Federal Energy

Regulatory

Commission

Swan Falls Hydroelectric Project

Idaho

(FERC Project No. 503-048)

888 First Street N.E., Washington, DC 20426

Draft

Environmental Impact Statement

FERC/DEIS – 0234

March 2010

Office of

Energy

Projects
FEDERAL ENERGY REGULATORY COMMISSION 

WASHINGTON, DC 20426 

OFFICE OF ENERGY PROJECTS 

To the Agency or Individual Addressed: 

Reference: Draft Environmental Impact Statement

Attached is the draft environmental impact statement (draft EIS) for the Swan 

Falls Project (FERC Project No. 503-048), located on the Snake River in Ada and 

Owyhee counties, Idaho. 

This draft EIS documents the view of governmental agencies, non-governmental 

organizations, affected Indian tribes, the public, the license applicant, and Federal Energy 

Regulatory Commission (Commission) staff. It contains staff evaluations of Idaho Power 

Company’s proposal and the alternatives for relicensing the Swan Falls Project. 

You are invited to file comments on the DEIS. Any comments, conclusions, or 

recommendations that draw upon studies, reports, or other working papers should be 

supported by appropriate documentation. Your comments will be considered in the 

staff’s preparation of the final EIS. 

Comments should be filed with: Kimberly D. Bose, Secretary, Federal Energy 

Regulatory Commission, 888 First Street, NE, Washington, DC 20426. All comments 

must be filed within 45 days of the notice date in the Federal Register and should 

reference Project No. 503-048. Comments may be filed electronically via the Internet in 

lieu of paper. The Commission strongly encourages electronic filings. See 18 CFR 

385.2001(a)(1)(iii) and the instructions on the Commission’s web site (www.ferc.gov) 

under the “e-Filing” link. 

Before the Commission makes a licensing decision, it will take into account all 

concerns relevant to the public interest. The draft EIS will be part of the record from 

which the Commission will make its decision. The draft EIS was sent to the U.S. 

Environmental Protection Agency and made available to the public in March 2010. 

Copies of the draft EIS are available for review in the Commission’s Public 

Reference Branch, Room 2A, located at 888 First Street, N.E., Washington, DC 20426. 

The draft EIS also may be viewed on the Internet at www.ferc.gov/docsfiling/elibrary.asp. Please call (202) 502-8222 for assistance. 

Attachment: Draft Environmental Impact Statement 
COVER SHEET 

a. Title: Relicensing the Swan Falls Hydroelectric Project, FERC Project 

No. 503-048 

b. Subject: Draft Environmental Impact Statement 

c. Lead Agency: Federal Energy Regulatory Commission 

d. Abstract: On June 26, 2008, Idaho Power Company filed an application for 

license with the Federal Energy Regulatory Commission 

(Commission) for a new license for the 25-megawatt Swan Falls 

Hydroelectric Project (project), FERC No. 503-048, located on the 

Snake River in Ada and Owyhee counties, Idaho, about 35 miles 

southwest of Boise. 

The project currently occupies 529 acres of federal lands 

administered by the Bureau of Land Management. 

The staff’s recommendation is to relicense the project as proposed, 

with certain modifications and additional measures recommended 

by the agencies and the staff to protect and enhance environmental 

resources. 

e. Contact: James Puglisi 

Federal Energy Regulatory Commission 

Office of Energy Projects 

888 First Street, N.E. 

Washington, DC 20426 

(202) 502-6241 

f. Transmittal: This draft environmental impact statement prepared by the 

Commission staff for the Swan Falls Hydroelectric Project is being 

made available for public comment in March 2010, as required by 

the National Environmental Policy Act of 19691

 and the 

Commission’s Regulations Implementing the National 

Environmental Policy Act (18 CFR, Part 380). 

 

1

 National Environmental Policy Act of 1969, amended (Pub. L. 91-190. 42 U.S.C. 

4321-4347, January 1, 1970, as amended by Pub. L. 94-52, July 3, 1975, Pub. L. 94-83, 

August 9, 1975, and Pub. L. 97-258, §4(b), September 13, 1982). 
FOREWORD 

The Federal Energy Regulatory Commission (Commission), pursuant to the 

Federal Power Act (FPA)2

 and the U.S. Department of Energy Organization Act3 is 

authorized to issue licenses for up to 50 years for the construction and operation of nonfederal hydroelectric development subject to its jurisdiction, on the necessary conditions: 

That the project...shall be such as in the judgment of the Commission will be best 

adapted to a comprehensive plan for improving or developing a waterway or waterways 

for the use or benefit of interstate or foreign commerce, for the improvement and 

utilization of water-power development, for the adequate protection, mitigation, and 

enhancement of fish and wildlife (including related spawning grounds and habitat), and 

for other beneficial public uses, including irrigation, flood control, water supply, and 

recreational and other purposes referred to in section 4(e)...4

The Commission may require such other conditions not inconsistent with the FPA 

as may be found necessary to provide for the various public interests to be served by the 

project.5

 Compliance with such conditions during the licensing period is required. The 

Commission’s Rules of Practice and Procedure allow any person objecting to a licensee’s 

compliance or noncompliance with such conditions to file a complaint noting the basis 

for such objection for the Commission’s consideration.6

 

2

 16 U.S.C. §791(a)-825r, as amended by the Electric Consumers Protection Act of 

1986, Pub. L. 99-495 (1986), the Energy Policy Act of 1992, Pub. L. 102-486 (1992), and 

the Energy Policy Act of 2005, Pub. L. 109-58 (2005). 

3

 Pub. L. 95-91, 91 Stat. 556 (1977). 

4

 16 U.S.C. § 803(a). 

5

 16 U.S.C. § 803(g). 

6

 18 C.F.R. §385.206 (2009). 
v 

TABLE OF CONTENTS 

LIST OF FIGURES ............................................................................................................ ix

LIST OF TABLES ............................................................................................................... x

ACRONYMS AND ABBREVIATIONS ........................................................................... xi

EXECUTIVE SUMMARY .............................................................................................. xiii

1.0 INTRODUCTION .................................................................................................... 1

1.1 APPLICATION ............................................................................................. 1

1.2 PURPOSE OF ACTION AND NEED FOR POWER .................................. 1

1.2.1 Purpose of Action ............................................................................ 1

1.2.2 Need for Power ................................................................................ 3

1.3 STATUTORY AND REGULATORY REQUIREMENTS ......................... 4

1.3.1 Federal Power Act ........................................................................... 5

1.3.1.1 Section 18 Fishway Prescriptions ................................... 5

1.3.1.2 Section 10(j) Recommendations ..................................... 5

1.3.2 Clean Water Act .............................................................................. 5

1.3.3 Endangered Species Act .................................................................. 6

1.3.4 National Historic Preservation Act .................................................. 6

1.3.5 Pacific Northwest Power Planning and Conservation Act .............. 7

1.4 PUBLIC REVIEW AND CONSULTATION ............................................... 8

1.4.1 Scoping ............................................................................................ 8

1.4.2 Interventions .................................................................................... 9

1.4.3 Comments on the License Application ........................................... 9

2.0 PROPOSED ACTION AND ALTERNATIVES ................................................... 11

2.1 NO-ACTION ALTERNATIVE .................................................................. 11

2.1.1 Existing Project Facilities .............................................................. 11

2.1.2 Project Boundary ........................................................................... 11

2.1.3 Project Safety ................................................................................. 11

2.1.4 Existing Project Operation ............................................................ 12

2.1.5 Existing Environmental Measures ................................................. 12

2.2 APPLICANT’S PROPOSAL ...................................................................... 13

2.2.1 Proposed Project Facilities and Boundary Modifications ............. 13

2.2.2 Proposed Project Operation ........................................................... 14

2.2.3 Proposed Environmental Measures ............................................... 14

2.2.4 Modifications to Applicant’s Proposal—Mandatory Conditions .. 17

2.3 STAFF ALTERNATIVE ............................................................................ 17

2.4 ALTERNATIVES CONSIDERED BUT ELIMINATED FROM 

FURTHER ANALYSIS .............................................................................. 19

2.4.1 Issuing a Non-power License ........................................................ 19
vi 

2.4.2 Federal Government Takeover of the Project ............................... 19

2.4.3 Retiring the Project ........................................................................ 19

3.0 ENVIRONMENTAL ANALYSIS ......................................................................... 21

3.1 GENERAL DESCRIPTION OF THE RIVER BASIN .............................. 21

3.2 SCOPE OF CUMULATIVE EFFECTS ANALYSIS ................................ 22

3.2.1 Geographic Scope .......................................................................... 23

3.2.2 Temporal Scope ............................................................................. 23

3.3 PROPOSED ACTION AND ACTION ALTERNATIVES ....................... 23

3.3.1 Geology and Soil Resources .......................................................... 24

3.3.1.1 Affected Environment ................................................... 24

3.3.1.2 Environmental Effects .................................................. 25

3.3.2 Aquatic Resources ......................................................................... 26

3.3.2.1 Affected Environment ................................................... 26

3.3.2.2 Environmental Effects .................................................. 37

3.3.2.3 Cumulative Effects ....................................................... 45

3.3.3 Terrestrial Resources ..................................................................... 45

3.3.3.1 Affected Environment ................................................... 45

3.3.3.2 Environmental Effects .................................................. 55

3.3.3.3 Cumulative Effects ....................................................... 71

3.3.4 Threatened and Endangered Species ............................................. 72

3.3.4.1 Affected Environment ................................................... 72

3.3.4.2 Environmental Effects .................................................. 73

3.3.5 Recreation Resources .................................................................... 74

3.3.5.1 Affected Environment ................................................... 74

3.3.5.2 Environmental Effects .................................................. 81

3.3.6 Land Use and Aesthetic Resources ............................................... 93

3.3.6.1 Affected Environment ................................................... 93

3.3.6.2 Environmental Effects .................................................. 99

3.3.7 Cultural Resources ....................................................................... 105

3.3.7.1 Affected Environment ................................................. 105

3.3.7.2 Environmental Effects ................................................ 116

3.3.8 Socioeconomics ........................................................................... 128

3.3.8.1 Affected Environment ................................................. 128

3.3.8.2 Environmental Effects ................................................ 129

3.4 NO-ACTION ALTERNATIVE ................................................................ 129

4.0 DEVELOPMENTAL ANALYSIS ...................................................................... 131

4.1 POWER AND ECONOMIC BENEFITS OF THE PROJECT ................ 131

4.2 COMPARISON OF ALTERNATIVES .................................................... 133

4.2.1 No-action Alternative .................................................................. 133

4.2.2 Idaho Power’s Proposal ............................................................... 133

4.2.3 Staff Alternative .......................................................................... 134
vii 

4.3 COST OF ENVIRONMENTAL MEASURES ........................................ 134

5.0 CONCLUSIONS AND RECOMMENDATIONS ............................................... 143

5.1 COMPARISON OF ALTERNATIVES .................................................... 143

5.2 COMPREHENSIVE DEVELOPMENT AND RECOMMENDED 

ALTERNATIVE ....................................................................................... 145

5.3 UNAVOIDABLE ADVERSE EFFECTS ................................................. 156

5.4 FISH AND WILDLIFE AGENCY RECOMMENDATIONS ................. 157

5.5 CONSISTENCY WITH COMPREHENSIVE PLANS ............................ 160

6.0 LITERATURE CITED ......................................................................................... 163

7.0 LIST OF PREPARERS ........................................................................................ 175

8.0 LIST OF RECIPIENTS ........................................................................................ 177

APPENDIX A—Idaho Department of Environmental Quality Clean Water Act Section 

401 Water Quality Certification 
ix 

LIST OF FIGURES 

Figure 1. Location of the Swan Falls Hydroelectric Project ...................................................2

Figure 2. Map of the Swan Falls to Brownlee reach of the Snake River ..............................32

Figure 3. Recreational opportunities in the area of the Swan Falls Project ..........................78

Figure 4. Location of dispersed recreational sites proposed for improvements ....................85
x 

LIST OF TABLES 

Table 1. Major statutory and regulatory requirements for the Swan Falls Hydroelectric 

Project ......................................................................................................................4 

Table 2. Estimated inflows for the Swan Falls Project (water years 1913–2006) ...............28 

Table 3. Water quality impaired segments of the Snake River between Shoshone Falls and 

Brownlee dam ........................................................................................................29 

Table 4. Estimated phosphorus loadings from tributaries and point sources to the Snake 

River between the C.J. Strike and Brownlee dams ................................................31 

Table 5. Fish species collected in the project area during fisheries sampling conducted by 

Idaho Power ...........................................................................................................35 

Table 6. Noxious and invasive non-native weed species documented in the Swan Falls 

study area and within or adjacent to the project boundary ....................................47 

Table 7. Special status plant species documented in the Swan Falls study area and within 

the project boundary ..............................................................................................49 

Table 8. Species groups used to evaluate the effects of project-related activities in the 

Swan Falls study area .............................................................................................53 

Table 9. Special status species that could be affected by project operations .......................54 

Table 10. Summary of the Form 80 report for the Swan Falls Project in 2001 .....................79 

Table 11. Current land use within the Swan Falls Project boundary .....................................95 

Table 12. Ownership of lands located within the current and proposed project boundary ..101 

Table 13. Archaeological and historic resources within the Swan Falls Project APE .........114 

Table 14. Population characteristics of Ada County, Owyhee County, and Idaho ..............128 

Table 15. Parameters for the economic analysis of the Swan Falls Project .........................132 

Table 16. Summary of annual costs and annual power benefits for the alternatives for the 

Swan Falls Hydroelectric Project .........................................................................134 

Table 17. Cost of environmental mitigation and enhancement measures considered in 

assessing the environmental effects of continuing to operate the Swan Falls 

Hydroelectric Project ...........................................................................................135 

Table 18. Fish and wildlife agency recommendations for the Swan Falls Hydroelectric 

Project ..................................................................................................................158 
xi 

ACRONYMS AND ABBREVIATIONS 

Advisory Council Advisory Council on Historic Preservation 

AIR additional information request 

APE area of potential effects 

applicant Idaho Power Company 

Archaeological District Guffey Butte-Black Butte Archaeological District 

BLM Bureau of Land Management 

BP before present 

CFR code of federal regulations 

cfs cubic feet per second 

Commission Federal Energy Regulatory Commission 

DO dissolved oxygen 

EIS environmental impact statement 

oC degrees Celsius 

FERC Federal Energy Regulatory Commission 

FERC Form 80 Licensed Hydropower Development Recreation Report 

Forest Service U.S. Department of Agriculture, Forest Service 

FPA Federal Power Act 

FWS U.S. Department of the Interior, Fish and Wildlife Service 

GIS Geographic Information Systems 

HAER Historic American Engineering Record 

HPMP Historic Properties Management Plan 

Idaho DEQ Idaho Department of Environmental Quality 

Idaho DFG Idaho Department of Fish and Game 

Idaho DPR Idaho Department of Parks and Recreation 

Idaho Power Idaho Power Company 

Idaho SHPO Idaho State Historic Preservation Officer 

Interior U.S. Department of the Interior 

KOP key observation point 

mg/L milligram per liter 

msl mean sea level 

MW megawatt 

MWh megawatt-hour 

National Register National Register of Historic Places 

NCA National Conservation Area 

NERC North American Electric Reliability Corporation 

OHWM ordinary high water mark 

NHPA National Historic Preservation Act of 1966 

PA programmatic agreement 

Program Columbia River Basin Fish and Wildlife Program 

project Swan Falls Hydroelectric Project 

REA Ready for Environmental Analysis 
xii 

Reclamation U.S. Bureau of Reclamation 

Refuge Deer Flat National Wildlife Refuge 

RM river mile 

§ section 

SCORP Statewide Comprehensive Outdoor Recreation Plan 

SCORTP Statewide Comprehensive Outdoor Recreation and Tourism 

Plan 

SD1 Scoping Document 1 

Shoshone-Bannock Shoshone-Bannock Tribes of the Fort Hall Reservation 

Tribes 

TCP traditional cultural property 

TDG total dissolved gas 

TMDL total maximum daily load 

USGS U.S. Geological Survey 

VRM visual resource management 

WQC water quality certification 

WSTAC White Sturgeon Technical Advisory Committee 
xiii 

EXECUTIVE SUMMARY 

This draft environmental impact statement (draft EIS) evaluates the potential 

natural resource benefits, environmental impacts, and economic costs associated with 

relicensing the existing 25-megawatt Swan Falls Hydroelectric Project (project), located 

on the Snake River in Ada and Owyhee counties, Idaho, about 35 miles southwest of 

Boise. The project occupies 529 acres of federal lands administered by the Bureau of 

Land Management (BLM). 

Proposed Action 

The existing project is composed of a concrete dam, a concrete spillway having 12 

spillway gates, a concrete powerhouse integral with the dam, a switchyard, and two 

transmission lines; it is described in more detail in section 2.2, Applicant’s Proposal. 

Idaho Power Company (Idaho Power) proposes no capacity changes and proposes to 

continue the ongoing operations of the project with a change in the minimum flow regime 

to provide instantaneous minimum flows of 3,900 cubic feet per second (cfs) from April 

1 to October 31 each year, and 5,600 cfs from November 1 to March 31, and continuation 

of the existing ramping rate restrictions of no more than 1 foot per hour and 3 feet per 

day. Other proposals by Idaho Power include: monitoring water temperature and 

dissolved oxygen (DO) in the project outflow; monitoring the resident fish population; 

implementing the Wildlife Habitat and Enhancement Plan, Noxious Weed Management 

Plan, Special Status Management Plan, Recreation Management Plan, Visual Guidelines 

Plan, and Historic Properties Management Plan (HPMP); and preparing and 

implementing a transmission line operation and maintenance plan. 

Alternatives Considered 

This EIS analyzes the effects of continued project operation and recommends 

conditions for a new license for the project. In addition to Idaho Power’s proposal, we 

consider two alternatives: (1) the staff alternative, and (2) no action—continued 

operation under the terms and conditions of the existing license, with no new 

environmental measures implemented. 

Under the staff alternative, the project would be operated to include most of the 

measures proposed by Idaho Power, as well as measures recommended by the Federal 

Energy Regulatory Commission (Commission) staff. The recommended staff 

modifications include or are based in part on recommendations made by the federal and 

state resource agencies that have an interest in the resources that may be affected by 

continued project operation. 

Aquatic Resources 

• Develop and implement a plan with provisions to monitor the following water 

quality parameters as stipulated in Idaho DEQ’s WQC: (1) water temperature 

and DO in the project's outflow throughout the term of any issued license; (2) 
xiv 

water temperature and DO in the project's inflow for at least 5 years after 

issuance of any license; and (3) TDG and discharge in the project's inflow and 

outflow for at least 5 years after issuance of any license. Develop a quality 

assurance control plan; submit annual data reports to Idaho DEQ and the 

Commission; and prepare and file a report with the Commission with a copy to 

Idaho DEQ summarizing the results of the first 5 years of monitoring, and 

describing any proposed changes to the monitoring program. 

Terrestrial Resources 

• Implement timing restrictions on transmission line maintenance activities, as 

needed, to protect benchland nesters and cliff-nesting raptors. 

Recreation Resources 

• Revise and implement the Recreation Management Plan to include: (1) 

completion of Idaho Power’s consultation with the Idaho State Historic 

Preservation Officer (Idaho SHPO) to ensure that work planned at informal 

dispersed recreation sites and associated access roads considers the effects on 

cultural resources known to exist in the area; (2) soil erosion control measures; 

(3) detailed design drawings of Swan Falls Park, Swan Falls reservoir boat 

ramp, Swan Falls downstream boat launch, and the canoe portage trail; (4) a 

description of improvements to the six dispersed recreation sites; (5) a 

discussion on how the needs of the disabled were considered in the planning 

and design of the recreation facilities; (6) an implementation schedule; (7) 

modification of the Litter and Sanitation Plan so that it applies only to lands 

within the project boundary; and (8) finalization and implementation of the 

Interpretation and Education Plan as part of the Recreation Management Plan 

in consultation with BLM, Idaho Department of Parks and Recreation (Idaho 

DPR), and Idaho SHPO. 

• Establish an interagency recreation working group that convenes every 6 years 

in coordination with preparing the FERC Form 807

 to assess recreation 

facilities, dispersed recreation sites, and usage. 

Land Use and Aesthetic Resources 

• Revise the proposed Visual Guidelines Plan to include a list of neutral paint 

color schemes, a list of vegetation species for vegetation, a list of construction 

materials that could be used, and documentation of consultation with BLM and 

Idaho DPR. 

 

7

 Licensed Hydropower Development Recreation Report—Form 80. 
xv 

Cultural Resources 

• Revise the December 2008 HPMP to include a program for immediate 

implementation of mitigation measures for sites being affected by shoreline 

erosion or vandalism, as well as sites proposed for recreation improvements. 

Include consultation among Idaho Power, Idaho SHPO, BLM, and 

participating tribes to formulate site-specific mitigation measures. The 

anticipated programmatic agreement (PA) would incorporate the HPMP. 

Public Involvement and Areas of Concern 

Before filing its license application, Idaho Power conducted pre-filing consultation 

under the Commission’s traditional licensing process. The Commission’s pre-filing 

process initiates public involvement early in the project planning process and encourages 

citizens, governmental entities, tribes, and other interested parties to identify and resolve 

issues before an application is formally filed with the Commission. After the application 

was filed, we conducted scoping to determine which issues and alternatives should be 

addressed. Scoping Document 1 (SD1) was distributed to interested parties on January 9, 

2009. Scoping meetings were held in Boise, Idaho, on February 10 and 11, 2009, and a 

site visit of the project area was conducted by Idaho Power, resource agency personnel, 

interested parties, and Commission staff on February 10, 2009. In SD1, we requested 

clarification of preliminary issues concerning the Swan Falls Project and identification of 

any new issues that need to be addressed in the EIS. A revised scoping document 

addressing these comments was issued on May 5, 2009. On June 16, 2009, we requested 

conditions and recommendations in response to the Commission’s Ready for 

Environmental Analysis notice. 

Important issues we address include the effects of project operation and 

maintenance on water quality and white sturgeon, as well as the effects of project 

operation, project maintenance, and recreational use of the area within and near the 

project boundary on terrestrial and cultural resources. 

Project Effects 

Geology and Soils 

Under Idaho Power’s proposal and the staff alternative, Idaho Power would reduce 

erosion by restoring approximately 79 acres of land and 2.7 miles of riparian shoreline, 

formalizing recreational access and use areas, and eliminating informal recreational 

access and use in areas where Idaho Power proposes additional resource protection. 

Aquatic Resources 

Under Idaho Power’s proposal, continued removal of aquatic vegetation and 

debris that accumulates on the trash racks would remove nutrients from the river, helping 

to improve water quality, and monitoring of water temperature and DO in the project 
xvi 

tailrace would help to confirm that project operations, including proposed minimum flow 

release changes, would not adversely affect short- or long-term water quality. Under the 

staff alternative, monitoring discharge, water temperature, DO and TDG of the project 

inflow and outflow would help better define any project effects on water quality over a 

range of hydrologic and meteorological conditions, and would help to determine whether 

any additional measures are warranted to address project effects on water resources. 

Under Idaho Power’s proposal, implementation of a resident fish population 

monitoring program would determine basic population characteristics. However, because 

the proposed monitoring is not designed to detect for the effects of any specific projectrelated action, the monitoring program is not included in the staff alternative. 

Terrestrial Resources 

Implementation of Idaho Power’s proposed Wildlife Habitat Protection and 

Enhancement Plan would improve conditions for numerous wildlife species in the project 

area that use riparian habitat and would also improve conditions in project area uplands. 

Idaho Power’s proposed Special Status Plant Management Plan would provide an 

effective means of protecting these species from recreational activity where they occur 

within the project boundary. Implementation of Idaho Power’s Noxious Weed 

Management Plan would promote native plant communities that provide higher quality 

habitat for wildlife than those dominated by invasive non-native species. 

However, measures to protect soils and botanical resources in both a transmission 

line operation and maintenance plan and the Noxious Weed Management Plan would be 

duplicative, and implementation of the Noxious Weed Management Plan alone would 

ensure the protection of soils and botanical resources on all project lands, including the 

transmission line right-of-way. Therefore, under the staff alternative a transmission line 

operation and maintenance plan would not be necessary. Instead, the staff alternative 

would include timing restrictions on transmission line maintenance activities to minimize 

the risk of disturbing benchland nesters and cliff-nesting raptors during the 

breeding season. 

Threatened and Endangered Species 

Under both Idaho Power’s proposal and the staff alternative, effects on the Snake 

River physa from stranding and desiccation due to changes in water levels would 

continue to be very low. 

Recreation 

Under Idaho Power’s proposal, recreational opportunities would be improved as a 

result of finalizing and implementing the draft Recreation Management Plan, which 

includes continuing operation, maintaining the existing five project recreational facilities, 

continuing implementation of Idaho Power’s public safety program, upgrading existing 

facilities, improving six dispersed recreation sites, adding to interpretive and 
xvii 

informational displays, and implementing the Litter and Sanitation Plan at areas both 

inside and outside the project boundary. 

Under the staff alternative, staff’s recommendation for revising the Recreation 

Management Plan to include additional staff recommendations and consultation with 

Idaho DPR, Idaho Department of Fish and Game (Idaho DFG), Idaho SHPO, and BLM 

would ensure that the potential adverse effects of recreational development and use on 

cultural and terrestrial resources would be appropriately considered. Additionally, the 

Litter and Sanitation Plan would apply only to lands within the project boundary. 

Land Use and Aesthetics 

Under both Idaho Power’s proposal and the staff alternative, there would be a 

reduction of 599 acres within the project boundary. The proposed project boundary 

modifications would remove 791 acres of project land upstream and downstream of the 

Swan Falls dam that are not needed for project purposes, and add 192 acres of project 

land downstream of the dam to incorporate restored lands8

 as part of the Wildlife Habitat 

and Protection Enhancement Plan, cultural resource sites requiring long-term monitoring, 

and dispersed recreation sites proposed for improvement.

Idaho Power’s proposal would provide some protection to visual resources under 

the provisions of the Visual Guidelines Plan. The staff alternative includes additional 

recommendations and coordination with BLM and Idaho DPR.

Cultural Resources 

Under Idaho Power’s proposal, cultural resources would be protected under 

provisions specified in the HPMP filed with the Commission in December 2008. 

However, the December 2008 HPMP does not address mitigating the effects on the 10 

archaeological sites subject to severe erosion, archaeological sites that would be affected 

by proposed recreation improvements to existing dispersed sites and associated access 

roads (including closure/revegetation of other dispersed sites and roads), and other 

archaeological sites on Idaho Power lands that are being disturbed by vandalism and 

looting associated with recreational use. 

Under the staff alternative, revision of the HPMP to address these project-related 

effects would ensure that all existing and potential future adverse effects on historic 

properties would be adequately addressed over the term of any new license. The revised 

HPMP would be filed with the Commission prior to license issuance, and upon license 

issuance the revised HPMP would be implemented through execution of a PA for a 

new license. 

 

8

 Restored lands refer to the closure of braided roads and nine dispersed recreation 

sites that would be located within the project boundary and would be revegetated as part 

of the Wildlife Habitat and Enhancement Plan. 
xviii 

Socioeconomics 

Idaho Power’s proposal and the staff alternative would provide essentially the 

same socioeconomic benefits as under current conditions. 

Under the no-action alternative, environmental conditions would remain the same 

and no enhancement of environmental resources would occur. 

Conclusions 

Based on our analysis, we recommend relicensing the project as proposed by 

Idaho Power with some staff modifications and additional measures, as described above 

under Alternatives Considered. 

In section 4.1, Power and Economic Benefits of the Project, we estimate the likely 

cost of alternative power for each of the three alternatives identified above. Our analysis 

shows that during the first year of operation under the no-action alternative, project 

power would cost $2,121,430, or $13.15/megawatt-hour (MWh), less than the likely 

alternative cost of power. Under the proposed action alternative, project power would 

cost $1,571,830, or $9.74/MWh, less than the likely alternative cost of power. Under the 

staff alternative, project power would cost $1,561,530, or $9.68/MWh, less than the 

likely alternative cost of power. 

We chose the staff alternative as the preferred alternative because under it: (1) the 

project would provide a dependable source of electrical energy for the region (161,300 

MWh annually); (2) the project would save the equivalent amount of fossil fueled 

generation and capacity; and (3) the recommended environmental measures would 

protect and enhance environmental and cultural resources affected by the project. The 

overall benefits of the staff alternative would be worth the additional costs of the 

recommended environmental measures. 
1 

DRAFT ENVIRONMENTAL IMPACT STATEMENT 

Federal Energy Regulatory Commission 

Office of Energy Projects 

Division of Hydropower Licensing 

Washington, DC 

Swan Falls Hydroelectric Project 

FERC Project No. 503-048—Idaho 

1.0 INTRODUCTION 

1.1 APPLICATION 

On June 26, 2008, Idaho Power Company (Idaho Power or applicant) filed an 

application for a new license with the Federal Energy Regulatory Commission 

(Commission or FERC) for the 25-megawatt (MW) Swan Falls Hydroelectric Project 

(Swan Falls Project or project), FERC No. 503-048. The project is located on the Snake 

River in Ada and Owyhee counties, Idaho, about 35 miles southwest of Boise (figure 1). 

The project currently occupies 529 acres9

 of federal lands administered by the Bureau of 

Land Management (BLM). The project generates an average of about 161,300 

megawatt-hours (MWh) of energy annually. Idaho Power proposes no new capacity and 

no new construction. 

1.2 PURPOSE OF ACTION AND NEED FOR POWER 

1.2.1 Purpose of Action 

The Commission must decide whether to issue a license to Idaho Power for the 

Swan Falls Project and what conditions should be placed on any license issued. In 

deciding whether to issue a license for a hydroelectric project, the Commission must 

determine that the project will be best adapted to a comprehensive plan for improving or 

developing a waterway. In addition to the power and developmental purposes for which 

licenses are issued (such as flood control, irrigation, or water supply), the Commission 

must give equal consideration to the purposes of: (1) energy conservation; (2) the 

protection of, mitigation of damage to, and enhancement of fish and wildlife resources; 

(3) the protection of recreational opportunities; and (4) the preservation of other aspects 

of environmental quality.

 

9 The federal land acreage is based on Idaho Power’s Technical Report Appendix 

E.6-B (Johnson, 2008). 
2 

Figure 1. Location of the Swan Falls Hydroelectric Project (Source: Idaho Power, 2008a, as modifi
3 

Issuing a new license for the Swan Falls Project would allow Idaho Power to 

generate electricity for the term of a new license, making electrical power from a 

renewable resource available to its customers. 

This draft environmental impact statement (draft EIS) assesses the effects 

associated with continued operation of the project and alternatives to the proposed 

project. It also includes recommendations to the Commission on whether to issue a new 

license, and if so, includes the recommended terms and conditions to become a part of 

any license issued. 

In the draft EIS, we assess the environmental and economic effects of continuing 

to operate the project: (1) as proposed by Idaho Power and (2) with our recommended 

measures. We also consider the effects of the no-action alternative. 

Important issues we address include the effects of project operation and 

maintenance on water quality and white sturgeon, as well as the effects of project 

operation, project maintenance, and recreational use of the area within and near the 

project boundary on terrestrial and cultural resources. 

1.2.2 Need for Power 

The Swan Falls Project would provide hydroelectric generation to meet part of the 

state of Idaho’s power requirements, as well as its resource diversity and capacity needs. 

The project would have an installed capacity of 25 MW and generate approximately 

161,300 MWh per year. 

The North American Electric Reliability Corporation (NERC) annually forecasts 

electrical supply and demand nationally and regionally for a 10-year period. The Swan 

Falls Project is located in the Northwest Power Pool area of the Western Electricity 

Coordinating Council region of the NERC. According to NERC’s most recent (2008) 

forecast, winter peak demands and annual energy requirements for the U.S. portion of the 

Northwest Power Pool region are projected to grow at annual rates of 1.65 percent and 

2.68 percent, respectively, from 2008 through 2017 (NERC, 2008). NERC projects 

winter resource capacity margins (generating capacity in excess of demand) will drop 

from 34.7 percent in 2008/2009 to 23.7 percent of firm peak demand by winter 

2012/2013. 

We conclude that power from the Swan Falls Project would help meet a need for 

power in the Northwest Power Pool area in both the short and long term. The project 

provides low-cost power that displaces non-renewable, fossil-fired generation and 

contributes to a diversified generation mix. Displacing the operation of fossil-fueled 

facilities may avoid some power plant emissions, which creates an environmental benefit. 
4 

1.3 STATUTORY AND REGULATORY REQUIREMENTS 

A new license for the Swan Falls Project would be subject to numerous 

requirements under the Federal Power Act (FPA) and other applicable statutes. We 

summarize the major regulatory requirements in table 1 and describe them below. 

Table 1. Major statutory and regulatory requirements for the Swan Falls 

Hydroelectric Project. 

Requirement Agency Status 

Section 18 of the Federal 

Power Act (fishway 

prescriptions) 

Interior Interior filed a reservation of its 

authority to prescribe fishways for 

the project on August 12, 2009. 

Section 10(j) of the 

Federal Power Act 

Idaho DFG Idaho DFG filed section 10(j) 

recommendations on August 14, 

2009. 

Clean Water Act—water 

quality certification 

Idaho DEQ Idaho DEQ issued the final water 

quality certification on May 4, 

2009, and filed the certification on 

August 13, 2009. 

Endangered Species Act 

Consultation 

FWS In a letter filed on September 1, 

2009, FWS indicated that the Snake 

River physa, an endangered species 

of snail, occurs in the project area. 

National Historic 

Preservation Act 

Idaho SHPO Idaho Power consulted with the 

Idaho SHPO, Interior, and the 

Shoshone-Bannock Tribes 

regarding studies to identify 

historic properties and on the draft 

archaeological survey report. 

Comments from these entities were 

received by Idaho Power in letters 

dated December 20, December 21, 

and December 28, 2007, that were 

filed in the application. 

Pacific Northwest Power 

Planning and 

Conservation Act 

FWS, Idaho DFG Idaho Power has consulted with the 

fish and wildlife agencies and 

developed appropriate measures to 

mitigate effects on fish and 

wildlife, as required. 

Notes: Interior – U.S. Department of the Interior 
5 

 FWS – U. S. Department of the Interior, Fish and Wildlife Service 

 Idaho DEQ – Idaho Department of Environmental Quality 

 Idaho DFG – Idaho Department of Fish and Game 

 Idaho SHPO – Idaho State Historic Preservation Officer 

 Shoshone-Bannock Tribes – Shoshone-Bannock Tribes of the Fort Hall 

Reservation 

1.3.1 Federal Power Act 

1.3.1.1 Section 18 Fishway Prescriptions 

Section 18 of the FPA states that the Commission is to require construction, 

operation, and maintenance by a licensee of such fishways as may be prescribed by the 

Secretaries of Commerce or the U.S. Department of the Interior (Interior). Interior, by 

letter filed August 12, 2009, requested that a reservation of authority to prescribe 

fishways under section 18 be included in any license issued for the project. 

1.3.1.2 Section 10(j) Recommendations 

Under section 10(j) of the FPA, each hydroelectric license issued by the 

Commission must include conditions based on recommendations provided by federal and 

state fish and wildlife agencies for the protection, mitigation, or enhancement of fish and 

wildlife resources affected by the project. The Commission is required to include these 

conditions unless it determines that they are inconsistent with the purposes and 

requirements of the FPA or other applicable law. Before rejecting or modifying an 

agency recommendation, the Commission is required to attempt to resolve any such 

inconsistency with the agency, giving due weight to the recommendations, expertise, and 

statutory responsibilities of such agency. 

Idaho Department of Fish and Game (Idaho DFG) timely filed, on August 14, 

2009, recommendations under section 10(j), as summarized by table 18 in section 5.4, 

Fish and Wildlife Agency Recommendations. In section 5.4, we discuss how we address 

the agency recommendations. 

1.3.2 Clean Water Act 

Under section 401 of the Clean Water Act, a license applicant must obtain 

certification from the appropriate state pollution control agency verifying compliance 

with the Clean Water Act. On June 6, 2008, Idaho Power applied to Idaho DEQ for 401 

water quality certification (WQC) for the Swan Falls Project. Idaho DEQ timely issued 

the section 401 WQC on May 4, 2009 (letter from B.N. Burnell, Water Quality Division 

Administrator, Idaho DEQ, dated May 4, 2009). A copy of the certification was filed 

with the Commission on August 13, 2009, and appears in appendix A. The conditions of 
6 

the certification are also described under section 2.2.4, Modifications to Applicant’s 

Proposal—Mandatory Conditions. 

1.3.3 Endangered Species Act 

Section 7 of the Endangered Species Act requires federal agencies to ensure that 

their actions are not likely to jeopardize the continued existence of endangered or 

threatened species or result in the destruction or adverse modification of the critical 

habitat of such species. In a letter filed on September 1, 2009, the U.S. Department of the 

Interior, Fish and Wildlife Service (FWS) indicated that the Snake River physa (Haitia 

[Physa] natricina), an endangered species of aquatic snail, occurs in the project area. 

FWS stated that no threatened, endangered, proposed, or candidate terrestrial plants or 

wildlife species are likely to occur in the Swan Falls Project area, and none were 

identified during special status plant surveys or a review of the literature regarding plants 

and wildlife in the project area. 

In its August 12, 2009, filing providing recommended terms and conditions, 

Interior recommends that Idaho Power consult with FWS to design a suitable sampling 

program to determine the current status and distribution of the Snake River physa near 

the Swan Falls Project and to assess potential project-related effects on the species. In its 

reply comments, Idaho Power stated that it has begun preliminary discussions with FWS 

to develop a sample plan to address concerns related to Snake River physa. Idaho Power 

states that the study plan will address study methods, sample locations and the number of 

samples anticipated to complete the project. Idaho Power anticipates completion of the 

study plan by December 31, 2009, and completion of the study report by June 2010. 

Both the plan and the report would be filed with the Commission upon completion. 

Our analyses of project effects on threatened and endangered species are presented 

in section 3.3.4, Threatened and Endangered Species, and our recommendations in 

section 5.2, Comprehensive Development and Recommended Alternative. We conclude 

that relicensing the Swan Falls Project, as proposed with staff-recommended measures, is 

not likely to adversely affect the Snake River physa because the species is unlikely to be 

located in areas affected by water-level fluctuations related to project operations and 

because continued removal of aquatic vegetation that accumulates on the project’s trash 

racks would improve water quality. We will request FWS concurrence with our 

conclusion at or about the time this draft EIS is issued. 

1.3.4 National Historic Preservation Act 

Section 106 of the National Historic Preservation Act of 1966 (NHPA) requires 

that every federal agency “take into account” how each of its undertakings could affect 

historic properties. Historic properties are districts, sites, buildings, structures, traditional 

cultural properties (TCPs), and objects significant in American history, architecture, 

engineering, and culture that are eligible for inclusion in the National Register of Historic 

Places (National Register). 
7 

Idaho Power consulted with the Idaho State Historic Preservation Officer (Idaho 

SHPO), Interior, and the Shoshone-Bannock Tribes of the Fort Hall Reservation 

(Shoshone-Bannock Tribes) during study development and provided these entities with 

draft versions of the archaeological survey report and Historic Properties Management 

Plan (HPMP) for their review.10 Idaho SHPO, Interior, and the Shoshone-Bannock 

Tribes commented on the documents in letters dated December 28, 20, and 21, 2007, 

respectively. For comments and recommendations with which it agreed, Idaho Power 

revised the survey report and HPMP in June 2008. Idaho Power did not agree to two of 

the Idaho SHPO’s requests: (1) analyze and discuss the physiography of the project area 

to identify fishing-related natural features, and (2) complete a final report for prior 

archaeological work undertaken at site 10AA17. Commission staff also commented on 

the HPMP in October 2008 (see our letter filed October 7, 2008) and Idaho Power revised 

the HPMP and filed it with the Commission in December 2008. Additional comments 

were received from the Shoshone-Bannock Tribes in letters filed August 26, 2008 and 

March 13, 2009. As discussed in section 5.0, the December 2008 HPMP does not 

adequately address all project-related effects. 

To meet the requirements of section 106, the Commission staff intends to execute 

a programmatic agreement (PA) for the protection of historic properties from the effects 

of the Swan Falls Project. The terms of the PA would ensure that Idaho Power addresses 

and treats all historic properties identified within the project’s area of potential effects 

(APE) through the implementation of a final revised HPMP. 

1.3.5 Pacific Northwest Power Planning and Conservation Act 

Under section 4(h) of the Pacific Northwest Power Planning and Conservation 

Act, the Northwest Power and Conservation Council developed the Columbia River 

Basin Fish and Wildlife Program (Program) to protect, mitigate, and enhance the fish and 

wildlife resources associated with development and operation of the hydroelectric 

projects within the Columbia River Basin. Section 4(h) states that responsible federal 

and state agencies should provide equitable treatment for fish and wildlife resources, in 

addition to other purposes for which hydropower is developed, and that these agencies 

should take into account, to the fullest extent practicable, the Program adopted under the 

Pacific Northwest Power Planning and Conservation Act. 

The Program directs agencies to consult with federal and state fish and wildlife 

agencies, appropriate Indian tribes, and the Northwest Power and Conservation Council 

during the study, design, construction, and operation of any hydroelectric development in 

the basin. At the time the application was filed, our regulations required the applicant to 

consult with the appropriate federal and state fish and wildlife agencies and tribes before 

 

10 On February 7, 2008, Idaho Power attempted to contact the Shoshone-Paiute 

Tribes, the Burns-Paiute Tribe, and the Fort McDermitt Paiute and Shoshone Tribe, but 

no responses were received from these tribes. 
8 

filing, and after filing, to provide these groups with opportunities to review and comment 

on the application. Idaho Power has followed this consultation process, and the relevant 

federal and state fish and wildlife agencies and tribes have reviewed and commented on 

the application. 

Although the Swan Falls Project is not located within a protected area designated 

by this Program, the Program directs that hydroelectric projects include measures to 

mitigate their effects on fish and wildlife resources (Program sections 12.1A.1 through 

12.1A.2). The measures described in the proposed action contribute to this goal; 

therefore, the project is consistent with the objectives of this Program. 

1.4 PUBLIC REVIEW AND CONSULTATION 

The Commission’s regulations (18 code of federal regulation [CFR], section [§] 

16.8) require that applicants consult with appropriate resource agencies, tribes, and other 

entities before filing an application for a license. This consultation is the first step in 

complying with the Fish and Wildlife Coordination Act, Endangered Species Act, NHPA, 

and other federal statutes. Pre-filing consultation must be complete and documented 

according to the Commission’s regulations. 

1.4.1 Scoping 

Before preparing this EIS, we conducted scoping to determine what issues and 

alternatives should be addressed. A scoping document (SD1) was distributed to 

interested agencies and others on January 9, 2009. It was noticed in the Federal Register 

on January 15, 2009. In SD1, we requested clarification of preliminary issues concerning 

the Swan Falls Project and identification of any new issues that need to be addressed in 

the EIS. Two scoping meetings, both advertised in the Idaho Statesman, were held on 

February 10 and 11, 2009, in Boise, Idaho, to request oral comments on the project. We 

also had a site visit of the project area on February 10, 2009. A court reporter recorded 

all comments and statements made at the scoping meetings, and these are part of the 

Commission’s public record for the project. In addition to comments provided at the 

scoping meetings, the following entities provided written comments on SD1: 

Commenting Entity Date Filed

Patty Terry February 25, 2009 

Idaho DFG March 11, 2009 

Idaho Department of Parks and 

Recreation (Idaho DPR) 

March 12, 2009 

Shoshone-Bannock Tribes March 13, 2009 

A revised scoping document addressing these comments was issued on May 5, 

2009. 
9 

1.4.2 Interventions 

On December 5, 2008, the Commission issued a notice that Idaho Power had filed 

an application to relicense the Swan Falls Project. This notice set February 3, 2009, as 

the deadline for filing protests and motions to intervene. In response to the notice, the 

following entities filed motions to intervene: 

Intervenor Date Filed

State of Idaho December 17, 2008 

Shoshone-Bannock Tribes January 30, 2009 

1.4.3 Comments on the License Application 

A notice soliciting comments, recommendations, terms and conditions, and 

prescriptions was issued on June 16, 2009. The following entities responded: 

Commenting Agency and Other Entity Date Filed

Interior August 12, 2009 

State of Idaho August 14, 2009 

The applicant filed reply comments on September 29, 2009. 
10 

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11 

2.0 PROPOSED ACTION AND ALTERNATIVES 

2.1 NO-ACTION ALTERNATIVE 

Under the no-action alternative, the Swan Falls Project would continue to operate 

under the terms and conditions of the existing license, and no new environmental 

protection, mitigation, or enhancement measures would be implemented. We use this 

alternative to establish baseline environmental conditions for comparison with 

other alternatives. 

2.1.1 Existing Project Facilities 

The existing Swan Falls Project consists of: (1) a 1,218-foot-long concrete gravity 

and rock-fill dam composed of an abutment embankment, a spillway section, a center 

island, the old powerhouse section, the intermediate dam, and the new powerhouse; (2) a 

12-mile-long, 1,525-acre reservoir with a normal maximum water surface elevation of 

2,314 feet mean sea level (msl); (3) 12 equal-width, concrete spillway sections with 

radial gates, having a total capacity of 105,112 cubic feet per second (cfs) at reservoir 

elevation 2,318 feet msl, divided into two sections (western and eastern)—the western 

section, contiguous with the abutment embankment, is a gated, concrete ogee section 

with eight radial gates, and the eastern section, which is adjacent to the island, contains 

four radial gates; (4) two concrete flow channels; (5) two pit-type, horizontal Kaplan 

turbine generators with a nameplate ratings of 12.5 MW each; (6) a 1,400-foot-long, 120-

foot-wide excavated tailrace channel; (7) a 33,600-kilovolt-ampere main power 

transformer; (8) a 1.2-mile-long, 138-kilovolt transmission line; and 

(9) appurtenant equipment. 

2.1.2 Project Boundary 

Under the existing license, the project boundary includes about 2,192 acres, of 

which 1,255 acres are land and 937 acres are water. The project boundary extends from 

about 12 miles upstream of the dam to about 2,000 feet downstream of the dam. The 

project boundary follows linear boundaries that encompass all major project features, 

including the main project access road, an equipment yard, the dam, a new powerhouse, a 

barn-like storage structure, an orchard, five Idaho Power-owned project houses, a 

transmission line, a yard where trash rack debris is dumped, and five existing project 

recreation sites, including the old powerhouse (which is now a museum). 

2.1.3 Project Safety 

The project has been operating for more than 27 years under the existing license 

and during this time, Commission staff has conducted operational inspections focusing on 

the continued safety of the structures, identification of unauthorized modifications, 

efficiency and safety of operations, compliance with the terms of the license, and proper 

maintenance. In addition, the project has been inspected and evaluated every 5 years by 

an independent consultant and a consultant’s safety report has been submitted for 
12 

Commission review. As part of the relicensing process, the Commission staff would 

evaluate the continued adequacy of the project facilities under a new license. Special 

articles would be included in any license issued, as appropriate. Commission staff would 

continue to inspect the project during the new license term to assure continued adherence 

to Commission-approved plans and specifications, special license articles relating to 

construction (if any), operation and maintenance, and accepted engineering practices 

and procedures. 

2.1.4 Existing Project Operation 

The Swan Falls Project is a reregulating reservoir, with limited storage capacity 

available to provide minimal peaking operations. However, the Swan Falls reservoir is 

not used to store water on a seasonal basis. The 3 feet of limited available storage 

between elevation 2,311 feet msl and 2,314 feet msl is used on a daily basis to re-regulate 

flows from the upstream C.J. Strike Project (FERC Project No. 2055). With its limited 

storage, the Swan Falls Project can be used to meet short-term, unexpected peak load 

requirements. However, the Swan Falls Project is required to comply with ramping rate 

restrictions of no more than 1 foot per hour and 3 feet per day as measured at the ramping 

monitoring gage located approximately 1 mile downstream of the dam. 

The current Swan Falls license, issued in 1982, requires instantaneous minimum 

flows downstream of the Swan Falls dam of no less than 5,000 cfs during the irrigation 

season (April 1 to September 30) and no less than 4,000 cfs outside of the irrigation 

season (October 1 to March 31). If the average daily inflow is less than the specified 

minimums, the project discharge from the powerhouse and/or spillway must be equal to 

the average inflow. 

Under the Swans Falls Agreement, a contract between Idaho Power and the state 

of Idaho entered into on October 25, 1984, Idaho Power’s water rights for power 

purposes at the Swan Falls Project and other specified Idaho Power-owned hydroelectric 

projects on the middle Snake River entitle Idaho Power to an unsubordinated right of 

3,900 cfs average daily flow from April 1 to October 30, and 5,600 cfs average daily flow 

from November 1 to March 31, as measured at the Murphy U.S. Geological Survey 

(USGS) gage (USGS Gage No. 13172500) located downstream of the Swan Falls Project 

near Murphy, Idaho, at river mile (RM) 453.5. During low-flow periods, Idaho Power 

monitors daily average project discharges over a 3-day period to ensure that the average 

minimum flow is at least 3,900 cfs from April 1 to October 31 and at least 5,600 cfs from 

November 1 to March 31 for the purpose of satisfying Idaho Power’s water rights under 

the Swan Falls Agreement. 

2.1.5 Existing Environmental Measures 

The environmental measures that the applicant currently implements are listed 

below. License article numbers are provided in parenthesis where applicable; voluntary 

measures are also noted. 
13 

Aquatic Resources 

• The project is operated to comply with the ramping rate restrictions of no more 

than 1 foot per hour and 3 feet per day and instantaneous minimum flows 

downstream of the Swan Falls dam of no less than 5,000 cfs during the 

irrigation season (April 1 to September 30) and no less than 4,000 cfs outside 

of the irrigation season (October 1 to March 31). (Article 39)11

• The project includes trash racks over the turbine intake, and Idaho Power 

currently removes aquatic macrophytes and debris that accumulate on the 

racks, resulting in decreases in nutrients and oxygen-demanding material from 

the river. (voluntary) 

Recreational Resources 

• The project includes the following five existing project recreation sites located 

within the project boundary: Swan Falls Park, Swan Falls reservoir boat ramp, 

Swan Falls downstream boat launch, the canoe portage trail, and Swan Falls 

powerhouse museum. (Article 406)12

• To minimize risk to the public, the applicant also adheres to measures 

described in its Public Safety Plan, dated June 2008. (voluntary) 

Land Use and Aesthetic Resources 

• Idaho Power has a program for administering its current policy regarding the 

permitting of piers, docks, and other shoreline facilities associated with project 

lands and waters. (Article 51)11

2.2 APPLICANT’S PROPOSAL 

2.2.1 Proposed Project Facilities and Boundary Modifications 

Idaho Power does not propose any changes to generation facilities or other major 

project features. Idaho Power proposes to enhance some existing developed recreational 

areas and harden and formalize some existing informal recreational sites located both 

within and outside of the current project boundary. Idaho Power proposes to amend the 

project boundary to remove 791 acres and to add 192 acres to reflect: (1) acres no longer 

needed for the operation and maintenance of the Swan Falls Project, and (2) areas and 

facilities needed for project purposes such as recreation. With these modifications, the 

new project boundary would encompass approximately 1,593 acres of land and water. 

Upstream of the dam, the proposed project boundary would follow contour 2,318 

feet msl along both sides of the river, extending farther around project features located on 

 

11 Order Issuing New License (Major), December 22, 1982, 21 FERC ¶62,519. 

12 Order Amending License (Major), December 8, 1989, 49 FERC ¶62,227. 
14 

the northeastern side of the river. The proposed project boundary excludes lands located 

upslope from the 2,318-foot-msl contour line that are not needed for project purposes. 

Downstream of the dam, the project boundary would generally include all lands on the 

northeast side of the river between the ordinary high water mark (OHWM)13 and the 

elevation 2,360-foot-msl contour line from the dam downstream to the extent of Idaho 

Power’s proposed recreational enhancements (see figure 4 for the proposed project 

boundary downstream of the dam).14 Table 12 lists Idaho Power’s proposed project 

boundary modifications.15 

2.2.2 Proposed Project Operation 

The applicant proposes a change to the minimum flow regime and continuation of 

the existing ramping rate restrictions. The project would provide instantaneous minimum 

flows of 3,900 cfs from April 1 to October 31, and 5,600 cfs from November 1 to March 

31 each year. The ramping rate restrictions would continue to be no more than 1 foot per 

hour and 3 feet per day. 

2.2.3 Proposed Environmental Measures 

Idaho Power proposes the following mitigation, protection, and enhancement 

measures. 

Aquatic Resources 

• Provide an instantaneous minimum flow of 3,900 cfs downstream of the dam 

from April 1 to October 31, and 5,600 cfs from November 1 to March 31. 

• Continue the ramping rate restrictions of no more than 1 foot per hour and 3 

feet per day. 

• Continue to remove and dispose of aquatic macrophytes and debris that 

accumulate on the project trash racks to remove nutrients and oxygendemanding material from the river. 

 

13 Ordinary high water mark refers to the line that water impresses on the soil by 

covering it for sufficient periods. 

14 Idaho Power plans to obtain submerged land easement rights (lands below the 

OHWM) from the Idaho Department of Lands, as well as any other state and federal 

permits necessary to ensure public access below the OHWM at proposed recreation sites 

located downstream of the dam. 

15 Idaho Power’s exhibit G drawings would need to be modified and re-filed with 

the Commission if the proposed project boundary modifications would be approved by 

the Commission. The current exhibit G drawings filed with the license application do not 

reflect the proposed project boundary. 
15 

• Monitor water temperature and dissolved oxygen (DO) in the project outflow. 

• Implement resident fish monitoring in Swan Falls reservoir and in the first 15 

miles of the river downstream of Swan Falls dam to determine long-term 

trends in fish populations. 

Terrestrial Resources 

• Implement the Wildlife Habitat and Enhancement Plan to protect, enhance, and 

restore upland and riparian habitat on applicant-owned lands within the project 

boundary, including closing nine dispersed recreation sites.16 

• Implement the Noxious Weed Management Plan to control noxious and 

undesirable weed species on applicant-owned lands and cooperatively manage 

noxious and undesirable species on other lands within the project boundary. 

• Implement the Special Status Plant Management Plan to protect and monitor 

special status plant species on applicant-owned and other lands within the 

project boundary. 

• Develop and implement a transmission line operation and maintenance plan. 

Recreation Resources 

• Finalize and implement the draft Recreation Management Plan, which includes 

the following elements: 

 Continue operation and maintenance of five existing project recreation 

sites: Swan Falls Park, Swan Falls reservoir boat ramp, Swan Falls 

downstream boat launch, the canoe portage trail, and Swan Falls 

powerhouse museum.17

 Enhance the Swan Falls reservoir boat ramp by upgrading the boat ramp, 

adding a vault toilet, and enhancing parking for vehicles and trailers. 

 Improve Swan Falls Park by providing riprap or a retaining wall along 

the shoreline, and adding a new dock, picnic tables, and a shelter. 

 

16 Restoring upland and riparian habitat refers to closing braided roads and nine 

dispersed recreation sites that are located within the project boundary and revegetating 

those lands as part of the Wildlife Habitat and Enhancement Plan. 

17 Idaho Power’s proposed HPMP includes a provision to improve Swan Falls 

powerhouse museum’s interpretive and education displays and increase days and hours of 

availability to include every Saturday between April 15 and Labor Day, from 10:00 a.m. 

to 4:00 p.m. 
16 

 Enhance the Swan Falls downstream boat launch by constructing a twolane boat ramp, adding a vault toilet, enhancing parking for vehicles and 

trailers, and removing the air compressor. 

 Improve the canoe portage trail by installing signage. 

 Enhance six existing dispersed recreation sites located either within or 

near the current project boundary (the sites outside the current project 

boundary are proposed to be included within the new project boundary) 

that provide access to the reservoir and river. 

 Implement the Litter and Sanitation Plan, including additional vault 

toilets and dumpsters, as well as biannual litter pickups and a carryin/carry-out policy within the project boundary and outside of the project 

boundary (downstream to RM 453.4). 

 Finalize and implement the Interpretation and Education Plan. 

• Continue implementation of the applicant’s Public Safety Plan, dated 

June 2008. 

Land Use and Aesthetic Resources 

• Implement the Visual Guidelines Plan, which includes the following elements: 

 Modify the colors of the five Idaho Power-owned project houses to blend 

with soils and vegetation. 

 Paint the wooden elements associated with BLM’s key observation point 

(KOP) 2, which is a parking and restroom area near the powerhouse. 

 Establish screening around the lay-down yard. 

 Ensure that any new construction considers the protection of visual 

resources from important viewpoints. 

• Develop and implement a consistent signage plan for the entire project area 

and adjoining applicant-owned lands. 

• Finalize and implement the Resource Management Plan to guide Idaho Power 

staff in its hydroelectric operations and maintenance of the Swan Falls Project, 

including project-related measures to protect cultural and natural resources. 

• Continue implementation of policies for permitting piers, boat docks, and other 

facilities (non-project use of project lands and waters). 

Cultural Resources 

• Implement the project’s December 2008 HPMP. 
17 

2.2.4 Modifications to Applicant’s Proposal—Mandatory Conditions 

The following mandatory conditions have been provided and are evaluated as part 

of the applicant’s proposal. 

Section 18 Prescriptions 

Interior, by letter filed August 12, 2009, reserved its authority to prescribe 

fishways under section 18 of the FPA for the Swan Falls Project. 

Section 4(e) Land Management Conditions 

No agency submitted mandatory conditions pursuant to FPA section 4(e). 

Water Quality Certification Conditions 

The conditions of the WQC (appendix A) specify the following: 

Idaho Power will develop, in consultation with Idaho DEQ, a water quality 

monitoring plan and submit the plan to Idaho DEQ for approval within 6 months after 

issuance of a new license. The plan, which will include a quality assurance control 

project plan, will describe the location and method of monitoring for discharge flows, 

DO, total dissolved gas (TDG), and water temperature in the reservoir and downstream 

from the project. 

Idaho Power will submit annual reports to Idaho DEQ, summarizing the results of 

its water quality monitoring as described in the water quality monitoring plan. After 5 

years, Idaho Power may request the termination of all or some of its monitoring described 

in the plan, except for the elements proposed in its license application (i.e., monitor water 

temperature and DO in the project outflow). 

2.3 STAFF ALTERNATIVE 

The staff alternative would include Idaho Power’s proposed measures, with the 

exception of implementing the proposed resident fish monitoring program, and 

developing and implementing a transmission line operation and maintenance plan. The 

staff alternative would modify and/or add the following measures: 

Aquatic Resources 

• Develop and implement a plan with provisions to monitor water temperature 

and DO in the project’s outflow seasonally each license year as proposed by 

Idaho Power and monitor water temperature and DO in the project’s inflow 

and discharge and TDG in the project’s inflow and outflow for at least 5 years 

after license issuance as stipulated in Idaho DEQ’s WQC; develop a quality 

assurance control plan; submit annual data reports to Idaho DEQ and the 

Commission; and prepare and file a report with the Commission with a copy to 

Idaho DEQ summarizing the results of the first 5 years of monitoring, and 

describing any proposed changes to the monitoring program. 
18 

Terrestrial Resources 

• Implement timing restrictions on transmission line maintenance activities, as 

needed, to protect benchland nesters and cliff-nesting raptors. 

Recreation Resources 

• Revise and implement the Recreation Management Plan to include: (1) 

completion of Idaho Power’s consultation with Idaho SHPO to ensure that 

work planned at the informal dispersed sites and associated access roads 

consider the effects on cultural resources known to exist in the area; (2) soil 

erosion control measures; (3) detailed design drawings of Swan Falls Park, 

Swan Falls reservoir boat ramp, Swan Falls downstream boat launch, and the 

canoe portage trail; (4) a description of improvements to the six dispersed 

recreation sites; (5) a discussion on how the needs of the disabled were 

considered in the planning and design of the recreation facilities; (6) an 

implementation schedule; (7) modification of the Litter and Sanitation Plan so 

that it applies only to lands within the project boundary; and (8) finalization 

and implementation of the Interpretation and Education Plan as part of the 

Recreation Management Plan in consultation with BLM, Idaho DPR, and 

Idaho SHPO. 

• Establish an interagency recreation working group that convenes every 6 years 

in coordination with preparing the FERC Form 8018 to assess recreation 

facilities, dispersed recreation sites, and usage. 

Land Use and Aesthetic Resources 

• Revise the proposed Visual Guidelines Plan to include a list of neutral paint 

color schemes, a list of vegetation species for vegetation, a list of construction 

materials that could be used, and documentation of consultation with BLM and 

Idaho DPR. 

Cultural Resources 

• Revise the December 2008 HPMP to include a program for immediate 

mitigation measures for sites being affected by shoreline erosion, vandalism, 

and recreation improvements. The program will include a consultation process 

between Idaho Power, Idaho SHPO, BLM, and participating tribes to formulate 

site-specific mitigation measures. The anticipated PA would implement the 

final revised HPMP. 

 

18 Licensed Hydropower Development Recreation Report—Form 80. 
19 

2.4 ALTERNATIVES CONSIDERED BUT ELIMINATED FROM FURTHER 

ANALYSIS 

We considered several alternatives to the applicant’s proposal, but eliminated 

them from further analysis because they are not reasonable in the circumstances of this 

case. They are: (1) issuing a non-power license, (2) federal government takeover of the 

project, and (3) retiring the project. 

2.4.1 Issuing a Non-power License 

A non-power license is a temporary license that the Commission will terminate 

when it determines that another governmental agency will assume regulatory authority 

and supervision over the lands and facilities covered by the non-power license. At this 

point, no agency has suggested a willingness or ability to do so. No party has sought a 

non-power license and we have no basis for concluding that the project should no longer 

be used to produce power. Thus, we do not consider issuing a non-power license a 

realistic alternative to relicensing in this circumstance. 

2.4.2 Federal Government Takeover of the Project 

We do not consider federal takeover to be a reasonable alternative. Federal 

takeover and operation of the project would require Congressional approval. While that 

fact alone would not preclude further consideration of this alternative, there is no 

evidence to indicate that federal takeover should be recommended to Congress. No party 

has suggested federal takeover would be appropriate, and no federal agency has 

expressed an interest in operating the project. 

2.4.3 Retiring the Project 

Project retirement could be accomplished with or without dam removal. Either 

alterative would involve denial of the relicense application and surrender or termination 

of the existing license with appropriate conditions. Existing recreation facilities would be 

operated and maintained by other entities or removed. Project retirement with dam 

removal would have the following effects: 

• The energy generated by the project, estimated to be about 161,300 MWh per 

year, would be lost. If the energy were no longer available, it would have to be 

replaced by an alternative source of energy with its associated environmental 

effects (including emissions of air pollutants). 

• Project-generated employment and project-generated tax revenues would 

be lost. 

• The environmental enhancements proposed by Idaho Power (see section 3.1.3), 

including habitat improvements and recreational enhancements, the protection 

of historic properties, and any additional enhancement measures required by 

the Commission, would be foregone. 
20 

• Short-term increases in downstream turbidity and sedimentation and temporary 

increases in noise, dust, exhaust emissions, and traffic in the project vicinity 

during dam removal activities would result. 

• Loss of more than 1,525 acres of flatwater would result and the existing 

recreational benefits attributed to the project's reservoir (swimming, boating, 

fishing) would be lost or substantially reduced. 

• Use of existing recreational facilities (picnic areas, restrooms, boat ramps, etc.) 

operated and maintained by Idaho Power would be lost if not taken over and 

managed by other entities. 

• Removal of the dam would increase riverine habitat benefiting fish, wildlife, 

and riparian resources. In addition, recreational opportunities associated with 

riverine-type conditions would increase. 

• Cessation of operation would eliminate impacts associated with water-level 

fluctuations in the reservoir and in downstream reaches, which could benefit 

fish and riparian habitats. 

• Visual benefits could result from removal of project structures and 

transmission lines, thereby changing the landscape. 

• Fish passage and survival would improve. 

The second project retirement alternative would involve retaining the dam and 

disabling or removing equipment used to generate power. Project works would remain in 

place and could be used for historic or other purposes. This would require the 

Commission to identify another government agency with authority to assume regulatory 

control and supervision of the remaining facilities. No agency has stepped forward to 

assume that control, and no participant has advocated this alternative. Nor have we any 

basis for recommending it. Because the power supplied by the project is needed, a source 

of replacement power would have to be identified. 

Although the Shoshone-Bannock Tribes commented that project decommissioning 

should be evaluated in the EIS, we conclude that project decommissioning, either with or 

without dam removal, is not a reasonable alternative in this case. 
21 

3.0 ENVIRONMENTAL ANALYSIS 

In this section, we present: (1) a general description of the project vicinity, 

(2) an explanation of the scope of our cumulative effects analysis, and (3) our 

analysis of the proposed action and other recommended environmental measures. 

Sections are organized by resource area. Under each resource area, historic and 

current conditions are first described.19 The existing condition is the baseline 

against which the environmental effects of the proposed action and alternatives are 

compared, including an assessment of the effects of proposed mitigation, 

protection, and enhancement measures, and any potential cumulative effects of the 

proposed action and alternatives. Staff conclusions and recommended measures 

are discussed in section 5.2, Comprehensive Development and 

Recommended Alternative. 

3.1 GENERAL DESCRIPTION OF THE RIVER BASIN 

The Swan Falls Project lies approximately 35 miles southwest of Boise, 

Idaho, on the Snake River in Ada and Owyhee counties. The project is located in 

the southwestern portion of the Snake River Plain. The Snake River Canyon 

bisects the plain and is the principal physiographic feature in the vicinity of the 

project. Cliffs and sheer canyon walls range in height from 6 feet to 375 feet, with 

the river cutting as much as 750 feet below the surrounding terrain (USGS, 1996). 

The elevation of the canyon near Swan Falls dam, where the canyon is deepest, 

ranges from elevation 2,100 feet msl to elevation 2,760 feet msl at the rim (see 

cover photo). North of the river, the terrain is relatively flat or slightly rolling, 

except for isolated buttes. Areas to the south of the river are characterized by 

rolling topography and eroded badlands. 

The project occupies lands of the United States within the Snake River 

Birds of Prey National Conservation Area (NCA), which BLM administers.20 

There are no other developments in the immediate vicinity of the project. The 

closest hydroelectric projects are C.J. Strike, about 36 river miles upstream, and 

the Brownlee development of the Hells Canyon Project (FERC Project No. 1971), 

about 173 river miles downstream. Access to the Swan Falls Project is by county 

road from the town of Kuna, located approximately 19 miles north of the project. 

 

19 Unless otherwise indicated, our information is taken from the application 

for license for this project (Idaho Power, 2008a) and additional information filed 

by Idaho Power (2008b, 2009a, 2009b, and 2009c). 

20 The Snake River Birds of Prey NCA was established on August 4, 1993, 

by Public Law 103-64 for the conservation, protection, and enhancement of the 

environmental resources and values associated with the area, including raptors 

and habitats. 
22 

The Snake River flows generally from southeast to northwest at the Swan 

Falls Project. There are no major tributaries in the vicinity of the project. The 

drainage area at USGS Gage No. 13172500 (Snake River near Murphy, Idaho), 

located on the Snake River a short distance downstream of Swan Falls dam, is 

approximately 41,000 square miles. The existing project was constructed on the 

upstream edge of waterfalls caused by a ridge of basalt extending across the river. 

The average drop across the falls is approximately 15 feet. Swan Falls reservoir is 

a long and narrow water body confined within the canyon through which the 

Snake River flows. 

Hot, dry summers and mild winters characterize the climate of 

southwestern Idaho. The climate is strongly influenced by the orographic 

precipitation shadow of the Oregon Coast Range and the Cascade Mountains to 

the west and the Owyhee Mountains to the south. Average annual precipitation at 

Boise Airport is 11.9 inches, declining toward the west and south (Kuna, 10.2 

inches; Swan Falls powerhouse, 7.9 inches; and Grand View, 7.1 inches), with 

most precipitation occurring between November and May. Mean annual 

temperatures vary between 49.8 degrees Fahrenheit at Kuna to 55.2 degrees 

Fahrenheit at the Swan Falls powerhouse. Droughts are common in southwestern 

Idaho, occurring about every 20 years since 1900 (USGS, 1996). 

3.2 SCOPE OF CUMULATIVE EFFECTS ANALYSIS 

According to the Council on Environmental Quality’s regulations for 

implementing the National Environmental Policy Act of 1969 (40 CFR §1508.7), 

a cumulative effect is the impact on the environment that results from the 

incremental impact of the action when added to other past, present and reasonably 

foreseeable future actions regardless of what agency (federal or non-federal) or 

person undertakes such actions. Cumulative effects can result from individually 

minor but collectively significant actions taking place over time, including 

hydropower and other land and water development activities. 

Based on our review of the license application and agency and public 

comments, we have identified the resources that have the potential to be 

cumulatively affected by operation of the Swan Falls Project in combination with 

other past, present, and foreseeable future activities. Those resources are water 

quality, white sturgeon, and riparian habitat.21 

Water quality was selected because conditions in the Swan Falls reach are 

affected by upstream water uses and by nutrient inputs from municipal and 

agricultural sources throughout the basin upstream of the project. White sturgeon 

 

21 Riparian habitat, as classified in Idaho Power’s vegetation cover type 

mapping effort (Krichbaum et al., 2008), includes emergent, scrub-shrub, forested, 

and shore and bottomland wetlands. 
23 

were selected because numerous mainstem dams on the Snake River, including 

Swan Falls dam, restrict migration of this species and the connectivity of sturgeon 

populations between reaches, and because sturgeon rearing and reproduction in the 

Swan Falls reach are affected by cumulative effects on water quality. We selected 

riparian habitat because it may be affected by water withdrawals for irrigation and 

by load-following operations associated with other Snake River dams, as well as 

by operation of the Swan Falls Project. 

3.2.1 Geographic Scope 

The geographic scope of the analysis for cumulatively affected resources is 

defined by the physical limits or boundaries of: (1) the proposed action’s effects 

on the resources, and (2) contributing effects from other hydropower and nonhydropower activities within the Snake River Basin. Because the proposed action 

can affect the resources differently, the geographic scope for each resource 

may vary. 

For water quality, we define the geographic scope as the entire Snake River 

Basin upstream from Brownlee dam (RM 284.6). For white sturgeon and riparian 

habitat, we define the geographic scope of the analysis as the Snake River main 

stem between Brownlee dam and C.J. Strike dam (RM 494.0). 

3.2.2 Temporal Scope 

The temporal scope of our cumulative effects analysis in the EIS includes 

past, present, and future actions and their possible cumulative effects on each 

resource. Based on the potential term of a new license, the temporal scope looks 

30 to 50 years into the future, concentrating on the effect on the resources from 

reasonably foreseeable future actions. The historical discussion, by necessity, is 

limited to the amount of available information for each resource. The quality and 

quantity of information, however, diminishes as we analyze resources further 

away in time from the present. 

3.3 PROPOSED ACTION AND ACTION ALTERNATIVES 

In this section, we discuss the effect of the project alternatives on 

environmental resources. For each resource, we first describe the affected 

environment, which is the existing condition and baseline against which we 

measure effects. We then discuss and analyze the site-specific and cumulative 

environmental issues. 

Only the resources that would be affected, or about which comments have 

been received, are addressed in detail in this EIS. We present our 

recommendations in section 5.2, Comprehensive Development and 

Recommended Alternative. 
24 

3.3.1 Geology and Soil Resources 

3.3.1.1 Affected Environment 

The geology of the western portion of the Snake River Plain is 

characterized by thick accumulations of geologically recent basalt flows 

interbedded with sedimentary strata of lake and stream origins. 

During approximately the last 10,000 years, erosion has created talus and 

alluvium along streams and resulted in the accumulation of thin deposits of 

windblown sand and silt on some flatter areas. Floodplains are currently being 

formed along the Snake River and a few of the larger tributary streams. 

The benchlands north of the Snake River are on a broad basalt plain with 

several isolated cinder cones and basaltic buttes. The soils are generally lightcolored, fine-textured to stony soils that have developed on basalt, sedimentary 

strata, and wind-modified deposits (loess). The soils along the river and 

floodplain of the Snake River vary from deep loams in the Chattin Flat area to thin 

gravelly and cobbly soils on gravel bars and low terraces. Soils that have been 

mapped along the Snake River channel and alluvial plain include the Bram, 

Baldock, Vanderhoff, and Feltham series. 

Soils in the transition zone between the bottom soils and the upland soils 

are variable, ranging from deep silty and sandy loams on high terraces and 

colluvium to terrace escarpments and rubble land. 

Bank erosion occurs on project lands upstream and downstream of the dam 

and on non-project lands. Upstream of the dam, bank erosion is related to highly 

erodible soils, cattle grazing, irrigation seepage, and impoundment fluctuations 

and flow variations resulting from the operation of the C.J. Strike and Swan Falls 

projects. Bank erosion is also associated with informal recreational areas, 

primarily in the vicinity of the existing boat ramp upstream of the dam and at 

various locations within the first 2 miles downstream of the dam. 

Visitor use of dispersed recreation sites, including off-road vehicle use 

within and outside of the current project boundary, has created a series of braided 

roads or multiple access roads and has eliminated vegetation and caused the 

formation of severe ruts. Such upland erosion and de-vegetation has occurred in 

many areas along the main access roads upstream and downstream of the dam. 

Idaho Power has made some efforts in the past to prevent riparian and upland 

erosion and de-vegetation by establishing the upstream and downstream boat 

launch areas and placing boulders, fences, and gates in the vicinity of the upstream 

boat launch to try to prevent access to natural areas. 
25 

3.3.1.2 Environmental Effects 

Most of the upland erosion associated with the project is from recreational 

use of natural areas beyond the designated project recreation sites. Numerous 

informal dispersed recreation sites have developed over time at various locations 

along the river for access to the river for fishing or other recreational purposes. 

The existing downstream project boundary is located approximately 2,000 

feet downstream of the dam, although a significant amount of additional 

recreational use associated with the project occurs as far as 2 miles downstream of 

the dam. In this area of non-project land downstream of the dam, informal 

recreational access to the river has developed over time, and vehicles driven off 

the main access road downstream of the dam have resulted in a myriad of braided 

loops and trails on either side of the main road. The development of these loops 

and trails has removed existing vegetation, affected surface runoff patterns, destabilized soils resulting in surface erosion, affected botanical resources and 

habitat for wildlife, and caused damage to known cultural resource sites and 

potentially to unknown sites. The effects on botanical, wildlife, recreation, land 

use and cultural resources are discussed in more detail under those resource 

sections later in this document. 

Idaho Power proposes to limit vehicular access by using strategically 

placed boulders, temporary fences, berms, and signage in some areas to protect 

existing resources, along with protecting and enhancing 25.1 acres of riparian 

habitat and 45.3 acres of upland habitat. Idaho Power also proposes to protect, 

enhance, or restore 2.7 miles of riparian shoreline downstream of the dam and to 

restore 8.9 acres of channel riparian habitat along the east side of the Swan Falls 

Island to mitigate the effects of project operation. Additionally, Idaho Power 

proposes to establish more formal, hardened recreational access locations 

upstream and downstream of the dam to prevent future soil erosion and protect 

environmental, recreational, and cultural resources. 

In its comments filed on August 14, 2009, the state of Idaho indicated that 

Idaho DFG, Idaho DPR, Idaho DEQ, the Water Resource Board, and the State 

Board of Land have endorsed Idaho Power’s proposal to restore damaged areas, 

improve informal dispersed recreation sites, and protect existing resources. 

To encompass the informal dispersed recreation sites currently used for 

recreation and proposed to be improved, Idaho Power proposes to include the sites 

as project features and to expand the project boundary for approximately 2 miles 

downstream of the dam. The expanded project boundary would include the land 

area from the OHWM along the east side of the river to the elevation 2,360-foot 

msl contour, with a few exceptions. 

In addition to recreational activity and other land uses, changes in water 

surface fluctuations that result from project operation may contribute to shoreline 
26 

erosion. The effects of such erosion vary from resource to resource; for example, 

studies conducted by Wulforst et al. (2000) and Holmstead and Turley (2005) 

indicate that effects on terrestrial resources are negligible, but erosion surveys 

conducted to evaluate project effects on cultural resources along the shoreline both 

upstream and downstream of Swan Falls dam (Root et al., 2008) found substantial 

impacts on the integrity of 10 sites as a result of water surface fluctuations. These 

effects and Idaho Power’s proposal to address them are discussed in sections 3.3, 

Terrestrial Resources, and 3.7, Cultural Resources, respectively. 

Our Analysis 

The proposed measures would restore, enhance, and protect approximately 

79 acres of land and 2.7 miles of riparian shoreline, formalize recreational access 

and use areas, eliminate informal recreational access and use in areas where Idaho 

Power is attempting to protect project resources, and include all of these lands 

within the proposed modified project boundary. These efforts would reduce 

erosion, thereby benefitting project resources in the area, including botanical, 

wildlife, and recreational resources, as well as land use. These efforts may also 

benefit cultural resources as long as they adhere to the requirements of the HPMP 

and potential adverse effects on cultural resources are considered prior to ground 

disturbance. Specific effects on terrestrial, recreation, and cultural resources are 

discussed in more detail in the resource sections presented later in this document. 

3.3.2 Aquatic Resources 

The following sections describe the affected aquatic environment and the 

environmental effects of the proposed action and action alternatives on water 

quantity, water quality, and fishery resources. 

3.3.2.1 Affected Environment 

Water Quantity 

The Snake River drains approximately 41,900 square miles above Swan 

Falls dam. The mean flow of the Snake River averages 10,970 cfs based on the 

October 1, 1913, through September 30, 2006, period of record for USGS Gage 

No. 13172500 (Snake River near Murphy, Idaho), which is located a short 

distance downstream of Swans Falls dam at RM 453.5. 

Swan Falls reservoir is approximately 12 miles long and has a surface area 

of 1,525 acres at the full-pool elevation of 2,314 feet msl. The gross reservoir 

storage capacity is approximately 7,425 acre-feet, and the useable storage capacity 

is 680 acre-feet when drawn down to elevation 2,310 feet msl. Most 

impoundment fluctuations are within the top 2 feet of the reservoir with infrequent 

fluctuations close to 4 feet. 
27 

Table 2 summarizes the average, maximum, and minimum flows at the 

project for the 93-year period of record from 1913 to 2006. 

Swan Falls reservoir is not used to store water on a seasonal basis. The 3 

feet of available storage between elevation 2,311 feet msl and 2,314 feet msl are 

used on a daily basis to re-regulate flows from the upstream C.J. Strike Project. 

With its limited storage, the Swan Falls Project can be used to meet short-term, 

unexpected peak load requirements. However, the project is required to comply 

with ramping rate restrictions of no more than 1 foot per hour and 3 feet per day as 

measured at the ramping monitoring gage located approximately 1 mile 

downstream of the dam. 

The current Swan Falls license, issued in 1982, requires instantaneous 

minimum flows downstream of the Swan Falls dam of no less than 5,000 cfs 

during the irrigation season (April 1 to September 30) and no less than 4,000 cfs 

outside of the irrigation season (October 1 to March 31). If the average daily 

inflow is less than the specified minimums, the project discharge from the 

powerhouse and/or spillway must be equal to the average inflow. 

Under the Swans Falls Agreement, a contract between Idaho Power and the 

state of Idaho entered into on October 25, 1984, Idaho Power’s water rights for 

power purposes at the Swan Falls Project, and other specified Idaho Power-owned 

hydroelectric projects on the middle Snake River, entitle Idaho Power to an 

unsubordinated right of a 3,900-cfs average daily flow from April 1 to October 31, 

and 5,600-cfs average daily flow from November 1 to March 31, as measured at 

the Murphy USGS gage (USGS Gage No. 13172500). During low-flow periods, 

Idaho Power monitors daily average project discharges over a 3-day period to 

ensure that the average minimum flow is at least 3,900 cfs from April 1 to October 

31 and at least 5,600 cfs from November 1 to March 31 for the purpose of 

satisfying Idaho Power’s water right under the Swan Falls Agreement. 
28 

Table 2. Estimated inflows for the Swan Falls Project (water years 1913–2006) (Source: USGS, 20Flow (cfs) Oct. Nov. Dec. Jan. Feb. Mar. Apr. May Jun. Jul. Average 10,400 11,100 11,300 11,400 11,700 12,100 13,300 12,800 12,700 7,900 Maximum 29,700 23,800 35,000 28,100 33,700 30,600 33,600 37,900 46,100 39,10

Minimum 5,840 6,170 5,440 6,070 5,850 5,690 5,170 4,820 4,310 4,160 
29 

Water Quality 

Water quality within the Snake River has been compromised by the cumulative 

effects of decades of agricultural and industrial activities within the watershed. Upstream 

of Swan Falls dam, most of the reaches between Shoshone Falls (RM 514.7) and Swan 

Falls dam (RM 457.7) are listed as being water quality limited for sediment, temperature, 

DO, or nutrients, and reaches from Swan Falls dam downstream to Brownlee dam (RM 

285) are listed for nutrients, DO, pH, bacteria, mercury, sediment, or flow alteration 

(table 3). 

Table 3. Water quality impaired segments of the Snake River between Shoshone 

Falls and Brownlee dam (Source: Idaho Power Company, 2008a,b). 

River Segment Listed Pollutants Designated Beneficial Uses 

Snake River: RM 614.7 to 

606.4 (Shoshone Falls to 

Rock Creek) 

Sediment, temperature Coldwater biota, salmonid 

spawning, primary contact 

recreation 

Snake River: RM 606.4 to 

599.1 (Rock Creek to 

Cedar Draw Creek) 

Sediment, temperature Coldwater biota, salmonid 

spawning, primary contact 

recreation 

Snake River: RM 599.1 to 

594.2 (Cedar Draw Creek 

to Clear Lakes ridge) 

Sediment, temperature Coldwater biota, salmonid 

spawning, primary contact 

recreation 

Snake River: RM 594.2 to 

591.5 (Clear Lakes Bridge 

to Mud Creek) 

Sediment, temperature Coldwater biota, salmonid 

spawning, primary contact 

recreation 

Snake River: RM 591.5 to 

591.4 (Mud Creek to Deep 

Creek) 

Sediment, temperature Coldwater biota, salmonid 

spawning, primary contact 

recreation 

Snake River: RM 586.1 to 

581.4 (Upper Salmon Falls 

reservoir) 

DO, flow alteration, 

sediment 

Coldwater biota, salmonid 

spawning, primary contact 

recreation 

Snake River: RM 579.6 to 

573.0 (Lower Salmon Falls 

reservoir) 

DO, flow alteration, 

sediment 

Coldwater biota, salmonid 

spawning, primary contact 

recreation 

Snake River: RM 565.0 to 

560.0 (Bliss reservoir) 

Bacteria, DO, flow 

alteration, ammonia, 

sediment 

Coldwater biota, salmonid 

spawning, primary contact 

recreation 
30 

River Segment Listed Pollutants Designated Beneficial Uses 

Snake River: RM 559.9 to 

556.6 (Cassia Gulch to Big 

Pilgrim Gulch) 

Nutrients, sediment, 

temperature 

Coldwater biota, salmonid 

spawning, primary contact 

recreation 

Snake River: RM 556.6 to 

544.9 (Big Pilgrim Gulch 

to King Hill) 

Sediment, temperature Coldwater biota, salmonid 

spawning, primary contact 

recreation 

Snake River: RM 544.9 to 

512.8 (King Hill to C.J. 

Strike reservoir at 

Highway 51 Bridge) 

Sediment Coldwater biota, domestic water 

supply, primary contact 

recreation, special resource 

water 

Snake River: RM 512.8 to 

494.0 (C.J. Strike 

reservoir) 

Nutrients, pesticides Coldwater biota, primary contact 

recreation, special resource 

water 

Snake River: RM 494.0 to 

471.0 (C.J. Strike reservoir 

to Castle Creek) 

Temperature, sediment Coldwater biota, domestic water 

supply, primary contact 

recreation, special resource 

water 

Snake River: RM 471.0 to 

457.7 (Castle Creek to 

Swan Falls) 

Temperature, sediment Coldwater biota, domestic water 

supply, primary contact 

recreation, special resource 

water 

Snake River: RM 457.7 to 

396.4 (Swan Falls to Boise 

River inflow) 

Bacteria, temperature, 

DO, flow alteration, 

nutrients, pH, sediment 

Coldwater biota, domestic water 

supply, primary contact 

recreation, special resource 

water 

Snake River: RM 396.4 to 

351.6 (Boise River inflow 

to Weiser River inflow) 

Bacteria, nutrients, pH, 

sediment 

Coldwater biota, primary contact 

recreation, domestic water 

supply 

Snake River: RM 351.6 to 

347 (Weiser River inflow 

to Scott Creek inflow) 

Bacteria, nutrients, pH, 

sediment 

Coldwater biota, primary contact 

recreation, domestic water 

supply 

Snake River: RM 347 to 

284.6 (Brownlee reservoir, 

Scott Creek to Brownlee 

dam) 

DO, mercury, nutrients, 

pH, sediment 

Coldwater biota, primary contact 

recreation, domestic water 

supply, special resource water 

Note: DO – dissolved oxygen 

RM – river mile 
31 

For the reaches upstream of C.J. Strike dam (RM 514.7 to RM 494), the river’s 

water quality may decline significantly during low-flow periods, which typically occur in 

mid- to late summer. During the summer irrigation season when water is in high 

demand, diversions and irrigation returns reduce stream flows and degrade water quality. 

Because the Snake River is bordered by cultivated fields, groundwater discharges, fish 

farms, and municipal wastewater-treatment facilities, return flows display a combination 

of excessive nitrogen, phosphorus, pesticides, and sediment. 

Conditions from mid- to late summer in these upper reaches also drive reductions 

in downstream water quality. Water quality conditions are further degraded by pollutants 

from Snake River tributaries, many of which deliver substantial nutrient loads to the 

Snake River, especially in the reach between Swan Falls dam and Brownlee reservoir 

(table 4). The location of these tributaries in relationship to Swan Falls dam is shown in 

figure 2. To address the DO listing in the reach downstream from Swan Falls dam (see 

table 3), a nutrient total maximum daily load (TMDL) based on a total phosphorus target 

of 0.07 milligram per liter (mg/L) was established in the Mid-Snake River/Succor Creek 

Subbasin Assessment and Total Maximum Daily Load (Idaho DEQ, 2003). 

Table 4. Estimated phosphorus loadings from tributaries and point sources to the 

Snake River between the C.J. Strike and Brownlee dams (Source: FERC, 

2007). 

Stream or 

Discharge Source 

Drainage Area 

(square miles) Snake River Mile 

Total Phosphorus 

Load 

(kg/day) 

Owyhee River 11,108 396.7 265 

Boise River 4,031 396.4 1,114 

City of Nyssa NA 385 11 

Amalgamated Sugar NA 385 50 

City of Fruitland NA 373 5.5 

Heinz Frozen Foods NA 370 412 

Malheur River 4,719 368.5 461 

Payette River 3,309 365.6 710 

City of Weiser, ID NA 352 32 

City of Weiser, ID NA 352 5.5 

Weiser River 1,686 351.6 392 

Burnt River 1,100 327.5 52 

Powder River 1,705 293 126 
32 

Figure 2. Map of the Swan Falls to Brownlee reach of the Snake River 

(Source: Idaho Power, 2008b). 
33 

Snake River water quality issues are typically exacerbated by low water 

conditions, when water temperatures and residence time in the river and reservoirs 

increase. Increases in primary productivity, phytoplankton levels, nutrient 

concentrations, and drifting clumps and mats of aquatic macrophytes and macroalgae also 

occur commonly in low water years. These increases in primary productivity can lead to 

large DO swings in a 24-hour period. 

The state of Idaho’s coldwater aquatic life DO criterion of a minimum of 6.0 mg/L 

applies at the inflow of the Swan Falls Project year-round, and at the outflow from 

October 16 to June 14. The hydroelectric DO criteria apply at the outflow from June 15 

to October 15, requiring that DO levels be above 3.5 mg/L as an instantaneous minimum; 

4.7 mg/L as a 7-day mean minimum; and 6.0 mg/L as a 30-day mean (Idaho 

Administrative Code 58.01.02). 

Water quality monitoring conducted by Idaho Power upstream and downstream of 

Swan Falls dam from 1989 through 2006 found that DO conditions were highly variable, 

ranging from highly supersaturated to below numeric criteria at both inflow and outflow 

locations. The lowest water year on record (2003) showed the most critical DO 

conditions. In 2003, inflow and outflow DO were below the coldwater criterion during 6 

and 5 percent of the sampled days, respectively. A single, daily minimum outflow value 

of 3.4 mg/L, measured in July 2003, was below the 3.5-mg/L instantaneous hydroelectric 

criterion, but the 7-day mean minimum and 30-day mean hydroelectric criteria were not 

exceeded during the 8 years sampled. 

DO profiles measured in Swan Falls reservoir in 2003 and 2004 showed mixed 

vertical DO conditions and longitudinal DO gradients. The longitudinal DO gradients 

suggested that settling and decay of inflow-suspended organic matter may cause a 

reduction of DO in the upper end of the reservoir, followed by increases in DO 

downstream to Swan Falls dam. 

The coldwater temperature criteria of a 22-degrees-Celsius (°C) daily maximum 

with a daily average of 19°C apply at both the inflow and outflow of the project. In 

addition, when natural background conditions exceed the numeric criteria, the numeric 

criteria no longer apply and temperature may not be increased above natural background. 

Water temperature measured in this reach of the Snake River can get very warm (i.e., 

>27°C), and temperatures exceeding the numeric criteria were measured at the Swan 

Falls inflow, outflow, and in-reservoir locations. The majority of exceedances occurred 

from mid-June through early September, although some exceedances occurred in late 

May 2003 and 2006. Temperature profiles collected in Swan Falls reservoir during 2003 

and 2004 showed nearly isothermal conditions (i.e., the temperature was the same at all 

depths), and there was no consistent pattern of warming or cooling over the length of 

the reservoir. 

Levels of pH in the project inflow and outflow during the monitoring period were 

generally similar, and the pH criterion of 6.5 to 9.0 was periodically exceeded at both 
34 

locations. Levels above 9.0 were most common, and coincided with periods of high 

primary productivity and low water conditions. 

TDG measurements made in 1999, when high levels of spill occurred, indicated 

that spill at Swan Falls dam does not generate excessively high TDG. TDG measured in 

spill flow immediately downstream of the spillway ranged from 104.0 percent to 112.4 

percent saturation. In June 1999 when spills greater than 19,000 cfs occurred, TDG was 

measured at 112.4 percent saturation directly below the spillway, while TDG in the 

turbine outflow measured 109.7 percent. Flow-weighting of these TDG measurements 

resulted in an average TDG of 111.2 percent saturation, which was the only occurrence of 

flow-weighted TDG exceeding the Idaho criterion of 110 percent saturation. 

Fishery Resources 

Fish Community 

Based on fisheries sampling conducted by Idaho Power in the project area (RM 

440–477) between 1989 and 2006, 9 native and 14 non-native species of fish occur in the 

project area (table 5). Fish species in the family centrarchidae (sunfishes) were the most 

commonly collected, followed by the families catostomidae (suckers) and cyprinidae 

(minnows). Smallmouth bass were consistently the most abundant centrarchids 

encountered during electrofishing surveys, and smallmouth bass and largescale suckers 

were ranked the top two species in abundance over all years sampled. The dominant 

species sampled within Swan Falls reservoir and between Swan Falls dam and Brownlee 

reservoir were the same and were collected in similar proportions (Richter and Chandler, 

2004). Anadromous fish species including Chinook salmon, steelhead trout, and Pacific 

lamprey have been blocked from accessing the project area since efforts to provide 

passage past the Hells Canyon Project (FERC Project No. 1971) were discontinued 

in 1964. 

White Sturgeon 

White sturgeon are the largest, longest-lived freshwater or anadromous fish in 

North America, and are highly adapted to the large river systems in which they evolved. 

Their large size and opportunistic behavior enabled them to range widely in order to take 

advantage of scattered and seasonally available resources in these dynamic river habitats 

and in the ocean. Longevity and high fecundity allowed them to persist through changes 

in their environment and capitalize on favorable spawning conditions when changes 

occurred, but their longevity and delayed maturation make them extremely vulnerable to 

overfishing. Long life span and benthic feeding also make sturgeon susceptible to 

bioaccumulation of pollutants with potentially detrimental effects on health, growth, 

maturation, and recruitment. 
35 

Table 5. Fish species collected in the project area during fisheries sampling 

conducted by Idaho Power (Source: Richter and Chandler, 2004, as 

modified by staff). 

Family Species 

Centrarchidae Black crappiea 

Bluegilla

Largemouth bassa

Pumpkinseeda

Smallmouth bassa 

White crappiea 

Warmoutha

Cyprinidae Chiselmouth 

Common carpa

Peamouth 

Northern pikeminnow 

Redside shinera

Ictaluridae Brown bullheada

Black bullheada

Channel catfisha 

Flathead catfisha

Salmonidae Rainbow trout 

Mountain whitefish 

Catostomidae Bridgelip sucker 

Largescale sucker 

Acipenseridae White sturgeon 

Cottidae Mottled sculpin 

Percidae Yellow percha a

 Non-native species 
36 

In addition, critical habitats of white sturgeon have been altered. The construction 

of dams has blocked movement and restricted white sturgeon to river fragments that may 

no longer provide the full spectrum of habitats necessary to complete their life cycles. 

Flow regulation has altered seasonal and annual fluctuations that provide behavioral cues 

and suitable spawning or rearing conditions. 

In the Snake River, the white sturgeon is classified by the state of Idaho as a 

species of special concern. Altered habitat, pollution, historical exploitation, and 

population fragmentation by dams have contributed to the current status of white 

sturgeon in the Snake River. Of the nine isolated subpopulations in the Snake River in 

Idaho, only the Hells Canyon downstream to Lower Granite and the Bliss downstream to 

C.J. Strike reaches support viable populations. In these reaches, abundance and 

population structure appear to be recovering from the effects of catch-and-keep fishing 

regulations that existed prior to 1972. However, Snake River reaches from Hells Canyon 

dam upstream to Swans Falls dam and from Bliss dam upstream to Shoshone Falls 

contain small populations and little or no detectable natural recruitment. 

Based on the scarcity of small sturgeon observed during the applicant’s surveys 

downstream of C.J. Strike dam and the recovery of sturgeon marked in the Bliss to C.J. 

Strike reach during sampling conducted downstream of C.J. Strike dam, it appears that 

the population of sturgeon downstream of C.J. Strike dam is supported by downstream 

movement of mid-sized and large white sturgeon from the population upstream of C.J. 

Strike dam. The most recent population estimates of adult sturgeon greater than 70 

centimeters long indicate that the species is present in the reaches upstream and 

downstream of the Swan Falls Project. Survey data from 2006 to 2007 indicate that there 

were 566 fish in the reach between C.J. Strike and Swan Falls dam (Lepla, 2008). Survey 

data from 1996 to 1997 report that there were 155 fish in the reach between Swan Falls 

dam and Brownlee reservoir (Idaho Power, 2008b). 

Comparing the current status of white sturgeon with the results of earlier Idaho 

DFG studies, white sturgeon abundance in the Swan Falls to Brownlee reach has changed 

little over the past 30 years. Some recruitment to the population still occurs based on the 

continuing presence of a few, small white sturgeon and documented spawning in 1997 

(Lepla and Chandler, 2001). However, the number of available female spawners in the 

population is low, and near-future recruitment will probably also remain low, perhaps 

below the levels necessary to sustain this population. Although the absence of small fish 

may partly result from the low number of adult fish downstream of Swan Falls, poor 

water quality has been identified as a possible cause of low recruitment. High nutrient 

loads have contributed to algae blooms and fish kills, including a substantial kill of at 

least 28 adult white sturgeon in Brownlee reservoir in 1990 (Idaho Power, 2008b). 
37 

Resident Salmonids 

Salmonids that may be present in the Swan Falls Project area include wild redband 

trout,22 hatchery-stocked rainbow trout, and mountain whitefish. Consistent with reports 

from the 1970s and later, very few observations of wild redband trout are associated with 

the Snake River in the Swan Falls area. Although redband trout are often cited as being 

tolerant of high water temperatures (Behnke, 1992; Zoellick, 1999), these references are 

generally associated with small stream systems with temperature fluctuations over a 24-

hour period that are often large. Because of its size, the Snake River has relatively minor 

temperature fluctuations, and within the project area, there are very few coldwater 

sources that offer temperature refuge. During monthly electrofishing surveys conducted 

by Idaho Power from October 2004 through March 2006, only four rainbow trout were 

sampled, with only one classified as wild. 

The mountain whitefish is a native salmonid that occurs throughout the Snake 

River and its tributaries. Mountain whitefish catches below Swan Falls dam have been 

relatively high in past surveys conducted by Idaho Power, and mountain whitefish made 

up a substantial portion of a large fish kill that occurred below Swan Falls dam in July 

2002. The fish kill was primarily the result of high water temperatures that occurred 

during a prolonged period of high summer air temperatures. A similar mountain 

whitefish kill occurred in the Swan Falls reach during July 1990. During monthly 

sampling of the project area from October 2004 to March 2006, Idaho Power collected a 

total of 49 mountain whitefish. 

3.3.2.2 Environmental Effects 

Water Quantity 

The current Swan Falls license, issued in 1982, requires instantaneous minimum 

flows downstream of the Swan Falls dam of no less than 5,000 cfs during the irrigation 

season (April 1 to September 30) and no less than 4,000 cfs outside of the irrigation 

season (October 1 to March 31). Currently, when the average inflow is less than 5,000 

cfs, Idaho Power limits headwater fluctuations to 0.4 foot, which facilitates compliance 

with minimum flows required by the Swan Falls Agreement, but also limits their ability 

to reregulate inflows from the C.J. Strike Project. Analysis of flow data from 1994 and 

2008, provided in Idaho Power’s January 5, 2009, response to the Commission staff’s 

 

22 The redband trout is a subspecies of rainbow trout native to Columbia River 

tributaries east of the Cascade Mountains, including the Snake River Basin as far 

upstream as Shoshone Falls. In the mid-Snake River region, populations of redband trout 

are thought to be limited currently to tributaries where natural reproduction occurs and 

where natural or human-made barriers have prevented interbreeding with non-native trout 

(Behnke, 1992). 
38 

additional information request (AIR), concludes that these low flow periods occurred 

about 3 percent of the time, almost exclusively between mid-June and mid-September. 

Idaho Power proposes to operate the project to provide an instantaneous minimum 

flow of 3,900 cfs downstream of the dam from April 1 to October 31 and 5,600 cfs from 

November 1 to March 31, consistent with the Swan Falls Agreement. The ramping rate 

restrictions would continue to be no more than 1 foot per hour and 3 feet per day. 

Our Analysis 

Idaho Power conducted an instream flow study to assess the effects of project 

operation on white sturgeon and whitefish habitat in the reach downstream of Swan Falls 

dam. The results of the study (Brink, 2008) indicate that flow fluctuations caused by 

current project operations have minor to moderate effects on habitat for these species. 

The analysis was conducted using hydrology from representative low, medium, and high 

flow years, and assessed the amount of daily variation in habitat for six lifestages of 

sturgeon and four lifestages of mountain whitefish, expressed as weighted usable area. 

Study results indicate that under current operations, the daily variation in the 

amount of habitat available for white sturgeon spawning is 0.41 to 8.1 percent in a low 

flow year, 0.36 to 9.5 percent in a medium flow year, and 0.0 to 18.8 percent in a high 

flow year. Daily variation in habitat available to juvenile white sturgeon is 0.0 to 0.69 

percent in low and medium flow years and in high flow years averages about 14 percent 

until flows exceeded 20,000 cfs, when the amount of suitable habitat drops to zero. For 

the incubation, larvae, young-of-year and adult lifestages of white sturgeon, daily 

fluctuations in habitat availability are less than 5 percent in all year types. Daily 

variations in habitat availability for all four lifestages of whitefish (spawning, fry, 

juveniles and adults) are less than 6 percent in all water year types. 

The proposed change in minimum flows would ensure compliance with the 

minimum flows specified in the Swan Falls Agreement, and also improve Idaho Power’s 

ability to re-regulate inflows from the C.J. Strike Project. This would reduce the extent 

of daily variations in streamflows discharged from the project during those times when 

inflows range between 3,900 cfs and 5,000 cfs, and thereby reduce the daily variations in 

habitat for all lifestages compared to current operations. As discussed earlier, under the 

current license, Idaho Power must limit reservoir fluctuations to no more than 0.4 foot 

when daily average inflow falls below 5,000 cfs. This effectively eliminates Idaho 

Power’s ability to reregulate variable inflows to the project when inflows are less than 

5,000 cfs. By lowering the minimum flow requirement to 3,900 cfs, Idaho Power could 

reregulate inflows to the project, and thereby reduce daily discharge variations, during 

those times when inflows are as low as 3,900 cfs. 

For white sturgeon spawning and early lifestages, larvae and young-of-year are the 

only lifestages that occur during the mid-June to mid-September time period when flows 

may be reduced compared to current operations. The results of Idaho Power’s instream 

flow study indicate that the amount of habitat for sturgeon incubation and young-of-year 
39 

would be reduced by 41.6 percent and 11.4 percent, respectively, at a flow of 3,900 cfs 

compared to the current minimum flow of 5,000 cfs. However, Idaho Power’s studies of 

white sturgeon populations in the Snake River indicate that successful spawning and 

recruitment of sturgeon occurs primarily in high water years (Idaho Power, 2008b), when 

flows lower than 5,000 cfs are not likely to occur. As a result, any effects of the reduced 

minimum flow on sturgeon recruitment are unlikely. Habitat for juvenile and adult 

sturgeon would increase by 2.2 percent and habitat for adult sturgeon would decrease by 

1.9 percent. 

The mountain whitefish spawning and the fry lifestages do not occur during the 

mid-June to mid-September time period when outflows may be reduced under proposed 

minimum flows. Habitat available for juvenile and adult whitefish may be reduced by up 

to 12.3 and 4.1 percent, respectively, at the proposed minimum flow of 3,900 cfs. Given 

the low frequency of occurrence of flows below 5,000 cfs (less than 3 percent of the 

time), and the reduced expected level of flow fluctuations, we any effects on mountain 

whitefish would likely be minor. 

During the non-irrigation season (October 1 to March 31), the higher minimum 

flow proposed by Idaho Power (5,600 cfs compared to the current minimum flow of 

4,000 cfs) would increase the amount of habitat available to most lifestages of white 

sturgeon and whitefish that occur in this time period. Habitat for white sturgeon youngof-year and adult lifestages would increase by 15.9 and 2.5 percent, respectively, while 

habitat for juvenile sturgeon would decrease by 1.7 percent. For mountain whitefish, 

habitat available for spawning, fry, juvenile and adult lifestages would increase by 25.4, 

129.5, 31.1, and 10.8 percent, respectively. 

Continuing to operate the project to re-regulate outflows from the C.J. Strike 

Project would continue to protect downstream habitat from the effects of large flow 

fluctuations associated with peaking operations at C.J. Strike. Based on the habitat 

modeling results discussed above and the low incidence of flows in the range that would 

be affected by the proposed change in minimum flows, we find that any adverse effects 

of proposed project operations on white sturgeon and whitefish would likely be 

very minor. 

Water Quality 

Idaho Power proposes two water quality measures: (1) continue operation of the 

trash rake over the turbine intakes to remove aquatic macrophytes and debris from the 

river; and (2) monitor temperature and DO in the outflow from Swan Falls dam. The 

purpose of monitoring would be to document and report the temperature and DO 

conditions of the Swan Falls outflow to Idaho DEQ. An automated system would be 

installed and operated to electronically store measurements every 10 minutes. 

Temperature and DO would be monitored from June 15 through October 5, and data 

would be summarized for reporting on a monthly basis. The specific location of the 
40 

system would be determined through the section 401 WQC process with Idaho DEQ. 

Idaho DFG recommends implementing these measures. 

In its WQC, Idaho DEQ specifies that Idaho Power develop a monitoring plan in 

consultation with and approved by Idaho DEQ, to determine the effect, if any, of the 

project on water quality both within the reservoir and downstream of Swan Falls dam. 

The plan would describe the location and method of monitoring discharge, water 

temperature, DO, and TDG in the project inflow and outflow.23 The plan would 

incorporate a quality assurance control plan with appropriate protocols for measuring 

these parameters, including continuous flow monitoring. The WQC also specifies that 

Idaho Power submit annual data reports to Idaho DEQ. After 5 years, Idaho Power could 

request termination of some or all of the monitoring components, except those that are 

proposed in its license application. 

Our Analysis 

Large amounts of macrophytes and macroalgae are routinely removed from the 

trash racks in front of the turbine intakes by using a trash rake and filling a dump truck 

(310 and 207 truck loads in 2005 and 2006, respectively). Coarse particulate organic 

matter sampling data indicate that inflowing nutrients associated with drifting coarse 

particulate organic matter, such as macrophytes and macroalgae, comprised 5 percent of 

the total inflow total phosphorus load and 12 percent of the total inflow particulate 

phosphorus (particulate P) load passing Swan Falls dam in 2004 (Naymik and Hoovestal, 

2008). Continuing the practice of removing vegetation from the trash racks would 

continue to reduce the amount of floating or submerged matter, excess nutrients, and 

oxygen-demanding material that would otherwise pass downstream and contribute to the 

low DO concentration. Macrophyte and macroalgae removal in conjunction with 

implementation of the phosphorus TMDL (see Affected Environment for more 

information) would continue to help reduce adverse water quality conditions in Swan 

Falls reach and in Brownlee reservoir downstream. 

Currently, project operations can result in minor exceedances of the state of 

Idaho’s 110-percent saturation standard when spills occur at the project. As discussed 

above, proposed minimum flow changes would improve coordination of operations and 

reregulation of outflows from the C.J. Strike Project; therefore, there would likely be a 

reduction in the incidence of spill flows and exceedances of the TDG standard. 

Monitoring water temperature and DO at the outflow from the project, as proposed 

by Idaho Power, would assist with monitoring progress toward improving water quality 

conditions in the Snake River at and downstream of the Swan Falls Project, which has 

experienced adverse DO and temperature conditions that were associated with fish kills 

observed in 1990 and 2002, and documenting the expected beneficial effect of proposed 

 

23 Idaho DEQ states that TDG monitoring is needed to help determine the effects, 

if any, of the project on water quality within and downstream of the project. 
41 

changes in operation on TDG exceedances. Monitoring discharge, water temperature, 

DO, and TDG at the project inflow and outflow for a minimum of 5 years after license 

issuance, as specified in the WQC, would help determine the effectiveness of the 

macrophyte and macroalgae removal in conjunction with other measures that are 

implemented to reduce phosphorus loads through the TMDL, and confirm that changes in 

project operations associated with proposed minimum flow changes would not cause 

adverse effects on water quality, including water temperature, DO, and TDG. Inclusion 

of information on project inflow and outflow amounts in monitoring reports as specified 

in the WQC should not require the installation of any new gages, because Idaho Power 

already monitors outflows from the Swan Falls and C.J. Strike projects, and no 

substantial inflows occur between the two projects. 

Sturgeon Entrainment and Impingement 

Between 1996 and 2008, approximately 59 dead adult sturgeon were sighted or 

recovered from the reach between C.J. Strike dam and Swan Falls dam, including 35 

sturgeon that were recovered from the trash rack at the Swan Falls intake. Idaho Power 

has undertaken several measures to reduce the potential for sturgeon being injured or 

killed during start-up of the turbines at the C.J. Strike powerhouse, and has undertaken 

monitoring activities designed to determine the source of these sturgeon mortalities. 

Idaho Power does not propose any measures to address the potential for entrainment or 

impingement of white sturgeon at the project. Idaho DFG indicates that it supports the 

efforts that are being undertaken to reduce injury or mortality of adult sturgeon associated 

with turbine start-up at the C.J. Strike Project, and did not recommend any fish 

entrainment or impingement-related measures at the Swan Falls Project. 

Our Analysis 

In its January 5, 2009, additional information response, Idaho Power provided a 

detailed summary of turbine injuries and mortalities that have been observed in the reach 

between the C.J. Strike and Swan Falls projects. Many of the injuries have been 

documented to occur during start-up of the turbines at the C.J. Strike powerhouse, and 

many of the dead sturgeon have exhibited evidence of being struck by turbine blades. In 

2000, Idaho Power began using compressed air blasts prior to unit start-ups in an effort to 

“clear” white sturgeon out of the C.J. Strike Project draft tubes and away from the 

turbine blades. 

Although this measure initially appeared to be effective in eliminating sturgeon 

injuries during turbine start-up, between April 27 and May 17, 2004, a total of 13 white 

sturgeon carcasses were recovered from the forebay of Swan Falls dam. Seven of the 

white sturgeon had various external physical injuries, ranging from minor cuts and 

abrasions along the body to damaged pectoral/caudal fin-body joints and one head 

fracture. Although the causes and events surrounding these mortalities remain unclear, 

Idaho Power has concluded that environmental conditions such as low DO levels, 

temperature, or chemical toxins are unlikely to have been factors. Given the uncertainty 
42 

of the causes of sturgeon mortalities that occurred in 2004, Idaho Power installed a large 

capacity air blower in the C.J. Strike Project draft tubes between 2004 and 2005; the air 

blower is used to push the water level in the draft tubes to a level below the turbine 

blades prior to turbine start-up to eliminate the potential for sturgeon to come into contact 

with the turbines during start-up. 

Despite implementing this additional measure, another large mortality event 

occurred between April 13 and May 20, 2006, when 11 adult white sturgeon carcasses 

were recovered at the Swan Falls trash rack. No cause of death for any of the 11 fish was 

apparent. Although the timing, number, and lifestages of the 11 fish were similar to the 

2004 mortality event, project operations at C.J. Strike dam and the river’s hydrograph 

were very different. During 2004, there were no spill events at C.J. Strike dam, and 

project units were cycled daily to meet power demands. In contrast, C.J. Strike dam was 

spilling water in 2006 and all project units were on-line continuously for upwards of one 

month, yet 5 out of the 11 sturgeon mortalities that occurred during 2006 were recovered 

at the Swan Falls trash rack during this period. This indicated that these mortalities were 

not caused by unit starts but by some other, unknown source(s). Even so, as an additional 

measure of safety, Idaho Power installed a sensor to prevent the C.J Strike Project 

turbines from starting if a unit had not been fully compressed with air. 

To gain more information on the potential causes of sturgeon mortality, Idaho 

Power has been attaching transmitters on large, reproductive adult sturgeon since 2006 to 

monitor their locations during the spawning season. In addition, operators at C.J. Strike 

dam inspect the tailrace during unit starts during the spawning season to see if any deaths 

are caused by the project. Idaho Power also conducted a diver inspection of the outer 

draft tubes and turbine spillway to inspect for sharp objects or surfaces that may injure 

sturgeon as they exit the draft tubes or pass over the spillway. Following these 

inspections, Idaho Power removed steel ladders that were attached to the draft tube walls, 

along with several pieces of pipe that were protruding from the spillway. 

In its additional information response, Idaho Power states that it believes that the 

measures it has implemented will ensure that restarting project units at C.J. Strike dam 

will not kill white sturgeon. Idaho Power also states that it will continue to coordinate its 

work with the regional Idaho DFG office and the White Sturgeon Technical Advisory 

Committee (WSTAC) to assess the causes of turbine mortality events and determine 

whether additional measures are needed. 

The results of monitoring efforts to date do not indicate that any of the sturgeon 

injuries and mortalities that have been observed are associated with operation of the 

Swan Falls Project, and it appears that most if not all of the sturgeon that have been 

recovered from the trash rack at Swan Falls dam were dead at the time that they became 

impinged on the rack. Although it is possible that some smaller sturgeon are entrained 

into the intake at Swan Falls dam and may be subject to possible injury or mortality 

during passage through the project turbines, the number of sturgeon that may be subject 
43 

to injury from entrainment is limited by the scarcity of smaller sturgeon in the reach 

between the C.J. Strike and Swan Falls projects. 

White Sturgeon Conservation Plan 

Idaho Power developed the White Sturgeon Conservation Plan (Idaho Power, 

2008b) as a means of developing and implementing protection, mitigation, and 

enhancement measures directed at white sturgeon populations to address the effects of its 

mainstem Snake River hydroelectric projects. Additionally, the WSTAC was established 

in 1991 to provide technical guidance for white sturgeon research activities undertaken 

by Idaho Power during relicensing efforts. Since its formation, representatives from 

state, federal, and tribal entities have participated in WSTAC meetings to review study 

results and resource issues affecting Snake River white sturgeon. 

The White Sturgeon Conservation Plan describes Snake River white sturgeon 

measures and strategies that Idaho Power would implement once the plan was approved 

and new project licenses were issued by FERC. Several measures are designed to assess 

factors that may be limiting the population of white sturgeon in the reach between Swan 

Falls dam and Brownlee dam, the latter of which is the most upstream of the three dams 

in the Hells Canyon Project. Idaho Power proposes to implement these measures under a 

new license for the Hells Canyon Project.24

Although none of the measures included in the White Sturgeon Conservation Plan 

are proposed for inclusion in any license for the Swan Falls Project, the water quality 

measures discussed in the preceding section, Water Quality, would benefit white 

sturgeon. These include: (1) continue to remove and dispose of aquatic macrophytes and 

debris that accumulate on the project trash racks to remove nutrients and oxygendemanding material from the river; and (2) implement a water temperature and DO 

monitoring program to document and report the temperature and DO conditions of the 

Swan Falls outflow. 

In the State of Idaho’s letter filed August 14, 2009, Idaho DFG stated that it 

supports the vegetation removal and water quality monitoring measures proposed by 

Idaho Power. The agency also provided recommendations on several measures in the 

White Sturgeon Conservation Plan pertaining to the reach between Swan Falls and 

Brownlee dams. Idaho DFG stated its support for implementing the proposed study of 

water quality impacts and the White Sturgeon Conservation Plan’s provision for the 

translocation of sturgeon into the Swan Falls to Brownlee reach, and stated that it does 

not object to investigating the development of a conservation hatchery program under the 

conservation plan, but recommended that additional details on the proposals be 

 

24 See Idaho Power’s license application for the Hells Canyon Hydroelectric 

Project, FERC No. 1971, filed on July 21, 2003. The Commission staff’s final EIS was 

issued on August 31, 2007. The Commission has not yet issued its decision on Idaho 

Power’s Hells Canyon license application. 
44 

developed, including: (1) providing additional detail on where the on-site and laboratory 

facilities used to assess water quality impacts on early sturgeon lifestages would be 

located, how they would be operated, and who would operate them; (2) indicating how 

many fish would be translocated during each phase of the translocation program; and 

(3) if the hatchery option is pursued, preparing a broodstock and genetic management 

plan and marking or tagging any hatchery fish for identification. 

Our Analysis 

Historically, white sturgeon were abundant in the Snake River. Mainstem dams 

on the Snake River block the upstream movement of white sturgeon, which historically 

were able to migrate throughout much of the Snake and Columbia rivers and their major 

tributaries to access suitable spawning habitats and to take advantage of seasonally 

abundant food resources. Sturgeon populations have also been adversely affected by 

alteration of the hydrograph, flow diversions for irrigation, and reduced water quality 

associated with flow diversion and nutrient inputs from agricultural and municipal 

sources. Currently, federal and state agencies, Tribes, and non-government organizations 

have been taking actions to increase sturgeon populations in the project area. 

Idaho Power’s proposal to continue removing vegetation that accumulates on the 

trash racks at the Swan Falls Project and to monitor the DO and temperature of the 

outflow of the Swan Falls Project would contribute to improving water quality in the 

Snake River downstream of the project, which would benefit sturgeon populations by 

improving conditions for white sturgeon rearing and reproduction. These proposed 

measures would complement other measures included in the White Sturgeon 

Conservation Plan for determining whether white sturgeon reproduction is limited by 

water quality conditions and helping determine appropriate methods for rebuilding white 

sturgeon populations in the reach between Swan Falls and Brownlee dams. As noted 

above, Idaho Power proposes to implement these additional measures of the conservation 

plan under a new license for the Hells Canyon Hydroelectric Project as opposed to any 

new license for the Swan Falls Project. 

Resident Fish Monitoring 

Idaho Power proposes to monitor the population of resident fish species in Swan 

Falls reservoir and the 15-mile reach downstream of Swan Falls dam every 5 years in the 

spring and fall using boat-mounted electrofishing gear. Basic population characteristics, 

such as species enumeration, relative abundance, condition, and proportional stock 

density would be assessed. Idaho DFG recommends implementation of this measure. 

Our Analysis 

The proposed monitoring program would enable identification of long-term trends 

in fish populations in the project area. Although this information could be used in the 

decision-making process of federal and state resource agencies charged with fisheries 

management in the project area, the proposed monitoring is not designed to detect the 

effects of any specific project-related action, such as operations or maintenance activities, 
45 

and therefore, would be too broad to be of any benefit as it relates to the project.25 

Moreover, resident fish monitoring, even if tied to project actions, would be of little 

benefit because proposed project operations, as discussed above, would improve the 

project area fishery by reducing daily variations in habitat for all lifestages of fish species 

in the project area. We base this finding on already existing site-specific information on 

the relationships between project operations and fish habitat, negating the need for any 

additional study. 

3.3.2.3 Cumulative Effects 

Construction of the Swan Falls Project likely contributed to cumulative effects on 

water quality by increasing water transit time and primary production during low-flow 

periods. Idaho Power’s proposal to continue to remove aquatic vegetation and other 

debris that accumulate on the project’s trash racks would continue to help improve water 

quality in the Snake River downstream of the project. 

Construction of Swan Falls dam contributed to cumulative effects on white 

sturgeon by precluding upstream passage, which prevents white sturgeon from moving 

freely throughout the river to make use of suitable spawning and rearing habitats. 

Continuing to remove aquatic vegetation and other debris that accumulate on the projects 

trash racks would continue to improve water quality conditions for the white sturgeon. 

3.3.3 Terrestrial Resources 

3.3.3.1 Affected Environment 

Vegetation 

Historical land use patterns—primarily livestock grazing and irrigation for 

agriculture—have substantially altered the sagebrush-steppe plant communities that once 

dominated the Snake River Plain and canyon. Invasive weeds were introduced in the late 

1800s, and by the 1930s, cheatgrass had become widespread. A nearly continuous carpet 

of this exotic winter annual grass has increased the frequency and intensity of wildfires, 

which in turn have reduced shrub cover and created the disturbed conditions that foster 

the spread of additional non-native species. Wind, river flows, and animal transport have 

continued to contribute to weed dispersion over time, and human activities have also 

played an important role. 

 

25 Designing a site-specific study to detect the specific effects of project operations 

on fish populations would be extremely difficult, if not impossible, due to many 

confounding factors, such as the adverse effects of upstream hydropower and water 

storage operations, irrigation withdrawals and returns, and variable drought and 

flood events. 
46 

Vegetation Cover Types 

Idaho Power evaluated current vegetation patterns by analyzing aerial 

photographs, conducting vegetation surveys, and developing cover type maps of a 

12,045-acre study area that covered land and water below the canyon rim within 0.5 mile 

of the reservoir or river centerline from RM 471 downstream to Guffey Bridge at RM 

447.2 (Krichbaum et al., 2008). The existing Swan Falls Project boundary encompasses 

almost 2,192 acres, including 1,255 acres of land and 937 acres of water. Based on Idaho 

Power’s cover type mapping, shrub-dominated uplands account for about 765 acres, and 

herbaceous cover types (those dominated either by grasses or forbs) account for about 

165 acres. Riparian vegetation comprises approximately 208.6 acres of land within the 

project boundary, including 109.6 acres of emergent wetland, 6.3 acres of shore and 

bottomland wetland, 63.6 acres of scrub-shrub wetland, and 29.1 acres of forested 

wetland. Other cover types in the project area include cliffs and talus slopes, pasture and 

agriculture, parks and recreation, developed lands, and barren lands. 

Idaho Power found that the most common plants within the shrub cover types are 

big sagebrush, yellow rabbitbrush, greasewood, and various saltbush species, with a grass 

layer dominated by cheatgrass. Cheatgrass is a dominant species in the herbaceous cover 

types as well, but patches of native grasses also are present in significant amounts in 

some areas. 

Shrub cover types dominate the transmission line right-of-way. Where the rightof-way crosses benchland above the cliffs, the most common species are big sagebrush, 

winterfat, cheatgrass, and tall tumblemustard. Below the cliff, cheatgrass and prickly 

Russian thistle are common, with scattered saltbush species. One wet, mossy slope 

supports native bunchgrasses, but otherwise, there is no riparian or wetland habitat along 

the transmission line right-of-way. 

Riparian cover types are associated primarily with reservoir and river shorelines. 

In the emergent wetlands, the most common species are reed canarygrass, knotgrass, 

hardstem bulrush, broadleaf cattail, and saltgrass. In the scrub-shrub wetlands, the 

dominant species are coyote willow and Russian olive. The forested wetland cover type 

supports a mix of trees, including Pacific willow, netleaf hackberry, silver maple, 

boxelder, black locust, and Russian olive. Most of the shore and bottomland wetlands are 

dominated by hardstem bulrush and knotgrass, but patches of this cover type support a 

mix of shrubs, such as coyote and other willow species, Woods’ rose, and Russian olive, 

and only scattered forbs and grasses. 

Noxious Weeds and Invasive Plant Species 

Idaho Power conducted noxious weed surveys within the 12,045-acre study area 

described above. To cover this large acreage, Idaho Power used a sub-sampling to 

investigate the occurrence, distribution, and abundance of weeds along shorelines, on 

islands, and in areas where roads, campsites, and trails could affect the introduction and 
47 

spread of weeds. Along the shorelines, surveyors recorded the elevation of occurrences 

in relationship to the OHWM in 6-inch increments, or height-classes. 

The surveys documented 14 invasive species in 983 separate populations (table 6). 

At least three weed species were observed in every survey unit. Most populations (707) 

were observed along the shoreline, while 213 were observed in disturbed areas, and 63 

were recorded on islands. Surveyors found the most abundant weed species to be 

Russian olive, whitetop and broadleaved pepperweed, with purple loosestrife, reed 

canarygrass, saltcedar, common thistle, and puncturevine also common. Rush 

skeletonweed, field bindweed, Scotch cottonthistle, jointed goat grass, and spotted 

knapweed were observed, but only in scattered locations. 

Idaho Power conducted noxious weed surveys along the entire transmission line 

and associated service road right-of-way, rather than using the sub-sampling method that 

was applied to the larger study area. Surveyors documented whitetop and puncturevine. 

Surveyors considered whitetop to be locally abundant in the road corridor, but 

puncturevine was less prevalent. 

Table 6 summarizes weed abundance and distribution, but it is important to note 

that the surveys relied on a sub-sampling approach to cover a large area, and because 

weeds are very widespread in the Swan Falls Project vicinity, not all existing weed 

occurrences were documented during the surveys. 

Table 6. Noxious and invasive non-native weed species documented in the Swan 

Falls study area and within or adjacent to the project boundary (Source: 

Krichbaum, 2008a, as modified by staff; Vistine-Amdor et al., 2009, as 

modified by staff). 

Weed Species 

Populations 

Documented in 

the Upstream 

Study Area 

Populations 

Documented in 

the Downstream 

Study Area 

Populations Within 

or Immediately 

Adjacent to the 

Project Boundary 

Russian olive 

(Elaeagnus angustifolia) 

95 90 Not mapped a

Whitetop 

(Cardaria draba) 

81 85 104 

Broad-leaved pepperweed 

(Lepidium latifolium) 

94 48 44 

Purple loosestrife 

(Lythrum salicaria) 

65 73 69 

Reed canarygrass 

(Phalaris arundinacea) 

65 52 Not mappeda
48 

Weed Species 

Populations 

Documented in 

the Upstream 

Study Area 

Populations 

Documented in 

the Downstream 

Study Area 

Populations Within 

or Immediately 

Adjacent to the 

Project Boundary 

Saltcedar 

(Tamarix pentandra) 

31 53 51 

Canada thistle 

(Cirsium arvense) 

43 28 28 

Puncturevine 

(Tribulus terrestris) 

27 19 17 

Skeleton-weed 

(Chondrilla juncea) 

4 5 3 

Field morning glory 

(Convolvulus arvensis) 

5 3 6 

Scotch thistle 

(Onopordum acanthium) 

3 4 0 

Russian knapweed 

(Centaurea repens) 

5 2 2 

Goat grass 

(Aegilops cylindrica) 

2 0 2 

Spotted knapweed 

(Centaurea maculosa) 

0 1 1 

Total 520 463 327 a

 Invasive non-native species that are not designated as noxious weeds were not 

mapped as part of Idaho Power’s development of the Noxious Weed Management 

Plan (Vistine-Amdor et al., 2009). 

Special Status Plants 

The study area for special status plants (i.e., species listed as threatened, 

endangered, proposed, or candidates for listing at the federal level; designated as 

sensitive by the BLM; or considered to be of conservation concern in the state of Idaho) 

mirrored the noxious weed survey area, and Idaho Power used the same sampling design 

to investigate occurrence, distribution, and abundance. Surveyors documented 90 

populations of nine different species within the study area (table 7). Five special status 

plants (Snake River milkvetch, desert pincushion, white eatonella, giant helleborine, and 

western germander) were documented within the project boundary. 

In addition to surveying the shorelines, islands, and disturbed areas, Idaho Power 

conducted rare plant surveys along the transmission line and associated service road 
49 

right-of-way. Surveyors did not observe any rare plants during these surveys. The 

nearest documented rare plant occurrence is a population of Shockley’s buckwheat 

(Eriogonum shockleyi S. Wats. var. shockleyi) that grows on the canyon rim 

approximately 500 feet from Tower 4. 

Table 7. Special status plant species documented in the Swan Falls study area and 

within the project boundary (Source: Krichbaum, 2008b; Carpenter et al., 

2008, as modified by staff). 

Special Status Plant 

Species 

Populations 

Documented 

in the 

Upstream 

Study Area 

Populations 

Documented 

in the 

Downstream 

Study Area 

Total 

Number of 

Populations 

Populations 

within the 

Project 

Boundary 

Mulford’s milkvetch 

(Astragalus mulfordiae) 

0 4 4 0 

Snake River milkvetch 

(Astragalus purshii var.

ophiogenes) 

11 15 26 13 

Desert pincushion 

(Chaenactis stevioides) 

13 0 13 2 

White eatonella 

(Eatonella nivea) 

1 1 2 1 

Giant helleborine 

(Epipactis gigantea) 

2 0 2 1 

White-margined wax 

plant (Glyptopleura 

marginata) 

4 0 4 0 

Rigid threadbush 

(Nemacladus rigidus) 

0 1 1 0 

Turtleback 

(Psathyrotes annua) 

2 0 2 0 

Western germander 

(Teucrium canadense

var. occidentale) 

30 6 36 27 

Total 63 27 90 44 

Two of the nine special status plants documented in the study area occur within 

riparian habitat. These species—western germander and giant helleborine—grow in 
50 

moist, saturated, or inundated soils, where changes in project operation would have the 

potential to affect hydrology that supports these plants. 

Surveyors observed 30 populations of western germander along the reservoir 

shoreline, and 6 populations growing along the Snake River shoreline downstream of the 

dam. Most of the reservoir populations (77 percent) were found along the lower end of 

the reservoir, where they are exposed to minimal water surface fluctuations that result 

from operation of the C.J. Strike Project. Reservoir populations were also the largest of 

those documented, and three times as many individual plants were found on the northeast 

side of the river as were found on the southwest side. 

The six western germander populations documented along the river shoreline, 

flats, and side channels occurred at various elevations. These ranged from the OHWM or 

a little below to 11 height classes above the OHWM and up to 9 feet laterally from the 

shoreline, but most were closely associated with the shoreline. 

One population of giant helleborine was noted along the reservoir shoreline, 

between three and seven height classes above the OHWM and from 1.5 to 3 feet laterally 

from the shoreline. The other population was associated with a hillside seep, well above 

the shoreline. 

Wildlife 

In describing existing conditions for wildlife, Idaho Power considered the same 

study area as defined for botanical resources (i.e., lands below the canyon rim within 

0.5 mile of the reservoir or river centerline, from RM 471 to RM 447.2). The entire study 

area is located within the Snake River Birds of Prey NCA. 

Birds 

The Snake River Birds of Prey NCA supports one of the highest densities of noncolonial nesting raptors in the world. Numerous studies have been conducted within the 

NCA since the 1960s. Twenty-five raptor species use the NCA during some portion of 

their life cycles, and all can be found within the Swan Falls study area. Sixteen species 

nest in the canyon, and nine occur as migrants or winter residents. The most common 

diurnal raptors are prairie falcon, golden eagle, red-tailed hawk, American kestrel, and 

northern harrier. During migration and in the winter, common species include osprey, 

bald eagle, rough-legged hawk, sharp-shinned hawk, and Cooper’s hawk. Seven species 

of owls may also be present. 

No studies within the NCA have focused on upland game birds, but the same 

species are likely to be present in the Swan Falls Project area as those observed during 

studies associated with relicensing of the C.J. Strike Project, located about 36 miles 

upstream of the Swan Falls dam. Based on habitat similarities between the two areas, it 

is likely that California quail, mourning dove, ring-necked pheasant, and gray partridge 
51 

are most common (Sunderman et al., 1997a). Idaho Power staff also observed chukars in 

the Swan Falls vicinity. 

Two studies conducted within the NCA during the 1990s focused on the habitat 

relationships of shrubland bird species. Based on these studies, nine of the most common 

shrubland and grassland species include long-billed curlew, horned lark, grasshopper 

sparrow, lark sparrow, western meadowlark, Brewer’s sparrow, sage sparrow, whitecrowned sparrow, and sage thrasher. 

No studies have specifically focused on riparian bird communities within the 

NCA, but species are likely similar to those described for the C.J. Strike Project, where 

habitats are similar. Idaho Power found that seven bird species were common in the C.J. 

Strike Project area, including mallard, red-winged blackbird, black-billed magpie, 

yellow-rumped warbler, white-crowned sparrow, northern flicker, and song sparrow 

(Holthuijzen, 1997a). Species diversity was highest in the spring and declined through 

the fall and winter, but bird densities were highest in the winter. 

No waterfowl surveys have been conducted in the study area downstream of Swan 

Falls dam, but a total of 26 waterfowl species were documented as using the Snake River 

between Swan Falls dam and C.J. Strike dam (Holthuijzen, 1997b). American coots were 

most common, followed by mallard, common goldeneye, American wigeon, Canada 

goose, common merganser, bufflehead, and teal. Birds numbers increased from 11 birds 

per river mile in September to 110 birds per river mile in January, and then dropped 

through March to 57 birds per river mile. Riverine conditions in the narrow canyon 

below Swan Falls dam would likely be most conducive to diving ducks (e.g., common 

goldeneye and common merganser), while conditions would favor dabbling ducks 

(e.g., mallards and American wigeon) and surface dippers (e.g., American coot) where 

the river widens and passes through agricultural areas below Walters Ferry. 

The Deer Flat National Wildlife Refuge (Refuge) provides important habitat for 

numerous species of waterbirds along the Snake River downstream of the Swan Falls 

Project. Established in 1909, the Refuge includes the 10,588-acre Lake Lowell sector, 

and about 800 acres on 101 islands. The islands are distributed along 113 miles of the 

Snake River from approximately the Guffey Bridge downstream to Farewell Bend. The 

two refuge islands located closest to the Swan Falls Project, Rail and Sign islands, are 

located about 10 miles downstream of the dam, outside of the existing and proposed 

project boundaries. 

The American Bird Conservancy has identified the Refuge as a Globally 

Important Bird Area, based on the large concentrations of waterfowl that use the Refuge 

for breeding, overwintering, and resting during migration. 

Mammals 

Small and medium-sized mammals in the Swan Falls Project area include Piute 

ground squirrels and black-tailed jackrabbits, both of which are the primary prey of many 

raptor species. Piute ground squirrels are found on the benchlands on the north side of 
52 

the Snake River in the NCA. Black-tailed jackrabbits occur throughout the NCA. 

Mountain cottontail and yellow-bellied marmot are also present within the canyon. A 

variety of mice, chipmunks, and woodrats are also present, and 10 bat species have 

been reported. 

Furbearers and predators that use the benchlands and canyon include the coyote, 

badger, eastern spotted skunk, striped skunk, raccoon, mink, bobcat, long-tailed weasel, 

river otter, mountain lion, beaver, and muskrat. Coyotes, bobcats, and mountain lions 

would be likely to use all habitats that are available. Badgers are strongly associated with 

uplands, and studies in the NCA in the mid-1970s estimated the density of badgers at 2 to 

6 per square kilometer. Skunks, raccoons, river otter, beaver, and muskrat are typically 

associated with riparian habitats. 

Mule deer and pronghorn are the most common big game species in the NCA 

(BLM, 2006). BLM estimates that more than 100 resident mule deer and approximately 

50 resident pronghorn occupy the area along the Snake River in the NCA. 

Reptiles and Amphibians 

Seventeen reptile species are found in the NCA. The most abundant snake species 

are night snakes and western rattlesnakes, but Great Basin gopher snakes are also 

frequently observed. The most commonly-encountered lizards are the side-blotched 

lizard and the western fence lizard. 

Despite the dry conditions, the NCA supports at least seven amphibian species. 

These include the Great Basin spadefoot, western toad, Woodhouse’s toad, western and 

Pacific chorus frogs, northern leopard frog, and the invasive bullfrog. 

Special Status Wildlife 

Idaho Power developed a list of 52 special status wildlife species that are known to 

occur or may be present in the Swan Falls Project area, including species that FWS or 

Idaho DFG has identified as threatened, endangered, proposed or candidates for listing, 

and those that BLM or Idaho DFG has designated as sensitive, rare, or in need of special 

management. 

As a means of focusing its evaluation of the effects of project-related activities 

(including maintenance, road traffic, and recreation) on special status species, Idaho 

Power selected 26 species to represent various habitats. Table 8 shows how the species 

were grouped and their occurrence in the Swan Falls study area. 
53 

Table 8. Species groups used to evaluate the effects of project-related activities in 

the Swan Falls study area (Source: Carpenter et al., 2008, as modified by 

staff). 

Species Group 

Focus 

Habitat Species 

Season 

Present 

Shrubland birds Shrubland Brewer’s sparrow, sage sparrow, 

sage thrasher, black-throated sparrow 

Spring, 

summer 

Shrubland 

herptiles 

Shrubland Night snake, Woodhouse’s toad, 

longnose snake 

Year-round 

Grassland 

herptiles 

Grassland Woodhouse’s toad, longnose snake Year-round 

Riparian dwellers Riparian Brewer’s blackbird, common garter 

snake, western toad, northern leopard 

frog, Woodhouse’s toad, longnose 

snake 

Spring, 

summer 

Shorebirds Shoreline Wilson’s phalarope, great egret Spring, 

summer 

Winter raptors Riparian Northern goshawk, bald eagle Winter 

Winter 

waterbirds 

River and 

reservoir 

Bald eagle, Barrow’s goldeneye, 

trumpeter swan 

Winter 

Cliff dwellers Cliff Ferruginous hawk, prairie falcon, 

Yuma myotis, western pipistrelle, 

Townsend’s big-eared bat, smallfooted myotis, spotted bat 

Year-round 

Talus reptiles Cliff base Great Basin collared lizard, western 

ground snake, night snake 

Year-round 

Idaho Power evaluated the risk of recreational disturbance (including activity 

associated with roads and parks, as well as dispersed recreation) on these groups of 

special status species through the use of Geographic Information System (GIS) modeling 

(Carpenter et al., 2008). In this study, biologists mapped the proximity of human use 

areas to vegetation cover-type polygons that support these wildlife groups, and rated the 

risk of wildlife disturbance at sites where potential interactions were likely to occur at 

times of the year when each wildlife group would likely be most sensitive. The risk 

ratings ranged from low to very high, based on the type of activity, proximity, and level 

of sensitivity. The study does not account for all recreational use or all wildlife species, 

but serves to highlight the types of disturbances that are most likely to affect various 

wildlife groups, and where these effects are most likely to occur. 
54 

In general, the study indicated that recreational activity is most likely to affect 

shrubland birds, shrubland herptiles, grassland herptiles, and riparian dwellers. Vehicle 

traffic, particularly off-road traffic, damages habitat for these species groups, and offroad vehicle noise and activity during the breeding season can impair reproductive 

success for many birds. Road-related mortality can be significant for reptiles and 

amphibians generally, and for snakes in particular, because they frequently use roads to 

thermoregulate. Snakes are also at risk from intentional harassment or killing, or 

unintentional harm as a result of recreators chasing, capturing, or handling them. 

Illegal shooting was also identified as a risk to cliff dwellers. The Snake River 

Canyon is closed to all firearms between February 15 and August 31, but Idaho Power 

reports that recreational shooting continues to occur, despite informational signs 

informing visitors that it is not permitted. 

Idaho Power also identified special status species that could be affected by project 

operation (primarily flow fluctuations in the Swan Falls reservoir and along the Snake 

River downstream of the project), as well as by human activity. These wildlife species 

(table 9) are strongly associated with wetland cover types that occur within the 

fluctuation zone. 

Table 9. Special status species that could be affected by project operations (Source: 

Moser and Holthuijzen, 2008, as modified by staff). 

Species Primary Cover Type Association 

Trumpeter swan LS, LM, EHW 

Great egret LS, EHW, SSW, FW 

Wilson’s phalarope LS, EHW 

Brewer’s blackbird EHW, SSW, FW 

Spotted bat CTS, EHW, SSW, FW, SBW 

Yuma myotis CTS, EHW, SSW, FW, SBW 

Western pipistrelle CTS, EHW, SSW, FW, SBW 

Northern leopard frog EHW, SSW, LS 

Woodhouse’s toad EHW, SSW, LS 

Western toad EHW, SSW, FW, LS 

Common garter snake EHW, SSW, SBW, LS 

Notes: CTS – cliff/talus slope 

 EHW – emergent herbaceous wetland 

 FW – forested wetland 
55 

 LM – lotic (moving) water 

 LS – lentic (standing) water 

 SBW – shore and bottomland wetland 

 SSW – scrub-shrub wetland 

3.3.3.2 Environmental Effects 

Wildlife Habitat Protection and Enhancement Plan 

Idaho Power has identified several ways in which project operation and 

maintenance affect wildlife habitat in the project area. Idaho Power states that water 

level fluctuations both in the reservoir and downstream of the dam are minimal because 

the project is not operated as a load-following facility. It states that current and proposed 

operations are estimated to affect 2.0 acres of riparian habitat downstream of Swan 

Falls dam. 

Idaho Power notes that project operations and maintenance affect riparian habitat 

at Swan Falls Island, where construction of the new powerhouse in 1994 may have led to 

siltation and blockage of the culvert that once provided water to the channel around the 

island, reducing hydrologic support for 8.9 acres of scrub-shrub and emergent wetland 

that have developed there. Idaho Power states that at the lay-down yard adjacent to Swan 

Falls Island, where disposal of plant materials that are removed from the trash racks has 

spilled over into the riparian zone, the encroachment is smothering existing riparian 

vegetation and interfering with the processes of germination and growth. 

Additionally, Idaho Power notes that recreational activities at nine dispersed sites 

within the Swan Falls Project boundary have altered an estimated 3.72 acres of riparian 

habitat and 45.3 acres of upland habitat by removing and trampling vegetation, 

compacting soils, increasing erosion, and introducing litter. Idaho Power states that 

recreational activities serve as a vector for the spread of weeds and increase the risk of 

wildfire, and that in addition, traffic and noise associated with recreational activities 

cause disturbance to wildlife. Idaho Power also notes that illegal shooting in the area 

may also cause disturbance. For further discussion, see section 3.3.5, Recreation. 

To mitigate the effects of project operation on riparian and upland habitat, Idaho 

Power consulted with FWS, BLM, and Idaho DFG to develop a Wildlife Habitat 

Protection and Enhancement Plan. The plan includes: (1) protection and enhancement of 

2.7 miles of shoreline habitat to mitigate the effects of project operation on riparian 

habitat; (2) improvement of flows at Swan Falls Island to support 8.9 acres of riparian 

vegetation; (3) protection of riparian vegetation adjacent to the lay-down yard; and 

(4) protection and enhancement of 25.1 acres of riparian habitat and 45.3 acres of upland 

habitat to mitigate the effects of project-related recreation, including adverse effects on 
56 

wildlife. In the state of Idaho’s comments filed August 14, 2009, Idaho DFG stated its 

support for this proposal. 

With implementation of this plan, Idaho Power would establish desirable woody 

species (e.g., peachleaf willow, coyote willow, netleaf hackberry, skunkbush, and golden 

currant) in riparian areas along 2.7 miles of the Snake River shoreline that currently 

support little perennial vegetation or are dominated by invasive species. Planting would 

coincide with treatment of noxious exotic woody species, such as saltcedar. The areas 

targeted for riparian habitat enhancement are located within the project boundary along 

the eastern shoreline of the Swan Falls reservoir and along the eastern shoreline of the 

Snake River below the dam, including the slough at Swan Falls Island. 

To ensure the success of plantings at Swan Falls Island, hydrologic support would 

need to be restored. To this end, the Wildlife Habitat Protection and Enhancement Plan 

calls for excavation of about 1,000 cubic yards of material to create a connecting channel 

and replacement of the existing culverts to allow flow into the slough. Idaho Power 

would periodically monitor the effectiveness of this measure to ensure proper 

functioning, which is defined as the unimpeded flow of water to the side channel when 

flows in the Snake River exceed 6,220 cfs in July. 

To address the effects of lay-down yard encroachment on the riparian area, Idaho 

Power would remove existing desiccated plant materials from the embankment at the laydown yard, restore existing riparian vegetation, and install a barrier to prevent plant 

material from spilling over into riparian habitat in the future. 

To address effects on uplands affected by recreational use of the area, the Wildlife 

Habitat Protection and Enhancement Plan includes blocking and revegetating a total of 

8.4 acres of roadbeds and restoring 36.9 acres of other disturbed sites by planting native 

containerized shrub stock and seeding with native grasses. The plan specifies seed 

quality, planting rates, and the time of planting, and provides for weed control as well. 

The plan also includes an effectiveness monitoring protocol that Idaho Power would 

follow to evaluate planting success with provisions for consulting with the agencies 

10 years after implementation to determine whether any remedial actions are needed. 

Idaho Power would restrict motorized traffic to protect restored sites by 

strategically placing boulders, berms, fencing, and signage. Idaho Power would 

coordinate with state and federal law enforcement agencies to impose travel restrictions. 

The plan calls for establishing permanent reference photo locations to show 

representative views of restored areas and periodically re-photograph the sites to evaluate 

the success of enhancement efforts, in addition to measuring plant survival. The plan 

provides for regular reports to be filed with the Commission and provided to the 

resource agencies. 
57 

Our Analysis 

Our review of the C.J. Strike final EIS (FERC, 2002) indicates that C.J. Strike 

operations are the primary operational influence on riparian habitat along the shoreline 

upstream of the Swan Falls dam. Based on studies conducted in association with 

relicensing of the C.J. Strike Project, load following at C.J. Strike adversely affects 

170 acres of riparian habitat downstream of C.J. Strike dam, an area which includes the 

Swan Falls reservoir shoreline. Idaho Power is currently implementing a plan to protect 

and manage habitat for wildlife in the Bruneau Valley, which extends south from the 

Snake River just upstream of C.J. Strike dam, to mitigate these impacts. 

The Swan Falls Project is operated to reregulate flows from C.J. Strike. Daily 

river fluctuations below the dam comply with ramping rate restrictions of no more than 1 

foot per hour and 3 feet per day, with actual fluctuations being much smaller. In 2006, a 

high water year, the maximum water level fluctuation measured during a 1-day or 2-day 

period was less than 1.3 feet 90 percent of the time. During June through September, the 

maximum fluctuation was less than 1.1 feet 90 percent of the time. The following year, 

2007, was a low water year. The maximum water level fluctuation for the year during a 

1-day or 2-day period was less than 1.0 foot 90 percent of the time, and during the June 

through September period, was less than 0.68 foot 90 percent of the time. We anticipate 

that downstream water level fluctuations would be about the same under Idaho Power’s 

proposal as they are under current conditions. 

As discussed in section 3.3.3.1, Terrestrial Resources, Affected Environment, there 

are 2.89 acres of land within this fluctuation zone downstream of the dam, including 2.0 

acres mapped as riparian cover types. Emergent herbaceous wetland accounts for about 

0.76 acre, shore and bottomland wetland accounts for about 0.6 acre, and scrub-shrub 

wetland accounts for about 0.69 acre. Protection and enhancement of 2.7 miles of 

shoreline habitat, combined with improving flows at Swan Falls Island and controlling 

adverse effects on riparian habitat at the lay-down yard, would benefit riparian habitat in 

the project area. 

By improving existing riparian habitat conditions, implementation of the Wildlife 

Habitat Protection and Enhancement Plan would also improve conditions for numerous 

wildlife species in the project area that use riparian habitat. In the arid and semi-arid 

west, more wildlife species use riparian habitats than any other vegetation type 

(Kauffman et al., 2001; Knopf et al., 1988). Benefits of implementing the plan would 

include enhancement of wetter, cooler microclimates that support higher levels of 

primary productivity than surrounding, drier shrub and grassland types. Revegetation 

using native and other desirable shrubs and trees would increase species and structural 

diversity, which would in turn provide unique food resources, nesting opportunities, and 

hiding and thermal cover for wildlife. Revegetation would also improve the function of 

riparian areas as travel corridors that allow for daily movement, seasonal migration, and 

juvenile dispersal. 
58 

Several special status wildlife species that are strongly associated with emergent 

herbaceous wetland, shore and bottomland wetland, and scrub-shrub wetland would 

benefit from implementation of the plan; these species include trumpeter swan, great 

egret, Wilson’s phalarope, Brewer’s blackbird, northern leopard frog, Woodhouse’s toad, 

and common garter snake. The plan would also help to improve foraging opportunities 

for three special status bat species (spotted bat, Yuma myotis, and western pipestrelle). 

Implementation of other elements of the Wildlife Habitat Protection and 

Enhancement Plan, including blocking and revegetating 8.4 acres of roadbeds and 

restoring 36.9 acres of other disturbed sites by planting native containerized shrub stock 

and seeding with native grasses, as well as restricting motorized traffic to protect restored 

sites by strategically placing boulders, berms, fencing, and signage, would improve 

habitat conditions in project area uplands. In the intermountain west, shrub-steppe 

habitat supports at least 61 species of birds and small mammals that are entirely or almost 

entirely dependent on this increasingly fragmented ecosystem (Dobkin and Sauder, 

2004). Several of these are special status species that have been documented in the 

project area, including sage sparrow, Brewer’s sparrow, black-throated sparrow, sage 

thrasher, night snake, and longnose snake, as well as Woodhouse’s toad, which also uses 

riparian habitats. 

Provisions for monitoring as part of the Wildlife Habitat Protection and 

Enhancement Plan would ensure that Idaho Power would collect data needed to evaluate 

the success of the plan and to identify any modifications that may be needed to improve 

outcomes of the revegetation and traffic restriction measures. Provisions for reporting 

would allow stakeholders to participate in identifying such modifications, and may also 

identify opportunities for cooperative efforts. 

Several elements of Idaho Power’s other proposed protection, mitigation, and 

enhancement measures would also benefit riparian and upland habitat and the wildlife 

species that use them. We discuss these measures in the following section, Effects of the 

Recreation Management Plan. 

Effects of the Recreation Management Plan 

As noted above, recreational activities in the Swan Falls Project area have altered 

an estimated 3.72 acres of riparian habitat and 45.3 acres of upland habitat. Because of 

the interrelationship between Idaho Power’s proposed Wildlife Habitat and Enhancement 

Plan and its Recreation Management Plan in terms of effects on habitat and wildlife, we 

address the habitat-related components of the Recreation Management Plan here. 

As part of the draft Recreation Management Plan (see section 3.3.5, Recreation 

Resources), Idaho Power would maintain and improve the project’s five existing 

developed recreation sites. Under the draft Recreation Management Plan, Idaho Power 

would expand and improve two boat access sites: (1) at the Swan Falls reservoir boat 
59 

ramp, Idaho Power proposes to install a vault toilet, enlarge the parking area, designate a 

boat staging area, and widen and steepen the boat ramp; and (2) at Swan Falls 

downstream boat ramp, improvements would be similar but would also involve 

construction of a two-lane boat ramp. At Swan Falls Park, Idaho Power would repair the 

shoreline, add a new dock, and provide new picnic tables. 

Idaho Power also proposes to define and enhance six dispersed recreation sites, of 

which four sites are outside the current project boundary. Idaho Power proposes to 

modify the project boundary and include all six sites as project features. To help keep 

recreational usage contained to these sites, Idaho Power proposes to close the various 

braided roads to the sites, restrict additional recreation use by installing buffers, and 

designate a single maintained road for the sites. The Recreation Management Plan also 

contains Idaho Power’s proposed Interpretation and Education Plan, with provisions for 

educating the public on the Snake River Birds of Prey NCA and on native and non-native 

fish, including conservation of the white sturgeon. 

Our Analysis 

Expansion and improvement of the two boat ramp sites would not adversely affect 

riparian or upland habitat because work would occur in areas that have already been 

affected by recreational use of unauthorized roads, trails, and parking areas. 

Enhancement measures at Swan Falls Park would occur in areas that are already 

disturbed and would not convert any existing wildlife habitat. 

Project-related construction at the three above-mentioned recreation sites would 

have the potential to cause noise disturbance. Some activities associated with 

implementation of the Wildlife Habitat Protection and Enhancement Plan (e.g., use of 

heavy equipment to excavate a new connecting channel, replacement of existing culverts 

at Swan Falls Island, and construction of a barrier at the lay-down yard) would also 

increase noise levels. We anticipate that most wildlife species would avoid these areas 

during construction, and that effects would be localized, minor, and temporary. 

Based on Idaho Power’s wildlife risk analysis, four wildlife groups (shrubland 

birds, shrubland herptiles, grassland herptiles, and riparian dwellers) are most vulnerable 

to habitat damage and disturbance caused by dispersed recreational activities. 

For shrubland birds, the highest risk of disturbance occurs from April to July, 

when birds are nesting and raising young and recreation use is at a peak. While 

disturbance at this time of the year can impair breeding success, disturbance throughout 

the spring, summer, and fall appears to also contribute to the loss and fragmentation of 

shrubland habitat that supports shrublands birds, such as Brewer’s sparrow, sage sparrow, 

sage thrasher, and black-throated sparrow. 
60 

For shrubland and grassland herptiles (e.g., night snake, Woodhouse’s toad, and 

longnose snake), risks are highest from March through October, coinciding with the time 

of year amphibians and reptiles are most active and recreational use of roads is high. 

Road-related mortality of herptiles can be significant, and for snakes, in particular, 

because they frequently use roads to thermoregulate. 

The months of highest risk for all riparian dwellers (a group that includes bird, 

snake, and amphibian species) are May, June, and July. The Snake River Canyon is hot 

and dry during the summer; riparian areas attract people to water, shade, and the cooler 

microclimate when wildlife use of these areas is also high. Habitat damage and noise are 

the primary influences on breeding birds, while recreation traffic can cause mortality to 

amphibians moving across roads to access shoreline wetlands and riverine shallows. 

These four wildlife groups would benefit substantially from protection of existing 

habitat, restoration of habitat, closure of unauthorized and unnecessary roads and trails, 

and control of dispersed recreation. Public education about wildlife protection would 

also be beneficial, especially with regard to snakes. These measures could include 

signage explaining the importance of avoiding interactions with rattlesnakes, keeping 

pets on leashes, and not handling reptiles and amphibians. Idaho Power’s proposal, 

which includes finalization and implementation of the Interpretation and Education Plan 

as part of the Recreation Management Plan, would address these concerns. 

Noxious Weed Management Plan 

Although the fluctuation zone below Swan Falls dam is narrow, measuring about 

0.26 vertical foot in elevation and 1.3 feet laterally during the growing season, even small 

changes alter soil conditions along the shoreline and contribute to conditions that promote 

the establishment and spread of noxious weeds and invasive exotic plants. Project 

maintenance and management and project-related recreation also cause soil disturbance, 

and act as vectors for the spread of weeds. Noxious weed surveys conducted in the 

project area documented the occurrence of 12 noxious weed species within the project 

boundary. 

State law requires that Idaho landowners control noxious weeds on their property. 

To comply with this requirement and mitigate project effects on weed occurrence, Idaho 

Power consulted with FWS, BLM, and Idaho DFG to develop a Noxious Weed 

Management Plan (Vistine-Amdor et al., 2009). The plan is intended to control the 

introduction and spread of designated noxious weeds and monitor high priority areas for 

new infestations of noxious weeds. The plan would apply to all lands within the project 

boundary, including the transmission line. In the State of Idaho’s comments filed August 

14, 2009, Idaho DFG stated that it supports the plan. 

Idaho Power’s proposed Noxious Weed Management Plan would target the 12 

species known to occur within the project boundary that are designated as noxious weeds. 
61 

The weed control strategy would focus on creating and managing habitats to be resistant 

to invasive plants, while incorporating the use of mechanical, chemical, cultural, and biocontrol methods, as appropriate, to control weeds. The plan outlines a schedule for weed 

control activities and monitoring; identifies specific control methods to be considered; 

calls for regular updating of the target species list and new treatment measures that may 

become available; and provides for regular reports to FERC. Implementation of the 

Noxious Weed Management Plan would be coordinated with the Wildlife Habitat 

Protection and Enhancement Plan, the Special Status Plant Management Plan, and 

transmission line management. Idaho Power would also coordinate weed management 

efforts with private landowners and BLM.26 Idaho Power would work with county weed 

supervisors, resource management agencies, and other interested individuals or 

organizations to identify opportunities for cooperative projects, prioritize treatments, and 

organize efforts on all lands within the project boundary. 

Our Analysis 

As discussed in section 3.3.3.1, surveyors documented 983 populations of 14 

invasive species within the Swan Falls study area (Krichbaum, 2008a), including 12 that 

are designated as noxious weeds by the Idaho State Department of Agriculture 

(Krichbaum, 2008a). The surveys showed a very high diversity and abundance of weeds 

in survey units located along the shoreline and on islands. Krichbaum (2008a) suggests 

that weeds may be concentrated along the river/reservoir corridor because these areas 

include both upland and riparian habitats, with a range of soil moisture regimes and high 

exposure to a variety of disturbance factors, including recreation, flooding, grazing 

(where permitted on BLM or private lands), sediment deposition, and road construction. 

Based on these survey findings, we conclude that noxious weed control efforts would be 

most beneficial where they target recreational activities on project lands, but that several 

types of disturbance that are not project-related (e.g., grazing) would also need to be 

addressed, because they also occur on project lands. 

Implementation of Idaho Power’s proposed Noxious Weed Management Plan 

would provide an effective means of managing noxious weeds on project lands because it 

includes regular monitoring, a wide range of treatment options, follow-up surveys, and 

periodic updates to the list of target species. Although non-project-related activities 

would likely continue to influence weed distribution in the project area, implementation 

of cooperative efforts with other landowners would reduce the spread of weeds across 

ownership boundaries. Implementation of the plan would also augment measures 

included in the Wildlife Habitat Protection and Enhancement Plan by promoting native 

plant communities that provide higher quality habitat for wildlife than those dominated 

by invasive non-native species. 

 

26 In particular, Idaho Power must comply with the conditions of the BLM rightof-way grant (No. IDI-29012) regarding pesticide use. 
62 

As discussed above, altered soil conditions can contribute to the establishment and 

spread of weed populations. Idaho Power has restricted vehicle access to lands upstream 

of the reservoir boat ramp since 2007, and as part of the Recreation Management Plan, 

now proposes to restrict vehicle traffic to one maintained road downstream of the dam, as 

well as recontour and revegetate braided roads. Road closures and habitat restoration 

would help support native plant communities, and in combination with weed treatment, 

follow-up monitoring, and annual surveys outlined in the Noxious Weed Management 

Plan, would assist Idaho Power in controlling existing weed occurrences and minimizing 

the risk that new populations will establish in the project area. 

Special Status Plant Management Plan 

Special status plant surveys documented the occurrence of western germander and 

giant helleborine, two species that are strongly associated with riparian habitats, growing 

where they would be affected by flow fluctuations along the river downstream of Swan 

Falls dam, as well as ground disturbance resulting from dispersed recreation. Projectrelated recreation could also adversely affect three special status plants (Snake River 

milkvetch, desert pincushion, and white eatonella) that were documented in uplands 

within the proposed project boundary (see table 7). 

To mitigate project impacts on special status plants, Idaho Power consulted with 

FWS, BLM and Idaho DFG to develop a Special Status Plant Management Plan (Tyrer et 

al., 2009). In the state of Idaho’s comments filed August 14, 2009, Idaho DFG stated that 

it supports the plan. 

The Special Status Plant Management Plan includes measures to protect, monitor 

and manage rare plants within the project boundary. The primary elements of the plan 

include constructing fences or placing boulders to prevent access to special status plant 

populations; controlling noxious and undesirable plant species; planting native grasses 

and shrubs to rehabilitate disturbed uplands; protecting special status plants from grazing, 

where possible,27 adopting best management practices for road construction and 

maintenance that would minimize erosion, habitat loss and noxious weed spread; 

excluding the use of herbicides near special status plant populations; monitoring known 

populations to ensure habitat degradation does not occur; and clearance surveys before 

any ground-disturbing activities are implemented in areas that were not covered during 

previous survey efforts. The plan also addresses regular updates to the target species list 

and reports to be filed with the Commission, coordination with the Wildlife Habitat 

Protection and Enhancement Plan and the Noxious Weed Management Plan, and 

cooperative measures with state and federal agencies. 

 

27 The plan would cover all lands within the project boundary, including land that 

is administered by BLM, where grazing may be permitted. 
63 

Our Analysis 

Proposed operations would not substantially alter the existing pattern of reservoir 

fluctuations that results primarily from operation of the C.J. Strike Project, and would 

therefore not affect the 30 western germander populations or the one giant helleborine 

population growing in the study area upstream of the Swan Falls dam. As mentioned 

above, water surface fluctuations are estimated to affect 2.0 acres of riparian habitat 

downstream of the Swan Falls dam, and would have the potential to affect western 

germander populations growing within one or two height classes and within 1 or 2 feet of 

the river shoreline. The giant helleborine occurrence downstream of the dam is located 

farther above the OHWM (i.e., three height classes at its nearest point), but within about 

1.5 feet laterally, and could also be affected by current or proposed operations. 

The Special Status Plant Management Plan would not address any flow-related 

effects on western germander or giant helleborine. The abundance of western germander 

along the reservoir shoreline (30 populations) compared to the relatively small number of 

occurrences downstream of the dam (six populations) indicates that this species may 

prefer more stable hydrologic conditions than would occur along the Snake River 

shoreline under any operational scenario. For this reason, maintaining the current 

ramping rate restrictions would be important in providing continued support for 

these occurrences. 

In addition to evaluating the effects of project operation on special status plants, 

Idaho Power used GIS mapping and the results of the special status plant surveys to 

analyze the interactions between human activities and special status plant locations in the 

study area (Carpenter et al., 2008). Based on this analysis, there may be conflicts for 44 

populations of the 5 special status species (Snake River milkvetch, desert pincushion, 

white eatonella, giant helleborine, and western germander) that occur within the project 

boundary. In most cases (39), the risk of disturbance was rated as very low or low 

(Carpenter et al., 2008). Risks were rated as high for three populations of Snake River 

milkvetch and one population of western germander. Four Snake River milkvetch 

populations and two western germander populations could be affected by construction of 

proposed recreation enhancements. 

Idaho Power’s proposed Special Status Plant Management Plan would provide an 

effective means of protecting these species from recreational activity where they occur 

within the project boundary. Fencing or boulders would prevent impacts from off-road 

vehicles, pedestrian trampling, or grazing. Invasive plant control without the use of 

herbicides, together with upland habitat restoration using native plants, would discourage 

the establishment or spread of weed species that could outcompete special status plant 

populations. The results of clearance and monitoring surveys would provide the 

information that Idaho Power would need for planning and siting new recreation 

facilities, and for modifying the plan, as needed. Coordination with other management 

plans (e.g., for wildlife and noxious weeds) would ensure that rare plant occurrences are 
64 

protected to the extent possible during implementation of ground-disturbing activities; 

coordination with the Recreation Management Plan would provide additional protection. 

Idaho Power’s proposal to implement cooperative protection measures would offer 

a comprehensive approach to special status plant protection on land within the project 

boundary. Such an approach recognizes that different land owners within the project 

boundary may have different management responsibilities and priorities, but may share 

common goals for rare plant protection. 

Transmission Line Management 

The project transmission line, the Swan Falls Tap, extends approximately 1 mile 

from the Swan Falls powerhouse, up the canyon wall and across the benchlands to the 

Strike Junction-Caldwell transmission line, encompassing 6.07 acres within the 50-footwide right-of-way. It includes eight wooden H-frame power poles. Three are located 

below the canyon rim, one is at the canyon rim, and four are located on benchlands east 

of the Swan Falls Road. 

Maintenance activities include annual inspections, pole treatments on a 10-year 

cycle, and repair and replacement of structures and hardware as needed. Inspections and 

line patrols typically are conducted by one person in a truck or on an all-terrain vehicle, 

and take less than 1 day. Pole inspections and groundline treatments at 10-year intervals 

require climbing the poles to evaluate conditions; these activities are also completed 

within 1 day, with separate follow-up if equipment needs to be repaired or replaced. For 

this type of work, Idaho Power would typically use a line crew of four to six people. The 

types of trucks and cranes used would depend on the type of work that needs to be done; 

work could last from a day to a week. 

The Swan Falls Tap was designed to meet protective guidelines developed by the 

Avian Power Line Interactions Committee (APLIC, 1996) under the requirements of 

existing License Article 38, and no concerns about raptor electrocution or collision were 

identified during scoping. However, comments indicated a concern that ongoing 

maintenance activities could adversely affect four special status birds that nest in the 

benchlands (long-billed curlew, short-eared owl, Brewer’s sparrow, and sage sparrow), 

certain cliff-nesting raptors (e.g. prairie falcon), and tow wintering raptors (northern 

goshawk and bald eagle). By letter filed September 1, 2009, FWS commented that, 

although the bald eagle is no longer listed as threatened under the Endangered Species 

Act, the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act 

continue to provide protection for this species, and that National Bald Eagle Management 

Guidelines (FWS, 2007) have been developed to assist project proponents in avoiding 

violations of these laws. 

In its final license application, Idaho Power proposes to develop and implement a 

transmission line operation and maintenance plan to eliminate or minimize potential 
65 

impacts on botanical and wildlife resources as a result of major ground-disturbing 

activities along the Swan Falls Tap, in compliance with BLM right-of-way grant 

stipulations. Idaho Power indicated that it did not anticipate any need (absent 

catastrophic failure) to perform major repairs because the Swan Falls Tap is relatively 

new. In response to our AIR dated October 7, 2008, Idaho Power described specific 

management measures for the transmission line right-of-way that would be included in 

the Noxious Weed Management Plan, such as weed monitoring and treatment, erosion 

control, and special status plant protection, but did not address any measures that might 

be needed to protect wildlife during major repairs or routine maintenance activities. 

Our Analysis 

Idaho Power did not conduct field surveys to evaluate wildlife use of the Swan 

Falls Tap right-of-way, but the wildlife community would include most of the same 

species found elsewhere in project area uplands. Based on BLM and USGS surveys, the 

nearest known raptor nests are located 230 feet (prairie falcon pair), 1,312 feet (prairie 

falcon pair), and 1,640 feet (red-tailed hawk nest) from the right-of-way (Baczkowski and 

Carpenter, 2008). There is typically one raven nest located about 328 feet from the rightof-way each year. 

Four special-status bird species (long-billed curlew, short-eared owl, Brewer’s 

sparrow, and sage sparrow) nest on benchlands. We refer to these birds collectively as 

benchland nesters. Nesting surveys for these species have not been conducted, but it is 

likely that few nests would have the potential to be affected by transmission line 

maintenance activities because there are only four poles on the benchlands above the 

canyon rim. However, if nests were located near the poles, disturbance between April 

and July could impair reproductive success by keeping adults from the nest, exposing 

eggs or young to weather and predation. Disturbance could be avoided by scheduling 

major (i.e., lasting more than a day) non-emergency work to occur between August 

and March. 

Idaho Power anticipates that transmission line maintenance activities would have 

the potential to affect only one cliff-nesting raptor species—the prairie falcon 

(Baczkowski and Carpenter, 2008). One or two nesting pairs would be disturbed by any 

work at the pole located on the canyon rim if such work occurred between March and 

June. Idaho Power notes that birds in this part of the canyon are fairly tolerant of 

disturbance, even tolerating noise associated with blasting (Holthuijzen et al., 1990). The 

risk of disturbance could be minimized by scheduling major non-emergency work 

between July and February. 

Two raptor species—bald eagles and goshawks—may use trees in Swan Falls Park 

during the winter for night roosting or day perching. Two poles are situated upslope of 

these trees, which would increase the potential for disturbance to these species between 

November and March. However, it is unlikely that work would occur at night, and work 
66 

lasting a few hours during one day each year (or several days if either or both poles 

require replacement) would have negligible impacts because perching birds would move 

to other suitable perch trees in the vicinity. 

Under current conditions, there are no timing restrictions on transmission line 

maintenance activities. Idaho Power’s proposed Noxious Weed Management Plan 

provides for timing restrictions on herbicide applications within the right-of-way in the 

future, if needed. However, we conclude that timing restrictions on maintenance 

activities would also be needed to minimize the risk of disturbing benchland nesters and 

cliff-nesting raptors. 

As described above, the Noxious Weed Management Plan provides for weed 

monitoring and treatment, erosion control, and special status plant protection throughout 

the project area, including the Swan Falls Tap. Development of a separate transmission 

line operation and maintenance plan, as Idaho Power proposes, would not be necessary to 

protect soil or botanical resources that occur within the transmission line right-of-way. 

However, the Noxious Weed Management Plan does not address potential effects of 

transmission line operation and maintenance on wildlife. A separate measure could be 

implemented, however, to address potential noise disturbance without duplicating 

previous planning efforts or other management programs. Such a measure would provide 

a mechanism for Idaho Power to consider the effects of various maintenance activities on 

benchland nesters and cliff-nesting raptors, and implement timing restrictions, as needed, 

for major repairs, routine maintenance, or both. 

Raptors within the National Conservation Area 

As mentioned in section 3.3.3.1, Terrestrial Resources, Affected Environment, the 

Snake River Birds of Prey NCA supports one of the highest densities of non-colonial 

nesting raptors in the world. Comments received during scoping indicated a concern that 

project operations and project-related activities could affect raptor populations within the 

NCA. In reviewing the licensing record for the Swan Falls Project, it does not appear 

that this concern was specifically identified during the consultation process, and Idaho 

Power does not propose any protection, mitigation, and enhancement measures 

addressing raptor populations within the NCA. 

Our Analysis 

For raptors, the importance of the NCA is due primarily to an abundance of cliff 

nesting sites in proximity to an abundance of prey. The principal prey species are blacktailed jackrabbits and Piute ground squirrels. Black-tailed jackrabbits, which occur in 

shrublands throughout the NCA, rarely use grasslands without a shrub component, owing 

to their reliance on shrubs for food and cover. Piute ground squirrels do use annual 

grasslands, but non-native annual grasses are less drought tolerant than native species, 

and therefore may not provide a stable food resource. Piute ground squirrels are found in 
67 

highest numbers on the benchlands north of the Snake River in the NCA; they are rarely 

found in the canyon, and do not occur southwest of the river in the vicinity of the NCA. 

Idaho Power used unpublished data from BLM and USGS surveys conducted 

between 1990 and 1994 to calculate nesting densities for golden eagles, red-tailed hawks, 

ferruginous hawks, and prairie falcons, and additional data on prairie falcons that was 

collected during surveys in 2002. The survey units used in the analysis covered habitat 

(including benchlands) within 1.2 miles of the Snake River from RM 442, near Walters 

Ferry, to RM 478, about 20 miles upstream of Swan Falls dam. Idaho Power’s analysis 

showed that territory densities were highest in the 6.2-mile survey segment that includes 

Swan Falls dam, with an average of 50.4 territories. The second highest densities (an 

average of 41.6 territories) occur in the 6.2-mile segment just upstream of the dam, along 

the Swan Falls reservoir. Results were similar for ravens, which share nesting and prey 

preferences with many raptor species. 

Data presented in the NCA Resource Management Plan (BLM, 2008) include the 

results of prairie falcon surveys over a wider span of years (1976 through 2002) and a 

longer stretch of the river (from Walters Ferry upstream to RM 530, near Hammett); 

these data also show the highest densities of prairie falcons centering on the survey units 

that encompass the Swan Falls Project area. These survey units contain the highest cliffs, 

and provide optimal habitat. They are almost fully saturated every year, while the 

number of pairs in less suitable survey units to the west and east fluctuates from year to 

year as the prairie falcon population decreases and increases (Kochert and Steenhof, 

2004, as cited in BLM, 2008). 

Based on these evaluations, we find that continued project operations are not 

adversely affecting raptor populations in the NCA. Project operations do not affect cliff 

nesting or benchland foraging habitat. However, as discussed above, project operations 

do influence a narrow band of riparian and upland habitat along the Snake River. To 

address effects on these cover types, Idaho Power’s proposed Wildlife Habitat Protection 

and Enhancement Plan calls for restoration of 2.7 miles of riparian habitat along the 

Snake River shoreline that is currently poorly vegetated or dominated by weeds. Because 

the plan includes planting of native and other desirable perennial species that may 

eventually provide perch and roost sites for raptors and hiding cover and forage for small 

mammals, reptiles, amphibians, and songbirds that contribute to their prey base, 

implementation of the plan could provide a long-term benefit to raptors. 

Project-related maintenance activities would have the potential to cause noise 

disturbance in the vicinity of the dam and powerhouse. Bald eagles and goshawks are 

thought to perch near the dam in the winter, but no raptors are known to nest in the 

immediate area. Effects of noise would likely be minor and temporary. 
68 

As discussed above, maintenance of the Swan Falls Tap would have the potential 

to cause noise disturbance to one or two pairs of prairie falcons, if conducted during the 

breeding season. Foraging raptors would likely avoid the transmission line route for as 

much as a day at a time during annual and 10-year inspections, and for longer periods 

(i.e., up to a week) during major maintenance projects. However, the transmission line 

covers a relatively small portion (i.e., less than 6 acres) of the benchland habitat available 

for foraging, and any effects of maintenance activities on raptors are expected to be shortterm and minor. 

Project-related recreation activities would have a higher potential than 

transmission line maintenance to affect raptors, primarily through the activities’ effects 

on wildlife species that comprise the raptor prey base. Project-related recreation is 

estimated to affect approximately 3.72 acres of riparian habitat and 45.3 acres of uplands 

of project lands within the Snake River Canyon. The effects of dispersed recreation 

include erosion of upland soils, compaction of soils, trampling of vegetation, loss of trees 

to firewood collection or other camp uses, littering, introduction and spread of noxious 

weeds, and an increased risk of fire. Habitat along the river may be less important for 

raptors than cliffs (which support most nesting) and benchlands (which support the 

highest abundance of key prey species), but Idaho Power reports that the project area 

does support raptor nests, and the mix of cover types along the river supports a variety of 

birds, small mammals, reptiles and amphibians that would add to the diet of 

many raptors. 

Implementation of Idaho Power’s proposed Wildlife Habitat Protection and 

Enhancement Plan would help minimize the effects of dispersed recreation use on raptors 

by addressing impacts on habitat for their prey. With the plan in place, Idaho Power 

would limit and define some recreation sites, close unnecessary roads, control noxious 

weeds, and protect and enhance native plant communities on 25.1 acres of riparian 

habitat and 45.3 acres of uplands. 

The Wildlife Habitat Protection and Enhancement Plan does not address noise 

disturbance to raptors and other wildlife. As discussed above, the results of several years 

of surveys within the NCA show that nesting raptor densities are higher in the vicinity of 

the project than anywhere else in the NCA, suggesting that noise disturbance is not 

adversely affecting raptors, and noise disturbance is not identified as a key issue in the 

NCA Resource Management Plan (BLM, 2008). However, illegal shooting results in 

reverberation of loud and unpredictable noises, which have the potential to impair raptor 

productivity. The NCA Resource Management Plan (BLM, 2008) provides for a yearround target practice closure for shooting rifles and pistols within 0.5 mile of the Snake 

River downstream from Grand View (RM 487), and a closure of the same area to all 

firearms from mid-February through August. Idaho Power has installed “no shooting” 

signs at the boat dock and near the restrooms adjacent to the main access road. Inclusion 

of Idaho Power’s proposed interpretive signage (described in section 3.3.5, Recreation) 
69 

focusing on the importance of birds of prey would further educate visitors and could help 

to reduce illegal shooting. 

Deer Flat National Wildlife Refuge Islands 

During scoping, FWS indicated a concern that operation of the Swan Falls Project 

adversely affects terrestrial resources associated with the Refuge. As mentioned in 

section 3.3.3.1, the Refuge includes 101 islands distributed along 113 miles of the Snake 

River from approximately the Guffey Bridge downstream to Farewell Bend. Two of the 

Refuge islands (Rail and Sign islands) are located within the terrestrial resource study 

area, but none are located within the existing or proposed Swan Falls Project boundary. 

Rail and Sign islands are located approximately 10 river miles downstream of Swan 

Falls dam. 

In its June 4, 2009, filing in response to our AIR, Idaho Power filed copies of three 

studies that were conducted along the Snake River downstream of Swan Falls dam in the 

1990s, as authorized by Public Law 100-216. These studies (Johnson et al., 1992; 

Johnson et al., 1995; Dixon and Johnson, 1999) describe changes in riparian vegetation 

over time and evaluate the effects of potential flow reductions on riparian vegetation. In 

comments filed September 29, 2008, Idaho Power stated that low flows in the Snake 

River are primarily the result of U.S. Bureau of Reclamation (Reclamation) irrigation 

storage reservoirs upstream of Swan Falls dam. Idaho Power also indicated that the 

recent drought has played a role in flows that would affect Refuge islands. 

In its August 12, 2009, filing responding to the Commission’s Ready for 

Environmental Analysis (REA) notice, FWS recommends that the Commission require 

Idaho Power to mitigate effects on Refuge islands that are affected by low flows in the 

Snake River, and provided copies of three additional studies in support of the 

recommendation. The Swan Falls Instream Flow Study (Anglin et al., 1992) focused on 

resident fish habitat, while two peer-reviewed papers (Zoellick et al., 2004 and Zoellick 

et al., 2005) addressed the effects of flows on island-nesting birds in general and 

waterfowl in particular. The documents describe how the Snake River island portion of 

the Refuge is affected by low flows, which FWS believes are partially caused by Swan 

Falls Project operation. 

Our Analysis 

Riverine islands are important elements of the landscape for many bird species, 

primarily because they offer security from terrestrial predators. Geese, ducks, terns, and 

other ground-nesting waterbirds may reach their highest densities on islands (Lokemoen 

and Woodward, 1992). Tree-nesting waterbirds also reach high densities on islands, 

where nests can be located within clear view of foraging areas in the water. 
70 

Review of aerial photographs covering four periods (1938–1939, 1957, 1969, and 

1987) show that coverage of riparian woodland, island riparian, and total riparian 

vegetation, as well as the area of islands in the Snake River between Swan Falls dam and 

the Idaho-Oregon border, has increased over time, and that the greatest changes occurred 

between 1969 and 1987 (Johnson et al., 1992; Johnson et al., 1995; Dixon and 

Johnson, 1999). 

Johnson et al. (1992) integrated the results of the time-series comparison with field 

surveys, geomorphological assessment, and mapping and modeling efforts to predict 

changes in riparian vegetation that would be likely to occur as a result of further flow 

reductions (i.e., those to be implemented as a result of the Swan Falls Agreement). The 

authors found that shallow areas near islands would be most sensitive to changes in flow. 

At these points, the expansion of riparian vegetation into the existing wetted channel 

could greatly reduce the channel width, or span the distance between the shoreline and 

the islands. 

These findings suggest that with low flows, riparian encroachment over time could 

strongly affect the degree of isolation of riverine islands from adjacent shorelines. Flow 

volumes and flow velocities have the potential to directly affect the degree of isolation as 

well. As flow volumes and velocities decrease, swimming becomes easier for 

mammalian predators, and predation rates on nesting birds may increase. 

Zoellick et al. (2004) studied island isolation and nest predation on 30 Snake River 

islands from 1990 to 1992, including several that are part of the Refuge. The study reach 

began at the Swan Falls dam and extended almost 40 miles downstream. The authors 

calculated island isolation at flows ranging from 3,900 cfs (the current minimum instream 

flow requirement for this reach of the Snake River during the October 1 to March 31 

irrigation season) to about 12,000 cfs. Based on these calculations, the authors concluded 

that flows of 3,900 cfs or less during the breeding season would result in very little 

isolation. Isolation would be expected to increase rapidly at flows of about 8,900 cfs or 

more, and flows of about 12,000 cfs or more would discourage most predators. 

In a related study, Zoellick et al. (2005) focused on the distribution and 

composition of mammalian predators identified as visitors to the 30 Snake River islands. 

The authors concluded that at flows of approximately 6,500 cfs, visitation rates of 

predators were 2 to 4 times higher at mainland sites adjacent to the islands, and that flows 

below 6,500 cfs could substantially increase the risk of predation by four of the most 

common predators—coyote, raccoon, red fox, and striped skunk. Both studies (Zoellick, 

et al., 2004 and Zoellick, et al., 2005) confirm the benefits of island isolation to groundnesting birds. 

We find that higher flows, if they were to be made available from hydropower or 

water storage reservoirs upstream of Swan Fall Project, would benefit ground-nesting 
71 

birds on Refuge islands by reducing the risk of mammalian predation. However, it is 

unlikely the Swan Falls Project could be operated to either positively or negatively affect 

Refuge islands, without modification of the operation of Reclamation storage reservoirs 

in the upper Snake River Basin. The total storage capacity of the Swan Falls reservoir is 

7,425 acre-feet, and the useable storage capacity is 680 acre-feet. By comparison, 

Reclamation reservoirs in the upper Snake River Basin have a total storage capacity of 

4,045,695 acre-feet (Reclamation, 2009). The capacity of the C.J. Strike reservoir is 

220,000 acre-feet. Swan Falls is operated to reregulate flows released from C.J. Strike, 

and outflow essentially reflects inflow. With limited ability to store water, there is little 

opportunity for Swan Falls Project operation to modify baseflows, given the current 

availability of water, or to modify the magnitude, frequency, or duration of peak flows. 

3.3.3.3 Cumulative Effects 

During scoping, our review of the license application, technical appendices, and 

agency comments, as well as our observations during the site visit, indicated that Swan 

Falls Project operation and recreation near the project could contribute to cumulative 

adverse effects on riparian habitat that result from operation of other hydropower projects 

between Shoshone Falls and Brownlee reservoir. Grazing and water withdrawals for 

irrigation have also dramatically affected riparian habitat along the Snake River since the 

1800s, when homesteaders began to settle the region. Together, these factors have 

reduced the extent and quality of riparian habitat in a region where climate and soils 

already limit the distribution of this important natural resource. While riparian vegetation 

accounts for 9.6 percent of the area within the Swan Falls Project boundary, it occupies 

only 1.1 percent of the mid-Snake subbasin (Ecovista and Idaho DFG, 2004). 

In the future, population growth is likely to increase the competition for water 

resources and bring more visitors to recreation sites within the Swan Falls Project area. 

BLM reports that Ada and Canyon county populations grew about 46 percent between 

1990 and 2000, and that southwest Ada County is projected to grow by another 15 to 21 

percent by 2025 (BLM, 2008). 

Analysis of Swan Falls Project operations indicates that because of limited storage 

capacity and typically narrow stage fluctuations downstream of the dam, the project’s 

contribution to cumulative adverse effects is relatively small; river fluctuations 

downstream of the dam affect about 2.0 acres of riparian vegetation. Dispersed 

recreational activities have damaged an additional 3.72 acres of riparian habitat. With 

implementation of its proposed Wildlife Habitat Protection and Enhancement plan, Idaho 

Power would protect, enhance, or restore 2.7 miles of riparian vegetation along the Snake 

River shoreline, improve hydrologic support for side channel flows at Swan Falls Island, 

protect riparian vegetation adjacent to the lay-down yard, and protect and enhance a total 

of 25.1 acres of riparian habitat affected by recreational use. Idaho Power’s proposed 

Noxious Weed Management Plan would also enhance riparian habitat quality, and 

implementation of the draft Recreation Management Plan would provide for improved 

management of dispersed recreation along the river. These measures would complement 
72 

the positive effects of several actions that are outlined in the NCA Resource Management 

Plan (BLM, 2008). These actions include completion of motorized vehicle route 

designations for recreation, aggressive weed suppression, and elimination of public land 

grazing except for fuel and weed management purposes. Overall, Idaho Power’s 

proposals would contribute to cumulative benefits to riparian habitat within the midSnake River Basin, and especially within the NCA. 

3.3.4 Threatened and Endangered Species 

3.3.4.1 Affected Environment 

Aquatic Species 

In a letter filed with the Commission on September 1, 2009, FWS indicated that 

the Snake River physa (Haitia [Physa] natricina), a federally listed endangered species of 

snail, occurs in the project area. 

The Snake River physa snail is a freshwater mollusk found in the middle Snake 

River of southern Idaho. The physa is classified under the family Physidae and can reach 

a maximum length of about 6.5 millimeters. While much information exists on the 

family Physidae, very little is known about the biology or ecology of this species. It is 

believed to be confined to the mainstem Snake River, inhabiting areas with rocky or 

boulder substrates in relatively deep, fast-moving water, with good water quality (FWS, 

2005). It is not known to occur in slow-water or reservoir habitats (Taylor, 1988, 1982 

and Frest et al., 1991, as cited by FWS, 2005). The recovery area for the species extends 

from RM 553 to RM 675 (FWS, 1995). 

The Snake River physa is rare, with fewer than 50 total individuals having been 

collected (FWS, 2005). Taylor and Bowler (Taylor, 1988, as cited by FWS, 2005) 

collected the most recently confirmed live specimens of this snail between 1959 and 1987 

in the area between the Malad River’s confluence with the Snake River (RM 571) and 

Grand View (RM 487). However, more recent surveys conducted in 2003 at several of 

the same sites failed to locate either living specimens or empty shells (Frest and 

Johannes, 2004, as cited from FWS, 2005). The more recent collection of fresh shells 

from the reach between Minidoka dam (RM 673.5) and Milner pool (RM 666) 

(approximately 215 miles upstream of the Swan Falls Project dam) between 1987 and 

1997, as well as the lack of specimens from other formerly inhabited reaches, suggest that 

the Minidoka reach may contain one of the few remaining colonies of the species 

(FWS, 2005). 

Terrestrial Species 

Information filed by FWS on September 1, 2009, lists no threatened, endangered, 

proposed, or candidate terrestrial plant or wildlife species in the Swan Falls Project area. 

No additional species or critical habitat were identified during special status plant surveys 

or a review of scientific literature regarding plants and wildlife in the project area. One 
73 

wildlife species that winters in the project area—the bald eagle—was removed from the 

threatened and endangered species list effective August 8, 2007, but receives continued 

protection under the Bald and Golden Eagle Protection Act and the Migratory Bird 

Treaty Act. 

3.3.4.2 Environmental Effects 

Aquatic Species 

Snake River Physa Snail 

Idaho Power did not propose any specific measures in its license application to 

protect listed aquatic species. 

Our Analysis 

Operation of the Swan Falls Project has the potential to affect Snake River physa 

by causing water level fluctuations in Swan Falls reservoir and in the free-flowing reach 

downstream of the project. The available storage in Swan Falls reservoir is used to 

reregulate inflows resulting from operation of the upstream C.J. Strike Project, but can 

also be used to meet short-term, unexpected peak load requirements. The Swan Falls 

Project is operated to comply with ramping rate restrictions of no more than 1 foot per 

hour and 3 feet per day, measured at the gage approximately 1 mile downstream of the 

project. Normal maximum operating headwater is 2,314 feet msl, and minimum 

operating headwater is 2,310 feet msl. 

Under the current license, the project is required to maintain instantaneous 

minimum flows downstream of Swan Falls dam of no less than 5,000 cfs during the 

irrigation season (April 1 to September 30) and no less than 4,000 cfs outside the 

irrigation season (October 1 to March 31). If the average daily inflow is less than the 

specified minimums, the license provides that the plant discharge must be equal to the 

average inflow. 

Idaho Power proposes to operate the project to provide an instantaneous minimum 

flow of 3,900 cfs downstream of the dam from April 1 to October 31 each year, and 

5,600 cfs from November 1 to March 31, to be consistent with flows specified under the 

Swan Falls Agreement and to improve reregulation of peaking outflows from the 

upstream C.J. Strike Project. Idaho Power reports that the proposed minimum flows may 

result in slightly greater fluctuation of water levels in Swan Falls reservoir, but would 

reduce daily fluctuation of water levels downstream of the project, compared to current 

conditions. Because the Snake River physa is not known to occur in reservoir 

environments, the increased fluctuation in reservoir levels would likely not have any 

effect on the species. The tailwater reach provides habitat that is more suitable for the 

Snake River physa; however, the risk of stranding and dessication from changes in water 

levels would continue to be very low due to the species’ preference for areas of deep 

water and high water velocity outside of the fluctuation zone. 
74 

Idaho Power’s proposal to continue to remove aquatic vegetation that accumulates 

on the project’s trash racks would benefit habitat conditions for Snake River physa by 

removing nutrients and improving water quality. For these reasons, we conclude that the 

proposed project would not be likely to adversely affect the Snake River physa. 

Terrestrial Species 

As mentioned above, no federally listed or proposed terrestrial plant or wildlife 

species are known to occur in the project area. Idaho Power’s proposed Special Status 

Plant Management Plan includes regular updates to the list of target species, so that any 

plants that may be proposed or listed in the future would be protected under the plan. 

3.3.5 Recreation Resources 

3.3.5.1 Affected Environment 

The existing project boundary includes about 12 miles of the Snake River. The 

upstream project boundary extends upstream from the dam to the point where the 

reservoir transitions to a free-flowing river at RM 469.4; the downstream boundary 

extends 2,000 feet downstream of the dam to encompass a short reach of the tailwater 

(RM 457.3). 

Regional Recreation Opportunities 

The Swan Falls Project is located about 35 miles southwest of Boise, Idaho, on the 

Snake River in Ada and Owyhee counties. The Snake River is the border between the 

two counties, with Ada County located northeast of the river and Owyhee County located 

southwest of the river. Canyon County borders Ada County about 10 miles downstream 

of Swan Falls dam. 

There are two federally managed recreational resources that provide recreational 

opportunities along the Snake River in the area of the Swan Falls Project: the Deer Flat 

National Wildlife Refuge and the Snake River Birds of Prey NCA. FWS manages the 

Deer Flat National Wildlife Refuge, one of the oldest refuges in the National Wildlife 

Refuge System, located downstream and north of the project near Nampa, Idaho. Its 

recreational opportunities include a visitor center, wildlife watching and photography, 

hunting, fishing, environmental education, and self-guided river and lake tours. As noted 

in section 3.3.3.1, Terrestrial Resources, the Snake River Islands sector of the refuge 

contains about 800 acres on 101 islands; the two refuge islands located closest to the 

Swan Falls Project, Rail and Sign islands, are located about 10 miles downstream of the 

dam, outside of the existing and proposed project boundaries. 

The BLM’s Lower Snake River District manages the Snake River Birds of Prey 

NCA, which is located within and around the existing and proposed Swan Falls Project 

boundaries. The NCA extends along 81 river miles and encompasses 485,000 acres of 

public land, of which 529 acres are located within the current project boundary. Of the 

485,000 acres, 420,000 are considered prey habitat and 65,000 are considered habitat for 
75 

nesting birds. BLM manages a developed recreation site (Dedication Point) on the 

canyon rim about 2 miles north of the dam, offering visitors interpretive displays, 

graveled trails, benches, garbage cans, a covered small group kiosk, two vault toilets, and 

a parking area. The parking area is approximately 0.5 mile from the rim overlook where 

visitors can view the Snake River Canyon corridor and see birds of prey. 

The project’s only access road ends about 2 to 3 miles downstream of the dam at 

the NCA boundary. The site has a vault toilet and is the BLM trailhead for the Halverson 

Bar and Lake Trail leading to Halverson Lake and Canyon County’s Celebration Park. 

Trail users, including hikers, horseback riders, and mountain bikers, can cross Guffey 

Bridge and return to the dam on the opposite side of the river. Celebration Park is located 

on the Snake River at the western boundary of the NCA about 10 miles downstream of 

Swan Falls dam. Visitors are able to enjoy the high desert flora, scenic land features, and 

unique tribal art dating to 12,000 years ago. Celebration Park was established as Idaho’s 

only archaeological park in 1989. Since then, the park has been the recipient of several 

awards, including a 1997 Orchid Award from the Idaho Historic Preservation Council in 

Recognition of Superlative Achievement in Preserving Idaho’s Heritage, and Idaho 

Governor Dirk Kempthorne’s 2002 Take Pride in Idaho Award. Recreational activities 

offered at the park include hiking, fishing, boating, picnicking, camping, horseback riding 

trails, bird watching, ongoing interpretive park programs, and student field trips. 

Reservations are available for large group gatherings and tours. Facilities include a 

visitor center, restrooms, water, boat ramp, car and boat parking, and picnic tables 

(Canyon County, Idaho, 2009). 

Another activity available nearby are birding tours offered by Birds of Prey 

Expeditions, run by a private outfitter. From February through November, the outfitter 

conducts reservation-only boat tours of the Snake River upstream of Swan Falls dam, 

during which nesting areas are identified and the history of the area is described. 

In terms of regional recreational management goals, Recreation Next, Idaho’s 

2006–2010 Statewide Comprehensive Outdoor Recreation Plan (SCORP)28 (Idaho DPR, 

2006) identified seven goals and objectives for local, state, and federal outdoor recreation 

providers in Idaho. The seven goals and objectives are as follows: 

1. Provide enhanced outdoor recreation facilities and opportunities through 

funding that aligns with demand. 

2. Assure that the public has the best possible access to public lands for outdoor 

recreation. 

3. Recognize that water is an increasingly precious resource. 

 

28 This SCORP also goes by the title Statewide Comprehensive Outdoor 

Recreation and Tourism Plan (SCORTP). For consistency through this document, we 

will use SCORP to refer to this plan. 
76 

4. Develop a unified strategy for delivering outdoor recreation education to the 

public. 

5. Minimize the impact of invasive species. 

6. Encourage healthy living through outdoor recreation. 

7. Recognize the importance of transportation in planning projects. 

The SCORP provides an integrated assessment of recreation and tourism for the 

state and, at the policy level, a plan outlining goals and strategies to guide the 

coordination of efforts to provide and market sustainable, high-quality recreation and 

tourism opportunities in Idaho. The agency partners29 that developed the plan state that 

the plan was based on the best available scientific data and the ongoing experiences of 

the partners (Idaho DPR, 2006). 

Developed Project Recreational Opportunities 

Idaho Power owns and maintains all of the developed recreational facilities within 

the project boundary. Opportunities include boating access, impromptu or dispersed 

camping, picnicking, day use, visiting the museum, and viewing interpretive signs 

describing natural and historical features (see figure 3). Idaho Power does not charge 

user fees at any of its project facilities. Details of each existing facility and its respective 

opportunities are discussed below. 

• Swan Falls Park—Located along the northeast bank of the reservoir just 

upstream of the dam, this day-use park offers amenities such as full restrooms, 

benches, picnic tables, an interpretive display, and day-use parking. The park 

grass is maintained and large trees provide shade cover. The day-use park 

offers barrier-free access at most sites within the park. 

• Swan Falls reservoir boat ramp—Located on the northeast bank of the 

reservoir about 0.25 mile upstream of the dam, this one-lane boat launch with 

mooring docks offers amenities such as a portable toilet located in the parking 

area. In 2003, Idaho Power installed a second mooring dock upstream of this 

boat launch to accommodate increased demand and provide daily moorage of 

outfitters’ boats from April through June each year. 

 

29 Task Force partners include BLM, Reclamation, U.S. Forest Service, National 

Park Service, Idaho Association of Counties, Association of Idaho Cities, Idaho 

RV/Campground Owners Association, Idaho Department of Commerce and Labor, Idaho 

DFG, Idaho DPR, Idaho Department of Transportation, Idaho Department of Water 

Resources, Idaho Department of Health and Welfare, Idaho State Historical Society, 

Idaho Foundation for Parks & Lands, Idaho Outfitters and Guides Association, Idaho 

Recreation and Park Association, Idaho Recreation and Tourism Initiative, and Idaho 

Commission on the Arts. 
77 

• Swan Falls downstream boat launch—Located on the northeast bank of the 

tailwater area just downstream of Swan Falls dam is a gravel boat launch that 

provides access to a free-flowing segment of the Snake River. Amenities 

include parking, a portable toilet, and an air compressor, which was installed to 

assist rafters at this location. 

• Canoe portage trail—Located on the southwest bank adjacent to the dam, the 

portage trail includes a sign upstream of the dam to notify boaters of the trail’s 

location. The effective length of the portage varies with flows. When there is 

no spill, people portaging around the dam walk approximately 1,100 feet 

downstream to a safe launch point. When there is spill, portagers could walk 

up to about 2,500 feet downstream to launch. 

• Swan Falls powerhouse museum—Located within the converted old 

powerhouse, the museum contains a turbine/generator display and offers 

interpretive displays on the history of Idaho Power and the Swan Falls Project. 

Because of national security concerns, current visiting days and hours are 

restricted to Tuesday and Wednesday from 10:00 a.m. to 1:00 p.m. Tour 

groups must provide a list of the names and addresses of all adults on the tour 

at least 48 hours in advance. 

Undeveloped Dispersed Recreation Sites 

Public use of undeveloped dispersed recreation sites consists primarily of 

individuals who access the shoreline for fishing, dog walking, lounging, and bird 

watching. Idaho Power identified 26 undeveloped dispersed recreation sites within or 

outside the Swan Falls Project boundary, all of which are accessed via the project’s 

access road. Most of the dispersed recreation sites are impromptu and made by the public 

without management guidance. These existing sites typically incorporate almost all 

available flat areas along the northeast shoreline of the reservoir for about 0.25 mile 

upstream of the dam and the northeast shoreline of the river for about 2 to 3 miles 

downstream of the dam, and provide vehicle access to the shorelines as well. The typical 

dispersed site also has reasonably clear site boundaries and can be accessed by a vehicle 

from more than one primary or secondary road, which contributes greatly to site size and 

impact on environmental resources. Most sites have a fire ring, or fire scar, and trash 

present. Vehicle and human impact within the Swan Falls Project boundary is damaging 

other natural and cultural resources and the affected areas are expanding. 
78 

Figure 3. Recreational opportunities in the area of the Swan Falls Project (Source: 

Idaho Power, 2008a). 
79 

Recreation Use within the Swan Falls Project Area 

Based on the latest FERC Form 80 filed with the Commission on August 1, 2003, 

the Swan Falls Project had a total of about 21,534 visitors during the 2001 calendar 

year.30 Table 10 summarizes important information from the Form 80 report. 

Table 10. Summary of the Form 80 report for the Swan Falls Project in 2001 

(Source: Idaho Power, 2003). 

Type of Recreation Resource Number Total Acres Level of Usea

Access areas 2 -- Low 

Boat ramps 1 -- Low 

Boat launching lanes 1 -- Low 

White water boating 1 -- Low 

Canoe portage 1 0.1 Low 

Parks 1 0.5 Low 

Picnic areas 1 0.5 Low 

Interpretive displays 3 -- Low a

 The level of use is the annual average percentage of actual use of a particular facility 

compared to its use at full capacity. Low use of the facility is equal to or less than 40 

percent of its full capacity, medium use is between 40 and 60 percent of its full 

capacity, and high use is 60 percent or more of its full capacity. 

Idaho Power has conducted four recreational-use studies from 1996 to 2005, all of 

which involved survey clerks recording the numbers of people recreating by location 

within the project area.31 On-site interviews were conducted with 4,830 visitors to obtain 

information about demographics, recreational-use patterns, attitudes, and opinions. The 

four studies, which are described in license application Appendix E.5-A, Recreational 

Use at the Swan Falls Hydroelectric Project, included the following sampling patterns: 

 

30 To evaluate recreational resources at the project, the Commission requires the 

licensee to prepare and submit a FERC Form 80 (Licensed Hydropower Development 

Recreation Report) every 6 years (see 18 CFR 8.11). Each Form 80 must describe a 

project’s recreation facilities and the level of public use of these facilities. 

31 Idaho Power based its surveys on methods suggested by Malvestuto et al. 

(1978), Malvestuto (1983), and Hoenig et al. (1993). 
80 

• During 1996, the entire area within the project boundary was sampled. A total 

of 470 interviews were conducted to meet the FERC Form 80 filing 

requirements. 

• During 2001, the river corridor along 14 miles of the Snake River was 

sampled. The study area extended downstream from the dam about 2 miles to 

the end of Idaho Power’s property at RM 455.5. The remaining 12 miles 

extended upstream of the dam to where the reservoir transitions to a freeflowing river (RM 469.5). A total of 970 interviews were conducted to meet 

the FERC Form 80 filing requirements. 

• During 2003 and 2005, the 2001 sampling area and the area downstream from 

the end of Idaho Power’s property to a barrier installed by BLM (RM 453.5) 

were sampled. Interviewers conducted 1,737 interviews in 2003 and 1,653 

interviews in 2005. 

Survey results indicate that the majority of recreational users visiting the Swan 

Falls Project were residents of Idaho from the local area on day trips to fish in the Snake 

River. More than 95 percent of the visitors were from Ada or Canyon counties, which 

had an estimated combined population of 564,859 people in 2008 (U.S. Bureau of the 

Census, 2009a, 2009b). Owyhee County, which had an estimated 2008 population of 

10,877 (U.S. Bureau of the Census, 2009c), contributed less than 1 percent of recreational 

use. The location of recreational use in the project area is, to a large extent, defined by 

road access. Use is very low on the western (downstream) end of the project area in 

Owyhee County, where the only road access is provided by a long, mostly unimproved, 

dirt and gravel road from Murphy, Idaho. A small percentage of the visitors were tourists 

who were in the area visiting the Snake River Birds of Prey NCA. 

The majority of the visitors stayed on average between 2.74 hours (recorded in 

1996) and as long as 4.29 hours (recorded in 2003); stays between 3 and 6 hours were the 

most common during all four surveys. The mean group size in the reservoir section 

reported by Idaho Power in 2003 was 3.23 visitors while the tailwater section tended to 

attract smaller groups, with the mean group size of 2.71 recorded by Idaho Power in 

2005. Idaho Power’s data concerning visitors using the Swan Falls Project area show a 

decline in the mean age of visitors, from 36.82 in 2001 to 30.47 in 2005. The age group 

between 18 and 35 consistently contained the highest proportion of visitors. The 

percentage of male visitors was consistently higher than the percentage of females, and 

the percentage of males in the tailwater section was slightly higher than the percentage of 

males in the reservoir section. 

Some major findings from the four studies are listed below. 
81 

• Recreation use is in the neighborhood of 20,000 recreation days annually, with 

survey data reporting 17,699 recreation days in 1996, 24,130 recreation days in 

2003, and 22,596 recreation days in 2005. 32 

• The months with the most use included May, June, July, and August, while 

January consistently had the lowest amount of use. 

• Angling was the most popular activity observed, followed by lounging, 

hiking/walking, hunting, jet skiing, motorcycling/driving off-road vehicles, 

float boating, picnicking, swimming, water skiing, rock climbing, and 

bicycling. 

• The most common activity observed at the dispersed sites was bank angling 

followed by lounging. Idaho Power estimates the hours of overall use at 

individual dispersed sites varied from zero to 7,458 hours annually in 2005. In 

the same year, dispersed-site use in the reservoir area accounted for only 753 

hours of overall dispersed-site use, indicating that the sites downstream of the 

dam receive significantly more use than the reservoir sites. 

Most of the recreational use is concentrated within 1.5 miles of the dam, both 

upstream and down, and is associated with Idaho Power’s only access road paralleling the 

Snake River in Ada County. When Idaho Power conducted its 2001, 2003, and 2005 

recreational-use studies, survey clerks asked the visitors if they had any additional 

comments they would like to share concerning their visit. Of the 902 visitors who 

provided general comments, 132 (14 percent) provided negative comments related 

primarily to litter (e.g., too much litter, need for garbage cans, litter laws need to 

be enforced). 

3.3.5.2 Environmental Effects 

Recreation Management Plan 

To address recreational issues associated with the project, Idaho Power proposes 

to finalize and implement its draft Recreation Management Plan, which would update the 

revised Recreation Plan currently in place.33 This new Recreation Management Plan was 

developed in coordination with other land managers in the project area. Implementation 

of the new plan would provide for continued operation and maintenance of existing 

recreational facilities and Idaho Power’s public safety program, upgrading existing 

 

32 A recreation day is a visit to an area for recreation purposes for any portion of a 

24-hour period. 

33 A revised Recreation Plan was required under an amendment to the license. See 

Order Amending License (Major), Idaho Power Company, December 8, 1989, 49 FERC 

¶62,227. 
82 

facilities, improving some dispersed recreation sites, adding to interpretive and 

informational displays, and modifying the Litter and Sanitation Plan. The various 

elements of the plan are discussed in the sections that follow. 

Developed Sites 

Idaho Power proposes to continue to operate and maintain the five existing project 

recreational facilities (Swan Falls Park, Swan Falls reservoir boat ramp, Swan Falls 

downstream boat launch, the canoe portage trail, and Swan Falls powerhouse museum34

for the term of a new license. Idaho Power proposes the following improvements: 

• Enhance the Swan Falls reservoir boat ramp and install a new vault toilet, 

enlarge and define the parking area for vehicles and trailers, provide parking 

space designated for one average-sized school bus, designate a staging area for 

boats, and widen and steepen the concrete boat ramp; 

• Improve Swan Falls Park and install additional rip rap or a retaining wall, add 

a new dock system with gangway, build one group picnic shelter, add day use 

parking, enhance landscaping with new trees, and provide four additional 

picnic tables near the waterfront; 

• Enhance the Swan Falls downstream boat launch and install a new vault toilet, 

enlarge and define the parking area for vehicles and trailers, designate a 

staging area for boats, build a pre-launch boarding platform, construct a twolane concrete boat ramp, and remove an air compressor; and 

• Improve the canoe portage trail by installing signage. 

In the state of Idaho’s comments filed August 14, 2009, Idaho DPR and Idaho 

DFG endorsed these measures. In a comment letter dated December 20, 2007, and filed 

with Idaho Power’s license application, BLM disclosed information concerning the 

existing air compressor at the downstream boat launch, stating that it did not have the 

appropriate nozzle required to inflate rafts or inflatable kayaks. BLM suggested several 

possible solutions: (1) remove the air pump completely; (2) replace the nozzle with an 

appropriate fitting for raft valves; or (3) provide standard AC outlet plugs for air pumps 

or inflators. On February 24, 2009, Patricia Terry filed comments that her family and 

friends frequent the Snake River near the Swan Falls Project several times a year. She 

requested that Idaho Power leave the air compressor on site, stating that the air 

compressor is helpful for people who like to take inflatable kayaks on the river. 

 

34 Idaho Power’s proposed HPMP includes a provision to improve Swan Falls 

powerhouse museum’s interpretive and education displays and increase days and hours of 

availability to include every Saturday between April 15 and Labor Day, from 10:00 a.m. 

to 4:00 p.m. 
83 

Our Analysis 

The proposed improvements to the existing recreational facilities were developed 

in consultation with the stakeholders. The enhancements would be developed in the areas 

where recreational use is concentrated, within 1.5 miles of the dam. The proposed level 

of recreational development for this project would be appropriate for the level of use 

demonstrated by Idaho Power’s recreational survey data and documented in its recent 

FERC Form 80. Most of the proposed improvements would have a direct beneficial 

effect on recreation users by providing enhanced areas for parking and the effective 

launching and retrieving of boats, and new vault toilets that would improve the 

appearance of the areas and their convenience, and increased public access to the Swan 

Falls powerhouse museum. The improvements would also help reduce the current 

adverse effects on other resources that result from the current lack of defined parking 

spaces and staging areas at the boat ramps. 

Implementation of the draft Recreation Management Plan would also further the 

State of Idaho’s SCORP goals of encouraging healthy living through outdoor recreation 

and recognizing the importance of transportation in planning projects. 

Idaho Power proposes to remove the air compressor at the downstream boat 

launch and use the area to enhance the parking and improve access to and from the boat 

ramp. Idaho Power states that portable 12-volt air compressors and hand pumps are 

common, and it does not believe that continuing to provide an on-site air compressor 

would benefit boaters. 

Removal of the air compressor would provide more open area at the upper right 

edge of the launch. This area would be used for widening the ramp, which would 

ultimately help reduce the traffic congestion associated with the site and improve 

efficiency with boat launching and retrieval activities. The Swan Falls downstream boat 

launch is narrow, which causes congestion and has caused many vehicles to become 

stuck on the slope of the ramp due to lack of traction on the gravel surface. Historically, 

this launch was intended to accommodate canoes, kayaks, and rafts. More recently, 

however, larger motorized boats have been using the ramp, primarily for fishing 

downstream of the dam. Use of the added available space for the proposed enhancements 

would benefit more visitors using this facility than the air compressor, given that 

information on the record shows only two or three families use the equipment perhaps 

two or three times a year. 

Dispersed Sites 

The 26 identified dispersed sites, located both within and outside of the current 

project boundary, present visitors an opportunity to gain access to the reservoir upstream 

of the dam and the river downstream of the dam. Visitor use at these sites, including offroad vehicle use, has created a series of braided roads or multiple access roads to some 

sites and caused severe ruts to form, adversely affecting some upland and riparian 

habitats located within and near the sites. During site surveys in 2002, evidence of 
84 

human waste was present at 11 of the 26 sites, and animal (likely dog) waste was present 

at 4 of the sites. During our February 10, 2008, environmental site review, accumulated 

litter was observed at several of these sites 

Pursuant to the Recreation Management Plan, Idaho Power proposes to define and 

improve 6 of the 26 dispersed sites 35 to contain usage and protect the natural and cultural 

resources of the area and also to enhance visitor experiences. In consultation with the 

stakeholders, Idaho Power selected for improvement two sites upstream of the dam and 

four sites downstream of the dam by taking into account the physical layout of the sites 

and the amount and regularity of recreational use demonstrated in Idaho Power’s 

Recreation Use Study results (Brown, 2002). Physical layout considerations included 

proximity to an improved road and topographical considerations such as ease of access 

and adequate flat land to incorporate enhancement measures. Idaho Power proposes 

improvements for the following dispersed sites: Above the Boat Ramp Site (ABRP), 

Below the Boat Ramp Site (BLOR), Swan Tailwater Fishing Pullout Site (STFP), Swan 

Tailwater Site #13 (ST13), Swan Tailwater Camp (STCM), and Swan Tailwater Site #12 

(ST12) (figure 4). Of these six dispersed recreational sites, only two of the sites (ABRP 

and BLOR) are located within the current project boundary; however, they are not 

currently considered project features. 

Generally, Idaho Power proposes to prevent motorized access to areas adjacent to 

the six selected sites by placing appropriate materials such as fences, boulders, and/or 

berms around the sites. All secondary roads, tertiary roads, and impromptu trails that do 

not directly service the enhanced recreation sites would be closed to motorized 

vehicular traffic. 

Idaho Power’s proposal for the six dispersed recreational sites includes barrier-free 

campsites with a fire ring and compacted gravel surfaces for camping. Two of the 

campsites (located at BLOR) would have tables. Proposed improvements by individual 

dispersed sites would be as follows: 

• ABRP—Define two campsites and restrict additional site growth by installing 

buffer materials. Additionally, improve the road into this area with gravel. 

• BLOR—Define and improve two primary loop roads and provide four 

campsites with pads and fire rings; two sites also would have picnic tables. 

Restrict additional growth of the sites by installing buffer materials. 

• STFP—Designate three campsites. Restrict additional growth of the site by 

installing buffer materials. 

• ST13—Designate one road that accesses the area and add two campsites. 

Restrict additional growth of the site by installing buffer materials. 

 

35 The sites outside of the current project boundary are proposed to be enclosed 

within the new project boundary (see figure 4). 
85 

Figure 4. Location of dispersed recreational sites proposed for improvements 

(Source: Idaho Power, 2009b). 
86 

Figure 4. Location of dispersed recreational sites proposed for improvements (cont.). 
87 

• STCM—Designate a single, two-lane road through the area with a turn-around 

lasso and spur roads to four campsites. Restrict additional growth of the site 

by installing buffer materials. 

• ST12—Improve one road to the site and provide two campsites. Restrict 

additional growth of the site by installing buffer materials. 

Of the 20 remaining dispersed sites, nine are located inside the project boundary 

on Idaho Power lands. To mitigate the effects of visitor use at these nine dispersed 

recreation sites, Idaho Power consulted with FWS, BLM and Idaho DFG to develop a 

Wildlife Habitat Protection and Enhancement Plan (see section 3.3.3., Terrestrial 

Resources). Generally, Idaho Power proposes to recontour and revegetate braided roads 

and riparian and upland areas within these nine sites, and to place boulders or construct 

berms to deter motorized use. Implementation of the Wildlife Habitat Protection and 

Enhancement Plan would include blocking and revegetating roadbeds and restoring other 

disturbed sites by planting native containerized shrub stock and seeding with 

native grasses. 

There are 11 other identified dispersed recreation sites downstream of the dam that 

are located on BLM lands outside of the proposed project boundary. Idaho Power does 

not propose any environmental measures at these 11 sites. 

Idaho Power proposes construction and implementation during years 2 and 3 of 

any new license issued for the project and maintenance of all dispersed recreation sites 

associated with the plan over the life of a new license. Idaho DPR and Idaho DFG both 

recommend implementation of these measures. 

Idaho Power proposes to include within the project boundary the four dispersed 

recreation sites downstream of the dam that are not currently within the project boundary. 

The applicant plans to obtain submerged lands easement rights from the state of Idaho for 

state-owned lands below the OHWM to ensure public access to the shoreline. Lands 

above the OHWM and up to contour 2,360 msl are owned by the applicant. The two 

remaining dispersed sites upstream of the dam are already within the project boundary. 

Our Analysis 

Idaho Power’s proposal for the development of the six dispersed recreation sites 

for public use would improve access for individuals who use the shoreline for fishing, 

dog walking, lounging, and bird watching and would provide barrier-free facilities for the 

disabled. Motorized traffic to newly seeded areas would be restricted year round, which 

would greatly reduce the continued vehicular and human impact on natural and cultural 

resources in areas abutting the sites. Construction activities associated with the 

development of these six sites would occur primarily in the fall and early winter months, 

thereby minimizing conflicts with the majority of the recreational users. Idaho Power 

states that specific construction plans for the dispersed sites would be subject to alteration 

based on the outcome of cultural and rare plant surveys and the associated consultation. 
88 

Idaho Power’s proposal to include within the project boundary all six dispersed 

recreation sites and the access road for 1.7 miles downstream of the dam would ensure 

continued public access and maintenance for all improved dispersed sites during the 

entire term of a new project license. In this instance, the only project access road is an 

existing roadway constructed by Idaho Power (or its predecessors) on Idaho Power land. 

The road terminates at the Murphy gage about 4 river miles downstream from the dam at 

a trailhead owned and managed by BLM. Because this road is the only access to this part 

of the Snake River Canyon and is used by recreationists, including the access road and 

the improved dispersed sites within the project boundary could fulfill a project purpose. 

Terrestrial and cultural resources would also benefit from inclusion of the access 

road36 downstream of the dam to RM 455.4 as a project feature within the project 

boundary (see sections 3.3.3, Terrestrial Resources, and section 3.3.7, Cultural 

Resources). Revision of the Recreation Management Plan to address the HPMP findings, 

along with consultation with the Idaho SHPO, would help to protect cultural resources 

that might be affected by the recreation improvements. 

Litter and Sanitation Plan 

Idaho Power proposes to provide additional vault toilets and dumpsters and to 

implement the Litter and Sanitation Plan within the project boundary and downstream to 

RM 453.4. Dumpsters would be placed at three locations: Swan Falls reservoir boat 

ramp, Swan Falls Park, and the Swan Falls downstream boat launch. Vault toilets would 

also be placed at three sites: Swan Falls reservoir boat ramp, Swan Falls downstream 

boat launch, and dispersed site ST12. Two signs, one upstream of the dam and one 

downstream, would encourage visitors to pack out what they pack in (carry-in/carry-out). 

In the State of Idaho’s comments filed August 14, 2009, Idaho DPR and Idaho DFG both 

recommended implementation of this plan. 

Our Analysis 

The Litter and Sanitation Plan would address the litter and sanitation concerns 

expressed by the visitors in response to Idaho Power’s recreational surveys. The plan 

would have a direct beneficial effect on the recreational experiences of visitors by 

providing for dumpsters, regularly scheduled litter pickups, signage to encourage users to 

carry-in/carry-out, and additional public toilets at designated locations within the project 

boundary. However, Idaho Power proposes to implement the plan downstream of the 

Swan Falls dam to RM 453.4, which is 2 miles beyond the proposed project boundary at 

RM 455.4. Although there would be a benefit to BLM and recreationists to extending the 

Litter and Sanitation Plan that far, recreational activities in that area would not be related 

to the use of project lands; therefore, implementation of the plan in the area beyond RM 

455.4 would not fulfill a project purpose. 

 

36 The access road from the main road to the powerhouse is within the current 

project boundary. 
89 

Interpretation and Education 

Idaho Power proposes a framework to guide interpretation and education 

enhancements at specific recreation sites within the project boundary, including 

coordination with the proposed HPMP (section 3.3.7, Cultural Resources) to blend 

project information and provide project-wide consistency. Idaho Power proposes to place 

interpretation and education panels at four specific areas within the project boundary, 

which would include the following information and themes: 

• Swan Falls reservoir boat ramp 

 Detailed area location map in coordination with FERC Part 8 Sign37

 Boating safety 

 Game fish and their habitat 

• Swan Falls Park 

 Detailed area location map in coordination with FERC Part 8 Sign 

 Snake River Birds of Prey NCA 

 Swan Falls Hydroelectric Project History 

 History of the Bonneville Flood 

• Canoe portage trail 

 Portage sign containing information on direction and safety 

 Whitewater boating safety 

• Swan Falls downstream boat launch 

 Detailed area location map in coordination with FERC Part 8 Sign 

 Whitewater boating safety 

 Sturgeon history. 

 

37 Pursuant to 18 CFR, section 8.2, a licensee is required to post and maintain a 

conspicuous sign at all points of public access as required by the license. Each sign, 

referred to as a FERC Part 8 sign, must contain the name and number of the project, the 

owner of the project, a statement that it is licensed by the Commission, directions to the 

areas of the project that are available for public recreation use, permissible times of 

access and activities, and other regulations regarding such use. The Part 8 sign must also 

advise that further information may be obtained at local offices of the licensee in the 

vicinity of the project. In addition, the licensee is required to post at such locations 

conspicuous notice that the recreation facilities are open to all members of the public 

without discrimination. 
90 

The overall design package would consider colors and design elements that tie one 

exhibit to another with uniform typeface and sizes. The final design package would be 

subject to Idaho Power and appropriate agency approval. In the State of Idaho’s 

comment letter filed August 14, 2009, Idaho DPR and Idaho DFG both recommended 

implementation of this plan. 

Our Analysis 

Finalizing and implementing the Interpretation and Education Plan in consultation 

with stakeholders as part of the draft Recreation Management Plan would establish a 

consistent method to provide visitors with project information and important safety 

messages. In its draft Recreation Management Plan, Idaho Power identified likely 

locations, themes, stories, objectives, and options for structures and sign displays within 

the Swan Falls Hydroelectric Project area. Particularly, Idaho Power’s proposed panel 

with the theme of Snake River Birds of Prey NCA would focus on the importance of 

birds of prey and would further educate visitors, which could help reduce illegal activities 

such as shooting in the area (see section 3.3.2, Terrestrial Resources). Because Idaho 

Power states that specific displays would be subject to alteration based on the outcome of 

consultation, a final Recreation Management Plan filed with the Commission for 

approval would ensure that the proper consultation has occurred and that the final sitespecific information could be assessed properly. Development of such a plan would have 

a direct beneficial effect on the safe recreational experiences of visitors. Idaho Power’s 

proposal to finalize and implement the Interpretation and Education Plan as part of its 

Recreation Management Plan would directly address the stated goal and objectives in 

Idaho’s SCORP to develop a unified strategy for delivering outdoor recreation education 

to the public. 

Interagency Recreation Working Group 

Idaho DPR recommends the establishment of an interagency recreation working 

group that convenes every 6 years to review FERC Form 80 information and make 

recommendations concerning future management. Idaho DPR also recommends that it be 

designated a member of the recreation working group. 

Our Analysis 

Idaho Power’s draft Recreation Management Plan does not provide a framework 

for the continued monitoring of recreation facilities, dispersed recreation sites, and usage. 

Recreational use monitoring and assessment of recreation-related effects on lands within 

the project boundary as a component of gathering data for FERC Form 80 and as part of 

the Recreation Management Plan would allow Idaho Power and stakeholders to consider 

measures to address recreational use, including dispersed use, over the term of the 

new license. 

In addition, it would be beneficial if the Idaho SHPO were to become a member of 

this Recreation Working Group, and if Idaho Power’s historic properties management 

coordinator participated as well. In its application and proposed HPMP, Idaho Power 
91 

includes measures for ongoing monitoring through the term of any license issued and as 

necessary, further treatment of sites potentially subject to adverse effects as a result of 

recreational use. Coordination with the Idaho SHPO on this issue would be helpful in 

ensuring that cultural resources are appropriately considered. 

Stakeholders designated as members of this Recreation Working Group could 

include Idaho DPR, Idaho DFG, Idaho SHPO, and BLM. It could be beneficial for Idaho 

Power to file every 6 years, in coordination with its filing of the FERC Form 80, a 

Recreation Monitoring Report that would summarize the Recreation Working Group’s 

monitoring activities and data and relaying to the Commission any recommendations for 

future recreation management. 

Effects of Fish, Wildlife, and Water Quality Measures on Recreation 

Idaho Power proposes to implement various plans to address the project’s effects 

on natural and cultural resources due to the proposed operation and maintenance of the 

project over the term of a new license. Among other measures, Idaho Power proposes to 

provide an instantaneous minimum flow of 3,900 cfs downstream of the dam from April 

1 to October 31 and 5,600 cfs from November 1 to March 31, and to continue to remove 

and dispose of aquatic macrophytes and debris that accumulate on the project trash racks 

(section 3.3.2, Aquatic Resources). Idaho Power also proposes to implement its Noxious 

Weed Management Plan (section 3.3.3, Terrestrial Resources). 

Our Analysis 

Idaho Power’s proposal to remove nutrients and oxygen-demanding material from 

the river would directly address the state of Idaho’s goal in its SCORP to recognize that 

“water is an increasingly precious resource.” Implementation of the Noxious Weed 

Management Plan would directly address the goal in Idaho’s SCORP to minimize the 

impact of invasive species. These measures would have an indirect beneficial effect on 

recreation by furthering these SCORP goals and objectives and would have a direct 

beneficial effect on recreational users by improving water quality. 

Idaho Power’s proposal to improve the six dispersed recreation sites would help 

concentrate recreation use and thereby protect environmental measures. 

Swan Falls Powerhouse Museum 

Early in the relicensing process, Idaho Power consulted with BLM to develop, 

conduct, and review recreational studies related to the project. During this consultation, 

BLM suggested that the Swan Falls powerhouse museum should be open to the general 

public, at a minimum, during the spring and summer months on Fridays, Saturdays, and 

Sundays. Idaho Power does not propose to open the facility on Fridays and Sundays, 

however, stating that the current level of visitor interest and use does not merit the costs 

associated with opening the museum more than one day per week. 
92 

Idaho Power proposes to open the historic powerhouse to the visiting public every 

Saturday between April 15 and Labor Day from 10:00 a.m. to 4:00 p.m. Idaho Power 

proposes to provide a uniformed security guard to be present to ensure visitor safety and 

the security of company property during these public hours. Measures specific to 

enhancing interpretive resources are contained in the Swan Falls HPMP. 

Our Analysis 

Results of four recreational surveys, which are described in license application 

Appendix E.5-A, Recreational Use at the Swan Falls Hydroelectric Project, indicate that 

the months with the most visitor use in the area of the project include May, June, July, 

and August. Implementation of Idaho Power’s proposal to open the Swan Falls 

powerhouse museum between April 15 and Labor Day would directly benefit visitors’ 

experiences during the heaviest visitation period. Based on the latest FERC Form 80 

data, the Swan Falls Project had a total of about 21,534 visitors during the 2001 calendar 

year and visitation to interpretive displays was low, equal to or less than 40 percent of 

full capacity. Idaho Power proposes to monitor and assess visitor use and interest in the 

historic powerhouse and would consider expanding visitation hours in the future if 

demand and use support the need to do so. 

The proposed level of recreational development for this project would be 

consistent with the level of use shown by the recreational survey data and documented in 

the latest FERC Form 80. Establishment of the Interagency Recreation Working Group 

discussed above would help provide a framework for future recreational use monitoring 

and assessment of recreation-related effects on lands within the project boundary as a 

component of gathering data for the FERC Form 80 and as part of the Recreation 

Management Plan. This would allow Idaho Power and stakeholders to consider measures 

to address recreational use of the Swan Falls powerhouse museum over the term of a 

new license. 

Public Safety Plan 

Idaho Power proposes to continue implementation of its June 2008 Public Safety 

Plan, which is included as Technical Report Appendix H.13-A in Idaho Power’s license 

application (Idaho Power, 2008c). The Public Safety Plan includes the following 

measures: 

• fencing at the historic display and spillway; 

• public warning siren and strobe light at the spillway that activates 1 minute 

prior to any spillgate operation; 

• buoy line with 21 buoys and 8 danger signs located approximately 325 feet 

upstream from the powerhouse and aerial buoys located downstream of the 

spillgates; 
93 

• signage to include 15 caution, warning, danger, and directional signs to inform 

the public on how to safely conduct themselves while enjoying the resources at 

the project; 

• photo cell lighting to include 6 white lights located on the spillway deck, 4 

white lights located on the downstream side of the generator deck, and 15 

white lights located on the upstream face of the powerhouse; and 

• an inspection schedule that includes regular damage and operational 

inspections. 

In the State of Idaho’s comments filed August 14, 2009, Idaho DPR and Idaho 

DFG both recommended implementation of this plan. 

Our Analysis 

Idaho Power has a responsibility for public safety and to ensure public access 

under parts 12 and 2.7 of the Commission’s regulations. Idaho Power proposes to 

continue implementation of its plan to install, operate, and maintain signs, lights, sirens, 

barriers, or other safety devices reasonably necessary to warn the public of fluctuations in 

flow from the project or otherwise to protect the public in the use of project lands and 

waters. The proposed measures include monitoring of the signs, lights, sirens, barriers, 

and other safety devices throughout the term of the license and appropriate maintenance 

of the devices. 

One particular sign worth noting is the proposed warning sign titled “NO 

SHOOTING”, which would be 18 inches by 24 inches in blue lettering with a white 

background. Idaho Power proposes to place one such sign near the reservoir boat dock 

and one sign east of the restrooms off the main access road. These signs would both 

improve personal safety and benefit birds of prey, which are subject to illegal shooting in 

the area (see section 3.3.2, Terrestrial Resources). 

The proposed measures listed above and outlined in the Public Safety Plan appear 

to be reasonable and appropriate to ensure public safety at the project. 

3.3.6 Land Use and Aesthetic Resources 

3.3.6.1 Affected Environment 

Land Use 

The existing project boundary surrounding the Swan Falls Project encompasses 

2,192 acres. Idaho Power owns 584 acres, primarily on the northeast side of the river at 

the tailrace, dam, and reservoir upstream of Swan Falls dam. Idaho Power also owns 

some land on the southwest side of the river from the dam upstream for approximately 1 

mile. These lands are used by Idaho Power primarily for the operation and maintenance 

of the Swan Falls Project under the terms of its current license. In addition, Idaho Power 
94 

has a program for administering its current policy regarding the permitting of piers, 

docks, and other shoreline facilities associated with project lands and waters. This 

permitting policy allows permits for private boat docks and similar structures only for 

applicants who own or lease land adjacent to a project reservoir or adjacent to Idaho 

Power-owned freeboard land (that is, land above the OHWM). 

Long-term land management direction of federal lands within the NCA is 

provided by BLM’s approved Record of Decision and Resource Management Plan dated 

September 2008 (BLM, 2008). Several special management areas have been established 

by BLM in and adjacent to the existing project boundary, including the following: 

• The western end of the Snake River Canyon within the NCA, which includes 

the Swan Falls Project area, is designated as a Special Recreation Management 

Area, which provides for a variety of river- and land-based recreational 

opportunities. 

• Most of the NCA is declared a Designated Vehicle Management Area, 

requiring that vehicles remain on designated roads or trails (except for 

administrative purposes). 

• On the southwest side of the river, the project area is included within a 

designated avoidance, or exclusion, area for major realty actions because of 

recreational controls, sensitive plant issues, and paleontological concerns. The 

Guffey Butte–Black Butte Archaeological District (Archaeological District) 

Area of Critical Environmental Concern includes all land in the project area 

southwest of the river. 

• BLM’s management plan relevant to the Swan Falls Project area includes a 

year-round closure to shooting rifles and pistols within 0.5 mile of the Snake 

River downstream from Grand View, Idaho (located about 16 river miles 

upstream of the Swan Falls Project boundary) and a closure of the same area to 

all firearms from February 15 through August 31 each year. 

• The project area lies within three grazing allotments: the Sunnyside Winter 

Allotment on the northeast side of the river and the Sinker Butte and Montini 

Fenced Federal Range38 allotments on the southwest side of the river. An area 

on the southwest side of the river downstream of the project area has been 

withdrawn from grazing. Other uses allowed in the area include recreation and 

mineral extraction, as long as these activities are consistent with the protection 

of raptors and their prey. 

The state of Idaho owns and manages 58 acres of land within the current project 

boundary; the land uses on these parcels are similar to those listed above. The remaining 

 

38 Fenced Federal Range is generally defined as a small amount of public land 

fenced within a large amount of private land. 
95 

84 acres of land within the project boundary are private lands used primarily for 

cultivated agriculture. No private residences occur in or near the project area other than 

the six residences inhabited by employees or lessees of Idaho Power. Table 11 depicts 

the current land use within the project boundary. 

Table 11. Current land use within the Swan Falls Project boundary (Source: Idaho 

Power Company, 2008a, as modified by staff). 

Land Use Project Acres 

Urban or Developed 20 

Agriculture 47 

Rangeland 1,188 

Total Land 1,255 

Water 937 

Total Acres 2,192 

The Snake River in the location of the Swan Falls Project forms the boundary 

between Ada County, the most populous county in the state, and Owyhee County, a very 

rural area with extremely low population density. For further discussion of population 

characteristics, see section 3.3.8, Socioeconomics. 

Aesthetic Resources 

Project Setting 

Swan Falls Road, which is located on the plateau above the Snake River Canyon, 

has been designated part of the Western Heritage Historic Byway by the Idaho 

Transportation Department. The Byway extends a total of 40 miles beginning on Idaho 

State Highway 69 near the southern boundary of the city of Meridian, near Kuna, and 

ending at Swan Falls dam. The Byway offers views of high desert features with historic, 

scenic, and geologic elements. 
96 

Initiated by the Western Heritage Foundation, the Western Heritage Historic 

Byway Corridor Management Plan, dated September 2004, 39 is targeted at enhancing the 

economy by encouraging activities related to the area’s historic character, including 

adding interpretive signs, picnic areas, trails, and parking; upgrading the boat docks, 

ramps and trails; and establishing a geologic trail (Planmakers and J-U-B Engineers, 

2004). The efforts of the Western Heritage Foundation and its partners have resulted in 

the erection of several interpretive signs at points of interest between the community of 

Kuna and the Swan Falls Project. One such sign is located at the pull-off area where 

Swan Falls Road ends and the project access road begins. This pull-off area provides 

limited parking space and a sweeping view of the canyon below. The Snake River 

Canyon is an abrupt drop of approximately 3,000 feet from the flat, open plains above. 

Black basalt walls form sheer cliffs down to the river. At the dam, the canyon width is 

approximately 1,000 feet and the river takes up somewhat less than one-quarter of that 

width, with narrow bands of land on either side. Aside from the Swan Falls Project itself, 

very few human-made structures exist either above or below the canyon rim. 

The project road is the only improved access into the Snake River Canyon in Ada 

County, which includes Boise and other population centers. The canyon is accessible 

from several other locations, both upstream and downstream of the project, but the Swan 

Falls Project access provides a close-to-home glimpse of magnificent resources seen by 

relatively few people. 

Visual Resource Management 

BLM manages its lands in accordance with its Visual Resource Management 

(VRM) System. The system designates landscape units in four classes that indicate the 

overall significance of the visual environment and establishes objectives for the 

management of each class in order to define the level of change from a proposed project 

that is acceptable in that class. By comparing the effects from a project to the established 

visual objective for that area, the visual acceptability of that project and mitigation 

measures needed to decrease the visual contrast are determined. The four visual 

management classes and their objectives are described below: 

• Class I—the objective of this class is to preserve the existing character of the 

landscape. This class provides for natural ecological changes; however, it does 

 

39 The Western Heritage Foundation invited representatives from various local 

interests and agencies to help develop the corridor management plan. Partners involved 

in the plan’s development include Western Heritage Foundation, Kuna Chamber of 

Commerce, Ada County Parks and Recreation, Canyon County Parks and Recreation, 

Ada County Sheriff’s Department, Mountain Post–Digital Imaging, City of Meridian, 

Ada County Highway District, City of Kuna, several private citizens, City of Melba, 

Echo Films, City of Kuna, Ada County Historic Preservation Council, BLM, Kuna 

School District, Idaho Power, and Idaho Department of Transportation. 
97 

not preclude very limited management activity. The level of change to the 

characteristic (background) landscape should be very low and must not 

attract attention. 

• Class II—the objective of this class is to retain the existing character of the 

landscape. The level of change to the characteristic landscape should be low. 

Management activities may be seen, but should not attract the attention of the 

casual observer. Any changes must repeat the basic elements of form, line, 

color, and texture found in the predominant natural features of the 

characteristic landscape. 

• Class III—the objective of this class is to partially retain the existing character 

of the landscape. The level of change to the characteristic landscape should be 

moderate. Management activities may attract attention but should not 

dominate the view of the casual observer. Changes should repeat the basic 

elements found in the predominant natural features of the 

characteristic landscape. 

• Class IV—the objective of this class is to provide for management activities 

that require major modification of the existing character of the landscape. The 

level of change to the characteristic landscape can be high. These management 

activities may dominate the view and be the major focus of viewer attention. 

However, every attempt should be made to minimize the impact of these 

activities through careful location, minimal disturbance, and repeating the 

basic elements. 

BLM designates the area on both sides of the river at the developed area just 

upstream of Swan Falls dam and the area downstream of the dam as VRM Class III, 

Partial Retention. Upstream from the developed area near the dam, the VRM designation 

is Class II, Retention (BLM, 2008). 

Idaho Power, in consultation with resource agencies and stakeholders, conducted 

an aesthetic conditions and project impact assessment to evaluate the visual compatibility 

of project features with the surrounding landscapes. The aesthetic character and visual 

effects were evaluated using BLM’s VRM System. Four KOPs in the project area were 

identified for this assessment: (1) the pull-off at the top of the cliff above the dam and 

powerhouse; (2) the parking and restroom area near the powerhouse; (3) the boat launch 

just upstream of the dam and powerhouse; and (4) the boat launch area just downstream 

of the dam and powerhouse. 

From KOP 1, the observer can view essentially all project features and several 

miles up and down the river. A single, relatively small transmission line ascends the hill 

from the powerhouse. The dam forms a light-colored line perpendicular to the dark water 

of the river, with vertical features extending from the dam. Both old and new sections of 
98 

the powerhouse are also light in color, in contrast to the dark water. The old powerhouse 

appears as a large form sitting above the middle of the river. The clubhouse40 and a 

newer house close by are readily apparent due to their reflective, light color, and the grass 

and ornamental shrubs surrounding them. The line of a road leads to the south where 

first a small red building and then five newer, very light-colored houses appear against 

the dark tan of soils and vegetation. An open area near the river with several boat docks 

lies near the end of the road. From this vantage, the viewer sees unexpected, yet 

intriguing, views of the old powerhouse’s architecture, resembling a grand residence or 

castle in the middle of the river (see cover photo). Considerable contrast with the natural 

landscape occurs from project facilities, but the development also creates a great deal of 

interest for the viewer upon finding human occupation in what seems to be the middle of 

nowhere. This KOP may be the most sensitive of the four since, for some visitors, it will 

factor into their decision of whether or not to descend the steep, winding road into 

the canyon. 

Views from KOP 2 are panoramic, and primarily in the foreground. The old 

powerhouse and visitors’ center, with its interesting architecture, is an object of attention. 

The new portion of the powerhouse and adjoining shop are more industrial in appearance 

and of less interest. The transmission line going up the cliff from the powerhouse is 

notable in its steep ascent. The gray, wrought iron fencing is substantial in appearance. 

A kiosk contains interpretive signs of interest, but its architecture is quite different from 

the other structures. Beyond the kiosk is the restroom, which is made of primarily gray to 

tan cinder block and a lighter color metal roof. The wood on this building needs paint. 

The slatted chain link fence, keeping visitors away from equipment next to the restroom, 

is also in need of maintenance. 

Farther away, the old clubhouse and a somewhat more modern house draw the 

curious visitor into a shaded, grassy area that is extremely welcoming on hot summer 

days. Several old stone walls and mature landscaping suggest that this area was probably 

developed as part of the original project. Several picnic tables are located on these 

grounds, interspersed with large cottonwood trees. Poplar and pine trees are located 

nearer the houses. Small areas of riparian vegetation can be seen upstream, along with 

the buoy line and yellow buoys just upstream of the dam. The low profile, linear dam 

extending out from the powerhouse has numerous vertical elements. 

Past the picnic area and clubhouse and heading toward KOP 3, visitors can see an 

old orchard and a pasture, along with a small, red, barn-like building with pens. Poles 

and trestles are piled nearby. Five newer residences of a light color are situated above the 

road and are visible along with associated vehicles and travel trailers. As one continues 

 

40 The building referred to in company documents and by employees as the 

clubhouse is also referred to as the Swan Falls boardinghouse because of its historical use 

in that capacity. It is located just upstream from the dam and powerhouse. For 

information on this structure see section 3.3.7, Cultural Resources. 
99 

upstream from KOP 2 and passes through the area, the signage that appears is 

inconsistent and irregular, and appears in need of maintenance. 

KOP 3 includes the boat launch area located upstream of the dam, which consists 

of an open, partially graveled area; two docks (one wood and one metal); and a port-apotty. The area is visually unattractive because it is poorly defined. The orange port-apotty contrasts strongly with the surrounding landscape, and trash is often left by users. 

From the boat docks, however, one can see areas of riparian vegetation along the banks 

and the project reservoir, which appears as a slow-moving river rather than a lake. 

Perhaps a mile or so upstream, on the opposite bank, a white pump house is visible. 

Downstream, the old powerhouse is the most noticeable element, standing above the 

river. The dam, because of its low profile, is not especially noticeable, except for the 

numerous vertical elements rising from it. The project housing can be seen in 

the distance. 

KOP 4, which includes a second boat launch area, is located just downstream of 

the dam. The powerhouses and dam are in the foreground view here. A large crane and 

the newer, more industrial-looking powerhouse present a more operational appearance 

than the view from the upstream side. The architecture of the old powerhouse, however, 

remains of great interest from this viewpoint, and is even more pronounced because the 

water level is lower and more of the building is visible. During frequent releases, water 

can be seen rushing through the gates and spreading across the width of the spillway. On 

the road where one turns into this area, there is a port-a-potty and a compressor that is 

available for inflating rafts. Looking back toward the cliffs, one can see the relatively 

small transmission line traversing the hillside and into the cliffs. 

Northwest (downstream) of the dam, fences are visible on either side of the road 

for a short distance. Vegetation is natural. Approximately 0.25 mile downstream of the 

dam is an area of ongoing habitat restoration. Approximately 0.50 mile downstream of 

the dam on the river side of the road is a cleared area called the lay-down yard, where 

material taken off the trash racks is deposited. From the road, the view is somewhat 

screened by trees and shrubs that are in relatively poor condition. Further down the road 

(on the side away from the river), BLM has made efforts to use rocks and boulders to 

block trails created by off-road vehicles. Campsites have been designated with rockformed fire pits on the river side of the road. Farther downstream, soil and vegetation 

damage by off-road vehicles is also occurring on Idaho Power-owned land outside of the 

project boundary. Some visual contrast in texture, line, and color occurs as a result of the 

destruction of vegetation and the ridges and swales left in the soil, although this is not 

seen from the KOPs. 

3.3.6.2 Environmental Effects 

Project Boundary Revisions 

Idaho Power proposes to include within the project boundary land that it owns 

downstream of the dam on the northeast side of the Snake River in Ada County. Idaho 
100 

Power proposes the addition of this land because it is needed for project purposes; that is, 

it is needed to incorporate into the project boundary dispersed recreation sites proposed 

for enhancement in its Recreation Management Plan. The lands added within the project 

boundary would also include 8.4 acres of roadbeds and 36.9 acres of other disturbed sites 

to be revegetated by planting native, containerized shrub stock and seeding with native 

grasses, as proposed in the Wildlife Habitat Protection and Enhancement Plan. In 

addition, implementation of the proposed HPMP would include measures for monitoring 

and, as necessary, further treatment of sites potentially subject to adverse effects as a 

result of recreational use. 

To maintain and manage the four dispersed recreation sites that are currently 

outside the project boundary and are proposed for enhancement, Idaho Power proposes to 

include the sites as project features and expand the project boundary for approximately 2 

miles downstream of the dam. This expanded project boundary would include all land on 

the northeast side of the river between the OHWM up to the 2,360-foot elevation contour 

starting at the northern (existing) project boundary and merging with the Idaho Power 

property boundary, which is approximately 1.7 miles downstream of Swan Falls dam.41 

A private parcel located approximately 1.5 miles downstream of Swan Falls dam is 

specifically excluded from the proposed FERC project boundary. In addition, Idaho 

Power proposes to enclose within the project boundary land located on the immediate 

west side of the dam to include the canoe/kayak portage trail. 

Idaho Power proposes to remove 791 acres from the current project boundary, 

most of which are located upstream of the dam, and add 192 acres to the current project 

boundary downstream of the dam. This would result in a net reduction of 599 acres 

within the project boundary. 

Idaho Power generally used the 2,318-foot elevation contour to delineate the 

proposed project boundary for the upstream (reservoir) reach. The 2,318-foot elevation 

contour is the reservoir level during the maximum spillway design event (105,112 cfs) at 

Swan Falls dam. Under these conditions, the area within the reservoir below this contour 

would be completely flooded; therefore, it would be needed for project purposes. There 

are two additional areas needed for project purposes that lie outside the 2,318-foot 

elevation contour. First, on the northeast side of the reservoir, Idaho Power proposes to 

keep the current project boundary to encompass two dispersed recreation sites where 

improvements are proposed. Second, on the southwest (Owyhee County) side of the 

reservoir at the dam, the project boundary would be modified to encompass the 

canoe/kayak portage trail. It would then resume at the 2,318-foot elevation contour. 

 

41 Idaho Power also plans to obtain submerged land easements (lands below the 

OHWM) from the Idaho Department of Lands, as well as any other state and federal 

permits necessary to ensure public access below the OHWM at the proposed recreation 

sites located downstream of the dam. 
101 

Idaho Power proposes to pursue flood easements for 3 parcels of private lands that are 

situated below the proposed 2,318-foot contour. Idaho Power states in its proposal that 

all of its proposed recreational and terrestrial protection, mitigation, and enhancement 

measures would be included within the new project boundary. Table 12 summarizes the 

ownership of lands located within both the current and proposed project boundaries. 

Table 12. Ownership of lands located within the current and proposed project 

boundary. 

Ownership of 

Project Lands 

Current Project 

Boundary 

Acreagea

Proposed Project 

Boundary 

Acreageb

Difference in Acreage 

Between the Current 

and Proposed Project 

Boundary 

Idaho Power 584 438 –146 

Private 84 16 –68 

Bureau of Land 

Management 

529 186 –343 

State of Idaho 58 25 –33 

Total Land Area 1,255 665 -590 

Water 937 928 –9 

Total Acres within 

Project Boundary 

2,192 1,593 –599 

a Source: Idaho Power (2008a). 

b Source: Idaho Power (2009c). 

Our Analysis 

According to 18 CFR 4.51(h), land included within a project’s boundary must 

enclose those lands necessary for operation and maintenance of the project and for other 

project purposes, such as recreation, shoreline control, or protection of environmental 

resources. Idaho Power’s proposal to include as project features within the project 

boundary the canoe portage trail and the dispersed recreation sites proposed for 

improvements would serve project purposes. As stated in section 3.3.5.2, Recreation 

Resources, Environmental Effects, the only project access road is an existing roadway 

constructed by Idaho Power (or its predecessors) on Idaho Power land. The road 

terminates at the Murphy gage (approximately 4 river miles downriver from the dam) at a 

trailhead owned and managed by BLM. Because this project access road is the only 

access to this part of the canyon and is used by recreationists, incorporating and 

maintaining this access road within the project boundary would be a project benefit. 
102 

Idaho Power’s proposal to include the dispersed recreation sites and the 

canoe/kayak portage trail within the project boundary would ensure that public access is 

maintained during the term of a project license, which would have a direct beneficial 

effect on recreational access. This proposal would also protect cultural and natural 

resources in the area by focusing recreational activity within formal and managed public 

access points. 

Idaho Power’s proposal to include within the project boundary the lands that 

would be revegetated and maintained under the Wildlife Habitat Protection and 

Enhancement Plan would be beneficial because it would allow for Commission oversight 

of the long-term management of these lands, which would include an effectiveness 

monitoring protocol that Idaho Power would follow to evaluate planting success, with 

provisions for consulting with the agencies 10 years after implementation to determine 

whether any remedial actions are needed. Lands managed under the HPMP would 

likewise allow for Commission oversight of provisions for monitoring and, as necessary, 

further treatment of sites potentially subject to adverse effects as a result of 

recreational use. 

With regard to Idaho Power’s proposal to remove from the project boundary most 

of the lands located above the 2,318-foot elevation contour, we note that lands above the 

contour are not affected by project operation or uses, and therefore are not needed for 

project purposes. 

Permitting Policies for Non-Project Use of Project Lands and Waters 

Idaho Power proposes to continue implementing its policies for permitting piers, 

boat docks, and other facilities (non-project use of project lands and waters). Idaho DPR 

recommends the establishment of an interagency land use working group that would 

convene every 6 years to review FERC Form 80 information and make recommendations 

concerning future management. Idaho DPR also recommends that it be designated a 

member of the land use working group. 

Our Analysis 

Idaho Power is responsible for reviewing permit applications for certain types of 

use and occupancy of project lands and waters. Because Idaho Power and the federal and 

state governments own a majority of the land within the project boundary and on adjacent 

land, land uses and requests for development are very limited. Although there are 84 

acres of private land within the existing project boundary, the proposed project boundary 

includes only 16 acres of private land in non-contiguous parcels. It is unclear how the 

recommendation for a land use working group would benefit future management 

decisions on only 16 acres of land and land use within the project boundary. 

Establishment of separate land use working group in addition to the recreation working 

group would be unnecessary and would duplicate Idaho Power’s efforts. 
103 

Resource Management Plan 

Idaho Power proposes to finalize and implement the Resource Management Plan 

that would guide staff working with hydroelectric operations and maintenance of the 

Swan Falls Project. The framework provided in the proposed plan includes references to 

project plans, BLM management plans, and potential consultation requirements with the 

Idaho SHPO through the Idaho Power historic properties management coordinator. Idaho 

Power proposes to use the plan as a resource for Idaho Power staff to ensure decisions are 

made in coordination with project wildlife, botanical, aquatic, recreational, visual, 

cultural, and geological/soil resource plans; consistent with the purpose of the Snake 

River Birds of Prey NCA; and consistent with all applicable state agency issued 

certificates and rules and regulations. In the State of Idaho’s comments filed August 14, 

2009, Idaho DPR and Idaho DFG both recommended implementation of this measure. 

Our Analysis 

Idaho Power’s proposal to finalize and implement the proposed Resource 

Management Plan would serve as the guiding management strategy for the Swan Falls 

Project. It would provide a framework for proactive and coordinated decision-making 

that would ensure continued operations and public use in a manner that conserves and 

protects its cultural and natural resources. The Resource Management Plan would

provide an on-site resource that would help operators to help guide decisions that could 

affect the cultural and natural resources within the project boundary during the day-today operation and maintenance of the project. Resource Management Plan’s references 

to project plans, BLM management plans, and Idaho SHPO consultation requirements 

could guide decision makers through the project, federal, and state plans that apply to the 

project and that need to be considered during project operation and maintenance 

activities. The Resource Management Plan would have a direct beneficial effect on the 

management of the lands within the project boundary over the term of the license. 

Visual Guidelines Plan 

Idaho Power proposes to implement its Visual Guidelines Plan to ensure that any 

new project construction considers the protection of visual resources from important 

viewpoints. Idaho Power proposes applying the BLM’s VRM standards at intervals of 

routine, ongoing and needed maintenance on the buildings in the employee housing area. 

In general, Idaho DPR supports the BLM standard; however, Idaho DPR states that 

specific approaches are not addressed concerning material colors for structures or plant 

species used for vegetative planting. Idaho DPR recommends the development of 

aesthetic guidelines for building structures and vegetative planting at the recreation 

facilities and in the employee housing area. 

Idaho Power also proposes to modify the colors of its project houses to blend with 

soils and vegetation, paint the wooden elements associated with KOP 2 (the parking and 

restroom at Swan Falls Park near the powerhouse), and establish screening around the 
104 

lay-down yard to reduce visual effects on the aesthetic resources at the project. Both 

Idaho DPR and Idaho DFG recommend implementation of these measures. 

Our Analysis 

The BLM VRM rating for the project area is Class III, Partial Retention, in the 

developed area near the dam and downstream of the dam. The BLM VRM rating is Class 

II, Retention, upstream of the developed area. Idaho Power’s proposal to modify the 

colors of its project houses to blend with soils and vegetation, paint the wooden elements 

associated with KOP 2, establish screening around the lay-down yard, and implement its 

Visual Guidelines Plan would reduce current adverse visual effects at the project. Idaho 

DPR’s recommendation that Idaho Power include specific approaches concerning 

material colors for structures and plant species used for vegetative planting, along with 

consultation with Idaho DPR, would help ensure that project changes would have 

minimal effects on visual resources in the project area. In addition, because of the 

proximity of BLM lands, it would be beneficial if BLM were added to this consultation 

process. Useful revisions to the Visual Guidelines Plan could include the following 

information: 

• A list of neutral paint color schemes identified in consultation with BLM and 

Idaho DPR. 

• A list of species of vegetation identified in consultation with BLM and Idaho 

DPR for vegetative planting and/or aesthetic screening purposes. 

• A list of the construction materials that could be used for maintaining existing 

buildings or for new building construction identified in consultation with BLM 

and Idaho DPR. 

Revising the Visual Guidelines Plan to contain these elements could have a direct 

beneficial effect on aesthetic resources at the project. 

Interagency Aesthetic Working Group 

The Idaho DPR recommends the establishment of an interagency aesthetic 

working group that convenes every 6 years to review FERC Form 80 information and 

make recommendations concerning future management. The Idaho DPR also 

recommends that it be designated a member of the aesthetic working group. 

Our Analysis 

Idaho Power does not propose any large or ongoing construction activities over the 

term of a new license. As noted above, there are 84 acres of private land within the 

existing project boundary but only 16 acres of land in non-contiguous private parcels 

within the proposed project boundary. Given that Idaho Power proposes implementation 

of its Visual Guidelines Plan, which would include provisions for consultation with 

stakeholders on decisions being made in regard to aesthetic resources, it is unclear how 

the recommendation for an aesthetics working group would benefit future management 

decisions on aesthetic resources within the project boundary. Establishment of a separate 
105 

aesthetics working group in addition to the recreation working group would be 

unnecessary and would duplicate Idaho Power’s efforts. 

Signage Plan 

The current signage at the project is inconsistent in design, and many signs are in 

need of maintenance. Idaho Power proposes to develop and implement a signage plan for 

the entire project area and on adjoining lands that it owns. 

Our Analysis 

Development and implementation of a signage plan would provide the means for 

coordinated and systematic development of signage associated with the project. The 

proposed plan could have a direct beneficial effect on recreational experiences and 

aesthetic resources at the project by improving the means of providing public 

information, as well as its availability to the public. 

3.3.7 Cultural Resources 

3.3.7.1 Affected Environment 

Section 106 of the National Historic Preservation Act 

Section 106 of the NHPA as amended requires the Commission to take into 

account the effects of licensing a hydropower project on any historic properties and allow 

the Advisory Council on Historic Preservation (Advisory Council) a reasonable 

opportunity to comment if any adverse effects to historic properties are identified within 

the hydropower project’s APE. 

Historic properties are defined as any district, site, building, structure, or object 

that is included in or eligible for inclusion in the National Register. In this document, we 

also use the term “cultural resources” to include properties that have not been evaluated 

for eligibility for listing in the National Register. In most cases, cultural resources less 

than 50 years old are not considered eligible for the National Register. Cultural resources 

need enough internal contextual integrity to be considered historic properties. For 

example, dilapidated structures or heavily disturbed archaeological sites may not have 

enough contextual integrity to be considered eligible. TCPs are a type of historic 

property that are eligible for the National Register because of their association with 

cultural practices or beliefs of a living community that: (1) are rooted in that 

community’s history; or (2) are important in maintaining the continuing cultural identity 

of the community (Parker and King, 1998). 

Section 106 also requires that the Commission seek concurrence with the SHPO 

on any finding involving effects or no effects on historic properties and allow the 

Advisory Council an opportunity to comment. If Native American properties have been 

identified, section 106 also requires that the Commission consult with interested Native 

American tribes that might attach religious or cultural significance to such properties. 
106 

If there were an adverse effect on historic properties, the applicant must develop a 

HPMP to seek to avoid, reduce, or mitigate the effects. Potential effects that may be 

associated with a hydroelectric project include any project-related effects associated with 

the day-to-day operation and maintenance of the project after issuance of a new license. 

During development of the HPMP, the applicant should consult with the Commission, 

Advisory Council, Idaho SHPO, Indian tribes, and BLM. In most cases, the HPMP 

would be implemented by execution of a PA that would be signed by the Commission, 

Advisory Council (if it chooses to participate), Idaho SHPO, and other consulting parties. 

Idaho Power proposes to implement its HPMP, dated December 2008. We discuss the 

elements of the proposed HPMP in section 3.3.7.2, Environmental Effects, Management 

of Historic Properties. 

Area of Potential Effects 

Pursuant to section 106, the Commission must take into account whether any 

historic property could be affected by the issuance of a proposed new license within a 

project’s APE. The APE is determined in consultation with the Idaho SHPO and is 

defined as the geographic area or areas within which an undertaking may directly or 

indirectly cause alterations in the character or use of historic properties, if any such 

properties exist. In this case, the APE for the Swan Falls Project includes lands within 

the project boundary, as delineated in the current FERC license, plus lands outside the 

project boundary where project operations may affect the character or use of historic 

properties and/or TCPs. 

As delineated by Idaho Power, the APE encompasses the likely extent of project 

operations and project-related environmental measures that could be undertaken during 

the term of the new license. In its application and associated HPMP, Idaho Power 

described the APE as encompassing a 23.8-mile-long section of the Snake River between 

the Guffey Railroad Bridge in Owyhee County, Idaho, and the vicinity of Castle Butte in 

Ada County, Idaho. The APE includes the Swan Falls dam and powerhouse and all of 

the Swan Falls reservoir. The upstream boundary of the APE begins on both sides of the 

river near Big Foot Bar (RM 471). From there, the APE encompasses a linear zone 

extending 160.9 meters (528 feet) inland from the high water line of the reservoir. In the 

vicinity of the dam, the APE is expanded to include the entire project boundary, 

extending as much as 500 meters (1,640 feet) inland on either side of the river. 

Downstream of the dam, a BLM access road runs above the right bank of the river. In 

this area, the APE reverts back to 160.9 meters (528 feet) on either side of the river for 

the length of this road to RM 453.4. Downstream of this point, the APE narrows to a 

width of 30.5 meters (100 feet) from the OHWM on either side of the river. The APE 

extends downstream to just past the Guffey Railroad Bridge at RM 447. 

In its response to Idaho Power’s invitation to a pre-consultation meeting, the Idaho 

SHPO did not specifically comment on the APE (letter from S. Pengilly Neitzel, Deputy 

SHPO, Idaho State Historical Society, Boise, ID, to C. Jones, Idaho Power, Boise, ID, 
107 

June 1, 2004, filed in the license application). However, the Idaho SHPO recommended 

that Idaho Power complete its proposed survey of the APE and recommended that areas 

that would be used for off-site mitigation for other resources, including fish and wildlife 

mitigation areas, also be included in the survey. In its application, Idaho Power does not 

propose any off-site mitigation areas in conjunction with the new license, and no areas 

outside of the APE as defined were surveyed. 

Cultural History Overview 

Extensive summaries of the Snake River Plain prehistory have been developed. 

Three primary cultural periods have been proposed for the region encompassing the Swan 

Falls Project area. These are the Paleo-Indian Tradition or Period (11,500–8,000 before 

present [BP]), the Archaic Tradition or Period (8,000–250 BP), and the Protohistoric 

Period (250–100 BP). The first two periods reflect changes in resource procurement 

strategies and technology from a focus on big game hunting to a more diversified 

subsistence economy. They also demonstrate adaptation from the use of large spear and 

atlatl dart points to the use of bow and arrow and pottery for storage. The Protohistoric 

Period began with the introduction of the horse and the resulting change in mobility and 

use of European material goods. The presence of worked glass, arrow points 

manufactured out of iron and brass, trade beads, and other items are testament to this 

significant cultural change. All references in this section are as cited by Corn and 

Baker (2008). 

The Paleo-Indian Tradition includes the Clovis, Folsom, and Plano subperiods. 

The Paleo-Indian tradition is generally regarded as focused on big game hunting, 

including mammoth, bison, mountain sheep, and deer, but with contributions of plant 

foods and small game as well (Butler, 1986). Radiocarbon dates suggest that the earliest 

Clovis occupations date to ca. 11,500 BP. Most Clovis components on the western Snake 

River Plain are marked by only surface finds (Reid et al., 2006). However, one site 

located north of Swan Falls contained at least three large Clovis points, two smaller 

Clovis points, and 28 bifacial blanks or cores (Titmus and Woods, 1985). This site has 

been characterized as a cache, although its actual status is not clear. 

The Folsom subperiod dates from 10,000 to 9,600 radiocarbon years BP. Only a 

single Folsom site has been excavated in the Snake River Plain. Located within a cave, 

this site contained the remains of several extinct mammals, including mammoth, bison, 

camel, and dire wolf, although only the mammoth bone has been modified as a result of 

human activity. Mammoth bone and Folsom points were both recovered from the same 

stratigraphic level, although there is no clear association between them. The Plano 

subperiod dates from 10,600 to 7,800 BP. This period is characterized by lanceolate 

points and a focus on bison hunting. Mountain sheep remains have also been found at 

higher elevation sites above the Snake River Plain. 

The Archaic Tradition includes the Early, Middle, and Late Archaic Periods. This 

period of time is characterized by a change to a wider subsistence economy and the 
108 

beginning of warmer or drier, middle Holocene climate conditions. The Early Archaic 

period dates from 8,000 to 5,000 BP and is marked by the introduction of side-notched 

dart points (Northern or Bitterroot side-notched points) and the use of lanceolate Cascade 

points. This change in technology to the use of atlatl weaponry occurs at this same time 

throughout the Great Plains, Great Basin, and Plateau. Like the Paleo-Indian Period, 

subsistence during the Early Archaic also focused on big game; however, smaller game 

such as deer, elk, rabbits, fish, birds, and reptiles were also taken. Three sites in the 

immediate vicinity of the Swan Falls Project have been dated to this period. 

The Middle Archaic Period dates from 5,000 to 2,000 BP. This period is marked 

by large, side- and corner-notched atlatl dart points. However, the presence of ground 

stone tools indicates even more diversity in subsistence. Sites dating to the Middle 

Archaic include three sites located in the western Snake River Plan. 

The Late Archaic Period dates from 2,000 to 250 BP. Adaptation to the use of 

bow and arrow and pottery, as well as increasing exploitation of resources, occurred at 

this time. The latter part of this period is marked by Rosegate and Desert side-Notched 

arrow points, and pottery has been classified as Shoshone Ware, a flat-bottomed, 

undecorated vessel. During the Late Archaic, pictographs and petroglyphs may have 

served as markers for important locations. Many Late Archaic sites have been 

documented on the Snake River Plain in the vicinity of the Swan Falls Project. 

The Protohistoric Period began with the introduction of the horse and the resulting 

change in mobility and use of European material goods. The presence of worked glass, 

brass and iron arrow points, trade beads, and other items are testament to this significant 

cultural change. 

Ethnographically, the Swan Falls area was inhabited by the Northern Shoshone 

and the Bannock peoples. Northern Shoshone traditional territory includes the Snake 

River Plain in Idaho and most of the southern half of the state. The Bannock immigrated 

to the Swan Falls area from Oregon, but lived peacefully with the Northern Shoshone. 

These two groups did not have defined territorial boundaries; loose social organization 

permitted movement between their ranges (Murphy and Murphy, 1986; Steward, 1938). 

Villages, or hamlets, were located on either side of the river. Each village was 

economically independent, with individual families undertaking their own subsistence 

pursuits. Most people spent the winters on the Snake River living on dried and stored 

fish, insects, and plant foods. Others traveled to the Camas Prairie about 250 miles north 

of the river, returning in the spring. Winter camps were kept small and generally 

consisted of approximately three families. 

While salmon were the primary focus of fishing along the Snake River, people 

also took sturgeon and trout. Following the spring salmon runs, camas, yampa root, and 

other plants were collected from the Camas Prairie. Processed camas was transported 

back to the Snake River where it was stored with other plant resources including edible 
109 

roots, serviceberries, chenopod seeds, chokecherries, and sunflowers. Inhabitants of the 

Snake River also hunted deer, bison, and a variety of small mammals. 

Beginning in 1867, the Boise and Bruneau Shoshone and some Bannock peoples 

lived on the Fort Hall Reservation near Pocatello, Idaho, about 200 miles east of the 

Swan Falls Project area. In 1868, other Shoshone and Bannock tribes entered into the 

Treaty of Fort Bridger with the United States government. This treaty extinguished some 

tribal land claims and provided a reservation at Wind River for the Eastern Band of 

Shoshones. In 1869, the Fort Hall Reservation was designated as a Bannock reservation, 

and the Bannocks joined the Boise and Bruneau Shoshone at this location. Later, the 

Lemhi Shoshone also relocated to the Fort Hall Reservation. The Fort Hall Reservation 

is now known as the Shoshone-Bannock Tribes of the Fort Hall Reservation. The Swan 

Falls area is identified by Indian Claims Commission as a “common use” area used by 

the Shoshone-Bannock, Shoshone-Paiute, and other groups.42 

The earliest Euro-Americans to visit the vicinity of the project area were American 

and British fur traders in the early nineteenth century. Between 1807 and 1810, and 

following the Lewis and Clark Expedition, the North West Company constructed several 

trading posts in Washington, Montana, British Columbia, and Idaho. To compete with 

the North West Company, John Jacob Astor’s Pacific Fur Company organized two 

expeditions to the area; one of these expeditions explored the area around Swan Falls in 

November 1811 (Rollins, 1935). 

The first trading post in southern Idaho was established by John Reed in 1813 

approximately 44 miles northwest of the western end of the Swan Falls Project area. This 

post was destroyed by local tribes within several months. That same year, the North 

West Company acquired all of the Pacific Fur Company’s assets in the Northwest. A 

supply depot, called Fort Nez Percés, was established by Donald McKenzie in 1818 near 

the confluence of the Walla Walla and Columbia rivers in southeast Washington (Ross, 

1956). This post was the base for McKenzie’s three “Snake Country Expeditions.” 

McKenzie attempted to establish another post at the location of Reed’s earlier post, but 

was not successful. 

In 1821, the British Hudson’s Bay Company merged with the North West 

Company and acquired its western posts and the “Snake Country Expeditions.” A 

permanent trading post, Fort Boise, was established in 1834 near the mouth of the Boise 

River. This post was an important stop on the Oregon Trail until it was abandoned in the 

middle 1850s (Robertson, 1999). The Snake River Plain became the primary route 

between the supply posts in the Columbia River Basin and the hunting grounds of Idaho 

and Wyoming. 

 

42 Shoshone Tribes of Indians v. United States, 11 Ind. Cl. Comm. 387, 414-415, 

434-435[1962]. 
110 

By the 1840s, the fur trade had declined and intensive settlement in the area began. 

The establishment of the Oregon Trail resulted in several hundred thousand immigrants 

traveling through southern Idaho. A southern branch of the trail passed by the vicinity of 

the project, but did not cross through the project area. 

As settlement occurred in southwestern Idaho, tension between the settlers and 

Native Americans increased. The Hudson’s Bay Company was forced to abandon its 

trading post at the mouth of the Boise River, and in 1863 a military garrison was 

established in this vicinity (Frazer, 1965 and Idaho State Historical Society, 1965). This 

new post, known as Fort Boise, was the base of operations for the Army during the 

Bannock War of 1878 and the Sheepeater campaign of 1879. Troops remained there 

until 1913 (Hart, 1963). 

In 1862, gold was discovered in the Boise Basin near Idaho City, about 60 miles 

northeast of the project area. Within 2 years, more than 16,000 people rushed to the 

Boise Basin (Battien, 1989). The Owyhee Mountains southwest of the project area began 

to see gold mining in 1863. This enterprise led to the establishment of several 

settlements in the area. This settlement activity ultimately contributed to the federal 

effort to relocate Native American groups in the vicinity of the project area and the 

beginning of the Shoshone-Bannock Tribes of the Fort Hall Reservation and the 

Shoshone-Paiute Tribes of the Duck Valley Reservation, as described above. After 1870, 

placer mining in the area declined, although some prospectors, particularly Chinese, 

remained to work along the banks of the Snake River. Small-scale mining continued 

throughout the nineteenth century and into the twentieth century. 

In the 1860s and 1870s ranching became an important industry in the area. Cattle 

and sheep were imported from California as early as 1865. In 1878, the Owyhee Cattle 

and Horse Growers’ Association (later the Owyhee Cattlemen’s Association) was 

established to protect livestock herds from thieves; by 1888 there were an estimated 

100,000 head of cattle in Owyhee County and by the turn of the century there were more 

than 150,000 head of sheep (Adams, 1979). By the 1920s, Mountain Home (about 40 

miles southeast of the project area) became one of the nation’s leading shipping depots 

for wool (Groefsema, 1949). In addition to cattle and sheep, hundreds of wild burros and 

horses also roamed the banks of the Snake River. The wild horses competed for grazing 

land, and many were captured and sold for chicken feed (Nettleton, 2006). Evidence of 

early ranching can be seen throughout the project area. 

In 1897, construction of the Boise, Nampa, and Owyhee Railroad (BN&O) began 

and the town of Guffey was established near the project area. In 1899, the town of 

Murphy was established southwest of Guffey at the terminus of the BN&O line. Murphy 

became a major freight distribution point and one of the largest livestock shipping points 

in the Pacific Northwest (Adams, 1979). 

The need for electricity at the mines around Silver City in the Owyhee Mountains 

approximately 54 miles west of the project area resulted in the construction of a 

hydroelectric plant at Swan Falls. Dam construction began in the spring of 1900 and by 
111 

December, most of the plant and the concrete portion of the dam were completed. The 

power lines connecting Dewey and Silver City and providing power to nearby towns 

were operational by 1903. Additional transmission lines were constructed in 1906. 

In 1916, Idaho Power assumed control of the dam’s operation, and major 

reconstruction of the dam occurred in 1920 and 1936. Swan Falls dam and power plant 

were listed on the National Register in 1976. 

The Swan Falls village (IHSI #010-17866) was constructed to house employees of 

the Swan Falls dam. When the village was recorded, the earliest standing structure was 

noted as being built in 1918; a cottage foundation dated prior to 1910. Most of the early 

residents of the village were single men who lived in a boarding house. The supervisor 

and chief operator lived in cottages. When it became difficult to retain a work force, 

additional cottages were constructed for workers and their families. One of the cottages 

was converted to a school. 

Following completion of Swan Falls dam, the power company constructed a small 

ferry upstream. A wagon road along the slope of the canyon led to the ferry. The ferry 

was used to deliver mail to the communities of Melba, Guffey, and Murphy but was only 

in operation for a few years. Although several other ferries operated within the project 

area during the late nineteenth and early twentieth centuries (e.g., Priest Ranch, three 

ferries at Castle Creek), this may have been the only powered ferry on the Snake River 

(Huntley, 1979). By the 1930s automobiles replaced horse-drawn stages and bridges 

were constructed to accommodate the growing number of motor vehicles. Many sections 

of the old roads alongside the river are not closed to vehicle traffic, although no motor 

vehicle bridges cross the river within the project APE. 

Previous Cultural Resources Investigations 

Idaho Power identified a regional study area extending beyond the APE and 

completed a record search of this area at the Idaho State Historical Society. The record 

search found that at least 27 different archaeological studies have been undertaken in the 

vicinity of the Swan Falls Project. These studies are discussed in terms of four general 

time periods: the 1920s to the 1970s, the 1980s, the 1990s, and the “New Millennium.” 

The first archaeological investigations near the Swan Falls Project were 

undertaken in 1929, with the work undertaken on behalf of Idaho State College (Tuohy, 

1959; Tuohy and Swanson, 1960; Swanson, 1965), Idaho State University (Keeler and 

Koko, 1971), and the Boise State College Archaeology Club (Statham, 1971). 

Additionally, in 1976, BLM surveyed a 75.2-mile stretch of the Snake River along the 

Swan Falls to Guffey reach (Murphey, 1977, 1981). These investigations led to the 

establishment of the Guffey Butte-Black Butte Archaeological District in 1978. The 

Archaeological District encompasses the entire project area and extends from near Grand 

View, Idaho, to a point approximately 30 miles downstream near Walters Ferry, Idaho. 

The Archaeological District includes 118 archaeological sites, most of which are 

associated with Native American use. 
112 

In the 1980s, additional studies were undertaken in the project vicinity by Idaho 

Archaeological Consultants (Plew, 1980), Boise State University (Ames,1982a, 1982b, 

1983), the BLM (Wyatt, 1985; Willig, 1988, 1989), and Idaho State University 

(Sammons and Myler, 1994). These studies included some of the first intensive 

archaeological studies in the area as well as the excavation of several important sites. 

In 1991, Idaho Power surveyed the area containing the historic Swan Falls village, 

where new buildings associated with the project were to be constructed (Druss, 1991). 

One site, 10AA204, was a refuse dump located in the construction zone; this dump was 

subsequently determined to be ineligible for the National Register, but an associated 

foundation and other remains were not evaluated. Deterioration of many of the historic 

structures in the Swan Falls village complex and ongoing maintenance problems led 

Idaho Power to remove many of the buildings during renovation of the housing area. 

Because the village was considered to be a historic property eligible for listing on the 

National Register, mitigation measures were developed in consultation with Idaho SHPO 

and the Commission. A cultural resources management plan was developed and then 

implemented through a memorandum of agreement. Under the memorandum of 

agreement, Idaho Power completed Historic American Building Survey documentation at 

the village. Most of the buildings were documented and reviewed in 1992 after the 

Historic American Building Survey documentation was completed (Stacy, 1992, 1996). 

Also in the early 1990s, a concentration of 83 boulders containing petroglyphs in 

the project vicinity were systematically recorded (Nance and Young, 1993). In 1995, 

Boise State University conducted an archaeological field school downstream from Swan 

Falls dam. Throughout 1996 and in 1998 (Plew, 1996; Palmgren, 1998), BLM conducted 

several surveys in the project area. This included a survey of 80 acres of land just 

downstream from Swan Falls dam and 40 acres within the Guffey-Black Butte 

Archaeological District. 

In the late 1980s, an increased demand for additional generating capacity and the 

age of the existing Swan Falls powerhouse led to a decision by Idaho Power to construct 

a new powerhouse between the historic powerhouse complex and the left bank of the 

Snake River. Once the new structure was completed, modifications were made to the 

historic powerhouse, including removal of the turbine and other historic equipment. Prior 

to decommissioning, Idaho Power sponsored Historic American Engineering Record 

(HAER) documentation of the historic powerhouse (HAER No. ID-20), which served as 

mitigation for the “adverse effect” to historic properties resulting from removal of 

historic equipment (Stacy, 1991). The HAER documentation was accepted by the NPS 

and filed with the Library of Congress with a copy sent to the Idaho SHPO. 

Since 2000, BLM has conducted additional surveys in the vicinity of the project 

(Palmgren, 2000; Shaw, 2000; 2002; 2003; Wallace, 2003). Additionally, FWS surveyed 

the mid-channel islands in the project area (Raymond, 2002). Finally, in 2005, Science 

Applications International Corporation conducted a small survey near Swan Falls dam 

(Corn and Gross, 2005). 
113 

The record search resulted in the identification of 310 previously recorded 

archaeological resources within the regional study area. Most of these resources are 

located outside of the APE. As mentioned above, one historic district (the Guffey ButteBlack Butte Archaeological District) is documented within the APE. A total of 74 of the 

historic properties listed in the district are located within the project APE. An additional 

74 sites previously recorded within the APE are not contained within the 

district boundaries. 

Identified Resources 

Prehistoric and Historic Archaeological Resources 

During summer 2006, Idaho Power conducted an intensive archaeological survey 

of all of the 3,472 acres within the APE to relocate and re-record all 148 of the previously 

recorded sites in the project APE and locate and record any resources that had not been 

previously documented. Additionally, surveyors sought to correct errors in site locations 

found on previous records. Five of the previously recorded sites that are currently listed 

in the Archaeological District could not be located during relicensing studies. An 

additional 12 previously recorded sites not listed in the Archaeological District were 

either (1) located but in poor condition, (2) not relocated, (3) not relocated and assumed 

destroyed, or (4) not accessible due to landowner constraints. 

A final report titled Archaeological Survey of the Swan Falls Project Area was 

prepared that presented the results of the fieldwork (Root et al., 2008). The survey 

resulted in the identification and recordation of 57 new sites. Including the number of 

previously recorded sites, 205 sites have been documented within the APE (Root et al., 

2008; Corn and Baker, 2008). 

A total of 148 of the 205 resources identified within the APE are prehistoric in 

nature or strictly associated with Native American use. Native American sites include 

rockshelters, open campsites, boulder shelters, housepits, lithic scatters, and rock art. 

These sites appear to span a considerable range in chronological age. Dated components 

of the sites in the Swan Falls region suggest occupation of the Snake River Plain from at 

least the Archaic Period through the Protohistoric Periods (Corn and Baker, 2008). 

Of the 57 new sites that were recorded, 28 sites contain only historic components 

(Euroamerican or Chinese). These sites include historic archaeological sites and 

structures, a bridge, ferry crossings, cabin remains, and a small town site. Another 28 

sites contain both Native American and historic components. Finally, one site was 

subsequently determined to be modern and is therefore not considered to be a site 

(10AA456). 

Table 13 provides a summary of all 205 archaeological sites and architectural 

properties identified within the project APE. 
114 

Table 13. Archaeological and historic resources within the Swan Falls Project APE 

(Source: Corn and Baker, 2008, as modified by staff). 

Evaluation or Recommendation Number Comments 

Listed in district or individually 75 Of the 75 sites, five previously 

recorded sites were not relocated 

during the relicensing survey 

(10AA19, 10AA50, 10OE25, 

10OE247, and 10OE250) 

Eligible 105 -- 

Total number of listed or eligible sites 180 -- 

Insufficient information (relocated 

and in poor condition, not relocated, 

denied access to, not relocated and 

assumed destroyed) 

12 Of 12 sites, one was located and is 

in poor condition (10AA210); 

access to two sites was denied 

(10OE2014, 10OE2015); six sites 

were not relocated (10AA22, 

10AA199, 10AA2100, 10SAA201, 

10AA208, 10OE31); the remaining 

three sites were not relocated and 

are assumed to be destroyed due to 

heavy disturbance in the reported 

location (10AA193, 10AA194, 

10AA195). 

Not eligible, as determined by the 

Idaho SHPO 

1 10AA204 

Not eligible 11 Of the 11 sites, two previously 

recorded sites were not relocated

during the relicensing survey 

(10AA186 and 10AA445) and one 

site was determined to be modern 

(10AA456). 

Unevaluated 1 Not relocated (IHSI 01-15199) 

Total Sites in APE 205 -- 

The Idaho SHPO concurred with the National Register evaluations contained 

within a draft of the archaeological report (letter from K.C. Reid, State Archaeologist and 

Deputy SHPO, Idaho State Historic Preservation Office, Boise, ID, to S. Baker, Senior 

Archaeologist, Idaho Power, Boise, ID, December 28, 2007, filed in the 

license application). 
115 

In its application, Idaho Power states that all 105 of the sites that are eligible for 

the National Register but are not currently listed in the Archaeological District could also 

contribute to the Archaeological District’s eligibility. 

Historic Structures 

Three historic period structures were documented within the project APE: the 

Swan Falls dam and its associated original powerhouse (10AA211, IHSI 01-759, IHSI 

73-759); the boardinghouse, which is the last remaining building from the operator’s 

Swan Falls Village (IHSI 01-17866); and the Guffey Railroad Bridge (10OE1994, 

10CN44, IHSI 73-1706, IHSI 73-4908). 

As mentioned above, the Swan Falls dam and powerhouse were built between 

1900 and 1901 to supply power to the Silver City area of the Owyhee Mountains. The 

dam and its associated features are listed on the National Register as components of the 

first hydroelectric project on the Snake River. 

Swan Falls Village (IHSI #010-17866) was constructed to house employees 

working at Swan Falls dam. The boardinghouse (also known as the clubhouse) was 

constructed in 1901 and was the first residence built at the dam site. The boardinghouse 

is maintained and remains in good condition. While not currently listed on the National 

Register, the structure has been recommended as eligible for inclusion. 

The Guffey Railroad Bridge is not associated with the Swan Falls Project 

facilities. It was constructed between 1896 and 1897 to support mining operations in 

Silver City. The bridge is listed on the National Register as part of the 

Archaeological District. 

Traditional Cultural Properties and Sacred Sites 

No ethnographic studies have been undertaken in the project area. The ShoshoneBannock Tribes have commented several times that an ethnographic study should be 

implemented (letter from A.A. Colby, Chairman, Fort Hall Business Council, ShoshoneBannock Tribes, to C. Jones, Idaho Power, Boise, ID, December 21, 2007; letters from 

A.A. Colby, Chairman, Fort Hall Business Council, Shoshone-Bannock Tribes, to the 

Commission, Washington, D.C., August 26, 2008, and March 13, 2009). In their most 

recent letter, the Shoshone-Bannock Tribes comment that they remain interested in 

working with Idaho Power and the Commission to implement an ethnographic study. In 

its application, Idaho Power states that the Shoshone-Bannock, Shoshone-Paiute Tribes, 

Burns Paiute Tribe, and Fort McDermit Paiute and Shoshone Tribes have not responded 

to requests for assistance in identifying any TCPs that may be located within the 

project APE. 
116 

3.3.7.2 Environmental Effects 

Effects of Project Operations on Cultural Resources 

We describe Idaho Power’s proposed operations in section 2.2.2, Proposed 

Project Operations. In this section, we evaluate the effects of Idaho Power’s proposed 

operations on the following resources: (1) prehistoric and historic-period archaeological 

resources; (2) historic buildings and structures; and (3) TCPs and sacred sites. 

Prehistoric and Historic Archaeological Resources 

Archaeological sites can be disturbed by any action (natural, animal, or human) 

that disturbs soils or ground surfaces on which they occur. Archaeological sites are 

susceptible to disturbance from grazing, pedestrian and vehicular traffic, construction, 

vandalism, and wind erosion. Fluctuating water levels can result in eroding shorelines 

and adverse effects on archaeological sites that may be located along those shorelines. 

Exposure of archaeological sediments as a result of erosion can lead to displacement or 

loss of cultural materials, and also to exposure of artifacts that may become vulnerable to 

unauthorized collecting or inadvertent damage. 

Archaeological surveys conducted by Idaho Power (Root et al., 2008) included 

assessment of site conditions and descriptions of observed disturbances at cultural 

resources sites in the Swan Falls APE. Identified disturbances varied, and included 

damage as a result of recreational activity, erosion, roads and vehicle traffic, construction, 

cattle grazing, and other activities. In its application, Idaho Power stated that adverse 

effects as a result of project operations could include shoreline erosion that is attributable 

to reservoir fluctuation and damage as a result of project road construction and 

maintenance. Idaho Power concluded that 65 of the 205 sites in the APE had signs of 

disturbance that could be attributed to project operations, with the primary agent being 

river erosion. At these sites, disturbances were evaluated as minor (33 sites), moderate 

(19 sites), moderate to severe (1 site), and severe (11 sites). One additional site was 

documented as having completely lost integrity (10OE3083). Surveyors were either 

denied access to 10 additional sites or were unable to relocate them; effects to these sites 

are therefore unknown. While many of the 130 remaining archaeological sites also 

exhibited deteriorating conditions, Idaho Power concluded that most of these 

disturbances were not related to the project. 

Of the 11 sites with severe effects, 10 were identified as being affected by a 

variety of agents (10AA54, 10AA176, 10AA177, 10AA189, 10AA448, 10AA457, 

10OE24, 10OE583, 10OE9863, and 10EL2036) with erosion being the major 

disturbance. One severely affected site (10AA41) was damaged by vandalism. Idaho 

Power recognized that at least some of the erosion observed at the archaeological sites 

within the APE may be a result of project operations. However, in its application, Idaho 

Power stated that operational conditions and restrictions ensure that the river elevation 

changes, both upsteam and downstream of the dam, are relatively gradual and of 

comparatively low magnitude. Idaho Power concludes that these gradual elevation 
117 

changes limit the degree to which project operations are responsible for erosion of 

cultural sites in river and shoreline locations. 

Only three instances were noted of road damage to sites on lands owned by Idaho 

Power or on other lands where road damage is a result of project activities (10AA41, 

10AA43, 10OE3083). Both table E.4-10 of the application and Idaho Power’s 

archaeological survey report state that road construction associated with project operation 

affects site 10AA43. This site also has been heavily vandalized. Idaho Power states that 

it does not believe it is responsible for adverse effects on sites resulting from vandalism 

(Root et al., 2008). 

Although dispersed recreation affects more than half of the sites within the project 

APE, Idaho Power stated that most of these sites are accessible because of an existing 

road; therefore, disturbances associated with recreational activities are not project related. 

However, a report titled Influences of Human Activities on Terrestrial Resources 

Associated with the Swan Falls Hydroelectric Project (human use study; Carpenter, 

2008) used a GIS predictive model to conclude that 13 sites within the APE are 

potentially at Very High, High, or Moderate risk for damage as a result of human use 

(primarily recreation) associated with the project. 

In section 3.3.1.6 of the HPMP, Idaho Power acknowledges that improvements to 

the existing six dispersed recreation sites could also affect historic properties. 

Additionally, as part of the recreation improvements and implementation of the Wildlife 

Habitat Protection and Enhancement Plan, many of the braided roads that currently 

traverse the project area would be closed and revegetated. Single access roads to the 

existing and proposed recreation improvements would encourage visitors to remain on 

designated access roads. In section E.4.1.3.3 of the application, Idaho Power explains 

that no archaeological sites or TCPs have been identified within the specific footprint of 

these planned improvements. No known archaeological sites would be affected by the 

proposed measures. 

Our Analysis 

Fluctuating water levels, even gradual changes, can destabilize soils and lead to 

seepage failure that affects not only shorelines but also archaeological materials present 

in those soils. Erosion of soils containing archaeological materials can result in 

displacement or loss of artifacts, as well as exposure of artifacts, making them vulnerable 

to unauthorized collecting or inadvertent damage. 

Continued operation of the Swan Falls Project would cause adverse effects on 

some of the identified archaeological sites within the project’s APE that are subject to 

fluctuating water levels.43 Such erosion effects caused by fluctuating water levels result 

 

43 The 3-foot fluctuation zone within the project’s reservoir and the shoreline 

downstream from the project’s dam include erosion-related effects caused by the project. 
118 

in deflation of archaeological materials through the underlying sediments, lateral 

displacement of archaeological materials, and destruction and removal of archaeological 

materials through incising, cutting, and undercutting of the bank. The primary erosion 

effects occurring at the Swan Falls Project are cutting and undercutting of soft sediments 

along the bank. Fluctuations in water levels stemming from project operations can cause 

slumping and collapsing of archaeological deposits along the shoreline where these cut 

banks occur. 

In our October 7, 2008, AIR, we requested that Idaho Power provide site-specific 

treatment measures for the sites that are severely affected by erosion. We also requested 

that Idaho Power include a statement in its response that the measures would be 

implemented upon license issuance, or that it specify how mitigation for such effects 

would be accomplished under the original license. Idaho Power responded that sites 

experiencing severe erosional effects would be monitored over 3 years to determine if 

that erosion is project related (Idaho Power, 2009a). We analyze and address erosion of 

historic properties present within the APE in Management of Historic Properties below. 

The surface visibility of many archaeological sites leaves them vulnerable to 

damage or destruction by recreational and other users. Idaho Power proposes 

improvements to the Swan Falls downstream boat ramp, Swan Falls Park, and Swan Falls 

reservoir boat ramp and improvement of six dispersed recreation sites both upstream and 

downstream of Swan Falls dam (see section 3.3.5, Recreation), which could affect 

archaeological sites. 

In its application and HPMP, Idaho Power proposes measures for monitoring and 

treating, as necessary, sites potentially subject to adverse effects from recreational use. 

We analyze and address Idaho Power’s proposed measures for the treatment of 

archaeological sites affected by recreational activity and improvement proposals in 

Management of Historic Properties below. 

Historic Buildings and Structures 

Continued maintenance, repair, and upgrades to historic buildings and structures 

associated with the Swan Falls Project are necessary to meet safety and operational needs 

and also to retain their historic character. These activities could potentially adversely 

affect these resources by altering the characteristics of the structures that may qualify 

them for inclusion in the National Register. 

The remaining historic structures associated with the project are the original 

powerhouse, Swan Falls dam, and Swan Falls Village boardinghouse. These structures 

are currently maintained by Idaho Power. One additional historic structure within the 

project APE, the Guffey Railroad Bridge, is not a project structure and it is not 

maintained by Idaho Power. In its application, Idaho Power states that any adverse 

effects to the bridge are therefore not project-related. 
119 

In its application and HPMP, Idaho Power states that it would continue to maintain 

and use Swan Falls dam, the original powerhouse, and the Swan Falls boardinghouse.44 

The HPMP contains a protocol for review of maintenance, repair, alteration, renovation, 

and restoration activities that may be necessary in the future to ensure that the historic 

character of these structures is preserved. 

Our Analysis 

Project operations could beneficially affect Swan Falls dam and the original 

powerhouse through continued use and maintenance. However, repairs and upgrades 

could also affect the characteristics of these properties that make them eligible for listing 

on the National Register. Because it is integral to the functioning of the hydroelectric 

project, the dam would remain in active use and good condition. However, the original 

powerhouse and boardinghouse are not necessary for the operation of the project and 

could become obsolete or unnecessary, potentially leaving these structures susceptible to 

deterioration or neglect. Continued use and maintenance of the dam, original 

powerhouse, and boardinghouse would increase the likelihood that these structures would 

be repaired and maintained. Idaho Power’s proposal to assess the potential for adverse 

effects associated with structure maintenance and repair and to consult the Secretary of 

the Interior’s Standards for the Treatment of Historic Properties to identify preservation 

options if adverse effects cannot be avoided would ensure that such adverse effects are 

resolved in a manner consistent with the requirements of section 106 of the NHPA. 

Traditional Cultural Properties 

In its application, Idaho Power recognized that project effects on potential TCPs 

are unknown because such resources have not yet been documented within the APE. In 

its HPMP, Idaho Power proposes to conduct a TCP study within the first 3 years after 

new license issuance. 

Our Analysis 

We analyze and address Idaho Power’s proposed measure for the future 

identification and management of TCPs below under the heading Management of 

Historic Properties. 

Management of Historic Properties 

In 2007, in consultation with BLM, the Idaho SHPO, and Shoshone-Bannock 

Tribes, Idaho Power prepared a draft HPMP to address project effects on historic 

properties. The draft HPMP and an archaeological survey report were provided to the 

Idaho SHPO for comment, and the Idaho SHPO responded in December 2007 (letter 

from K.C. Reid, State Archaeologist and Deputy SHPO, Idaho State Historic 

 

44 Although this building is currently referred to as the clubhouse, its historical use 

was as a boardinghouse. 
120 

Preservation Office, Boise, ID, to S. Baker, Senior Archaeologist, Idaho Power, Boise, 

ID, December 28, 2007, filed in the license application). Most of the Idaho SHPO’s 

comments were addressed in a revised HPMP that was provided to the Commission in 

June 2008 as part of the final license application. Commission staff commented on the 

June 2008 HPMP and the resulting response. Idaho Power filed a second revised HPMP 

with the Commission in December 2008. 

Measures contained within HPMPs typically include regular monitoring of historic 

properties and the identification of specific mitigation measures to address project-related 

effects. Regular monitoring of cultural resources is a meaningful way to assess the 

existing condition of archaeological sites and to determine if a given site’s condition has 

changed over time and why. Monitoring may indicate whether or not a project’s 

operation and/or maintenance activities are resulting in those changes and if those 

changes may adversely affect site characteristics that might make it eligible for inclusion 

on the National Register. In these cases, appropriate mitigation measures would be 

developed to eliminate or lessen the disturbance and to prevent further deterioration or 

loss of resource integrity. For archaeological resources, mitigation measures may include 

installing protective barriers or fencing, closing roads and/or redirecting activities that are 

disturbing a site, or stabilizing a site through the planting of native vegetation or 

installation of mechanical stabilization materials. For historic buildings and structures, 

repairs (when undertaken in keeping with the historic nature of the structure) or 

prevention of conditions that cause adverse effects would be appropriate. 

Monitoring 

Idaho Power proposes to implement a monitoring program that would assess site 

conditions over time, determine the cause of identified disturbances, and allow for the 

development of appropriate mitigation measures. The program identifies three 

monitoring protocols: (1) general site monitoring; (2) assessing project impacts on 

historic properties; and (3) assessing impacts on historic properties from human-use. 

According to the program, all sites within the APE would be monitored according to one 

of the protocols, except for those resources that were ineligible for the National Register, 

not related to the project (of which some are assumed destroyed through inundation or 

erosion), or not accessible because access was denied by private landowners. 

Under Idaho Power’s proposal, most of the sites within the project APE would be 

monitored according to the general site monitoring protocol. This protocol would begin 

with an initial data collection period of 4 years. During this period, Idaho Power would 

visit the sites every other year so that all sites would be visited twice over the course of 

4 years. Following this assessment period, the need for future monitoring would 

be evaluated. 

The 10 sites severely affected by erosion (10AA54, 10AA176, 10AA177, 

10AA189, 10AA448, 10AA457, 10OE24, 10OE583, 10OE9863, and 10EL2036) would 

be monitored according to the second protocol—assessment of project impacts. This 
121 

protocol would call for annual monitoring of these sites for a 3-year period. During 

monitoring, disturbances at these sites would be precisely mapped and photographed. 

After 3 years of monitoring, data would be evaluated to determine if observed damage is 

project related. Monitoring frequency would then be re-evaluated. Sites experiencing 

severe project-related adverse effects would continue to be monitored annually under this 

protocol; sites experiencing moderate project-related adverse effects would continue to be 

monitored every 3 years. All sites experiencing severe or moderate project-related 

adverse effects would also be assessed for the need to implement mitigation measures. 

Idaho Power states that this assessment could occur prior to the end of the 3-year 

monitoring period. Sites with no project-related adverse effects would be reassigned to 

the general monitoring protocol. 

The third monitoring protocol—assessing impacts from human use—would be 

applied to effects at the 13 sites identified in the human use study as potentially at Very 

High, High, or Moderate risk for damage. These sites would be monitored to test the 

human use study GIS model and to assess effects of human use. This protocol would call 

for annual monitoring of these sites for a 3-year period. During monitoring, disturbances 

at these sites would be photographed each year from the same vantage point and then 

mapped on the most recent site sketch map. After 3 years of monitoring, data would be 

evaluated to determine the interval of future monitoring or the possibility of reassigning 

specific sites to the general monitoring protocol. The data would also be used to make 

management recommendations to other appropriate landowners. However, Idaho Power 

states that it does not assume responsibility for observed effects on lands owned by others 

or costs related to the mitigation effects on those lands. Recommendations of protective 

or mitigation measures may be made prior to the end of the three-year monitoring period. 

After implementation of these three monitoring protocols, Idaho Power estimates 

(for budgeting purposes only) that monitoring could find that six sites could require some 

sort of mitigation. 

Our Analysis 

Idaho Power’s proposal to implement a general monitoring program at sites where 

the cause of site disturbance is unknown would help determine if damage is project 

related. This would in turn enable Idaho Power to assess the need for and frequency of 

future monitoring. It would also assist in the development of appropriate treatment 

measures if disturbances are identified as being related to project operations. 

In its application and HPMP, Idaho Power proposes to implement the monitoring 

protocol for assessing project impacts at the 10 sites that are experiencing severe 

erosional impacts. However, while a protocol for mapping and photographing the 

erosion at these sites over a 3-year period is identified in the HPMP, Idaho Power does 

not indicate how such monitoring would determine if the erosion that is occurring is 

project related or describe the criteria that would be used to make these determinations. 

Additionally, spending 3 years to monitor sites that are currently eroding could delay 
122 

implementing corrective measures, resulting in the continued loss of archaeological site 

integrity of significant historic properties. 

As mentioned above, Idaho Power states that no archaeological sites or TCPs have 

been identified in the specific footprint of the proposed recreational improvements. 

However, site location maps and records provided in Idaho Power’s archaeological report 

(Root et al., 2008) indicate that significant historic properties are located in the 

immediate vicinity of the improvements and/or along the access roads to these improved 

areas. These sites include, but are not limited to, the following: 10AA20, 10AA21, 

10AA41, 10AA43, 10AA45, 10AA197, 10AA205, and 10AA210. All of these sites are 

either listed or eligible for listing on the National Register, and proposed recreation 

improvements could directly affect them. In its HPMP, Idaho Power does not discuss the 

potential adverse effects associated with the proposed recreation improvements on these 

or other historic properties. Instead, Idaho Power proposes to implement the general 

monitoring program at seven out of eight of these sites, monitoring them every other year 

for 4 years. At the eighth site (10AA205), the monitoring protocol for assessing impacts 

from human-use would be implemented, and the site would be monitored annually. 

Although the closure of braided roads in the project area would provide some 

protection to historic properties currently affected by vehicle access and recreational use, 

monitoring alone would not ensure that the eight historic properties identified above are 

protected from potential adverse effects associated with proposed recreation 

improvements. Consideration of the potential direct and/or indirect effects of the 

improvements (including access roads) on historic properties in the vicinity of the 

facilities and compliance with section 106 in accordance with the protocol provided in 

section 4.8.1 of the HPMP, Review Process Prior to Ground-Disturbing Activities, would 

ensure that these properties are protected from potential adverse effects of recreational 

improvements and that appropriate treatment or mitigation is undertaken if necessary. 

Further, the timely installation of protective measures, such as road closures, barricades 

to block vehicular access to sensitive areas, and the posting of restrictive signage, would 

ensure that damage to these sites and other affected sites is lessened. In addition to the 

proposed monitoring, consultation with the Idaho SHPO to develop and implement 

specific measures addressing the direct and indirect effects on historic properties from 

proposed recreation improvements and project-related dispersed recreational activities 

would ensure compliance with section 106 of the NHPA. 

The human use study identified 13 sites that could be at risk from human use 

(Carpenter, 2008). In its response to BLM’s comments on the draft license application, 

Idaho Power stated that the human use study would “not be used as a tool or mechanism 

for monitoring, and was expected only to provide a process for identifying sites 

susceptible to a specific type of risk so that they could be monitored with that factor in 

mind.” However, in its HPMP, Idaho Power provides a specific protocol to monitor 

these 13 sites (assessment of impacts from human-use) that is not afforded to the other 

sites within the APE. Although data obtained from monitoring the 13 sites would serve 

to test the ability of the GIS model to predict potential project effects, we question the 
123 

adequacy of the study because it did not cover the entire APE and identified only one of 

the sites (10AA205) that would be potentially affected by the proposed recreation 

improvements. 

Mitigation 

In its application and HPMP, Idaho Power proposes a measure that would 

implement or recommend implementation of mitigation measures for historic properties 

that are currently adversely affected by project operations. Historic properties would be 

assigned to one of two possible mitigation categories depending on the outcome of the 

various site monitoring protocols: (1) for sites with non-project adverse effects located 

on non-Idaho Power lands, Idaho Power would recommend possible mitigation measures 

but would not be responsible for mitigation; and (2) for sites on Idaho Power lands or 

determined to be experiencing project-related adverse effects, Idaho Power would assume 

responsibility for mitigation. Idaho Power assumed that most sites that fall into the first 

category would be those subject to damage as a result of vandalism, looting, grazing, 

recreation, shoreline erosion along the river, or general erosion. Sites that fall into the 

second category would be those adversely affected by shoreline erosion along the 

reservoir as a result of water level fluctuation. 

Although it proposes no immediate mitigation measures for specific sites within 

the APE, Idaho Power identified potential mitigation measures such as restricting access, 

installing cautionary signs, conducting security patrols, data recovery excavations, and 

stabilizing shorelines. Idaho Power states that in all cases, it would strive to leave the 

existing historic properties in place. In its discussion of mitigation measures in the 

HPMP, Idaho Power reiterates that the 10 historic properties experiencing severe erosion 

potentially related to project operations would be monitored to determine if the observed 

erosion is indeed project-related. Idaho Power stated that it assumed that 6 of these 10 

sites may require some level of mitigation. 

Idaho Power’s archaeological survey report (Root et al., 2008) states that a road 

maintained by Idaho Power provides access to site 10AA43. This site has been greatly 

disturbed by vandalism and looting. The survey report therefore recommended that the 

site be tested for intact deposits (Root et al., 2008). Immediate treatment of site 10AA41 

was also recommended. However, in response to Idaho SHPO’s comments on the draft 

license application, Idaho Power states that any recommendations made by its consultants 

in the archaeological report are the opinions of the report authors and do not represent 

agreement by Idaho Power. It its application and HPMP, Idaho Power instead calls for 

general monitoring of sites 10AA41 and 10AA43 and possibly the installation of 

educational signage at a proposed new recreation facility. No other mitigation for 

vandalism is proposed. 

Our Analysis 

While natural erosion as a result of water runoff cannot be attributed to the project, 

erosion associated with the project can result in a loss of archaeological site integrity. 
124 

Kept unchecked, erosion has the potential to adversely affect significant cultural 

resources. Idaho Power does not propose to conduct any mitigation for erosional adverse 

effects until after its monitoring program has been implemented. However, according to 

the site records prepared during the archaeological survey, artifacts are eroding from 

cutbacks at all 10 of the sites experiencing severe erosion. At one site, a large hopper 

mortar was reported as “teetering” on the edge of a cutbank, and would “fall into the river 

soon” (Root et al., 2008). Because the site record for this resource is dated September 

2006, it is very possible that this artifact has been lost to the river. Additionally, cultural 

features, including a possible house floor, were reported as eroding from at least three of 

the sites, and the site record for site 10AA54 states that the site “will require immediate 

stabilization.” Idaho Power’s archaeological survey report recommends limited testing of 

nine of the sites in order to determine if intact subsurface deposits are present near 

eroding cutbanks. 

Three of the 10 sites severely affected by erosion are located on the banks of Swan 

Falls reservoir and 7 are located downstream of Swan Falls dam. While studies of 

erosion associated with operation of the C.J. Strike and Swan Falls Hydroelectric projects 

(Wulforst et. al., 2000; Holmstead and Turley, 2005) concluded that water level 

fluctuations attributable to operation of the Swan Falls Project are unlikely to cause 

significant shoreline erosion. We note, however, that these studies were essentially 

conducted in terms of how such erosion affects terrestrial resources or riparian habitat 

overall, but were not undertaken from an archaeological perspective. Archaeological 

perspectives on shoreline erosion deal with the destruction and dislocation of 

archaeological cultural deposits, features, or artifacts. In situ cultural deposits, features, 

and artifacts are critical in the preservation of archaeological sites and movements or 

alterations of such materials through shoreline erosion can effectively destroy the 

integrity of an archaeological site over time. As discussed previously, shoreline erosion 

of archaeological materials caused by project-generated fluctuating water levels, both 

upstream and downstream from Swan Falls dam, can cause such displacement and 

destruction of archaeological materials. Appropriate treatment of the 10 sites to reduce 

the effects caused by shoreline erosion would ensure that these historic properties are 

protected from further damage. If Idaho Power, in consultation with BLM and the Idaho 

SHPO, developed site-specific treatment measures for all 10 sites, which could include 

testing and/or installation of stabilization measures, it would ensure that these 

archaeological deposits are adequately protected from further erosion. This work could 

be accomplished now under the existing license or could be implemented under a revised 

HPMP upon issuance of a new license. 

Similarly, if Idaho Power, in consultation with the Idaho SHPO and other agencies 

as appropriate, developed and implemented specific testing and/or mitigation measures 

for sites 10AA41, 10AA43, and all other sites that are experiencing vandalism on Idaho 

Power lands, it would ensure that these sites are protected. This work could be 

undertaken under the conditions of the existing license to ensure that the sites are 
125 

protected as soon as possible, or addressed through a revised HPMP that would be 

implemented upon license issuance. 

Identification of Traditional Cultural Properties 

Idaho Power’s HPMP provides a plan to identify TCPs through consultation with 

the Shoshone-Bannock Tribes, the Shoshone-Paiute Tribes of the Duck Valley 

Reservation, the Burns Paiute Tribe of the Burns Colony, and the Fort McDermitt Paiute 

and Shoshone Tribes. Any TCPs that are identified and are eligible for the National 

Register would merit the same treatment measures as those identified in the HPMP for 

other known historic properties. Appropriate measures to address project-related adverse 

effects to areas of traditional use that are eligible for the National Register would be 

developed in consultation with the Idaho SHPO, agencies, and tribes. 

In March, 2009, the Shoshone-Bannock Tribes provided comments in response to 

project scoping documents (letter from N. Small, Vice-Chairman, Fort Hall Business 

Council, Shoshone-Bannock Tribes, to the Commission, Washington, DC, filed with the 

Commission March 13, 2009). In their letter, the Tribes requested the Commission to 

require a broader National Environmental Policy Act analysis of the APE that would 

result in an analysis that would encompass the Tribal perspective of project effects. The 

Shoshone-Bannock Tribes also commented that they consider the Snake River to be 

eligible for the National Register as a TCP and recommended the Commission analyze 

mitigation measures to promote the recovery of native species within the project area. 

Further, the Shoshone-Bannock Tribes expressed concern regarding potential adverse 

effects to the environment as a result of proposed flow changes, and requested increased 

monitoring and development of site protection measures for National Register eligible 

resources. Finally, the Shoshone-Bannock Tribes commented that they are interested in 

working with the Commission and Idaho Power to implement an ethnographic study for 

the project. They noted that while a complete copy of study results would be provided to 

Commission (subject to confidentiality restrictions), only summary reports of the 

resulting data would be provided to Idaho Power. 

Our Analysis 

The Swan Falls Project has the potential to adversely affect TCPs that may be 

present within the APE. Idaho Power’s proposal to implement a TCP study and to 

continue consultation with the participating tribes would ensure that such properties are 

documented and potential project-related adverse effects are addressed The ShoshoneBannock Tribes suggest that mitigation measures should be analyzed that would promote 

the recovery of native species within the project area. The completion of a TCP study 

would assist in the identification of areas that are currently being used to gather plants for 

traditional purposes. Such areas might be TCPs, and appropriate mitigation for project 

effects to these areas could include revegetation of native plant species. 
126 

Other Management of Historic Properties 

Idaho Power’s HPMP includes a variety of other measures for management of 

cultural resources and implementation of the HPMP: 

• Appointment of an historic properties management coordinator responsible for 

overseeing implementation of the HPMP. 

• Annual reporting to agencies and tribes on activities associated with the HPMP 

that were undertaken during the preceding year. 

• As-needed training sessions for Idaho Power staff (beginning in the first year 

of HPMP implementation) to ensure that employees are familiar with cultural 

resource laws and regulations, instruction on HPMP protocols and 

requirements, and other information necessary regarding historic properties. 

Idaho Power states that the Idaho SHPO, BLM, and affected tribes can be 

invited to periodically attend the training sessions and assist in instruction if 

they desire. 

• Pre-action review by the HPMP coordinator of planned actions involving 

ground disturbance in consultation with the Idaho SHPO, appropriate tribes, 

and appropriate land management agencies as specified in the HPMP. 

• Development of a public interpretation program that provides information 

concerning the cultural history of the project area. This program includes (1) 

improving interpretive and education displays at the Swan Falls powerhouse 

museum and increasing days and hours of public access; and (2) developing 

interpretive and educational displays at the Swan Falls dam and 

boardinghouse. 

• Implementation of specific protocols specified in the HPMP in the event of 

emergency situations or the inadvertent discovery of a previously unknown 

cultural resource or human remains. 

• A plan to conduct additional analysis of archaeological materials previously 

recovered from the project area. 

• A requirement that persons undertaking any archaeological excavations that 

may be necessary for the project meet the Secretary of the Interior’s Standards 

for Professional Archaeologists and hold necessary state and federal permits, 

including curation agreements for recovered materials. 

No additional historic properties management measures were recommended by 

agencies and tribes in response to the Commission’s REA notice and request 

for comments. 

Our Analysis 

Idaho Power’s proposal to appoint a historic properties management coordinator 

with local knowledge of the project’s cultural resources, familiarity with applicable state 
127 

and federal laws and regulations, and professional experience in cultural resources 

management would ensure that the requirements of the HPMP are followed. Annual 

reporting to agencies and affected tribes on the status of overall cultural resources 

management over the course of the year would provide a regularly scheduled forum for 

parties to discuss the HPMP and provide recommendations about management of cultural 

resources. While the HPMP does not call for a formal review and/or revision of the 

HPMP, such a review process undertaken every 5 years would provide a sound basis for 

implementation of the HPMP over the license term. Affording the BLM the opportunity 

to comment, along with the Idaho SHPO and tribes, on proposed revisions to the HPMP 

would ensure that federal agencies with interest in the management of cultural resources 

on or adjacent to their lands would be able to contribute their views. 

Idaho Power’s proposal to conduct training sessions as needed for staff involved 

with the public or involved in planning and implementation of actions potentially 

affecting significant cultural resources would ensure that new employees are educated in 

a timely manner. These sessions would also ensure that all employees are regularly 

informed about issues, procedures and protocols regarding cultural resource management 

in the project. Inviting the participation of a tribal representative at each training session 

would contribute toward staff understanding of Native American perspectives on 

cultural resources. 

Idaho Power’s implementation of review procedures during the planning of 

potential ground-disturbing activities, as well as protocols for inadvertent discovery of 

previously unknown cultural resources and human remains as specified in its HPMP, 

would ensure that significant cultural resources are not inadvertently harmed by projectrelated actions, and that resources and human remains would be appropriately treated. 

Idaho Power’s proposals to install interpretive signage regarding cultural resources 

and their significance, and to increase days and hours of public access at Swan Falls 

powerhouse museum, would enable the public to become aware of the cultural 

importance of the project area. This could lead to an enhanced visitor experience and 

encourage protection of resources. The inclusion on the signs of information pertaining 

to site protection and applicable laws would provide an effective vehicle for educating 

the public about vandalism, its effects, and its potential legal consequences. 

Idaho Power’s proposal to develop and implement guidelines for curation of 

archaeological materials recovered at the project that are in accordance with federal and 

state requirements would ensure that such materials are properly conserved and also 

accessible, under properly controlled conditions, to those with appropriate research or 

cultural interests. 

As discussed above, development and implementation of site-specific 

management measures for the 10 archaeological sites subject to severe adverse effects as 

a result of erosion would protect these sites from further damage. Additionally, 

development of measures to address potential adverse effects on archaeological sites that 

may be affected by proposed recreation improvements and road closure/revegetation 
128 

activities associated with the Recreation Plan and the Wildlife Habitat Protection and 

Enhancement Plan would ensure that these resources are appropriately preserved. 

Finally, identification and implementation of measures to address severe adverse effects 

occurring on archaeological sites caused by looting and vandalism would ensure that 

these sites are protected from these damaging activities. 

Revision of Idaho Power’s December 2008 HPMP to include these measures, 

following consultation with the involved parties, would ensure protection of historic 

properties within the project APE in accordance with section 106. 

3.3.8 Socioeconomics 

3.3.8.1 Affected Environment 

The Swan Falls Project is located in Ada and Owyhee counties, Idaho. The city of 

Boise is the most populated city within Ada County, with an estimated population of 

198,638 in 2006 (U.S. Bureau of the Census, 2009d). Table 14 presents population and 

other demographic data for the Ada and Owyhee counties and for Idaho from the U.S. 

Bureau of the Census. 

Table 14. Population characteristics of Ada County, Owyhee County, and Idaho 

(Source: U.S. Bureau of the Census, 2009a,c). 

Population, 

2000

Population 

Estimate, 

2008 

Private 

Nonfarm 

Employment, 

2006 

Median 

Household 

Income, 

2007 

Persons Below 

Poverty Level, 

2007 (percent) 

Ada 

County 

300,904 380,920 187,342 $55,121 7.9 

Owyhee 

County 

10,644 10,877 1,630 $35,683 17.5 

Idaho 1,293,955 1,523,816 546,251 $46,136 12.1 

The U.S. Census Bureau reports that in 2000 there were approximately 285.2 

persons per square mile in Ada County, 1.4 persons per square mile in Owyhee County, 

and 15.6 persons per square mile in Idaho as a whole. Population increases between 

2000 and 2008 have followed the same pattern, with Ada County showing the highest 

growth at 26.6 percent, Owyhee County the lowest growth at 2.2 percent, and Idaho an 

intermediate growth at 17.8 percent (U.S. Bureau of the Census, 2009a, 2009c). The 

growth of the Ada County population is due to the presence of Boise, the state capital, 

and other fast growing cities such as Meridian, while the very slow growth in Owyhee 

County can be accounted for by the remoteness of most of the county from population 

centers. According to the data shown in table 14, the same pattern also prevails in 
129 

median household incomes, with Ada County highest at $55,121, Owyhee County lowest 

at $35,683, and Idaho at an intermediate point ($46,136). 

The U.S. Bureau of the Census (2000) reports that the top three industries in the 

state in terms of employment were educational, health, and human services 

(19.2 percent); manufacturing (13.1 percent); and retail trade (12.6 percent). Ada 

County, which includes the metropolitan area of Boise, followed the same pattern with 

the top three industries being educational, health, and human services (17.4 percent); 

manufacturing (14.3 percent); and retail trade (12.7 percent). Rural Owyhee County had 

a very different pattern of employment, with the top three sectors being agriculture, 

forestry, fishing and hunting, and mining (25.5 percent); educational, health, and human 

services (13.7 percent); and manufacturing (14.8 percent). In Owyhee County, retail 

trade accounted for 7.3 percent of employment in 2000. 

3.3.8.2 Environmental Effects 

The Swan Falls Project benefits the local economy by providing a reliable source 

of power and by providing recreational opportunities that would not otherwise be 

available nearby. Idaho Power has not proposed any measures specifically associated 

with socioeconomic resources. 

Our Analysis 

Continued operation of the project as proposed by Idaho Power would continue to 

provide an economical source of power to the region, helping to support future economic 

growth. The additional spending associated with implementing various resource 

measures, such as the rehabilitation of degraded vegetation and the improvement of 

developed and dispersed recreational areas, would provide for some additional 

employment during the period of construction and monitoring. 

3.4 NO-ACTION ALTERNATIVE 

Under the no-action alternative, the project would continue to operate as it has in 

the past. None of Idaho Power’s proposed measures or the resource agencies’ 

recommendations and mandatory conditions would be required. Water quality and other 

aquatic conditions would remain essentially the same, with the minimum flow remaining 

the same as under current conditions. Riparian and upland habitats would not be 

rehabilitated, but would continue to be adversely affected by dispersed recreation use. 

Cultural resources would continue to be subjected to erosion, vandalism, and recreational 

use that cause site deterioration. Proposed upgrades to recreational sites would not occur. 
130 

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131 

4.0 DEVELOPMENTAL ANALYSIS 

In this section, we look at the Swan Falls Project’s use of the Snake River for 

hydropower purposes to see what effect various environmental measures would have on 

the project’s costs and power benefits. Consistent with the Commission’s approach to 

economic analysis, the power benefit of the project is determined by estimating the cost 

of obtaining the same amount of energy and capacity using the likely alternative 

generating resources available in the region. In keeping with Commission policy as 

described in Mead, our economic analysis is based on current electric power cost 

conditions and does not consider future escalation of fuel prices in valuing the 

hydropower project’s power benefits.45

Our analysis includes: (1) an estimate of the cost of individual measures 

considered for the protection, mitigation and enhancement of environmental resources 

affected by the project, and (2) an estimate of the project power benefits for each of the 

licensing alternatives. To determine the net annual power benefit for each of the 

licensing alternatives, we compare project costs to the value of the power output as 

represented by the cost of a likely alternative source of power in the region. For any 

alternative, a positive net annual power benefit indicates that the project power costs 

less than the current cost of alternative generation resources and a negative net annual 

power benefit indicates that project power costs more than the current cost of alternative 

generation resources. This estimate helps to support an informed decision concerning 

what is in the public interest with respect to a proposed license. However, project 

economics is only one of many public interest factors the Commission considers in 

determining whether, and under what conditions, to issue a license. 

4.1 POWER AND ECONOMIC BENEFITS OF THE PROJECT 

Table 15 summarizes the economic assumptions and economic information we 

use in our analysis. This information was provided by Idaho Power in its license 

application. We find that the values provided by Idaho Power are reasonable for the 

purposes of our analysis. Cost items common to all alternatives include taxes and 

insurance costs; net investment (the total investment in power plant facilities remaining 

to be depreciated); estimated future capital investment required to maintain and extend 

the life of plant equipment and facilities; relicensing costs; normal operation and 

maintenance cost; and Commission fees. 

 

45 See Mead Corporation, Publishing Paper Division, 72 FERC ¶ 61,027 (July 

13, 1995). In most cases, electricity from hydropower would displace some form of 

fossil-fueled generation, in which fuel cost is the largest component of the cost of 

electricity production. 
132 

Table 15. Parameters for the economic analysis of the Swan Falls Project. 

Assumption Value Source 

Period of economic analysis 

(years) 

30 Staff 

Current net investment 

(2010 dollars)a

$44,400,000 Idaho Power (2008a) 

Current annual costs 

including operation and 

maintenance, FERC fees, 

and taxes (2010 dollars)b

$657,000 Idaho Power (2008a) 

Relicense Application Costsc

 $10,700,000 Idaho Power (2008a) 

Term of financing (years) 20 Staff 

Cost of capital (percent)d 8.18 Ida-Corp 10-K report 

Discount rate (percent)e

 7.16 Idaho Power (2008a) 

Energy rate ($/MWh)f

On-Peak 

(Heavy Load) 

Off-Peak 

(Light Load) Idaho Power (2009a) 

January 62.50 52.98 

February 59.33 48.94 

March 53.68 44.90 

April 46.07 33.23 

May 40.26 26.04 

June 38.18 26.94 

July 63.92 42.21 

August 70.72 51.64 

September 69.36 50.29 

October 62.40 50.74 

November 55.00 45.00 

December 65.00 55.50 

Composite rate (annual) g 50.12 Staff 

Capacity rate 

($/kilowatt-year)h

154 Energy Information 

Administration 

Note: MWh – megawatt-hour 
133 

a

 Net investment provided in Exhibit D.2.2 of the license application. 

b

 Annual costs were derived from Exhibit D, table D-2 of the license application. 

c Cost to develop the license application is included in the current net investment total 

of $44,400,000. 

d

 The cost of capital was based on the weighted average cost of capital as provided on 

page 22 of Ida-Corp’s Form 10-K filing to the Securities and Exchange Commission 

for fiscal year ending December 31, 2008. 

e

 The discount rate was provided in Exhibit D.4 of the license application. 

f

 The energy rates were provided by Idaho Power in its January 5, 2009, AIR response 

4 (Idaho Power, 2009a). The rates refer to Mid-Columbia Forward Values for 

November 2008 through October 2009. 

g The composite energy rate is estimated based on a ratio of an on-peak energy time of 

7:00 a.m. to 11:00 p.m. Monday thru Friday, and an off-peak energy time of 11:00 

p.m. to 7:00 a.m. Monday thru Friday, and all day Saturdays, Sundays, and holidays. 

h

 The capacity rate is based on the Energy Information Administration’s Annual 

Outlook for 2009 at http://www.eis.doe.gov/oiaf/aeo/index.html. 

4.2 COMPARISON OF ALTERNATIVES 

Table 16 compares the annual costs and annual power benefits for the three 

alternatives considered in this draft EIS: no action, Idaho Power’s proposal, and the 

staff alternative. 

4.2.1 No-action Alternative 

Under the no-action alternative, the project would continue to operate as it does 

now. The project generates an average of 161,300 MWh of electricity annually. The 

annual power value of the project under the no-action alternative would be $9,239,350 

(about $57.28/MWh). The average annual cost of producing this power would be about 

$7,117,920 (about $44.13/MWh), resulting in an average annual power benefit of 

$2,121,430 (about $13.15/MWh). In other words, the project produces energy at a cost 

that is less expensive than that of currently available alternative generation by 

$13.15/MWh. 

4.2.2 Idaho Power’s Proposal 

Under Idaho Power proposal, the project would continue to generate an average 

of 161,300 MWh of electricity annually. The annual power value of the project under 

Idaho Power’s proposal would be $9,239,350 (about $57.28/MWh). The average 

annual cost of producing this power would be about $7,667,520 (about $47.54/MWh), 

resulting in an average annual cost of $1,571,830 (about $9.74/MWh) less expensive 

than the likely alternative cost of power. 
134 

Table 16. Summary of annual costs and annual power benefits for the alternatives 

for the Swan Falls Hydroelectric Project (Source: staff). 

 No Action 

Idaho Power’s 

Proposal 

Staff 

Alternative 

Installed capacity (MW) 25 25 25 

Dependable Capacity (MW) 7.5 7.5 7.5 

Annual generation (MWh) 161,300 161,300 161,300 

Annual power valuea

 

($/MWh) 

$9,239,350 

57.28 

$9,239,350 

57.28 

$9,239,350 

57.28 

Annual costs 

($/MWh) 

$7,117,920 

44.13 

$7,667,520 

47.54 

$7,678,220 

47.60 

Power benefit (i.e., power 

value minus costs) 

($/MWh) 

$2,121,430 

13.15 

$1,571,830 

9.74 

$1,561,130 

9.68 

Note: MW – megawatt 

 MWh – megawatt-hour 

a

 The power value of $57.28/MWh includes the energy rate of $50.12/MWh and the 

dependable capacity rate of $154/kilowatt-year. 

4.2.3 Staff Alternative 

The staff alternative includes Idaho Power’s proposal and has the same capacity 

and energy attributes. Table 17 shows the staff recommended additions, deletions, and 

modifications to Idaho Power’s proposed environmental protection and enhancement 

measures and the estimated cost of each. The project would continue to generate an 

average of 161,300 MWh of electricity annually. The annual power value of the project 

under the staff alternative would be $9,239,350 (about $57.28/MWh). The average 

annual cost of producing this power would be about $7,678,220 (about $47.60/MWh), 

resulting in an average annual cost of $1,561,130 (about $9.68/MWh) less expensive 

than the likely alternative cost of power. The staff alternative would reduce the power 

benefit by about $10,700 (about $0.06/MWh) compared to the project as proposed by 

Idaho Power. 

4.3 COST OF ENVIRONMENTAL MEASURES 

Table 17 shows the costs for each of the environmental mitigation and 

enhancement measures considered in the analysis. We convert all costs to equal annual 

(levelized) values over a 30-year period of analysis to give a uniform basis for 

comparing the benefits of a measure to its cost. 
135 

Table 17. Cost of environmental mitigation and enhancement measures considered in assessing the e

effects of continuing to operate the Swan Falls Hydroelectric Project (Source: Staff). 

Enhancement/Mitigation Measures Entities 

Capital Cost 

(2010$)a

Annual 

Cost 

(2010$)a

Aquatic Resource Measures 1. Provide an instantaneous minimum flow of 3,900 cfs downstream of the dam from April 1 to October 31 and 5,600 cfs from November 1 to March 31 

Idaho Power, Staff $0 $0b 

2. Continue ramping rate restrictions of no more than 1 foot per hour and 3 feet per day 

Idaho Power, Staff $0 $0c 

3. Continue to remove and dispose of aquatic macrophytes and debris that accumulate on the project trash racks to remove nutrients and oxygen-demanding material from the river 

Idaho Power, Staff $0 $0c 

4. Monitor water temperature and DO in the project outflow 

Idaho Power, Idaho DEQ, 

Staff 

$25,760 $5,150 

5. Develop and implement a plan to monitor water temperature and DO at the project inflow, and monitor flow and TDG at both the project inflow and outflow, for the first 5 years after license issuance as stipulated in the 401 WQC 

Idaho DEQ, Staff $30,000 $3,340d 
136 

Enhancement/Mitigation Measures Entities 

Capital Cost 

(2010$)a

Annual 

Cost 

(2010$)a

6. Implement resident fish population monitoring 

Idaho Power $0 $1,250 

Terrestrial Resource Measures

1. Implement the proposed Wildlife Habitat and Enhancement Plan 

a. Protect, enhance, and restore 25.1 acres of riparian habitat 

Idaho Power, Idaho DFG, 

Staff 

$18,810 $63,170 

b. Protect, enhance, and restore 45.3 acres of upland habitat 

Idaho Power, Idaho DFG, 

Staff 

$0 $31,140 

2. Implement the proposed Noxious Weed Management Plan to control noxious and undesirable weed species 

Idaho Power, Staff $0 $13,220 

3. Implement Special Status Plant Management Plan to protect and monitor special-status plant species 

Idaho Power, Staff $0 $9,820 

4. Develop and implement a transmission line operation and maintenance plan 

Idaho Power $0 $0 

5. Implement timing restrictions on transmission line maintenance activities, as needed, to protect benchland nesters and cliff-nesting raptors 

Staff $0 $0 
137 

Enhancement/Mitigation Measures Entities 

Capital Cost 

(2010$)a

Annual 

Cost 

(2010$)a

6. Consider and mitigate impacts on Deer Flat National Wildlife Refuge islands located downstream of the current Swan Falls Project boundary 

FWS $0 $0e 

Recreation Resource Measures

1. Finalize and implement the draft Recreation Management Plan 

a. Continue operation and maintenance of Swan Falls Park, Swan Falls reservoir boat ramp, Swan Falls downstream boat launch, the canoe portage trail and Swan Falls powerhouse museum 

Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$0 $0c 

b. Enhance the Swan Falls reservoir boat ramp 

Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$111,510 $8,090 

c. Improve Swan Falls Park Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$125,450 $71,240 

d. Enhance the Swan Falls downstream boat launch 

Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$139,400 $8,090 

e. Improve the canoe portage trail Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$0 $4,120 

f. Enhance six dispersed recreation sitesf

Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$385,160 $24,290 
138 

Enhancement/Mitigation Measures Entities 

Capital Cost 

(2010$)a

Annual 

Cost 

(2010$)a

g. Implement the Litter and Sanitation Plan 

Idaho Power, Idaho DPR, 

Idaho DFG 

$99,580 $39,510 

h. Implement the Litter and Sanitation Plan on project lands only 

Staff $0 $0 

i. Finalize and implement the Interpretation and Education Plan 

Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$85,690 $2,030 

2. Continue implementation of the Public Safety Plan

Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$0 $0c 

3. Establish interagency recreation resource working group that convenes every 6 years 

Idaho DPR, Staff $0 $0h 

Land Use and Aesthetic Resource Measures1. Implement the Visual Guidelines Plan Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$0 $3,090 

a. Modify colors of the five Idaho Power-owned project houses 

Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$0 $720 

b. Paint the wooden elements at KOP 2 

Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$0 $220 

c. Establish screening around the laydown yard Idaho Power, Idaho DPR, Idaho DFG, Staff $28,840 $640 
139 

Enhancement/Mitigation Measures Entities 

Capital Cost 

(2010$)a

Annual 

Cost 

(2010$)a

d. Ensure that any new construction considers the protection of visual resources from important viewpoints. 

Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$0 $0 

2. Revise the Visual Guidelines Plan to include more specific details on color schemes, screenings, and materials 

Idaho DPR, Staff $0 $0 

3. Develop and implement a consistent signage plan 

Idaho Power, Staff $26,110 $0 

4. Finalize and implement a Resource Management Plan 

Idaho Power, Idaho DPR, 

Idaho DFG, Staff 

$69,240 $10,300 

5. Continue implementation policies for permitting piers, boat docks, and other facilities 

Idaho Power, Staff $0 $0c 

6. Establish interagency land use and aesthetic working groups that convene every 6 years 

Idaho DPR $0 $0h 
140 

Enhancement/Mitigation Measures Entities 

Capital Cost 

(2010$)a

Annual 

Cost 

(2010$)a

Cultural Resource Measures1. Implement the Final HPMP 

a. Conduct general site monitoring of historic properties under the December 2008 HPMP 

Idaho Power, Staff $0 $25,800 

b. Conduct site monitoring to assess impacts from human use to historic properties under the December 2008 HPMP 

Idaho Power, Staff $0 $6,290 

c. Conduct site monitoring to assess project impacts on historic properties under the December 2008 HPMP 

Idaho Power $0 $16,360 

d. Mitigate adverse impacts on six historic properties under the December 2008 HPMP 

Idaho Power $0 $15,170 

e. Consult with BLM, participating tribes, and Idaho SHPO and revise the HPMP to address mitigation of adverse impacts on at least 10 historic properties 

Staff $500,000 i $0 

f. Identify and protect TCPs under the December 2008 HPMP 

Idaho Power, Staff $0 $3,000 
141 

Enhancement/Mitigation Measures Entities 

Capital Cost 

(2010$)a

Annual 

Cost 

(2010$)a

g. Preserve the historic boardinghouse under the December 2008 HPMP 

Idaho Power, Staff $0 $4,610 

h. Conduct photo documentation and site relocation under the December 2008 HPMP 

Idaho Power, Staff $0 $1,680 

i. Conduct comprehensive recording of Site 10AA684 under the December 2008 HPMP 

Idaho Power, Staff $0 $890 

j. Analyze and publish previously collected materials under the December 2008 HPMP 

Idaho Power, Staff $0 $1,490 

k. Provide a Native American interpretative display under the December 2008 HPMP 

Idaho Power, Staff $8,240 $950 

l. Provide Swan Falls dam and boarding house interpretation and education panels under the December 2008 HPMP 

Idaho Power, Staff $14,900 $720 

m. Improve powerhouse interpretive displays under the December 2008 HPMPj

Idaho Power, Staff $17,390 $70 

n. Open the old powerhouse to seasonal public visitation under the December 2008 HPMPj

Idaho Power, Staff $0 $8,240 
142 

a Unless otherwise indicated, costs are based on values provided by Idaho Power, and were escalated t

necessary. Capital costs were adjusted in some cases depending on the year in which the cost would 

b Idaho Power estimated that implementing these proposed minimum flows would have essentially no 

generation. Based on our independent judgment of their supporting information, we concur that thereffect on generation. 

c No additional cost. The costs associated with the measures are either included in an ongoing program 

included in the annual operation and maintenance cost of the project. 

d Cost estimated by staff. The annual cost of $3,340 is estimated based on a cost of $10,000 per year fe Because this recommendation was not specific as to what would be required, we did not estimate a p

implementation. 

f Idaho Power and Idaho DFG agree on the proposal to enhance the six dispersed recreation sites. The 

would include consultation with Idaho SHPO to alleviate conflicts with cultural resources. We anticwould be similar to what Idaho Power proposes. 

g No additional costs to implement the plan only within the project boundary. h We did not estimate a potential cost for implementation of this measure. i The $500,000 capital cost is based on mitigation of the 10 sites subject to severe erosion and site 10A

sites being affected by vandalism), as well as mitigation associated with proposed recreation develop

estimates a cost of $50,000 per site. We assume that mitigation would be completed within 3 years. 

j Cultural resource measures “m” and “n” are also identified in the draft Recreation Management Plan

costs are included here, and not in the Recreation Management Plan. 
143 

5.0 CONCLUSIONS AND RECOMMENDATIONS 

5.1 COMPARISON OF ALTERNATIVES 

In this section, we compare the developmental and non-developmental effects of 

Idaho Power’s proposal, the staff alternative, and the no-action alternative. Our analysis 

shows that annual generation would be 106,300 MWh under each of the 

three alternatives. 

We summarize the environmental effects of the different alternatives below. 

Geology and Soils 

Under Idaho Power’s proposal and the staff alternative, Idaho Power would 

reduce erosion by restoring approximately 79 acres of land and 2.7 miles of riparian 

shoreline, formalizing recreational access and use areas, and eliminating informal 

recreational access and use in areas where Idaho Power proposes additional 

resource protection. 

Aquatic Resources 

Under Idaho Power’s proposal, continued removal of aquatic vegetation and 

debris that accumulates on the trash racks would remove nutrients from the river, 

helping to improve water quality, and monitoring of water temperature and DO in the 

project tailrace would help to confirm that project operations, including proposed 

minimum flow release changes, would not adversely affect short- or long-term 

water quality. 

Under the staff alternative, monitoring discharge, water temperature, DO and 

TDG of the project inflow and outflow would have the benefits of Idaho Power’s 

proposal but would also help better define any project effects on water quality over a 

range of hydrologic and meteorological conditions, and would help to determine 

whether any additional measures are warranted to address project effects on 

water resources. 

Under Idaho Power’s proposal, implementation of a resident fish population 

monitoring program would determine basic population characteristics. However, 

because the proposed monitoring is not designed to detect for the effects of any specific 

project-related action, the monitoring program is not included in the staff alternative. 

Terrestrial Resources 

Implementation of Idaho Power’s proposed Wildlife Habitat Protection and 

Enhancement Plan would improve conditions for numerous wildlife species in the 

project area that use riparian habitat and would also improve conditions in project area 

uplands. Idaho Power’s proposed Special Status Plant Management Plan would provide 

an effective means of protecting these species from recreational activity where they 

occur within the project boundary. Implementation of Idaho Power’s Noxious Weed 
144 

Management Plan would promote native plant communities that provide higher quality 

habitat for wildlife than those dominated by invasive non-native species. 

However, measures to protect soils and botanical resources in both a 

transmission line operation and maintenance plan and the Noxious Weed Management 

Plan would be duplicative, and implementation of the Noxious Weed Management Plan 

alone would ensure the protection of soils and botanical resources on all project lands, 

including the transmission line right-of-way. Therefore, under the staff alternative a 

transmission line operation and maintenance plan would not be necessary. Instead, the 

staff alternative would include timing restrictions on transmission line maintenance 

activities to minimize the risk of disturbing benchland nesters and cliff-nesting raptors 

during the breeding season. 

Threatened and Endangered Species 

Under both Idaho Power’s proposal and the staff alternative, effects on the 

federally listed endangered Snake River physa from stranding and desiccation due to 

changes in water levels would continue to be very low. 

Recreation 

Under Idaho Power’s proposal, recreational opportunities would be improved as 

a result of finalizing and implementing the draft Recreation Management Plan, which 

includes continuing operations, maintaining and upgrading the existing five project 

recreational facilities, continuing implementation of Idaho Power’s public safety 

program, improving six dispersed recreation sites, adding to interpretive and 

informational displays, and implementing the Litter and Sanitation Plan at areas both 

inside and outside the project boundary. 

Under the staff alternative, staff’s recommendation for the revision of the 

Recreation Management Plan to include additional staff recommendations and 

consultation with the Idaho DPR, Idaho DFG, Idaho SHPO, and BLM would ensure that 

the potential adverse effects of recreational development and use on cultural and 

terrestrial resources would be appropriately considered. Additionally, implementation 

of the Litter and Sanitation Plan would apply only to lands within the project boundary. 

Land Use and Aesthetics 

Under both Idaho Power’s proposal and the staff alternative, there would be a 

reduction of 599 acres within the project boundary. The proposed project boundary 

modifications would remove 791 acres of project land upstream of the Swan Falls dam 

that are not needed for project purposes, and add 192 acres of land downstream of the 

dam to incorporate restored lands as part of the Wildlife Habitat Protection and 

Enhancement Plan, cultural resource sites requiring long-term monitoring, and 

dispersed recreation sites proposed for improvement.
145 

Idaho Power’s proposal would provide some protection to visual resources under 

the provisions of the Visual Guidelines Plan. The staff alternative includes additional 

recommendations and coordination with BLM and Idaho DPR.

Cultural Resources 

Under Idaho Power’s proposal, cultural resources would be protected under 

provisions specified in the HPMP filed with the Commission in December 2008. 

However, the December 2008 HPMP does not address mitigating the effects on the 10 

archaeological sites subject to severe erosion, archaeological sites that would be 

affected by proposed recreation improvements to existing dispersed recreation sites and 

associated access roads (including closure/revegetation of other dispersed sites and 

roads), and other archaeological sites on Idaho Power lands that are being disturbed by 

vandalism and looting associated with recreational use. 

Under the staff alternative, revision of the HPMP to address these project-related 

effects would ensure that all existing and potential future adverse effects on historic 

properties would be adequately addressed over the term of any new license. The 

revised HPMP would be filed with the Commission prior to license issuance, and upon 

license issuance the revised HPMP would be implemented through execution of a PA 

for a new license. 

Socioeconomics 

Idaho Power’s proposal and the staff alternative would provide essentially the 

same socioeconomic benefits as under current conditions. 

Under the no-action alternative, environmental conditions would remain the 

same and no enhancement of environmental resources would occur. 

5.2 COMPREHENSIVE DEVELOPMENT AND RECOMMENDED 

ALTERNATIVE 

Sections 4(e) and 10(a)(1) of the FPA require the Commission to give equal 

consideration to the power development purposes and to the purposes of energy 

conservation; the protection, mitigation of damage to, and enhancement of fish and 

wildlife; the protection of recreational opportunities; and the preservation of other 

aspects of environmental quality. Any license issued shall be such as in the 

Commission’s judgment will be best adapted to a comprehensive plan for improving or 

developing a waterway or waterways for all beneficial public uses. This section 

contains the basis for, and a summary of, our recommendations for relicensing the Swan 

Falls Project. We weigh the costs and benefits of our recommended alternative against 

other proposed measures. 

Based on our independent review of agency and public comments filed on this 

project and our review of the environmental and economic effects of the proposed 
146 

project and its alternatives, we selected the staff alternative as the preferred option. We 

recommend this option because: (1) issuance of a new hydropower license by the 

Commission would allow Idaho Power to operate the project as an economically 

beneficial and dependable source of electrical energy for its customers; (2) the 25 MW 

of electric energy generated from a renewable resource may offset the use of fossilfueled, steam-electric generating plants, thereby conserving nonrenewable resources and 

reducing atmospheric pollution; (3) the public benefits of this alternative would exceed 

those of the no-action alternative; and (4) the recommended measures would protect and 

enhance fish, wildlife, land use and aesthetic, and cultural resources, and would provide 

improved recreation opportunities at the project. 

In the following section, we make recommendations as to which environmental 

measures proposed by Idaho Power or recommended by agencies and other entities 

should be included in any license issued for the project. Additionally, we discuss staffdeveloped measures that we recommend be included in any license issued for the 

project. We also discuss those measures that we do not recommend be included as 

conditions of any new license. 

Measures Proposed by Idaho Power 

Based on our environmental analysis of Idaho Power’s proposal discussed in 

section 3 and the costs discussed in section 4, we recommend including the following 

environmental measures proposed by Idaho Power in any license issued for the project. 

Our recommended modifications to Idaho Power’s proposed measures are shown 

in italics. 

Aquatic Resources 

• Provide an instantaneous minimum flow of 3,900 cfs downstream of the dam 

from April 1 to October 31, and 5,600 cfs from November 1 to March 31. 

• Monitor water temperature and DO in the project’s outflow between June 15 

and October 5 of each license year. This measure is modified to comply with 

the requirements of the WQC.

• Continue the ramping rate restrictions of no more than 1 foot per hour and 3 

feet per day. 

• Continue to remove and dispose of aquatic macrophytes and debris that 

accumulate on the project trash racks to remove nutrients and oxygendemanding material from the river. 

Terrestrial Resources 

• Implement the Wildlife Habitat and Enhancement Plan to protect, enhance, 

and restore upland and riparian habitat on applicant-owned lands within the 

project boundary, including closing nine dispersed recreation sites. 
147 

• Implement the Noxious Weed Management Plan to control noxious and 

undesirable weed species on applicant-owned lands and cooperatively46

manage noxious and undesirable species on other lands within the project 

boundary. 

• Implement the Special Status Plant Management Plan to protect and monitor 

special status plant species on applicant-owned and other lands within the 

project boundary. 

Recreation Resources 

• Finalize and implement the draft Recreation Management Plan. This measure 

is modified to include additional staff measures as discussed in the next 

subsection. 

 Continue operation and maintenance of five existing project recreation 

sites: Swan Falls Park, Swan Falls reservoir boat ramp, Swan Falls 

downstream boat launch, the canoe portage trail, and Swan Falls 

powerhouse museum. 

 Enhance the Swan Falls reservoir boat ramp by upgrading the boat 

ramp, adding a vault toilet, and enhancing parking for vehicles and 

trailers. 

 Improve Swan Falls Park by providing riprap or a retaining wall along 

the shoreline, and adding a new dock, picnic tables, and a shelter. 

 Enhance the Swan Falls downstream boat launch by constructing a twolane boat ramp, adding a vault toilet, enhancing parking for vehicles and 

trailers, and removing the air compressor. 

 Improve the canoe portage trail by installing signage. 

 Enhance six existing dispersed recreation sites located either within or 

near the project boundary (the sites outside the current project boundary 

are proposed to be brought within the new project boundary) that 

provide access to the reservoir and river. 

 Implement the Litter and Sanitation Plan, including additional vault 

toilets and dumpsters, as well as biannual litter pickups and a carryin/carry-out policy within the project boundary and outside of the 

project boundary (downstream to RM 453.4

 

46 We interpret “cooperatively” to mean in consultation with the other 

landowners. 
148 

 Finalize and implement the Interpretation and Education Plan to 

coordinate with the HPMP and provide consistency for project-related 

information. 

 Continue implementation of the applicant’s Public Safety Plan, dated 

June 2008. 

Land Use and Aesthetic Resources 

• Implement the proposed Visual Guidelines Plan. This measure is modified to 

include more specific details as discussed in the next subsection. 

 Modify the colors of the five Idaho Power-owned project houses to 

blend with soils and vegetation. 

 Paint the wooden elements associated with BLM’s KOP 2, which is the 

parking and restroom area near the powerhouse. 

 Establish screening around the lay-down yard. 

 Ensure that any new construction considers the protection of visual 

resources from important viewpoints. 

• Develop and implement a consistent signage plan for the entire project area 

and adjoining applicant-owned lands. 

• Finalize and implement the Resource Management Plan to guide Idaho Power 

staff in its hydroelectric operations and maintenance of the Swan Falls 

Project, including project-related measures to protect cultural and natural 

resources. 

• Continue implementation of policies for permitting piers, boat docks, and 

other facilities (non-project use of project lands and waters). 

Cultural Resources 

• Implement the project’s December 2008 HPMP. This measure is modified to 

implement a revised HPMP that includes more specific details as discussed in 

the next subsection. 

Additional Measures Recommended by Staff 

In addition to Idaho Power’s proposed measures listed above, we recommend 

including the following staff-recommended measures in any license issued for the Swan 

Falls Project: 

Aquatic Resources 

• Develop and implement a plan with provisions to monitor the following water 

quality parameters as stipulated in Idaho DEQ's WQC: (1) water temperature 
149 

and DO in the project’s outflow throughout the term of any issued license; (2) 

water temperature and DO in the project's inflow for at least 5 years after 

issuance of any license; and (3) TDG and discharge in the project's inflow 

and outflow for at least 5 years after issuance of any license. Develop a 

quality assurance control plan; submit annual data reports to Idaho DEQ and 

the Commission; and prepare and file a report with the Commission with a 

copy to Idaho DEQ summarizing the results of the first 5 years of monitoring, 

and describing any proposed changes to the monitoring program. 

Terrestrial Resources 

• Implement timing restrictions on transmission line maintenance activities, as 

needed, to protect benchland nesters and cliff-nesting raptors. 

Recreation Resources 

• Revise and implement the Recreation Management Plan to include: (1) 

completion of Idaho Power’s consultation with Idaho SHPO to ensure that 

work planned at the informal dispersed sites and associated access roads 

consider the effects on cultural resources known to exist in the area; (2) soil 

erosion control measures; (3) detailed design drawings of Swan Falls Park, 

Swan Falls reservoir boat ramp, Swan Falls downstream boat launch, and the 

canoe portage trail; (4) a description of improvements to the six dispersed 

recreation sites; (5) a discussion on how the needs of the disabled were 

considered in the planning and design of the recreation facilities; (6) an 

implementation schedule; (7) modification of the Litter and Sanitation Plan so 

that it applies only to lands within the project boundary; and (8) finalization 

and implementation of the Interpretation and Education Plan as part of the 

Recreation Management Plan in consultation with BLM, Idaho DPR, and 

Idaho SHPO. 

• Establish an interagency recreation working group that convenes every 6 

years in coordination with preparation of the FERC Form 80 to assess 

recreation facilities, dispersed recreation sites, and usage. 

Land Use and Aesthetic Resources 

• Revise the proposed Visual Guidelines Plan to include a list of neutral paint 

color schemes, a list of vegetation species planned for use, a list of 

construction materials that could be used, and documentation of consultation 

with BLM and Idaho DPR. 

Cultural Resources 

• Revise the December 2008 HPMP to include a program for immediate 

implementation of mitigation measures for sites being affected by shoreline 
150 

erosion or vandalism, as well as sites proposed for recreation improvements. 

Include consultation among Idaho Power, Idaho SHPO, BLM, and 

participating tribes to formulate site-specific mitigation measures. The 

anticipated PA would incorporate the HPMP. 

Following is a discussion of the basis for the additional staffrecommended measures. 

Water Quality Monitoring 

Idaho Power proposes to monitor water temperature and DO in the outflow from 

Swan Falls dam from June 15 through October 5, with data summarized for reporting on 

a monthly basis. In its WQC, Idaho DEQ specifies that Idaho Power develop a 

monitoring plan approved by Idaho DEQ, including quality control provisions, to 

monitor discharge, DO, TDG, and water temperature in the inflow and outflow from the 

project. Idaho Power would be required to submit annual data reports to Idaho DEQ, 

and after 5 years of monitoring could request the termination of some or all of the 

monitoring components, except for the monitoring of water temperature and DO in the 

outflow, and associated reporting of the results. 

As discussed in section 3.3.2, Idaho Power’s monitoring studies indicate that 

numeric standards for temperature, DO, and TDG were exceeded at times. Monitoring 

flow, water temperature, DO, and TDG in the project’s inflow and outflow over a 

5-year period as specified in the WQC, and seasonal monitoring of water temperature 

and DO in the project’s outflow from June 15 through October 5 of each license year 

thereafter, would provide information that would help determine the effectiveness of 

and macroalgae removal in conjunction with other measures being implemented in the 

Snake River Basin to improve water quality conditions; this also would confirm that 

proposed changes in project operations would not cause adverse effects on water 

quality, including water temperature, DO, and TDG. Inclusion of information on 

project inflows and outflows in monitoring reports during the first 5 years of license 

issuance should not add any cost, because Idaho Power already monitors outflows from 

the Swan Falls and C.J. Strike projects, and no substantial inflows occur between the 

two projects. We estimate that the annualized cost of the water quality monitoring 

proposed by Idaho Power with the additional monitoring provisions stipulated in Idaho 

DEQ’s WQC would be about $16,610 or about $7,710 more than just the monitoring 

components proposed by Idaho DEQ. As discussed in section 5.1, the additional 

monitoring provisions specified by Idaho DEQ would provide more comprehensive 

information on project effects on water quality. We conclude that this additional benefit 
151 

warrants the additional cost of $7,710 for implementing the monitoring components 

specified by Idaho DEQ.47

Terrestrial Resources 

As discussed in section 3.3.3.2, we agree that measures are needed to protect 

wildlife resources at and near the transmission line. Implementation of timing 

restrictions for maintenance activities could minimize the risk of disturbing benchland 

nesters and cliff-nesting raptors within or adjacent to the transmission line right-of-way. 

Idaho Power stated in its application that it anticipates that only routine maintenance 

activities would occur at the project, and that it is unlikely that it would need to conduct 

any major maintenance activities. Routine maintenance activities could be easily 

scheduled to avoid bird nesting periods. For this reason, we conclude that there would 

be no costs associated with the timing restrictions. Therefore, we recommend that any 

license issued for the project include a provision to implement timing restrictions on 

transmission line maintenance activities, as needed, to protect benchland nesters and 

cliff-nesting raptors. 

Recreation Management Plan 

As discussed in section 3.3.5.2, several dispersed recreational sites are located 

within and adjacent to the project boundary. Their proximity to known historic 

properties suggests that improvement to these sites and recreational use should be 

managed to avoid adverse effects on affected archaeological sites. Including a 

provision in the license for Idaho Power to consult with the Idaho SHPO during 

development and implementation of a final Recreation Management Plan would ensure 

that operation and maintenance of all project-related recreation measures, including 

recommended measures at the six dispersed recreation sites, would take into account 

any archaeological sites that may be affected by recreation activities. Such a provision 

in the plan would have no additional cost, and therefore, we recommend the 

consultation provision. 

We recommend that Idaho Power revise the Recreation Management Plan to 

include more specific details, as previously discussed. In addition, we recommend 

Idaho Power implement the Litter and Sanitation Plan on project lands only. For these 

staff modifications, we conclude that there would be no additional costs. 

 

47 We do note, however, that we are not adopting, as part of the staff alternative, 

the specific language in the 401 WQC that disallows Idaho Power from recommending 

any changes to its proposal to seasonally monitor water temperature and DO in the 

project’s outflow. Adopting such language would essentially predetermine the outcome 

of the need to amend any new license issued for the project. 
152 

The applicant proposes to finalize and implement an Interpretation and Education 

Plan as part of its Recreation Management Plan. The plan would include provisions to 

install displays at the project that would contain information regarding boating safety, 

sites and environmental resources of interest in the area, and the project’s canoe portage 

trail. Consultation with federal and state agencies with interests in the management of 

environmental resources in the project boundary would allow these agencies to assist 

Idaho Power with the final wording of the displays to ensure that visitors to the project 

are provided with important safety and project information. A provision to consult with 

these agencies would have no additional cost; therefore, we recommend that Idaho 

Power finalize the Interpretation and Education Plan in consultation with BLM, Idaho 

DPR, and Idaho SHPO. 

Recreation Work Group 

Idaho DPR recommends that an interagency recreation working group be 

established that would convene every 6 years to review FERC Form 80 information. 

Idaho DPR also recommends that it be designated a member of the recreation working 

group. As discussed in section 3.3.5.2, Idaho Power’s draft Recreation Management 

Plan does not provide a framework for the continued monitoring of recreation facilities, 

dispersed recreation sites, and usage. Recreational use monitoring and assessment of 

recreation-related effects on lands within the project boundary as a component of 

gathering data for FERC Form 80 and as part of the Recreation Management Plan 

would allow Idaho Power and stakeholders to consider measures to address recreational 

use, including project dispersed recreation use, over the term of the new license. 

Inviting BLM, Idaho DFG, and the Idaho SHPO to also become members of the 

working group would assist Idaho Power and the Commission at identifying any future 

recreational needs at the project. The cost associated with establishing and convening an 

interagency recreation working group once every 6 years and filing a report with the 

Commission on the consultation efforts, would be minimal. Therefore, we recommend 

that a provision be included in any new license for establishing an interagency 

recreation working group that includes Idaho Power, Idaho DPR, BLM, Idaho DFG, and 

Idaho SHPO and convenes every 6 years in coordination with preparation of the FERC 

Form 80 to assess recreation facilities, dispersed recreation sites, and usage. 

Visual Guidelines Plan 

Idaho Power proposes to implement its Visual Guidelines Plan to ensure that any 

new project construction considers the protection of visual resources from important 

viewpoints. In general, Idaho DPR supports the plan; however, Idaho DPR states that 

specific approaches are not addressed concerning material colors for structures or plant 

species used for vegetative planting. Idaho DPR recommends the development of 

aesthetic guidelines for building structures and vegetative planting at the recreation 

facilities and in the employee housing area. 
153 

Idaho DPR’s recommendation for Idaho Power to include specific approaches 

concerning material colors for structures and plant species used for vegetative planting, 

along with consultation with Idaho DPR, would help ensure that project changes would 

have minimal effects on visual resources in the project area. In addition, because of the 

proximity of BLM lands, it would be beneficial if BLM were added to this consultation 

process. As discussed in section 3.3.6.2, we recommend that Idaho Power include the 

following specific elements in its Visual Guidelines Plan: 

• A list of neutral paint color schemes identified in consultation with BLM and 

Idaho DPR to be used on new project structures. 

• A list of vegetation species identified in consultation with BLM and Idaho 

DPR for vegetative planting and/or aesthetic screening purposes. 

• A list of the construction materials identified in consultation with Idaho DPR 

and BLM that could be used for maintaining existing buildings or for new 

building construction. 

Implementation of the above provisions would provide greater specificity to the 

plan and would add no additional cost to the plan. 

Cultural Resources Management 

Continued operation of the Swan Falls Project without adequate protection 

measures could adversely affect properties that are eligible for listing on the National 

Register. Idaho Power filed an HPMP with its license application in June 2008 for the 

purpose of protecting and interpreting historic properties. The HPMP was revised again 

in December 2008. 

We find that the HPMP adequately identifies the APE, describes the cultural 

resources inventories that were conducted within the APE, and indentifies existing 

disturbances to historic properties. The HPMP also provides procedures for handling 

unanticipated discoveries and the proper treatment of human remains and sacred 

objects, if they are encountered. The HPMP provides protocols for emergency 

undertakings, periodic reporting and meetings, and appropriate review of the HPMP 

based upon changing conditions over the period of a new license. However, our review 

of the HPMP reveals that it does not provide enough site-specific measures to ensure 

that project-related adverse effects on historic properties resulting from operation, 

maintenance, recreational, or other activities would be adequately addressed over the 

term of a new license. 

Our analysis in section 3.3.7.2 found that erosion associated with the operation of 

the project is severely affecting at least 10 archaeological sites that are eligible for or 

currently listed on the National Register. Additionally, we found that implementation of 

proposed recreation improvements would affect historic properties and that an 

assessment of those effects in accordance with NHPA section 106 and implementation 

of appropriate treatment measures is necessary. Finally, significant sites located on 
154 

lands owned by Idaho Power are being affected by vandalism and looting as a result of 

their proximity to formal project recreation facilities, project-related dispersed 

recreation areas, and/or roads maintained by Idaho Power. 

The December 2008 HPMP does not adequately address these project-related 

effects. For these reasons, we conclude that the HPMP should be revised in 

consultation with BLM, participating tribes, and Idaho SHPO to include the following 

additional measures: 

• Specific treatment measures to mitigate the 10 archaeological sites identified 

by Idaho Power that are subject to severe erosion. 

• Specific measures to assess and mitigate as necessary any adverse effects of 

proposed recreation improvements on archaeological sites. 

• Measures to protect or mitigate archaeological sites that are being affected by 

vandalism and looting associated with recreational activities on Idaho Power 

lands. 

Revision of the HPMP with staff’s additional measures and subsequent 

implementation of the revised HPMP would ensure that adverse effects on historic 

properties as a result of project operation, maintenance, recreational, or other projectrelated activities would be addressed over the term of the new license. The final PA 

executed among the Commission, the Idaho SHPO, and the Advisory Council, should 

the Council choose to participate, would require Idaho power to implement a revised 

HPMP. Idaho Power, BLM, and the tribes would be invited to sign the PA as 

concurring parties. 

We estimate that implementation of the protective measures proposed in Idaho 

Power’s HPMP would have a levelized annual cost of $91,170. In addition to that cost, 

we estimate another $35,780 to address our recommended measures for a total levelized 

annual cost of $126,950. Considering the extent of cultural heritage that is present in 

the project APE, we consider the benefits to cultural resources to be worth the costs. 

Measures Not Recommended by Staff 

Staff finds that some of the measures proposed by Idaho Power or recommended 

by other interested parties would not contribute to the best comprehensive use of the 

Snake River resources or do not exhibit a sufficient relationship to project 

environmental effects. The following presents the basis for staff’s conclusions not to 

recommend such measures. 

Resident Fish Monitoring 

Idaho Power proposes to monitor the population of resident fish species in Swan 

Falls reservoir and in a 15-mile reach downstream from Swan Falls dam. Sampling 

would be conducted in the spring and fall every 5 years using boat-mounted 

electrofishing gear. Basic population characteristics, such as abundance, condition, and 
155 

proportional stock density would be assessed. Idaho DFG recommends implementation 

of this measure. 

As discussed in section 3.3.2, Aquatic Resources, although the monitoring 

information could be useful to the decision-making process of federal and state resource 

agencies charged with general fisheries management in the project area, the proposed 

monitoring is not designed to detect the effects of any specific project action, such as 

operations or maintenance, on project area fishery resources, and therefore, would be 

too broad to be of any project benefit. Moreover, we conclude that resident fish 

monitoring, even if tied to project actions, would be of little benefit because proposed 

project operations would improve the project area fishery by reducing daily variations in 

habitat for all fish species lifestages in the project area. We base this finding on already 

existing site-specific information on the relationships between project operations and 

fish habitat, negating the need for any additional monitoring or study. Therefore, we 

find that the proposed resident fish monitoring is not worth the estimated annualized 

project cost of $1,250. 

Transmission Line Operation and Maintenance Plan 

Idaho Power proposes to develop and implement a transmission line operation 

and maintenance plan for the project’s transmission line, the Swan Falls Tap, to 

eliminate or minimize potential impacts on botanical and wildlife resources that could 

result during project maintenance activities. Idaho Power also proposes specific 

management measures related to soils and botanical resources for the transmission line 

and associated right-of-way that would be included in the Noxious Weed Management 

Plan, such as weed monitoring and treatment, erosion control, and special status plant 

protection. Our analysis indicates that measures to protect soils and botanical resources 

in both a transmission line operation and maintenance plan and a Noxious Weed 

Management Plan would be duplicative, and that implementation of a Noxious Weed 

Management Plan only would ensure the protection of soils and botanical resources on 

all project lands, including the transmission line right-of-way. 

Litter and Sanitation Plan 

The applicant proposes to implement its Litter and Sanitation Plan on lands 

downstream of the Swan Falls dam to RM 453.4, which is 2 miles beyond the proposed 

project boundary at RM 455.4. As discussed in section 3.3.5.2, implementing the plan 

beyond RM 453.4 to RM 455.4 would benefit BLM lands and recreationists using those 

lands; however, recreational use of the BLM lands in this area is not related to the 

project. Therefore, we have no justification for requiring implementation of the Litter 

and Sanitation Plan beyond RM 453.4. We recommend that Idaho Power modify its 

Litter and Sanitation Plan, an element of the draft Recreation Management Plan, so that 

it applies only to lands within the project boundary. 
156 

Land Use and Aesthetics 

We do not include in the staff alternative Idaho DPR’s recommendations to 

establish both an interagency land use and aesthetic working group that would convene 

every 6 years to review FERC Form 80 information and make recommendations 

concerning future management. 

We are recommending that Idaho Power convene a recreation working group for 

the purpose of reviewing and assisting Idaho Power in the preparation of the FERC 

Form 80. This working group would consist of Idaho Power and federal and state 

resource agencies, including Idaho DPR. Establishment of separate land use and 

aesthetic working groups in addition to the recreation working group would be 

unnecessary and would duplicate Idaho Power’s efforts, and therefore, we have no 

justification for recommending a license requirement for Idaho Power to establish 

separate land use and aesthetic working groups. 

Cultural Resources 

We do not include Idaho Power’s proposed measure to conduct site monitoring 

to assess project impacts on historic properties, since we have determined that there are 

at least 10 National Register-eligible archaeological sites where adverse effects related 

to the project (i.e., principally shoreline erosion) have already been identified. We also 

did not include Idaho Power’s proposed measure to mitigate adverse effects on only 6 

historic properties, since we have identified at least 10 sites that need mitigation for 

adverse effects, and that Idaho Power needs to consult further with the SHPO, BLM, 

and involved tribes to determine the particular measures that would be underaken to 

resolve any identified adverse effects. 

5.3 UNAVOIDABLE ADVERSE EFFECTS 

Aquatic Resources 

Minor effects of the impoundment on water quality and some entrainment 

mortality of fish would continue to occur, and reservoir and tailwater levels would 

continue to fluctuate, exposing some aquatic biota to fluctuating habitat conditions.

Terrestrial 

Implementation of both the Wildlife Habitat Protection and Enhancement Plan 

and the Recreation Management Plan would help to reduce the impacts of dispersed 

recreation use on upland and riparian habitats. However, some unauthorized 

recreational activities (e.g., development of informal roads, illegal shooting) would 

continue to affect terrestrial habitat and associated wildlife. 
157 

Cultural Resources 

Improvements to the Swan Falls downstream boat ramp, Swan Falls Park, and 

Swan Falls reservoir boat ramp and enhancements to six dispersed recreation sites both 

upstream and downstream of the Swan Falls dam could affect archaeological sites. 

Project operation would also result in some continued unavoidable erosion of specific 

historic properties present on the shorelines of the reservoir and downstream portions of 

the river. 

5.4 FISH AND WILDLIFE AGENCY RECOMMENDATIONS 

Under the provisions of section 10(j) of the FPA, each hydroelectric license 

issued by the Commission shall include conditions based on recommendations provided 

by federal and state fish and wildlife agencies for the protection, mitigation, and 

enhancement of fish and wildlife resources affected by the project. 

Section 10(j) of the FPA states that whenever the Commission believes that any 

fish and wildlife agency recommendation is inconsistent with the purposes and the 

requirements of the FPA or other applicable law, the Commission and the agency will 

attempt to resolve any such inconsistency, giving due weight to the recommendations, 

expertise, and statutory responsibilities of such agency. In response to our REA notice, 

Idaho DFG submitted recommendations on August 14, 2009, for the Swan Falls Project. 

Table 18 lists agency recommendations filed subject to section 10(j) and 

indicates whether the recommendations are adopted under the staff alternative. 

Environmental recommendations that we consider outside the scope of section 10(j) 

have been considered under section 10(a) of the FPA and are addressed in the specific 

resource sections of this document and the previous section. 

We include in the staff alternative the single recommendation that we consider to 

be within the scope of section 10(j). The Commission staff makes a preliminary 

determination that two recommendations by Idaho DFG may be inconsistent with the 

purpose and requirements of the FPA or other applicable law. Table 18 indicates the 

basis for our preliminary determinations concerning the measures that we consider 

inconsistent with section 10(j). 
158 

Table 18. Fish and wildlife agency recommendations for the Swan Falls Hydroelectric Project (Sour

Recommendation Agency 

Within the Scope of Section 

10(j) 

Annual 

Cost 

Clarify plans for White Sturgeon Management Plan implementation a 

Idaho DFG Nob 0 No. The 

provide c

to a pr

conside

Canyon 

relice

rather t

Pro

Monitor the population of resident fish species in Swan Falls reservoir and in a 15-mile reach downstream from Swan Falls dam 

Idaho DFG No. Not a specific measure 

to protect, mitigate, or 

enhance fish and wildlife 

resources. Although the 

population monitoring would 

periodically occur over the 

life of the license at and near 

the project, the data that 

would be acquired would be 

too broad to specifically 

relate to the project or 

project effects. 

$1,250 No. 

monitor

to detec

specific 

as operat

In additi

suffici

assess 

between 

and fish

project-a

theref

monitor

benefit 

thes
159 

Recommendation Agency 

Within the Scope of Section 

10(j) 

Annual 

Cost 

Make license term consistent with terms set for the Hells Canyon Complex and C.J. Strike projects 

Idaho DFG No. Not a specific measure 

to protect, mitigate, or 

enhance fish and wildlife 

resources. 

0 Con

appropr

typically 

orde

environ

Implement Idaho Power’s proposed measures and implementation schedule to protect, enhance and restore riparian and upland habitat. 

Idaho DFG Yes 0c 

a As part of its section 10(j) recommendations, Idaho DFG commented on Idaho Power’s “Evaluation 

Upstream and Downstream Fish Passage at Swan Falls Dam” included as Appendix E.3.1-C of the li

and agreed with Idaho Power’s evaluation that “structural fish passage is not needed at the project at DFG instead stated that it “agrees” with the evaluation’s proposal to initiate a sturgeon capture and tr

which we interpret to be the capture and transport (“translocation”) element of the White Sturgeon C

b Measures are recommended for a plan proposed for implementation under any new license for the H

Hydroelectric Project, and therefore lack sufficient relationship to the Swan Falls Project.

c No incremental cost for this item compared to applicant’s proposal. 
160 

5.5 CONSISTENCY WITH COMPREHENSIVE PLANS 

Section 10(a)(2)(A) of the FPA, 16 U.S.C.§803(a)(2)(A), requires the 

Commission to consider the extent to which a project is consistent with the federal or 

state comprehensive plans for improving, developing, or conserving a waterway or 

waterways affected by the project. Under section 10(a)(2)(A), federal and state 

agencies filed 37 plans that address various resources in Idaho. Of these, we identified 

and reviewed 15 comprehensive plans that are relevant to the Swan Falls Project. No 

conflicts were found. 

Bureau of Land Management. 1988. Cascade resource management plan. Department 

of the Interior. Boise, Idaho. July 1, 1988. 

Bureau of Land Management. Forest Service. 1991. Snake River final 

activity/operations plan. Department of the Interior, Idaho Falls, Idaho. 

Department of Agriculture, Idaho Falls, Idaho. February 1991. 

Idaho Department of Fish and Game. 2007. Fisheries management plan, 2007-2012. 

Boise, Idaho. 2007. 

Idaho Department of Fish and Game. 2008. Management Plan for the Conservation of 

Snake River White Sturgeon in Idaho. September, 2008. 

Idaho Department of Fish and Game. Bonneville Power Administration. 1986. Pacific 

Northwest rivers study. Final report: Idaho. Boise, Idaho. 

Idaho Department of Fish and Game. 2005. Idaho Comprehensive Wildlife 

Conservation Strategy. Boise, Idaho. September 2005. 

Idaho Department of Health and Welfare. 1992. Idaho water quality standards and 

wastewater treatment requirements. Boise, Idaho. January 1992. 

Idaho Department of Parks and Recreation. Idaho Statewide Comprehensive Outdoor 

Recreation Plan (SCORP) 2003-2007. Boise, Idaho. 

Idaho Water Resource Board. 1992. Idaho State water plan. Boise, Idaho. 

January 1992. 

National Park Service. 1982. The nationwide rivers inventory. Department of the 

Interior, Washington, DC. January 1982. 

Northwest Power and Conservation Council. 2005. The fifth northwest electric power 

and conservation plan. Portland, Oregon. Council Document 2005-07. 
161 

Northwest Power and Conservation Council. 2003. Mainstem amendments to the 

Columbia River Basin fish and wildlife program. Portland, Oregon. Council 

Document 2003-11. 

Northwest Power and Conservation Council. 2000. Columbia River Basin fish and 

wildlife program. Portland, Oregon. Council Document 2000-19. 

Northwest Power and Conservation Council. 1988. Protected areas amendments and 

response to comments. Portland, Oregon. Council Document 88-22 (September 

14, 1988). 

U.S. Fish and Wildlife Service. Undated. Fisheries USA: the recreational fisheries 

policy of the U.S. Fish and Wildlife Service. Washington, DC. 
162 

This page intentionally left blank. 
163 

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Tuohy, D.R. and E.H. Swanson. 1960. Excavations at rockshelter 10AA15, southwest 

Idaho. Tebiwa 3(1):20–24. (not seen, as cited by Corn and Baker, 2008) 

Tyrer, S.J., A.M. Holthuijzen, and S.M. Vistine-Amdor. 2009. Responses to FERC 

additional information request 9: Special Status Plant Management Plan. 

Revised Final Report. Swan Falls Project, FERC No. 503. May 2009. 

U.S. Bureau of the Census. 2009a. Ada County QuickFacts from the U.S. Census 

Bureau. Available at: http://quickfacts.census.gov/qfd/states/16/16001.html. 

Accessed November 14, 2009. 

U.S. Bureau of the Census. 2009b. Canyon County QuickFacts from the U.S. Census 

Bureau. Available at: http://quickfacts.census.gov/qfd/states/16/16027.html. 

Accessed November 14, 2009. 

U.S. Bureau of the Census. 2009c. Owyhee County QuickFacts from the U.S. Census 

Bureau. Available at: http://quickfacts.census.gov/qfd/states/16/16073.html. 

Accessed November 14, 2009. 

U.S. Bureau of the Census. 2009d. Boise City (city) QuickFacts from the U.S. Census 

Bureau. Available at: http://quickfacts.census.gov/qfd/states/16/1608830.html. 

Accessed November 14, 2009. 

U.S. Bureau of the Census. 2000 Quick Tables – American FactFinder. DP-3, profile 

of selected economic characteristics, 2000. Available at: 

http://factfinder.census.gov/servlet/QTTable?_bm=y&-context=qt&-

qr_name=DEC_2000_SF3_U_DP3&-ds_name=DEC_2000_SF3_U&-

tree_id=403&-redoLog=true&-all_geo_types=N&-_caller=geoselect&-

geo_id=04000US16&-geo_id=05000US16001&-geo_id=05000US16073&-

search_results=01000US&-format=&-_lang=en. Accessed November 15, 2009. 

USGS (U.S. Geological Survey). 2009. USGS water data for the nation. Available at: 

(http://waterdata.usgs.gov). Accessed October 29, 2009. U.S. Geological 

Survey. 

USGS. 1996. Effects of military training and fire in the Snake River Birds of Prey 

National Conservation Area. Bureau of Land Management/Idaho Army National 

Guard research project. Final Report. U.S. Department of the Interior, 

Geological Survey, Biological Research Division, Snake River Field Station, 

Boise, ID. 

Vistine-Amdor, S.M., A.M. Holthuijzen and S.J. Tyrer. 2009. Responses to FERC 

additional information request 8: Noxious weed management plan. Revised 

Final Report. Swan Falls Project, FERC No. 503. May 2009. 
173 

Wallace, B. 2003. Guffey F345 emergency fire rehabilitation-Idaho. BLM report 03-)-

18. Idaho SHPO report 2003/369. Bureau of Land Management, Boise, ID. 

(not seen, as cited by Corn and Baker, 2008) 

Willig, J.A. 1988. Early to Late Archaic terrace occupation in the Snake River Birds of 

Prey Area. Paper presented at the 21st Great Basin Anthropological Conference 

Symposium, Park City, UT. Bureau of Land Management, Boise District Office, 

Boise, ID. (not seen, as cited by Corn and Baker, 2008) 

Willig, J.A. 1989. Report of test excavations and mitigation proposals at five 

archaeological sites along Halverson Road in the Snake River Birds of Prey 

Area, southwestern Idaho. Bureau of Land Management, Boise District, Boise, 

ID. (not seen, as cited by Corn and Baker, 2008) 

Wulforst, J., G. Annandale, and A.M.A. Holthuijzen. 2000. C.J. Strike Project FERC 

No. 2055, responses to FERC additional information request no. 13, Terrestrial 

Effects of Load Following. Idaho Power Company, Boise, ID. (not seen, as 

cited by Corn and Baker, 2008)

Wyatt, M. 1985. Trio dedication fire rehab survey, #F274 an F288. Idaho SHPO report 

1989/2939. Bureau of Land Management, Boise District, Boise, ID. (not seen, as 

cited by Corn and Baker, 2008) 

Zoellick, B.W., H.M. Ulmschneider and A.W. Stanley. 2005. Distribution and 

composition of mammalian predators along the Snake River in southwestern 

Idaho. Northwest Science 79(4):265-272. 

Zoellick, B.W., J.M. Ulmschneider, B.S. Cade and A.W. Stanley. 2004. Isolation of 

Snake River islands and mammalian predation of waterfowl nests. J. Wildl. 

Manage. 68(3):650-662. 

Zoellick, B.W. 1999. Stream temperatures and the elevational distribution of redband 

trout in southwestern Idaho. Great Basin Naturalist 59:136–143. 
174 

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175 

7.0 LIST OF PREPARERS 

Federal Energy Regulatory Commission 

James Puglisi— Project Coordinator, Hydrology/Water Quantity, Geology and Soils, 

Developmental Analysis (Civil Engineer; M.S., B.S., Civil Engineering) 

Joseph Adamson—Recreation, Land Use, and Aesthetics (Outdoor Recreation Planner; 

M.A., Science Education; B.S. Forestry and Wildlife) 

Gaylord Hoisington—Geology and Soils (Soil Conservationist; B.S., Recreation) 

Nicholas Jayjack—Water Quality and Fisheries, Threatened and Endangered Species 

(Fisheries Biologist; M.S., Environmental Science in Civil Engineering; B.S. 

Fisheries and Aquatic Sciences) 

Patti Leppert—Recreation and Land Use (Environmental Protection Specialist; M.A. 

Recreation and Parks/Biology; B.S. Recreation and Parks/Biology) 

Dianne Rodman—Terrestrial Resources, Threatened and Endangered Species 

(Ecologist; M.S., Biology) 

Frank Winchell—Cultural Resources (Archaeologist; Ph.D., Archaeology) 

Louis Berger Group 

Ellen Hall—Task Manager, Socioeconomic Resources (Environmental 

Planner/Resource Economist; Ph.D., Resource Economics; M.Ag., Agricultural 

Economics; B.A., History/Economics) 

Kenneth Hodge—Need for Power, Developmental Analysis, Hydrology/Water 

Resources/Geology and Soils (Senior Engineer; B.S., Civil Engineering) 

Coreen Johnson—Editorial Review (Technical Editor; B.A., English/Education) 

Alison Macdougall—Cultural Resources (Senior Environmental Manager; B.A., 

Anthropology) 

Jean Potvin—Recreation, Land Use and Aesthetics (B.S., Recreation and Park 

Management) 

Fred Winchell—Water Resources and Fisheries, Threatened and Endangered Species 

(Fisheries Biologist; M.S., Fisheries Biology) 

Subcontractor Staff 

Meridian Environmental 

Eileen McLanahan—Terrestrial Resources, Threatened and Endangered Species (M.S., 

Biology) 
176 

This page intentionally left blank. 
177 

8.0 LIST OF RECIPIENTS 

Ada County of Board of County 

Commissioners 

650 W Main St 

Boise, ID 83702-5960 

City of Boise 

P.O. Box 500 

Boise, ID 83701-0500 

City f Caldwell 

621 Cleveland Blvd 

Caldwell, ID 83605-4052 

Robert Heinith, Coordinator 

Columbia River Inter-Tribal Fish 

Comm. 

Suite 200 

729 NE Oregon St 

Portland, OR 97232-2174 

Starla K. Roels 

Columbia River Inter-Tribal Fish 

Comm. 

Suite 200 

729 NE Oregon St 

Portland, OR 97232-2174 

Balthasar B. Buhidar 

Division of Environmental Quality 

IDEQ-TFRO 

1363 Fillmore St 

Twin Falls, ID 83301 

Paul Friesema, Professor 

Environmental Policy and Culture 

Program 

304 Scott Hall 

601 University Place 

Evanson, IL 60208 

Environmental Protection Agency 

1435 N Orchard St 

Boise, ID 83706-2239 

Environmental Protection Agency 

Office of Federal Activities 

401 M Street, S.W., Room 537 

Washington, D.C. 20460-0001 

Federal Energy Regulatory Commission 

Portland Regional Office 

805 SW Broadway Fox Tower, Suite 

550 

Portland, OR 97205 

Forest Service 

Regional Hydropower Coordinator 

125 S State St 

Salt Lake City, UT 84138 

Lionel Q. Boyer, Chairman 

Fort Hall Business Council 

P.O. Box 306 

Fort Hall, ID 83203-0306 

Rick Ward, Environmental Staff 

Biologist 

Idaho Department Fish and Game 

3101 S. Powerline Road 

Nampa, ID 83686 

Cynthia Robertson 

Natural Resources Program Coord. 

Idaho Department Fish and Game 

P.O. Box 25 

Boise, ID 83707-0025 

Idaho Department of Environmental 

Quality 

Director 

1410 N. Hilton Street 

Boise, ID 83720-0001 
178 

Douglas Conde, Deputy Attorney 

General 

Idaho Department of Environmental 

Quality 

1410 N Hilton 

Boise, ID 83706-1255 

Craig Shepard 

Idaho Department of Environmental 

Quality 

1410 N. Hilton 

Boise, ID 83706-1255 

Idaho Department of Lands 

State Capitol Building 

1215 West State Street 

Boise, ID 83720-0001 

Steven Schuster 

300 N. Sixth Street, Suite 103 

Boise, ID 83720-0050 

Mary Lucachick, Water Recreation 

Analyst 

Idaho Department of Parks and 

Recreation 

5657 Warm Springs Ave 

Boise, ID 83716 

Phillip J. Rassier, ESQ 

Deputy Attorney General 

Idaho Department of Water Resources 

P.O. Box 83720 

Boise, ID 83720-0098 

State of Idaho 

Office of Attorney General 

700 W. State Street 

P.O. Box 83720 

Boise, ID 83720-0010 

Harriet A. Hensley, Deputy Attorney 

General 

Idaho Office of Attorney General 

700 W. State Street, 2nd Floor 

Boise, ID 83702-0010 

Nathan Gardiner, Attorney 

Idaho Power Company 

1221 W. Idaho Street 

Boise, ID 83702 

Rex Blackburn 

Senior VP & General Counsel 

Idaho Power Company 

P.O. Box 70 

Boise, ID 83702 

Legal Department 

CEO 

Idaho Power Company 

P.O. Box 70 

Boise, ID 83707-0070 

Idaho Public Utilities Commission 

Secretary 

P.O. Box 83720 

Boise, ID 00074 

Sara D Eddie 

Dir. Hydropower & Energy Programs 

Idaho Rivers United 

P.O. Box 1612 

Boise, ID 83701-1612 

Kevin L. Lewis 

Conservation Director 

Idaho Rivers United 

P.O. Box 633 

Boise, ID 83701-0633 

Idaho State Preservation Office 

210 W Main St 

Boise, ID 83702-7264 
179 

City of Kuna 

Kuna City Clerk 

P.O. Box 13 

Kuna, ID 83634-0013 

City of Melba 

Melba City Clerk 

P.O. Box 209 

Melba, ID 83641-0209 

City of Murphy, 

Owyhee County Clerk 

P.O. Box 128 

Murphy, ID 83650-0128 

City of Nampa 

411 3rd St S 

Nampa, ID 83651-3721 

Prescott Brownell, Regional FERC 

Coordinator 

National Marine Fisheries Service 

219 Fort Johnson Road 

Charleston, SC 29412 

Nez Perce Tribal Executive Comm 

P.O .Box 305 

Lapwai, ID 83540-0305 

Nez Perce Water Resource 

Development 

P.O. Box 365 

Lapwai, ID 83540-0365 

County of Owyhee 

Board of County Commissioners 

Murphy, ID 83650 

Shaun Robertson 

Shoshone Bannock Tribe 

P.O. Box 306 

Fort Hall, ID 83203-0306 

William Bacon 

Shoshone-Bannock Tribes 

P.O. Box 306 

Fort Hall, ID 83203-0306 

Alonzo Coby 

Shoshone-Bannock Tribes 

P.O .Box 306 

Fort Hall, ID 83203-0306 

Yvette Tuell 

Fish and Wildlife Department 

Shoshone-Bannock Tribes, 

R 6, Box 863 

Pocatello, ID 83202 

Soil Conservation Commission 

State House 

Boise, ID 83720-0001 

Robert W Stahman, Vice President 

P.O. Box 70 

Boise, ID 83707-0070 

Clive Strong 

Idaho Office of Attorney General 

P.O. Box 83720 

Boise, ID 00074 

Lawerence G Wasden, Superintendant 

U.S. Bureau of Indian Affairs 

1555 Shoshone Cir 

Elko, ID 898015073 

Bob Dach, Hydropower Program 

Manager 

U.S. Bureau of Indian Affairs 

911 NE 11th Avenue 

Portland, OR 97232 

U.S. Bureau of Land Management 

Idaho State Director 

1387 S Vinnell Way 

Boise, ID 83709-1657 
180 

J. William McDonald 

U.S. Bureau of Reclamation 

Pacific Northwest Region 

1150 N Curtis Rd 

Boise, ID 83706-1234 

U.S. Fish and Wildlife Service 

Upper Columbia River Basin Field 

Office 

11103 E Montgomery Dr 

Spokane, WA 99206-4779 

Spokane 

U.S. Fish and Wildlife Service 

Boise Field Office 

1387 S Vinnell Way, Room 368 

Boise, ID 83709-1657 

U.S. Fish and Wildlife Service 

Regional Director 

Attn: FERC Coordinator 

911 NE 11th Ave 

Portland, OR 97232-4169 

Michael D. Crapo, Senator 

United States Senate 

239 Dirksen Senate Building 

Washington, D.C. 20515 

U.S. Army Corps of Engineers 

P.O. Box 2870 

Portland, OR 97208-2870 

U.S. Army Corps of Engineers 

Walla Walla District 

201 N 3rd Ave 

Walla Walla, WA 99362-1876 
Appendix A 

Clean Water Act 

Section 401 Water Quality Certification 
20090817-0003 FERC PDF (Unofficial) 08/13/2009 

02:,'I:,IA L i 

S'OI~ OF lingo 

DEPARTMENT OF 

ENVIRONMENTAL QUALITY 

1410 Nm'~ Hilton - Bo~e, Idakho 83710e ,, (20e) ~ 

May 4, 2009 

,~,-k,.. - ;.' ,~f f'.'7 ~- ,- 

"':..:13 

O.L "IBt~W Ottllr. Oo~m~ 

Terd t.~uem~, ~nldm 

Thomas IL Herlihy 

Executive Director 

Federal Energy Regulatory Commission 

888 First Street, NE 

Washington, DC 20426 

RE: Swan Falls Dam Project - FERC Permit 503 

Dear Mr. Herlihy: 

On June 6, 2008, Idaho Power Company (]PC) requested that DEQ issue a certification, pursuant 

to section 401 of the Clean Water Act, regarding the Company's' application for aNew License 

for the Swan Falls Project that was filed by the Company on June 26, 2008. The original license 

was issued by the Federal Energy Regulatory Commission (FERC) in December 1982. An order 

amending the license was issued in December 1989. This original license was certified by DEQ 

on June 28, 1989. 

Please find enclosed the Idaho DEQ fitud Clean Water Act section 401 Water Quality 

Certification for the Swan Fall Dam Project - FERC Permit 503. 

Questions regt~ding the actions taken in this certification should be directed to Craig Shel~xl , 

Boise Regional Office IDEQ at (208) 373-0557 or crm=.shemerd _(-~dcq,idaho.gov. 

Sincerely, 

Barry N. Burnell 

Water Quality Division Administnator 

BNB:bmm 

Enclosure 

C: Doug Conde - Deputy Attonmy C-¢nend 

Chris Randolph, Idaho Power Company 

Cndg Shcpard - Boise Regional Office 

PrJmto# an Re¢?$1O* Pepor 
~0090817-0003 FERC PDF (Unofficial) 08/13/2009 

Idaho Department of Environmental Quality 

Final §401 Water Quality Certification 

May 4, 2009 

FERC Permit 503, Swan Falls Dam 

Pursuant to the provisions of Section 401(aXl) of the Federal Water Pollution Control 

Act (Clean Water Act), as amended, 33 USC Section 1341 (a)(1), the Idaho Department 

of Environmental Quality (DEQ) has authority to review applications for licens~ 

by the Federal Envrgy Rogulatory Commission (FERC) and issue a water quality 

certification decision. 

On June 6, 2008, Idaho Power Company (IPC) requested that DEQ issue a certification, 

pursuant to section 401 of the Clean Water Act, regarding the Company's' application for 

a New License for the Swan Falls Project that was filed by the Compeny on June 26, 

2008. IPC has no existing measures specific to water quality in the project are~ inits 

license application, IPC proposes two new enhancement measures specific to water 

quality in the project area. These new measures include aqtmfic maclx~hyte (i.e., 

CPOM) mnoval at Swan Falls Dam and water temperature and dissolved oxygen ~DO) 

monitoring in the outflow from the project. 

IPC proposes continued operation of the mmh rake over the turbine intakes to remove 

aquatic macrophytes and debris from the river. This measure would t~'move nutrients and 

oxygen-demanding material from the fiver. Removal of this material would result in 

downstream decreases in floating or submerged matter, excess nutrients, and oxygend~mlwt,'l~rt~ ~At~. 

IPC proposes to monitor temperature mui DO in the outflow l~om Swan Falls Dam. The 

purpose of the monitoring would be to document and report temperature and DO 

conditions at the Swan Falls outflow. An automated system would be installed and 

operated to electronicaUy store measurements every 10 minutes. Temperature end DO 

would be monitored from June 15 through October 15, and the data would be 

summarized for reporting on a montldy basis. The specific location of the system will be 

determined through the development of a water quality monitoring plan required as one 

of the condi~ons oftho IDEQ ~401 certificalion. 

DEQ has considered the application for a license and all other documents filed with 

FERC relating to the application for a license, including specifically the Environmental 

Assessment attached as Exlfibit E to the application. Based upon its review of this 

infoxmation, DEQ certifies that iflPC complies with the terms set forth in the application 

for the license, the terms and conditiom of the li~nse and the terms and conditiom ~ 

Page 1 of 3 
t0090817-0003 FERC PDF (Unofficial) 08/13/2009 

forth in this ~ quality cor~cation, then there is reasonable assuranco the operation of 

tl~ Swan Falls Project will comply witb. the applicable rvquirvmenls of Sections 301, 

302, 303, 306, and 307 oftho Clean Water Act, including the Idaho Water Quality 

Standards (WQS) 0DAPA 58.01.02) and othcz appropriam water quality requirements of 

stare law. 

This certification does not constitute authorization of the permitted activities by any oth~ 

st~e or fed~al agency or private person or entity. This cvrtification does not excus~ the 

permit holder f~om the obligation to obtain any other necessary approvals, authorizations 

or permits. 

M FOLLOWING CONDITIONS ARE ~ARY TO ENSURE 

COMPLIANCE WITH IDAHO WATER QUALITY STANDARDS: 

MONITORING PLAN 

]PC has proposed monitoring tempcxatore and dissolved oxygen at thv Swan Falls 

facility. DEQ agrees that water quality monitoring is nccosmr7. In order to implement 

the ]PC proposed monitoring, and to address DEQ's concerns with water quality in the 

Swan Falls roach oflhv Snake Rivcz, ]PC shall, after issuanco ofaN~v License, develop, 

in consultation with DEQ, a Monitoring Plan that includos tim elemvnts dvsoribed bdow. 

The Monitoring Plan shall be submitted to DEQ for approval within six (6) months after 

isstmnco of a New Liconse. The purpose of the Monitoring Plen is to evaluam data for 

comparison with waist quality stamiards and to help detcnninc the effect, if any, of the 

Swan Falis Project on wamr quality both within the reservoir and downstream Rom th~ 

Swan Falls Projcct. The Monitoring Plan shall include a description of the location and 

method of monitoring tl~ following paramemm, as approlxiate, in the intlow and the 

outflow to tim Swan Falls Proj¢~ discharge flows, dissolved oxy~, to~l dissolved gas 

and wamr mmpvzam~ in the Snaky Rivor. The Monitoring Plan shall inoludc a Quality 

Assurance Control Project Plan (QAPP). The QAPP shall include appropria~ protocols 

for dissolved oxygen, total dissolved gas, wate~ temperature measm'emenm and 

continuous flow monitoring. Upon approval, the Monitoring Plml, including the QAPP, 

shall be implememed in accordan~ with DEQ's approval. 

DATA REVIEW DECISION MAKING 

1. IPC shall submit annual reports to DBQ that snnmafiz8 the results of its water 

quality moni~ring as set out in the approved Monitoring Plan. 

2. DEQ intenda to ~-,vicw th~ annual data and report of findin~ in cool~ua~on and 

consultation with the Idaho Deparlment ofFish and Game 0DF(3). Afl~ such 

coord/mfion and consultation, DEQ shall proceed as follows: 

a. ARer five (5) years, ]PC may reqtmst the termination of some or al| of the 

monitoring descn2~ed in tho approved Monitoring Plan that is in addition 

to tl~ monitoring proposed by IPC in its licenso application. Within sixty 

(60) days of tim request, DEQ shall notify ]PC of its d~sion regarding 

whether termination of thv monitoring is appropriate. 

Page 2 of 3 
~0090817-0003 FERC PDF (Unofficial) 08/13/2009 

b. If after review of an annual report, DEQ determines the data shows that 

the operation of the Swan Falls Project causes or conm~outes to a violation 

of Water Quality Standards, Idaho Power Company will be req~red to 

develop a contingency plan, within six (6) months of DEQ's determination 

that addresses IPC% contribution to the violation. 

OTHER PROVISIONS 

IDEQ resezves the right to amend this certification as authorized under applicable law if 

it discovers new infomutfion not reasonably ascertainable regarding Project impacts that 

have a significant adverse effect on water quality which is not addressed in this 401 

certification. 

The final Section 401 Water Quality Certification may be appealed by submitting a 

petition to i~ a contested case, pursuant to Idaho Code § 39-107(5), and the Rules of 

Administrative Procedure Before the Board of En "vn-onmental Quality, IDAPA 58.01.23, 

within thirty-five (35) days of the date of the final certification. 

Page 3 of 3