaptively manage the 

ISDRA to protect Peirson’s milkvetch while providing the opportunity for recreation 

activities is provided as Figure 1.
4

Figure 1. Schematic of Peirson’s milk-vetch monitoring and management plan.

Management Areas (Oval 1). The ISDRA will be managed in 9 units, 7 of which (listed 

below) support the target special status plants. This is the basis on which management will 

be applied. Each Management Area will be subject to an initial management option, which 

will be subject to change based on the status of milk-vetch in that unit and the results of 

studies. 1

Management Area Initial Management Option

Mammoth Wash Open to OHV use

North Algodones Wilderness Closed to OHV use

Gecko Open

Glamis Open

Adaptive Management Area (AMA) Open to 525 riders/day

Ogilby Open

Buttercup Open

Surveys and Monitoring (Box 2). The monitoring surveys will illustrate the “state” of system 

variables including ASMAP abundance and distribution, ground moisture/ precipitation, and 

OHV use. These three state variables will be analyzed to test predictions based on 

management options that are currently being implemented and to provide information on 

 

1 Changes to the Adaptive Management Area will be made annually (after an initial period of sampling— see text), as 

necessary, through adjustments in the number of permits issued. If changes in OHV use and/or distribution are necessary in 

the other management areas, these would be made through the plan amendment process in consultation with the U.S. Fish 

and Wildlife Service.

Surveys and Monitoring

Milk-vetch Number

OHV Use Index 

Precipitation/Moisture

Calibration studies

-OHV

-Rainfall

Management 

options i

Effects of OHV 

studies

Milk-vetch biology studies

Management 

Areas i=1 to 7

 1

2

3

4

5

1

Development of milk-vetch models 6
5

which management option should be chosen in the future. These surveys will allow a 

statistical inference to be made to each management area. The initial prediction, based on 

BLM’s understanding of current milk-vetch distribution and abundance, is that milk-vetch 

abundance and distribution in each management area will not change between years (that 

have comparable levels of rainfall above or equal to the long-term mean) given the proposed 

management options (see Box 1). 

ASMAP SURVEYS

For the first four years of monitoring plan implementation, annual estimates of density and 

population size will be made in each of the seven management areas that support ASMAP. 

These estimates can also be combined into a single estimate for the entire ISDRA using the 

appropriate formula for stratified random sampling. Milk-vetch sampling will be conducted 

in the spring of each year, beginning at the time most ASMAP individuals are in flower. 

Based on monitoring between 1998 and 2002, this period begins around the last week of 

March. 

Following the collection of four years of density estimates, the frequency of monitoring may 

be reduced to correspond to years in which the precipitation that occurs between July and 

November is sufficient to ensure precipitation levels that meet or exceed the long-term mean 

(see ground-moisture/precipitation section below) of precipitation levels between July and 

March. The reason for reducing the frequency of monitoring to good-rainfall years is that the 

abundance of ASMAP in any spring is highly correlated with the amount of rainfall in the 

growing season immediately preceding that spring (Willoughby 2001; Willoughby, 

unpublished data). Between wetter years, the milk-vetch population declines as plants die 

and are not replaced due to lack of germination. Monitoring during poor rainfall years could 

result in a lower encounter rate for ASMAP plants that is not reflective of the species’ status. 

Monitoring during poor rainfall years could, however, provide information concerning the 

persistence of adult plants and the relative importance of these plants to seed bank 

contributions. 

Sampling Objectives: Although all 3 target plant species will be sampled, the following 

sampling objectives are based on ASMAP. It is anticipated that similar precisions will also 

be obtained for the other 2 species (Algodones Dunes sunflower and sandfood). There are 

two sampling objectives, one for the yearly estimates and one for change detection. For the 

yearly estimates, sampling will be designed to achieve estimates that are within 30% of the 

true total population size at the 95% confidence level for each of these management areas. 

For change detection, the sampling objective is to detect a 30% change between two averageto-above-average rainfall years with a statistical power of 90% and a false-change (Type I) 

error rate of 10%. 

Sampling methodology. The highly clumped nature of ASMAP makes the use of belt 

transects (long, narrow quadrats) mandatory in order to achieve reasonably precise estimates 

(Elzinga et al. 1998 and 2001). Pilot sampling was conducted on ASMAP and HENIT in 

2001 and on ASMAP, HENIT and PHSO in 2002 using belt transects run due west-east 

across the dunes. The belts ranged from 5.8 km to 15.9 km long depending on the extent of 
6

the dunes crossed by each transect. In 2001 the number of plants of each species was 

recorded separately in 1m wide belts on each side of the transects, so that separate 

coefficients of variation could be calculated for both 1m and 2m wide belts. Coefficients of 

variation (CVs) were unacceptably high for both belt widths, and samples of 34 belts yielded 

imprecise estimates of population size (Table 1 shows the CVs and precisions for ASMAP 

for different belt widths). Accordingly, in 2002 pilot sampling was expanded to add belt 

widths of 5m and 10m. The 2002 sampling included PHSO in addition to ASMAP and 

HENIT. In 2002 the number of plants of each species was recorded separately in 1m, 2m, 

5m, and 10m wide belts on one side of each of the transects, so that separate coefficients of 

variation could be calculated for belts of all 4 widths. As expected, CVs progressively 

decreased and precision progressively improved as the belt widths were increased, but even 

the 10m belt width still resulted in a rather high CV, and a sample of 34 belt transects 

resulted in a population estimate for ASMAP of +/- 62%. These pilot data indicate that even 

wider belt widths should be used if practical to reduce the CV even further and minimize the 

number of sampling units that will be needed to achieve sampling objectives. 

One generally strives for a sampling design that results in a CV of less than 1.0, but because 

of the very scattered nature of its occurrences this may not be a practical goal for ASMAP. It 

is important to note, however, that these pilot data were collected using belts oriented with 

their long sides in a west to east direction (they were oriented in this direction because the 

pilot data were collected ancillary to a different monitoring study that began in 1998). Belt 

transects are most efficient when they are oriented to follow a gradient that is known to be 

related to the attribute being sampled. Both ASMAP and HENIT occur in bowls at the 

bottom of SE facing slipfaces and on the gentle NW-facing slopes that run SE from the bowls 

(Phillips et al. 2001 and 2002; personal observations). The two species gradually disappear 

as the NW-facing slopes approach sand ridges. Thus, the plant species are responding to the 

NW-SE gradient consisting of a repeating pattern of relatively gentle NW-facing slopes, 

ridges, slipfaces, and bowls. Belts, therefore, that are oriented in this same NW-SE direction 

should prove to be more efficient in terms of reducing sampling error than W to E belts. 

Table 1. ASMAP coefficients of variation (standard deviation divided by mean) and 

precisions expressed as 95% confidence intervals from a sample of 34 belt transects. CVs 

and precisions for the 1m belt width are the average of two samples in 2001 and one sample 

in 2002. Those for the 2m belt width are the average of 1 sample in 2001 and one sample in 

2002.

Belt width Coefficient of Variation

Precision (+/- percent of 

mean)

1 m 2.659 92.78%

2 m 2.320 80.94%

5 m 1.984 69.24%

10 m 1.769 61.73%

A belt width of 25m is likely the widest practical width for ASMAP. Although belt widths as 

wide as 25m are problematic for some species, particularly in dense vegetation, the size of 

ASMAP individuals, coupled with the sparse vegetation in the dunes, make belts this wide 

practical. 
7

Belt transects will be positioned using a restricted random design (Elzinga et al. 1998 and 

2001) within each of the 7 management areas listed above.

Transects will be traversed in a NW to SE direction corresponding to the dune gradient 

discussed above. Baselines will be established at the NW edges of each of the management 

areas. An initial sample of 10 belt transects will be taken within each of the management 

areas. To accomplish this, the portion of the baseline that lies above the population to be 

sampled will be divided into 10 equal-sized segments. Within each of these segments, a 

single belt transect will be randomly positioned. The resulting 10 transects will extend the 

length (NW-SE) of the MA. The means and standard deviations derived for ASMAP will 

then be calculated and used to calculate the sample sizes required to achieve estimates of 

30% of the mean. Additional transects will be added to the previous 10 to achieve this 

sampling objective. The additional transects will also be added using a restricted random 

design. This will be accomplished by dividing the same baseline used to position the initial 

10 belts into the number of segments required to position the additional belts. Each 

additional belt will then be randomly positioned within each of the new segments, except that 

no additional belt will be placed in the same position on the baseline as one of the initial 10 

transects (i.e., sampling will be without replacement). 

Once established, the same transects will be sampled in succeeding years. This will be 

accomplished by the use of global positioning system (GPS) units. Many waypoints for each 

transect will be entered into the GPS units to ensure that observers walk the same transects 

each year. 

Bias resulting from the edge effect associated with the use belt transects will be controlled by 

the following rule: plants with rooting parts touching the left (NE) side of the boundary of 

each belt transect will be counted in, while those touching the right (SW) side of the line will 

be counted out.

The following information will be collected for ASMAP: (1) total number of individuals 

observed; (2) number of flowering individuals; (3) number of non-flowering individuals; (4) 

number of individuals older than 1 year (this can be determined by the presence of basal 

leaf/branch scars); (5) number of individuals with apparent physical damage from OHVs; and 

(6) number of individuals with damage from other sources (e.g., insects). This information 

will be recorded in 25m segments along belts, which will allow comparison of information 

collected in 25m x 25m subplots with OHV use monitoring, discussed below. The GPS 

coordinates of the beginning of each 25m x 25m subplot containing plant species will also be 

recorded. 

Analysis of Peirson’s milk-vetch monitoring: The population estimates for ASMAP within 

each of the management areas will be graphed by year with error bars corresponding to 95% 

confidence intervals.

For each management area comparisons between densities in two average-to-above-average 

rainfall years will be made by means of paired t tests. 
8

Ground Moisture/Precipitation Monitoring

Precipitation in the dunes will be measured by means of the two existing remote area weather 

stations (RAWS) and--once installed--by the additional five RAWS. Precipitation data for 

these stations will be collected for each month of the year. 

Ground moisture will be monitored in each 25 m plot along each transect during each plant 

survey. This information will be compared to milk-vetch abundance and distribution as well 

as to weather data.

OHV Use Monitoring

OHV use levels will be estimated by means of aerial photography, taken yearly. Sixteen air 

photo transects were established throughout the dunes in 1998 in order to obtain a sample of 

the distribution and intensity of OHV use in the dunes through the measurement of vehicle 

tracks. The aerial photographs obtained from these transects are at a 1:7000 scale, allowing 

the detection of vehicle tracks. These transects were flown on Easter weekend 1998 and reflown on Easter weekends in 1999, 2000, and 2001 (because of the ephemeral nature of 

vehicle tracks in sand, it was necessary to take the photographs during a weekend of 

relatively high vehicle use). The location of these air photo transects is shown in Willoughby 

2000, along with the results of vehicle track frequency measurements for 1998. 

The photographic information collected in 1999, 2000, and 2001 will be mapped and 

assessed for changes in use-levels and use-patterns.

In one year during the first four years following RAMP implementation, aerial photography 

will be obtained to achieve complete coverage of the dunes. This photography will be taken 

during three heavy OHV-use weekends in one recreation year (a recreation year begins in 

October of one calendar year and runs through Easter of the following calendar year). 

Photographs will be collected during Easter, Thanksgiving, and Presidents’ Day weekends, 

which are historically high-use weekends. OHV use will be measured on these photographs 

using the methodology discussed below. Following analysis of these data, a determination 

will be made as to which high-use weekend provides the best index of OHV use or whether 

future aerial photography should be rotated between two or all three of these high-use 

weekends. Following the initial four-year period, aerial photography will be obtained for one 

high-use weekend per year.

Aerial photographs will be sampled by means of a grid of points to estimate the cover of 

vehicle tracks in the dunes. The size of the grid and number of points per transect will be 

determined based on pilot sampling to meet the sampling objective described below. Future 

aerial photographs will be registered so that sampling grids can be placed in the same area in 

each year. 

The transects and 25 m segments used during plant monitoring (described above) will be 

overlaid on aerial photographs to allow comparison of OHV-use levels and plant abundance 

and condition.
9

Based on the above analyses, the calibration study (see Box 3, described below) and general 

assessment of the photographs, aerial photographs will be used to produce GIS maps 

depicting areas of the dunes subject to high, medium, and low levels of use. These maps will 

be compared over time to allow assessment of changes in use intensity or use patterns over 

time.

Sampling Objective: Sampling will be designed to achieve yearly estimates of OHV track 

cover that are within 30% (relative) of the true OHV track cover at the 95% confidence level 

within each of the 9 management areas. Sampling will be designed to allow mapping and 

quantification of “high,” “medium,” and “low” use areas within each management area. A 

methodology for determining high, medium, and low use areas will be developed in 

coordination with the FWS. It is unlikely this sampling objective can be met for the 

wilderness area since the OHV track cover there will likely be extremely low. This sampling 

objective may be modified based on pilot sampling. 

Calibration Studies: OHV Use and Rainfall (Box 3):

Since we are not able to estimate OHV use or rainfall directly for the whole dune area, we 

must rely on indices: the number of tracks from aerial photos and a measurement of ground 

moisture in discrete areas throughout the dunes. To understand what these indices mean in 

terms of true OHV use, calibration studies will be performed. For the OHV index, a known 

number of OHV-hours will be run in a replicated sample of un-tracked areas. The area will 

then be aerially photographed to calibrate the track counts with a known number of OHVhours. This study may be conducted concurrently with the experimental study on OHV 

Effects (below) to facilitate both studies. Using this methodology, low, medium, and highuse areas will be defined in coordination with FWS. Techniques for calibration of rainfall 

with ground moisture levels throughout the dunes have not been developed; however, 

ground-moisture levels will be measured during surveys and the potential for calibration 

studies be evaluated over time. 

The Effects of OHV Use on Peirson’s Milkvetch: Inferential and Experimental Studies. 

Correlative Study within the AMA

The densities of ASMAP, HENIT, and PHSO (number of plants/hectare) will be estimated 

for the entire AMA, for a 1 km2 control area within the AMA, and for a 1 km2 treatment area 

within the AMA in each of the three years following implementation of the RAMP. The 

treatment and control areas will be selected subjectively, subject to the following 

considerations. The treatment area will be selected to function in a manner similar to the key 

area concept in rangeland management. As defined by the Society for Range Management 

(1998), a key area is:

A relatively small portion or a pasture of management unit is selected because of its location, 

use or grazing value as a monitoring point for grazing use. It is assumed that key areas, if 
10

properly selected, will reflect the overall acceptability of current grazing management over 

the pasture or unit as a whole. 

Holechek (1988) and Holechek et al. (1998) point out that the key area concept has 

been highly useful to managers in evaluating the effects of grazing on rangeland 

vegetation. It is in wide use and is an accepted practice on Bureau of Land 

Management, Forest Service, and private rangelands (Habich et al. 1996). The 

concept should apply equally well to the evaluation of the effects of OHV use on 

ASMAP, HENIT, and PHSO. Just as for key areas in rangeland management, the 

treatment area will be selected to best reflect the effects of OHV use in the entire 

AMA. The control area will be selected to be as similar as possible in terms of 

habitat characteristics and weather to the treatment area.

The control and treatment areas will be rectangular in shape, with the long side of the 

rectangles oriented along the NW-SE dune gradient (discussed above under yearly 

monitoring for ASMAP, HENIT, and PHSO. The treatment and control areas will be 200m x 

5000m in size and shape. An area 220m x 5020m in size, encompassing the control area 

with 10m added to each side of the rectangle to eliminate edge effect, will be signed closed 

and patrolled on a regular basis by law enforcement personnel. The treatment area will 

remain open to OHV use. The NW-SE orientation will incorporate more potential ASMAP, 

HENIT, and PHSO habitat within the control and treatment areas than would other 

orientations. Belt transects will also be used within the 1 km2 AMA treatment and control 

areas, but an attempt will be made to completely census the treatment and control areas at 

least for ASMAP and HENIT. This would be accomplished by counting all plants of these 

species in contiguous 25m wide belts. If practical, PHSO will also be completely censused. 

Monitoring in the first year following implementation of the RAMP will determine whether 

complete censuses are practical.

Estimates for the treatment and control areas will be compared for each year. Comparisons 

will also be made between the responses of ASMAP, HENIT, and PHSO in the AMA as a 

whole and in the treatment area. These comparisons will be used to determine if the 

treatment area is adequately reflecting the effects of use in the AMA. If not, then a new 

treatment area will be selected or another treatment area added.

An attempt will be made to conduct actual censuses of the three species in the 1 km2 control 

and treatment areas of the AMA. If this proves to be practical, then there will be no sampling 

error associated with the population sizes measured for these two areas. If this is not 

practical, sampling will be designed to achieve yearly estimates that are within 20% of the 

true total population size at the 95% confidence level for each area. The objective for change 

detection will be to detect a 30% change between two average-to-above-average rainfall 

years with a statistical power of 90% and a false-change (Type I) error rate of 10%. The use 

of the control and treatment areas within the AMA is discussed further under a separate 

heading, below.
11

Comparative Evaluation Between Milk-vetch Surveys and OHV-Use Surveys

As described in the ASMAP survey section (Box 2) 25m x 25m subplots will be established 

along milk-vetch survey belt transects. These subplots will subsequently be identified on 

aerial photographs developed for OHV monitoring. Milk-vetch abundance will be compared 

to OHV use levels.

The correlative studies described above allow inferences to be made regarding effects of 

OHVs on ASMAP. In addition to the correlative studies described above, a manipulative

study is necessary to quantify the effects of OHV use on the reproductive capability and 

persistence of milk-vetch plants. 

Experimental Study 1

Experiment number 1 will conducted during on two separate occasions: (1) in the spring of a 

year that experiences rainfall at or above the long-term mean, and (2) in the spring of a year 

that experiences rainfall below the long-term mean. The experiment will be conducted twice 

under different conditions to ascertain whether the effects of OHV use are different under 

different weather regimes. At least eight 200 m x 200 m plots will be selected and subdivided into four 100 m x 100 m treatment plots. Four treatments (no, low, medium, and 

high OHV use) will be applied, with 8 replications for each treatment.

The definition of use categories will come from the OHV correlative study (described under 

Box 3) to make sure these are relevant treatment levels. Each plot will be censused for milkvetch, before and after treatment is applied, and two months following treatment. During the 

census, the following variables will be measured: (1) the number of ASMAP individuals and 

ratio of seedlings to adults and (2) the number of plants with evidence of vehicle damage.

Analysis of data:

The null hypothesis is that there will be is no treatment effect. The alternative hypothesis is 

that there will be an ordered treatment effect. 

A randomized complete block design will be used, with eight 200m x 200m plots, each subdivided into four 100 m x 100 m sub-plots placed in different areas of the dunes. The reason 

for blocking is to remove spatial variability between blocks from the analysis. 

Analysis will be on the before-after differences in the three variables (number of ASMAP 

individuals, ratio of seedlings: adults, and number of ASMAP plants with evidence of vehicle 

damage). Results will be displayed graphically showing mean difference by treatment with 

error bars corresponding to 90% confidence intervals. Effect sizes will be measured and 

evaluated for a difference. Each variable will also be analyzed using an analysis of variance 

(ANOVA) that accounts for the effects of blocking. The experiment-wise Type I error rate 

will be set at 0.10. A P value from the ANOVA less than 0.10 would also indicate that there

is a treatment effect. Post hoc tests will then be conducted to determine which pairs of 

treatments differ. These post hoc tests will control for the experiment-wise error rate.
12

Experimental Study 2

The second experimental study will quantify the impact on individual plants from being run 

over by a vehicle. The study will follow the general guidelines of a previous study 

conducted by Pavlik (1979) but will be conducted with a larger sample size.

Milkvetch Biological Studies (Box 5): 

Additional biological information regarding the life-history of ASMAP is necessary to model 

the population, predict the population response to management options, and effectively 

manage the population. Information that is necessary to determine the effect of management 

options on this species include studies that address the questions listed below. These studies 

will be conducted by BLM, other Federal or State agencies, non-governmental organizations, 

or universities as funding is secured. These studies will address the following questions:

- What are the relative contributions of adult and seedling milk-vetch plants to the 

seedbank? 

- Are seeds produced by milk-vetch seedlings viable? 

- How much ground moisture is required to stimulate germination of milk-vetch seeds?

- How long do milk-vetch seeds remain viable?

- For how many years do adult milk-vetch plants remain reproductive?

Development of Milk-vetch Models (Box 6): 

Our current understanding leads us to believe that two key variables, rainfall (moisture) and 

OHV use contribute to ASMAP dynamics in the Algodones Dunes. The information 

obtained from the surveys and studies listed above will be used to evaluate several models of 

ASMAP dynamics as they pertain to these variables. The area occupied by ASMAP may 

increase or decrease in response to OHV use, precipitation, or a combination of these factors. 

Each model will predict the impact of an action, which will result in some expected return in 

terms of the objective. Initially, each model will be given equal weight. Over time, each 

model of ASMAP dynamics will receive different weight based on monitoring and study 

results. 

Management Options (Box 1):

The initial management option for the RAMP will be unlimited OHV use in 5 Management 

Areas, continued closure of the North Algodones Dunes Wilderness to OHVs, and 525 

vehicles per day permitted use in the AMA. This management option will be assessed by 

studies and monitoring of milk-vetch populations to better understand the dynamics between 

moisture (precipitation), varying levels of OHV use, and milk-vetch reproduction, numbers, 

and distribution. In the future, management of each of these Management Areas may change 
13

in response to identified changes in the milk-vetch status in each unit and information gained 

from the aforementioned studies. Possible management options include those based on a 

permit system that would allow a specified level of use (high, medium, low, no use), 

temporally based closures or limitations (open during some months or years, closed in 

others), recognition and management of subunits within a management area, and/or increased 

education and outreach to OHV users to avoid certain areas. Most of these changes to 

management areas other than the Adaptive Management Area, discussed below, would 

require an amendment to the ISDRA Plan. 

Adaptive Management

Adjusting the number of permits in the Adaptive Management Area: 

No change in the number of riders permitted to use the AMA will be made until 4 years of 

monitoring and research data have been collected and analyzed. It is anticipated that 

differences in density of 30% percent between a baseline year and a subsequent year with 

comparable rainfall would be both detectable and biologically significant. If this level of 

change in milk-vetch abundance, distribution, or density occurs within the AMA, the BLM 

may adjust the management option in this Management Area. If a decline of this magnitude 

is observed, BLM may adjust management to a management option that provides increased 

protection for ASMAP. If an increase of this magnitude is observed, BLM may adjust 

management to a management option that allows increased recreational use of the area. No 

change in the number of riders permitted to use the AMA will be made until 4 years of 

monitoring and research data have been collected and analyzed. Several sources of 

information will then be used to determine if and when to adjust the number of OHV permits 

within the AMA: (1) comparison of the densities of ASMAP, HENIT, and PHSO in the 

control and treatment areas (correlative study within the AMA); (2) between-year 

comparison of the use patterns and use levels within the AMA; and (3) results of OHV 

impact studies described above. 

Adaptive Management in other Management Areas:

Monitoring and studies will be conducted during the first four years of ISDRA Plan 

implementation in accordance with the Implementation Schedule below. After this four-year 

period, BLM will reinitiate Endangered Species Act (ESA) Section 7 consultation with the 

U.S. Fish and Wildlife Service so that scientific information collected as part of this 

monitoring/study plan can be fully integrated into the ESA Section 7a(2) analysis for this 

action. This consultation will also allow revision of the interim threshold, identified below, 

if sufficient information has been obtained and identification of the adaptive management 

strategy to be used if milk-vetch populations decline below threshold levels.

Interim threshold: If the population of Peirson’s milk-vetch in any of the management areas 

declines by more than 50% in two years of average to above-average growing season 

precipitation, BLM will re-initiate Section 7 consultation with FWS.
14

If BLM is unable to conduct monitoring and studies scheduled during the first four springs of 

RAMP implementation, BLM will re-initiate consultation with FWS.
15

Peirson’s Milk-Vetch Monitoring/Study Implementation Schedule and Cost

 FY 2004 FY 2005 FY 2006 FY 2007 FY 2008

Precipitation monitoring (installation 

of weather stations and development of 

data base)

X

$125,000

ASMAP Monitoring Surveys* X

$140,000

X

$140,000

X

$140,000

X

$140,000

*

$140,000?

Dune-wide aerial survey (OHV usepatterns)

and analysis (including mapping)

X

$186,000

X

$62,000

OHV Use Calibration Study (cost 

included with Experimental Study 1) X

Experimental Study 1 (OHV Use) ** X

$30,000

**

$30,000

Experimental Study 2 (OHV Use) X

$15,000

AMA correlation study (OHV Use) X

$10,000

X

$10,000

X

$10,000

X

$10,000

X

$10,000

Survey/aerial photography comparison 

(OHV Use vs. Milk-vetch Abundance 

in 25m Sub-Plots

X

$10,000

X

$10,000

X

$10,000

Compilation and mapping of 1999, 

2000, 2001 OHV use data

X

$10,000

Development of Milk-vetch Models X

$20,000

Coordination with FWS Regarding 

Threshold Adjustment X

Estimated Cost for Fiscal Year $160,000 $305,000 $346,000 $175,000

$102,000 

or 

$242,000

* After the first three years, dune-wide ASMAP surveys will be conducted during “wet” years, 

likely every 4-5 years.

** The “dry year” repeat of Experimental Study 1 will be conducted in the first dry year after 2007.

Note: There is flexibility over which studies are funded during which fiscal years. The table above 

assumes that Experimental Study 1 will be conducted in FY 2005, that dune-wide aerial surveys will 

be flown during Thanksgiving weekend, Presidents’ Day weekend, and Easter weekend of 2005-

2006, and that Experimental Study 2 will be conducted in FY 2007. Other combinations are possible 

depending on funding availability for particular fiscal years.
16

Algodones Dunes Sunflower (HENIT)

Algodones Dunes Sunflower will be monitored in conjunction with Peirson’s milk-vetch 

(ASMAP). Estimates of population size and the other parameters listed under the description 

of ASMAP surveys will also be made for HENIT using the same methodology described for 

ASMAP, including a belt transect width of 25m, except that different stage classes than those 

employed for ASMAP will likely be necessary due to the different morphology of HENIT. 

The OHV use monitoring described under the ASMAP section of this monitoring/study plan 

will also be used to determine correlations between levels of OHV use and abundance of 

HENIT. Experimental studies 1 and 2 described under the ASMAP section are primarily 

directed toward determining the effects of OHV use on ASMAP, but to the extent HENIT 

can be included in these studies it will be. In other words, the same measurements performed 

on ASMAP will also be performed on those HENIT individuals present in the ASMAP study 

plots. It may not be possible, however, to locate these study plots in a manner that 

incorporates sufficient numbers of both species to achieve similar levels of statistical 

confidence in the results for both species. These studies will be designed with the primary 

objective of determining the effects of OHV use on ASMAP (see study objectives in the 

ASMAP section), with the result that statistical confidence in the results for HENIT may be 

lower (perhaps much lower) than those for ASMAP.

Biological studies of HENIT would also yield valuable insight into the ecology of this 

species and BLM will work with universities, other agencies, and non-governmental 

organizations to encourage the funding and implementation of these.

Sand Food (PHSO)

Sand food will also be monitored in conjunction with Peirson’s milk-vetch (ASMAP). 

Estimates of population size will be made for PHSO using the same methodology described 

for ASMAP, except that a narrower belt width will likely be necessary for PHSO owing to its 

more cryptic nature (it is anticipated that a belt width of 5m or 10m will be used for this 

species) and the identification of stage classes is not possible for this species (the counting 

unit is an inflorescence; the rest of the plant is hidden below the surface of the sand). The 

OHV use monitoring described under the ASMAP section of this monitoring/study plan will 

also be used to determine correlations between levels of OHV use and abundance of PHSO. 

Experimental studies 1 and 2 described in the ASMAP section will not be applied to PHSO 

because— for the most part--the latter species does not occupy the same areas of the dunes as 

the former.

Biological studies of PHSO would also yield valuable insight into the ecology of this species 

and BLM will work with universities, other agencies, and non-governmental organizations to 

encourage the funding and implementation of these.

PSAMMOPHYTIC VEGETATION

Both the cover and density of perennial plants will be estimated annually by means of line 

intercept transects run perpendicular (or, along the left edge of the belt transect, if desired) to 
17

each of the belt transects described above at systematic intervals along each belt. A line 

intercept transect length of 50m will be used during pilot sampling; this length is subject to 

change depending on how well a transect of this length intercepts the variety of perennial 

plants present at each sampling location. These transects will be positioned systematically 

with a random start at 1 km points along each of the belt transects. Along each transect, the 

distance intercepted by the line will be recorded by species. This will result in an estimate of 

cover for each species as well as an estimate for total vegetation cover. Additionally, the 

width of each species intercepted will be measured by means of a meter stick or other 

measuring device placed perpendicular to the line intercept transect at the plant’s widest 

point. These widths will be used to estimate the density of each perennial plant, using 

methods described in Lucas and Seber (1977). 

Sampling Objective: Sampling will be designed to achieve yearly estimates of cover that 

are within 50% (relative) of the true vegetation cover at the 95% confidence level within 

each of the 5 sampling areas. This sampling objective may be modified based on pilot 

sampling.

Analysis: Changes in total vegetation cover and the cover of at least the most dominant 

species will be analyzed in a manner analogous to that described for special status species, 

above.

DESERT MICROPHYLL WOODLAND VEGETATION

Monitoring of Desert Microphyll Woodland vegetation will be conducted annually, but 

monitoring of specific areas will be done on a five-year rotation using the protocol attached 

at the end of this appendix. 

BIRD POPULATIONS IN MICROPHYLL WOODLAND

Monitoring of bird populations in microphyll woodland will be conducted in accordance with 

the protocol attached at the end of this appendix.

COLORADO DESERT FRINGED-TOED LIZARD

In 2001, 50 survey transects were completed for spring and fall in order to estimate the 

density of Colorado Desert fringe toed lizards (Uma notata) in a comparison of open and 

closed areas in terms of OHV use. The Algodones Dunes Wilderness Area was used as a 

control, while the open area to the south was used as a treatment. Using the grid established 

by the WESTEC Study of 1977 (WESTEC 1977), 0.45 mile square cells on the grid were 

selected using simple random sampling after the elimination of habitat not entirely consistent 

with Uma notata, i.e., microphyll woodland, creosote bush scrub, and any cells within 0.45 

miles of a road (Gecko Road and State Highway 78).
18

The first 60 Cells were then numbered (south to north in closed area, north to south in open 

area) in a snaking pattern before simple random sampling was applied. Transects were 0.45 

mile long and 10m wide belts. Surveyors were evenly spaced, and navigated the transects 

using Garmin III global positioning system units on NAD 83 Map Datum from west to east 

using the northwest to northeast grid lines. Transects were alternated from open to closed 

areas in order to avoid weather bias, and were also completed when surface temperatures 

were at or between 35-44 degrees Celsius. Transects were not completed if (1) OHV activity 

was observed on the transect or (2) high wind speeds and lifting sand obstructed surveyors’ 

ability to detect the lizard. 

Two surveyors tapped the ground with 2.5m bamboo sticks in front of them while surveying 

in order to flush lizards. Microhabitat data was collected in addition to lizard numbers; this 

data included type of cover used, type of escape cover used, surface temperature, physical 

habitat (bowl, slip-face, dune ridge, sandy flat), habitat (active dune, psammophytic scrub), 

aspect, age (adult, sub-adult, hatchling), substrate the lizard was on, slope (degrees), and 

species. Approximately 99% of lizards observed were Uma notata. Results from these 

surveys are currently being analyzed. 

A similar monitoring protocol will be implemented following plan completion. In addition to 

applying this protocol to the wilderness area and the open area immediately south of 

Highway 78, monitoring transects will also be established in the Adaptive Management Area 

and in the open area south of the Adaptive Management Area. Fewer transects per area will 

be read than the number read in 2001, since preliminary analysis of the 2001 data indicate 

that sufficient precision can be obtained with a lower number of transects. For those areas 

sampled in 2001, a subset of the transects run in 2001 will be selected according to a random 

design (i.e., either simple random sampling, systematic random sampling, or restricted 

random sampling) for future measurement. For those areas not yet sampled, the WESTEC 

grid will again be used as described above, with transects positioned using a random design.

Sampling Objective: Sampling will be designed to achieve yearly estimates of lizard 

density that are within 30% of the true lizard density at the 95% confidence level within each 

of the 4 sampling areas. This sampling objective may be modified based on pilot sampling.

Analysis: Lizard densities in each of the five sampled areas will be compared over time to 

determine if there is a trend in density over time. The densities for each of the four areas 

may also be compared to determine if there are significant differences in density between 

areas, but this difference will be difficult to interpret given the variability in topography and 

probably climate throughout the entire dune system. It may be possible to use a multivariate 

repeated measures analysis of variance, as described under the analysis section for special 

status plants, to see if the responses of the lizards in each of the areas are parallel over time. 

The power of this analysis, however, depends upon the degree of correlation between years 

of each of the sampling units (belt transects). It is quite possible that this correlation will 

prove to be low with an organism this mobile, but pilot sampling should provide an answer.
19

Once more than 10 years of data are available, the parallel response hypothesis, even for 

independent samples, can be tested through regression analysis, treating density as the 

dependent variable and year as the independent variable.

FLAT-TAILED HORNED LIZARD

There have been approximately 20 sightings of the flat-tailed horned lizard (FTHL) in the 

Algodones Dunes, some well out in the dune interior. Foreman (1997) summarized existing 

information on FTHL habitat, concluding, “Flat-tailed horned lizards are probably rare in the 

unvegetated portions of major dune systems, such as the Algodones Dunes and the dunes of 

the Gran Desierto. (Luckenbach and Bury 1983, McCalvin 1993). However, much of the 

ISDRA is vegetated. Large areas of psammophytic scrub occur in the ISDRA. The only 

known surveys directed specifically toward the FTHL were conducted by BLM. These 

surveys looked at portions of the dunes near their perimeter (i.e., near roads) and consisted of 

2.5 mile long belt transects that were 50 inches wide (Wright 2002). During the 77 hours 

spent walking these transects, two lizards were sighted (a rate of 0.026 lizards/hour). This 

sighting rate of 0.026 lizards/hour is much lower than sighting rates for other areas in 

California. West Mesa, for example, an area known to provide good habitat for the species, 

has a sighting rate of about 0.2 lizards/hour, while the California range as a whole is about 

0.1 lizards/hour. These data appear to indicate that the FTHL is less abundant in the dunes, 

but the fact remains that the majority of the dunes have not been surveyed for the species.

The monitoring planned here is to search for FTHL on a randomly selected subset of the belt 

transects used for the Colorado Desert fringe-toed lizard. The FTHL will not be surveyed 

during the same time as the fringe-toed lizard transects because the FTHL will require 

considerably more time to read and because the FTHL must be surveyed following a wind 

event that erases previous lizard tracks (see below), a constraint not shared by the fringe-toed 

lizard monitoring.

Belt transects 724m (0.45 mile) long by 10m wide will be surveyed by teams of 2-

3 observers. Observers will carefully walk the transects looking for either lizards or lizard 

tracks. If tracks are found, they will be followed in an attempt to find the lizard. If found the 

lizard will be counted as being in the belt transect. The parameter estimate will be the 

number of lizards detected per hour of survey. A separate estimate of this parameter will be 

obtained for each of the areas surveyed (Mammoth Wash, wilderness area, open area north of 

the Adaptive Management Area, Adaptive Management Area, open area south of the 

Adaptive Management Area). 

Sampling Objective: No sampling objective is planned at this time. Studies in non-dune 

habitat (Wright 2002) have shown that detection rates of this cryptic animal can be very low 

and variable, leading to rather imprecise estimates of detection rate. The dune substrate 

allows observers to use tracks to locate lizards (something they were unable to do on other 

substrates), and this may result in lower coefficients of variation and more precise estimates 

of detection rate. On the other hand, the possible lower abundance of the lizard in the dunes 

may result in many zero values, leading to less precise estimates. Because of these 
20

unknowns, there is no reasonable means of estimating the potential coefficient of variation 

for FTHL data. Therefore, no sampling objectives will be set until pilot sampling yields an 

estimate of detection rate and its standard deviation.

Analysis: Analysis of FTHL detection rates will be conducted in a manner similar to that 

discussed above for Colorado Desert fringe-toed lizard density. Because FTHL estimates 

may not be very precise it may not be possible to detect other than drastic changes in FTHL 

abundance, but the monitoring will at least answer questions concerning whether 

psammophytic scrub supports many FTHL and, if so, what the FTHL distribution in the 

dunes is.

OHV USE

OHV use will be estimated by means of aerial photography. Sixteen air photo transects were 

established throughout the dunes in 1998 in order to obtain a sample of the distribution and 

intensity of OHV use in the dunes through the measurement of vehicle tracks. The aerial 

photographs obtained from these transects are at a 1:7000 scale, allowing the detection of 

vehicle tracks. These transects were flown on Easter weekend 1998 and reflown on Easter 

weekends in 1999, 2000, and 2001 (because of the ephemeral nature of vehicle tracks in 

sand, it was necessary to take the photographs during a weekend of relatively high vehicle 

use). The location of these air photo transects is shown in Willoughby (2000), along with the 

results of vehicle track frequency measurements for 1998. 

During the first four years of RAMP implementation, aerial photography will be obtained for 

the entire ISDRA during three heavy-use weekends (Thanksgiving, Presidents’ Day, and 

Easter) in one of these years and during one heavy-use weekend every year thereafter. The 

data from the three heavy-use weekends will be used to determine the timing of the yearly 

aerial photography. 

Aerial photographs will be sampled by means of a grid of points to estimate the cover of 

vehicle tracks in the dunes. The size of the grid and number of points per transect will be 

determined based on pilot sampling to meet the sampling objective described below. Future 

aerial photographs will be registered so that sampling grids can be placed in the same area in 

each year. 

Sampling Objec tive: Sampling will be designed to achieve yearly estimates of OHV track 

cover that are within 30% (relative) of the true OHV track cover at the 95% confidence level 

within each of the 9 management sampling areas. It is unlikely this objective can be met for 

the wilderness area since the OHV track cover there will likely be extremely low. This 

sampling objective may be modified based on pilot sampling. 

See the section for Peirson’s milk-vetch for more information on how these estimates of 

OHV use will be used to make inferences concerning the effects of different levels of OHV 

use on particular species.
21

VISITOR USE

In order to obtain better estimates of visitor use on holiday weekends, the following threepart monitoring study is planned:

- Personnel will collect the following data at major dune entry points: types of vehicles 

entering the dunes, number of people in vehicles, and the types of OHV vehicles they 

are bringing into the dunes.

- Electronic vehicle counters will be used to count vehicles coming into the dunes. 

Local regressions on the data collected in Part 1 will be used to extrapolate the 

estimated population and the type and number of vehicles.

- Conduct demographic studies to obtain data on the willingness-to-pay and actual 

expenditure data by OHV recreation visitors under different adaptive management 

regimes. These elements respond to the need to account for the economic impact of 

OHV recreation visitors to communities.

WEATHER STATIONS 

Long-term weather stations in the region do not completely capture the actual growing 

season precipitation occurring in the dunes. These weather stations are some distance from 

the dunes, the seasonal precipitation totals vary greatly between stations, and there is strong 

indication that precipitation varies considerably within the dunes during the same growing 

season (Willoughby 2000 and 2001). For these reasons, two Remote Area Weather Stations 

were set up in the dunes in fall 2000, one at the Cahuilla Ranger Station in the northwest part 

of the dunes and one at Buttercup Campground in the southern part of the dunes. These 

stations began collecting weather data on November 16, 2000. The Buttercup Station 

recorded significantly higher precipitation than the Cahuilla Station between November 2000 

and December 2001. Because of this variability and the importance of precipitation in 

controlling the abundance of special status plants, the Colorado Desert fringe-toed lizard, and 

the flat-tailed horned lizard, more weather stations are necessary to enable good 

interpretation of the monitoring data collected. If adequate funding is secured, five 

additional remote area weather station facilities will be installed in the dunes. These new 

stations will be located approximately as follows: (1) in the extreme northern part of the 

dunes in the vicinity of Mammoth Wash; (2) at the wildlife viewing area just northwest of 

Glamis; (3) along the Wash Road west of the junction of Ted Kipf and Vista Mine roads; (4) 

along the Wash Road west of Cactus; and (5) along the sand highway west of Tube 1.

Precipitation data gathered by the remote area weather stations will be compared to the 

results of monitoring to assist in determining whether a detected increase in the population of 

a special status species can be solely attributable to precipitation variability. This evaluation 

will assist in determining what, it any, management action is required in response to a 

detected change in population size. 
22

Additional Funding Required to Support Monitoring

Additional funding will be required to accomplish the monitoring described above. This 

funding includes both one-time and yearly costs, as detailed below. Also see the 

monitoring/study implementation schedule and costs for special status plant monitoring, 

included in the section on Peirson’s milk-vetch monitoring.

Need One-time Cost Yearly Cost

Personnel (monitoring, analysis, and GIS 

support) $250,000

Vehicle maintenance 5,000

Remote Area Weather Stations (5 @ 

$25,000 each) 125,000

Weather Station Maintenance 5,000

Aerial Photography and analysis costs in 

first 4 years of plan implementation $186,000

Aerial Photography and analysis yearly 

after first 4 years of plan implementation

62,000

Total 311,000 322,000

Personnel: Monitoring will be accomplished using a combination of full-time employees, 

seasonal employees, contractors, and volunteers. In addition to actually reading transects, 

two employees will provide logistical and safety support during monitoring periods (e.g., 

waiting at the end of transects with a vehicle, monitoring radio and telephone transmissions 

from monitors, etc.).

Remote Area Weather Stations: The need for these is discussed under the section on 

weather stations, above.

Aerial Photography: Sixteen air photo transects are currently being flown each year. The 

planned monitoring calls for complete coverage of the ISDRA during three heavy-use 

weekends (Thanksgiving, Presidents’ Day, and Easter) in one of the first four years, and once 

every year thereafter. The exact location of each aerial photograph will be registered and 

incorporated into a GIS.

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Colorado Cooperative Fish and Wildlife Research Unit, Fort Collins, CO.

Anderson, D. R., K. P. Burnham, B. C. Lubow, L. Thomas, P. S. Corn, P. A. Medica, and

 R.W. Marlow. 2001. Field trials of line transect methods applied to estimation of desert

 tortoise abundance. Journal of Wildlife Management 65:583-597.\
23

Barneby, R. C. 1964. Atlas of North American Astragalus. Memoirs of the New York 

Botanical Garden 13:953-954.

Elzinga, C. L., D. W. Salzer, and J. W. Willoughby. 1998. Measuring and monitoring plant 

populations. Technical Reference 1730-1, Bureau of Land Management, Denver, CO.

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animal populations. Blackwell Science, Malden, MA.

Foreman, L. D., ed. 1997. Flat-tailed horned lizard rangewide management strategy. 

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Holechek, J. L. 1988. An approach for setting the stocking rate. Rangelands 10:10-13.

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intercept method. Biometrika 64:618-622.

Luckenbach, R. A., and R. B. Bury. 1983. Effects of off-road vehicles on the biota of the 

Algodones Dunes, Imperial County, California. J. Applied Ecology 20:265-286.

McCalvin, C. 1993. Surveys for seven rare plant species, the flat-tailed horned lizard, and 

the Colorado Desert fringe-toed lizard. Report to Bureau of Reclamation, Boulder City, NV.

Pavlik, B.M. 1979. The biology of endemic psammophytes, Eureka Valley, California, and

 its relation to off-road vehicle impact. U.S. Bureau of Land Management, California Desert

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APPENDIX C

Appendix C summarizes the methodologies used to conduct the criteria pollutant air quality 

impact analysis to support the Draft EIS for the ISDRA. This appendix describes criteria 

pollutant emission estimation data and assumptions used in the analysis.

Emission Calculation Methodology

 

As discussed in Section 4.11 of the Draft EIS, Air Quality, this impact analysis involved 

separate evaluations of criteria pollutant emission analysis for the following six scenarios: 

- Existing Conditions – Year 1999 - 2000 

- Future Baseline – Year 2012 – 2013 

- Alternative 1 – Year 2012 – 2013 

- Alternative 2 – Year 2012 – 2013 

- Alternative 3 – Year 2012 – 2013 

- Alternative 4 – Year 2012 – 2013 

Emission inventories were developed for On-road Vehicle emission sources (automobile and 

recreational vehicles), and for Off Highway Vehicle (OHV)-related emission sources 

(motorcycle and other all-terrain vehicles).

Developing the emission inventories involved considerable data collection, to accurately 

reflect the existing and proposed levels of activity at the project site and the specific emission 

sources that would be involved. 

Specific information used to calculate emissions included: 

- Number and type of vehicle (quantity)

- Vehicle usage rates (hours per day)

- Number of annual and peak weekend visitors onsite

- Average speed of all vehicles

- Vehicle miles traveled (VMT) by vehicle type 

The number of vehicles was estimated based on visitor activities for the ISDRA, as shown in 

Section 2. The most current motor vehicle emission factors were derived from the California 

Air Resources Board (ARB) Motor Vehicle Emission Inventory (MVEI) models EMFAC7G 

and BURDEN 7G (http://www.arb.ca.gov/msei/mvei/mvdocs.htm). OHV emission factors 

were derived from information available in the U.S. EPA’s 1991 Non-road Engine and 

Vehicle Emission Study, U.S. EPA emission factors from AP-42, Compilation of Air 

Pollutant Emission Factors, as well as emission factors included in SCAQMD CEQA Air 

Quality Handbook (1993). Total emissions in terms of tons per year and pounds per day that 

would be generated during the calendar year and peak daily weekend periods were 

quantified.
Fugitive dust sources include paved and unpaved road-entrained dust. Emissions from these 

sources were quantified using emissions factors from the Compilation of Air Pollutant 

Emission Factors (AP-42), SCAQMD CEQA Air Quality Handbook and available 

documentation addressing fugitive dust. Detailed emission calculation spreadsheets and 

estimated total construction emissions are provided below

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NOTE: Links are on the next page. To open each section, click on the text of each line.

ALSO NOTE: Clicking on one of these links will open a non-PDF Web page. Watch for "Tabs" at

the bottom of some of these pages - click on the tab to reach that section of the document.
Emissions Factors for Alternative 1

Emissions Factors for Alternative 2

Emissions Factors for Alternative 3

Emissions Factors for Alternative 4

Estimated Future Emissions

Emissions Summary