Regional Mitigation

Strategy for the

Dry Lake Solar

Energy Zone

Technical Note 444

Produced by:

Bureau of Land Management

March 2014
Suggested citation:

Bureau of Land Management. 2014. Solar Regional Mitigation Strategy for the Dry Lake Solar Energy 

 Zone. Tech Note 444. Bureau of Land Management, Southern Nevada District Office, Las Vegas, NV.

Production services provided by:

Bureau of Land Management

National Operations Center

Information and Publishing Services Section

P.O. Box 25047

Denver, CO 80225

BLM/OC/ST-14/002+1794
Regional Mitigation

Strategy for the

Dry Lake Solar

Energy Zone

Produced by:

Bureau of Land Management

March 2014
ii • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

ACKNOWLEDGMENTS

his technical note is the 

product of a collaborative 

effort. Many people 

representing many 

different entities had a hand in its 

development. The project occurred 

under the leadership of Ray Brady, 

Bureau of Land Management 

(BLM) Washington Office. The final 

content was approved by the BLM 

Regional Mitigation Project Team: 

Joe Vieira (Lead), Michael Dwyer, 

Wendy Seley, and Gordon Toevs. 

Special thanks go to the Argonne 

National Laboratory project 

support team: Heidi Hartmann 

(Lead), Laura Fox, David Murphy, 

Karen Smith, Shannon Stewart, 

Konstance Wescott, and Lee 

Walston. Special thanks also go to 

John McCarty (BLM Washington 

Office), Rochelle Francisco 

(BLM Nevada State Office), Fred 

Edwards, Mark Slaughter, Kathleen 

Sprowl, Boris Poff, and the other 

members of the BLM Southern 

Nevada District, Pahrump Field 

Office Interdisciplinary Team. 

Members of the Information and 

Publishing Services Section at the 

BLM National Operations Center 

assisted by providing editorial and 

design and layout services. Many 

others contributed by attending 

or helping conduct one or more of 

the workshops conducted to obtain 

input from interested parties, by 

providing comments on draft 

versions of this document, and by 

providing management oversight 

and/or technical support. Thanks to 

all who contributed! 

T
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • iii

TABLE OF CONTENTS

ABSTRACT___________________________________________________________________________________ 1

1. INTRODUCTION AND PURPOSE ______________________________________________________________ 2

1.1 Purpose of the Strategy ______________________________________________________________________ 2

1.2 Background _____________________________________________________________________________ 3

1.3 Solar Regional Mitigation Strategy Process __________________________________________________________ 4

1.4 Stakeholder Involvement in the Solar Regional Mitigation Strategy Process _______________________________________ 5

2. MITIGATION STRATEGY – DRY LAKE SOLAR ENERGY ZONE _________________________________________ 6

2.1 Description of the Dry Lake Solar Energy Zone and Surrounding Region _________________________________________ 6

2.1.1 General Description of the Solar Energy Zone _____________________________________________________ 6

2.1.2 Landscape Conditions of the Solar Energy Zone and the Region __________________________________________ 6

2.1.3 Regional Setting ______________________________________________________________________ 8

2.1.3.1 General Description _______________________________________________________________ 8

2.1.3.2 Problematic Regional Trends __________________________________________________________ 8

2.2 General Description of Solar Development in the Dry Lake Solar Energy Zone _____________________________________ 18

2.2.1 Description of Existing Rights-of-Way and Impact on Developable Area ____________________________________ 18

2.2.2 Description of Potential Development ________________________________________________________ 18

2.3 Summary of Solar Development Impacts on the Dry Lake Solar Energy Zone _____________________________________ 19

2.4 Mitigation Strategy (Hierarchy) of the Dry Lake Solar Energy Zone____________________________________________ 20

2.4.1 Avoidance _________________________________________________________________________ 20

2.4.1.1 Dry Wash/Riparian Areas ___________________________________________________________ 20

2.4.1.2 Existing Rights-of-Way, Mining Claims, etc. ________________________________________________ 20

2.4.2 Minimization _______________________________________________________________________ 21

2.4.2.1 Summary of Programmatic Design Features to be Applied _______________________________________ 21

2.4.2.2 Other Required Impact Minimization Measures and/or Stipulations__________________________________ 21

2.4.3 Regional Mitigation ___________________________________________________________________ 21

2.4.3.1 Identification of Unavoidable Impacts ___________________________________________________ 22

2.4.3.2 Unavoidable Impacts that May Warrant Regional Mitigation ______________________________________ 23

2.4.3.2.1 Conceptual Models_________________________________________________________ 23

2.4.3.2.2 Unavoidable Impacts that May Warrant Regional Mitigation ________________________________ 23

2.5 Regional Mitigation Goals ___________________________________________________________________ 24

2.5.1 Background on Regional Goals_____________________________________________________________ 24

2.5.2 Las Vegas Resource Management Plan Goals and Objectives ___________________________________________ 24

2.5.3 Dry Lake Solar Energy Zone Mitigation Goals and Objectives ___________________________________________ 25

2.6 Calculating the Recommended Mitigation Fee for the Dry Lake Solar Energy Zone __________________________________ 26

2.7 Management of Solar Regional Mitigation Fees_______________________________________________________ 28

2.8 Evaluation of Mitigation Locations, Objectives, and Actions________________________________________________ 29

2.9 Mitigation Effectiveness Monitoring and Adaptive Management Plan _________________________________________ 35

2.10 Implementation Strategy ____________________________________________________________________ 43

REFERENCES ________________________________________________________________________________ 45

APPENDIX A: Impact Assessment Summary Table __________________________________________________________ 46

APPENDIX B: Regional and Dry Lake Solar Energy Zone Conceptual Models ___________________________________________ 51

APPENDIX C: Summary Table: Impacts that May Warrant Regional Mitigation for the Dry Lake Solar Energy Zone ____________________ 54

APPENDIX D: BLM Screening of Candidate Regional Mitigation Sites for the Dry Lake Solar Energy Zone _________________________ 57

APPENDIX E: Mitigation of Visual Resource Impacts in the Dry Lake Solar Energy Zone ____________________________________ 63
iv • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Figures

2-1 Dry Lake Solar Energy Zone and surrounding area _____________________________________________ 7

2-2 Landscape condition in the Mojave Basin and Range ecoregion __________________________________ 9

2-3 Landscape condition in the Dry Lake Solar Energy Zone ________________________________________ 10

2-4 Dry Lake Solar Energy Zone and surrounding land designations _________________________________ 11

2-5 Land cover types in the Mojave Basin and Range ecoregion_____________________________________ 12

2-6 Land cover types in the vicinity of the Dry Lake Solar Energy Zone _______________________________ 13

2-7 Conceptual diagram for estimating condition and trends of

conservation elements in the Mojave Basin and Range ecoregion

for the Dry Lake Solar Energy Zone Solar Regional Mitigation Strategy ____________________________ 15

2-8 Dry Lake Solar Energy Zone revised developable area__________________________________________ 20

2-9 Steps for calculating per-acre regional mitigation fees _________________________________________ 26

2-10 Gold Butte Area of Critical Environmental Concern ____________________________________________ 31

2-11 Example of a stratified, nonbiased sampling schema for the Dry Lake Solar Energy Zone _____________ 40

2-12 Example of a stratified, nonbiased sampling schema for the Gold Butte Area

of Critical Environmental Concern__________________________________________________________ 41

Tables

2-1 Ecological stressor source, site-impact scores, and distance decay scores implemented

for the landscape condition model for the Mojave Basin and Range _______________________________ 8

2-2 Land cover types and amounts in the vicinity of the Dry Lake Solar Energy Zone ____________________ 14

2-3 Condition and trends assessment for coarse and fine filter conservation elements

in the Mojave Basin and Range relevant to the Dry Lake Solar Energy Zone ________________________ 16

2-4 Estimate of funding needed for management activities to ensure effectiveness and durability_________ 27

2-5 Dry Lake Solar Energy Zone goals and objectives associated with mitigation

in the Gold Butte Area of Critical Environmental Concern _______________________________________ 32

2-6 Priority/order of Gold Butte Area of Critical Environmental Concern

mitigation goals and objectives____________________________________________________________ 34

2-7 Recommended methods and measurements for core and contingent indicators. ___________________ 37

2-8 Quantitative indicators and measurements relevant to each

of the three rangeland health attributes_____________________________________________________ 38
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 1

ABSTRACT

he “Regional Mitigation 

Strategy for the Dry 

Lake Solar Energy Zone” 

presents a strategy for 

compensating for the unavoidable 

impacts that are expected from 

the development of the Dry Lake 

Solar Energy Zone (SEZ) in southern 

Nevada. This strategy responds to 

a call for the development of solar 

regional mitigation strategies for 

each of the SEZs, as committed to 

in the record of decision for the 

“Final Programmatic Environmental 

Impact Statement (PEIS) for 

Solar Energy Development in 

Six Southwestern States.” The 

strategy consists of preliminary 

findings and recommendations 

for conducting each element of 

a process that identifies: (1) the 

unavoidable impacts of utilityscale solar development in the 

Dry Lake SEZ that may warrant 

regional mitigation; (2) mitigation 

actions that can be implemented 

in the region to compensate for 

those impacts; (3) how a regional 

mitigation fee could be calculated; 

and (4) how the impacts and 

mitigation actions could be 

monitored. While this pilot strategy 

for the Dry Lake SEZ is not a Bureau 

of Land Management decision, 

it will inform future decision 

documents for: configuration of 

lease parcels within the Dry Lake 

SEZ; lease stipulations; impacts to 

be mitigated in the region; where 

and how regional mitigation will 

occur; and how monitoring and 

adaptive management will occur.

T
2 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

T

1. INTRODUCTION AND PURPOSE 

1.1 Purpose of the Strategy

he “Regional Mitigation 

Strategy for the Dry 

Lake Solar Energy Zone” 

recommends a strategy 

for compensating for certain 

unavoidable impacts that are 

expected from the development 

of the Dry Lake Solar Energy Zone 

(SEZ) in southern Nevada. The 

Bureau of Land Management (BLM) 

is required to manage the public 

lands in a manner that will protect 

the quality of ecological and 

environmental values and provide 

for wildlife habitat in a way that 

does not result in the permanent 

impairment of the productivity of 

the land. While the BLM places a 

priority on mitigating impacts to 

an acceptable level onsite, there 

are times when onsite mitigation 

alone may not be sufficient. In these 

cases, which are likely to occur with 

utility-scale solar development, 

which often involves a long-term 

commitment of resources over 

a relatively large area, the BLM 

is considering requirements for 

regional mitigation for those 

unavoidable impacts that could 

exacerbate problematic regional 

trends. Accordingly, this pilot 

strategy articulates:

1. The unavoidable impacts 

expected as a result of 

development of the Dry Lake 

SEZ.

2. The problematic trends in the 

Mojave Desert, where the Dry 

Lake SEZ is located.

3. A conceptual model that 

depicts the relationships 

between resources, ecosystem 

functions, ecosystem services, 

and change agents (including 

development, climate change, 

wildfire, etc.).

4. The unavoidable impacts that, 

in consideration of regional 

trends and roles the impacted 

resources play, may warrant 

regional mitigation.

5. The regional mitigation goals 

and objectives recommended 

for the Dry Lake SEZ.

6. The regional mitigation 

locations and action(s) 

recommended for achieving the 

mitigation goals and objectives 

for the Dry Lake SEZ.

7. The estimated cost of the 

mitigation action(s), including 

a breakout of acquisition, 

restoration, and/or ongoing 

management costs to ensure 

effectiveness and durability.

8. A recommended method for 

calculating a mitigation fee that 

could be assessed to developers 

and an explanation of how it 

was calculated for the Dry Lake 

SEZ.

9. A recommendation for how the 

BLM fee revenue derived from 

development of the Dry Lake 

SEZ could be managed.

10. A recommendation for how 

the outcomes of the mitigation 

actions could be monitored and 

what will happen if the actions 

are not achieving the desired 

results.

This pilot strategy will guide 

future decisions for:

•	 The configuration of lease

parcels within the Dry Lake SEZ. 

•	 The lease stipulations to achieve

avoidance and minimization of 

impacts.

•	 The impacts to be mitigated in

the immediate region.

•	 Where and how regional

mitigation will occur.

•	 Monitoring and adaptive

management.

•	 Developing BLM policy to guide

regional mitigation.

The BLM authorized officer 

will make these decisions prior 

to leasing and will also take into 

consideration:

•	 The National Environmental

Policy Act (NEPA) analysis 

done for the proposed action, 

including comments submitted 

by the public and other 

stakeholders.

•	 Any changes to the applicable

resource management plan 

(RMP) or other plans that affect 

management of the SEZ or 

possible mitigation sites. 

•	 The input received from

consultation with tribes. 

•	 Any other information that

would update, correct, or 

otherwise supplement the 

information contained in this 

strategy.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 3

1.2 Background

n 2012, the BLM and the 

U.S. Department of Energy 

published the “Final 

Programmatic Environmental 

Impact Statement (PEIS) for 

Solar Energy Development in Six 

Southwestern States” (Final Solar 

PEIS). The Final Solar PEIS assessed 

the impact of utility-scale solar 

energy development on public 

lands in the six southwestern 

states of Arizona, California, 

Colorado, Nevada, New Mexico, 

and Utah. The “Approved Resource 

Management Plan Amendments/

Record of Decision (ROD) for 

Solar Energy Development 

in Six Southwestern States” 

(Solar PEIS ROD) implemented 

a comprehensive solar energy 

program for public lands in those 

states and incorporated land use 

allocations and programmatic 

and SEZ-specific design features 

into land use plans in the six-state 

study area (BLM 2012). The Solar 

PEIS ROD identified 17 priority 

areas for utility-scale solar energy 

development, or SEZs. The Final 

Solar PEIS presents a detailed 

analysis of the expected impacts of 

solar development on each SEZ. 

Comments on both the Draft 

Solar PEIS and the Supplement to 

the Draft Solar PEIS encouraged 

the BLM to incorporate a 

robust mitigation framework 

into the proposed solar energy 

program to address unavoidable 

impacts expected in SEZs. In the 

Supplement to the Draft Solar PEIS, 

the BLM presented, as part of its 

incentives for SEZs, the concept 

of regional mitigation planning1. 

A draft framework for regional 

mitigation planning was posted on 

the project web page between the 

1

 In the Final Solar Energy PEIS (BLM and DOE 2012), Appendix 

A, Section A.2.5, the BLM refers to solar regional mitigation plans 

(SRMPs). To be consistent with guidance issued in BLM Instruction 

Memorandum 2013-142 (BLM 2013b), the BLM adopts the terminology of solar regional mitigation strategies (SRMSs).

publication of the Supplement to 

the Draft Solar PEIS and the Final 

Solar PEIS to foster stakeholder 

engagement. A framework for 

regional mitigation planning was 

included in the Final Solar PEIS and 

the Solar PEIS ROD. Concurrent with 

the development of this strategy, 

the BLM has developed a technical 

reference, titled “Procedural 

Guidance for Developing Solar 

Regional Mitigation Strategies,” to 

provide guidance on the process 

and a refined framework to aid in 

the preparation of solar regional 

mitigation strategies (SRMSs) for 

other SEZs (BLM forthcoming). 

The BLM’s policy is to mitigate 

impacts to an acceptable level 

onsite whenever possible 

through avoidance, minimization, 

remediation, or reduction of 

impacts over time. The use of 

regional mitigation is evaluated 

by the BLM on a case-by-case 

basis and is based on the need 

to address resource issues that 

cannot be acceptably mitigated 

onsite. Furthermore, not all 

adverse impacts can or must be 

fully mitigated either onsite or in 

the immediate region. A certain 

level of adverse or unavoidable 

impact may be acceptable: (1) 

when an appropriate level of 

mitigation will be conducted and 

remaining impacts do not result in 

unnecessary or undue degradation; 

or (2) when impacts to BLM 

sensitive species or Endangered 

Species Act-listed species do not 

exceed established resource and 

value objectives. 

In order to minimize the 

impacts of solar development, 

the BLM applies a mitigation 

hierarchy, consisting of avoid, 

minimize, and compensate. 

Implementation of this hierarchy 

begins with the location and 

configuration of the SEZs, so as 

to avoid as many conflicts as 

possible. Avoidance is also used 

within the boundaries of SEZs 

by designating nondevelopable 

areas. Minimization involves the 

implementation of design features 

(which are required mitigation 

measures) and management 

practices meant to reduce the 

impacts onsite. As a part of the 

analysis, the Final Solar PEIS 

included a robust suite of design 

features in the BLM’s solar energy 

program that will be employed to 

minimize some of the expected 

impacts of development onsite. 

The Final Solar PEIS analyzed, 

and the Solar PEIS ROD adopted, 

both programmatic and SEZspecific design features. These 

design features will be included as 

stipulations in right-of-way leases 

for SEZs. 

This SRMS addresses the final 

tier of the mitigation hierarchy, 

specifically compensatory 

mitigation, hereafter referred 

to as regional mitigation. 

This pilot strategy consists of 

recommendations to mitigate 

some of the unavoidable impacts 

that remain after avoidance 

and minimization measures are 

taken. This strategy differs from 

project-level compensatory 

mitigation planning that has been 

conducted in the past. In this 

pilot, compensatory mitigation is 

considered in a landscape context 

and includes identification of 

mitigation goals and objectives, as 

well as the selection of mitigation 

actions based on the degree of 

impact and regional conditions 

and trends. This procedure for 

conducting mitigation is also 

reflected in the BLM’s interim 

policy, Draft Manual Section 1794, 

“Regional Mitigation,” issued on 

June 13, 2013.

I
4 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

1.3 Solar Regional Mitigation

Strategy Process

n August 2012, the BLM 

initiated the pilot Dry 

Lake SEZ Solar Regional 

Mitigation Planning Project, 

which constitutes the first SRMS 

developed for an SEZ. The Dry 

Lake SEZ SRMS originated 

simultaneously with, and served 

as a pilot test case for, the 

establishment of BLM guidance 

for developing SRMSs for other 

SEZs (BLM forthcoming). The effort 

was conducted with a significant 

amount of public involvement, 

including four workshops, 

several web-based meetings, and 

opportunities to comment on 

preliminary and draft versions of 

methodologies and strategies. 

The Dry Lake SEZ is located 

about 15 mi (24 km) northeast of 

Las Vegas in Nevada. The process 

for developing the Dry Lake SEZ 

SRMS largely followed the outline 

for regional mitigation planning 

outlined in the Final Solar PEIS. In 

general, a team of specialists from 

the BLM Southern Nevada District 

Office, with the support of Argonne 

National Laboratory, produced a 

preliminary product at each step 

in the process, which was then 

presented and discussed in a public 

forum. The opportunity for written 

comments was also extended to the 

public. The content and methods 

used in this process incorporate 

many of the ideas and comments 

received from the public.

The mitigation actions 

identified in this strategy are 

designed to compensate for 

the loss of some of the habitat, 

visual resources, and ecological 

services that are expected from 

the development of the Dry 

Lake SEZ. For the purpose of this 

analysis, it is assumed that all of 

the developable land within the 

Dry Lake SEZ will be impacted. The 

degree of compensation will take 

into consideration the condition 

of the resource values present in 

the Dry Lake SEZ and also consider 

the relative costs and benefits of 

the use of public lands for solar 

energy development, including the 

amount of time and effort required 

to restore the disturbed area 

upon expiration of the lease. The 

recommended mitigation actions 

are drawn from the “Proposed Las 

Vegas Resource Management Plan 

and Final Environmental Impact 

Statement” (Las Vegas RMP) (BLM 

1998). They consist of restoration 

and preservation measures 

prescribed for the Gold Butte Area 

of Critical Environmental Concern 

(ACEC), but for which sufficient 

resources have been unavailable. 

The Gold Butte ACEC is in the same 

ecological zone (ecoregion) and 

subzone as the Dry Lake SEZ and is 

of the same vegetation community. 

The Gold Butte ACEC provides 

habitat for all of the wildlife, 

including the special status species, 

found in the Dry Lake SEZ.

Under the terms of this strategy, 

funding derived from mitigation 

fees for the Dry Lake SEZ will not 

be sufficient to fund all of the 

potential restoration and protection 

needs in the Gold Butte ACEC, but 

they will allow significant progress 

toward achieving the management 

objectives for the ACEC: to preserve 

the extraordinary resource values 

found there while providing for 

human use and enjoyment. As 

part of the proposed solar energy 

program, the solar long-term 

monitoring program will be used 

to evaluate the effectiveness of 

mitigation strategies employed 

through regional mitigation plans. 

Regional mitigation strategies will 

be subject to continued review 

and adjustment by the BLM and 

its partners to ensure conservation 

goals and objectives are being met. 

I
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 5

1.4 Stakeholder Involvement in the

Solar Regional Mitigation Strategy Process

he pilot process for 

including stakeholder 

input in developing the Dry 

Lake SEZ SRMS included 

four workshops in Las Vegas and 

several web-based meetings. 

Representatives from federal, state, 

and local government agencies; 

nongovernmental organizations 

concerned with issues such as 

environmental or recreational 

impacts; representatives from 

the solar development industry, 

mining industry, and utilities; tribal 

representatives; and individual 

members of the public who had 

been involved in the Solar PEIS 

process were invited to attend 

these activities. Approximately 70 

individuals and representatives 

from the previously mentioned 

organizations attended the kickoff 

workshop held August 29-30, 

2012. During the first workshop, 

background on regional mitigation 

planning and the Solar PEIS impact 

assessment for the Dry Lake SEZ 

were provided to the attendees. 

The subsequent three workshops all 

had about 35 attendees, including 

individuals and representatives 

from agencies, nongovernmental 

organizations, the solar industry 

and consultants to the industry, 

utilities, and tribes. 

The second workshop was held 

October 24-25, 2012. This workshop 

included a field visit to the Dry Lake 

SEZ in order to give the participants 

a firsthand look at the SEZ. BLM 

staff experts were present and 

spoke about the range of resources 

present in the SEZ and possible 

opportunities available to avoid, 

minimize, and mitigate potential 

impacts related to solar energy 

development.

The third workshop was 

held January 30-31, 2013. This 

workshop focused on regional 

trends and conditions, unavoidable 

impacts that may warrant regional 

mitigation, the establishment of 

regional mitigation objectives, the 

use of mapping tools and data in 

choosing locations for mitigation, 

prioritization of mitigation projects, 

mitigation costing, and long-term 

monitoring. 

The fourth workshop, held 

on February 27, 2013, focused 

on three topics: (1) methods for 

establishing mitigation fees in SEZs, 

and specifically in the Dry Lake SEZ; 

(2) establishing solar mitigation 

objectives and priority setting; 

and (3) structures for holding and 

applying mitigation funds. 

Additionally, several webinars 

were held to provide information 

on: mitigation valuation methods 

and mitigation structure options 

(December 6, 2012); methods to 

identify impacts that may warrant 

mitigation (January 1, 2013); 

and a proposed mitigation fee 

setting method and method to 

evaluate candidate mitigation sites 

(March 21, 2013). 

All presentations from the four 

workshops and three webinars are 

posted on the project documents 

web page on the Dry Lake SEZ 

SRMS Project website at: http://

www.blm.gov/nv/st/en/fo/lvfo/

blm_programs/energy/dry_lake_

solar_energy.html. Reports from 

the workshops are also available. 

Additional materials that were 

provided for stakeholder review 

are posted on the project website 

documents page as well. 

Throughout the pilot project, 

stakeholders were invited to 

comment on interim draft 

materials, including the summary 

of unavoidable impacts at the 

Dry Lake SEZ that may warrant 

mitigation, the proposed method 

for deriving the mitigation fees, the 

method of evaluating candidate 

sites for mitigation, and the specific 

mitigation sites and activities 

proposed for the Dry Lake SEZ. 

Many of these comments were 

discussed during workshops and 

used to guide development of this 

strategy.

T
6 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

2.1 Description of the Dry Lake Solar

Energy Zone and Surrounding Region

2.1.1 General Description 

of the Solar Energy Zone

The Dry Lake SEZ is located in 

Clark County in southern Nevada. 

The total area of the Dry Lake SEZ, 

as shown in Figure 2-1, is 6,187 

acres (25 km2) (BLM and DOE 2012). 

In the Final Solar PEIS and the Solar 

PEIS ROD, 469 acres (1.9 km2) of 

floodplain and wetland within the 

SEZ boundaries were identified 

as nondevelopment areas. The 

developable area of the SEZ 

given in the Final Solar PEIS was 

5,717 acres (23 km2).

The towns of Moapa and 

Overton are located 18 mi (29 km) 

northeast and 23 mi (37 km) east 

of the SEZ, respectively. Nellis Air 

Force Base is located approximately 

13 mi (21 km) southwest of the SEZ. 

The nearest major roads accessing 

the proposed Dry Lake SEZ are 

Interstate 15, which passes along 

the southeastern boundary of the 

SEZ, and U.S. Route 93, which runs 

from north to south along part of 

the southwest border of the SEZ. 

The Union Pacific Railroad runs 

north to south along a portion of 

the eastern SEZ boundary, with 

the nearest stop in Las Vegas. The 

area around the SEZ is not highly 

populated, although Clark County, 

with a 2008 population close to 

2 million individuals, has a large 

number of residents. 

The SEZ already contains 

rights-of-way and developed 

areas, including energy, water, 

and transportation infrastructure 

facilities. Three designated 

transmission corridors pass 

through the area, including a 

Section 368 energy corridor (of 

the Energy Policy Act of 2005), 

which contains numerous electric 

transmission lines, natural gas and 

refined petroleum product lines, 

and water lines (see Figure 2-1 for 

the designated corridor). A power 

generating station is also located 

within the area of the SEZ, and two 

existing natural gas power plants 

are located just southwest of the 

SEZ on private land. A minerals 

processing plant is located in the 

southeastern corner of the SEZ. 

The Final Solar PEIS indicated that 

in 2012 there were three pending 

solar applications within or adjacent 

to the SEZ and an additional large 

application area located about 2 mi 

(3 km) to the east of the SEZ across 

Interstate 15. 

2.1.2 Landscape 

Conditions of the

Solar Energy Zone

and the Region

In 2012, the BLM completed 

the “Mojave Basin and Range Rapid 

Ecoregional Assessment” for the 

Mojave Basin and Range ecoregion 

in which the Dry Lake SEZ is located 

(NatureServe 2013). The Mojave 

Basin and Range REA examines 

broad-scale ecological values, 

conditions, and trends within the 

ecoregion by synthesizing existing 

spatial datasets in a meaningful 

timeframe. The REAs serve multiple 

purposes in an ecoregional 

context, including identifying and 

answering important management 

questions; understanding key 

resource values; understanding 

the influence of various change 

agents; understanding projected 

ecological trends; identifying and 

mapping key opportunities for 

resource conservation, restoration, 

and development; and providing 

a baseline to evaluate and guide 

future actions.

One useful product of the 

REAs is the development of 

landscape condition models. 

These geospatial models have 

been created to represent the 

condition or level of intactness 

throughout the ecoregion at the 

time in which the assessments were 

initiated (approximately 2010). 

The landscape condition model 

is a combination of two primary 

factors—land use and a distance 

decay function from land uses. 

Different land use categories were 

assigned a relative value between 

0 and 1, representing very high 

landscape alteration to very little 

landscape alteration. For example, 

high-density urban areas received 

values closer to 0, whereas intact 

undisturbed areas received values 

closer to 1. The distance decay 

function considered the proximity 

of each location to human land 

uses. Table 2-1 lists a number of 

examples of land use and distance 

decay scores for various stressor 

categories in the Mojave Basin and 

2. MITIGATION STRATEGY –

DRY LAKE SOLAR ENERGY ZONE
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 7

Range. A full description of the 

landscape condition model and 

how it was developed can be found 

in the “Mojave Basin and Range 

Rapid Ecoregional Assessments 

Final Memorandum I-3-C.”

The landscape condition 

model developed for the Mojave 

Basin and Range was developed 

as a raster dataset of 100-m cells. 

The model illustrates landscape 

condition values throughout the 

ecoregion (Figure 2-2). The resulting 

map provides a composite view of 

the relative impacts of land uses 

across the entire ecoregion. Darker 

green areas indicate apparently 

least impacted areas (most intact) 

and orange-red areas are the most 

impacted (least intact). According 

to this landscape condition model, 

most of the impacts occur near 

urban areas (e.g., Las Vegas) and 

along roadways. However, most 

of the Mojave Basin and Range is 

still relatively intact. The landscape 

condition within the Dry Lake SEZ is 

shown in Figure 2-3. 

Figure 2-1. Dry Lake Solar Energy Zone and surrounding area (Source: BLM and DOE 2012).
8 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

2.1.3 Regional Setting

2.1.3.1 General Description

The Dry Lake SEZ is situated 

within 5 mi (8 km) of several other 

federally owned or administered 

lands. The Moapa River Indian 

Reservation is approximately 4 mi 

(6.4 km) northeast of the revised 

SEZ boundary. The Coyote Springs 

ACEC, which is also designated 

critical habitat for the federally 

threatened desert tortoise, is 

located within 0.5 mi (0.8 km) west 

of the SEZ. Farther west of the 

Coyote Springs ACEC is the U.S. 

Fish and Wildlife Service Desert 

National Wildlife Refuge, which is 

approximately 3 mi (4.8 km) west 

of the SEZ. The Muddy Mountains 

Wilderness Area is approximately 

8 mi (12.9 km) southeast of the SEZ 

(Figure 2-4).

The Dry Lake SEZ is located 

in a relatively undeveloped rural 

area, bounded on the west by the 

Arrow Canyon Range and on the 

southeast by the Dry Lake Range. 

The topography of the land within 

the SEZ is arid basin dominated 

by creosote and white bursage 

vegetation communities. Land 

cover types2 within the ecoregion 

are presented in Figure 2-5. At a 

more local scale, land cover types in 

the vicinity of the Dry Lake SEZ are 

shown in Figure 2-6. In total, there 

are 10 natural land cover types 

and 2 disturbance land cover types 

predicted to occur in the vicinity 

(i.e., within 5 mi, or 8 km) of the 

Dry Lake SEZ (Table 2-2). There are 

three land cover types that occur 

in the developable portion of the 

SEZ (Table 2-2). Listed in order of 

dominance, these land cover types 

are: Sonora-Mojave Creosote-White 

Bursage Desert Scrub (98.8% of the 

developable area), Sonora-Mojave 

2

 Geospatial data for land cover types were obtained from the 

Southwest Regional Gap Analysis Project (http://earth.gis.usu.edu/

swgap/) and the California Gap land cover mapping project (http://

gap.uidaho.edu/index.php/california-land-cover/). 

2.1.3.2 Problematic Regional Trends

The Mojave Basin and Range 

REA presents a framework for 

determining the condition and 

trend of various resource values 

and conservation elements in the 

ecoregion. The Mojave Basin and 

Mixed Salt Desert Scrub (0.8% of 

the developable area), and North 

American Warm Desert Wash (0.4% 

of the developable area). Other land 

cover types expected to occur in 

the nondevelopable area of the SEZ 

include Developed, Medium – High 

Intensity and North American Warm 

Desert Pavement (Table 2-2).

Table 2-1. Ecological stressor source, site-impact scores, and distance decay scores implemented for 

the landscape condition model for the Mojave Basin and Range.

Range REA defines conservation 

elements as resources of 

conservation concern within an 

ecoregion. These elements could 

include habitat or populations 

for plant and animal taxa, such 

as threatened and endangered 

species, or ecological systems and 

Ecological Stressor Source

Site 

Impact 

Score

Presumed 

Relative 

Stress

Distance 

Decay 

Score

Impact 

Approaches 

Negligible

Transportation

Dirt roads, 4-wheel drive 0.7 Low 0.5 200 m

Local, neighborhood and connecting roads 0.5 Medium 0.5 200 m

Secondary and connecting roads 0.2 High 0.2 500 m

Primary highways with limited access 0.05 Very High 0.1 1,000 m

Primary highways without limited access 0.05 Very High 0.05 2,000 m

Urban and Industrial Development

Low-density development 0.6 Medium 0.5 200 m

Medium-density development 0.5 Medium 0.5 200 m

Powerline/transmission lines 0.5 Medium 0.9 100 m

Oil/gas wells 0.5 Medium 0.2 500 m

High-density development 0.05 Very High 0.05 2,000 m

Mines 0.05 Very High 0.2 500 m

Managed and Modified Land Cover

Ruderal forest and upland 0.9 Very Low 1 0 m

Native vegetation with introduced species 0.9 Very Low 1 0 m

Pasture 0.9 Very Low 0.9 100 m

Recently logged 0.9 Very Low 0.5 200 m

Managed tree plantations 0.8 Low 0.5 200 m

Introduced tree and shrub 0.5 Medium 0.5 200 m

Introduced upland grass and forb 0.5 Medium 0.5 200 m

Introduced wetland 0.3 High 0.8 125 m

Cultivated agriculture 0.3 High 0.5 200 m
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 9

plant communities of regional 

importance. A list of conservation 

elements could also include other 

resource values, such as highly 

erodible soils; populations of 

wild horses and burros; scenic 

viewsheds; or designated sites 

of natural, historical, or cultural 

significance. There are two basic 

types of conservation elements in 

the Mojave Basin and Range:

•	 Coarse filter conservation

elements, which typically include 

all of the major ecosystem types 

within the assessment landscape 

and represent all of the 

predominant natural ecosystem 

functions and services in the 

ecoregion.

•	 Fine filter conservation elements,

which complement the first 

set of elements by including a 

limited subset of focal species 

assemblages and individual 

species.

Figure 2-2. Landscape condition in the Mojave Basin and Range ecoregion. Darker green areas indicate least impacted areas (most intact),

whereas orange-red areas are the most impacted (least intact). Also shown is the 5-mile buffer around the Dry Lake Solar Energy Zone.
10 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Figure 2-3. Landscape condition in the Dry Lake Solar Energy Zone. Approximately 3,471 acres of the solar energy zone are considered eligible for

utility-scale solar energy development.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 11

Figure 2-4. Dry Lake Solar Energy Zone and surrounding land designations.
12 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Figure 2-5. Land cover types in the Mojave Basin and Range ecoregion.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 13

Figure 2-6. Land cover types in the vicinity of the Dry Lake Solar Energy Zone.
14 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Table 2-2. Land cover types and amounts in the vicinity of the Dry Lake Solar Energy Zone.

Description Acres Within SEZ 

Developable Area1

Acres Within Entire SEZ 

(Developable and

Nondevelopable)2

Acres Within 

5-Mile Buffer 

Around SEZ3

Natural Land Cover Types

Sonora-Mojave Creosotebush-White 

Bursage Desert Scrub 3,427 (98.8%) 5,879 (95.0%) 83,300 (84.1%)

Sonora-Mojave Mixed Salt Desert Scrub 30 (0.8%) 38 (0.6%) 645 (0.7%)

North American Warm Desert Wash 14 (0.4%) 141 (2.3%) 2,618 (2.6%)

North American Warm Desert 

Pavement 21 (0.3%) 1,694 (1.7%)

North American Warm Desert Bedrock 

Cliff and Outcrop 5,144 (5.2%)

Mojave Mid-Elevation Mixed

Desert Scrub 4,651 (4.7%)

North American Warm Desert Playa 287 (0.3%)

Inter-Mountain Basins Semi-Desert 

Shrub Steppe 147 (0.1%)

Open Water 1 (<0.1%)

North American Warm Desert Riparian 

Mesquite Bosque 1 (<0.1%)

Disturbance Land Cover Types

Developed, Medium - High Intensity 108 (1.8%) 495 (0.5%)

Invasive Southwest Riparian Woodland 

and Shrubland 11 (<0.1%)

TOTAL (acres): 3,471 6,187 98,994

1 Values in parentheses represent the percent acreage relative to the entire developable area 

(3,471 acres).

2

 Values in parentheses represent the percent acreage relative to the entire SEZ (6,187 acres).

3

 Values in parentheses represent the percent acreage relative to the entire 5-mile buffer area (98,994 acres).

A full list and explanation 

of the coarse filter conservation 

elements within the Mojave 

Basin and Range can be found in 

Appendix 2 of the Mojave Basin 

and Range REA. In brief, the core 

conservation elements include 19 

coarse filter conservation elements 

that represent terrestrial and 

aquatic ecological system types and 

communities and more than 600 

fine filter conservation elements 

that represent individual species or 

species assemblages.

Problematic trends are 

understood by forecasting the 

response of conservation elements 

to one of four change agents in 

the ecoregion. The four change 

agents include fire, invasive species, 

climate change, and human 

development. Of these change 

agents, the conservation element 

responses to human development 

are the easiest to predict in a 

meaningful timeframe for SRMSs 

because solar energy development 

represents an anthropogenic 

disturbance, and the impacts of 

human development are likely to 

affect all conservation elements 

similarly.

Understanding the problematic 

conservation element trends 

relevant to the Dry Lake SEZ 

was accomplished through 

(1) a geospatial analysis of 

available ecoregional data and 

(2) expert opinion by the BLM 

interdisciplinary team. Figure 2-7 

presents a conceptual illustration 

of the geospatial framework for 

determining the condition and 

trends of conservation elements 

in the ecoregion. The geospatial 

data used in this assessment are 

available publicly from open 

sources. These data include the 

BLM’s landscape condition model 

for the Mojave Basin and Range, 

modeled land cover types, and 

species-specific habitat suitability 

models. The Mojave Basin and 

Range landscape condition 

model can be used as a proxy for 

landscape intactness. Evaluating 

condition and trends of coarse and 

fine filter conservation elements 

(land cover and habitat models) 

in an ecoregional context will 

provide a better understanding 

of the impacts of solar energy 

development within the Dry Lake 

SEZ relative to the rest of the 

ecoregion. 

The geospatial process for 

quantitatively evaluating condition 

and trends for conservation 

elements (Figure 2-7) begins 

with a characterization of the 

distribution of the conservation 

element within identified analysis 

areas: (1) the entire Mojave Basin 

and Range ecoregion, (2) vicinity 

of the Dry Lake SEZ, and (3) within 

the Dry Lake SEZ developable 

area. These areas are then clipped 

to current and anticipated future 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 15

Geospatial Data

1. Landscape Condition Model1

2. Habitat Suitablity Models2

3. Land Cover Types3

Characterize Distribution:

1. In the ecoregion

2. Within vicinity of the SEZ (5-mi buffer)

3. Within SEZ developable area

Geospatial Overlay Analysis4:

1. Current Development Footprint5

2. 2025 Development Footprint6

CONDITION

TRENDS/

FORECAST

human development footprints3

and forecast trends. Trends are 

understood by using the current 

and future human development 

footprints to evaluate the 

expected future distribution of the 

conservation element relative to its 

current distribution. 

An example table showing the 

condition and trends of various 

coarse and fine filter conservation 

elements in the Mojave Basin and 

Range is shown in Table 2-3. Due 

to the large number of fine scale 

conservation elements that could 

potentially be evaluated, the BLM 

determined that a trends analysis of 

coarse filter land cover types would 

be a suitable habitat-based proxy 

3

 Geospatial data for current and future human development 

footprints are described in more detail in the Mojave Basin and 

Range REA (NatureServe 2013).

for geospatial trends of fine scale 

conservation elements (individual 

species). In Table 2-3, coarse filter 

conservation elements evaluated 

include the Mojave Basin and 

Range landscape condition model 

and the Southwest Regional Gap 

Analysis Project modeled land cover 

types. 

The only fine filter conservation 

element presented in Table 2-3 

is the Mojave population of the 

desert tortoise (Gopherus agassizii), 

which is listed in the table due 

to its threatened status under 

the Endangered Species Act and 

known presence in potentially 

suitable habitat on the Dry Lake 

SEZ. Based on the results presented 

in Table 2-3, it was concluded that 

all conservation elements are 

expected to experience a declining 

trend in the Mojave Basin and 

Range, as all conservation elements 

are expected to experience some 

level of range contraction due to 

human development in the future. 

Landscape condition within the 

Mojave Basin and Range is also 

expected to decline in the future. 

Because the Sonora-Mojave 

Creosotebush-White Bursage 

Desert Scrub comprised the largest 

portion of the Dry Lake SEZ (98.8%), 

the cumulative expected future 

loss of this conservation element 

of 10.26% was considered to be 

a problematic trend among all 

conservation elements relative to 

the Dry Lake SEZ.

1 The landscape condition model is available from and described in the BLM Mojave Basin and Range Rapid Ecoregional Assessment.

2 Habitat suitability models are available from the Southwest Regional Gap Analysis Project.

3 Land cover types are available from the Southwest Regional Gap Analysis Project.

4 The overlay change agent/conservation element analysis was conducted to determine geospatial trends. Geospatial data for the change agent were 

overlayed with the distribution of conservation elements to determine current and future distributions of the conservation elements.

5 Geospatial data for the current human development footprint model are available from and described in the BLM Mojave Basin and Range Rapid 

Ecoregional Assessment.

6 Geospatial data for the future (approximately 2025) human development footprint model are available from and described in the BLM Mojave Basin 

and Range Rapid Ecoregional Assessment.

Figure 2-7. Conceptual diagram for estimating condition and trends of conservation elements in the Mojave Basin

and Range ecoregion for the Dry Lake Solar Energy Zone Solar Regional Mitigation Strategy.
16 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Table 2-3. Condition and trends assessment for coarse and fine filter conservation elements in the Mojave Basin and Range relevant to the Dry Lake Solar 

Energy Zone.

Solar Energy Zone (SEZ) 

Site-Specific Condition 

(SEZ Developable Area)

Condition in the

Vicinity of SEZ

(Local-Regional Status)

Landscape-Ecoregional 

Condition Ecoregional Trendsa

Coarse Filter Conservation Element: Land Cover Types

Description

Potential 

Distribution (Acres) 

Within SEZ

Percent 

Within SEZ 

Relative to 

Distribution in 

Ecoregion

Potential 

Distribution (Acres) 

Within 5 

mi of SEZ 

Boundary

Percent 

Within 5 

mi Area 

Relative to 

Distribution in 

Ecoregion

Potential 

Distribution (Acres) 

Within 

Mojave 

Ecoregion

Percent 

Total 

Distribution Within 

Ecoregion

Current 

Conversion 

to Human 

Development 

(Acres)

Percent 

Current 

Conversion 

Relative to 

Distribution in 

Ecoregion

Future 

Conversion 

to Human 

Development 

(Acres)

Percent 

Future 

Conversion 

Relative to 

Distribution in 

Ecoregion

Natural Land Cover Types

Sonora-Mojave 

Creosotebush-White 

Bursage Desert Scrub

3,428 0.02% 83,300 0.59% 14,085,230 34.73% 1,229,275 8.73% 1,444,510 10.26%

North American Warm 

Desert Wash 14 <0.01% 2,618 0.45% 585,954 1.44% 36,307 6.20% 49,560 8.46%

Sonora-Mojave Mixed 

Salt Desert Scrub 29 <0.01% 645 0.04% 1,486,560 3.66% 370,165 24.90% 401,792 27.03%

North American Warm 

Desert Pavement 1,694 0.30% 570,572 1.41% 21,738 3.81% 22,730 3.98%

North American Warm 

Desert Bedrock Cliff 

and Outcrop

5,144 0.08% 6,082,940 15.00% 159,812 2.63% 177,422 2.92%

Mojave Mid-Elevation 

Mixed Desert Scrub 4,651 0.07% 6,263,875 15.44% 403,753 6.45% 447,348 7.14%

North American Warm 

Desert Playa 287 0.04% 723,597 1.78% 34,661 4.79% 37,391 5.17%

Inter-Mountain Basins 

Semi-Desert Shrub 

Steppe

147 0.02% 866,500 2.14% 29,719 3.43% 37,847 4.37%

Open Water 1 0.00% 234,039 0.58% 4,439 1.90% 5,861 2.50%

North American 

Warm Desert Riparian 

Mesquite Bosque

1 0.01% 17,732 0.04% 3,316 18.70% 3,499 19.74%

Great Basin PinyonJuniper Woodland 2,085,200 5.14% 63,364 3.04% 69,027 3.31%

Sonora-Mojave-Baja 

Semi-Desert Chaparral 24,559 0.06% 1,120 4.56% 1,192 4.86%

Inter-Mountain 

Basins Big Sagebrush 

Shrubland

701,289 1.73% 20,766 2.96% 21,571 3.08%

Disturbance Land Cover Types

Developed, Medium - 

High Intensity 495 0.39% 128,405 0.32% 115,830 90.21% 118,686 92.43%

Invasive Southwest 

Riparian Woodland 

and Shrubland

11 0.02% 52,262 0.13% 20,726 39.66% 24,288 46.47%

TOTAL 3,471 <0.01% 98,994 2.91% 33,908,714 83.60% 2,514,991 7.42% 2,862,724 8.44%

a

 The trend assessment included the current and future (approximately 2025) development footprints to determine the amount of each land cover type that is expected to be converted to 

human developments.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 17

Table 2-3 (continued). 

Solar Energy Zone (SEZ) 

Site-Specific Condition 

(SEZ Developable Area)

Condition in the Vicinity 

of SEZ (Local-Regional 

Status)

Landscape-Ecoregional 

Condition Ecoregional Trendsa

Coarse Filter Conservation Element: Landscape Condition Model

Average Current Condition 

Value Within the SEZ (SD*)

Average Current Condition 

Value Within 5 mi of SEZ 

Boundary (SD*)

Average Current 

Condition Value Within 

Mojave Basin and Range 

Ecoregion (SD*)

Average Future Condition 

Value Within Mojave

Basin and Range

Ecoregion (SD*) 

Average Ecoregional 

Difference in Current and 

Future Condition

Values (%)

Landscape Condition 

Value 57.4 (5.0) 66.0 (9.4) 76.6 (13.8) 72.3 (17.3) -4.3 (5.6%)

Fine Filter Conservation Element: Mojave Desert Tortoise Distribution

Potential Distribution 

(Acres) Within SEZ

Potential Distribution 

(Acres) Within 5 mi of SEZ 

Boundary

Potential Distribution 

(Acres) Within Mojave 

Ecoregion

Future Conversion to 

Human Development 

(Acres)

Percent Future Conversion

Mojave Desert 

Tortoise Potentially 

Suitable Habitat Model 

(SWReGAP)

3,471 92,168 16,772,653 1,059,811 6.3%

*SD = standard deviation 
18 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

2.2.1 Description of 

Existing Rights-ofWay and Impact on 

Developable Area

As stated in Section 2.1, the Dry 

Lake SEZ contains many previously 

developed areas, including a 

natural gas power plant (the Harry 

Allen Generating Station), pipelines, 

a gypsum mining processing 

plant, several known mining 

claims, and three designated 

transmission corridors and rightsof-way (including a 500-kilovolt 

transmission line) (Figure 2-4). 

Subsequent to the signing 

of the Solar PEIS ROD, BLM 

Southern Nevada District Office 

staff revised the developable and 

nondevelopable portions of the 

SEZ to take into account current 

existing land uses on the SEZ. 

Known locations of rights-of-way, 

pipelines, and existing leases 

and mining claims, including 

the natural gas power plant and 

gypsum processing plant, have 

been identified as nondevelopment 

areas within the SEZ. Although 

the total SEZ size is the same as 

that reported in the Final Solar 

PEIS (6,187 acres, or 25 km2), the 

developable area of the SEZ has 

been reduced from 5,717 acres 

(23 km2) to 3,471 acres (14 km2) 

(Figure 2-8).

2.2.2 Description of 

Potential Development 

Utility-scale solar facilities of 

all technology types have a key 

element in common—they all have 

a large solar field with reflectors or 

photovoltaic surfaces designed to 

capture the sun’s energy. The solar 

fields generally require a relatively 

flat land surface; only locations with 

less than 5% slope were included 

as SEZs in the Final Solar PEIS. As 

constructed to date, vegetation is 

generally cleared and solar fields 

are fenced to prevent damage to or 

from wildlife and trespassers. 

In the Final Solar PEIS, 

maximum solar development of the 

Dry Lake SEZ was assumed to be 

80% of the developable SEZ area 

over a period of 20 years. Although 

the developable area has been 

refined to 3,471 acres (14 km2) (see 

Section 2.2.1), for the purposes of 

this assessment, it is assumed that 

more nondevelopment areas will 

be identified in the future and that 

only approximately 3,000 acres 

(12 km2) will be developed (see 

Section 2.5). In the Final Solar PEIS, 

data from various existing solar 

facilities were used to estimate 

that solar trough facilities will 

require about 5 acres/megawatt 

(0.02 km2/megawatt), and other 

types of solar facilities (e.g., 

power tower, dish engine, and 

photovoltaic technologies) will 

require about 9 acres/megawatt 

(0.04 km2/megawatt). Using these 

land requirement assumptions, full 

development of the Dry Lake SEZ, 

assuming the revised developable 

area, would allow development of 

solar facilities with an estimated 

total of between 386 megawatts 

(for power tower, dish engine, or 

photovoltaic technologies) and 

694 megawatts (for solar trough 

technologies) of electrical power 

capacity.

Availability of transmission 

from SEZs to load centers is an 

important consideration for 

future development in SEZs. 

For the proposed Dry Lake SEZ, 

several existing transmission lines, 

including a 500-kilovolt line, run 

through the SEZ. It is possible that 

an existing line could be used to 

provide access from the SEZ to 

the transmission grid, but since 

existing lines may already be at 

full capacity, it is possible that 

at full build-out capacity, new 

transmission and/or upgrades of 

existing transmission lines may be 

required to bring electricity from 

the proposed Dry Lake SEZ to load 

centers. An assessment of the most 

likely load center destinations for 

power generated at the Dry Lake 

SEZ and a general assessment 

of the impacts of constructing 

and operating new transmission 

facilities on those load centers was 

provided in Section 11.3.23 of the 

Final Solar PEIS. Project-specific 

analyses would also be required to 

identify the specific impacts of new 

transmission construction and line 

upgrades for any projects proposed 

within the SEZ.

Since Interstate 15 and 

U.S. Route 93 are adjacent to the 

SEZ, existing road access should be 

adequate to support construction 

and operation of solar facilities. 

It is likely that no additional road 

construction outside of the SEZ 

would be needed.

2.2 General Description of Solar Development

in the Dry Lake Solar Energy Zone
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 19

2.3 Summary of Solar Development Impacts

on the Dry Lake Solar Energy Zone

comprehensive assessment 

of the potential impacts of 

solar development at the 

Dry Lake SEZ was provided 

in the Final Solar PEIS (BLM and 

DOE 2012). Potential adverse 

impacts included effects on nearby 

wilderness areas, recreational use 

of the SEZ lands, military use of the 

SEZ lands, soils, water resources, 

vegetation, wildlife, special 

status species (both vegetation 

and wildlife), air quality, visual 

resources, paleontological and 

cultural resources, Native American 

concerns, and transportation. 

Some potential positive impacts 

of development were identified 

for local socioeconomics, as well 

as positive impacts in terms of 

potential to reduce greenhouse gas 

emissions if solar energy produced 

at the SEZ would displace use of 

fossil fuels. 

A
20 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

2.4 Mitigation Strategy (Hierarchy)

of the Dry Lake Solar Energy Zone 

2.4.1 Avoidance

2.4.1.1 Dry Wash/Riparian Areas

In the Final Solar PEIS and 

the Solar PEIS ROD, 469 acres 

(1.9 km2) of floodplain and wetland 

within the SEZ boundaries were 

identified as nondevelopment 

areas. Avoidance of these areas will 

eliminate or largely reduce adverse 

impacts to them.

2.4.1.2 Existing Rights-of-Way, 

Mining Claims, etc.

As stated in Section 2.2.1, the 

BLM has revised the developable 

and nondevelopable portions 

of the SEZ to take into account 

current existing land uses on the 

SEZ. Known locations of rightsof-way, pipelines, and existing 

leases and mining claims, including 

the natural gas power plant and 

gypsum processing plant, have 

been identified as nondevelopment 

areas within the SEZ. The remaining 

developable area of the SEZ has 

been reduced to 3,471 acres 

(14 km2) (Figure 2-8). This reduction 

in developable area of the SEZ 

also will reduce potential impacts 

identified in the Final Solar PEIS 

(e.g., far fewer acres of habitat 

reduction will occur for vegetation 

and wildlife species, including 

special status species). In addition, 

an eligible archaeological site 

(i.e., Old Spanish Trail/Mormon 

Road) within a right-of-way will be 

avoided. 

Figure 2-8. Dry Lake Solar Energy Zone revised developable area.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 21

2.4.2 Minimization

2.4.2.1 Summary of Programmatic 

Design Features to be Applied 

The Final Solar PEIS identified 

a comprehensive suite of required 

programmatic design features 

that would avoid and/or minimize 

adverse impacts to resources, either 

onsite or through consultation/

coordination with potentially 

affected entities. The programmatic 

design features are extensive 

and are listed in their entirety in 

Appendix A of the Solar PEIS ROD 

(BLM 2012). These programmatic 

design features include required 

actions to avoid or minimize 

impacts to all of the potentially 

impacted resources listed in 

Section 2.3. 

2.4.2.2 Other Required Impact 

Minimization Measures and/or 

Stipulations

The Final Solar PEIS also 

includes SEZ-specific design 

features for all of the SEZs. The SEZspecific design features identified 

for the Dry Lake SEZ were the 

following:

Water resources: Groundwater 

analyses suggest that full buildout of dry-cooled and wet-cooled 

technologies is not feasible; for 

mixed-technology development 

scenarios, any proposed dry- or 

wet-cooled projects should use 

water conservation practices.

Wildlife (mammals): The 

fencing around the solar energy 

development should not block 

the free movement of mammals, 

particularly big game species. 

Cultural resources: 

Coordination with the trail 

administration for the Old 

Spanish Trail and Old Spanish Trail 

Association is recommended for 

identifying potential mitigation 

strategies for avoiding or 

minimizing potential impacts on 

the congressionally designated 

Old Spanish National Historic Trail 

and also on any remnants of the 

National Register of Historic Placeslisted sites associated with the 

Old Spanish Trail/Mormon Road 

that may be located within the 

SEZ. Avoidance of the Old Spanish 

Trail site within the southeastern 

portion of the proposed SEZ is 

recommended. 

Native American concerns: 

The Moapa Band of Paiute Indians 

have specifically requested formal 

government-to-government 

contact when construction or 

land management projects are 

being proposed on and/or near 

the Muddy River, Virgin River, 

Colorado River, Arrow Canyon 

Range, Potato Woman, and Apex 

Pleistocene Lake. Compensatory 

programs of mitigation could be 

implemented to provide access 

to and/or deliberately cultivate 

patches of culturally significant 

plants within the Dry Lake SEZ 

or on other public lands nearby 

where tribes have ready access. 

The BLM should consider assisting 

the Moapa Band of Paiute Indians 

with the preparation of forms to 

nominate identified sacred places 

as traditional cultural properties, 

if it is found that all the proper 

eligibility requirements are met. 

Some additional minimization 

measures would likely be identified 

during preparation of a NEPA 

analysis to support a competitive 

lease offering within the SEZ. 

These measures would also be 

incorporated into the lease offering 

as stipulations. For example, if 

any archaeological sites are found 

during the cultural resource 

inventory (see text box titled Dry 

Lake Cultural Resources) and are 

determined to be eligible for 

listing in the National Register of 

Historic Places, onsite mitigation 

or avoidance strategies will be 

considered during consultation 

with the BLM-Nevada state historic 

preservation officer and affected 

tribes to minimize impacts on 

significant cultural resources.

2.4.3 Regional Mitigation

Identifying the impacts of 

utility-scale solar development 

that may warrant regional 

mitigation involves three steps: 

(1) identifying all the potential 

impacts; (2) identifying which 

of the potential impacts are 

likely to be unavoidable (i.e., the 

impacts that cannot be mitigated 

onsite by avoidance and/or the 

implementation of design features 

meant to minimize the impact); 

and (3) identifying which of the 

unavoidable impacts may warrant 

regional mitigation by taking into 

consideration the condition and 

trend of the impacted resources 

in the region and how they could 

be affected by the unavoidable 

impacts.

As part of the Dry Lake SRMS 

process, a team of specialists from 

the BLM Southern Nevada District 

Office (called the interdisciplinary 

team) reevaluated the potential 

impacts of solar development that 

were described in the Final Solar 

PEIS (see Section 2.3) in the light 

of available data specific to the 

SEZ area. This team, along with 

other BLM subject matter experts 

and Argonne National Laboratory 

subject matter experts, followed 

the methodology presented in 

Sections 2.4.3.1 and 2.4.3.2 for first 

identifying unavoidable impacts 

from solar development in the 

SEZ, and then for identifying the 

unavoidable impacts that may 

warrant regional mitigation.
22 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

2.4.3.1 Identification of 

Unavoidable Impacts

The following methodology 

was used to identify unavoidable 

impacts:

•	 The interdisciplinary team

verified/augmented the affected 

environment and impacts 

presented in the Final Solar PEIS 

(for completeness, reviewed 

analysis in both the Draft and 

Final Solar PEIS).

- Reviewed the affected 

environment and the direct, 

indirect, and cumulative 

impacts for each resource 

value presented in the Final 

Solar PEIS. 

- Evaluated whether the 

description of the affected 

environment and impacts 

was comprehensive and 

accurate and whether 

more detailed information 

was available that could 

influence the description of 

impacts as provided in the 

PEIS. Where applicable, new 

information was documented 

(see Appendix A, Impact 

Assessment Summary Table). 

•	 The team verified/augmented

the programmatic and SEZspecific design features 

presented in Appendix A of the 

Final Solar PEIS.

- Reviewed the programmatic 

and SEZ-specific design 

features presented in the 

Final Solar PEIS, determined 

which design features 

are applicable to the Dry 

Lake SEZ, and determined 

if there are additional 

measures that could be 

implemented to avoid and/

or minimize impacts onsite. 

Where applicable, this was 

Dry Lake Cultural Resources

Following the process for evaluating cultural resources outlined in Appendix E of the BLM technical reference, titled “Procedural Guidance for 

Developing Solar Regional Mitigation Strategies” the BLM interdisciplinary team determined cultural resources at the Dry Lake SEZ could most 

likely be mitigated onsite and would not require regional mitigation. 

At the time of the pilot Dry Lake SEZ Solar Regional Mitigation Planning Project, a relatively high percentage of the Dry Lake SEZ (well over 20%) 

had been previously surveyed and/or had been previously disturbed during other industrial activities (e.g., power generation, transmission, 

mining/milling) with few known sites recorded. A segment of the Old Spanish Trail/Mormon Road (not identified as part of the congressionally 

designated national historic trail) was previously evaluated and determined significant; it is listed as part of a National Register historic district. 

Because of its proximity to two washes already established as avoidance areas and a set of existing transmission line rights-of-way, it was 

determined by the interdisciplinary team that any potential impacts on the cultural site (road) are “avoidable,” and no development with the 

potential to impact the site would be approved in that portion of the SEZ (see Section 2.4.1.2). No other National Register-eligible sites were 

known within the SEZ at the time of the pilot. An archaeological inventory of the unsurveyed portions of the SEZ is scheduled to be completed 

prior to offering the SEZ for competitive lease.

In the case of the pilot, it was determined by the interdisciplinary team that a regional approach to mitigation planning did not make sense for 

the Dry Lake SEZ because other SEZs would not likely benefit (not in same region) and because little cost savings and efficiency could be gained 

with so little survey needed. It was also assumed that the few significant sites that might be found in the SEZ during the future inventory could 

be mitigated most effectively onsite (i.e., within the SEZ) using traditional methods and in consultation with the state historic preservation 

officer and tribes. The cultural resource mitigation planning for the Dry Lake SEZ was able to be stopped at this point, and it was concluded that 

standard procedures for addressing cultural resource impacts made the most sense; the standard procedures would complete the inventory and 

evaluation and mitigate for any significant sites within the SEZ.

In addition, consultation with the Moapa Band of Paiute Indians and other tribes had not identified archaeological/cultural resources significant 

to them in the SEZ, although resources in the surrounding areas had been identified through an ethnographic study (SWCA and University of 

Arizona 2011). At the time of the pilot, the BLM was still seeking clarifications from the Moapa on whether portions of the Salt Song Trail or other 

traditional trails crossed the SEZ and whether cultural resource impacts of interest to the tribe were possible. This issue has not yet been resolved. 

Based on feedback during the pilot Dry Lake SEZ Solar Regional Mitigation Planning Project workshops, the Moapa were most concerned about 

impacts on habitat, wildlife, and water use.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 23

documented (see Appendix 

A, Impact Assessment 

Summary Table).

•	 The team identified the impacts

that could be mitigated onsite 

through avoidance and/or 

minimization, including the 

required design features and 

additional measures described 

previously.

- For each resource, the design 

features and additional 

avoidance and minimization 

measures were evaluated 

as to the degree that they 

could avoid and minimize the 

impacts. 

•	 The residual impacts were

considered to possibly 

warrant regional mitigation 

(see Section 2.4.3.2).

The summary table presented 

in Appendix A documents the basis 

for the identification of unavoidable 

impacts for the Dry Lake SEZ.

2.4.3.2 Unavoidable Impacts that 

May Warrant Regional Mitigation

2.4.3.2.1 Conceptual Models 

A conceptual model or models 

depicting interrelationships 

between key ecosystem 

components, processes, and 

stressors at the Dry Lake SEZ 

is needed to evaluate the 

effectiveness of mitigation 

investments employed through an 

SRMS. The Dry Lake SEZ specialist 

team constructed conceptual 

models to explain the role that 

resources, individually and in 

concert with one another, play 

in the function of the relevant 

ecological, social, and cultural 

systems present in the region. 

This regional model provided the 

context to identify critical resources 

at the local scale. Information 

sources used for the development 

of the conceptual model included:

•	 BLM REAs.

•	 BLM RMPs.

•	 Resource specialist expert

opinion.

•	 Nature Conservancy ecoregional

assessments.

•	 Habitat conservation plans.

Additional resources (e.g., 

other baseline resource surveys, 

inventories, occurrence records, 

studies/research, assessments, 

and plans providing insight into 

regional conditions and trends; 

ethnographic studies; BLM, county, 

or regional land use plans; and 

federal, state, or local social and 

economic studies) could be used to 

refine the models in the future. 

Developing conceptual 

models for the Mojave Basin and 

Range ecosystem, for solar energy 

development, and for solar energy 

development at the Dry Lake SEZ 

was an iterative process between 

the BLM and the stakeholders, with 

a goal of describing in detail the 

processes essential to sustain the 

ecosystem and the stressors that 

influence those processes. These 

conceptual models are presented in 

Appendix B. 

2.4.3.2.2 Unavoidable Impacts that May 

Warrant Regional Mitigation

Based on the best available 

information, conceptual models, 

assessments, and expert opinion, 

the Dry Lake specialist team 

identified at-risk resources and 

processes in the region that 

coincided with resources as likely 

experiencing unavoidable adverse 

impacts due to solar development 

within the SEZ. The Sonora-Mojave 

Creosotebush-White Bursage Desert 

Scrub community was identified 

as at risk on the basis of the 

regional trend analysis described in 

Section 2.1.3.2. The team estimated 

how the unavoidable impacts of 

solar development could affect the 

condition and trend of the at-risk 

resource values at both local and 

regional scales. 

For each unavoidable impact, 

the Dry Lake specialist team 

identified criteria to help determine 

at what point the degree of 

unavoidable impacts might warrant 

regional mitigation. The criteria/

decision point referenced: 

a. The relative importance placed 

on the resource in the land use 

plan. 

b. The rarity, legal status, or state 

or national policy status of the 

resource.

c. The resilience of the resource in 

the face of change and impact. 

Next, a team applied the criteria 

to the assumed full build-out of the 

SEZ to identify which unavoidable 

impacts, in the context of the 

regional setting, may warrant 

regional mitigation for the Dry 

Lake SEZ. This list has been 

reviewed by stakeholders, and 

their comments have been 

considered. The process for 

assessing whether impacts to visual 

resources at the Dry Lake SEZ may 

warrant regional mitigation is 

presented in Appendix C. 
24 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

2.5 Regional Mitigation Goals 

2.5.1 Background on 

Regional Goals 

The regional mitigation 

described in this strategy is focused 

on recommending appropriate 

compensation for the unavoidable 

impacts of developing the Dry Lake 

SEZ (i.e., those impacts that cannot 

be either avoided or minimized 

onsite and are likely to exacerbate 

problematic regional trends). 

For impacts recommended for 

regional mitigation, the mitigation 

goal, at the broadest level, is to 

offset the unavoidable adverse 

impacts that are expected to 

occur onsite with actions that 

improve or protect the impacted 

resource elsewhere in the region. 

As detailed in the “Procedural 

Guidance for Developing Solar 

Regional Mitigation Strategies” 

(BLM forthcoming), regional 

mitigation goals should include 

consideration of the effectiveness, 

feasibility, durability, and risk of 

mitigation locations and actions 

for compensating for unavoidable 

impacts in the SEZ.

The unavoidable impacts that 

may warrant regional mitigation 

for the Dry Lake SEZ (identified 

in previous steps in this strategy 

process) are as follows:

•	 The loss of desert tortoise

habitat and the potential loss 

of individual desert tortoises. 

The desert tortoise is listed as 

a threatened species under the 

Endangered Species Act. 

•	 The loss of habitat and the

potential loss of individual 

animals for the following 

BLM special status species: 

Gila monster, Mojave Desert 

sidewinder, ferruginous hawk, 

golden eagle, loggerhead shrike, 

and Le Conte’s thrasher. 

•	 The loss of rosy two-toned

penstemon (also known as 

pinto beardtongue) habitat and 

the potential loss of individual 

plants. The rosy two-toned 

penstemon is a BLM special 

status species plant.

•	 The loss of ecosystem services

and the human uses depending 

on them, as a result of 

development and until the lease 

expires and the site is restored. 

The primary components of 

an ecological system are: soils, 

vegetation, water, air, and 

wildlife. 

•	 The visual impacts that will

occur that exceed the allowable 

level within the portion of the 

SEZ located within the area 

designated as visual resource 

management (VRM) Class III in 

the Las Vegas RMP (BLM 1998).

In addition, the following 

unavoidable impacts were 

identified as having the potential 

to occur, depending on the way 

the area is developed, the success 

of onsite mitigation activities, 

data gaps, and/or the discovery of 

unanticipated resources:

•	 Introduction and spread of

invasive/noxious weeds.

•	 Alterations to surface hydrology.

•	 Loss of cultural resources.

•	 Increased density of desert

tortoise in the Coyote Springs 

ACEC (established for tortoise 

recovery).

•	 Visual resources as seen from

nearby specially designated 

areas.

•	 Certain Native American

concerns (e.g., loss of habitat and 

spiritual value).

While no regional mitigation 

objectives are proposed for these 

potential impacts, they will be 

the focus of an elevated level of 

monitoring so as to facilitate the 

timely detection of unanticipated 

impacts and conditional 

stipulations to be included in the 

grant to afford prompt and effective 

remediation.

2.5.2 Las Vegas Resource 

Management Plan Goals 

and Objectives 

The Las Vegas RMP (BLM 

1998) guides BLM project-specific 

decisions in the region in which 

the Dry Lake SEZ is located. The 

Las Vegas RMP established the 

following management goals 

and objectives related to the 

unavoidable impacts identified in 

2.5.1 for the Dry Lake SEZ:

Desert Tortoise

•	 Manage habitat to further

sustain the populations of 

federally listed species so they 

no longer need protection under 

the Endangered Species Act. 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 25

•	 Manage desert tortoise habitat

to achieve the recovery criteria 

defined in the “Desert Tortoise 

(Mojave Population) Recovery 

Plan” (Brussard et al. 1994) and 

ultimately to achieve delisting of 

the desert tortoise.

Special Status Species Animals

•	 Manage habitats for nonlisted

special status species to support 

viable populations so future 

listing is not necessary.

Special Status Species Plants

•	 Manage habitats for nonlisted

special status species to support 

viable populations so future 

listing is not necessary.

Ecosystem Loss

•	 Restore plant productivity on

disturbed areas of public lands.

•	 Reduce erosion and

sedimentation while 

maintaining, or where possible, 

enhancing soil productivity 

through the maintenance and 

improvement of watershed 

conditions.

•	 Support viable and diverse

wildlife populations by providing 

and maintaining sufficient 

quality and quantity of food, 

water, cover, and space to satisfy 

needs of wildlife species using 

habitats on public land.

Visual Resources

•	 Manage (VRM Class III) for

partial retention of the existing 

character of the landscape. In 

these areas, authorized actions 

may alter the existing landscape 

but not to the extent that they 

attract or focus the attention of 

the casual viewer.

2.5.3 Dry Lake Solar

Energy Zone Mitigation 

Goals and Objectives 

The following Dry Lake SEZspecific regional mitigation goals 

and objectives were developed 

using the “Procedural Guidance 

for Developing Solar Regional 

Mitigation Strategies” (BLM 

forthcoming). They are highlevel goals and objectives to be 

considered in selecting mitigation 

locations and actions and to serve 

as a framework for identifying 

site-specific mitigation goals and 

objectives (see Section 2.7). 

Desert Tortoise

•	 Goal: Mitigate unavoidable

impacts to further sustain the 

populations of federally listed 

species so they no longer 

need protection under the 

Endangered Species Act.

•	 Objective: Comply with the

permit (Endangered Species Act, 

Section 7) issued to the BLM by 

the U.S. Fish and Wildlife Service 

for disturbance of tortoise 

habitat in the Southern Nevada 

District Office RMP area. Collect 

the Section 7 mitigation fee 

(currently $824 per acre) for use 

in supporting the recovery of the 

species.

Special Status Species Animals

•	 Goal: Manage habitats for

nonlisted special status species 

to support viable populations so 

future listing is not necessary.

•	 Objective: Mitigate the loss

of habitat by restoring and/

or protecting habitat in the 

same region in which the SEZ is 

located.

Special Status Species Plants

•	 Goal: Mitigate the loss of plants

and habitat for the rosy twotoned penstemon to support 

viable populations in which the 

SEZ is located so future listing of 

the plant is not necessary.

•	 Objective 1: Protect genetic

diversity by seed collection 

before disturbance.

•	 Objective 2: Secure basic

scientific information pertaining 

to the rosy two-toned 

penstemon.

Ecosystem Services

•	 Goal: Restore and/or preserve

the creosote-bursage vegetation 

community disrupted by 

development (taking into 

account the existing landscape 

condition in the SEZ).

•	 Objective: Restore and/or

preserve the creosote-bursage 

vegetation community and 

ecosystem proportionate to 

the condition of this same 

ecosystem in the Dry Lake SEZ 

and, where possible, in concert 

with protection/restoration of 

special status species (animal 

and plant) habitat.

Visual Resources

•	 Goal: Restore and/or protect the

visual resource values altered 

by development of the SEZ 

(taking into account the existing 

condition of visual resource 

values in the Dry Lake SEZ).

•	 Objective: Restore and/or

protect visual resource values 

proportionate to expected 

impacts in concert with 

ecosystem restoration.
26 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

2.6 Calculating the Recommended Mitigation

Fee for the Dry Lake Solar Energy Zone

he mitigation fee is 

intended to be a one-time 

fee paid by a developer 

for the acres being 

disturbed by development. While 

the fee is assessed once, before 

development commences, it should 

be administered over the life of the 

solar project. The actual fee for the 

Dry Lake SEZ should be developed 

just prior to leasing. An example 

calculation of the fee is provided 

here for illustration purposes. 

The regional mitigation fee 

for the Dry Lake SEZ is calculated 

according to the “Procedural 

Guidance for Developing Solar 

Regional Mitigation Strategies (BLM 

forthcoming). For the Dry Lake SEZ, 

the fee can be calculated as follows:

Project mitigation fee = 

(number of acres) X

(per acre regional mitigation fee)

The specific methods and 

values used to calculate the peracre regional mitigation fee can 

vary between SEZs and involve a 

number of different calculations. 

Figure 2-9 presents a flow diagram 

describing the various potential 

pathways that can be used to 

calculate the per-acre regional 

mitigation fee. The example 

process used at the Dry Lake SEZ is 

highlighted in yellow in the figure. 

The steps that follow correspond 

to Figure 2-9 and outline the 

calculation of and example regional 

mitigation fee for the Dry Lake SEZ. 

T

Figure 2-9. Steps for calculating per-acre regional mitigation fees.

Final Per-Acre SEZ Regional Mitigation Fee

Subtract Any Applicable Pre-Acre ESA Fee

Add Per-Acre Effectiveness and Durability Fee

Add Per-Acre Acquisition, Restoration, and Preservation Fees (if applicable)

Consider SEZ Adjustment

Multiple Per-Acre Fee by

Landscape Condition Index

Conduct Market Analysis to Determine

Per-Acre Acquisition/Restoration Costs

Determine Total Costs for

Specific Protection Actions

Add Costs of Protection

Actions and Divide by SEZ Acreage

Select Appropriate Mitigation Technique(s)

STEP 1

STEP 2

STEP 3

STEP 4

STEP 5

STEP 6

STEP 7

Acquisition Restoration Preservation
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 27

Step 1: Select Mitigation 

Action(s) and Location(s): As 

described in Section 2.8, the 

recommended mitigation actions/

location are: (1) increase law 

enforcement and monitoring 

activities to halt the trend in 

degradation of resource values; and 

(2) restore disturbed areas in the 

Gold Butte ACEC.

Step 2: Calculate the Base Fee: 

The market analysis for the Dry 

Lake SEZ mitigation consisted of 

a BLM economist querying local 

contractors for the cost of restoring 

an acre of burn scar to the creosotebursage vegetative community (the 

main vegetative community at Dry 

Lake). The BLM determined that 

the cost of restoration was roughly 

$10,000 per acre.

Example: Base Per-Acre Mitigation 

Fee = $10,000

Step 3: Calculate the Adjusted 

Base Fee: Since the base per-acre 

mitigation fee calculated in Step 2 

represents the costs of restoring a 

completely altered landscape, it is 

necessary to adjust the restoration 

fee to reflect the actual landscape 

conditions within the SEZ. To 

do this, the base mitigation fee 

calculated in Step 2 is multiplied 

by the landscape condition index, 

which for the Dry Lake SEZ is 52.8% 

(NatureServe 2013). 

Example: Adjusted Base Per-Acre 

Mitigation Fee = ($10,000 x 0.528) = 

$5,280

Step 4: Consider SEZ 

Adjustment: For some SEZs, the 

BLM may apply an adjustment 

intended to direct solar 

development to the SEZ and 

account for degraded site-specific 

habitat conditions not considered 

in Step 3. The BLM may use this 

discretion, on a case-by-case basis, 

to identify appropriate terms 

and conditions—including those 

relating to mitigation—for FLPMA 

Title V right-of-way authorizations. 

The BLM recommends an 

adjustment of 50% for the Dry Lake 

SEZ.

Example: Recommended Dry 

Lake SEZ Adjusted Base Per-Acre 

Mitigation Fee = ($5,280 x 0.50) = 

$2,640

Step 5: Add Per-Acre 

Acquisition, Restoration, and 

Preservation Fees: There are no 

acquisitions proposed for the Dry 

Lake SEZ. The costs of increased law 

enforcement and monitoring are 

added in Step 6.

Step 6: Add Per-Acre 

Effectiveness and Durability Fee: 

To ensure all mitigation techniques 

chosen in Step 1 are effective 

and durable, a standard BLM 

effectiveness and durability fee 

should be applied to regional 

mitigation fees. Table 2-4 details 

how this fee is calculated. This fee 

is simply added to the per-acre fee 

calculated in Step 5. 

Example: Recommended Dry 

Lake SEZ Adjusted Base Per-Acre 

Mitigation Fee = ($2,640 + $20) = 

$2,660

Table 2-4. Estimate of funding needed for 

management activities to ensure effectiveness 

and durabilitya.

Tasks Per Acre/

Per Year

Law enforcement $15

Effectiveness monitoring $5

TOTAL $20

Annual rate for 5,000-acre SEZ $100,000

Total 30-year management 

fee/5,000-acre SEZ $3,000,000

a The cost estimates were derived from a cursory market 

analysis and will be finalized once competitive interest 

is received.

Step 7: Subtract Any Applicable 

Endangered Species Act Section 7 

Fees: The Dry Lake SEZ is in an area 

subject to Section 7 permitting for 

the desert tortoise, a species listed 

under the Endangered Species Act 

as threatened. The Endangered 

Species Act Section 7 mitigation 

fee for Clark County, where the SEZ 

is located, is $824 per acre. Each 

developer is required to pay this 

fee, and the funds are expended in 

pursuit of species recovery. Because 

the expenditure of Section 7 fees is 

consistent with Dry Lake regional 

mitigation goals and objectives 

(see Section 2.5.3), the Section 7 

mitigation fee is subtracted from 

the base fee to avoid duplicate 

payment. The fee amount will still 

be charged to the developer and 

expended for mitigation of impacts 

to desert tortoise in consultation 

with the U.S. Fish and Wildlife 

Service.

Example: Recommended Dry Lake 

SEZ Per-Acre Mitigation Fee = $2,660 - 

$824 = $1,836
28 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

2.7 Management of Solar

Regional Mitigation Fees

he BLM will select 

management options for 

SEZ mitigation fees that are 

consistent with the BLM’s 

interim policy, draft Manual Section 

1794, “Regional Mitigation,” issued 

June 13, 2013, which includes 

guidance for management of funds 

collected as part of the restoration, 

acquisition, or preservation portion 

of the total mitigation fee by an T

independent third party. 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 29

2.8 Evaluation of Mitigation Locations,

Objectives, and Actions

he proposed regional 

mitigation locations and 

actions will mitigate for the 

temporary loss of some 

of the resources that will occur 

as a result of solar development 

in the Dry Lake SEZ (e.g., loss of 

creosote-bursage vegetation, loss 

of general and BLM special status 

species habitat, loss of cryptobiotic 

soil crusts and desert pavement, 

and loss of the ecosystem services 

these resources provide). The 

BLM Southern Nevada District 

Office considered several regional 

mitigation action alternatives. The 

suite of potential mitigation actions 

were generated by soliciting 

proposals from the public and 

from BLM staff in the district. The 

proposals included:

•	 Restoring disturbed land in

several ACECs and one national 

conservation area in the vicinity 

of the Dry Lake SEZ.

•	 Preventing further degradation

in several ACECs and one 

national conservation area in the 

vicinity of the Dry Lake SEZ.

•	 Acquiring private land in the

vicinity of the Dry Lake SEZ and 

managing it for conservation 

values. 

The following proposed 

mitigation locations were screened 

and given a preliminary ranking 

using criteria based on the regional 

mitigation goals described in 

Section 2.5. The results of the 

ranking are summarized in the 

screening table for candidate 

regional mitigation locations for the 

Dry Lake SEZ (Appendix D): 

•	 Gold Butte ACEC.

•	 Mormon Mesa ACEC.

•	 Coyote Springs ACEC.

•	 Piute-Eldorado Valley ACEC.

•	 Coyote Springs ACEC, plus

adjacent lands as proposed by 

the The Nature Conservancy. 

The following criteria were used 

to screen and rank these sites: 

•	 The sites are within the Las

Vegas Field Office (i.e., the 

same subregion and landscape 

context as the Dry Lake SEZ). 

•	 The sites contain the same

creosote-bursage vegetation 

community. 

•	 The sites are within desert

tortoise critical habitat. Regional 

mitigation for the Dry Lake 

SEZ would indirectly benefit 

conservation and recovery 

efforts for the desert tortoise. 

•	 The sites provide habitat for a

similar suite of general wildlife, 

special status wildlife, and rare 

plants.

•	 The sites are in a higher VRM

class than the Dry Lake SEZ. 

Improvements provided by 

regional mitigation for the 

Dry Lake SEZ would result in 

improvements to a higher VRM 

class. 

•	 The degree to which the

mitigation site and actions are 

consistent with the Las Vegas 

RMP.

•	 The degree to which applicable

management prescriptions in 

the Las Vegas RMP (BLM 1998) 

facilitate durable mitigation 

investments. Management 

prescriptions that facilitate 

durability include, but are not 

limited to: special conservationoriented designations, such as 

national conservation areas, 

ACECs, designated wilderness 

areas, and wilderness study 

areas; areas where landdisturbing activities are 

prohibited; and areas where 

land-disturbing activities are 

discouraged. 

Proposed Mitigation Actions 

and Locations. The Gold Butte 

ACEC is preliminarily recommended 

as the best recipient location for 

regional mitigation from the Dry 

Lake SEZ. This ACEC is located 32 

miles (51 km) east of the Dry Lake 

SEZ (see Figure 2-10). This ACEC 

is recommended based on the 

following reasons:

•	 The Mojave Basin and Range REA

(NatureServe 2013) suggests that 

creosote-bursage vegetation in 

the Gold Butte ACEC may persist 

longer under climate change 

than the other nominated 

ACECs. 

•	 Niche modeling, completed by

the National Park Service for the 

Lake Mead National Recreation 

Area, suggests, under future 

climate change, high-quality 

desert tortoise habitat will 

remain in the Gold Butte ACEC 

while most of the adjacent 

desert tortoise habitat in the 

national recreation area will 

decline and disappear.

T
30 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

•	 Road decommissioning and

restoration is proposed as a Dry 

Lake SEZ regional mitigation 

activity. The Gold Butte ACEC 

has already completed road 

designations. Road designations 

have not been completed on the 

other ACECs.

•	 Reseeding burn scars is

proposed as a Dry Lake SEZ 

regional mitigation activity. 

The Gold Butte ACEC suffered 

multiple wildfires in 2005 and 

2006 and could benefit from 

restoration. The other ACECs 

have had fewer fires.

•	 The Gold Butte ACEC is an

important landscape corridor 

between Lake Mead and the 

Virgin Mountains for game 

species managed by the Nevada 

Department of Wildlife. 

The Gold Butte ACEC was 

established in the Las Vegas RMP 

(BLM 1998). It has an area of 

approximately 350,000 acres (1416 

km2). The primary resource values 

listed in the RMP are:

•	 Cultural and historic resources.

•	 Scenic values.

•	 Wildlife habitat.

•	 Special status species habitat.

•	 Botanical resources.

The Las Vegas RMP also 

specifies the resource constraints of 

the Gold Butte ACEC, which include:

•	 Closed to mineral entry, sale, and

leasing, except for fluid minerals 

under certain circumstances.

•	 Closed to grazing.

•	 Managed for wild burros at an

appropriate management level 

of 98 animals.

•	 Off-road vehicle use limited to

existing roads and trails.

•	 Closed to off-road vehicle events.

•	 Right-of-way avoidance.

The resource values found in 

the Gold Butte ACEC are threatened 

by: unauthorized activities, 

including off-road vehicle use, 

illegal dumping, and trespass 

livestock grazing; wildfire; and weed 

infestation. Existing burned areas, 

unauthorized roads and trails, and 

areas disturbed by other activities 

await funding for rehabilitation. 

Neutralizing these threats and 

restoring altered ecological systems 

are the focus of the regional 

mitigation proposed for this area.

Two action-specific mitigation 

goals and nine mitigation 

objectives are recommended to be 

undertaken to compensate for the 

unavoidable impacts associated 

with the development of the Dry 

Lake SEZ (see Table 2-5). Some of 

these objectives are associated 

with preventing degradation in 

the Gold Butte ACEC. The total cost 

of affecting the protection of this 

ACEC for 30 years, the expected 

term of a solar development rightof-way, is about $9 million. The 

Gold Butte ACEC is about 350,000 

acres, and the cost is about $25.92 

per acre. The total mitigation fee 

expected to be collected for the 

Dry Lake SEZ if full build-out of 

the 3,591 developable acres in the 

SEZ occurs is approximately $6.6 

million (see Section 2.6). Mitigation 

funds from a single SEZ will not 

likely be the only source of funding 

for a given regional mitigation 

effort, such as restoration in the 

Gold Butte ACEC. State and federal 

agencies, including the BLM, 

should identify opportunities for 

pooling financial resources from 

additional developments required 

to implement regional mitigation 

actions.

The restoration goals in the 

Gold Butte ACEC are to:

1. Prevent further degradation 

of the ACEC, and ensure the 

durability of the conservation 

investment by:

a. Augmenting BLM law 

enforcement capacity 

sufficient to maintain 

ranger patrols in the ACEC. 

b. Providing a monitor to track 

activities in and impacts to 

the ACEC.

c. Building the capacity to 

respond in a timely manner 

to activities that threaten 

resource values.

d. Providing treatment 

for noxious weeds and 

maintaining fuel breaks to 

protect the area. 

2. Restoring creosote-bursage 

vegetation on closed roads, 

burn scars, and other 

anthropogenic impacts. 

Included in this goal is the 

procurement of genetically 

appropriate native seed to 

complete these restoration 

activities. 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 31

Figure 2-10. Gold Butte Area of Critical Environmental Concern.
32 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Table 2-5. Dry Lake Solar Energy Zone goals and objectives associated with mitigation in the Gold Butte Area of Critical Environmental Concern.

Mitigation Goals and Tasks Reason Why Mitigation Funds May Be Needed Measurable Objectives Indicators

Goal 1: Prevent further 

degradation of the

ACEC, and ensure the

durability of the

conservation investment

in the Gold Butte ACEC. 

The purpose of Goal 1 is to address the primary long-term threats to 

any ACEC that is selected as a recipient site for Dry Lake SEZ regional 

mitigation. Addressing these long-term impacts will provide the 

durability requested by the public. 

Increase acreage of 

healthy lands, and

decrease unauthorized 

use and other disturbances.

Acres of disturbed and untreated land in the Gold 

Butte ACEC (measured annually). Breakout by 

type of disturbance: wildfire, illegal dumping, 

unauthorized off-highway vehicle use, unauthorized campsites, noxious weed incursion, etc.

Acres of treated land in the ACEC (treated, but 

has not reached a condition to be considered 

restored). Breakout by type of treatment.

Task 1.1: Augment law

enforcement. 

Law enforcement staff is limited within the BLM. Instead of dedicated 

base funding, law enforcement officers (LEOs) are funded out of benefitting programs (such as wildlife, range, and forestry). With limited 

funding, BLM program managers must choose between implementing 

mandated activities and funding LEOs. In the Southern Nevada District, 

there are six rangers outside of the Red Rock Canyon National Conservation Area. Providing regional mitigation to fund one LEO dedicated 

to patrol the ACEC is an effective way to manage public use and ensure 

compliance with area resource management objectives, such as those 

that protect cultural and historic resources, scenic values, wildlife 

habitat, special status species habitat, and botanical resources.

After establishing the 

baseline, reduce the 

number of incidents in 

5 years by 75% and in 

10 years by 90%, with a 

goal of 0 incidents.

Number and nature of incidents of

noncompliance. 

Number of sites and resources protected by law 

enforcement.

Note: With a greater law enforcement presence, 

the number of reported incidents may increase at 

first. Will need to normalize data to compensate.

Task 1.2: Monitor small disturbances from anthropogenic 

impacts (such as off-highway 

vehicle incursions, dump sites, 

campsites, and target shooting 

areas) and treat with signs, 

fencing, restoration, etc.

Monitoring and responding quickly to small disturbances is the best 

way to limit their size and extent while positively shaping public use. 

Current resource management demands on staff time limit the BLM’s 

ability to respond to minor impacts quickly before they grow into 

larger problems.

Reduce the number of 

incidents and increase 

the response time, once a 

baseline for incidents and 

response time has been 

established.

Number of incidents of “small disturbances.” 

Note: The number of reported incidents may 

increase with increased level of monitoring. Need 

to normalize data to compensate.

Number of rapid responses to disturbances 

(breakout by type of disturbance).

Task 1.3: Monitor and treat 

noxious weeds.

Noxious weeds, such as Sahara mustard, are a significant threat to 

Mojave Desert ecosystems. Monitoring roads and trails and responding 

quickly to incipient weed populations is the only way to preserve intact 

ecosystems and prevent large infestations that cannot be treated. BLM 

funding to accomplish this task is limited. 

Reduce the presence of 

noxious weeds by X% in 

Y years—a measurable 

objective can be set after 

establishing a baseline.

Acreage of noxious weeds (measured annually).

Number of weed monitoring reports.

Number and acres of weed treatments (measured 

annually or seasonally). 

Task 1.4: Implement, monitor, 

and maintain fuel breaks.

Fire is a significant threat to Mojave Desert ecosystems. Constructing 

fuel breaks that work in concert with natural and manmade barriers is 

an important way to compartmentalize and protect intact vegetation 

and Mojave ecosystems from large-scale fires, similar to the fires 

southern Nevada experienced in 2005.

Reduce incidence and 

spread of fires.

Number of fires and cause. Acreage of lands 

affected by fire.

Number and nature of fuel reduction projects.

Task 1.5: Monitor and periodically evaluate land health and 

management effectiveness.

Periodically monitoring and evaluating the effectiveness of resource 

management is a critical part of long-term adaptive management. 

Monitoring any recipient site will need to be a part of Dry Lake Solar 

Energy Zone regional mitigation. 

Meet rangeland health 

assessment objectives. Refer to rangeland health assessment indicators.

Goal 2: Restore

creosote-bursage

vegetation and the

ecosystem services it

provides on closed roads, 

burn scars, and other

anthropogenic

disturbances within the 

Gold Butte ACEC. 

There are two important reasons why regional mitigation funding 

should be used to meet Goal 2: (1) There is not dedicated BLM base 

funding to decommission roads and trails that have been closed 

through designations; and (2) Emergency stabilization and rehabilitation funding is not appropriate for nonemergency restoration projects, 

and burned area rehabilitation funding is limited to 3 to 5 years. 

This timeframe is not practical given Mojave Desert recovery times. 

Currently, restoration needs go unmet or are funded inconsistently 

through one-time and soft money opportunities. The collection and 

use of regional mitigation funds to restore roads and other disturbed 

sites (such as old burn scars) would not replace BLM base funding. 

Increase acreage of land 

treated.

Acres of disturbed and untreated creosotebursage vegetation in the Gold Butte ACEC 

(measured annually). Breakout by type of 

disturbance: wildfire, illegal dumping, unauthorized off-highway vehicle use, unauthorized 

campsites, noxious weed incursion, etc.

Acres of land treated to restore creosote-bursage 

vegetation in the ACEC (treated, but has not 

reached a condition to be considered restored).

Task 2.1 : Secure locally appropriate native seed needed for 

restoration work.

This is a critical task. Using locally sourced seed is the best way to 

preserve the genetic integrity of existing native plant communities 

and ensure the best restoration outcome. Preventing genetic erosion 

and preserving population genetics is one of the best ways to maintain 

ecosystem resilience from disturbance and adaptation to climate 

change. 

Quantity of native seed collected, purchased, and 

stockpiled.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 33

Mitigation Goals and Tasks Reason Why Mitigation Funds May Be Needed Measurable Objectives Indicators

Action Item 2.1.1: Collect 

wildland seed.

This action item is critical to Task 2.1: Collecting and stockpiling 

modest amounts of native seed each year is the best way to ensure a 

stable supply of seed for restoration and fire rehabilitation. Under cold 

storage, the seed of many Mojave Desert species can remain viable for 

decades. The BLM recently completed construction of a regional native 

seed warehouse for this purpose. 

Increase amount of native 

seed locally collected and 

stored.

Quantity of native seed collected and stockpiled.

Action Item 2.1.2: Collect an 

increased amount of seed by 

contracting with a commercial 

vendor.

This action item is critical to Task 2.1.1: Native forbs are extremely 

important for general wildlife, forage for desert tortoise, supporting 

native pollinator populations, and ecosystem function. It is not possible and too expensive to collect most native forbs in the quantities 

needed for restoration. Contracting with a commercial vendor to 

increase seed from wild collections and stockpile it, is the best way to 

ensure its availability for the restoration and rehabilitation work. 

Increase amount of native 

seed purchased.

Quantity of native forb seed purchased.

Quantity of purchased native forb seed 

stockpiled.

Task 2.2: Restore closed roads.

The decommissioning and restoration of closed roads meets the 

regional mitigation needs for impacts to vegetation and ecosystem 

services described in Goal 2. Closing and rehabilitating roads, by first 

decompacting soils followed by seeding native species, is an important 

way to restore landscape connectivity to native plant communities, 

reduce edge effect, and increase ecosystem resistance to colonization 

by nonnative weeds.

Reduce the acreage of 

closed roads by increasing 

the acreage of closed 

roads treated to restore 

native vegetation.

Miles and acres of closed and untreated roads in 

the Gold Butte ACEC (measured annually).

Miles and acres of treated roads (treated, but 

has not reached a condition to be considered 

restored).

Miles and acres of restored roads in the ACEC. 

Task 2.3: Restore new burns 

and old burn scars.

Reseeding burn scars is an important way to speed up long recovery 

times. Historically, large wildfires did not occur in the Mojave Desert; 

the Mojave is not adapted to fire and is very slow to recover from it. 

Postfire seeding with native species is one way to increase recovery of 

burned creosote-bursage vegetation. 

Decrease acreage of burn 

scars. Conduct postfire 

seeding with native 

species immediately.

Acres of disturbed and untreated land in the 

Gold Butte ACEC (measured annually) that were 

disturbed by fire. 

Acres of treated land in the ACEC (treated, but 

has not reached a condition to be considered 

restored). Breakout by type of treatment.

For new fires, number of days after the fire that 

seeding occurred.

Task 2.4: To the extent practicable, salvage and re-inoculate 

cryptobiotic crusts of disturbed 

sites to improve soils condition 

on restoration sites.

On small-scale restoration sites, it is possible to salvage and 

re-inoculate disturbed areas in order to facilitate recovery. This action 

directly improves soil resources as a regional mitigation for impacts to 

cryptobiotic soil crusts within the Dry Lake Solar Energy Zone. 

Improve soil condition of 

restoration sites.

Amount of Dry Lake Solar Energy Zone soil that 

is salvaged.

Number and size (acres) of sites re-inoculated 

with salvaged soils.

The mitigation activities 

described in Section 2.8 represent 

only a part of the funding required 

to manage the Gold Butte ACEC. 

Further, achieving these mitigation 

activities will take more funding 

than could be accomplished by the 

regional mitigation fees generated 

by leasing the Dry Lake SEZ. In 

order to achieve the mitigation 

objectives, ensure their durability, 

and otherwise manage the resource 

values in the Gold Butte ACEC, the 

BLM would “pool” funding from 

several potential sources, including, 

but not limited to:

•	 Funding appropriated by

Congress for management of the 

Gold Butte ACEC.

•	 Funding collected under the

“Final Clark County Multiple 

Species Habitat Conservation 

Plan and Environmental Impact 

Statement for Issuance of a 

Permit to Allow Incidental Take 

of 79 Species in Clark County, 

Nevada” and allocated to the 

BLM for use in the Gold Butte 

ACEC.

•	 Funding derived by land

sales conducted under the 

Southern Nevada Public Land 

Management Act and allocated 

to the BLM for conservation 

initiatives and/or capital 

improvements in the Gold Butte 

ACEC.

•	 Mitigation fees collected for

other land-disturbing activities.

Generally, the regional 

mitigation goals, tasks, and actions 

described in Table 2-6 are listed in 

the order they are recommended 

to occur as funding becomes 

available. The logic in this sequence 

is to secure the enforcement 

infrastructure to prevent further 

disturbance and ensure durability 

before undertaking restoration 

activities.
34 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Table 2-6. Priority/order of Gold Butte Area of Critical Environmental Concern mitigation goals and objectives. 

Goal Task Action 

Item Description Priority/Order

1 Prevent further degradation of the ACEC, and ensure the durability of the conservation investment in the Gold Butte ACEC. 

1 Augment law enforcement. 1

2 Monitor and treat (with signs, fencing, restoration, etc.) anthropogenic impacts (such as off-highway vehicle incursions, dump sites, 

campsites, and target shooting areas). 2

3 Monitor and treat noxious weeds. 3

4 Implement, monitor, and maintain fuel breaks. 4

2 Restore creosote-bursage vegetation and the ecosystem services it provides on closed roads, burn scars, and other anthropogenic

disturbances within the Gold Butte ACEC. 

1 Secure locally appropriate native seed needed for restoration work. 5

1 Collect wildland seed. 6

2 Collect an increased amount of seed by contracting with a commercial vendor. 7

2 Restore closed roads. 8

3 Restore new burns and old burn scars. 9

4 To the extent practicable, salvage and re-inoculate cryptobiotic crusts of disturbed sites to improve soils condition on restoration sites. simultaneous 

with 8 and 9
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 35

2.9 Mitigation Effectiveness Monitoring

and Adaptive Management Plan

n the Final Solar PEIS, the BLM 

committed to developing and 

incorporating a monitoring 

and adaptive management 

plan into its solar energy program. 

The BLM “Assessment, Inventory, 

and Monitoring Strategy for 

Integrated Renewable Resources 

Management” (AIM Strategy) 

(Toevs et al. 2011) will guide 

the development of a Dry Lake 

monitoring plan that will inform 

management questions at multiple 

scales of inquiry (e.g., the land use 

plan area, mitigation area, project 

area, and treatment). Detailed 

information about how the AIM 

Strategy will be implemented to 

support long-term monitoring of 

solar development is provided in 

Appendix A, Section A.2.4 of the 

Final Solar PEIS. This monitoring 

plan will also be consistent with 

and complement the BLM regional 

and national monitoring activities. 

In the context of solar 

energy development, long-term 

monitoring should be conducted 

to (1) evaluate the effectiveness 

of mitigation measures, including 

avoidance measures, onsite 

mitigation, and regional mitigation; 

(2) detect unanticipated direct and 

cumulative impacts at the project 

and regional level; and (3) evaluate 

the effectiveness of elements of 

the BLM’s solar energy program 

(e.g., policies, design features). To 

ensure that investments in regional 

mitigation actions are effective 

and that regional mitigation 

goals and objectives are being 

met, it is critical that the longterm monitoring plan include 

monitoring objectives specific to 

the regional mitigation locations 

and actions. The findings of the 

long-term monitoring activities 

will be examined by the BLM to 

support adaptive management of 

solar development (i.e., to identify 

the need to adjust operational 

parameters, modify mitigation 

measures, and/or implement new 

mitigation to prevent or minimize 

further impacts). The following 

steps will be conducted to develop 

the mitigation effectiveness 

monitoring plan for the Dry Lake 

SEZ:

Step 1. Developed Management 

Questions and Monitoring Goals.

The BLM interdisciplinary team 

developed management questions 

to articulate the issues of concern 

related to monitoring mitigation 

effectiveness. The management 

questions provide the basis for 

developing monitoring goals. 

The management questions and 

monitoring goals for the Dry Lake 

SEZ are provided in the two text 

boxes that follow.

I

Management Questions Established for

the Dry Lake Solar Regional Mitigation Strategy

1. Were the design features of the solar development effective to contain the impact of solar installation to the project site (e.g., trend of 

attributes, special status species habitat indicators, invasive species, habitat metrics)?

2. Are the avoidance areas maintaining ecological composition and process similar to those adjacent to the project area?

3. Did the regional mitigation actions achieve their objectives?

4. Were the Dry Lake Solar Energy Zone (SEZ) mitigation actions, collectively, effective in improving the trend of rangeland health attributes 

and landscape metrics in the regional mitigation site(s)?

5. What is the status and trend of rangeland health attributes for critical ecological processes necessary to sustain the Mojave Desert 

ecosystem at three scales: the Dry Lake SEZ 2-mile buffer area, the mitigation area(s), and the Mojave Basin and Range ecoregion? (Note: 

Some impacts may need to be assessed at different distances (e.g., watershed, airshed).)
36 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Monitoring Goals Established for

the Dry Lake Solar Regional Mitigation Strategy

1. Establish baseline measurements of rangeland health and landscape pattern. 

2. Determine the status, condition, and trend of priority resources, rangeland health attributes, and landscape pattern metrics once the 

permitted activity and related mitigation actions have been implemented.

3. Leverage the quantitative data from goals 1 and 2 to map the location, amount, and spatial pattern of priority resources and disturbances.

4. Generate quantitative and spatial data to address goals 1 and 2 and to contribute to existing land health assessment and evaluation 

processes at multiple scales of inquiry.

5. Generate quantitative and spatial data to determine if management actions (e.g., stipulations, land treatments) are moving resources 

toward desired states, conditions, or specific resource objectives identified in planning or related documents or legal mandates.

6. Use the collected data to validate and refine the conceptual understanding of key ecosystem components, processes, and sustainability 

concepts for the Mojave Basin and Range ecoregion and the Dry Lake SEZ.

Step 2. Identify Measureable 

Monitoring Objectives and 

Indicators. 

Measureable monitoring 

objectives will be established for 

each monitoring goal identified 

in Step 1. Objective setting will 

be based on current regulatory 

requirements, RMP goals, or 

the desired future condition 

consistent with the land potential 

(as described in the ecological 

site description, if available – see 

Step 4). Examples of measureable 

monitoring objectives are provided 

in the text box titled Measureable 

Monitoring Objective Examples.

Measureable Monitoring Objective Examples

An example of a measureable objective for land status/trend of vegetation is: 

(1) Detect a difference of 10 percentage points in the average amount of bare ground in the <MITIGATION LOCATION> over a 5-year period 

with 90% confidence.

(2) Determine whether cover of perennial grasses in the <MITIGATION LOCATION> is at least 25% with 90% confidence. 

An example of an objective for special status species is:

(1) Ensure that populations of <SPECIAL STATUS SPECIES NAME> in the <ECOREGION NAME> have not decreased by more than 20% within 

5 years of the solar installation with 95% confidence.

Objective setting includes 

specifying the attribute and 

measurable indicators of those 

attributes to be monitored. 

Monitoring objectives will indicate 

the desired amount of change 

(specific), level of confidence for the 

measured change (measurable), 

funding and capacity requirements 

(achievable), relationship to the 

management question (relevant), 

and timeframe during which the 

measurement occurs to effectively 

inform management (time 

sensitive).

Indicator selection will start 

with the standard AIM core and 

contingent quantitative indicators 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 37

(MacKinnon et al. 2011) and 

supplement with additional 

indicators derived from ecosystem 

conceptual models and/or linked 

to specific management questions. 

The AIM core indicators and 

methods provide high-quality, 

quantitative information on all 

land cover types the BLM manages 

(MacKinnon et al. 2011). Table 2-7 

(reproduced from MacKinnon et 

al. (2011)) lists each method and 

the corresponding indicators it 

measures, and the table describes 

recommendations to achieve 

consistent implementation across 

the BLM. When an ecological site at 

a monitoring location is identified, 

the BLM core measurements 

can be assessed in concert with 

information contained in the 

ecological site descriptions and the 

accompanying state and transition 

model to ascertain departure 

from an expected reference 

condition. The methodology 

for this assessment is contained 

in “Interpreting Indicators of 

Rangeland Health,” BLM Technical 

Reference 1734-6. Table 2-8 is a 

summary table from this technical 

reference. 

Table 2-7. Recommended methods and measurements for core and contingent indicators (reproduced from MacKinnon et al. (2011)).

Method Indicator(s) Description

For core indicators

Line-point intercept with 

plot-level species inventory

• Bare ground

• Vegetation composition

• Nonnative invasive species

• Plant species of management 

concern

Line-point intercept (LPI) is a rapid and accurate method for quantifying cover of vegetation and bare 

ground. Because LPI can underestimate cover of uncommon species, this method is supplemented with 

searches of a 150-ft (45.7-m) diameter standard plot for at least 15 minutes and until new species 

detections are more than 2 minutes apart. When performing LPI within tree cover, a modified pin method 

(e.g., a pivot-table laser or extendable pin) will be used to capture overstory cover.

Vegetation height measurement • Vegetation height

Measure height of tallest leaf or stem of woody and herbaceous vegetation (living or dead) within a 6-in 

(15-cm) radius recorded for points along a transect. If vegetation is taller than 10 ft, a standard tape and 

clinometer method should be used to estimate vegetation height.

Canopy gap intercept • Proportion of soil surface in large 

intercanopy gaps

Canopy gap intercept measures the proportion of a line covered by large gaps between plant canopies and is 

an important indicator of the potential for erosion. Use 1-ft (30-cm) minimum gaps.

For contingent indicators

Soil stability test • Soil aggregate stability This test measures the soil’s stability when exposed to rapid wetting and provides information on integrity of 

soil aggregates, degree of structural development, resistance to erosion, and soil biotic integrity.

Soil sample collection and 

analysis

• Significant accumulation of soil 

toxins

The presence and concentrations of toxins are assessed by collecting three samples from the soil surface and 

one sample at depths of 0 to 4 in (0 to 10 cm) and 4 to 8 in (10 to 20 cm) using a soil corer and following 

Forest Inventory and Analysis protocol.
38 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Table 2-8. Quantitative indicators and measurements relevant to each of the three rangeland health attributes (reproduced from Pellant et al. (2005)). 

Attribute Qualitative Assessment Indicator Quantitative

Measurement Method Key Quantitative Assessment Indicator

Soil/site stability

• Rills

• Water flow patterns

• Pedestals and/or terracettes

• Bare ground

• Gullies

• Wind-scoured, blowout, and/or depositional areas

• Litter movement

• Soil surface resistance to erosion

• Soil surface loss or degradation

• Compaction layer

Line-point intercept Bare ground

Canopy gap intercept Proportion of soil surface covered by canopy gaps longer than a 

defined minimum

Soil stability test Soil macro-aggregate stability in water

Hydrologic function

• Rills

• Water flow patterns

• Pedestals and/or terracettes

• Bare ground

• Gullies

• Soil surface resistance to erosion

• Soil surface loss or degradation

• Plant community composition and distribution

relative to infiltration and runoff

• Compaction layer

• Litter amount

Line-point intercept Bare ground

Canopy gap intercept Proportion of soil surface covered by canopy gaps longer than a 

defined minimum

Soil stability test Soil macro-aggregate stability in water

Biotic integrity

• Soil surface resistance to erosion

• Soil surface loss or degradation

• Compaction layer

• Functional/structural groups

• Plant mortality/decadence

• Litter amount

• Annual production

• Invasive plants

• Reproductive capability of perennial plants

Soil stability test Soil macro-aggregate stability in water

Line-point intercept Plant canopy (foliar) cover by functional group

Line-point intercept Plant basal cover by functional group

Line-point intercept Litter cover

Line-point intercept Invasive plant cover

In addition to the BLM 

core indicators, the BLM will 

consider requiring dust and 

noise monitoring as a leasing 

stipulation for the Dry Lake SEZ. 

The developer’s proposal will be 

reviewed by the BLM monitoring 

team to evaluate the efficacy of the 

proposal in complying with permit 

stipulations and informing BLM 

regulatory and land management 

needs. 

Special Status Plant Species 

Monitoring. The BLM will consider 

requiring the developer to fund 

the seed collection and long-term 

storage of any special status species 

plant population found on the 

project site and to conduct longterm monitoring on populations 

found on the project site and 

located in the same geographic 

region for the length of the 

duration of the impact. A special 

status plant species monitoring 

plan will be designed to determine 

the status, trend, and recruitment 

success of the populations and 

will follow methods described in 

BLM Technical Reference 1730-1, 

“Measuring and Monitoring Plant 

Populations” (Elzinga, Salzer, and 

Willoughby 1998).

Step 3. Develop Sampling 

Schema. 

Based on the management 

questions, monitoring goals, 

measurable objectives, and the 

indicators developed in Steps 1 

and 2, the BLM interdisciplinary 

team will determine the temporal 

and spatial scale of data collection 

activities. To develop the sampling 

schema, the following work will be 

conducted: 

Develop a Statistically Valid 

and Scalable Sampling Design.

Ecological sites are areas of land 

with the potential to produce 

similar types and amounts of 

vegetation based on soils and 

climate, and ecological sites are 

the basic units for stratifying 

landscapes for BLM monitoring 

activities. Because ecological site 

descriptions describe the ecological 

states (plant communities) 

that can occur in an ecological 

site and can provide expected 

indicator values for reference 

states, they are the foundation 

upon which BLM monitoring data 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 39

are evaluated. These data are 

also fundamental for terrestrial 

upland land health standards and 

land health evaluations. Where 

ecological site descriptions have 

not been developed, land potential 

metrics can be developed using a 

combination of field and remote 

sensing data to describe current 

and potential future conditions at 

broad scales. 

Incorporate Status and Trend 

Monitoring. The monitoring 

locations are determined through a 

statistically based (i.e., randomized) 

selection of monitoring sites. 

Once the monitoring extent 

(i.e., inference area) is determined 

for each scale, a stratified random 

technique will be used to select 

monitoring sites such that every 

location within the monitoring 

extent has a known and nonzero 

probability of being selected for 

sampling. Strata will be based on 

ecological sites (or groupings of 

similar ecological sites) to allow 

for adequate representation of all 

ecological sites and linear features 

(e.g., ephemeral washes). See Figure 

2-11 for the sampling schema of the 

Dry Lake SEZ and the 2-mile buffer 

area. The allocation of sample sites 

in the monitoring inference area 

is determined by the relative area 

of the stratum with a minimum 

of three monitoring locations per 

stratum. Sample sufficiency analysis 

will be completed for each stratum 

after the first season of sampling 

to determine if more monitoring 

locations are needed in a stratum.

Incorporate Monitoring 

of Effectiveness of Actions.

The sampling schema for an 

implementation action follows 

the criterion from the previous 

paragraph, with the sample 

population based on the geospatial 

footprint of the project area and 

the addition of control sites to 

determine effectiveness of the 

action. Control sites are chosen 

outside of the action area based 

on similarity of soils and existing 

vegetation community in the action 

area. Control sites can be a selection 

from existing statistically valid 

monitoring efforts such as the longterm monitoring sites that are a part 

of the BLM Landscape Monitoring 

Framework. An example of BLM 

Landscape Monitoring Framework 

monitoring sites is represented in 

Figure 2-12 for the Gold Butte ACEC, 

which is one of the potential solar 

regional mitigation areas in the Dry 

Lake SRMS.

To account for the variability 

among sites of similar potential, 

a minimum of three control sites 

are selected for each strata present 

in the treatment area. Sample 

sufficiency analysis should be 

conducted after the first year of 

sampling to examine indicator 

variability within each stratum to 

determine if additional sites are 

needed in the implementation 

action or control areas. 

Integrate Remote Sensing 

Monitoring Technologies. 

Considerable work has been done 

to develop methodologies for 

processing and analyzing remote 

sensing data in order to extract 

information suitable for assessing 

changes in certain environmental 

conditions over time. The AIM 

Strategy emphasizes the value 

of integrating remote sensing 

technologies into long-term 

monitoring programs, wherever 

feasible, in order to provide costeffective methods for collecting 

data and analyzing effects (Toevs et 

al. 2011). 
40 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Figure 2-11. Example of a stratified, nonbiased sampling schema for the Dry Lake Solar Energy Zone.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 41

Remote sensing technologies 

provide several benefits. They 

support the collection of spatially 

comprehensive datasets that are 

not otherwise readily available. In 

addition, the collection of data from 

a satellite or aircraft is nonintrusive, 

a very valuable feature for assessing 

ecologically and culturally sensitive 

areas. Semiautomated data 

processing of remotely sensed 

images can be a cost-effective 

way to reliably detect and identify 

features and quantify parameters 

over large areas more frequently. 

This feature is desirable for 

monitoring spatially heterogeneous 

and temporally dynamic arid and 

semiarid environments. Historic 

archives of remotely sensed data 

permit retrospective assessments 

and are thus suitable for long-term 

monitoring (Washington-Allen et al. 

2006).

Figure 2-12. Example of a stratified, nonbiased sampling schema for the Gold Butte Area of Critical Environmental Concern.
42 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

The limitations of 

remote sensing are that such 

measurements are indirect, and 

the spatial sampling unit (i.e., pixel) 

is arbitrary. In remote sensing, 

spectral reflectance signals from 

elements on the ground are 

assumed to be isolated from 

environmental and instrumental 

noise (Stow 1995). Further, targets 

are assumed to be spectrally 

separable from background, and 

different target types are assumed 

to have unique spectral signatures 

(Friedl, McGwire, and McIver 2001). 

The BLM interdisciplinary team 

should consult the AIM Strategy 

guidance and remote sensing 

experts to investigate cost-effective 

ways to incorporate the use of 

remote sensing technologies 

into the monitoring of mitigation 

actions.

Step 4. Develop Analysis and 

Reporting System. 

Interpreting the data to 

determine the status, departure, or 

rate of change requires comparison 

of data collected via field sampling 

and/or remote sensing against 

indicators of ecological attributes 

for reference conditions. These 

reference conditions will be based 

on site or landscape potential 

which is described in ecological 

site descriptions. Ecological sites 

are the basis for the monitoring 

schema because they react similarly 

to factors like disturbance or 

degradation (historic or current), 

which can lead to alternative 

stable plant communities outside 

the historic potential of the site. 

For this reason, ecological sites 

are a basic unit for analysis and 

reporting. Elements of an ecological 

site description that are helpful 

for defining reference conditions 

and interpreting departure from 

reference conditions include: stateand-transition conceptual models 

of plant community changes 

in response to disturbance or 

management; descriptions of the 

range of plant communities that 

could exist on the site in addition 

to the potential vegetation; 

descriptions of anthropogenic 

and natural disturbances and their 

potential to cause changes in 

plant communities; descriptions 

of dynamic soil properties (e.g., 

organic matter content, soil 

aggregate stability); and amount of 

bare ground. 

Step 5. Define Adaptive 

Management Approach. 

The BLM will use information 

derived from the Dry Lake 

monitoring plan to determine if 

resource management objectives 

described in the Las Vegas RMP—

the Dry Lake SEZ, the 2-mile buffer 

zone around the Dry Lake SEZ, 

and the areas where regional 

mitigation actions will occur—are 

being met. If the objectives are 

not being met, the monitoring 

program information will be used 

to make necessary management 

adjustments to the mitigation 

actions. Reporting at multiple scales 

will inform decisionmakers on the 

effectiveness of management and 

mitigation actions, opportunities 

for adaptive management (e.g., 

adjusting operational parameters, 

modifying mitigation actions, and/

or adding new mitigation actions), 

refinement of conceptual models, 

and evaluation of the monitoring 

program itself. Adaptive changes 

will be subject to environmental 

analysis, land use planning, and 

public involvement, as appropriate.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 43

2.10 Implementation Strategy

his project considered 

impacts that are likely 

to occur with the full 

build-out of the Dry Lake 

SEZ identified in the Final Solar 

PEIS. The project team found that 

while the potential for avoiding 

and/or mitigating many of the 

impacts onsite is good, the 

following impacts are likely to be 

unavoidable:

•	 The loss of desert tortoise

habitat and the potential loss 

of individual desert tortoises. 

The desert tortoise is listed as 

a threatened species under the 

Endangered Species Act. 

•	 The loss of habitat and the

potential loss of individual 

animals for the following 

BLM special status species: 

Gila monster, Mojave Desert 

sidewinder, ferruginous hawk, 

golden eagle, loggerhead shrike, 

and Le Conte’s thrasher. 

•	 The loss of rosy two-toned

penstemon habitat and the 

potential loss of individual 

plants. The rosy two-toned 

penstemon is a BLM special 

status species plant.

•	 The loss of ecosystem services

and the human uses depending 

on them, as a result of 

development and until the lease 

expires and the site is restored. 

The primary components of 

an ecological system are: soils, 

vegetation, water, air, and 

wildlife. 

•	 The visual impacts that will occur

will exceed allowable levels in an 

area designated as VRM Class II 

in the Las Vegas RMP (BLM 1998).

In addition, the following 

unavoidable impacts were 

identified as having the potential 

to occur, depending on the way 

the area is developed, the success 

of onsite mitigation activities, 

data gaps, and/or the discovery of 

unanticipated resources:

•	 Introduction and spread of

invasive/noxious weeds.

•	 Alterations to surface hydrology.

•	 Loss of cultural resources.

•	 Increased density of desert

tortoise in the Coyote Springs 

ACEC (which was established for 

tortoise recovery).

•	 Visual resources as seen from

nearby specially designated 

areas.

•	 Certain Native American

concerns (e.g., loss of habitat and 

spiritual values).

Accordingly, and consistent 

with the management prescriptions 

for the affected resources in the 

Las Vegas RMP, the project team 

recommends the following regional 

mitigation goals:

•	 Sustain the populations of

federally listed species so they 

no longer need protection under 

the Endangered Species Act.

•	 Manage habitats for nonlisted

special status species to support 

viable populations so future 

listing is not necessary.

•	 Mitigate the loss of plants and

habitat for the rosy two-toned 

penstemon to support viable 

populations in which the SEZ is 

located so that future listing is 

not necessary.

•	 Restore and/or protect the

creosote-bursage vegetation 

community disrupted by 

development (taking into 

account the existing landscape 

condition in the SEZ).

•	 Restore and/or protect the

visual resource values altered 

by development of the SEZ 

(taking into account the existing 

condition of visual resource 

values in the Dry Lake SEZ).

To achieve these goals, 

the project team recommends 

mitigation actions be undertaken 

in the Gold Butte ACEC. The Gold 

Butte ACEC was established in the 

Las Vegas RMP (BLM 1998). It has an 

area of approximately 350,000 acres 

(1416 km2). The primary resource 

values listed in the RMP are:

•	 Cultural and historic resources.

•	 Scenic values.

•	 Wildlife habitat.

•	 Special status species habitat.

•	 Botanical resources.

T
44 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

The Gold Butte ACEC was 

selected from several potential 

regional mitigation candidate 

locations for the following reasons:

•	 The Mojave Basin and Range REA

(NatureServe 2013) suggests that 

creosote-bursage vegetation in 

the Gold Butte ACEC may persist 

longer under climate change 

than the other nominated 

ACECs. 

•	 Niche modeling, completed by

the National Park Service for the 

Lake Mead National Recreation 

Area, suggests, under future 

climate change, high-quality 

desert tortoise habitat will 

remain in the Gold Butte ACEC 

while most of the adjacent 

desert tortoise habitat in the 

national recreation area will 

decline and disappear.

•	 Road decommissioning and

restoration is proposed as a Dry 

Lake SEZ regional mitigation 

activity. The Gold Butte ACEC 

has already completed road 

designations. Road designations 

have not been completed on the 

other ACECs.

•	 Reseeding burn scars is

proposed as a Dry Lake SEZ 

regional mitigation activity. 

The Gold Butte ACEC suffered 

multiple wildfires in 2005 and 

2006 and could benefit from 

restoration. The other ACECs 

have had fewer fires.

•	 The Gold Butte ACEC is an

important landscape corridor 

between Lake Mead and the 

Virgin Mountains for game 

species managed by the Nevada 

Department of Wildlife. 

The recommended regional 

mitigation actions are as follows:

1. Prevent further degradation 

of the ACEC, and ensure the 

durability of the conservation 

investment by:

a. Augmenting BLM law 

enforcement capacity 

sufficient to maintain 

ranger patrols in the ACEC. 

b. Providing a monitor to track 

activities in and impacts to 

the ACEC.

c. Building the capacity to 

respond in a timely manner 

to activities that threaten 

resource values.

d. Providing treatment 

for noxious weeds and 

maintaining fuel breaks to 

protect the area. 

2. Restore creosote-bursage 

vegetation on closed roads, 

burn scars, and other 

anthropogenic impacts. 

Included in this goal is the 

procurement of genetically 

appropriate native seed to 

complete these restoration 

activities. 

Any authorized mitigation 

activities will likely occur over a 30-

year period, the expected lifetime 

of a solar facility lease in the Dry 

Lake SEZ. This extended time period 

is critical for implementation and 

to provide durability. Vegetation 

management in the Mojave Desert 

takes time; the conditions for seed 

germination and establishment 

typically occur once every 8 to 10 

years. It takes time to develop the 

capacity to build and maintain a 

restoration program; it can take 

up to 5 years to collect or procure 

the genetically appropriate native 

seed needed for restoration and 

rehabilitation. By implementing 

the mitigation over 30 years, funds 

can be used to prudently respond 

to current and future needs. The 

proposed mitigation location 

and actions will allow the BLM to 

provide for sustainable use by the 

public and conservation that will 

benefit future generations.

All of the recommended actions 

and the location are consistent 

with the current Las Vegas RMP. The 

Las Vegas RMP is currently being 

revised. It is recommended that the 

team developing the RMP revision 

consider incorporating a regionallevel strategy for mitigating the 

unavoidable and cumulative 

impacts that may occur as a result 

of land use authorizations executed 

under the revised RMP. 

In order to increase the 

probability of success in achieving 

and maintaining the mitigation 

goals and to facilitate effective 

adaptive management (including 

action to protect the resources 

identified as having the potential 

to be impacted), the project team 

recommends the development and 

implementation of a monitoring 

and adaptive management plan.

In order to fund the 

recommended mitigation 

actions, monitoring, and adaptive 

management, the project team 

recommends a regional mitigation 

fee be assessed to the developer(s) 

similar to the example provided 

in Section 2.6. This fee will be in 

addition to the Endangered Species 

Act Section 7 fee (currently $824/

acre). It is recommended that a 

third-party entity be retained to 

manage mitigation funds.

The findings and 

recommendations offered here 

are intended to inform the 

decisionmaking process associated 

with leasing land in the Dry 

Lake SEZ for utility-scale solar 

development. At the discretion of 

the BLM authorized officer, all or 

part of these recommendations 

could be included in the 

decisionmaking process.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 45

References

BLM (Bureau of Land Management). 

1998. Proposed Las Vegas 

Resource Management Plan 

and Final Environmental Impact 

Statement. Bureau of Land 

Management, Las Vegas Field 

Office, Las Vegas, NV.

BLM (Bureau of Land Management). 

2012. Approved Resource 

Management Plan 

Amendments/Record of 

Decision (ROD) for Solar 

Energy Development in Six 

Southwestern States. Bureau of 

Land Management. 

BLM (Bureau of Land Management). 

2013a. Best Management 

Practices for Reducing Visual 

Impacts of Renewable Energy 

Facilities on BLM-Administered 

Lands. Bureau of Land 

Management, Cheyenne, WY.

BLM (Bureau of Land Management). 

2013b. Interim Policy, Draft – 

“Regional Mitigation” Manual 

Section – 1794. Instruction 

Memorandum No. 2013-142. 

Bureau of Land Management, 

Washington, DC.

BLM (Bureau of Land Management). 

Forthcoming. Procedural 

Guidance for Developing Solar 

Regional Mitigation Strategies. 

Bureau of Land Management, 

Washington Office, Washington, 

DC.

BLM and DOE (Bureau of Land 

Management and U.S. 

Department of Energy). 

2012. Final Programmatic 

Environmental Impact 

Statement (PEIS) for Solar 

Energy Development in Six 

Southwestern States. FES 12-

24, DOE/EIS-0403. Bureau of 

Land Management and U.S. 

Department of Energy.

Brussard, P.F., K.H. Berry, M.E. Gilpin, 

E.R. Jacobson, D.J. Morafke, C.R. 

Schwalbe, C.R. Tracy, and F.C. 

Vasek. 1994. Desert Tortoise 

(Mojave Population) Recovery 

Plan. U.S. Fish and Wildlife 

Service, Portland, OR.

Elzinga, C.L., D.W. Salzer, and J.W. 

Willoughby. 1998. Measuring 

and Monitoring Plant 

Populations. Tech Ref 1730-1. 

Bureau of Land Management, 

National Business Center, 

Denver, CO. http://www.

blm.gov/nstc/library/pdf/

MeasAndMon.pdf. 

Friedl, M.A., K.C. McGwire, and D.K. 

McIver. 2001. An Overview of 

Uncertainty in Optical Remotely 

Sensed Data for Ecological 

Applications. p. 258-283. In: 

C.T. Hunsaker, M.F. Goodchild, 

M.A. Friedl, and T.J. Case (eds). 

Spatial Uncertainty in Ecology: 

Implications for Remote 

Sensing and GIS Applications, 

Springer, NY.

Hamilton, M.E., and S.R. Kokos. 

2011. Clark County Rare 

Plant Habitat Modeling. 

Environmental Planning Group, 

Inc., and Bureau of Reclamation. 

http://bit.ly/Qbm19H.

MacKinnon, W.C., J.W. Karl, G.R. 

Toevs, J.J. Taylor, M. Karl, C.S. 

Spurrier, and J.E. Herrick. 2011. 

BLM Core Terrestrial Indicators 

and Methods. Tech Note 440. 

Bureau of Land Management, 

National Operations Center, 

Denver, CO.

NatureServe. 2013. Mojave Basin 

and Range Rapid Ecoregional 

Assessment. http://www.blm.

gov/wo/st/en/prog/more/

Landscape_Approach/reas/

mojave.html#memo.

Pellant, M., P. Shaver, D.A. Pyke, and 

J.E. Herrick. 2005. Interpreting 

Indicators of Rangeland Health, 

Version 4. Tech Ref 1734-6. 

Bureau of Land Management, 

National Science and 

Technology Center, Denver, 

CO. http://www.blm.gov/nstc/

library/techref.htm.

SWCA and University of Arizona 

(SWCA Environmental 

Consultants and Bureau 

of Applied Research in 

Anthropology). 2011. 

Ethnographic and Class I 

Records Searches for Proposed 

Solar Energy Zones in California, 

Nevada, and Utah for the 

Bureau of Land Management’s 

Solar Programmatic 

Environmental Impact 

Statement. SWCA Project No. 

16983. SWCA Environmental 

Consultants and University of 

Arizona, Albuquerque, NM.

Stow, D.A. 2005. Monitoring 

Ecosystem Response to Global 

Change: Multitemporal Remote 

Sensing Analysis. p. 254-286. In: 

J.M. Moreno et al. (eds). Global 

Change and MediterraneanType Ecosystems. SpringerVerlag New York, Inc.

Toevs, G.R., J.J. Taylor, C.S. Spurrier, 

W.C. MacKinnon, and M.R. Bobo. 

2011. Assessment, Inventory, 

and Monitoring Strategy 

for Integrated Renewable 

Resources Management. Bureau 

of Land Management, National 

Operations Center, Denver, CO.

Washington-Allen, R.A., N.E. 

West, R.D. Ramsey, and R.A. 

Efroymson. 2006. A Protocol for 

Retrospective Remote SensingBased Ecological Monitoring of 

Rangelands. Rangeland Ecology 

and Management 59 (1): 19-29.
46 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Appendix A:

Impact Assessment Summary Table

The following table summarizes the Bureau of Land Management and Argonne 

National Laboratory subject matter expert responses to the process steps and criteria 

used to identify the unavoidable impacts that are likely to occur as a result of solar 

development in the Dry Lake Solar Energy Zone. The process steps and criteria for 

identifying unavoidable impacts are outlined in Section 2.4.3.1 of this document.

Dry Lake Solar Energy Zone: Potential Unavoidable Impact Summary 

Resource/ 

Issue

Are impacts 

comprehensive and 

accurate?

Do impacts 

need to be 

amended?

Any 

additional 

design 

features?

To what degree are impacts likely to be 

mitigated onsite?

Are impacts 

likely to be 

adequately 

mitigated?

Justification for impacts being or not 

being mitigated onsite:

Soils/Erosion Yes No No

Little can be done onsite to mitigate the loss of up to 

5,717acres of soil. Avoidance (not developing some 

areas) will reduce the acreage, and soil stabilization 

measures can reduce soil erosion post disturbance. 

No

The degree of disturbance required will result 

in the loss of a significant quantity of biological 

soils. While predicted recovery rates for biological soil crusts vary from study to study, most put 

the recovery rate for damaged crust between 

20 to 250 years, once disturbance is removed. 

For desert pavement, natural recovery rates are 

in the millennia, and large-scale disturbances 

are not thought to be recoverable.

Wildlife Yes No No

Little can be done onsite to mitigate the loss of up 

to 5,717acres of general wildlife habitat. Avoidance 

(such as not developing riparian areas or under 

existing power lines) will reduce the acreage.

No Development of the Dry Lake SEZ will likely 

impact up to 5,717 acres of wildlife habitat.

Special

Status 

Species - 

Animals

Yes (The PEIS 

list of species 

potentially 

occurring in 

the SEZ has 

been modified on the 

basis of BLM 

local data; 

predisturbance 

surveys to confirm absence 

of species 

potentially 

present but 

not further 

evaluated 

under the 

SRMP may be 

required of 

developers. 

If found, 

the need 

for regional 

mitigation 

of impacts to 

those species 

would be 

addressed at 

that time.) 

No No

Onsite mitigation will reduce, but will not eliminate, 

the loss of special status animal species and their 

habitat. Development of the Dry Lake SEZ would 

result in loss of individuals and/or habitat of six 

special status animal species (listed in the far right 

column) as well as the federally threatened desert 

tortoise and migratory bird species protected under 

the Migratory Bird Treaty Act. Since birds are highly 

mobile, they will most likely move out of harm’s 

way during construction, except during breeding 

season. Effects to individual migratory birds and bird 

nests can be avoided by not constructing during the 

breeding season (March 1- August 31). If construction takes place during the breeding season, nest 

surveys will be conducted. If bird nests are found, 

then an appropriately sized buffer will be placed 

around the nest. No construction will be allowed 

within the buffer, until the birds have fledged. 

Although individual golden eagles and their nests 

will not be directly affected, construction will affect 

golden eagle foraging habitat. Reptiles tend to take 

shelter in burrows and do not move out of harm’s 

way. Individual reptiles can be killed or maimed 

during construction. Desert tortoise minimization 

measures include: translocation/relocation, project 

fencing, education programs, perch deterrents, trash 

program, authorized biologists/monitors onsite 

during construction, clearance surveys, educational 

signs, minimizing ground disturbance, no pooling 

of water (dust control), and covering holes and 

trenches when not in use.

No

Six BLM sensitive species are known to occur or 

likely to occur in the SEZ (Gila monster, Mojave 

Desert sidewinder, ferruginous hawk, golden 

eagle, loggerhead shrike, and Le Conte’s thrasher), as well as the federally threatened desert 

tortoise and migratory bird species protected 

under the Migratory Bird Treaty Act. All would 

suffer unavoidable impacts. Complete build-out 

of the Dry Lake SEZ would directly impact up to 

5,717 acres.

In the context of the National Environmental 

Policy Act, direct impacts on the overall range 

of these species would not be significant 

because the Dry Lake SEZ is only a small portion 

of the overall range (see Final PEIS for specific 

percentages). However, when combined with 

other BLM lands actions (including other 

renewable energy development projects, utility 

corridors and land disposal), multiple use 

activities (including mining and off-highway 

vehicle recreation), and threats (fragmentation, 

increased competition with invasive species), 

development of the Dry Lake SEZ could cause 

continued population declines of the above 

mentioned species.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 47

Resource/ 

Issue

Are impacts 

comprehensive and 

accurate?

Do impacts 

need to be 

amended?

Any 

additional 

design 

features?

To what degree are impacts likely to be 

mitigated onsite?

Are impacts 

likely to be 

adequately 

mitigated?

Justification for impacts being or not 

being mitigated onsite:

Vegetation Yes No No

Little can be done onsite to mitigate the loss of 

up to 5,717acres of vegetation. While the native 

vegetation on a small portion of the disturbed areas 

could be restored, the Mojave Desert is extremely 

slow to recover from disturbance. Estimates suggest 

that, without active restoration, it takes the Mojave 

Desert 76 years for reestablishment of perennial 

plant cover and 215 years for reestablishment 

of both perennial and annual species cover. This 

means the cumulative impacts of ground-disturbing 

activities are additive over time. It also means 

the BLM can use restoration as a way to mitigate 

cumulative impacts because restoration can speed 

up recovery time.

No

Development of the Dry Lake SEZ would result 

in the direct loss of up to 5,717 acres of Mojave 

creosote-bursage scrub, saltbush scrub, and 

mesquite-acacia woodland. These native plant 

communities, along with the intact biological 

soil crusts and desert pavement within them, 

provide ecosystem services including: stabilizing soils against wind and water erosion; 

maintaining air and water quality; maintaining 

nutrient cycling; maintaining landscape connectivity including the dispersal and migration 

of species across the landscape; protecting 

against colonization by nonnative weeds and 

protecting against wildfire; and providing 

shelter and forage for game species, migratory 

birds, six BLM special status animal species, 

and general wildlife species. Development 

would result in direct removal or disturbance 

of these native plant communities, special soil 

environments, and the ecosystem services they 

provide. The direct impacts would probably not 

be significant in the sense of NEPA; however, 

on a larger scale the cumulative loss of these 

services could cost the public in terms of 

reduced environmental quality and cost BLM 

funding if it becomes necessary to implement 

management actions to compensate for their 

disruption or loss.

Special

Status 

Species - 

Vegetation

Yes Yes1 No

Little can be done onsite to mitigate the loss of 

the one special status plant species known to exist 

in the Dry Lake SEZ. Development of the Dry Lake 

SEZ would result in the removal of rosy two-toned 

penstemon plants and the alteration of 5,717 acres 

of habitat. Given low population densities and 

dispersed distribution of the species across the 

SEZ, avoidance of individual plants is not practical 

and would excessively fragment the remaining 

population.

No

One BLM special status plant species, the rosy 

two-toned penstemon (Penstemon bicolor

ssp. roseus) would suffer unavoidable impacts.

Visual 

Resources Yes No

Yes 

(managed 

development plan 

for the SEZ; 

coordination 

with City 

of North 

Las Vegas 

planners).

Part of the SEZ is currently managed as VRM Class 

III under the applicable BLM land use plan. Onsite 

mitigation will reduce, but will not eliminate, 

visual impacts to scenic values. The Final Solar PEIS 

identified moderate to strong visual contrasts in the 

following specially designated areas in the vicinity of 

the SEZ: Desert National Wildlife Refuge, Old Spanish 

National Historic Trail, Arrow Canyon Wilderness, 

Muddy Mountains Wilderness, and Nellis Dunes Special Recreation Management Area. Potential impact 

on night skies. Implementing design features, such 

as selecting paint colors that blend with the environment, minimizing vegetation removal, and using 

good lighting design and operating procedures, can 

reduce contrast.

No

Development of the Dry Lake SEZ would introduce changes in visual forms, lines, colors, and 

textures that would contrast strongly with the 

surrounding landscape in the SEZ, and because 

of the large size of the facilities and their highly 

reflective surfaces, the Dry Lake SEZ could be 

visible for long distances from surrounding 

lands. The SEZ is a flat area devoid of tall 

vegetation, and consequently, solar facilities 

within the SEZ generally could not be screened 

from view from nearby lands. While onsite mitigation would reduce visual contrasts caused by 

solar facilities within the SEZ, it would not likely 

reduce impacts to less than moderate or strong 

levels for nearby viewers.
48 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Resource/ 

Issue

Are impacts 

comprehensive and 

accurate?

Do impacts 

need to be 

amended?

Any 

additional 

design 

features?

To what degree are impacts likely to be 

mitigated onsite?

Are impacts 

likely to be 

adequately 

mitigated?

Justification for impacts being or not 

being mitigated onsite:

Specially 

Designated 

Areas

Yes No No

See the Hydrology section in this table. The Final 

Solar PEIS identified moderate to strong visual 

contrasts in the following specially designated areas 

in the vicinity of the SEZ: Desert National Wildlife 

Refuge, Old Spanish National Historic Trail, Arrow 

Canyon Wilderness, Muddy Mountains Wilderness, 

and Nellis Dunes Special Recreation Management 

Area.

Maybe for 

Coyote Springs 

ACEC but not 

for visual 

impacts at 

other specially 

designated 

areas.

It depends if impacts on hydrology extend to 

the Coyote Springs ACEC.

For visual impacts, full development of the SEZ 

with solar facilities would cause moderate to 

strong visual contrasts that could not be hidden 

from view from the specially designated areas.

Military Yes No No

The Air Force has stated that glare, thermal effects, 

structure height greater than 250 ft, lighting of 

structures, and transmission lines could adversely 

affect operations. Collision hazards can be reduced 

by restricting maximum development height. While 

the probability of flight crews parachuting into the 

area as a result of in-flight emergencies is low, the 

safety hazard posed by solar facilities cannot be 

completely mitigated onsite. 

No

Because the development area is under the 

approach and departure routes for military 

aircraft traveling between Nellis Air Force Base 

and the Nevada Test and Training Range, there 

is a heightened risk of emergencies occurring 

as aircraft pass over the site. Such emergencies 

can involve the jettisoning of ordnance, crews 

ejecting and parachuting, and aircraft crashing. 

Restriction on project height can reduce 

collision hazards. 

Native 

American 

Concerns

Yes No No See Hydrology and Wildlife sections in this table. No

Tribal representatives have identified impacts 

on hydrology and wildlife as concerns. The 

extent of the impacts on hydrology depends 

on the technology and on the cumulative use 

of water resources. Unavoidable impacts on 

wildlife habitat are expected. Loss of wildlife 

habitat can be mitigated to some extent onsite.

Invasive/

Noxious 

Weeds

Yes No No

The active and prolonged implementation of design 

features can greatly reduce, but not eliminate, the 

risk of the establishment and spread of invasive 

species.

Maybe

Onsite mitigation will reduce, but will not 

eliminate, the potential for invasive species. 

The degree of disturbance creates a significant 

opportunity for the establishment of invasive 

species and weeds.

Hydrology 

(Water/ 

Watershed/ 

Water 

Quality)

Yes No No

While it depends on the water demands of the 

development and whether the subsurface hydrology 

is affected, some impacts might be mitigated by the 

migration of water used for dust suppression and/or 

for cleaning mirrors back into the ground.

Maybe

The nature of the solar technology deployed 

will dictate water requirements. Onsite mitigation will reduce, but will not eliminate, the 

need for water. While the groundwater in the 

hydrologic basin is overallocated, it is currently 

not overused. If all allocations are fully used, 

the water used in solar operations, in conjunction with water used outside the SEZ, would 

contribute to a decline in the water table. 

Riparian Yes No No

Most impacts can be mitigated onsite by avoiding 

development in the washes and by the installation 

of engineering controls on surface water runoff/

erosion.

The riparian areas that occur within the SEZ are 

shallow ephemeral washes and have been excluded 

from the developable area. 

Maybe

It depends on the engineering controls. 

Development may alter ephemeral stream 

channels that can impact flooding and debris 

flows during storms, groundwater recharge, 

ecological habitats, and riparian vegetation 

communities. Reductions to the connectivity 

of these areas with existing surface waters and 

groundwater could limit water availability and 

thus alter the ability of the area to support vegetation and aquatic species. This could reduce 

overall stability of the natural landscape.

Cultural Yes No No

A preconstruction cultural survey and the programmatic agreement establishing a protocol for treating 

cultural resources if they are discovered during 

construction decrease the risk of disturbing or destroying cultural resources. The eligible Old Spanish 

Trail/Mormon Road linear feature can be avoided.

Maybe

The discovery of new cultural sites is always 

a possibility, and adequate mitigation would 

be dependent on the resources discovered and 

their relative significance in the region. 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 49

Resource/ 

Issue

Are impacts 

comprehensive and 

accurate?

Do impacts 

need to be 

amended?

Any 

additional 

design 

features?

To what degree are impacts likely to be 

mitigated onsite?

Are impacts 

likely to be 

adequately 

mitigated?

Justification for impacts being or not 

being mitigated onsite:

Acoustics Yes No No

Some temporary acoustic impacts are expected 

during construction. Onsite standards and monitoring are expected to keep impacts in an acceptable 

range.

Yes

The area is currently impacted by traffic noise 

from Interstate15 and Route 93 and the railroad 

adjacent to the site. Additional impacts from 

solar development are expected to be temporary, localized, and neither significantly louder 

than or out of character with current noise. 

Air Quality Yes No No

Some temporary impacts are expected during 

construction, primarily from construction vehicle 

emissions and from dust kicked up by construction 

vehicles and by wind blowing over disturbed crust. 

Onsite mitigation, such as dust suppression, and 

monitoring are expected to keep impacts in an 

acceptable range (less than the National Ambient 

Air Quality Standards for carbon monoxide and 

particulate matter). 

Yes

The area is currently impacted by emission 

from vehicles traveling on Interstate15 and 

Route 93, the Apex landfill, the mines and mills 

operating on the south end of the SEZ, and the 

natural gas-fired power plants operating on 

and around the SEZ. Additional impacts are expected to be temporary and are not expected to 

result in noncompliance with National Ambient 

Air Quality Standards. 

Environmental Justice Yes No No No adverse impacts are anticipated. Yes

While there are minority and/or low income 

populations within 50 miles, they are more 

than 10 miles away, and views of the SEZ are 

restricted.

Fire Yes No No

Onsite mitigation can significantly reduce the chances of a wildfire. Historically, the SEZ has seen very 

little fire disturbance. However, this may increase 

if burnable vegetation becomes established. Mitigation that reduces the establishment of burnable 

invasive species will maintain a low risk status. 

Onsite mitigation would include a requirement 

for the development and implementation of a fire 

safety and emergency response plan, including fuel 

inventory, to be developed and executed during construction and operations, including fire/fuel breaks 

and design features to help minimize risk.

Yes

The area is low fire risk to begin with. This 

would change only if burnable invasive species 

were allowed to establish.

Hazardous 

Waste Yes No No

Virtually all impacts can be mitigated onsite. The 

design features, which require development of an 

emergency response plan, will reduce the chances of 

a hazardous material release and provide a protocol 

for mitigating the site, should one occur. 

Yes

The implementation of design features for 

handling any hazardous substances will reduce 

the risk of exposure and/or release and, should 

one occur, specify the emergency procedures 

for protecting public safety and for remediating 

the site. 

Lands and 

Realty Yes No No

Virtually all impacts can be mitigated onsite. According to regulation, any and all solar development 

must occur in deference to all previously existing 

rights. In addition, the BLM Southern Nevada District 

Office has made the decision to remove from leasing 

the areas within the SEZ encumbered by existing 

rights-of-way (plus a 200-foot buffer). 

Yes

By regulation, any new activity must occur in 

deference to existing rights. Thus, potential 

impacts have been avoided.

Minerals Yes No No

Virtually all impacts can be mitigated onsite by 

avoiding existing mining and mill site claims. The 

Southern Nevada District Office has made the 

decision to remove from leasing the existing mining 

and mill site claims. 

Yes

By regulation, any new activity must occur in 

deference to existing rights. Thus, potential 

impacts have been avoided.

Paleontological Yes No No

No mitigation is required as no paleontological 

resources are known or are expected to exist in the 

SEZ. Design features will reduce the risk that any 

paleontological resources that are discovered will be 

destroyed.

Yes

Not applicable—there are no known paleontological resources on site, and the geology 

suggests the potential is low.

Livestock 

Grazing Yes No No No mitigation is necessary as there are no impacts. Yes Not applicable—there are no grazing allotments within the SEZ.
50 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Resource/ 

Issue

Are impacts 

comprehensive and 

accurate?

Do impacts 

need to be 

amended?

Any 

additional 

design 

features?

To what degree are impacts likely to be 

mitigated onsite?

Are impacts 

likely to be 

adequately 

mitigated?

Justification for impacts being or not 

being mitigated onsite:

Recreation 

(Includes 

Travel Management 

Areas)

Yes No No

Virtually all impacts on recreation can be mitigated 

onsite. The potential impacts are primarily related to 

providing access to Dry Lake and the Arrow Canyon 

mountain range to the west of the SEZ. Through a 

combination of avoidance, design features, and the 

establishment of alternative access routes to these 

areas, the potential impacts can be adequately 

mitigated onsite. 

Yes

Relatively little recreation currently occurs in 

the SEZ. Access to the Arrow Canyon Range and 

Dry Lake can be maintained by existing and/

or new routes. If new routes are established, 

a NEPA analysis would be required for those 

routes.

Socioeconomic Yes No No

Possible adverse impacts of in-migrating workers 

required for project construction and operation (e.g., 

hiring of police, fire fighters, and teachers and providing services to new area workers and families). 

Onsite mitigation could include requiring developers 

to secure agreements for local government services 

as a condition of a “Notice to Proceed.”

Yes

Any adverse impacts caused by the requirement 

for local government services would be mitigated by the requirement for the developer to 

secure agreements as a condition of the “Notice 

to Proceed.”

Transportation Yes No No

Virtually all impacts on transportation can be 

mitigated onsite. The potential impacts are primarily 

related to providing access to Dry Lake and the 

Arrow Canyon Range to the west of the SEZ. Through 

a combination of avoidance, design features, and 

the establishment of alternative access routes to 

these areas, the potential impacts can be adequately 

mitigated onsite. 

Yes

Relatively few transportation routes would be 

impacted by development in the SEZ. Alternative routes to the Arrow Canyon Range and Dry 

Lake can be established.

Wild Horses 

and Burros Yes No No

No mitigation is necessary as the SEZ is not part of a 

herd management area, and no horses or burros are 

known to exist in the area.

Yes

The SEZ is not part of a herd management area, 

and no horses or burros are known to exist in 

the area.

Wilderness 

and Lands 

with 

Wilderness 

Characteristics

Yes No No

No mitigation is necessary as there are no designated wilderness areas or lands with wilderness 

characteristics within or adjacent to the SEZ. Because of extensive existing development within the 

SEZ (roads, power lines, pipelines, active mill-site, 

electrical substation, and natural gas-fired power 

plant), the area lacks wilderness characteristics.

Yes Not applicable—resources would not be 

impacted.

1

 The Final Solar PEIS identified seven BLM-Nevada special status plants that occur in and around the Dry Lake SEZ. However, only the rosy two-toned penstemon is expected to occur in the Dry Lake SEZ. To 

determine potential impacts on BLM special status plants, the BLM reviewed occurrence data and “Clark County Rare Plant Habitat Modeling” (Hamilton and Kokos 2011). The habitat modeling report can be 

downloaded from the Clark County Desert Conservation Program website at http://bit.ly/Qbm19H. 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 51

Appendix B:

Regional and Dry Lake Solar Energy Zone Conceptual Models

Conceptual models are used to understand ecosystem interactions at an 

ecoregional scale (Tier 1), the solar development scale (Tier 2), and the 

SEZ-specific scale (Tier 3). The models used for the pilot Dry Lake Solar 

Energy Zone Solar Regional Mitigation Planning Project (as revised with 

stakeholder input) are presented here. Additional, more complex models 

may be constructed if needed to support impact assessment in the future. 

Tier 1 Conceptual Model, Mojave Basin and Range Ecoregion Model

Climatic and Physiographic System

Seasonal weather pattern, drought, wind, fire,

water runoff-infiltration, evaporation, soil erosion/

disturbance, soil development, soil chemistry,

freeze/thaw, nutrient cycling

Grazing, recreation, logging,

fire alteration, land conversion, contamination,

invasive species, air pollution, hunting,

wildlife/human conflict, trampling,

collecting

Snowpack formation/melt, water runoff-detention-recharge, surface 

flow, aquifer storage, surface-subsurface water exchange, evaporation, 

sediment erosion-deposition, 

connectivity, water chemistry, freeze/thaw

Human Systems

(Change Agents and

Drivers of Change):

Demography,

socioeconomics,

policy, resource

development

pressure

Water withdrawal/diversion, grazing,

invasive species, water pollution,

wetland drainage, fishing,

trampling, recreation

Montane Dry

Land System

Montane

Wet System

Basin Dry

Land System

Basin

Wet System

Natural Driver Human Driver
52 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Tier 2 Conceptual Model, Resource-Based Model

Landscape Elements

Latitude, elevation,

slope/topography/relief,

surficial geology, community

composition, spatial configuration,

landscape dynamics

Change Agent -

Disturbance

Human Activities

Natural (fire)

Greenhouse gas emissions,

climate change

 Fire, noise,

 pollution,

 soil disturbance,

 new structures/roads,

in-migration of workers

Fire, noise, invasive species,

 surface disturbance

Ecosystem

health**

Human element

related activities

Excavation

Soil disturbance, fire

Atmospheric

Conditions

Air Quality

Climate

Military Uses

Land and Realty

Transportation

Minerals

Development

Livestock and

Grazing

Wild Horses

and Burros

Lands with

Wilderness

Characteristics

Specially

Designated Areas

Environmental

Justice

Recreation

Human Elements* Ecosystem Components and Processes

BLM-Managed Activities and 

Resources

Paleontological

Acoustics

Visual

Resources

Cultural

Resources

Native

American

Concerns

Socioeconomics

Habitat availability,

composition structure

Pollination, 

herbivory,

seed dispersal

Habitat

availability

Nutrient availability,

sediment transport

Burrowing,

decomposition

Stabilization

Moisture,

nutrient

cycling

Sediment,

nutrient

transport

Habitat

and food 

availability

Plant production

Organic

matter

inputs

Wildlife

SPECIAL STATUS SPECIES

Animals

Vegetation

SPECIAL STATUS SPECIES

Vegetation

Soil Resources

Mineral nutrients, organic matter,

microorganisms, biological crust,

desert pavement

Hydrology

Recharge,

springs,

seeps

SURFACE

Lakes, riparian, floodplains, rivers,

and drainage networks

GROUNDWATER

* Human elements include the human concerns and related resources for which impact evaluation was included in the Final Solar PEIS. These are 

activities and resources with (or requiring) human engagement in one of the following ways: 

(1) requires active participation in management of a resource or activity (e.g., lands and realty, specially designated areas, transportation, 

grazing, mineral development, recreation, military uses; (2) addresses the perspective or perception of a resource (e.g., visual resources, 

acoustics, lands with wilderness characteristics, cultural); and/or (3) addresses human-specific values (e.g., cultural resources, Native American 

concerns, socioeconomics, environmental justice).

**Ecosystem health is referred to as the degree to which the integrity of the soil and the ecological processes of the ecosystem are sustained (BLM 

Handbook H-4180-1). Ecosystem health can influence Native American concerns, visual resources, specially designated areas, and recreation. 

Human elements can also influence ecosystem components (e.g., recreation can compact soils, hunting can impact species, etc.).

Legend

Resource and BLM-managed activities

Direction of processes

(orange arrows associated with anthropogenic disturbance)

Natural drivers

Change agents

Atmospheric conditions
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 53

Tier 3 Conceptual Model, Dry Lake SEZ Solar Development Model

Landscape Elements

Latitude, elevation,

slope/topography/relief, 

surficial geology, community

composition, spatial configuration,

landscape dynamics

Greenhouse gas emissions,

climate change

 Fire, noise,

 pollution, new

 structures/roads,

rights-of-way, in-migration of

 workers, loss of

 ecosystem,

 surface

 disturbance,

 vegetation

 clearing, lighting

Fire, noise, surface disturbance,

 loss of habitat, water

 withdrawal, introduction

 of invasive species

Ecosystem

health**

Human element

related activities

Soil disturbance, fire

Atmospheric

Conditions

Air Quality

Climate

Specially

Designated Area

Coyote Springs Area

of Critical

Environmental

Concern

Specially

Designated Areas

Desert National Wildlife

Refuge; Old Spanish National 

Historic Trail; Arrow Canyon 

Wilderness Area; Muddy

Mountains Wilderness Area,

and Nellis Dunes Special

Recreation Management

Area

Recreation

Off-road vehicle, hunting

Mineral Development

Gypsum

Military Uses

Nellis Air Force

Base

Tortoise habitat,

potential

translocation

site

Human Elements* Ecosystem Components and Processes

BLM-Managed Activities and 

Resources

Cultural

Resources

Native

American

Concerns

Habitat availability,

composition structure

Pollination, 

herbivory,

seed dispersal

Habitat

availability

Nutrient availability,

sediment transport

Burrowing, decomposition

Stabilization

Moisture,

nutrient

cycling

Sediment,

nutrient

transport

Habitat and food 

availability

Plant

production

Organic

matter

inputs

Wildlife

Mule deer, kit fox

SPECIAL STATUS SPECIES

Desert tortoise, golden eagle, Gila monster,

Mojave Desert sidewinder, ferruginous hawk,

loggerhead shrike, and

Le Conte’s thrasher

Migratory birds

Soil Resources

Desert pavement, biological crust,

mineral nutrients, organic matter,

microorganisms

Hydrology***

Recharge,

springs,

seeps

* Human elements include the human concerns and related resources for which impact evaluation was included in the Final Solar PEIS. These are 

activities and resources with (or requiring) human engagement in one of the following ways: 

(1) requires active participation in management of a resource or activity (e.g., lands and realty, specially designated areas, transportation, 

grazing, mineral development, recreation, military uses; (2) addresses the perspective orperception f a resource (e.g., visual resources, 

acoustics, lands with wilderness characteristics, cultural); and/or (3) addresses human-specific values (e.g., cultural resources, Native American 

concerns, socioeconomics, environmental justice).

** Ecosystem health is referred to as the degree to which the integrity of the soil and the ecological processes of the ecosystem are sustained (BLM 

Handbook H-4180-1). Ecosystem health can influence Native American concerns, visual resources, specially designated areas, and recreation. 

Human elements can also influence ecosystem components (e.g., recreation can compact soils, hunting can impact species, etc.).

*** Unavoidable hydrologic impacts may occur due to changes in drainage and recharge patterns. Potential impacts to water 

availability will be mitigated onsite through the implementation of a net neutral use policy (water rights must be purchased).

Legend

Impacts to resources can be mitigated onsite

Impacts to resource may be unavoidable

Impacts to resource considered unavoidable

Direction of processes

(orange arrows associated with solar development disturbance)

Natural drivers

Change agent

Atmospheric conditions

SURFACE

Riparian, ephemeral washes, wetlands,

drainage networks

GROUNDWATER

Garnet Valley, Hidden Valley,

Coyote Springs

Vegetation

Creosotebush, white bursage,

yucca, cactus

SPECIAL STATUS SPECIES

Rosy two-toned penstemon

Visual

Resources

Loss of access

Land use conflict

Solar

Development

Disturbance
54 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Appendix C:

Summary Table: Impacts that May Warrant Regional

Mitigation for the Dry Lake Solar Energy Zone1

Resource/ 

Issue

Unavoidable 

Impacts? 2

How certain 

is it that the 

unavoidable 

impacts will 

occur?

How significant are 

the unavoidable 

impacts onsite?

How significant are the unavoidable 

impacts of developing the Dry Lake 

SEZ in the region (Mojave Desert)? 3

Role in the 

ecosystem? 4

Other

considerations

Are potential 

unavoidable 

impacts likely to 

warrant regional 

mitigation?

Soils/

Erosion Yes Certain

Very—expect the total 

loss of biological soils 

and/or desert pavement 

over the entire 

developable area.

Trend: Decreasing. Approximately 8.8% of 

soil resources in the Mojave Desert have 

been altered by human development. For 

example, 3.8% of desert pavement in the 

Mojave Desert has been altered. A 0.2% 

increase in alteration of desert pavement 

is expected by 2025.

Basic

component.

Natural 

regeneration of 

biological soils 

and/or desert 

pavement is 

very slow in the 

Mojave Desert.

Yes

Wildlife Yes Certain

Very—expect the loss 

of habitat for most

general wildlife species 

over the entire 

developable area.

Trend: Decreasing. Approximately 7.1% of 

wildlife habitat in the Mojave Desert has 

been altered. A 1% increase in alteration is 

expected by 2025.

Basic

component.

Yes—indirectly (as 

a component of the 

ecosystem).

Special 

Status 

Species - 

Animals

Yes

Loss of habitat is 

certain. Loss of 

animals is likely.

Very—expect the 

total loss of habitat for 

special status animal 

species over the entire 

developable area.

Trend: Decreasing. Habitat for special 

status species has been decreasing in the 

Mojave Desert; for example, 11.1% of 

habitat for desert tortoise has been altered 

at present, and an additional 1.4% is 

expected to be altered by 2025.

Basic

component 

(along with 

other wildlife).

Mitigation of 

listed species is 

required by law 

and/or policy.

Yes

Vegetation Yes Certain

Very—expect the loss 

of all vegetation over the 

developable area of the 

SEZ, though mitigation 

may result in some 

remaining or replanted 

vegetation.

Trend: Decreasing. Approximately 7.1% 

of natural vegetation communities in 

the Mojave Desert have been altered by 

human development. A 1% increase in 

alteration is expected by 2025.

Basic

component.

Natural regeneration of native 

vegetation is 

slow in the 

Mojave Desert.

Yes

Special 

Status 

Species - 

Vegetation

Yes

Loss of habitat is 

certain. Loss of 

plants is likely.

Very—expect the total 

loss of special status 

species plants and/or 

habitat in the

developable area.

Trend: Decreasing. Special status species 

plant habitat in the Mojave Desert is 

expected to continue to decline due to 

human development. 

Basic

component 

(along with 

other

vegetation).

Mitigation of 

special status 

species plants 

is required BLM 

policy.

Yes

Visual 

Resources Yes Certain

Somewhat. Visual 

quality of the SEZ and 

surrounding area is 

already altered.

Somewhat. Approximately 53% of 

viewsheds in the Mojave Desert have been 

altered. 

Land use 

(human 

element).

Other resource 

mitigation that 

involves restoring the physical 

and biological 

integrity to the 

landscape may 

also mitigate 

visual resources 

as long as the 

visual design 

elements of 

form, line, color, 

and texture are 

factored into 

the restoration 

planning and 

design.

Visual resources must 

be included as a part 

of the site selection 

criteria for mitigating 

other biological resources that warrant 

habitat enhancement 

treatments, as a 

co-beneficiary of 

the mitigation 

effort. Restoration or 

protection of intact 

ecosystems can also 

restore or protect 

visual resources.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 55

Resource/ 

Issue

Unavoidable 

Impacts? 2

How certain 

is it that the 

unavoidable 

impacts will 

occur?

How significant are 

the unavoidable 

impacts onsite?

How significant are the unavoidable 

impacts of developing the Dry Lake 

SEZ in the region (Mojave Desert)? 3

Role in the 

ecosystem? 4

Other

considerations

Are potential 

unavoidable 

impacts likely to 

warrant regional 

mitigation?

Specially 

Designated 

Areas

Maybe—for 

impacts to 

desert tortoise 

at the Coyote 

Springs ACEC.

Maybe—for 

visual impacts 

to the Desert 

National Wildlife Refuge and 

other specially 

designated 

areas.

Possible—if

tortoise migrate 

or are translocated to the Coyote 

Springs ACEC.

Visual impacts—

unknown. 

Lack specific 

assessments.

Unknown—Impacts of 

increasing the tortoise 

population in the ACEC 

have not been assessed.

Visual impacts—unknown. Lack specific 

assessments.

Unknown. However, any impact that 

adversely affects an ACEC in its ability to 

support desert tortoise recovery ultimately 

affects the overall recovery effort.

Visual impacts—unknown. Lack an 

assessment of the conditions and trends 

of visual resources as seen from other 

specially designated areas.

Coyote Springs 

ACEC: the 

desert tortoise 

is a basic 

component. 

Visual impacts 

to specially 

designated 

areas: land 

use (human 

element).

Possible to minimize adverse 

impacts onsite 

(in the ACEC) 

by extending 

desert tortoise 

fencing. 

Possible to minimize adverse 

visual impacts 

through onsite 

mitigation that 

reduces the 

degree of visual 

contrast from 

new development.

Not at this time, but 

may be required if 

additional analysis 

reveals an adverse 

impact.

Unknown at this time 

for visual impacts. 

Onsite mitigation 

measures may be 

adequate for protecting the viewsheds of 

specially designated 

areas.

Military Yes

Unlikely. Aircraft 

emergencies 

occuring over the 

SEZ that pose a 

threat to human 

life and/or

property are rare.

Somewhat. There is an 

elevated risk of bodily 

harm to aircrew who 

eject and land in the 

area and in a solar 

facility. The potential 

for property damage to 

the facility could alter 

insurance rates.

Somewhat. Coordination with the military 

and possible height restrictions will 

address most impacts.

Land use 

(human 

element).

Difficult impact 

to mitigate. No

Native 

American 

Concerns

Hydrology. Yes, 

if nonphotovoltaic 

technology is 

permitted. 

Habitat loss—

yes

Cultural—

maybe

Unlikely for 

hydrology. 

Certain for

habitat loss.

Unknown for 

cultural resources 

until Class III cultural inventories 

are completed.

See Wildlife and Special 

Status Species entries in 

this table.

See Wildlife and Special Status Species 

entries in this table.

Human 

element.

Unknown at this 

time. Consultation on project 

applications will 

determine whether 

mitigation for Native 

American concerns is 

warranted.

Invasive/ 

Noxious 

Weeds

Maybe—if 

weed management plan 

fails.

Not likely. Onsite 

mitigation measures are expected 

to protect against 

the establishment 

and/or spread of 

invasive/noxious 

weeds.

Not particularly 

significant. Onsite 

mitigation measures are 

expected to minimize 

any impacts. Monitoring 

will facilitate timely 

discovery of infestations. 

Invasive/noxious weed infestation is a 

problematic trend in the region. However, 

onsite mitigation is expected to minimize 

any impacts on the site, as well as to the 

region.

Change agent.

No, but restoration or 

protection of intact 

ecosystems will also 

restore or protect 

the ability to resist 

invasive species.

1

 A version of this table was presented for stakeholder review through the Dry Lake Solar Energy Zone project website in December 2012; this revised version was posted to the website in February 2013.

2

 Unavoidable impacts are those that cannot be mitigated onsite by avoidance and/or minimization. Avoidance is accomplished by imposing spatial and/or temporal restrictions. Minimization is accomplished 

using design features and/or best management practices.

3

 Data to determine trends were taken from the BLM Mojave Basin and Range Rapid Ecoregional Assessment.

4

 Reference the conceptual models in Appendix B.
56 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Resource/ 

Issue

Unavoidable 

Impacts? 2

How certain 

is it that the 

unavoidable 

impacts will 

occur?

How significant are 

the unavoidable 

impacts onsite?

How significant are the unavoidable 

impacts of developing the Dry Lake 

SEZ in the region (Mojave Desert)? 3

Role in the 

ecosystem? 4

Other

considerations

Are potential 

unavoidable 

impacts likely to 

warrant regional 

mitigation?

Hydrology 

(Water/ 

Watershed/ 

Water 

Quality)

Groundwater—maybe

Surface 

Hydrology—

maybe. Reconfiguration 

of topography 

can alter surface hydrology.

Groundwater—

unlikely. The 

BLM will review 

all applications 

to validate net 

neutral water use 

(i.e., groundwater purchased 

from holders of 

currently used 

existing senior 

water rights).

Surface

hydrology—

likely.

Surface hydrology: Not 

especially significant. 

Area of very low rainfall 

( approximately 4 

inches/year). Closed 

hydrologic basin.

Not particularly significant, but there is a 

regional decline in unaltered ephemeral 

stream channels.

Basic

component.

Groundwater—no.

Surface Hydrology—

yes (indirectly as a 

component of the 

ecosystem).

Riparian

Surface 

Hydrology—

Maybe. Reconfiguration 

of topography 

can alter surface hydrology.

Somewhat—

while major 

riparian areas 

within the SEZ 

are designated 

nondevelopment 

areas, run-off 

patterns and 

sediment load 

will be altered by 

reconfiguration of 

the topography 

on the rest of the 

SEZ. Onsite mitigation measures 

are expected to 

minimize impacts.

Not especially significant; PEIS analyses show 

about five intermittent 

ephemeral stream 

reaches with moderate 

sensitivity to disturbance within the SEZ. 

Not particularly significant. The occurrence 

of intact riparian systems is declining in 

the Mojave Basin and Range ecoregion. 

Basic

component.

No, not directly. 

While there may be 

impacts to riparian 

systems, preservation 

and/or restoration 

of intact ecosystems 

in the region that 

include riparian areas 

will slow the regional 

decline in intact 

riparian ecosystems.

Cultural Maybe. 

Low—previous 

Class III cultural 

inventories in the 

SEZ and vicinity 

indicated risk 

of resource loss 

is low.

Depends on results of 

Class III inventory of 

SEZ and if significant 

(eligible) sites are 

discovered.

Human 

element.

Onsite 

mitigation 

measures were 

determined to 

be adequate 

for addressing 

known cultural 

resources.

Not at this time. 

However, if significant resource values 

are discovered during 

the predevelopment 

survey, implementing the required 

protection measures 

as established in 

the memorandum 

of agreement may 

result in regional 

mitigation measures.

Resources/issues with no 

unavoidable impacts:

Acoustics

Air Quality

Environmental Justice

Fire

Hazardous Waste

Lands and Realty

Livestock Grazing

Minerals

Paleontological

Recreation (includes Travel 

 Management Areas)

Socioeconomics

Transportation

Wild Horses and Burros

Wilderness and Lands with

 Wilderness Characteristics
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 57

Appendix D:

BLM Screening of Candidate Regional Mitigation Sites

for the Dry Lake Solar Energy Zone

The BLM interdisciplinary team used this screening tool for evaluating 

and recommending candidate sites to the BLM authorized officer (see 

definitions for criteria categories at the end of this appendix).

# Criteria SEZ Candidate Sites Notes

 Dry Lake Solar 

Energy Zone

Gold Butte 

ACEC, Las 

Vegas Field 

Office

Mormon Mesa 

ACEC, Ely District 

and Las Vegas 

Field Office

Coyote 

Springs ACEC, 

Las Vegas 

Field Office

Piute-El 

Dorado ACEC, 

Las Vegas 

Field Office

Coyote 

Springs 

Enhanced

Site Characteristics

1 Contiguous area of 

site (acres) 3,471

Part A: 

186,909

Part B: 

119,097

Part C: 38,431

149,000 75,500 328,242

149,278 acres

(mix of BLM, 

BLM-ACEC, 

and FWS 

Desert 

National 

Wildlife 

Refuge)

The size, in acres, of the candidate 

site.

2 For ACECs, reason for 

designation n/a see note 1 see note 6

If the candidate site encompasses 

land in an ACEC, this field 

represents the value(s) present 

that the ACEC was established to 

protect.

3 Visual Resource 

Management Class Class III

Class I, II 

(70%), and III 

areas present

Class III Class III Class III Class III

If the VRM class of a candidate site 

is of higher value than that of the 

SEZ, improvements provided by 

regional mitigation would result in 

improvements to the higher VRM 

class - no points are assigned to 

this characteristic.

4

Consistent 

with resource 

management plan?

n/a √ √ √ √

5 Same HUC 4 

watershed?

Lower ColoradoLake Mead (1501) √ √ √

X

Central Nevada 

Desert Basins 

(1606)

√

The HUC 4 watershed is used to 

evaluate the sites; sites not in the 

same HUC 4 watershed would 

have a fairly strong hydrologic 

disconnect from Dry Lake SEZ.

6

Mitigation tool 

(restoration/

enhancement, 

acquisition, banking, 

withdrawal, special 

designation, etc.)

n/a Restoration/ 

enhancement

Restoration/ 

enhancement

Restoration/ 

enhancement

Restoration/ 

enhancement

Restoration/ 

enhancement, 

restriction of 

activities

The type(s) of mitigation tool that 

would be implemented at the site. 
58 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

# Criteria SEZ Candidate Sites Notes

 Dry Lake Solar 

Energy Zone

Gold Butte 

ACEC, Las 

Vegas Field 

Office

Mormon Mesa 

ACEC, Ely District 

and Las Vegas 

Field Office

Coyote 

Springs ACEC, 

Las Vegas 

Field Office

Piute-El 

Dorado ACEC, 

Las Vegas 

Field Office

Coyote 

Springs 

Enhanced

Mitigation Site Qualifying Criteria

7 In SEZ ecoregion? Mojave Basin and 

Range √ √ √ √See note 2 √

8 In SEZ ecological 

subregion? Eastern Mojave √ √ √ √ √

9

Meets priorities for 

Endangered Species 

Act critical habitat?

n/a √ √ √ √ √

10

Mitigates 

unavoidable 

impacts to “least 

common and most 

geographically 

restricted species?”

Desert tortoise and 

rosy two-toned 

penstemon

√ √ √ √ √

Desert tortoise habitat is 

present in all the candidate 

sites, but not necessarily rosy 

two-toned penstemon, which 

will be mitigated for using 

other measures (i.e., onsite seed 

collection prior to development 

and sponsorship into the Center 

for Plant Conservation National 

Collection of Rare Plants). 

11

Mitigates for all 

or most identified 

unavoidable impacts 

that warrant regional 

mitigation?

Unavoidable 

impacts that 

warrant mitigation 

at the Dry Lake 

SEZ include soils, 

vegetation, 

wildlife, specialstatus species, and 

visual resources. 

Impacts to Native 

American concerns 

that warrant 

mitigation may be 

identified through 

consultation. 

√ √ √ √ √

12

Similar landscape 

value, ecological 

functionality, 

biological value, 

species, habitat 

types, and/or natural 

features?

Creosote-white 

bursage desert 

scrub vegetation 

community is 

critical resource for 

mitigation.

√ √ √ √ √ Site includes resources critical to 

meet mitigation objectives.

13 Provides adequate 

geographic extent? n/a √ √ √ √ √

Provides area for mitigation 

at least as large as the entire 

developable area of the SEZ.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 59

# Criteria SEZ Candidate Sites Notes

 Dry Lake Solar 

Energy Zone

Gold Butte 

ACEC, Las 

Vegas Field 

Office

Mormon Mesa 

ACEC, Ely District 

and Las Vegas 

Field Office

Coyote 

Springs ACEC, 

Las Vegas 

Field Office

Piute-El 

Dorado ACEC, 

Las Vegas 

Field Office

Coyote 

Springs 

Enhanced

Stop Here For Any of the Candidate Sites That Did Not Meet One or More of the Above Qualifying Criteria

14

Presence of unique/

valuable resources or 

features

√ √ √ √ √

14a Perennial, protected 

sources of water? No √

14b Unique species 

assemblages? None known

14c

Protected species 

and/or critical 

habitat?

Desert tortoise √ √ √ √

Contiguous 

“highest 

value” tortoise 

habitat

14d Desert washes or 

ephemeral playas? Avoided √ Pahranagat Wash

14e Other?

Vegetation types: 

creosotebush, 

white bursage, 

yucca, cactus. Rare 

plants: rosy twotoned penstemon 

(Penstemon 

bicolor spp. 

roseus). Wildlife: 

mule deer, kit 

fox. Specialstatus species: 

desert tortoise, 

golden eagle, Gila 

monster, Mojave 

Desert sidewinder, 

ferruginous hawk, 

loggerhead shrike, 

Le Conte’s thrasher; 

migratory birds. 

Also present: desert 

pavement, biologial 

crusts

Bighorn sheep 

habitat

Bighorn sheep 

habitat

Corridor for 

bighorn sheep

15 Sources of data for 

the site

Final Solar 

PEIS, BLM 

interdisciplinary 

team, stakeholders

Southern 

Nevada District 

Office

Southern

Nevada District 

Office

Southern 

Nevada District 

Office

Southern 

Nevada District 

Office

The Nature 

Conservancy
60 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

# Criteria SEZ Candidate Sites Notes

 Dry Lake Solar 

Energy Zone

Gold Butte 

ACEC, Las 

Vegas Field 

Office

Mormon Mesa 

ACEC, Ely District 

and Las Vegas 

Field Office

Coyote 

Springs ACEC, 

Las Vegas 

Field Office

Piute-El 

Dorado ACEC, 

Las Vegas 

Field Office

Coyote 

Springs 

Enhanced

Effectiveness / Additionality

16

To what extent can 

the full spectrum of 

regional mitigation 

goals/objectives be 

met simultaneously? 

Use scale of 1 (low) 

to 5 (high).

Goals: Mitigate for 

impacts to desert 

tortoise, special 

status species 

animals and plants, 

visual resources, 

and ecosystem loss.

4 4 4 4 4

17

How effective will 

the mitigation be 

in the context of 

achieving mitigation 

goals/objectives 

for conserving/

restoring ecosystem 

intactness? Use scale 

of 1 (low) to 5 (high).

n/a 5 5 5 5 5

18

For mitigation on 

BLM-administered 

lands, mitigation 

consists of actions 

not eligible for BLM 

or other sources of 

funding.

n/a √ √ √ √ √

Feasibility

19

Based on action 

required (e.g., 

restoration, BLM land 

management action, 

land acquisition, 

congressional 

action), how difficult 

will implementation 

be? Use scale of 

1 (difficult) to 5 

(relatively easy). See 

note 5.

n/a 5

(restoration)

5

(restoration)

5

(restoration)

5

(restoration)

5 

(restoration, 

enhancement)

20

Timeframe needed 

to establish site as 

mitigation location 

(estimated years).

n/a 0-1 0-1 0-1 0-1 0-1

21

Timeframe for 

achieving mitigation 

goals and objectives 

from implementation 

(estimated years).

n/a 0-30 0-30 0-30 0-30 ? Timeframe not assesssed by The 

Nature Conservancy.

22 Cost estimate n/a Total $42,672,000 over 30 yrs ($1,422,400/yr) pooled across all 4 ACECs $1,728/acre 

($150 million)
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 61

# Criteria SEZ Candidate Sites Notes

 Dry Lake Solar 

Energy Zone

Gold Butte 

ACEC, Las 

Vegas Field 

Office

Mormon Mesa 

ACEC, Ely District 

and Las Vegas 

Field Office

Coyote 

Springs ACEC, 

Las Vegas 

Field Office

Piute-El 

Dorado ACEC, 

Las Vegas 

Field Office

Coyote 

Springs 

Enhanced

Durability

23

How durable would 

the mitigation be 

from a timeframe 

and management 

perspective? Use 

scale of 1 (low) to 5 

(high).

n/a 5 4 4 4 4

Rated the ACECs as having a 

relatively high durability (4) by 

virtue of being designated in the 

RMP for special management and 

because Southern Nevada District 

Office recommends increased law 

enforcement; Gold Butte rated 

higher because it is a site most 

likely to be resistant to the effects 

of climate change.

24

How durable would 

the mitigation 

be in the context 

of permanence 

of conservation 

and biodiversity 

protections? Use 

scale of 1 (low) to 5 

(high).

n/a 5 4 4 4 4

Risk

25

What are the 

constraints or threats 

to success?

n/a see note 3 see note 4

26

To what extent 

will surrounding 

land uses impact 

mitigation success? 

Use scale of 1 

(considerable) to 5 

(low).

n/a 5 5 5 5 3

27

What is the relative 

probablility of 

success? Use scale of 

1 (low) to 5 (high).

n/a 5 5 5 5 5

Preliminary Ranking (see note 7) 45 43 43 40 40

Notes:

(1) Gold Butte ACEC: Part A: desert tortoise; Part B: sensitive plants, desert bighorn sheep, desert tortoise; Part C: high-elevation relict forest stands and desert bighorn sheep habitat. 

Mormon Mesa ACEC: desert tortoise habitat.

Coyote Springs ACEC: functional corridors of habitat between desert tortoise recovery units.

Piute-El Dorado ACEC: desert tortoise habitat.

(2) A portion of Piute-El Dorado ACEC appears to be located in the Central Basin and Range ecoregion.

(3) Constraints include funding availability and appropriate conditions for seed germination and establishment; for Coyote Springs ACEC, a relatively short segment of the Clark, Lincoln, 

and White Pine Counties Groundwater Development Project pipeline and power line right-of-way (approximately 6.5 mi and 0.15 mi, respectively); and the associated water treatment 

facility and buried storage reservoir (approximately 75 acres total) are located within the ACEC but outside of the designated Lincoln County Conservation, Recreation, and Development 

Act utility corridor that runs along U.S. Route 93.

(4) Adjacent lands at risk from future development around Coyote Springs golf course which could impact groundwater and reduce conservation value; a majority of the Clark, Lincoln, and 

White Pine Counties Groundwater Development Project pipeline and power line right-of-way in this area are located within the designated Lincoln County Conservation, Recreation, and 

Development Act utility corridor that runs along U.S. Route 93, and none of the right-of-way is located within the USFWS Desert National Wildlife Refuge.

(5) For scale, consider the following: restoration, relatively easy (5); BLM land management action, not easy to moderately complicated (3-5); land acquisition, moderately complicated to 

not very easy (1-3); congressional action, not very easy (1).

(6) Includes part of the Coyote Springs ACEC which was established to preserve functional corridors of habitat between desert tortoise recovery units.

(7) Scores are calculated based on entries in blue-shaded cells as follows: all scaled values (i.e., ratings from 1 to 5) are summed; 1 point is added for each check mark; 2 point are deleted 

for each X.
62 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Definitions for Criteria Categories

Site characterization criteria: characteristics of the site that are largely known or measureable, that determine whether the site is comparable to the SEZ site and/or is suitable for 

supporting effective mitigation actions.

Effectiveness/additionality criteria: factors that (1) measure how effective the actions at the mitigation site will be in terms of meeting the BLM’s mitigation goals/objectives for the SEZ 

and (2) assess whether or not the action meets the requirement for additionality (i.e., is the site eligible for BLM or other sources of funding).

Feasibility criteria: factors that measure the degree of difficulty in terms of implementing the actions at the mitigation site, the amount of time required to successfully implement the 

mitigation action(s), and the total and per-acre cost of the mitigation.

Durability criteria: factors that measure the durability of the mitigation in terms of the permanence and stability of the mitigation area.

Risk criteria: factors that measure the degree to which external factors might jeopardize long-term success of the mitigation action(s).
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 63

Appendix E:

Mitigation of Visual Resource Impacts

in the Dry Lake Solar Energy Zone

1.0 Introduction 

Utility-scale solar development 

often involves a long-term 

commitment of relatively large 

areas of land and may result in 

substantial impacts to visual 

resource values. Unavoidable 

impacts to visual resources are 

those that cannot be adequately 

mitigated onsite by avoidance 

and/or by the implementation 

of design features meant to 

minimize impacts that lead to a 

loss or reduction in inventoried 

visual values. It is recognized that 

regional mitigation may not always 

be warranted for all unavoidable 

visual resource impacts. The BLM’s 

interim policy, Draft Manual Section 

1794, “Regional Mitigation” (referred 

to as the Regional Mitigation 

Manual throughout the rest of 

this appendix) outlines interim 

policy for taking a landscape-scale 

regional approach to mitigating 

project impacts to resources and 

values managed by the BLM. This 

interim policy guided the process 

developed for determining the 

need to mitigate visual impacts 

in the Dry Lake Solar Energy Zone 

(SEZ) at a regional level.

The process of preliminarily 

identifying unavoidable impacts to 

all resources (e.g., soils, ecological 

resources, cultural resources) that 

may warrant regional mitigation 

(explained in Sections 2.4.3.1 and 

2.4.3.2 of this strategy) evaluates: 

1. Resource condition and 

regional trends affecting the 

resource.

2. Importance placed on the 

resource in the land use plan.

3. Rarity, legal status, or state/

national policy of the resource. 

4. Resilience of the resource in the 

face of change and impact.

This appendix provides 

additional information on a strategy 

for considering regional mitigation 

to compensate for certain 

unavoidable impacts to visual 

values that may result from solar 

development within the Dry Lake 

SEZ. The criteria for preliminarily 

identifying unavoidable impacts 

to visual resource values that 

may warrant regional mitigation 

follows the same logic used for all 

resources outlined in the Dry Lake 

Solar Regional Mitigation Strategy 

(SRMS), but the evaluation is 

tailored to consider the following:

1. General regional condition of 

the visual resource reflected in 

the visual resource inventory 

(VRI).

2. Scarcity of the resource at the 

regional scale.

3. Resilience of the resource in the 

face of change and impact.

4. Importance placed on the 

resource in the land use plan.

In addition to the Regional 

Mitigation Manual, the process 

described in this appendix 

follows the guidance outlined 

in the BLM technical reference 

titled “Procedural Guidance 

for Developing Solar Regional 

Mitigation Strategies” (SRMS Tech 

Reference), Appendix F: Mitigation 

of Impacts on Visual Resources. 

Additional sources used to develop 

the following include the BLM’s 

“Visual Resource Management” 

Manual MS-8400, “Visual Resource 

Inventory” Handbook H-8410-1, and 

“Visual Resource Contrast Rating” 

Handbook H-8431-1. 

2.0 Visual Resources within the Dry 

Lake Solar Energy Zone and the 

Mojave Desert Ecoregion

This appendix addresses two 

aspects of visual resources, which 

are mentioned in this strategy 

under 2.5.1, Background on 

Regional Goals: 

1. Change to visual resource 

values within the boundary of 

the SEZ. 

2. Change within the SEZ that 

would affect the visitor’s 

scenery viewing experience 

from lands with legislated 

protection for scenery and/or 

landscape settings, including 

the following types of specially 

designated areas:

a. National parks. 

b. National wildlife refuges.

c. Wilderness areas.

d. National scenic and historic 

trails. 

e. Special recreation 

management areas.

This appendix follows the 

progression of basic steps to 

ascertain whether regional 
64 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

mitigation is warranted as outlined 

in the SRMS Technical Reference, 

Section 2.4, Solar Regional 

Mitigation Strategy Elements (BLM 

forthcoming).

2.1 Define the Baseline for 

Assessing Unavoidable Impacts 

The baseline for assessing 

unavoidable impacts is drawn 

from the impact analysis and 

VRIs performed for the “Final 

Programmatic Environmental 

Impact Statement (PEIS) for 

Solar Energy Development in Six 

Southwestern States” (Final Solar 

PEIS) (BLM and DOE 2012). The VRIs 

describe and quantify visual values 

in terms of scenic quality, public 

sensitivity, and distance zones (see 

BLM Handbook H-8410-1). Data, 

figures, trends, and statements of 

value used here were derived and 

extrapolated from the following 

VRIs for lands within the Mojave 

Desert ecoregion:

•	 Southern Nevada District.

•	 Ely District (Nevada).

•	 Palm Springs-South Coast Field

Office (California).

•	 Barstow Field Office (California).

•	 Needles Field Office (California).

•	 Ridgecrest Field Office

(California). 

These VRIs include 90% of the 

BLM-administered lands within 

the Mojave Desert ecoregion. 

VRI data were not available for 

the remaining 10% of the BLMadministered lands within the 

Mojave Desert ecoregion. The areas 

not inventoried are located along 

the outer edges of the ecoregion 

in the following BLM areas of 

responsibility:

•	 Kingman Field Office (Arizona).

•	 Arizona Strip Field Office.

•	 Grand Canyon-Parashant

National Monument (Arizona).

•	 St. George Field Office (Utah).

2.2 Regional Condition and Trends 

of the Visual Resource Values

The regional condition of the 

visual resource is extrapolated 

from the “scenic quality” rating 

evaluation for the “cultural 

modification” factor (see Figure 1). 

Cultural modification is defined as 

“any man-caused change in the 

land form, water form, vegetation, 

or the addition of a structure which 

creates a visual contrast in the basic 

elements (form, line, color, texture) 

of the naturalistic character of a 

landscape” (BLM Manual 8400). 

BLM Handbook H-8410-1 explains 

that cultural modifications may 

distract or complement the natural 

landscape setting and result in 

either a reduction in value, increase 

in value, or no change in value. 

A review of the condition within 

the Mojave Desert ecoregion, based 

on the VRIs, indicated that 47% of 

the BLM-administered lands remain 

visually intact with no cultural 

modifications, or with cultural 

modifications present, but not 

contributing to or subtracting from 

the other scenic quality attributes. 

Fifty-three percent of the 

ecoregion landscape contains 

cultural modifications that are 

either discordant or complementary 

to the landscape’s scenic quality 

(48% of the landscape received a 

negative score ranging from -1 to 

-4, reducing the landscape’s scenic 

quality, while 5% received a positive 

score).

Figure 1. Composite map compiled from the visual resource inventories for cultural modifications 

within the Mojave Desert ecoregion. 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 65

The Dry Lake SEZ is located 

within Scenic Quality Rating 

Unit 037-Dry Lake Valley and is 

documented as having cultural 

modifications that have discordant 

characteristics resulting in a 

negative score of -1.5. The cultural 

modification score was subtracted 

from the baseline score of 7, which 

is the sum of the other six scenic 

quality evaluation key factors (see 

SRMS Tech Reference, Appendix F) 

leading to a final outcome of 5.5, 

which assigns a rating of Scenic 

Quality C.

Locating the Dry Lake SEZ 

within the culturally modified SQRU 

037 (see Figure 2) will result in 

clustering new development with 

existing development, which will 

help curtail the perpetuating trend 

of new development sprawling 

into landscapes with naturalistic 

character. Onsite mitigation at the 

Dry Lake SEZ should be planned 

and implemented to avoid further 

reduction in the scenic quality.

plans and revisions of land use 

plans “consider the relative scarcity 

of the values involved and the 

availability of alternative means 

(including recycling) and sites for 

realization of those values.” The VRIs 

provide an assessment of three 

visual values (i.e., scenic quality, 

public sensitivity, and distance 

zones) and quantity of those values 

to determine the relative scarcity of 

a particular visual resource within 

the region.

All three visual values can 

be assessed for scarcity, but the 

principal value serving as the driver 

to protect scarce visual resources 

lies within the scenic quality 

value, while public sensitivity 

and distance zones serve as 

qualifiers. The inventoried visual 

values are measured in acres, 

providing information necessary for 

quantifying scarcity and abundance 

at the local and regional scale. 

While FLPMA does not define a 

quantified threshold for visual 

resource scarcity, or for any other 

resource, the assessment of scarcity 

is a basic statistical evaluation of 

the distribution of values across 

the landscape. The values are first 

evaluated independently and then 

in combination in the context of the 

VRI Class Matrix (Figure 3). 

Figure 2. Scenic Quality Rating Unit 037 where 

the Dry Lake Solar Energy Zone is located and 

which has a cultural modification score of -1.5 

(Southern Las Vegas Visual Resource Inventory).

Avoiding further reduction in 

the cultural modification factor 

could be achieved through wellplanned implementation of the 

visual design features outlined in 

the Final Solar PEIS. Although solar 

development in the SEZ will result 

in increased cultural modification, 

thoughtful planning of the 

development patterns, architectural 

treatments, and repetition of the 

low visual contrasting qualities 

of existing and future common 

elements (e.g., use of Cor-Ten 

weathering steel transmission 

towers), may result in visually 

unifying the SEZ development with 

the existing scattered facilities that 

appear to be randomly located 

within the landscape. Visually 

integrating new and existing 

facilities may help create the visual 

impression of a well-planned 

industrial solar energy development 

that better harmonizes with the 

landscape setting. If well-executed, 

the planned development could 

conceivably maintain the current 

cultural modification score for the 

SEZ lands.

2.3 Scarcity 

The Federal Land Policy and 

Management Act (FLPMA) Section 

202(c)(6) requires that land use 

Figure 3. Visual Resource Inventory Class Assignment Matrix.

* If adjacent area is Class III or lower 

(i.e., Class II), assign Class III. 

If higher (i.e., Class IV), assign Class IV.

Basis for

Determining

Visual

Resource

Inventory

Classes

Visual Sensitivity Levels

High Medium Low

I I I I I I I

II II II II II II II

II III III IV IV IV

III IV IV IV IV IV IV

f/m b s/s f/m b s/s s/s

Distance Zones

Special Areas

Scenic

Quality

A

B

C

III

 IV*
66 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

While scarcity of resources 

may imply worthiness for 

protection, in visual resources, 

scarcity may serve as either a 

value worthy of preserving or, in 

some circumstances, exhibit rare 

opportunities for development. 

Therefore, it is critical to review 

the scarcity of each visual value 

independently and then in 

combination to best understand 

the opportunities and constraints 

on development or regional 

mitigation.

2.3.1 Scenic Quality Scarcity

Scenic quality scarcity 

should be evaluated from two 

perspectives. First, note the 

scoring on the “Scenic Quality Field 

Inventory” BLM Form 8400-1, in 

which scarcity of scenic landscape 

features is documented. The second 

involves evaluating the level of 

scarcity within the full range of 

scenic quality values inventoried for 

the region.

2.3.1.1 Scarcity Value within the 

Scenic Quality Evaluation of the 

Visual Resource Inventory

When inventorying visual 

resources, scarcity is one of the 

seven key evaluation factors 

considered in the scenic quality 

evaluation (see Figure 4). The 

“scarcity factor” ranges in score 

from “1” for common landscapes 

to “5” or more for landscapes 

identified as “one of a kind,” 

“unusually memorable,” or “very 

rare”. A score of 5 and above, and 

in some circumstances 4, should 

be considered scarce and should 

justify onsite preservation or 

potential regional mitigation (i.e., 

mitigation locations outside the 

area of impact).

2.3.1.2 Scarcity of Scenic Quality 

Values A, B, and C

Apart from the scenic quality 

rating unit scarcity score, a closer 

examination of individual visual 

resource value (A, B, and C) 

acreages and distribution can also 

provide insight on overall scarcity. 

The quantity and distribution of 

Scenic Quality A, B, and C acreages 

should be assessed and carefully 

examined. The distribution of 

these scenic quality classes within 

the Mojave Desert ecoregion is as 

follows:

1. Scenic Quality A:

653,808 acres (6.7%)

2. Scenic Quality B: 

4,871,253 acres (49.7%)

3. Scenic Quality C: 

4,268,449 acres (43.6%) 

Figure 4: Example - Southern Nevada District visual resource inventory scenic quality scarcity rating map.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 67

This distribution indicates that 

Scenic Quality A is scarce across 

the Mojave Desert ecoregion, 

whereas Scenic Qualities B and C 

are abundant. The Dry Lake SEZ 

is located within an area assigned 

a Scenic Quality C value, which 

indicates scarcity as a nonissue at a 

local and regional scale.

2.3.2 Public Sensitivity Scarcity

The Mojave Desert ecogregion 

public sensitivity values are:

1. High Sensitivity: 

5,840,690 acres (60%)

2. Medium Sensitivity: 

2,239,061 acres (23%)

3. Low Sensitivity: 

1,713,510 acres (17%)

The majority of the region is 

assigned a high public sensitivity 

rating in the VRI, including the 

location of the Dry Lake SEZ. While 

not scarce, this outcome indicates 

that the general public has a high 

regard for the scenic resources 

within these areas and that careful 

consideration should be given 

to the how solar development 

is visually integrated with the 

surrounding landscape character. 

2.3.3 Distance Zone Scarcity

The Mojave Desert ecoregion 

distance zone values are:

1. Foreground/Middle-Ground 

7,394,810 acres (76%)

2. Background:

633,769 acres (6%)

3. Seldom Seen:

1,764,931 acres (18%)

The Dry Lake SEZ is located 

within the Foreground/MiddleGround zone, which contains a 

large majority of the BLM landscape 

within the ecoregion. While scarcity 

is not a factor in respect to the 

distance zone, SEZ development 

will be within the Foreground/

Middle-Ground and within close 

view of the public where the 

noticeability of visual change is 

highest and the visual contrasts are 

typically greatest.

Attention should also be drawn 

to the less abundant distance zones 

of Background and Seldom Seen 

landscapes. The spatial distribution 

of these backcountry settings 

may indicate a scarcity of more 

significance, especially when paired 

up with the other high visual values 

such as Medium to High Sensitivity 

and Scenic Qualities A and B. 

2.3.4 Dry Lake Visual Resource

Inventory Class Scarcity

VRI Classes are determined 

through overlaying the three 

inventoried values (scenic quality, 

sensitivity, and distance zones). 

The combination of the individual 

values assigns VRI Class II, III, or 

IV. The VRI Class assignments are 

derived from the VRI Class Matrix 

where the point of intersection 

between the three values 

determines the VRI Class (see 

Figure 5 and SRMS Tech Reference, 

Appendix F, for a complete 

explanation).

There are 21 possible 

combinations between the three 

visual values. The acreage and 

percent of the SEZ acreage can 

be determined for each of the 21 

combinations of scenic quality/

sensitivity/distance zones to 

diagrammatically illustrate their 

relative commonality or scarcity 

within the ecoregion. 

Approximately 90% of the 

Dry Lake SEZ is inventoried as a 

VRI Class III, while the other 10% 

is VRI Class IV. The visual resource 

values present within the VRI Class 

III boundaries of the Dry Lake SEZ 

include Scenic Quality C, High 

Sensitivity, and Foreground/MiddleGround Distance Zone (Figure 

5). This particular combination 

of values covers 21% of the BLM 

acreage within the Mojave Desert 

ecoregion. Out of 21 possible 

combinations, this specific layering 

of values ranks as the second most 

abundant behind Scenic Quality 

B, High Sensitivity, Foreground/

Middle-Ground. This outcome 

indicates that the Dry Lake SEZ 

is located within an area that has 

common visual values; however, it 

should be noted that even though 

the SEZ contains common visual 

values, there remains high public 

sensitivity within the highly visible 

foreground. Consideration for the 

public sensitivity to visual change 

within the foreground should 

remain a factor when making final 

decisions on whether visual impacts 

may warrant regional mitigation.

The other approximately 

10% of the Dry Lake SEZ that 

was inventoried as VRI Class IV 

includes Scenic Quality C, Medium 

Sensitivity, and Foreground/MiddleGround and represents 8% of the 

BLM acreage within the Mojave 

Desert Ecoregion.
68 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Figure 5. Graphic illustration of the 1998 Las Vegas RMP visual resources management map over the 

Dry Lake Solar Energy Zone visual resource inventory map (Nevada Test Site).

2.4 Visual Resource Resiliency 

There are two aspects 

measured for visual resource 

resilience (see SRMS Technical 

Reference, Appendix F, for more 

information on determining visual 

resource resiliency):

1. Ability of the landscape 

to visually absorb the 

visual change imposed by 

development within the SEZ. 

2. Ability of the landscape to 

visually return to a naturalized 

intact appearance after 

decommissioning the SEZ 

operation.

The Dry Lake SEZ is within the 

Foreground/Middle-Ground and 

immediately contiguous to two 

high-volume highways (U.S. Route 

93 and Interstate 15) from where 

the public would commonly view 

the landscape. The large scale of 

development within the SEZ in 

Dry

Lake

SEZ

proximity of the two highways 

would likely be consistent with 

only the VRM Class IV objective. The 

spatial orientation of the Dry Lake 

SEZ to the casual observer would 

lead to the conclusion that the SEZ 

has no visual resilience. The visual 

resilience at decommissioning 

would be consistent with resilience 

determination for the ecological 

resources of the Mojave Desert 

ecoregion, which has been 

determined to be low resilience.

2.5 Importance Placed on the 

Resource in the Land Use Plan

VRM Class designations are 

made in the land use plan or 

resource management plan, which 

prescribes the allowable degree 

of visual contrast that may be 

created by land use actions on 

BLM-administered lands, including 

energy development activities. 

These decisions establish the 

VRM Class objectives for a given 

parcel of BLM-administered lands 

and are legally binding land use 

decisions requiring conformance 

by all land use actions potentially 

affecting the visual characteristics 

of the landscape. Proposed land 

use actions that are found to 

be out of conformance with the 

VRM objectives are either denied 

approval, modified until they 

demonstrate conformance, or 

require a land use plan amendment 

to change the VRM objectives 

for the lands where the land use 

actions are proposed.

The “Proposed Las Vegas 

Resource Management Plan 

and Final Environmental Impact 

Statement” (Las Vegas RMP) (BLM 

1998) designated the Dry Lake SEZ 

area as VRM Class III and VRM Class 

IV (see Figure 5). The VRM Class III 

allocation sits within the eastern 

half of the SEZ and is bordered by 

and runs parallel to Interstate 15. 

The VRM Class III area is also flanked 

by U.S. Route 93 on the southern 

perimeter of the SEZ. The VRM 

Class IV allocation is located west 

of the VRM Class III area away from 

Interstate 15, but flanked along U.S. 

Route 93.

Given the proximity of the SEZ 

to the heavily traveled Interstate 

15 and U.S. Route 93, it is likely 

that solar development within 

the SEZ would not conform to the 

VRM Class III objective. The VRM 

Class III objective specifies that 

development may be seen and 

may attract visual attention, but 

it must not visually dominate the 

landscape. 

The character and scale of 

facilities and features commonly 

associated with solar development 

located within the foreground 

proximity of the highways 

would likely visually dominate 

the landscape and, thus, would 

not conform with VRM Class III 

requirements. This assumption 

would need to be confirmed 

through the BLM’s formal process 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 69

objectives were developed using 

Appendix F from the SRMS Tech 

Reference (BLM forthcoming). They 

are high-level goals and objectives 

based on the outcome of applying 

the procedures: 

•	 Goal: Restore and/or protect the 

visual resource values altered 

by development of the SEZ 

(taking into account the existing 

condition of visual resource 

values in the Dry Lake SEZ).

•	 Objective: Restore and/or 

protect visual resource values 

proportionate to expected 

impacts in concert with 

ecosystem restoration.

These goals and objectives 

should be carried forward and also 

serve as a framework for identifying 

mitigation location-specific visual 

resource goals and objectives.

2.6.1 Summary of the Basis for 

Visual Resource Regional Mitigation 

Recommendation

Considering the cross-section 

between the general condition 

and trend of the visual values 

reflected in the VRI; scarcity of the 

visual values at the regional scale; 

resilience in the face of change; and 

importance placed on the resource 

in the land use plan, the following 

conclusions were made as a result 

of the aforementioned goal and 

objective in 2.6:

1. General condition and trend 

of the visual values reflected 

in the VRI. The VRI illustrates a 

visual condition of the Mojave 

Desert ecoregion as a landscape 

that is 53% culturally modified 

(visually changed). Given the 

direction of national policy 

promoting the development 

of renewable energy sources 

on BLM-administered lands, 

combined with federal and 

state incentives for encouraging 

the energy industry to invest 

in new renewable energy 

projects, it is reasonable 

to expect a trend toward 

expanded visual change of 

the BLM-administered public 

lands. The Dry Lake SEZ is 

located within a landscape 

that is already modified 

(see Figure 6); however, the 

degree of visual change would 

significantly increase due to 

solar development.

for determining VRM Class objective 

conformance using the Visual 

Contrast Rating System (see BLM 

Handbook H-8431-1). If found to be 

out of conformance with the VRM 

Class III objective, the Las Vegas 

RMP would need to be amended 

so that the entire area available for 

solar energy development within 

the SEZ is VRM Class IV, in order 

to properly permit the proposed 

actions; the VRM Class IV objective 

permits major modification of the 

landscape that may dominate views 

of the project area.

Amending the land use plan 

implies impacting a resource in a 

manner that was not anticipated by 

the prior land use planning process, 

thereby modifying the balance 

among the decisions made on how 

to best manage the visual values 

in relation to other competing 

resource values. Impacting this 

resource to a greater degree than 

previously planned may warrant 

replacing the impaired values in 

suitable areas outside of the impact 

area of the proposed action in order 

to maintain a balanced approach to 

managing the visual resources.

2.6 Regional Visual Mitigation Goals 

and Objectives

The following Dry Lake SEZ 

visual regional mitigation goals and 

Figure 6. Viewing northwest into the Dry Lake Solar Energy Zone from U.S. Route 93
70 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

2. Importance placed on the 

resource in the land use plan. 

Development within the SEZ 

will likely not conform to the 

current Las Vegas RMP VRM 

Class III objective and will need 

amending to allow for a greater 

degree of visual change. The 

SEZ will likely become the 

dominant unnatural visual 

feature within the Dry Lake 

Valley as new solar energy 

facilities are constructed over 

the life of the SEZ. This degree 

of visual change was not 

anticipated in the Las Vegas 

RMP (BLM 1998) and will 

necessitate a rebalancing of the 

management of visual resource 

values. 

3. Scarcity of the visual values 

at the regional scale. The 

SEZ is located within an area 

inventoried as Scenic Quality C 

and represents 43% percent of 

the Mojave Desert ecoregion, 

which would be considered 

a regionally common visual 

value. However, it is paired with 

high public sensitivity and is 

within the visually exposed 

Foreground/Middle-Ground 

distance zone.

4. Resilience in the face of 

change. The landscape 

character where the SEZ is 

located is not conducive to 

visually absorbing the proposed 

scale of solar development 

from where people commonly 

view the landscape, leading 

to the conclusion that there 

would be no resiliency while 

the SEZ is fully operational. The 

landscape the SEZ is located 

within is also very difficult to 

successfully revegetate. A longterm visual footprint will likely 

be left behind and remain over 

a significant period of time after 

the SEZ is decommissioned, 

indicating a low visual 

resilience.

It is recommended that the 

values lost be recovered elsewhere 

through regional mitigation, in 

consideration of (1) the present and 

future change to the landscape’s 

natural character; (2) the SEZ being 

located in the foreground of a 

visually sensitive landscape; (3) 

the visual change anticipated to 

occur within the SEZ being more 

visually dominant than what was 

foreseen within the Las Vegas RMP; 

and (4) the low resilience of the 

landscape during SEZ operation 

and post-decommissioning. 

When factoring the commonality 

of Scenic Quality C and an 

indicator of low scenic quality, the 

recommendation for achieving the 

goal for restoring and/or protecting 

the visual resource values altered 

by development of the SEZ should 

be pursued through a combined 

approach, incorporating the stated 

visual objective into the planning 

and implementation of the regional 

mitigation goals and objectives for 

ecosystem restoration.

This strategy identifies 

the Gold Butte Area of Critical 

Environmental Concern (ACEC) 

as the recommended location for 

regional mitigation of ecological 

resource impacts. The visual values 

within the Gold Butte ACEC are 

higher than those of the Dry Lake 

SEZ, which provides opportunity for 

enhancement or preservation of an 

area regarded as having high visual 

resource value in combination with 

high ecological resource value.

2.6.2 Recommended Mitigation Location 

- Gold Butte Area Visual Resource Values

The visual resource regional 

mitigation objective calls to “restore 

and/or protect visual resource 

values proportionate to expected 

impacts.” Offsetting expected 

impacts that are proportionate 

implies an opportunity for making 

acreage adjustments if the resource 

value lost is replaced with resources 

of higher value (see SRMS Tech 

Reference, Appendix F). 

If ecological restoration and 

preservation activities were to 

occur at the Gold Butte ACEC, 

examination of the visual resource 

values inventoried within the ACEC 

will provide insight on locations 

and will also lead to a combined 

opportunity for recovering visual 

values that are equal to or greater 

in value to those reduced at the Dry 

Lake SEZ. These locations would 

also likely have an increase in public 

benefit.

2.6.2.1 Visual Resource

Inventory Classes. 

There is a mix of VRI Class I, 

II, and III within the Gold Butte 

ACEC, with VRI Class II representing 

approximately 70 percent of the 

area (Figure 7). The Dry Lake SEZ 

is located within a VRI Class III 

and IV area. The majority of the 

Gold Butte ACEC has higher visual 

resource values indicating that any 

resource restoration that visually 

complements the landscape will 

likely have a higher public benefit in 

exchange for the reduction in visual 

values at the Dry Lake SEZ. 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 71

Figure 7. BLM Southern Nevada District visual resource inventory class assignment map.
72 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Scenic Quality. Distribution of 

scenic quality within the Gold Butte 

ACEC is:

•	 Scenic Quality A:

Approximately 60%

•	 Scenic Quality B:

Approximately 30%

•	 Scenic Quality C:

0% (scenic quality for the

Dry Lake SEZ area)

•	 Not inventoried, but within

VRI Class I (wilderness area): 

Approximately 10%

The mix of scenic quality within 

the Gold Butte ACEC (Figure 8) is of 

higher value than what is present at 

the Dry Lake SEZ indicating that any 

resource restoration that visually 

complements the landscape will 

likely have a higher public benefit 

in exchange for the reduction in 

scenic quality at the Dry Lake SEZ.

Figure 8. BLM Southern Nevada District scenic quality rating map illustrating values within the Gold Butte Area of Critical Environmental Concern.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 73

Sensitivity. Distribution of 

sensitivity level within the Gold 

Butte ACEC is:

•	 High Sensitivity: Approximately

80% (public sensitivity for the 

Dry Lake SEZ area)

•	 Medium Sensitivity: 0%

•	 Low Sensitivity:

Approximately 11%

The majority of the Gold 

Butte ACEC is equal to the public 

sensitivity level present at the Dry 

Lake SEZ. Ecological restoration or 

preservation activities should be 

located within the Gold Butte areas 

inventoried as having high public 

sensitivity for scenic quality and 

avoid the 11% of the Gold Butte 

ACEC attributed to having medium 

and low public sensitivity (Figure 

9). Ecological resource restoration 

that visually complements the 

landscape within the 80% area 

assigned high public sensitivity will 

likely have an equal public benefit 

in exchange for the reduction to 

the sensitivity value at the Dry Lake 

SEZ.

Figure 9. BLM Southern Nevada District visual resource inventory sensitivity level rating map illustrating values

within the Gold Butte Area of Critical Environmental Concern.
74 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

Distance Zone. Fifty-nine 

percent of the Gold Butte ACEC 

is within the Foreground/MiddleGround Distance Zone (Figure 10), 

which is the same as the Dry Lake 

SEZ. However, it is worth noting 

that 41% of the acreage inventoried 

within the Background and Seldom 

Seen Distance Zones represents 

a scarcer 24% of the inventoried 

landscape at the regional scale. 

Given the scarce nature of these 

backcountry landscape settings, 

ecological restoration that 

complements the landscapes 

naturalistic character will likely have 

an equal or greater public benefit 

within any of the distance zones 

that are paired with high sensitivity. 

Figure 10. BLM Southern Nevada District visual resource inventory distance zone map.
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 75

VRM Class Objectives: The 

majority of the Gold Butte ACEC is 

designated for management under 

VRM Class II (Figure 11): retention of 

the natural visual characteristics of 

the landscape with minimal visual 

change. This VRM Class is more 

protective of visual values than 

those at the Dry Lake SEZ, which is 

currently managed as VRM Classes 

III and IV.

Figure 11. Visual Resource Management Classes throughout southern Nevada, including the Gold Butte Area of Critical Environmental Concern.

General vicinity of

Gold Butte ACEC
76 • REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444

2.6.2.2 Visual Resource Regional 

Mitigation Recommendations 

In concert with ecological 

mitigation, specifics of the 

visual resource mitigation 

recommendations are:

As the Las Vegas RMP is 

amended from a VRM Class III to a 

VRM Class IV within the Dry Lake 

SEZ area, also consider amending 

the VRM Classes within the Gold 

Butte ACEC involving restoration 

and/or protection of ecological 

resources from a VRM Class II to a 

VRM Class I—preservation of the 

visual resource value to protect the 

investment, outcome, and integrity 

of the ecological and visual regional 

mitigation actions.

If the ecological mitigation 

includes surface restoration, then 

sound visual design practices 

should be included as a part 

of the restoration planning, 

with the participation of the 

Southern Nevada District Office 

VRM lead (see the 2013 edition 

of “Best Management Practices 

for Reducing Visual Impacts of 

Renewable Energy Facilities on 

BLM-Administered Lands,” available 

at http://www.blm.gov/style/

medialib/blm/wo/MINERALS__

REALTY__AND_RESOURCE_

PROTECTION_/energy/renewable_

references.Par.1568.File.dat/

RenewableEnergyVisualImpacts_

BMPs.pdf). 

Ecological resource restoration 

plans should demonstrate the 

visual resource benefits that will 

be accomplished. The BLM’s visual 

contrast rating process should 

be used along with descriptive 

narrative to demonstrate how the 

improvements will reflect enhanced 

scenic resource values within the 

VRI. The inventory should then be 

updated reflecting the positive 

change. The VRI demonstrates the 

opportunity to replace the values 

reduced at the Dry Lake SEZ by 

restoring or protecting higher 

values in the Gold Butte ACEC that 

would have greater public benefit. 

2.7 Specially Designated Areas

As discussed in 2.0 of this 

appendix, a second consideration 

of unavoidable visual resource 

impact is to evaluate how the 

change within the SEZ will affect 

important viewsheds from lands 

with legislated protection for 

scenery and/or landscape settings, 

which may include, but are not 

limited to, the following specially 

designated areas:

a. National parks. 

b. National wildlife refuges.

c. Wilderness areas. 

d. National scenic and historic 

trails. 

e. Special recreation 

management areas.

2.7.1 Dry Lake Solar Energy Zone 

Development Visibility from Nearby 

Specially Designated Areas

For the Final Solar PEIS, a 

preliminary analysis was conducted 

of the potential contrasts that 

might be created by solar 

development in the SEZ, as seen 

from specially designated areas 

that are visible from and within 

25 mi of the SEZ. The analysis 

was conducted by constructing 

virtual computer models of the 

most visually impacting solar 

development technology (solar 

power towers) located within the 

Dry Lake SEZ. 

The determination of 

unavoidable visual impacts is based 

on the Final Solar PEIS analysis and 

further evaluates those specially 

designated areas listed in the Final 

Solar PEIS as having moderate or 

strong visual contrast. The goal is 

to preliminarily identify if these 

impacts are unavoidable and, if 

so, if they may warrant further 

mitigation. 

For the Dry Lake SEZ, the 

specially designated areas of 

concern include:

1. The Desert National Wildlife 

Refuge. 

2. Old Spanish National Historic 

Trail. 

3. Arrow Canyon Wilderness. 

4. Nellis Dunes Special Recreation 

Management Area.

An exercise was conducted 

using Google Earth to:

•	 Reevaluate the impacted

viewshed as delineated in the 

Final Solar PEIS.

•	 Identify potential places where

people may be found recreating 

or conducting other activities 

within the affected viewshed.

•	 Evaluate the full field of view

from locations where people are 

likely to view the SEZ.

•	 Evaluate the influence of the

Visual Contrast Rating System 10 

environmental factors (see BLM 

Handbook H-8431-1, II.D.2.b) on 

the degree of impact on specially 

designated area observers.

2.7.2 Specially Designated Area 

Unavoidable Impact Visual Impact 

Findings

2.7.2.1 Desert National

Wildlife Refuge

The evaluation concluded 

that the Dry Lake SEZ is not within 

view from locations observers are 

known to be within the Desert 

National Wildlife Refuge. According 

to information provided by the 
 REGIONAL MITIGATION STRATEGY FOR THE DRY LAKE SOLAR ENERGY ZONE • TECHNICAL NOTE 444 • 77

Desert National Wildlife Refuge, 

the majority of refuge visitation 

originates at the visitor center, with 

visitors accessing other areas of 

interest using the refuge’s network 

of roads and trails. Views of the Dry 

Lake SEZ from the refuge’s visitor 

center and network of roads and 

trails are obstructed by either the 

Sheep Range and/or the Las Vegas 

Range, which are west of the SEZ.

2.7.2.2 Old Spanish

National Historic Trail

According to the BLM Pahrump 

Field Office archaeologist, the Old 

Spanish National Historic Trail is 

east of the Dry Lake SEZ and lies 

within the Dry Lake Range. The trail 

roughly runs parallel to Interstate 

15 with views of the Dry Lake SEZ 

being obstructed by topography 

within the Dry Lake Range.

2.7.2.3 Arrow Canyon

Wilderness Area 

The areas within the Arrow 

Canyon Wilderness known to 

have high visitation include the 

slot canyons from which the 

development within the SEZ will 

not be visible. Nevertheless, it is 

likely that dispersed recreation 

activities will draw observers to 

higher elevations that overlook the 

Dry Lake valley.

The Final Solar PEIS viewshed 

analysis illustrates an estimated 

distance range of 9 to 22 mi from 

Arrow Canyon to the Dry Lake 

SEZ, with 4% percent (1,011 acres) 

of the total area of the Arrow 

Canyon Wilderness Area as having 

unobstructed views of the SEZ 

within the 5 to 15 mile range, with 

another 1% of the area (204 acres) 

within the 15 to 25 mile range. 

While views of the solar energy 

development may be seen, it is 

unlikely that the visual dominance 

will be greater than a VRM Class 

III objective (moderate levels of 

change may be seen and draw the 

attention of the casual observer, 

but the change does not dominate 

the landscape). This would be a 

worst case scenario from the closer 

proximities to the Dry Lake SEZ. The 

exposure within these areas is very 

intermittent. 

The SEZ is visible from a very 

small portion of the Arrow Canyon 

Wilderness, and where visible, 

impacts from solar development 

within the SEZ are expected to be 

low; therefore, regional mitigation is 

not warranted.

2.7.2.4 Nellis Dunes Special 

Recreation Management Area

The Nellis Dunes Special 

Recreation Management Area 

is a popular off-highway vehicle 

area. The SEZ is visible from 412 

acres (5%) of the Nellis Dunes, 

and where visible, impacts from 

solar development within the SEZ 

are expected to be negligible; 

therefore, regional mitigation is not 

warranted.

2.7.2.5 Conclusions

Unavoidable visual impacts to 

the specially designated areas are 

low with no recommendations for 

regional mitigation.