Walla Walla District

Final Dredged Material Management Plan and

Environmental Impact Statement (DMMP/EIS)

McNary Reservoir and Lower Snake River Reservoirs

Lead Agency:

U.S. Army Corps of Engineers

Walla Walla District

210 North 3rd Avenue

Walla Walla, WA 99362-1876

Cooperating Agency:

U.S. Environmental Protection Agency

Region 10

1200 Sixth Avenue

Seattle, WA 98101

For further information contact:

Jack Sands, Project Manager

U.S. Army Corps of Engineers

Walla Walla District

201 North 3rd Avenue

Walla Walla, WA 99362-1876

(509) 527-7287

Record of Decision:

At least 30 days after publishing the Notice of Availability of the Final

DMMP/EIS in the Federal Register, the Corps will prepare a Record of

Decision documenting the action resulting from this process.

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Abstract:

This Final DMMP/EIS presents the Corps of Engineers' programmatic plan for maintenance of the authorized navigation channel in

the lower Snake River reservoirs between Lewiston, Idaho, and the Columbia River, and McNary reservoir on the Columbia River for

20 years; for management of dredged material from these reservoirs; and for maintenance of flow conveyance capacity at the most

upstream extent of the Lower Granite reservoir for the remaining economic life of the dam and reservoir project (to year 2074). The

Corps, along with the U.S. Environmental Protection Agency, analyzed four alternatives for this Final DMMP/EIS: Alternative 1 - No

Action (No Change) - Maintenance Dredging With In-Water Disposal, Alternative 2 - Maintenance Dredging With In-Water Disposal

to Create Fish Habitat and a 3-Foot [0.9-meter (m)] Levee Raise, Alternative 3 - Maintenance Dredging With Upland Disposal and a

3-Foot (0.9-m) Levee Raise, and Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m)

Levee Raise (Recommended Plan/Preferred Alternative).

Table of Contents

Executive Summary

Introduction

Authority

Purpose and Need

Local Sediment Management Group

Alternatives

Environmental Effects of Alternatives

Recommended Plan/Preferred Alternative

Section 1 - Introduction

1.1 Study Authority

1.2 Purpose and Need

1.3 Description of the Study Area

1.4 Existing Federal Project Authority

1.5 History and Background

1.6 Related Action Programs

1.7 Economic Justification

1.7.1 Navigation

1.7.2 Conveyance Capacity

1.8 Local Sediment Management Group

1.9 Local Sponsors

Section 2 - Alternatives

2.1 Initial Options

2.2 Measures Considered

2.2.1 Change Upstream Land Uses and Land Management Practices to Control Sediment

2.2.2 Reservoir Drawdown

2.2.3 In-Water Sedimentation Control

2.2.4 Dredging and Disposal of the Dredged Material

2.2.5 Construct Upstream Sediment Traps

2.2.6 Levee Modification

2.3 Formulation of Alternatives to be Considered In Detail

2.3.1 Screening Process

2.3.2 Methodology and Evaluation Criteria

2.4 Measures Removed From Further Consideration

2.5 Alternatives Selected for Further Consideration

2.5.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

2.5.2 Alternative 2 - Maintenance Dredging With In-Water Disposal To Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

2.5.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

2.5.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

2.6 Mitigation

2.7 Evaluation/Selection of Plan

2.8 Recommended Plan/Preferred Alternative

2.8.1 Dredging Activity

2.8.2 Dredging Template Design

2.8.3 Dredging Quantities

2.8.4 Material Types

2.8.5 Dredged Material Management Process

2.8.6 Levee Raise

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2.8.7 The 2002-2003 Dredging

2.8.8 Monitoring

2.8.9 ESA Consultation Provisions

2.8.10 Regional Acceptability and Public Comments

2.8.11 Other Considerations

Section 3 - Affected Environment

3.1 Aquatic Resources

3.1.1 Fish

3.1.2 Plankton and Benthic Organisms

3.1.3 Aquatic and Terrestrial Plants

3.1.4 Fish Predation

3.2 Terrestrial Resources

3.2.1 Vegetation

3.2.2 Wildlife

3.3 Endangered Species Act

3.3.1 Fish

3.3.2 Wildlife

3.3.3 Plants

3.3.4 Species of Concern

3.4 Recreation

3.4.1 Recreation Facilities and Activities

3.4.2 Facility Use/Visitation Patterns

3.5 Cultural Resources

3.5.1 Cultural Resources Definition

3.5.2 Cultural Reources Significance

3.5.3 Culture History

3.5.4 Existing Cultural Resources Environment

3.6 Socioeconomics

3.6.1 Population

3.6.2 Employment and Income

3.6.3 Environmental Justice Communities

3.7 Transportation

3.7.1 River Navigation

3.7.2 Railroads

3.7.3 Highway/Roadway

3.8 Geology and Soils

3.9 Water Quality/Water Resources

3.9.1 Water Quality Criteria and Standards

3.9.2 Sediment Quality

3.9.3 Wetlands

3.9.4 Floodplain Areas

3.10 Hazardous, Toxic, and Radioactive Waste (HTRW)

3.10.1 Dredged Material

3.10.2 Upland Disposal Sites

3.11 Air Quality

3.11.1 Meteorology

3.11.2 Fugitive Dust Emissions

3.11.3 Equipment Exhaust Emissions

3.11.4 National Ambient Air Quality Standards (NAAQS)

3.11.5 Washington Air Quality Standards

3.11.6 Idaho Air Quality Standards

3.11.7 Oregon Air Quality Standards

3.12 Noise

3.12.1 Background Information on Noise

3.12.2 Existing Noise Levels

3.12.3 Washington Noise Control Standards

3.12.4 Idaho Noise Control Standards

3.12.5 Oregon Noise Control Standards

3.13 Aesthetics

3.13.1 Visual Resources

3.13.2 Viewers and Viewing Patterns

3.14 Native American Tribes and Communities

3.14.1 Summary

3.14.2 Introduction

3.14.3 Issues and Concerns

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3.14.4 Government-to-Government Relations

Section 4 - Environmental Effects of Alternatives

4.1 Aquatic Resources

4.1.1 Dredged Material Removal

4.1.2 Dredged Material Disposal

4.1.3 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

4.1.4 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

4.1.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

4.1.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

4.1.5 Critical Habitat Considerations

4.1.6 Mitigation

4.2 Terrestrial Resources

4.2.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

4.2.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

4.2.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

4.2.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

4.2.5 Mitigation

4.3 Endangered Species

4.3.1 Fish

4.3.2 Terrestrial Wildlife

4.3.3 Plants

4.4 Recreation

4.4.1 Recreation Facilities, Activies, and Use Patterns

4.4.2 Mitigation

4.5 Cultural Resources

4.5.1 Cultural Resources Effects

4.5.2 Mitigation

4.6 Socio-Economics

4.6.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

4.6.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

4.6.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

4.6.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

4.6.5 Low-Income or Minority Populations

4.6.6 Mitigation

4.7 Transportation

4.7.1 River Navigation

4.7.2 Railroads

4.7.3 Highways/Roadways

4.7.4 Mitigation

4.8 Geology and Soils

4.8.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

4.8.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

4.8.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

4.8.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

4.8.5 Mitigation

4.9 Water Quality/Water Resources

4.9.1 Water Quality

4.9.2 Wetlands

4.9.3 Floodplains

4.10 Hazardous, Toxic, and Radioactive Waste

4.10.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

4.10.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

4.10.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

4.10.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

4.10.5 Mitigation

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4.11 Air Quality

4.11.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

4.11.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

4.11.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

4.11.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

4.11.5 Mitigation

4.12 Noise

4.12.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

4.12.2 Alternative 2 - Maintenance Dredging With In-Water Disposal

and a 3-Foot (0.9-m) Levee Raise

4.12.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

4.12.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

4.12.5 Mitigation

4.13 Aesthetics

4.13.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

4.13.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

4.13.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

4.13.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

4.13.5 Mitigation

4.14 Native American Tribes and Communities

4.14.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

4.14.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

4.14.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

4.14.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

4.14.5 Mitigation

4.15 Cumulative Effects

4.15.1 The DMMP/EIS Cumulative Effects

4.15.2 Cumulative Effects Findings

4.15.3 Mitigation

Section 5 - Compliance With Applicable Environmental Laws and Regulations

5.1 National Environmental Policy Act (NEPA)

5.1.1 American Indian Religious Freedom Act (AIRFA)

5.1.2 Archaeological Resources Protection Act

5.1.3 Clean Air Act

5.1.4 Coastal Zone Management Act

5.1.5 Endangered Species Act (ESA)

5.1.6 Farmland Protection Policy Act

5.1.7 Federal Water Pollution Control Act (Clean Water Act)

5.1.8 Federal Water Project Recreation Act

5.1.9 Fish and Wildlife Coordination Act

5.1.10 Fishery Conservation and Management Act of 1976

5.1.11 Land and Water Conservation Fund Act

5.1.12 Migratory Bird Conservation Act

5.1.13 National Environmental Policy Act (NEPA)

5.1.14 Native American Grave Protection and Repatriation Act (NAGPRA)

5.1.15 National Historic Preservation Act (NHPA)

5.1.16 Pacific Northwest Electric Power Planning and Conservation Act

(Northwest Power Act)

5.1.17 Pollution Control at Federal Facilities

5.1.18 River and Harbor Act of 1899

5.1.19 Wild and Scenic River Act

5.1.20 Wilderness Act

5.2 Executive Orders

5.2.1 Executive Order 11593, Protection and Enhancement

of the Cultural Environment, May 13, 1971

5.2.2 Executive Order 11988, Floodplain Management Guidelines, May 24, 1977

5.2.3 Executive Order 11990, Protection of Wetlands

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5.2.4 Executive Order 12898 - Federal Actions to Address Environmental Justice in Minority Populations

and Low-Income Populations, February 11, 1994

5.2.5 Executive Order 13007, Native American Sacred Sites, May 24, 1996

5.3 Executive Memoranda

5.3.1 Council on Environmental Quality Memorandum August 11, 1990, Analysis of Impacts

on Prime or Unique Agricultural Lands In Implementing NEPA

5.4 State Statutes

Section 6 - Coordination, Consultation, and Public Involvement

6.1 Scoping

6.2 Meetings With Resource Agencies

6.3 Endangered Species Act Consultation

6.4 Tribal Consultation

6.4.1 Laws and Statutes Relating to Tribal Interests

6.4.2 U.S. Army Corps of Engineers Policy Guidance and American Indian Tribes

6.4.3 Government-to-Government Consultation Status

6.5 Public Review

Section 7 - List of Preparers

Section 8 - Distribution List

Section 9 - Glossary and Acronyms

9.1 Glossary

9.2 Acronyms

Section 10 - References

List of Figures

Figure ES-1 DMMP/EIS Plan Formulation Process

Figure ES-2 Cross Section of the Phased Development Disposal Technique for Creating Shallow Water

Habitat

Figure ES-3 Shallow Water Sediment Placement Technique Using a Bottom Dump Barge

Figure ES-4 Disposal Site Selection Decision Tree

Figure 2-1 DMMP/EIS Plan Formulation Process

Figure 2-2 Schematic Comparison of Navigation Channel Maintenance Dredging and Flow Conveyance

Dredging

Figure 2-3 Shallow Water Disposal - Bottom Dump Process

Figure 2-4 Shallow Water Disposal - Drag Beam Contouring Process

Figure 2-5 Joso Dredged Material Disposal Site

Figure 2-6 Lower Granite Reservoir - In-Water Disposal Areas

Figure 2-7 Disposal Site Selection Decision Tree

Figure 2-8 Cross Section of the Phased Development Disposal Technical for Creating Shallow Water

Habitat

Figure 3-1 Typical Anadromous Salmonid Migration Windows

Figure 3-2 Project Area 1990 Census Tract Data: Percent Inhabitants Living in Poverty

Figure 3-3 Project Area 2000 Census Tract Data: Percent Minority Inhabitants

Figure 3-4 Aesthetics of the Study Area

List of Plates

Plate 1 Study Area

Plate 2 McNary Dam and Reservoir: RM 289 - 298

Plate 3 McNary Reservoir: RM 299 - 310

Plate 4 McNary Reservoir: RM 310 - 321

Plate 5 McNary Reservoir: RM 322 - 329

Plate 6 McNary Reservoir: RM 330 - 341

Plate 7 McNary Reservoir: RM 342 - 352

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Plate 8 Ice Harbor Dam and Reservoir: RM 9 - 22

Plate 9 Ice Harbor Reservoir: RM 21 - 35

Plate 10 Lower Monumental Dam and Reservoir: RM 34 - 49

Plate 11 Lower Monumental Reservoir: RM 48 - 61

Plate 12 Little Goose Dam and Reservoir: RM 60 - 74

Plate 13 Little Goose Reservoir: RM 73 - 87

Plate 14 Little Goose Reservoir: RM 84 - 99

Plate 15 Lower Granite Dam and Reservoir: RM 99 - 116

Plate 16 Lower Granite Reservoir: RM 114 - 128

Plate 17 Lower Granite Reservoir: RM 127 - 147

Plate 18 3-Foot Levee Raise

List of Tables

Table ES-1 Comparison of Alternatives

Table ES-2 Environmental Effects Summary Matrix

Table 1-1 History of Dredging in Lower Snake River and McNary Reservoirs

Table 1-2 Comparison of Alternatives

Table 2-1 Measures Addressing Program Purposes

Table 2-2 Cost Sharing of Beneficial Use of Dredged Material

Table 2-3 Evaluation Criteria

Table 2-4 Average Annual Costs

Table 2-5 Measures Removed From Further Consideration in This DMMP/EIS

Table 2-6 Comparison of Alternatives

Table 2-7 Dredging Options by Area

Table 2-8 Environmental Effects Summary Matrix

Table 2-9 Final Alternative Evaluation Matrix

Table 2-10 Estimated Dredging Cycles and Dredged Material Volumes Per Cycle

Table 3-1 Recreation Facilities in the Lower Snake River and McNary Reservoirs

Table 3-2 Recreation Facility Visitation Lower Snake River Reservoirs, FY 95 - FY 97

Table 3-3 Study Area Population by County

Table 3-4 Study Area 1997 Employment by County

Table 3-5 Study Area Income by County

Table 3-6 Percent Poverty of Project Area Census Tracts 1990

Table 3-7 Percent Minorities in Project Area Census Tracts 2000

Table 3-8 Inventory of Commercial Facilities on the Columbia and Snake River Reservoirs Above McNary

Table 3-9 Projected Commodity Growth for Shipments Above McNary (1,000 Tons)

Table 3-10 Key Highways and Roadways

Table 3-11 Water Quality Standards in Oregon, Idaho, and Washington

Table 3-12 Test Description and Method

Table 3-13 Lower Granite Tailrace Temperature Data for Water Year 2000

Table 3-14 Ice Harbor Tailrace Temperature Data for Water Year 2000

Table 3-15 Snake River at Anatone, Temperature Data for Water Year 2000

Table 3-16 McNary Tailrace Temperature Data for Water Year 2000

Table 3-17 Clearwater River at Spalding, Temperature Data for Water Year 2000

Table 3-18 Percent of Sample by Grain Size (ASTM Standard Sieve)

Table 3-19 Elutriate Results With Background Values

Table 3-20 National Ambient Air Quality Standards

Table 3-21 Weighted Sound Levels and Human Response

Table 4-1 Environmental Effects Summary Matrix

Table 4-2 Quantification of Three Water Depth Habitats in Lower Granite Reservoir, Snake River (SR)

and Clearwater River (CF) During the Early- to Mid-1980s

Table 7-1 List of Preparers - U.S. Army Corps of Engineers, Walla Walla District

Table 7-2 List of Preparers - Consultant Team

Appendices

Appendix A - Hydrologic Analysis

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Appendix B - Cost Estimates

Appendix C - Economic Analysis

Appendix D - Upland Disposal Conceptual Design

Appendix E - Levee Modification/Extension Analysis

Appendix F - Endangered Species Act Consultation for Anadromous Fish Species

Appendix G - Endangered Species Act Consultation for Non-Anadromous Fish and Terrestrial Species

Appendix H - Water and Sediment Quality

Appendix I - Section 404(b)(1) Evaluation

Appendix J - Dredged Material Evaluation Framework

Appendix K - Aquatic Resources

Appendix L - Cultural Resources (Deleted - Detailed Cultural Resources Information is Presented in this Final DMMP/EIS)

Appendix M - Monitoring Plan

Appendix N - Dredging Proposed for Winter 2002-2003

Appendix O - Response to Comments on the Draft DMMP/EIS

EXECUTIVE SUMMARY

INTRODUCTION

The U.S. Army Corps of Engineers' Walla Walla District (Corps) is responsible for maintenance of the portion of the Columbia-Snake

River inland navigation waterway that includes the Ice Harbor, Lower Monumental, Little Goose, and Lower Granite reservoirs on the

Snake River, and McNary reservoir on the Columbia River. The Corps maintains a 14-foot- [4.3-meter (m)-] deep and 250-foot-

(76.2-m) wide navigation channel through these reservoirs, which have historically required some level of dredging. These reservoirs

are part of an inland navigation system that provides slackwater navigation from the mouth of the Columbia River near Astoria,

Oregon, to port facilities on the Snake and Clearwater Rivers in Lewiston, Idaho, and Clarkston, Washington.

The Corps, in cooperation with the U.S. Environmental Protection Agency (EPA), is developing a long-range plan for the

maintenance of the navigation channel from Lower Granite through McNary reservoirs (see plate 1). The Corps has completed a

Draft Dredged Material Management Plan and Environmental Impact Statement (DMMP/EIS) for McNary reservoir and the lower

Snake River reservoirs. The DMMP/EIS evaluates the likely environmental effects of the plan alternatives on a long-term,

programmatic basis. Public comments on the plan and EIS will be considered by the Corps prior to the selection and

implementation of a final plan. In addition, as specific proposals to implement the plan are developed and evaluated by the Corps

over the 20-year term of the DMMP, the Corps will solicit public comments on these specific proposals. This Executive Summary

presents the key components of the Corps’ programmatic plan for:

Maintenance of the authorized navigation channel in the lower Snake River reservoirs between Lewiston, Idaho, and Columbia

River in the McNary reservoir for 20 years after the Record of Decision (ROD) is signed.

Maintenance of limited public facilities within the reservoirs, such as recreational boat basins and irrigation intakes for the

wildlife habitat management units (HMUs).

Management of dredged material from these reservoirs.

Maintenance of flow conveyance capacity at the most upstream extent of the Lower Granite reservoir for the remaining

economic life of the project (to year 2074).

Plates 2 through 17 provide further information on area features and likely dredging and disposal areas. Based on current

information, the plates depict the sites most likely to be dredged. Not every location shown will be dredged and not every location to

be dredged is necessarily shown on the plates. The size and shape of the areas are approximate and will be further defined when

the need to dredge is identified. This Executive Summary presents a description of the DMMP planning process, including: the

purpose and need; the plan alternatives; the anticipated environmental effects of the plan alternatives; and the Corps’ preferred

alternative.

AUTHORITY

The portion of the Columbia-Snake Rivers navigation system addressed in the DMMP was authorized by Section 2 of the River and

Harbor Act of 1945 (Public Law 79-14, 79th Congress, 1st Session) and approved March 2, 1945, in accordance with House

Document 704, 75th Congress, 3rd Session. The projects include:

McNary Lock and Dam (McNary) - Lake Wallula, Columbia and Snake Rivers, Oregon and Washington

Ice Harbor Lock and Dam (Ice Harbor) - Lake Sacajawea, Snake River, Washington

Lower Monumental Lock and Dam (Lower Monumental) - Lake Herbert G. West, Snake River, Washington

Little Goose Lock and Dam (Little Goose) - Lake Bryan, Snake River, Washington

Lower Granite Lock and Dam (Lower Granite) - Lower Granite Lake, Snake River, Washington and Idaho

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Each of these projects is authorized to provide slackwater navigation, including locks and a 14-foot- (4.3- m-) deep channel.

Additionally, although not part of the DMMP/EIS, each project is authorized to provide hydroelectric power generation, irrigation,

recreation, and wildlife habitat.

The Corps study was initiated under guidance provided in Engineer Circular (EC) 1165-2-200, Policy - Dredged Material

Management Plans, which directed the development of DMMP's for Federal navigation projects. It is the Corps’ policy to manage

dredged material associated with the construction or maintenance dredging of navigation projects in a manner that is the least

costly, is consistent with sound engineering practice, and meets Federal environmental standards. Guidance for developing

DMMP's has now been incorporated into the current revision of Engineer Regulation (ER) 1105-2-100, Planning Guidance Notebook.

The ER 1105-2-100 also provides the requirements, as well as principles and guidelines, for conducting planning studies within the

Corps’ Civil Works program and ensuring environmental compliance through the planning process. Section 3-2 of ER 1105-2-100

provides specific guidance on the maintenance of navigation projects and the preparation of DMMP's. A least-cost alternative that is

compliant with environmental laws forms the "base plan," against which other plan alternatives can be compared. Through the

DMMP planning process, the Corps has considered a range of management strategies (including approaches to reduce the need

for dredging and to beneficially use dredged materials) and has incorporated these strategies into its alternatives development and

evaluation process.

In addition, on May 4, 1995, the Corps Director of Civil Works provided guidance to the Commander, North Pacific Division, by

memorandum entitled "Lower Granite Lock and Dam, Washington, Sedimentation Studies Related to the Level of Protection

Provided to the City of Lewiston, Idaho." This memorandum discussed a study to evaluate restoring the performance of project

levees constructed to protect Lewiston, Idaho, from inundation caused by the Lower Granite project. It states, "The study should

evaluate a range of alternative risk management plans, including modifications in the operation of the project and increased

dredging." In compliance with this memorandum, consideration of reestablishing the flow conveyance capacity at Lewiston, Idaho is

included in the DMMP.

PURPOSE AND NEED

The purpose of the DMMP is threefold:

To develop and evaluate alternative programs to maintain the authorized navigation channel and certain publicly owned

facilities in the lower Snake River and McNary reservoirs for the next 20 years;

1.

To develop and evaluate alternative measures to maintain the flow conveyance of the Lower Granite reservoir for the remaining

economic life of the project (through 2074);

2.

To develop and evaluate alternative programs of managing dredged material in a cost-effective, environmentally acceptable,

and, wherever possible, beneficial manner.

3.

The Corps is authorized to maintain a navigation system on the lower Snake and Columbia Rivers and to manage the lock and

dam/navigation projects (generally referred to as "projects" or "reservoirs" in this document) on the lower Snake River from Lewiston,

Idaho, to the McNary Lock and Dam project at Umatilla, Oregon, on the Columbia River (which includes the confluence of the

Columbia and Snake Rivers). The Corps also maintains publicly owned recreational areas (such as marinas and swimming

beaches), irrigation intake facilities for wildlife HMUs and recreation areas, and port access channels within the lower Snake River

and McNary reservoirs. Historically, the Corps has dredged accumulated sediments from the navigation channel and the other

facilities noted above on these reservoirs in order to maintain their operational capacities. Maintenance dredging actions are in

response to a variety of conditions including, but not limited to: emergency situations which would result in an unacceptable hazard

to navigation; program periodic dredge maintenance of known persistent shoal areas which impede navigation; and removal of

sediment that presents a hydraulic flow impediment.

In addition, sediment accumulation in the upstream reach of Lower Granite reservoir at the confluence of the Clearwater and Snake

Rivers has reduced the flow conveyance capacity of the river channel. If allowed to continue, this sedimentation would reduce the

flow capacity to a point that the Standard Project Flood [(SPF) an estimated or hypothetical flood that might be expected from the

most severe combination of weather and flow conditions that are considered reasonably characteristic of the geographical area]

could potentially overtop the levees in Lewiston, Idaho, before the end of the economic life of the project is reached in 2074. To

date, dredging has been the method of choice for the removal of this sediment and restoration of the flow capacity.

LOCAL SEDIMENT MANAGEMENT GROUP

A Local Sediment Management Group (LSMG) has been formed, and has met on three occasions (July 2000, February 2001, and

December 2001) to provide input and discussion in the development of the DMMP, as well as during the plan’s implementation (i.e.,

the dredging and dredged material management activities). This group has been formed consistent with the inter-agency National

Dredging Team’s guidance. Roles within the LSMG will continue to develop in accordance with policies and procedures currently

evolving for the Regional Dredging Team (RDT), as referred in the April 26, 2002 policy letter jointly signed by Brigadier General

David A. Fastabend (Corps of Engineers Northwest Division Commander) and L. John Iani (EPA Region 10 Administrator).

The LSMG would assist in the development and adoption of appropriate method(s) for management of dredging and use and/or

disposal of dredged material from Federal navigation and maintenance projects and dredging activities regulated under Section 404

of the Clean Water Act. In the formulation of these management policies, the LSMG would be asked to consider key environmental

laws and regulations involved in this process; consider the responsibilities of other Federal, state, and local resource agencies; and

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help develop a coordination process for dredging and beneficial use of dredged material. In addition, the LSMG would assist the

Corps in evaluating dredging and dredged material management activities and options consistent with an adaptive management

approach.

The general objectives of the LSMG are to:

Provide an interagency approach to dredged material management.

Promote consistency in dredging and sediment management activities.

Assist in development of monitoring plans and a sediment sampling and testing framework.

Facilitate adaptive management and beneficial use of dredged materials.

Promote consideration of all environmental laws and regulations.

Consider necessary cultural resource protection.

Discuss and evaluate possible strategies to reduce sediments entering the lower Snake River system.

Involve other stakeholder groups and pursue consistency with their plans.

The Corps anticipates that the LSMG will convene regularly, either annually or semi-annually, depending on dredged material

management activities. It is envisioned that the LSMG will consider proposed dredging within a given timeframe, suggest strategies

to reduce dredging requirements, provide suggestions for promising beneficial uses of dredged materials, and comment on

proposals for in-water habitat creation using dredged materials. The LSMG would also serve as a forum for providing suggestions to

the Corps on improving the implementation of the DMMP.

As situations develop which call for maintenance dredging, the LSMG would be informed. The situations expected to cause

maintenance dredging could include, but would not be limited to:

Emergencies involving shoaled areas that pose a serious risk to navigation of commercial vessels as indicated by records of

groundings, complaints by shippers, and/or condition surveys of the navigation channel.

Programmed/periodic dredge maintenance activities based on well-established historical records of persistent shoaling in a

navigation channel that could pose a serious risk to navigation of commercial vessels.

Shoaled areas that pose a serious risk to navigation and moorage of recreational craft as indicated by comments of operators

of recreational boat facilities and/or condition surveys.

Sedimentation to irrigation intakes associated with Lower Snake River Habitat Management Units (HMU) which restricts the

ability to deliver irrigation water to the HMU.

Advanced maintenance, of a commercial navigation channel or berth which historically requires dredging to remove shoals

that pose a serious risk to navigation, when an opportunity to meet a specific environmental restoration need for beach

nourishment exists and/or when the dredging can be combined with other maintenance dredging to lower the cost and

minimize the dredge related disturbance to transportation and local business activities.

Federal and state agencies with resource management and regulatory responsibilities applicable to the development and

implementation of the DMMP, and affected Native American Tribes, have been asked to participate in the LSMG. Additionally, public

ports within the study area have been invited to participate in the LSMG. Other local entities (e.g., counties, municipalities,

environmental groups, and transportation and industrial interests) with an interest in management of the resources involved in

dredging and disposal activities have been invited to participate.

The LSMG has been identified as a forum for discussion of possible measures to reduce sedimentation in the lower Snake River

system and, as such, land management and conservation agencies like the U.S. Forest Service, the Natural Resources

Conservation Service, and others that may have a role in sediment reduction strategies, will be asked to participated in the LSMG.

ALTERNATIVES

The Corps of Engineers’ planning guidelines and the National Environmental Policy Act require the consideration and analysis of a

broad range of alternatives in the development of the DMMP/EIS. A summary of the process the Corps employed to develop and

evaluate plan alternatives is illustrated in figure ES-1.

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Figure ES-1. DMMP/EIS Plan Formulation Process

Plan Measures Development and Evaluation

Initially, a broad range of measures that either partially or completely fulfilled the purpose and need were considered in the

development of plan alternatives. These measures included:

Sediment deposition reduction.

Dredging.

Management of dredged materials.

Raising levees in the Lewiston, Idaho, area.

In accordance with the requirements of the NEPA, a broad range of alternatives that could potentially meet the stated purpose and

need was developed. The Corps conducted public scoping meetings, consulted with state and Federal environmental and resource

agencies, and conducted technical studies to develop a range of conceptual alternatives that addressed the plan’s purpose and

need. Multiple scenarios which included sediment deposition reduction, dredging, dredged material management, and/or levee

raises were considered in the development of plan measures. A range of alternative strategies within each of the plan measures was

developed and evaluated.

Sediment deposition reduction strategies that were considered included: changes in upstream land uses to control sediments

entering the system; pool draw-down; in-water sedimentation controls that would prevent sediments from being deposited within the

navigation channel, including Bendway weirs and "bubble curtains" around the navigation channel; and construction of upstream

sediment traps.

Dredging scenarios included maintenance dredging only on an as-needed basis, dredging 300,000 cubic yards (cy) [229 366.5

cubic meters (m3)] per year, dredging 1,000,000 cy (764 555 m3) per year, and dredging 2,000,000 cy (1 529 110 m3) per year. The

three scenarios that included dredging beyond navigation maintenance requirements were intended to provide flow conveyance

capacity in Lower Granite reservoir.

Similarly, several levee raise alternatives in the Lewiston, Idaho, area were considered. These included: 3-foot, 4-foot, 8-foot, and

12- foot (0.9-m, 1.2- m, 2.4- m, and 3.7- m) levee raise options.

Finally, a range of dredged material management options were developed and evaluated. These options included upland disposal

of dredged material, in-water disposal of dredged material, and beneficial uses of dredged material. Several in-water disposal

options were considered, such as beneficially using dredged sand and gravel to create shallow-water fish habitat.

The Corps may need to perform dredging on an emergency basis. Potential situations that could require emergency dredging

include high flows depositing sediment that block the navigation channel or rock could be swept into the navigation lock approach

posing an unacceptable navigation hazard. For an emergency dredging situation, the Corps would perform environmental

coordination on an expedited basis as much as possible before initiating the emergency dredging.

An iterative screening process was developed that consisted of formulating alternatives from the most viable program measures

above, evaluating each alternative and selecting alternatives for further detailed consideration. Preliminary evaluation criteria were

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then developed to determine the alternatives that were feasible, reasonable, and should be considered in detail. These criteria

considered whether:

The alternatives were cost-effective, while either providing environmental benefits or causing the least environmental damage.

The alternatives provided a way to regain and/or maintain channel capacity to provide an acceptable level of flow conveyance

capacity resulting in flood protection (based on the results of a risk-based analysis) in the Lewiston-Clarkston area.

The alternatives have acceptable impacts on other project uses (such as shippers and recreational users).

Based on these preliminary screening criteria, measures that were incorporated into plan alternatives included combinations of

dredging and levee raises, with consideration of upland disposal/beneficial use and in- water disposal/beneficial use of dredged

materials.

A set of more detailed screening criteria were then developed to evaluate the relative impacts, costs, and/or benefits of a set of

dredging and levee alternative combinations. Application of these criteria facilitated the identification of alternatives that were

considered feasible, reasonable, and would be evaluated in detail. The identified alternatives are summarized in table ES-1 and

presented in detail below:

Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Alternative 1 represents the continuation of historic maintenance of the authorized navigation channel in the study area. As such,

this alternative includes those activities (specifically, mechanical dredging and in-water disposal) that have been performed in the

recent past to maintain the authorized depths in the navigation channels of the lower Snake River and McNary reservoirs. The areas

covered include Lake Wallula behind McNary Lock and Dam on the Columbia River and the reservoirs behind Ice Harbor, Lower

Monumental, Little Goose, and Lower Granite on the lower Snake River (see plates 2 through 17). This navigation project provides

for a 14- foot by 250- foot (4.3-m by 76.2- m) channel within each reservoir with at least a 15-foot (4.6-m) depth over the sills at each

of the locks. This alternative would provide the authorized navigation clearance and provide some flow conveyance capacity in

Lower Granite reservoir, based on maintenance dredging. Maintenance dredging would be done on an as-needed basis (possibly

as often as every 2 to 3 years) and would generate up to 340,000 cy (259 948.7 m3) per dredging activity. Additionally, dredging

could only occur during an in-water work "window" approved by the National Marine Fisheries Service (NMFS). This window

represents the time of year when dredging and disposal activities would have minimal effects on salmonid species. The current

in-water work window is December 15 through March 1 for the lower Snake River reservoirs and December 1 to March 31 for the

Columbia River. The Corps also periodically conducts maintenance dredging around public recreation areas (such as swimming

beaches and boat basins) and irrigation intakes for wildlife HMU's managed by the Corps (see plates 2 through 17).

Disposal of dredged materials under alternative 1 would be consistent with disposal methods utilized during recent dredging cycles:

dredged materials would be loaded onto bottom-dump barges and transported to the disposal site. Dredged materials would be

sampled for particle size and sediment quality prior to dredging. Historic testing for sediment quality has indicated that dredged

sediments are suitable for in-water disposal. As such, fine- grained materials (i.e., silts) would be disposed in deep-water areas and

sand, gravel, and cobbles would be used to create shallow-water fish habitat within the study area reservoirs (using techniques

similar to those in alternative 2, described below).

Table ES-1

Comparison of Alternatives1

Alternative Dredged Material Disposal Levee Modification

Relocation/

Acquisition Requirements

1 - No Action (No

Change)--Maintenance

Dredging With In-Water

Disposal

In-Water; silt in deep water;

sand, gravel, and cobbles to

create shallow-water fish

habitat.

None None

2 - Maintenance Dredging With

Beneficial In-Water Disposal

and a 3-Foot (0.9-m) Levee

Raise

Create shallow-water fishery

habitat. Material unsuitable for

in-water disposal to Joso

upland site.

Raise levees up to 3 feet (0.9

m) to maintain flow conveyance

capacity

Raising of two roadways

3 - Maintenance Dredging With

Upland Disposal and a 3-Foot

(0.9-m) Levee Raise

Upland at Joso site in Lower

Monumental reservoir

Raise levees up to 3 feet (0.9

m) to maintain flow conveyance

capacity

Raising of two roadways

4 - Maintenance Dredging With

Beneficial Use of Dredged

Material and a 3-Foot (0.9-m)

Levee Raise

Beneficial use, either upland or

in water.

Material unsuitable for in-water

disposal to Joso upland site.

Raise levees up to 3 feet (0.9

m) to maintain flow conveyance

capacity

Raising of two roadways

Note:

1Includes maintenance of the authorized navigation channels of the lower Snake River reservoirs and McNary reservoir; maintenance dredging of access channels to port and moorages on an as-needed basis, public

recreation areas (swimming beaches and boat basins), irrigation intakes for wildlife HMUs managed by the Corps; and flow conveyance capacity of the Lower Granite reservoir.

Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat and a 3-Foot (0.9-m) Levee Raise

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This alternative considers the same dredging activities with the same quantities and frequencies as alternative 1, but with changes

in dredging methods, work window, and disposal location for silt. Mechanical dredging would still be the primary dredging method

used, but hydraulic dredging would also be considered for off-channel areas on a case-by-case basis. The majority of the dredging

would be done during the winter in- water work windows used in alternative 1, but a summer work window would be considered for

off-channel areas on a case-by-case basis. Silt would no longer be disposed of in deep-water sites. Instead, all dredged materials

would be placed in water to create shallow-water fish habitat that would be beneficial to salmonid species.

Disposal and creation of shallow-water habitat would be accomplished using bottom-dump barges to transport and deposit the

dredged material. Finer sands and silts would be used in a base for creation of habitat and may be dumped in mid-depth water

areas as part of this process. Coarser sands, gravels, and cobbles would be placed over the base or within shallow water. These

materials provide a favorable substrate for juvenile salmonid rearing and resting. Finally, a drag beam or some other similar device

would be used to re-contour the surface of the material dumped from the bottom-dump barges in order to provide a relatively

smooth surface. Placement and contouring of sand and gravel would occur with each dredging cycle in order to maximize the

amount of habitat created. Figures ES-2 and ES-3 illustrate this dredged material management process.

Figure ES-2. Cross Section of the Phased Development Disposal Techniques for Creating Shallow Water Habitat

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Figure ES-3. Shallow Water Sediment Placement Technique Using A Bottom Dump Barge

An upland containment area would be constructed for disposal of dredged materials that sediment testing indicates would be

unsuitable for in-water disposal but suitable for upland disposal. These dredged materials would be transported by barge to the

upland disposal site. Currently, the preferred site is the Joso HMU, located on land adjacent to the Lower Monumental reservoir at

Snake River Mile 56.5 (see plate 11). Only material that meets all applicable environmental health and safety regulations and

requirements would be disposed of at the upland site. Material that is not appropriate for disposal at the upland site would be

transported to a licensed landfill facility.

Alternative 2 would employ an "adaptive management" approach to the overall implementation of the DMMP. The Local Sediment

Management Group (LSMG) would provide input and feedback to the Corps with respect to dredging and dredged material

management that would be implemented under this alternative, as well as Alternatives 3 and 4. The adaptive management

approach would allow the Corps and the LSMG to regularly evaluate dredging and dredged material management activities and

monitoring results, and make needed adjustments to the overall course of action.

This alternative includes raising the levee at Lewiston up to 3 feet (0.9-m) at critical locations to maintain flow conveyance. Plate 18

shows the location of proposed levee raises. Proposed levee raises would require modification of portions of two adjacent roadways.

Three existing buildings would experience an increased risk of flooding.

Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

This alternative considers the same dredging activities in terms of locations, quantities, frequencies, and methods as alternatives 1

and 2, but with upland disposal of dredged material. The 3-foot (0.9-m) levee raise described as a part of alternative 2 would be

included with this alternative.

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Under this alternative, dredged materials would be transported by barge to the Joso upland disposal site (see plate 11). This site was

selected through a process that identified and screened multiple candidate sites and selected the Joso site based on environmental

and economic considerations. A large portion of the Joso site is a disturbed area that was previously used for gravel mining. An

existing barge slip is located at the downstream end of the site, and this area would be used to establish an off- loading and staging

area for the disposal facility. A containment berm would be constructed around the disposal area and a 600-foot (182.9-m) setback

from the river would provide a buffer zone to minimize environmental impacts of disposal operations.

Alternative 4 -Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

This alternative considers the same dredging activities in terms of locations, quantities, frequencies, and methods as alternatives 1,

2, and 3. As with alternatives 2 and 3, this alternative includes raising the levee at Lewiston up to 3 feet (0.9 m) at critical locations to

maintain the flow conveyance capacity of the upper reservoir behind Lower Granite Dam at the confluence of the Snake and

Clearwater Rivers.

The distinguishing characteristic of alternative 4 is that the primary focus of the management strategy for dredged material under

this alternative would be to incorporate beneficial uses. For each dredging activity, the Corps would identify potential beneficial uses

and coordinate the uses with the Local Sediment Management Group prior to selecting a use. Beneficial uses, as defined by this

process, may be achieved when a local sponsor is willing to contribute a share of the cost if the use would require cost sharing.

Potential beneficial uses that could be initially considered include:

Fish habitat creation as described in alternative 2.

Woody riparian habitat program.

Hanford remediation and closure activities capping material.

Potting soil.

Riparian habitat restoration.

Fill at Port of Wilma.

Fill on non-Federal lands.

Fill for roadway projects.

The Corps proposes to use dredged material to develop woody riparian area at Chief Timothy Habitat Management Unit in Lower

Granite Reservoir as a beneficial use of dredged material that would result from the planned dredging in winter 2002-2003. This

beneficial use would create shoreline habitat in line with the goals of the Lower Snake River Fish and Wildlife Compensation Plan.

Because opportunities to use dredged material beneficially become available over time and cannot always be anticipated, a process

would be established whereby a notice would be sent to parties known to have an interest in the use of the dredged material and a

public notice published prior to the proposed dredging/beneficial use activity. Impacts would be assessed on a case-by-case basis

through this process. The Corps may prepare Biological Assessments (BA's) for each dredging activity or for up to 5 years of

dredging activities, depending upon the outcome of the Endangered Species Act (ESA) consultation processes with the NMFS and

U.S. Fish and Wildlife Service (USFWS). The Corps may also prepare a Clean Water Act Section 404(b)(1) evaluation for each

dredging activity or for 5 to 10 years of dredging, depending upon the outcome of coordination with the state water quality agencies

and EPA.

ENVIRONMENTAL EFFECTS OF ALTERNATIVES

The following sections provide brief summaries of the anticipated environmental effects of the plan alternatives considered in the

DMMP/EIS for each element and table ES-2 presents a summary of those effects. The anticipated effects are generally

characterized with respect to their intensity and duration as:

Direct, indirect, or cumulative;

Minor, moderate, or major, and

Short- or long-term.

Table ES-2

Environmental Effects Summary Matrix

Discipline

Alternative 1

No Action (No Change) -

Maintenance Dredging,

With In-Water Disposal

Alternative 2

Maintenance Dredging

With In-Water Disposal

To Create Fish Habitat

Alternative 3

Maintenance Dredging

With Upland Disposal

And A 3-Foot (0.9-m)

Alternative 4

Maintenance Dredging

With Beneficial Use

Of Dredged Material

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And A 3-Foot (0.9-m)

Levee Raise Levee Raise

And A 3-Foot (0.9-m)

Levee Raise

Aquatic Resources

Direct and indirect, minor,

short-term effects on food

source for aquatic species.

No long-term effects

anticipated. Potential

beneficial effects from

creation of some in-water

fish habitat.

Direct and indirect, minor,

short-term effect on food

source for aquatic species.

No long-term effects

anticipated. Potential

beneficial effects (greater

than Alternative 1) from

creation of shallow water

fish habitat.

Direct and indirect, minor,

short-term effect on food

source for aquatic species.

No long-term negative

effects anticipated. No

creation of in-water fish

habitat.

Direct and indirect, minor,

short-term effect on food

source for aquatic species;

no long-term negative

effects anticipated.

Potential beneficial effects

from creation of shallow

water fish habitat and/or

beneficial use that may

restore habitat.

Terrestrial

Resources

Indirect, short-term minor

effects on terrestrial

wildlife and habitat.

Similar effects as

Alternative 1: Minor,

short-term, indirect

impacts on terrestrial

species through disruption

of habitat from levee raise

and displacement during

dredging.

Direct, moderate effects to

terrestrial species from

loss of habitat at upland

disposal site and

disruption of habitat from

levee raise. Positive effects

from habitat creation in old

borrow area at disposal

site.

Indirect, minor, short-term,

negative effects through

disruption of habitat from

levee raise; potential

long-term positive effects

from beneficial use of

dredged material to create

upland habitat and woody

riparian habitat.

Endangered

Species

Fish - "May affect

and would likely

adversely affect"

salmonids but no

jeopardy to listed

species; "may affect,

not likely to affect"

bull trout.

Terrestrial Wildlife -

"May affect, not likely

to adversely affect"

bald eagle.

Plants - "May affect,

not likely to

adversely affect" Ute

ladies' tresses and

water howellia; " no

effect" on Spalding's

silene.

Same effects as

Alternative 1.

Same effects as

Alternative 1.

Same effects as

Alternative 1.

Recreation

Minor, short-term impact

on access to portions of

the river for recreational

boats near proposed

dredging and disposal

activities. Maintains ability

to use recreational

facilities.

Minor, short-term, direct

impact due to disruption of

recreational facilities in

Lewiston area due to levee

raise, and minor

short-term impact to

recreational boating near

dredging and disposal.

Maintains ability to use

recreational facilities.

Same effects as

Alternative 2 except for

dredged material disposal.

Minor indirect effects to

recreational users in the

vicinity of the upland

disposal. Maintains ability

to use recreational

facilities.

Same effects as

Alternative 2. Potential

long-term, beneficial effect

from beneficial use of

dredged material if used to

enhance recreation sites.

Maintains ability to use

recreational facilities.

Cultural

Resources

Known submerged

cultural properties would

be avoided to the

maximum extent

practicable during

dredged material disposal

and management

activities.

Same effects as

Alternative 1.

Same effects as

Alternative 1. Cultural

properties in vicinity of

upland disposal site would

be avoided.

Same effects as

Alternative 1. Potential

long-term beneficial uses

would be evaluated as

proposals are developed.

Socioeconomics

Long-term, positive effect

from maintaining

navigation. Indirect,

long-term, moderate

negative effect from

greater potential flood risk

(no levee raise). Minor

Long-term, positive effect

from maintaining

navigation. Direct,

short-term and long-term

positive effect from levee

raise due to added jobs

and materials required by

Same effects as

Alternative 2.

Same effects as

Alternative 2.

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effects could occur.

Low-income and minority

populations not

disproportionately

affected.

levee construction.

Reduction of flood risk

from levee raise.

Low-income and minority

populations not

disproportionately

affected.

Transportation Maintains existing

transportation systems.

Direct, short-term, minor

effect on roadways from

proposed levee/road raise

construction activities.

Same effects as

Alternative 2.

Same effects as

Alternative 2. Potential

positive effect if dredged

material is used for

transportation projects.

Geology and Soils Local displacement of soil

and alluvial material.

Potential short-term effect

to soils in the vicinity of

levee raise due to

construction activities.

Potential short-term effect

to soils in the vicinity of

levee raise. Long-term

effects on soils at upland

disposal site due to

construction and disposal

activities.

Potential short-term effect

to soils from

implementation of

beneficial use due to

construction activities.

Water

Quality/Water

Resources

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity.

Wetlands - No effect.

Flood Plains - No

impacts.

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity.

Wetlands - No direct

effect. Minor indirect

effects associated

with levee raise.

Flood Plains - Minor,

short-term impact at

proposed upland

containment site.

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity.

Wetlands - No direct

effect. Minor, indirect

effects associated

with levee raise and

upland disposal.

Flood Plains - Minor,

short-term impact at

upland disposal site.

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity, and

placement of fill in

shoreline areas for

woody riparian

habitat creation.

Wetlands - Minor

direct effect from

woody riparian

habitat creation

adjacent to wetland.

Minor indirect effects

associated with levee

raise.

Flood Plains - No

impact to floodplain

from woody riparian

development. Future

beneficial uses may

require assessment

of floodplain

impacts.

Hazardous, Toxic,

and Radioactive

Waste

No effects anticipated;

sediments will be tested

for contamination.

Same effects as

Alternative 1.

Same effects as

Alternative 1.

Same effects as

Alternative 1.

Air Quality

Direct, minor, short-term

effects to local air quality

due to dredging and

disposal equipment

operation.

Direct, minor, short-term

effects to local air quality

due to dredging, disposal,

and construction

equipment operation.

Direct, minor, short-term

effects to local air quality

due to dredging, disposal,

and construction

equipment operation and

upland disposal activities.

Direct, minor, short-term

effects to local air quality

due to dredging, disposal,

and construction

equipment operation,

including implementation

of beneficial use(s).

Noise

Direct, minor, short-term

effects due to noise from

dredging and disposal

equipment operation.

Same effects as

Alternative 1. Localized

minor, short-term noise

from construction levees.

Same effects as

Alternative 1. Localized

minor, short-term noise

from construction levees.

Same effects as

Alternative 1. Localized

minor, short-term noise

from construction levees.

Aesthetics

Direct, minor, short-term

effects on aesthetics from

dredging and disposal

activities.

Direct, minor, short-term

effects on aesthetics from

dredging and disposal

activities; long-term, minor

impacts from levee raise.

Direct, minor, short-term

effects from dredging.

Long-term, minor impacts

from levee raise. Direct,

minor, long-term effects

from upland disposal.

Direct, minor, short-term

effects from dredging and

disposal; long-term, minor

impacts from levee raise;

and long-term beneficial

effect to shoreline area for

woody riparian habitat

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creation.

Native American

Tribal

Communities

Potential positive effects

on salmon fishing from

creation of salmon rearing

habitat and cultural

resources to be avoided.

Potential positive effects

(greater than Alternative 1)

on salmon fishing from

creation of salmon rearing

habitat.

No effects anticipated. Same effects on salmon

fishing as for Alternative 2.

Cumulative Effects

Potential positive effects

on salmonid fish from

creation of shallow-water

fish habitat. Other

resources were evaluated

regarding cumulative

effects and nothing was

determined to preclude

the selection of this

alternative.

Potential positive effects

on salmonid fish (greater

than Alternative 1) from

creation of shallow-water

fish habitat. Same effects

on other resources as

Alternative 1.

Potential positive effects to

terrestrial species from

filling old borrow area at

disposal site and

establishing vegetation.

Same effects on other

resources as Alternative 1.

Same effects as

Alternative 2. Positive

effects from proposed

beneficial use of dredged

material (e.g., woody

riparian habitat

development). Same

effects on other resources

as Alternative 1.

1

"Impacts" and "effects" are used interchangeably. Unless otherwise noted as beneficial or positive, impacts described are negative.

Aquatic Resources

The dredging activity associated with all four alternatives would have the same indirect, minor, short-term effects on aquatic

ecosystems by disturbing sediments and removing macroinvertebrate species (which are prey species for resident and migratory

fish) from the dredging area. However, re-colonization of macroinvertebrates would occur relatively rapidly within both the dredging

area and at the in-water shallow and mid-depth disposal areas. Long-term impacts would not occur. Fish could use the areas

upstream and downstream of dredging and disposal activities, and dredging would not be a continuous activity confined to a single

location. Fish could return to the area following completion of dredging and disposal activities.

Alternatives 1, 2, and 4 could have potential benefits by creation of in-water fish habitat, whereas alternative 3 (upland disposal)

would provide no benefit to fish habitat. In addition to benefiting salmonid species, creation of in-water habitat could benefit white

sturgeon and macroinvertebrate species. Initially, the proposed beneficial use would be creation of woody riparian habitat in

shoreline areas of Chief Timothy HMU. The 3-foot (0.9-m) levee raise proposed in alternatives 2, 3, and 4 would have no impacts on

aquatic resources.

Terrestrial Resources

The dredging and disposal actions within and adjacent to the river included in alternatives 1 through 4 would not prevent wildlife

(primarily waterfowl and raptors) from obtaining food from, or otherwise using the areas adjacent to, dredging and disposal activities.

Dredging and disposal activities would occur only within the approved in- water work window and, following dredging and disposal,

wildlife would return to areas affected by these activities.

There would be displacement of wildlife habitat for alternative 3, where the disposal of all dredged material would occur at the Joso

upland site. Most disposal activities would occur on the disturbed portion of the site that was formerly used as a gravel pit. The area

would be stabilized following each disposal cycle and would be re-contoured and restored with native plantings following

completion of all dredging over the next 20 years. With completion of the disposal and revegetation, the site would provide wildlife

habitat similar to the surrounding area, which would be a long-term benefit to wildlife habitat. Upland disposal at Joso is expected to

have a direct, long-term, moderate impact on terrestrial wildlife. Material that is unsuitable for in-water disposal under alternatives 2

and 4 would be taken to an upland site (currently identified as the Joso site), which would have a minor, direct effect on terrestrial

resources at the site.

The proposed 3-foot (0.9- m) levee raise for alternatives 2, 3, and 4 would similarly have minor, indirect, temporary impacts on

terrestrial species. Construction could disturb wildlife; however, the areas proposed for the levee raise are in an urban setting and

only those species accustomed to human activity would be present. The levee raise would be placed atop the existing levee.

Revegetation would result in habitat similar to existing conditions.

Endangered Species

The Corps prepared a Biological Assessment for the proposed dredging and dredged material management activities and consulted

with NMFS and USFWS. See Appendix F and G for further details. NMFS determined that the proposed actions would not cause

jeopardy to anadromous fish species listed under the Endangered Species Act (ESA) and set forth Reasonable and Prudent

Measures. USFWS provided concurrence with the findings of the Corps’ Biological Assessment.

Anadromous salmon and steelhead stock from all of the Evolutionary Significant Units (ESU's) listed as Threatened or Endangered

under the ESA pass through the McNary reservoir and lower Snake River. These species include Snake River spring/summer

chinook salmon (Oncorhynchus tshawytscha), listed as Threatened in 1991; Snake River fall chinook salmon (O. tshawytscha), listed

as Threatened in 1991; Snake River sockeye salmon (O. nerka), listed as Endangered in 1992; Snake River Basin steelhead (O.

mykiss), listed as Threatened in 1998; Upper Columbia River spring run chinook salmon (O. tshawytscha), listed as Endangered in

1999; Middle Columbia River steelhead (O. mykiss), listed as Threatened in 1999; and Upper Columbia River steelhead, listed as

Endangered in 1997. In addition, the resident Columbia Basin bull trout (Salvelinus confluentus) is listed as Threatened under the

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ESA.

Of the alternatives that involve in- water disposal, alternative 1 would provide the least benefit to increasing habitat for fall chinook

salmon rearing in the McNary and lower Snake River reservoirs. The dredged material disposal methods of alternative 2 would

provide the greater opportunity to develop shallow water salmonid habitat throughout the McNary and lower Snake River reservoirs.

Upland disposal of dredged material proposed in alternative 3 would not provide for creation of salmonid habitat. Some of the

beneficial uses proposed in alternative 4 could also create salmonid habitat.

Because dredging and disposal activities would only occur dur ing authorized in-water work windows, impacts to salmonids would

be minimized. For alternative 1, the work windows would be winter only. For alternatives 2, 3, and 4, these work windows would

include winter main stem dredging and both winter and summer dredging of off-channel areas.

The likelihood of bull trout being in the project areas is remote, and they are not expected to be affected by the dredging and

disposal activities. However, if bull trout were present in dredging and disposal areas, there would be short-term, indirect effects due

to turbidity and disturbance from dredging activities, which would cause them to leave the area.

Beneficial use of dredged material proposed in alternative 4 is anticipated to have minor effects or potential benefits to endangered

fish species.

The bald eagle (Haliaetus leucocephalus) inhabits the project area and is listed as Threatened under the ESA. The dredging

activities proposed for all four alternatives would not be a continuous activity confined to a single location. If impacts to bald eagles

were to occur, they would be minor, short-term, and localized. Adjacent areas would be available for foraging, feeding, and

perching.

The levee raise proposed in alternatives 2, 3, and 4 would not result in the loss of any trees or shoreline perch areas. Eagles’ prey

species would not be impacted. Thus, if any impacts were to occur, they would be related to disturbance during construction and

would be minor, short-term, and localized.

Two plant species that may be found within the project area [Ute ladies’ tresses (Spiranthes diluvialis) and water howellia (Howellia

aquatilus)] are listed as Threatened under the ESA. Another plant, Spalding's silene, is proposed for listing under the ESA.

The proposed activity would not likely impact these plant species. There are no recorded observations of Ute ladies’ tresses in the

project vicinity, and they are not likely to occur due to lack of suitable habitat and the elevation of the project area. Therefore, no

impacts to Ute ladies’ tresses are expected to occur. Similarly, water howellia and Spalding's silene are not likely to occur at this low

elevation or in this habitat.

As with endangered fish species, alternative 4 is not anticipated to impact endangered terrestrial species. However, because

opportunities to use dredged material beneficially become available over time and cannot always be anticipated, a process has been

established whereby a notice would be sent to parties known to have an interest in the use of the dredged material and a public

notice published prior to the dredging activity. Impacts would be assessed on a case-by-case basis through this process. Plant

surveys would be required to determine the presence of Ute ladies’ tresses. Any sites found to support these plants would need to

be avoided to preclude impacts to these plants. A BA may be prepared for each dredging activity, or for 5 years of dredging

activities, depending upon the outcome of the ESA consultation with USFWS.

Recreation

Dredging activities proposed as part of all of the alternatives are expected to have a minor, short-term effect on those recreation

activities and facilities located near proposed dredging and disposal locations. Dredging scenarios proposed may temporarily close

boat ramps and boat basins and affect public recreation areas (e.g., swimming beaches) on a short-term basis during maintenance

dredging. There would be short-term, minor impacts due to low levels of activities that occur during the winter months. Summer

dredging of recreation sites would also have short-term impacts since the small areas would not take long to dredge. Construction

of the levee raises proposed under alternatives 2, 3, and 4 are anticipated to have short-term, direct effects on the Lewiston levees

park and the recreational activities that occur there. These effects would be minor because they impose a temporary disruption of

activities at the Lewiston levees park, specifically multi- use paths and day- use facilities such as picnic tables on and adjacent to

the levees could not be used during construction of the levee raise. Recreational facilities and activities would be restored following

the interruption caused by the construction of the levee raise.

Upland disposal activities (barging and material handling) at the Joso site would have long-term, minor, indirect effects on river

users, hunters, and the nearby Lyon’s Ferry State Park and Lyon’s Ferry Marina facilities. These effects are anticipated to be minor

since the disposal area is set back at least 600 feet (182.9 m) from the river shoreline and is not directly visible from Lyon’s Ferry

State Park and Lyon’s Ferry Marina, which are located on the opposite side of the Snake River.

To the extent that beneficial uses of dredged material would reduce the need to dispose of the material either upland or in-water,

these uses are expected to have minor, direct impacts to recreational facilities and activities, depending on where the material is

placed. Beneficial uses that would create or enhance wildlife habitat would have indirect beneficial effects on recreation if they

enhanced hunting, fishing, or wildlife viewing opportunities.

Cultural Resources

Proposed dredging, disposal, and levee modification activities could affect cultural resources located within the project's area of

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potential effect as defined under the National Historic Preservation Act (NHPA). Dredging actions for all four alternatives would be

limited to the removal of accumulated sediments and would not affect original riverbed or shoreline material, or cultural resources

contained within that material. In-water disposal proposed in alternatives 1, 2, and 4 could affect identified underwater cultural

resources in the lower Snake River and McNary reservoirs; however, known submerged cultural resource sites would be avoided to

the maximum extent practicable during the placement of dredged material. Levee modification proposed in alternatives 2, 3, and 4

would not affect any cultural resources sites that have been ident ified.

Alternatives 2, 3, and 4 would use the Joso area for the upland disposal of some or all of the dredged material. Any cultural

resources identified in the vicinity of the Joso upland disposal site would be avoided during construction and operation of the

disposal site.

Beneficial uses of dredged material, as proposed in alternative 4, could potentially affect cultural resources, depending on the use.

Prior to implementation of any beneficial use, the Corps would need to conduct research and field investigations to determine if

cultural resources would potentially be affected.

The development, implementation, and monitoring of project actions would be conducted in conformance with the NHPA and the

National Environmental Policy Act. Prior to the finalization and implementation of any plan, the Corps would complete the required

cultural resource consultation. The Corps would continue to consult with appropriate State and Tribal Historic Preservation Officer(s)

as well as other affected consulting parties throughout the life of the 20-year plan.

If human remains were inadvertently discovered during dredging or dredged material handling operations, all work in the immediate

area would stop and the Corps archaeologist will take the appropriate steps to address the discovery. The Corps will notify all

appropriate tribes, agencies, and local coroner’s offices depending on the status of the human remains.

Socioeconomics

Dredging to maintain the navigation channel, access channels to ports and moorages, public recreation areas, irrigation intakes for

HMUs, and flow conveyance capacity of the Lower Granite reservoir proposed under all four alternatives, and disposal of dredged

material in- water proposed in alternatives 1, 2, and 4 represent no change in the management of the navigation projects and

associated facilities. Therefore, with respect to navigation and economic use of waterways, these alternatives would have no effects

on regional population, employment, or income. All alternatives considered would have minor, short-term, positive economic effects

due to added employment for dredging-related activities.

Since alternative 1 does not include a levee raise in Lewiston, allowing continued loss of levee freeboard and increased risk

associated with flooding, it would be expected (in comparison to the other alternatives being considered) to have an indirect,

long-term, moderate negative effect on the local economy of the Lewiston area since reduction in annualized flood damages would

not be realized. Proposed levee modifications for alternatives 2, 3, and 4 are anticipated to have a direct, short-term, positive effect

on the local economy of the Lewiston area due to the added jobs and materials required for construction of the levee modifications.

Upland disposal proposed under alternative 3 would be expected to have a direct, minor, short-term positive impact due to jobs

created for construction and initial operation of the disposal facility at the Joso site. The economic effects would remain positive, but

lessen over time, for the continued use of the upland disposal facility.

Beneficial use of dredged material would be expected to have a direct, minor, short-term positive economic effect due to

construction activities associated with implementation of the beneficial use. Also, beneficial uses that create or enhance wildlife

habitat or recreational resources would potentially have minor, indirect, long-term beneficial effects attributable to enhancement of

recreational resources and opportunities.

The Corps reviewed demographic data to identify areas where there are potential environmental justice populations, and considered

the alternatives’ environmental effects with respect to these areas.

Transportation

River Navigation

Maintenance dredging for all four alternatives would have a long-term beneficial impact on river navigation by ensuring adequate

depths in the navigation channels, access channels to ports and moorages, and public recreation areas. In-water disposal activities

would be away from areas of commercial navigation. Dredging in the navigation channels would occur on a 2-year cycle on average,

causing some disruption during the authorized in- water work period from December 15 to March 1 in the Snake River and

December 1 and March 31 in the Columbia River. No disruption to recreational boating would be expected in the main river

channels; only short-term disruption may occur during maintenance dredging of boat basins.

Upland disposal of all material proposed in alternative 3 would increase the number of lockages (barges passing through lock and

dam facilities) during the dredging period by as much as 150 lockages every 2 years (up to 113 barges with an average of four

lockages of three barge tows). These lockages would occur during a time of year when they would cause very little impact to other

commercial or recreational traffic.

Alternative 4 could have different effects in the disposal area depending on the disposal location and method employed to develop

the beneficial use. For the beneficial uses being considered, the adverse impacts to other river navigation would be short-term and

minor. In some cases beneficial uses could have positive impacts to river navigation by providing added terminal and port areas.

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Railroads

Continued maintenance of the navigation channels, access channels to ports and moorages, public recreation areas, irrigation

intakes, and flow conveyance capacity proposed in all four alternatives would have no adverse effect on the railroads in the area

and would continue to support the multi- modal flow of commerce to and from the study area.

The nominal 3- foot (0.9- m) levee raise, proposed in alternatives 2, 3, and 4 includes construction to the west levee below the south

abutment of the Camas Prairie Railroad Bridge over the Clearwater River at Lewiston and would have minor, short-term impacts

during construction.

Disposal of all dredged material at Joso proposed in alternative 3 would cause minor, long-term, direct impacts to the Union Pacific

Railroad resulting from the developments of the Joso disposal site and increases in crossings of the Union Pacific Railroad rightof-way during construction.

The beneficial use of the dredged material proposed in alternative 4 would be determined on a case-by-case basis and may affect

the railroads due to minor disruptions that could potentially involve the railroad to transport dredged material to a final destination

point. The potential impacts to railroads from this alternative are expected to be minor.

Highways/Roadways

Modification of roads (associated with the levee raise) proposed in alternatives 2, 3, and 4 would create short-term, direct impacts to

Highway 129 and the Snake River Road. The roadways would be raised to avoid inundation with water during high- flow events.

Effects would occur during reconstruction of the affected portions of roadway.

One concept for beneficial use of dredged material, proposed in alternative 4, would use the material to form a roadway connection

on the north shore of the Lower Granite pool linking State Route (SR) 193 at Wawawai to SR 194, a distance of 3 miles [4.8

kilometers (km)]. This would create a potential positive effect with respect to roadway construction.

Geology and Soils

Maintenance dredging proposed in all fo ur alternatives is not anticipated to significantly affect the geology and soils in areas

surrounding the lower Snake River and McNary reservoirs. Dredging would cause local soil and rock disturbance and relocation of

some alluvial material.

Modifications to the levee system in Lewiston proposed in alternatives 2, 3, and 4 are expected to result in direct effects on the

geology and soils of the levees and surrounding areas. Minor, short-term effects to soils and topography, resulting from

earthmoving and construction activities, are expected during construction of the levee modifications.

Upland disposal as proposed under alternative 3 is anticipated to have a direct, long-term effect on the soils and topography of the

Joso site. Erosion and compaction would occur from construction and dredged material disposal activities. Site restoration would

include stabilizing and seeding of the dredged material after it has been disposed of on site. Disposal material would be contained

within a bermed area and drainage would be controlled to minimize erosion. In addition, a 600- foot (182.9- m) setback from the river

would help minimize shoreline erosion.

Alternative 4 would use some or all of the dredged material for beneficial uses. Beneficial uses, such as woody riparian habitat

creation, other habitat creation/enhancement, landfill cover, or other activities, would be expected to have direct, short-term impacts

to the soils in the areas where the uses would be implemented.

Water Quality/Water Resources

All alternatives considered in the DMMP/EIS are expected to have a temporary, direct negative effect on water quality in the

Columbia, Snake, and Clearwater Rivers, mostly because of turbidity plumes caused by the dredging and, where proposed, inwater disposal. However, it is anticipated that elevated turbidity levels would be confined and will stay within the "mixing zones"

(established under Clean Water Act Section 401 water quality certification) allowed for this activity, and allowable turbidity

downstream of the mixing zone would not be exceeded.

Historically, the Corps has sampled and tested dredged materials for sediment size and quality, including contaminants, to

determine suitability for in-water disposal. To date, sediment contaminant levels have been at low levels that allow in- water

disposal. Based on historic sediment testing data, contaminant levels that would preclude in-water disposal in the future are not

anticipated. Nonetheless, the Corps will continue its sediment sampling protocols to ensure sediment quality is adequately

assessed.

Construction of the levees at Lewiston proposed in alternatives 2, 3, and 4 could result in short-term, minor water quality impacts

due to runoff and erosion. These concerns would be minimized with the implementation of a site-specific Erosion/Sedimentation

Control (ESC) Plan and construction best management practices (BMP's). The levees would be stabilized by hydroseeding

immediately after construction.

Direct, temporary, minor impacts due to erosion may occur as a result of construction and disposal operations at the Joso site as

proposed in alternative 3. A containment berm would be constructed on the perimeter of the permanent disposal area and would

minimize water quality impacts associated with runoff and erosion. An ESC plan would be developed and BMP's used during site

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development. The site would also be regularly stabilized in a phased manner during disposal, and measures will be taken to

minimize sedimentation from dredged material transfer activities.

Impacts from beneficial use of the dredged material proposed in alternative 4 could vary depending on the use and would be the

responsibility of the local sponsor. As with other dredged material management methods, beneficial uses involving placement of

dredged materials would be subject to ESC measures and BMP's.

Wetlands

Minor, short-term, indirect impact to wetlands adjacent to the levees or roadway could occur during construction of the nominal 3-

foot (0.9- m) levees as proposed in alternatives 2, 3, and 4. Long-term impacts are not expected as a result of the levee raise.

Two small wetland areas have been identified in the vicinity of the Joso upland disposal site proposed in alternative 3. The proposed

disposal facility has been sited to avoid directly or indirectly affecting these wetland areas.

Beneficial uses proposed in alternative 4 would be expected to generally affect wetland resources positively if dredged material were

used for enhancement or creation of aquatic and wildlife habitat. Beneficial uses could potentially improve wetland size, function,

and quality. Specific wetlands in the vicinity of a proposed beneficial use would require identification prior to commitment for the

beneficial use project. A wetland area approximately one acre (0.4 hectare) in area is adjacent to the area where woody riparian

habitat development is proposed. This wetland area would be minimally impacted by the proposed habitat development. The

wetland is a low area where ponding occurs; it holds water only at extremely high pool elevations, and dries out during most years.

Under the proposed beneficial use, an inlet channel to the pond would be constructed, which should increase flows into the pond at

lower reservoir elevations. It will also have an exit (outlet) constructed so there will be some flow through, thus improving the water

quality.

Floodplains

There would be no foreseeable significant negative floodplain impacts as a result of the maintenance dredging proposed in all four

alternatives or the levee raise at Lewiston proposed in alternatives 2, 3, and 4.

The permanent upland disposal site at Joso would not be located in the 100-year floodplain and would not affect the floodplain.

Approximately 360,000 square feet (33 445.1 square meters) of the unloading and temporary storage area for dredged material

would encroach on the 100-year floodplain, causing minor short-term impacts to the floodplain during the time that the material is

stored. However, the fill is not expected to change the water surface elevation and would not pose long-term effects on the 100-year

floodplain.

Beneficial uses are not anticipated to present significant impacts to floodplain areas. The proposed woody riparian habitat creation

would involve placement of fill in shoreline areas at Chief Timothy HMU, including some areas within the 100-year floodplain. This fill

would not change the water surface elevation, nor have impact on the 100-year floodplain. Specific areas considered for placement

of dredged material under beneficial use would require analysis of floodplain issues.

Hazardous, Toxic, and Radioactive Waste

Based on Phase I environmental site assessments conducted for the Joso site, there is a very low potential for land-based

hazardous, toxic, and/or radioactive waste concerns to be associated with the Joso upland disposal site.

Based upon existing sediment quality data, it is not anticipated that the handling and disposal of dredged materials as hazardous or

solid waste (as defined by applicable environmental health and safety regulations and requirements) would be required.

The proposed woody riparian habitat creation area at Chief Timothy HMU does not pose any known HTRW concerns. Beneficial use

of dredged materials could have minor positive effects on hazardous waste if dredged material was used for cover or fill at the

Hanford Reservation, which is a beneficial use option considered in alternative 4. In general, beneficial uses that involve upland

handling of dredged materials would not be expected to have hazardous waste effects, given the quality of the sediments. See the

Water Quality/Water Resources section for information on sediment contaminant levels.

Because of the location of the Hanford Nuclear Reservation at the upstream end of McNary reservoir, there is speculation of

radioactive materials being present in the reservoir sediments. Dredging activities under any of the four alternatives should not

extend deep enough into the sediment layer to reach existing (if any) radioactive material. However, the Corps plans to evaluate

each dredging activity in the McNary reservoir and determine if and what type of further pre-dredging sediment testing and analysis

may be necessary.

Air Quality

All alternatives would cause direct, minor, short-term effects to local air quality due to dredging equipment operation. Dredged

material would be wet, and is not anticipated to be subject to dust generation. Construction activities associated with raising the

Lewiston levee could generate dust, as could the upland disposal at Joso proposed in alternative 3 and the upland contingency

disposal at Joso in alternatives 2 and 4. The BMP's would be used to prevent material from becoming airborne during transport,

offloading, and upland placement.

No additional impacts associated with implementation of alternative 4 are anticipated.

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Noise

Minor, direct, short-term noise impacts are anticipated to result from dredging, transport, and disposal activities of all alternatives

considered. Levee construction would occur primarily during daytime hours and would cause minor, short-term impacts from

construction activities. Upland disposal of dredged material would occur primarily during daytime hours and would have minor,

direct, short-term effects during site work and disposal activities.

Aesthetics

It is anticipated that all four alternatives will have a direct impact on aesthetics in the area where dredging activities are taking place

and, for alternatives 1, 2, and 4, where in-water disposal is anticipated. Impacts due to levee modification as proposed in alternatives

2, 3, and 4 are expected to be both short-term (due to construction activities) and long-term (due to raising of the levees). Levee

modifications would affect the riverfront park facilities and would present moderate impacts to both visual quality and viewing

patterns.

Under alternative 3, dredged material from all reservoirs disposed of at the Joso site in the Lower Monumental reservoir would have

a direct, long-term effect on the aesthetics of the disposal site and the areas immediately surrounding the site from which the site

can be viewed. While the proposed disposal operations would directly impact the aesthetic quality of the Joso site, the effects would

be minor due to the fact that the site is not highly visible to viewers and would be restored upon completion of disposal operations.

Beneficial use of dredged material, proposed in alternative 4, would potentially have a long-term positive effect on aesthetic

resources if used for wetlands or habitat restoration. Proposed woody riparian habitat creation at Chief Timothy HMU in Lower

Granite Reservoir would have a long term, beneficial effect on the aesthetics of the shoreline area.

Native American Tribes and Communities

Impacts from DMMP activities that are of concern to tribes would involve potential effects to aquatic species and their habitats, water

quality, and cultural resources. Although DMMP actions would occur in the five study area reservoirs over its 20-year life, most

dredging activities and the majority of any in-water disposal would occur in the Lower Granite reservoir.

Dredging as proposed for alternatives 1, 2, 3, and 4, and in- water disposal of dredged materials as proposed for alternatives 1, 2,

and 4, could result in habitat changes that are beneficial, neutral, or even detrimental to different aquatic species depending on

given species responses and needs. Constructing more shallow-water habitat could change water quality factors. Shallow-water

temperatures, currently below optimum for the growing season of resident game fish, would be increased and possibly enhance

resident game fish habitat conditions and population numbers.

Water quality impacts from DMMP activities under any of the alternatives are expected to be temporary, but would result in direct

negative effects due to turbidity plumes caused by dredging and in-water disposal. Greater sediment plumes are expected from

dredging operations.

Concerns over potential impacts to cultural resources would be focused on damage to cultural sites from dredging actions or

covering sites with too much sediment as a result of disposal activities. As now planned, dredging under all four alternatives would

be limited to existing navigation channels and/or would not go below accumulated sediments into original riverbed. Likewise,

disposal activities either upland or in- water would avoid known sites. (However, sediment drift from in- water disposal could result in

the eventual covering of sites with additional material.) Such actions would help to reduce the chances of impacting cultural sites.

Cumulative Effects

The National Environmental Policy Act and the Council on Environmental Quality’s regulations require Federal agencies to consider

the cumulative impacts of their actions on the natural and human environment. Cumulative effects are those environmental

consequences that result from the incremental impact of a proposed action when added to other past, present, and reasonably

foreseeable future actions, regardless of the agencies or individuals that may undertake them.

Other past, present, and reasonably foreseeable projects or actions that could, when added to the proposed plan alternatives,

result in cumulative impacts include:

Construction of the five Corps dams.

Land uses in the study area.

Past and present dredging and disposal activities undertaken by the Corps for navigation maintenance or flow conveyance, as

well as dredging for ports and/or boat basins within the study area.

Levee construction and modification.

Re-licensing of dams within the Columbia/Snake River system.

The Lower Snake River Juvenile Salmon Migration Feasibility Study.

Columbia River Channel Improvement Project.

The Corps has conducted a series of studies to evaluate appropriate in- water and upland disposal sites for dredged material and

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the effectiveness of habitat creation with dredged material deposited in water in shallow and mid-depth areas. In addition, the Corps

reviewed and considered major projects and plans from throughout the study area, both within and outside of their jurisdiction.

Plan alternatives considered in combination with past and present dredging and disposal activities and other reasonably foreseeable

plans and projects are not anticipated to cumulatively adversely affect the resources analyzed in the DMMP/EIS. The in-water

disposal to create juvenile salmonid rearing habitat, when coupled with other measures being taken by the region to improve fish

passage, may have a positive effect on juvenile salmonid survival.

RECOMMENDED PLAN/PREFERRED ALTERNATIVE

The Corps’ preferred alternative, or Recommended Plan, for long-term management of dredging is "Alternative 4 - Maintenance

Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise." Alternative 4 most completely and efficiently

meets the project purpose and need at the least cost, while presenting potential environmental impacts that are no greater, and

often less, than other alternatives considered.

The recommended plan also represents the greatest beneficial use of dredged material that can be implemented on a programmatic

basis at this time. Furthermore, the plan incorporates an adaptive management approach that provides for on- going evaluation of

proposed dredging and dredged material management activities and opportunities to adapt and adjust actions based on these

evaluations. Alternative 4 provides the most flexibility for identifying, evaluating, and potentially implementing beneficial uses of

dredged material. The plan becomes the basis for cost sharing of other beneficial uses of dredged material that may be identified in

the future as each separate dredging activity is planned and executed. Beneficial uses of dredged material may be adopted on a

case-by-case basis under this plan as opportunities become available and, if necessary, when local sponsors agree to fulfill

sponsorship requirements. To continue to optimize the use of dredged material, the Corps will coordinate potential beneficial uses

for each dredging activity with the LSMG prior to the start of dredging. Figure ES-4 displays the decision tree that the Corps would

use to determine the type of dredging and the disposal plan for each activity.

Figure ES-4. Disposal Site Selection Decision Tree

The 3-foot (0.9-m) levee raise feature is the preferred plan for maintaining the flow conveyance capacity in the Snake and

Clearwater Rivers confluence area of Lower Granite reservoir because it meets the purpose and need and produces maximum net

benefits in excess of costs. Raising the levee was found to reduce the need for dredging in the confluence area of Lower Granite

reservoir and, therefore, is considered as a part of this DMMP. Selection of the levee raise as the preferred flow conveyance

restoration method was based on the maximization of net benefits determined from a risk-based flood damage assessment and

annual costs amortized over the remaining 74 years of the project life. Levee construction would not start until after 2005 and after

any necessary appropriation and authorization is obtained.

Dredging projects implemented under this DMMP can be initiated in response to a variety of conditions described in the discussion

of the Local Sediment Management Group above.

The Corps has identified the first dredging activity that would be conducted under the DMMP. This dredging is currently proposed

for winter 2002-2003 and includes dredging the navigation channel at the confluence of the Snake and Clearwater rivers, several

port facilities in the Lewiston-Clarkston area, several recreation facilities in Lower Granite and Little Goose reservoirs, navigation lock

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approaches to Lower Granite and Lower Monumental Dams, and several other potential areas. The Corps is currently proposing

using dredged material to develop woody riparian habitat at the Chief Timothy Habitat Management Unit and/or using in-water

disposal to create fish habitat in Lower Granite reservoir as the beneficial use of the dredged material. Appendix N provides a

detailed description of the proposed dredging areas, the disposal plan, the sediment contaminant analysis, and the environmental

impacts specific to this dredging activity.

Section 1

Introduction

This Dredged Material Management Plan/Environmental Impact Statement (DMMP/EIS) presents the U.S. Army Corps of Engineers’

Walla Walla District (Corps') programmatic plan for:

Maintenance of the authorized navigation channel in the lower Snake River reservoirs between Lewiston, Idaho, and the

Columbia River, and McNary Lock and Dam (McNary) reservoir on the Columbia River for 20 years after the Record of Decision

(ROD) is signed.

Maintenance of limited public facilities within the reservoirs, such as recreational boat basins and irrigation intakes for the

wildlife habitat management units (HMUs).

Management of dredged material from these reservoirs.

Maintenance of flow conveyance capacity at the most upstream extent of the Lower Granite Lock and Dam (Lower Granite)

reservoir for the remaining economic life of the project (to year 2074).

This section presents background and introductory information on the formulation of this DMMP/EIS, including the purpose and

need, authorities for this study, and the Corps’ operation of the lower Snake River and McNary reservoirs, historic maintenance and

dredging activities, and related activities.

1.1 Study Authority

The Corps’ Dredged Material Management Study (DMMS) was initiated under the guidance provided in Engineer Circular (EC)

1165-2-200, Dredged Material Management Plans, which directs the development of DMMP's for Federal navigation projects, groups

of inter-related harbor projects, and systems of inland waterway projects. It is Corps policy to dispose of dredged material

associated with the construction or maintenance dredging of navigation projects in a manner that is the least costly, is consistent

with sound engineering practice, and that meets Federal environmental standards. Guidance for developing DMMPs is now

incorporated in Engineer Regulation (ER) 1105-2-100, Planning Guidance Notebook. The ER 1105-2-100 also provides the

requirements, as well as principles and guidelines, for conducting planning studies within the Corps’ Civil Works program and

ensuring environmental compliance through the planning process. Section 3-2 of ER 1105-2-100 provides specific guidance on the

maintenance of navigation projects and the preparation of dredged material management plans. A least-cost alternative, which is

compliant with environmental laws, forms the "base plan" against which other plan alternatives can be compared. Through the

DMMP planning process, the Corps has considered a range of management strategies, including approaches to reduce the need

for dredging and to beneficially use dredged materials, and has incorporated these strategies into its alternatives development and

evaluation process.

On May 4, 1995, the Corps Director of Civil Works provided guidance to the Commander, North Pacific Division, by memorandum

entitled “Lower Granite Lock and Dam, Washington, Sedimentation Studies Related to the Level of Protection Provided to the City of

Lewiston, Idaho.” This memorandum discussed a study to evaluate restoring the performance of project levees constructed to

protect Lewiston, Idaho, from inundation caused by the Lower Granite project. It states, “The study should evaluate a range of

alternative risk management plans, including modifications in the operation of the project and increased dredging.” In compliance

with this memorandum, consideration of reestablishing the flow conveyance capacity at Lewiston, Idaho, is included in the DMMS.

1.2 PURPOSE AND NEED

The purpose of this DMMP/EIS is threefold:

To develop and evaluate alternative programs to maintain the authorized navigation channel and certain publicly owned

facilities in the lower Snake River and McNary reservoirs for the next 20 years;

1.

To develop and evaluate alternative measures to maintain the flow conveyance of the Lower Granite reservoir for the remaining

economic life of the project (through 2074); and

2.

To develop and evaluate alternative programs of managing dredged material removed from these five reservoirs in a

cost-effective, environmentally acceptable, and, wherever possible, beneficial manner.

3.

The Corps is authorized by Congress to maintain a navigation system on the lower Snake and Columbia Rivers and to manage the

lock and dam/navigation projects (generally referred to as "projects" or "reservoirs" in this document) on the lower Snake River from

Lewiston, Idaho, to the McNary project at Umatilla, Oregon, on the Columbia River (which includes the confluence of the Columbia

and Snake Rivers). The Corps also maintains publicly owned recreational areas (such as marinas and swimming beaches), irrigation

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intake facilities for wildlife Habitat Management Units (HMUs) and recreation sites, and port access channels within the lower Snake

River and McNary reservoirs. Historically, the Corps has dredged accumulated sediments from the navigation channel and the other

facilities noted above on these reservoirs in order to maintain their operational capacities. Maintenance dredging actions are in

response to a variety of conditions including, but not limited to: emergency situations which would result in an unacceptable hazard

to navigation; programmed periodic dredge maintenance of known persistent shoal areas which impede navigation; and removal of

sediment that presents a hydraulic flow impediment.

In addition, sediment accumulation in the upstream reach of Lower Granite reservoir at the confluence of the Clearwater and Snake

Rivers has reduced the flow conveyance capacity of the river channel. If allowed to continue, this sedimentation would reduce the

flow capacity to a point that the Standard Project Flood [(SPF) an estimated or hypothetical flood that might be expected from the

most severe combination of weather and flow conditions that are considered reasonably characteristic of the geographical area]

would be expected to overtop the levees in Lewiston, Idaho, long before the end of the economic life of the project is reached in

2074 (Corps, 1993). To date, dredging has been the method of choice for the removal of this sediment and restoration of the flow

capacity.

The Corps policy stated in EC 1165-2-200 relates to development of a DMMP to address the dredged material management

requirements of the navigation projects within its jurisdiction. This policy encourages the development of a range of feasible

management alternatives that are cost effective and environmentally acceptable, and to seek to optimize beneficial uses of dredged

materials that may be generated. In preparing the DMMP, the Corps will assess opportunities to minimize dredging requirements

and maximize beneficial uses of dredged materials.

The Corps, Walla Walla District, is preparing this DMMP/EIS to address the maintenance of the authorized navigation channel and

specific public facilities for 20 years after the ROD is signed. This DMMP/EIS presents and analyzes management alternatives and

addresses management of dredged materials that are likely to result from these activities.

In addition, since dredging for flow capacity represents a significant quantity of historically dredged material volumes, this

DMMP/EIS evaluates future maintenance of flow conveyance through the remaining economic life of Lower Granite. Various

methods to maintain flow conveyance in Lower Granite are considered, including dredging and raising the existing levees in

Lewiston as a means of reducing dredged material volumes.

The development of the DMMP/EIS is consistent with the requirements of EC 1165-2-200 and has been integrated with the

requirements of the National Environmental Policy Act (NEPA).

1.3 DESCRIPTION OF THE STUDY AREA

Navigation on the Columbia and Snake Rivers has historically provided an important route of access into and from the interior

Columbia and Snake River basins (plate 1). As a part of its Congressional mandate, the Corps continues to maintain, enhance, and

operate the navigational improvements on the Columbia and Snake Rivers waterway. The Columbia and Snake Rivers projects

include channels, locks, and dams providing access to the ports, moorage, and recreational areas along the rivers.

The Corps typically maintains authorized channels on an as-needed basis by dredging to maintain the authorized channel depth.

Maintenance dredging of access channels to port and moorages occurs infrequently, on an as-needed basis. The Corps also

periodically conducts maintenance dredging around public recreation areas, such as swimming beaches, boat basins, and irrigation

intakes for wildlife HMUs and recreation sites managed by the Corps.

The Columbia and Snake Rivers navigation project begins at the mouth of the Columbia River near Astoria, Oregon, and extends to

Lewiston, Idaho, on the Snake River, a distance of approximately 460 miles [740.3 kilometers (km)]. A 40-foot- [12.2-meter (m)-]

deep, 600-foot-(182.9-m-) wide ship channel is authorized from the Columbia River Bar to Vancouver, Washington, and a 27-foot-

(8.2-m-) deep, 300-foot- (91.4-m-) wide ship channel is authorized from Vancouver to The Dalles Lock and Dam (The Dalles) on the

Columbia River. The 27-foot- (8.2-m-) deep channel is typically only maintained to a 17-foot (5.2-m) depth, reflecting the needs of

vessels using this reach. A 14-foot- (4.3-m-) deep, 250-foot- (76.2-m-) wide channel is maintained from The Dalles through McNary

on the Columbia River and through the four lower Snake River projects to Lewiston, Idaho.

Sill depths at the navigation locks limit the passage of vessels, commercial or recreational, on the Columbia and Snake Rivers. At

most of the projects, upstream sills are 15 feet (4.6 m) below the Minimum Operational Pool (MOP). The MOP provides the

clearance needed for a barge drafting between 13 and 14 feet (4 and 4.3 m), the typical draft of loaded barges operating in the

Columbia and Snake River fleet.

This document covers five locks and dams for the upper portion of the Columbia and Snake Rivers navigation project: McNary, Ice

Harbor Lock and Dam (Ice Harbor), Lower Monumental Lock and Dam (Lower Monumental), Little Goose Lock and Dam (Little

Goose), and Lower Granite. Each of these projects is authorized to provide navigation facilities including locks with dimensions of 86

feet (26.2 m) in width and over 665 feet (202.7 m) in length to allow passage of a tug with a four-barge tow commonly used in river

navigation. McNary lock provides a lift of approximately 75 feet (22.9 m), while each of the four Snake River locks and dams provide

between 98- and 100-foot (29.9- and 30.5-m) lifts, raising navigation from elevation 265 feet mean sea level (msl) below McNary to

elevation 738 feet msl in the Lower Granite reservoir. This portion of the waterway extends approximately 179 miles (288.1 km) from

McNary to Lewiston, Idaho. The initial McNary project, including construction of the locks, was completed in 1954 and provided

slackwater navigation to the Tri-Cities, Washington, area.

Ice Harbor, which began operation in December 1961, is approximately 8 miles (12.9 km) east of Pasco, Washington, and was the

first dam constructed on the Snake River in Washington. Three more dams were built on the Snake River in Washington over the

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next 13 years: Lower Monumental (1969), Little Goose (1970), and Lower Granite (1975). Construction of these dams has created a

series of slackwater reservoirs on the Snake River, adding an additional 140 miles (225.3 km) to the Columbia and Snake Rivers

shallow draft inland navigation system. This navigation system has resulted in a significant shift in the economy of eastern

Washington as new inland ports have become established to handle the needs of barge shippers. Wheat, barley, wood chips, and

other wood products are the primary commerce downbound from this region, with petroleum and fertilizer the principal commerce

upbound. These shipments depend on the availability of a navigation system that provides a 14-foot (4.3 m) draft channel for barge

tows.

1.4 EXISTING FEDERAL PROJECT AUTHORITY

The portion of the Columbia and Snake Rivers navigation system addressed in this DMMP/EIS was authorized by Section 2 of the

River and Harbor Act of 1945 (Public Law 79-14, 79th Congress, 1st Session) and approved March 2, 1945, in accordance with

House Document 704, 75th Congress, 3rd Session. The projects include:

McNary Lock and Dam - Lake Wallula, Columbia and Snake Rivers, Oregon and Washington.

Ice Harbor Lock and Dam - Lake Sacajawea, Snake River, Washington.

Lower Monumental Lock and Dam - Lake Herbert G. West, Snake River, Washington.

Little Goose Lock and Dam - Lake Bryan, Snake River, Washington.

Lower Granite Lock and Dam - Lower Granite Lake, Snake River, Washington.

Each of these projects is authorized to provide for slackwater navigation, irrigation, hydroelectric power generation, recreation, and

fish and wildlife.

Public Law 87-874, Title II - Flood Control Act of 1962, October 23, 1962, states:

"COLUMBIA RIVER BASIN

The projects and plans for the Columbia River Basin, including the Willamette River Basin, authorized by the Flood

Control Act of June 28, 1938, and subsequent Acts of Congress, including the Flood Control Acts of May 17, 1950,

September 3, 1954, July 3, 1958, and July 14, 1960, are hereby modified to include the projects listed below for flood

control and other purposes in the Columbia River Basin (including the Willamette River Basin) substantially in

accordance with the recommendations of the Chief of Engineers in House Document Numbered 403, Eighty-seventh

Congress: Provided, That the depth and width of the authorized channel in the Columbia-Snake River barge navigation

project shall be established as fourteen feet and two hundred and fifty feet, respectively, at minimum regulated flow."

Public Law 102-580, Water Resources Development Act of 1992, Section 109, authorizes the Secretary of the Army to maintain

navigation access to, and berthing areas at, all currently operating public and private commercial dock facilities associated with or

having access to the Federal navigation project on the Columbia, Snake, and Clearwater Rivers from Bonneville Lock and Dam

(Bonneville) to, and including, Lewiston, Idaho, at a depth commensurate with the Federal navigation project. A one-time

appropriation, to carry out the provisions of this section, was made in fiscal year 1992. Future Federal maintenance of non-Federal

commercial channels authorized under this Act would require special appropriation legislation. The Corps is also authorized to

maintain associated publicly owned recreation areas and wildlife HMUs.

Lower Granite includes levees as appurtenant facilities of the authorized project to allow normal operating water surface elevations

of 733 to 738 feet msl in the Lewiston, Idaho, and Clarkston, Washington, areas. These backwater levees constructed around

Lewiston were designed to protect the city from inundation during the occurrence of the SPF and to maintain flow conveyance

capacity.

1.5 HISTORY AND BACKGROUND

Several locations along the Snake and Columbia Rivers have required periodic dredging to maintain the authorized channel depth,

and several ports have experienced frequent sediment-related problems in accessing their loading or docking facilities. In the 8-year

period from 1991 through 1998, there were navigation-related dredging activities in all of the reservoirs in the study reach. Some of

these dredging projects were directed toward cleaning out berthing areas, turning basins, and access channels for individual ports,

and some were directed toward restoring the authorized depth in the main navigation channel. The Corps has also performed

periodic maintenance dredging of relatively small amounts of sediments around public recreation areas and irrigation intakes for

wildlife management areas. Table 1-1 presents the history of dredging of this system.

Table 1-1

History of Dredging in Lower Snake River and McNary Reservoirs

Dredging Location Year Purpose

Amount

Dredged

(cubic yards)

(m3) Disposal

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Excavation of Navigation Channel Ice Harbor Lock and

Dam, Part I and II, Channel Construction 1961 Navigation 3,309,500(2 530 294) Unavailable

Navigation Channel, Ice Harbor Lock and Dam Part III,

Channel Construction 1962 Navigation 120,000(91 746.6) Unavailable

Downstream Navigation Channel, Ice Harbor Lock and

Dam 1972 Navigation 80,000(61 164.4) Unavailable

Downstream Approach, Navigation Channel,

Lower Monumental Lock and Dam 1972 Navigation 25,000(19 113.9) Unavailable

Navigation Channel Downstream of

Ice Harbor Lock and Dam 1973 Navigation 185,000(141 442.6) Unavailable

Downstream Approach Channel Construction,

Lower Monumental Lock 1977 Navigation 10,000(7 645.5) Unavailable

Downstream Approach Channel Construction,

Ice Harbor Lock 1978 Navigation 110,000(84 101) Unavailable

Downstream Approach Channel Construction,

Ice Harbor Lock 1978/81/82 Navigation 816,814(624 499.1) Unavailable

Recreation Areas (Corps) 1975-present Recreation 20,000

(15 291.1) Upland Sites

Port of Lewiston - Lower Granite Reservoir (Corps) 1982

Navigation/Maintain

Flow Conveyance

Capacity

256,175

(195 859.8)

Port of Clarkston - Lower Granite Reservoir (Port) 1982 Navigation 5,000

(3 822.8) Upland Site

Downstream Approach Channel Construction,

Ice Harbor Lock 1985 Navigation 98,826(75 557.9) In-Water

Confluence of Clearwater and Snake Rivers (Corps) 1985

Maintain Flow

Conveyance

Capacity

771,002

(589 473.3) Wilma HMU

Port of Lewiston - Lower Granite Reservoir (Corps) 1986

Navigation/Maintain

Flow Conveyance

Capacity

378,000

(289 001.7) Upland Sites

Confluence of Clearwater and Snake Rivers (Corps) 1988

Maintain Flow

Conveyance

Capacity

915,970

(700 309.3) In-Water

Confluence of Clearwater and Snake Rivers (Corps) 1989

Maintain Flow

Conveyance

Capacity

993,445

(759 543.2) In-Water

Schultz Bar - Little Goose Reservoir (Corps) 1990 Navigation 27,335

(20 899.1)

Not

Applicable

Confluence of Clearwater and Snake Rivers (Corps 1992

Maintain Flow

Conveyance

Capacity

520,695

(398 099.9) In-Water

Ports of Lewiston (Lower Granite Reservoir), Almota, and

Walla Walla 1991/92 Navigation 90,741(69 376.5) Unavailable

Boise Cascade - McNary Reservoir near Wallula, WA 1992 Navigation 120,742

(92 313.9) In-Water

Port of Kennewick - McNary Reservoir 1993 Navigation 6,130

(4 686.7)

Not

Applicable

Schultz Bar - Little Goose Reservoir (Corps) 1995 Navigation 14,100

(10 780.2) In-Water

Confluence of Clearwater and Snake Rivers (Corps) 1996/97 Navigation 68,701

(52 525.7) In-Water

Confluence of Clearwater and Snake Rivers (Corps) 1997/98 Navigation 215,205

(164 536) In-Water

Greenbelt Boat Basin, Clarkston - Lower Granite Reservoir 1997/98 Navigation 5,601

(4 282.3) In-Water

Port of Lewiston - Lower Granite Reservoir (Port) 1997/98 Navigation 3,687

(2 818.9) In-Water

Port of Clarkston - Lower Granite Reservoir (Port) 1997/98 Navigation 12,154

(9 292.4) In-Water

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Lower Granite Navigation Lock Approach 1997/98 Navigation 2,805

(2 144.6) In-Water

Lower Monumental Navigation Lock Approach 1998/99 Navigation 5,483

(4 192.1) In-Water

Source: U.S. Fish and Wildlife Service (USFWS), August 1998/Corps, July 19, 1995, and September 2, 1999.

Several major tributaries enter the Snake or Columbia Rivers within the study area, and most are heavy sediment contributors in

high runoff years. Projections of sediment inflow and deposition indicate more sediment buildup at the tributary mouths that may,

over time, affect the navigation channel, requiring more frequent dredging at these locations.

Lower Granite, the most upstream of the four lower Snake River dams, is the final link in the inland waterway system that provides

slackwater navigation to the cities of Lewiston, Idaho, and Clarkston, Washington. Because this reservoir is the most upstream in the

lower Snake River system, it is the predominant sediment collection area for a large sediment-contributing drainage area that

includes the Salmon, Grande Ronde, and Imnaha Rivers; the main stem of the Clearwater River; and the local drainage of the

Snake River between the Hells Canyon complex and Lower Granite. The upper reach of the Lower Granite reservoir serves as a

sediment trap for most of the material carried in suspension in the free-flowing reaches of the contributing rivers. The quantity of

sediment that collects in the Lower Granite reservoir exceeds the quantities observed in each of the other lower Snake River

reservoirs and in the McNary reservoir.

The deposition of sediments at the upstream end of the Lower Granite reservoir impacts backwater levee systems constructed at the

cities of Lewiston and Clarkston. The Lower Granite project included a backwater levee system in lieu of relocating the business

district of Lewiston. This levee system was not designed primarily to provide flood control to Lewiston; rather, it was designed and

constructed to be an upstream extension of the dam. This project element was designed to allow the Lower Granite reservoir to

pass an SPF event while protecting Lewiston from inundation.

The levee system was designed to provide a minimum freeboard of 5 feet (1.5 m) during the SPF event of 420,000 cubic feet per

second (cfs) [11 893.1 cubic meters per second (m3/s)] on the Snake River below the confluence of the Clearwater River. Since the

reservoir was filled in 1975, sediment deposition has reduced the channel capacity, causing the computed water surface elevations

associated with a particular discharge to rise. The sedimentation deposition has restricted the channel so that the SPF event cannot

pass without seriously encroaching into the levee freeboard. Subsequent studies conducted by the Corps indicate that overtopping

of the levees could occur in the future.

Sediment accumulation in Lower Granite reservoir continues to reduce the level of protection provided by the levees. Less than 3

feet (0.9 m) of the originally designed 5 feet (1.5 m) of levee freeboard remain for the SPF. Approximately 2.2 million tons (2.0 metric

tons) or 3.2 million cy (2.4 million m3) of sediment collects in the reservoir annually. During the first 12 years of operation, the

average annual reduction in levee freeboard was 3 inches [7.6 centimeters (cm)] per year. Projections indicate that, without

corrective action, the SPF could overtop the existing levees.

A dredging and experimental in-water disposal test program was conducted over the period between 1985 and 1993 to determine

acceptable solutions to the sedimentation problems in Lower Granite reservoir. Disposal of dredged material was a problem due to

limited availability of upland disposal sites combined with the need to dredge for navigation and flow conveyance. Dredged material

from the upper reservoir was considered to be potentially beneficial in creating shallow water habitat. Shallow water habitat provides

foraging opportunities and short-term rearing for downstream migrating salmonid fishes and spawning and rearing habitat for

resident game fishes. This experimental in-water disposal test was implemented in 1985 with an exhaustive monitoring program to

assess the value of using dredged material for fish habitat enhancement. As a part of this test, an underwater bench and island

(Centennial Island) were constructed at mid-depth (20 to 60 feet) (6.1 to 18.3 m) with additional disposal at a deep-water (greater

than 60 feet) (greater than 18.3 m) site between river mile (RM) 120 and Lower Granite. Fish assemblages were sampled before the

test began in 1985 and after construction of the dredged disposal island in 1993 to assess local changes in community structure.

The results of this test suggest that construction of shallow water habitat using dredged material has a potential for increasing

habitat complexity in Lower Granite reservoir.

1.6 RELATED ACTION PROGRAMS

In February 2002, the Corps issued the Final Environmental Impact Statement (FEIS) for the Lower Snake River Juvenile Salmon

Migration Feasibility Study (Feasibility Study), which analyzed measures that may increase the survival of juvenile anadromous fish

through the lower Snake River project [which includes the four lowermost dams operated by the Corps on the Snake River (Ice

Harbor, Lower Monumental, Little Goose, and Lower Granite)] and assist in the recovery of listed salmon and steelhead stocks.

Several key aspects of the Feasibility Study and this DMMP/EIS are interrelated. The history of the development of the Feasibility

Study and its relationship to this DMMP/EIS are discussed below. The Final Feasibility Study EIS and supporting documentation are

incorporated by reference in the DMMP process.

On November 20, 1991, the National Marine Fisheries Service (NMFS) declared the Snake River sockeye salmon as Endangered

effective December 20, 1991 (56 FR 58619). Snake River spring/summer chinook and Snake River fall chinook salmon were listed

as Threatened on April 22, 1992 (57 FR 14653). Critical habitat was designated for Snake River sockeye, spring/summer chinook,

and fall chinook salmon on December 28, 1993 (58 FR 68543). Snake River basin steelhead were formally listed as Threatened on

August 18, 1997 (62 FR 43937).

On March 2, 1995, NMFS issued a Biological Opinion for the Reinitiation of Consultation on 1994-1998 Operation of the Federal

Columbia River Power System and Juvenile Transportation Program in 1995 and Future Years. The 1995 Biological Opinion

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established measures necessary for the survival and recovery of Snake River salmon listed under the Endangered Species Act

(ESA).

The Corps’ primary responsibility in implementing the measures prescribed in the 1995 Biological Opinion is to study those

measures that are associated with dams and reservoirs and that influence fish migration through the hydro system. Thus, the

purpose of the Feasibility Study is to evaluate and screen alternative measures that may increase the survival of juvenile

anadromous fish through the lower Snake River project and, therefore, assist in the recovery of listed salmon and steelhead stocks.

The Feasibility Study considered four alternatives; three of the alternatives would keep the dams in place, while one alternative

includes breaching of the earthen portion of the four dams. Breaching the dams would allow the lower Snake River to return to a

more free-flowing condition, while eliminating hydropower production and the ability to use river navigation for the shipments of

goods between the Lewiston-Clarkston area and the Tri-Cities area. The Corps considered public input on the Feasibility Study

received through extensive outreach and public comments on the Draft FR/EIS. The recommended plan documented in the

Feasibility Study Final EIS is "major system improvements (adaptive migration)," and features structural and operational measures

that are considered to be technically feasible, and which the Corps has the capability to design, construct, and operate.

The Feasibility Study process and its ultimate recommendations may affect the management of the lower Snake River and McNary

reservoirs. This DMMP/EIS addresses long-term (20 years) management of dredged material by providing a programmatic

"framework" or "road map." As such, this DMMP/EIS incorporates a number of assumptions about the future operations of the lower

Snake River projects, including the assumption of continued navigation on the lower Snake River (i.e., that the four lower Snake

River dams would not be breached). However, by incorporating this assumption, the DMMP/EIS does not pre-determine the

outcome of the Feasibility Study process, nor whether the lower Snake River dams would be kept in place or breached. In fact, the

DMMP is based upon an adaptive management approach that would allow the Corps a degree of flexibility to accommodate certain

regulatory, policy, or environmental changes over the 20-year timeframe of the plan.

As a programmatic plan, this DMMP/EIS accounts for the fact that the Feasibility Study process may determine that the lower Snake

River dams are to stay in place, be modified in place, or breached. If the dams stay in place, this DMMP/EIS would continue to set

the management objectives for the lower Snake River and McNary reservoirs. On the other hand, if the Feasibility Study process

concludes that the dams should be modified or removed, this DMMP/EIS would be necessary for the interim management of the

lower Snake River projects. Also, if the lower Snake River dams are breached, this DMMP/EIS would need to be revised to address

the changed navigation and sedimentation conditions in McNary reservoir. On the other hand, data from the NMFS 2000 BiOp

check-in points in 2003, 2005, and 2008 and other new information could result in a decision to modify or breach these four dams,

this DMMP would still be necessary for interim management and to address conditions in the McNary Reservoir.

After publication of the Draft FR/EIS, NMFS issued a Biological Opinion (December 21, 2000) to the Bonneville Power Administration

(BPA), the Corps, and the Bureau of Reclamation. In this Biological Opinion, NMFS calls for various Habitat Actions. One of the

stated goals of these Habitat Actions as they apply to main stem habitat is to "improve main stem habitat on an experimental basis

and evaluate the results." The specific Action Item, Action #155, states that, "BPA, working with the BOR, Corps, the Environmental

Protection Agency (EPA), and the U.S. Geological Survey, shall develop a program to: (1) identify mainstem habitat sampling

reaches, survey conditions, describe cause-and-effect relationships, and identify research needs; (2) develop improvement plans for

all mainstem reaches; and (3) initiate improvements in three mainstem reaches. Results shall be reported annually." As one means

of achieving this, the Biological Opinion states that, "BPA, working with the Corps, will take immediate steps to begin to address

these uncertainties by . . . improving mainstem reaches in ways that mimic the range and diversity of the historic habitat conditions

as much as possible, and monitoring and evaluating the results." The beneficial use of dredged materials, including development of

mid-depth and shallow water rearing habitat as proposed in this DMMP/EIS would contribute toward these actions proposed by

NMFS.

Whatever the outcome of the Feasibility Study process, this DMMP/EIS would provide management guidance over the short term.

The adaptive management approach of the DMMP’s recommended plan would also allow it to be modified or amended to account

for changes that may occur to the system over the next 20 years.

1.7 ECONOMIC JUSTIFICATION

The recommended DMMP is economically justified by confirming that transportation savings over the next 20 years resulting from

the dredging program exceed the cost of maintenance of the navigation project. Benefits in transportation costs to barge shippers of

commodities on the lower Snake River system were compared with the cost of providing the authorized channel depths and

maintaining the navigation features of the system.

Justification for the restoration of flow conveyance capacity in the Lower Granite reservoir is determined by comparing costs of

alternatives to increase conveyance with the expected reduction in flood damages based on the results of a risk-based flood

damage assessment. Economic feasibility of an acceptable alternative to restore flow conveyance capacity is based on maximization

of net benefits computed over the remaining economic life of the project to year 2074 at a 6.875 percent interest rate.

1.7.1 Navigation

Barge navigation on the lower Snake River system accommodates the downbound transport of wheat, barley, wood chips, other

wood products, and miscellaneous agricultural products and the upbound transport of petroleum, fertilizer, and other consumer

goods. The authorized navigation project on the lower Snake River provides 14 feet (4.3 m) of depth at normal operating pool levels.

Impacts to shallow draft commercial navigation from sedimentation and shallowing of the authorized channels above McNary are

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estimated from information presented in the Columbia River System Operation Review, Final Environmental Impact Statement,

dated November 1995, Appendix O, Economic and Social Impact, page 453. Transportation costs for commerce moving to and from

the Snake River projects on the Columbia and Snake Rivers system were estimated at $414.43 million in 1992 under present

authorized channel depths. The cost of transporting the same commerce over alternative landforms of transportation was estimated

to be $458.33 million. The difference of $43.90 million (that is, $458.33 minus $414.43) can be considered the annual benefits

attributable to barge navigation on the Snake River system. A similar evaluation was presented in the February 2002 FR/EIS. The

FR/EIS estimated the increased average annual transportation costs resulting from the elimination of barge transportation at

$43.191 million in 2002 dollars [Snake River Juvenile Salmon Migration Feasibility Report/EIS, appendix I, February 2002, Table

ES-15]. Wheat and barley shipments represented more than 60 percent of the tonnage and more than 90 percent of the

transportation savings. Barge commerce above McNary is expected to continue to grow over the next 20 years and transportation

benefits are expected to grow similarly. Forecasts of barge transportation in the 20-year period of this DMMP/EIS show tonnage to

increase to between 7.9 and 10 million tons (7.1 and 9.0 metric tons) by the year 2020 from nearly 7 million tons (6.3 metric tons) in

the mid-1990's.

Average annual costs to provide the dredging maintenance of channels and operate the navigation features in the five dams and

reservoirs were estimated and compared with estimates of transportation savings described above to determine the economic

justification of continued maintenance of the system. Channel maintenance average annual costs are estimated at $560,000

computed over the 20-year period at a 6.875 percent interest rate. This cost estimate is based on maintaining the authorized

navigation channel dimensions over the next 20 years using clamshell dredging, bottom-dump barges, and in-water disposal of the

dredged material. Use of hydraulic equipment was not considered acceptable because of the anticipated adverse impact on

endangered fish resources. Disposal at upland sites instead of in-water sites was considered, but found to be more costly and

provide less environmental benefit than in-water disposal. In addition to channel maintenance costs, annual costs include $2.14

million (expended in fiscal year 1998) for the operation and maintenance of navigation locks at each of the five reservoir projects.

Comparing the annual $43.191 million in transport savings estimated for just the Snake River portion with the combined channel

average annual maintenance and 1998 navigation lock operation and maintenance costs of $2.70 million ($0.56 + $2.14) results in a

benefit-to-cost ratio of 16.0 to 1.0. This portion of the Columbia and Snake River navigation system provides a very strong economic

justification for the continued maintenance of this system. The study described in section 1.6 considers various levels of navigation

clearances and evaluates the resultant effects. All alternatives described in this DMMP/EIS provide 14-foot (4.3-m) navigation

clearances over the Federal navigation system. Appendix A, Hydrologic Analysis, contains a summary description of the dredging

operations and appendix B, Cost Estimates, presents the cost estimate of each dredging and disposal alternative.

Consideration can also be given to reduced maintenance that would result in a change in depth to the authorized Federal channel

causing transportation companies to light load their equipment to accommodate a shallower channel. Navigation benefits and

dredging costs can be compared on an incremental basis for different channel conditions to determine if channel maintenance is

more cost effective than light-loading barges. Commodity transportation and barge cost data prepared for the Lower Snake River

Feasibility Study were used to determine the feasibility of the maintenance dredging proposed and evaluated in the DMMP/EIS. For

this analysis two shallower Federal navigation channels, with controlling depths of 13 feet and 12 feet, were assumed to result from

termination of maintenance dredging. Grain shipments, representing 78.8% of the commerce on the Snake River for the period of

1987 to 1996, were selected to represent the impacted commerce. Grain barge costs for shipments from the various ports on the

Snake River system were developed to reflect light-loading to accommodate the shallower channels. Reduced cargo capacity of the

standard 3,600-ton grain barge (274 feet long, 42 feet wide, and 13.5 feet draft) with drafts of 12.5 feet and 11.5 feet were

determined to be 3,270 tons and 2,950 tons, respectively. The impact of this reduced capacity would be to raise per ton barge costs

by 10% and 22%, respectively. The resultant increase in transportation costs for moving the forecast grain shipments from the

Snake River in the 20-year period was compared to the avoided annual cost of maintenance dredging. The result of this analysis,

based on 1999 costs, indicated that dredging costs were equal to the estimated increase in barge costs when the channel capacity

was reduced by only one foot. However, where channel depths were reduced by two feet, the cost of dredging was about half of the

increased cost to barge transportation. In essence, shoaling that reduces the channel depth by one foot represents the "break

even" point where maintenance dredging is feasible and cost effective when only grain shipments are considered. While this study

was not an exhaustive analysis of the feasibility of reduced channel maintenance dredging, it indicates that dredging was more cost

effective than light loading the present barge equipment. If all the waterborne commerce on the Snake River is considered the

maintenance dredging of the channel would be clearly more feasible and cost affective than light loading barges.

1.7.2 Conveyance Capacity

Existing levees, protecting the city of Lewiston, Idaho, from reservoir backwaters, were built as a part of the construction of Lower

Granite. Sediment deposition in the Lower Granite reservoir threatens to reduce the channel capacity and cause flows to overtop

levees and flood developed areas. Correction of this condition has been the subject of memoranda between the Walla Walla District

and Corps Headquarters. In a memorandum dated May 4, 1995, the Director of Civil Works, Corps of Engineers, stated that a study

was needed to evaluate restoring the performance of the project levees constructed to protect Lewiston, Idaho. It further stated,

"The study should evaluate a range of alternative risk management plans, including modifications in operation of the project and

increased dredging." Flow conveyance could be provided by dredging and, therefore, it was considered appropriate to formulate the

plan as part of this DMMP/EIS. This DMMP/EIS includes the results of the risked-based analysis conducted to determine the

appropriate means of restoring the flow conveyance capacity in the confluence area of Lower Granite reservoir.

Risk-based analysis is an approach to evaluation and decision making that explicitly incorporates considerations of risk and

uncertainty. This approach combines the underlying risk and uncertainty information so that the engineering and economic

performance of a project can be expressed in terms of probability distributions. The objective is to identify and recommend a flood

damage reduction alternative that reasonably maximizes expected net benefits (expected annual damages reduced minus the

average annual cost of the alternative). No longer is protection against the SPF with 5 feet (1.5 m) of freeboard the criteria for the

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levees protecting the Lewiston-Clarkston area. As of 1977, the base year for the analysis, the project provided protection against a

flow condition having a recurrence interval of 500 years. Sedimentation in the confluence area would reduce the protection by the

year 2021 to a 167-year recurrence interval and by 2074 to a 83 year recurrence interval without any upgrade to the levee system.

A number of measures were considered to restore the flow conveyance capacity including making operational changes, dredging

additional material to provide adequate channel capacity below elevation 738 feet msl, and raising the height of the existing levees

to allow for water surface increases. Operational changes were found not to be an effective method of restoring flow conveyance

capacity, as discussed in section 2, and this study concentrated on dredging and levee raise alternatives. All flow restoration options

were considered to provide the flow conveyance needed after the navigation maintenance dredging program (considered the

baseline in this study) had been implemented. Various dredging options including removing 300,000 cy (229 366.5 m3) per year, 1

million cy (764 555 m3) per year, and 2 million cy (1 529 110 m3) per year were considered. Levee modifications providing nominal

raises of 3 feet (0.9 m), 4 feet (1.2 m), 8 feet (2.4 m), and 12 feet (3.7 m) were also considered. These levee raise alternatives are

identified nominally by their largest levee height increase expressed to the nearest foot (meter). This identification is nominal since

the actual levee raise varies along the length of the existing levee. Where necessary to protect against design water surface profiles

for nominal levee raises exceeding 3 feet (0.9 m), the levee footprint was extended upstream as described in appendix E, Lewiston

Levee Modification Extension Analysis. Cost estimates were developed for each of the dredging and levee raise alternatives and

converted to annual costs based on 6.875 percent interest over the remaining life of the project to year 2074. Only those dredging

costs above the base navigation maintenance plan were accepted as costs relating to flow conveyance capacity. Flood damage

reduction estimates were obtained using the Corps Hydrologic Engineering Center Flood Damage Assessment (HEC-FDA) model.

This model is consistent with the Corps’ Engineering Manual 1110-2-1619, Risk-Based Analysis for Flood Damage Reduction

Studies. Results from the risk-based model were converted to average annual damages reduced for each alternative and compared

to their annual cost.

The risk-based flood damage assessment and economic analysis, presented in appendix C, Economic Analysis, indicates that a

nominal levee raise of 3 feet (0.9 m) provides maximum net flood damage reduction benefits. Information presented on page 48 of

appendix C was converted to average annual costs and benefits. This economic analysis shows that a nominal 3-foot (0.9-m) levee

raise would have annual costs of $152,000 and annual flood damage reduction benefits of $689,000 with a net benefit of $537,000.

A levee alternative providing a nominal 4-foot (1.2-m) raise would have average annual costs of $938,000 and annual flood damage

reduction benefits of $793,000, producing net benefits of -$145,000. A dredging alternative providing somewhat higher flood

damage reduction benefits to the 3-foot (0.9 m) levee raise would have annual costs of $1,233,000, approximately eight times

greater than the levee alternative. The value of average annual flood damages that could occur without a modification was

computed to be $941,000 over the life of the project discounted by 6.875 percent. None of the flow conveyance alternatives with

annual costs that exceeded $941,000 could be considered economically feasible and, therefore, were not considered further.

Accordingly, dredging alternatives to provide flow conveyance with average annual costs ranging from $1,233,000 to $4,706,000 are

not considered feasible. Table 1-2 presents the results of these economic investigations. Appendix C and the remainder of this

DMMP/EIS provide the details of the economic studies, with the incremental analysis results and discussion of impacts and

mitigation requirements.

Table 1-2

Comparison of Alternatives

Alternative

Annual

Alternative

Costs1

Annual

Damages

Reduced2

Net

Annual

Benefits

No Action (No Change)

Maintenance Dredging $0.0 $0.0 $0.0

3-Foot (0.9-m) Levee Raise $152.0 $689.0 $537.0

4-Foot (1.2-m) Levee Raise $938.0 $793.0 -$145.0

8-Foot (2.4-m) Levee Raise $2,595.0 3 3

12-Foot (3.7-m) Levee Raise $4,259.0 3 3

300,000 CY (229 366.5 m3) Dredge $1,233.0 3 3

1 million CY (764 555 m3) Dredge $1,911.0 3 3

2 million CY (1 529 110 m3) Dredge $4,706.0 3 3

Notes:

1Costs presented in this table are in $1,000 computed as average annual values computed at 6.875% interest for the period 2001 to 2074 from table 10, Appendix C.

2Benefits presented are in $1,000 computed as average annual values computed at 6.875% interest for the period 2001 to 2074, based on values presented in table 11,

Appendix C.

3All of these alternatives have annual costs that exceed the total annual damages computed at 6.875% interest for the period 2001 to 2074 from values presented in Appendix

C.

1.8 LOCAL SEDIMENT MANAGEMENT GROUP

A Local Sediment Management Group (LSMG) has been formed, and has met on three occasions (July 2000, February 2001, and

December 2001), to provide input in the development of this DMMP/EIS, as well as coordination of the plan’s implementation (i.e.,

the dredging and dredged material management activities). This group has been formed consistent with the inter-agency National

Dredging Team’s guidance (EPA, 1998a). Roles within the LSMG will continue to develop in accordance with policies and

procedures currently evolving for the RDT, as referenced in the April 26, 2002 policy letter jointly signed by Brigadier General David

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A. Fastabend (Corps of Engineers Northwest Division Commander) and L. John Iani (EPA Region 10 Administrator).

The LSMG would assist in the development and adoption of appropriate method(s) for management of dredging and use and/or

disposal of dredged material from Federal navigation and maintenance projects and dredging activities regulated under Section 404

of the Clean Water Act. In the formulation of these management policies, the LSMG would be asked to consider key environmental

laws and regulations involved in this process; consider the responsibilities of other Federal, state, and local resource agencies; and

help develop a coordination process for dredging and beneficial use of dredged material. In addition the LSMG would assist the

Corps in evaluating dredging and dredged material management activities and options consistent with an adaptive management

approach.

The general objectives of the LSMG are:

Provide an interagency approach to dredged material management.

Promote consistency in dredging and sediment management activities.

Assist in development of monitoring plans and sediment sampling and testing framework.

Facilitate adaptive management and beneficial use of dredged materials.

Promote consideration of all environmental laws and regulations.

Consider necessary cultural resource protection.

Discuss and evaluate possible strategies to reduce sediments entering the lower Snake River system.

Involve other stakeholder groups and pursue consistency with their plans.

The Corps anticipates that the LSMG will convene regularly, either annually or semi-annually, depending on the Corps’ anticipated

dredged material management activities. The LSMG will consider all dredging and dredged material management activities for the

ensuing time period. Specifically, it is envisioned that the LSMG will consider proposed dredging, suggest ways of potentially

reducing dredging requirements, explore promising beneficial uses of dredged materials, and comment on proposals for in-water

habitat creation using dredged materials.

As situations develop which call for maintenance dredging, the LSMG would be informed. The situations expected to require

maintenance dredging could include, but would not be limited to:

Emergencies involving shoaled areas that pose a serious risk to navigation of commercial vessels as indicated by records of

groundings, complaints by shippers, and/or condition surveys of the navigation channel.

Programmed/periodic dredge maintenance activities based on well-established historical records of persistent shoaling in a

navigation channel that could pose a serious risk to navigation of commercial vessels.

Shoaled areas that pose a serious risk to navigation and moorage of recreational craft as indicated by comments of operators

of recreational boat facilities and/or condition surveys.

Sedimentation to irrigation intakes associated with Lower Snake River Habitat Management Units (HMU) which restricts the

ability to deliver irrigation water to the HMU.

Sedimentation to irrigation intakes associated with Corps-managed recreation areas.

Advanced maintenance of a commercial navigation channel or berth which historically requires dredging to remove shoals that

pose a serious risk to navigation, when an opportunity to meet a specific environmental restoration need for beach

nourishment exists and/or when the dredging can be combined with other maintenance dredging to lower the cost and

minimize the dredge related disturbance to transportation and local business activities.

Further, it is anticipated that the LSMG would provide a forum to address historic inconsistencies in dredging and disposal methods

and in-water work windows, and discuss ways of bringing consistency to dredging-related activities within the study area. The LSMG

would also serve as a forum for providing suggestions to the Corps on improving the implementation of the DMMP/EIS.

The following Federal and state agencies and tribes with responsibilities applicable to the DMMP/EIS have been asked to participate

in the LSMG to facilitate the accomplishment of the general objectives:

Bonneville Power Administration

Confederated Tribes and Bands of the Yakama Indian Nation

Confederated Tribes of the Colville Reservation

Confederated Tribes of the Umatilla Indian Reservation

Idaho Department of Fish and Game

Idaho Department of Water Resources

Idaho Division of Environmental Quality

Idaho State Historical Society (State Historic Preservation Officer)

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Oregon Department of Environmental Quality

Oregon Department of Fish and Wildlife

Oregon Division of State Lands

Oregon State Historic Preservation Office

Oregon Water Resources Department

National Marine Fisheries Service

Nez Perce Tribe

U.S. Army Corps of Engineers, Northwest Division

U.S. Army Corps of Engineers, Portland District

U.S. Army Corps of Engineers, Seattle District

U.S. Army Corps of Engineers, Walla Walla District

U.S. Department of Energy

U.S. Environmental Protection Agency, Region 10

U.S. Fish and Wildlife Service

Wanapum Band

Washington Department of Ecology

Washington Department of Fish and Wildlife

Washington Department of Natural Resources

Washington State Historic Preservation Officer

Additionally, public ports within the study area have been invited to participate in the LSMG. Other local entities with an interest in

management of the resources involved in dredging and disposal activities (e.g., counties, municipalities, environmental groups, and

transportation and industrial interests) would be asked to participate on a regular basis.

The LSMG has been identified as a forum for discussion of possible measures to reduce sedimentation in the lower Snake River

system and McNary reservoir. To facilitate these discussions, land management and conservation agencies such as the U.S. Forest

Service, the Natural Resources Conservation Service, and others that may have a role in sediment reduction strategies, will be

asked to participate in the LSMG.

1.9 LOCAL SPONSORS

Beneficial uses of the dredged material may be undertaken solely by the Corps, without non-Federal cost sharing, where it is

consistent with the authorized project purpose (such as woody riparian habitat or shallow water habitat development). The Corps’

project authorization requires maintenance of the navigation channel in the lower Snake River and in the Columbia River upstream

of McNary. Historically, the ports and other users located on the rivers that benefit from and rely on maintenance of navigation on

this inland waterway system have requested that the Corps provide dredging to maintain their facilities. The dredging of ports and

other non-Federal facilities is a reimbursable cost paid to the Federal Government.

Potential local sponsors for navigation maintenance activities on the lower Snake River and McNary reservoirs include the public

port authorities listed on the following page. In addition, there are numerous private port and dock facilities on the lower Snake and

Columbia Rivers within the study area. Periodic dredging of port facilities may be required. For example, in the 1997-1998

confluence dredging, the Corps dredging contractor removed 3,687 cy (2 818.9 m3) of material from the Port of Lewiston and 12,154

cy (9 292.4 m3) from the Port of Clarkston.

Public Port Authorities

- Port of Benton County

- Port of Clarkston

- Port of Garfield

- Port of Kennewick

- Port of Lewiston

- Port of Pasco

- Port of Umatilla

- Port of Walla Walla

- Port of Whitman County

Other potential local sponsors of dredged material management activities include agencies or individuals who are willing to share in

the cost of beneficial use of dredged material. Beneficial uses of dredged material to protect, create, or restore aquatic and wildlife

habitat are authorized under Section 204 of the Water Resources Development Act of 1992. Implementation of beneficial use

projects is conditioned on local sponsors agreeing to pay 25 percent of the cost of implementing the project and 100 percent of

maintenance costs. Similarly, use of dredged material for other purposes not related to ecological restoration (e.g., use as fill or

cover material) may be undertaken provided additional costs to Federal agencies are not incurred. Local sponsors who identify such

a beneficial use are responsible for financing all the costs associated with implementing and maintaining the use. The LSMG would

serve as a forum for identifying sponsors and planning beneficial uses of dredged materials.

Potential local sponsors for beneficial use of dredged material include:

Port of Whitman County to fill additional dredged material disposal cells at Port of Wilma.

Port of Whitman County as a raw material source for production of potting soil.

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State wildlife agencies and wildlife organizations for habitat creation by shoreline terracing and covering exposed riprap.

The U.S. Department of Energy for capping contaminated material in environmental restoration projects at the Hanford

Reservation.

Public landowners.

Potential beneficial uses of dredged material are discussed in detail in section 2.5.4.

Section 2

Alternatives

The Corps’ planning guidelines and NEPA require the consideration and analysis of a broad range of alternative approaches in the

development of this DMMP/EIS. Section 2 presents the process to formulate the plan alternatives that were considered by the Corps

in developing this DMMP/EIS (figure 2-1). This process includes:

The development of plan measures (or types of actions) that, of themselves, address one or more of the requirements of the

purpose and need discussed in section 1.2.

Screening the plan measures to determine their effectiveness and suitability to include in plan alternatives.

Formulating plan alternatives (or packages of one or more plan measures) that fully address the requirements of section 1.2,

Purpose and Need.

Those alternatives that reasonably and efficiently meet the Corps’ planning objectives are further evaluated and compared in

detail in sections 3 and 4. From these alternatives, a preferred alternative (or “recommended plan”) would be selected. In

addition, the "No Action (No Change)" alternative is presented and evaluated.

Figure 2-1. DMMP/EIS Plan Formulation Process

2.1 INITIAL OPTIONS

The Corps’ DMMS examined methods for maintaining the existing 14-foot (4.3-m) draft navigation channel and other related features

in the five reservoirs on the Columbia and lower Snake Rivers:

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Lake Wallula (McNary).

Lake Sacajawea (Ice Harbor).

Lake Herbert G. West (Lower Monumental).

Lake Bryan (Little Goose).

Lower Granite Lake (Lower Granite).

This DMMP and programmatic EIS are built on studies that have been ongoing since the mid-1980s and address management of

dredged material for the next 20 years.

In addition to addressing the navigation maintenance needs, this study examines methods to maintain flow conveyance capacity in

the upper reach of Lower Granite reservoir through the remainder of its economic life to year 2074 (Corps, 1993). Flow conveyance

capacity is achieved currently through dredging. The continued need for flow conveyance capacity maintenance was based on the

results of a risk-based flood damage assessment that considered the conditions with the 14-foot (4.3-m) navigation channel

maintained. Dredging alternatives that both maintain navigation and meet the feasible flow conveyance needs were developed and

compared to a full array of alternatives including levee raise alternatives. Levee raise alternatives were found to be a cost-effective

substitute for dredging to achieve flow conveyance. The objective was to select an alternative that maximized flow conveyance

capacity and net flood damage reduction benefits, based on engineering, environme ntal, and social criteria, and present it in this

DMMP/EIS.

In accordance with the requirements of the NEPA, a broad range of alternatives that could potentially meet the stated purpose and

need was developed. The Corps conducted public scoping meetings, consulted with state and Federal environmental and resource

agencies, and conducted technical studies to develop a range of conceptual alternatives that addressed the plan’s purpose and

need. Alternatives were developed from a combination of possible measures, as described in section 2.2. See Sec. 6.1 for further

discussion in scoping process. The process and criteria for screening the alternatives to determine whether they were

environmentally, economically, technically, and administratively feasible are described in section 2.3. The measures removed from

further consideration are discussed in section 2.4. Finally, sections 2.5, 2.6, and 2.7 present the alternatives that are evaluated in the

EIS, mitigation, and the Corps’ recommended plan, respective ly. The Corps also considered public comments submitted in

response to the Draft DMMP/EIS.

2.2 MEASURES CONSIDERED

Various measures or types of actions that addressed the program purposes were developed; often measures were combined.

Initially, non-structural measures were considered to meet the needs of maintenance of the navigation channel and related facilities

in all five reservoirs and to maintain the flow conveyance capacity of Lower Granite reservoir. These measures include land use

changes that would restrict the inflow of sediment and the possible use of in-water systems for control of sediment (such as bubble

curtains). Reservoir drawdown, a non-structural measure for providing flow conveyance, was also considered. Next, the traditional

method of dredging to meet the maintenance requirements and maintain the flow conveyance capacity of Lower Granite was

considered. Finally, construction of a sediment trap and levee modifications were considered. These plan measures are listed in

table 2-1 with an indication (noted by 4) of the program purposes that each address.

Table 2-1

Measures Addressing Program Purposes

Plan Measures

Program Purposes

Navigation Flow

Conveyance

Environmentally

Suitability

Change Upstream Land Uses √ √ √

Pool Drawdown √

In-Water Sedimentation Controls

• Bubble Curtain √

• Bendway Weir √ √

Dredging and Disposal of Dredged Materials

• Dredging with In-Water Disposal √ √ √

• Dredging with Upland Disposal √ √ √

• Beneficial Use √ √ √

Construct Upstream Sediment Traps √ √

Levee Modification √ √

To provide a baseline for consideration of the alternatives, and in accordance with the requirements of NEPA, a “No Action (No

Change)” alternative was considered. For the purposes of the DMMP/EIS, this alternative was a continuation of maintenance of the

authorized navigation channel as directed by Congress in PL 87-874 (see section 1.4) and related maintenance features in the five

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reservoirs.

These categories of methods are summarized in sections 2.2.1 through 2.2.6. Alternatives were developed and screened to evaluate

their feasibility, to determine which alternatives should be evaluated in the DMMP/EIS, and to select a preferred alternative, if

appropriate.

Characteristics of the dredging options are summarized beginning in section 2.2.4, followed by a discussion of the upland disposal,

beneficial uses, upstream sediment control structures, and levee modification measures. Summary descriptions of dredging

operations are included in appendix A, Hydrologic Analysis, and cost information for each measure is presented in appendix B, Cost

Estimates.

2.2.1 Change Upstream Land Uses and Land Management Practices to Control Sediment

Navigation channel and flow conveyance capacity in the lower Snake and Columbia River systems are, in part, reduced by eroded

sediments entering the systems from upstream sources. Similarly, sedimentation that has reduced flow capacity in the upstream

reach of the Lower Granite reservoir is a result of sediments flowing into the reservoir from the Snake and Clearwater Rivers.

Sediments enter the river systems through a number of sources. Some erosion occurs as a natural physical process; however, land

uses and land management practices also affect the amount of erosion and sediments entering the river system.

Studies have shown that non-irrigated cropland is a predominant land use in the watershed draining to Lower Granite reservoir and

is responsible for approximately 37 percent of the sediment yield to the Lower Granite reservoir (Reckendorf et al., 1988). Other

sources of sediment yield in the watershed include forest lands, streambank erosion, rangeland, irrigated farmland, and other land

uses. Best management practices, including modified timber harvesting practices, erosion and sedimentation controls, and

agricultural conservation reserve practices (e.g., creating riparian buffers, or removing highly erodable land from agricultural

production) can reduce sediments entering the river systems and draining to the lower Snake and Columbia Rivers. Reckendorf et

al. estimated in 1988 that implementation of Food Security Act conservation practices (e.g., the Conservation Program, which takes

highly erodable land out of production) could reduce the overall sediment yield to Lower Granite reservoir by up to 37 percent.

The Corps owns and, in most locations, manages shoreline lands along the lower Snake and Columbia Rivers. However, it is not

within the Corps’ authority to control land uses and land management practices in the vast majority of the watershed that drains to

the lower Snake and Columbia Rivers. While control of upstream land uses to control erosion and sedimentation is potentially part

of a strategy to reduce sedimentation. This measure was considered useful in minimizing the need for other measures to fully meet

the program purposes and was recommended for continued consideration and implementation through the LSMG.

2.2.2 Reservoir Drawdown

Reservoir drawdown was considered in two different ways to increase the flow conveyance capacity of the Lower Granite Dam

Project in the Snake and Clearwater Rivers confluence area. Lower Granite reservoir was designed to operate at a pool elevation of

733 feet msl, while allowing the safe passage of flows through the confluence area at or below elevation 738. Over time, the

sedimentation in the confluence area has affected the project’s ability to pass flows at or below elevation 738. To correct this loss of

conveyance capacity, first, an action, flow conveyance, was considered to draw the reservoir down in anticipation of high flows to

reduce the pool or backwater affects on channel flow in the confluence area. This action would result in greater channel

conveyance capacity with reduced water surface elevations and a lowered risk of flooding. Second, an action, sediment flushing, to

periodically lower the reservoir at regular intervals was considered to increase the flow velocities in the confluence area and flush

the sediments further down river to areas of excess conveyance capacity.

2.2.2.1 Flow Conveyance

The first drawdown measure considered to increase flow capacity at the confluence of the Clearwater and Snake Rivers adjacent to

Lewiston, Idaho, was to draw down the Lower Granite reservoir to allow the SPF flow to pass without exceeding elevation 738. Lower

Granite reservoir was designed to operate at a pool elevation of 733 feet msl, while allowing the safe passage of flows through the

confluence area at or below elevation 738. Over time, the sedimentation in the confluence area has affected the project’s ability to

pass flows at or below elevation 738. Model studies have shown that Lower Granite reservoir is still able to pass up to 300,000 cfs (8

495.1 m3/s) flows both while maintaining a water surface elevation at the confluence of the Clearwater and Snake Rivers of 738 feet

msl, and while maintaining 15 feet (4.6 m) of navigation clearance over the lock sills at Lower Granite. Flows above 300,000 cfs (8

495.1 m3/s), up to the SPF of 420,000 cfs (11 893.1 m3/s), are predicted to result in water surface elevations above 738 feet msl due

to the influence of post-construction sedimentation in the confluence area and the existing dam. Accordingly, a reservoir drawdown

would not lower the water surface elevation in the confluence area to or below 738 feet msl during flows of 300,000 cfs (8 495.1

m3/s) or greater.

2.2.2.2 Sediment Flushing

Drawdown of the Lower Granite reservoir below elevation 724 at the forebay, was considered for the purpose of flushing sediments

downstream thus improving conveyance capacity and reducing shoals in the confluence area. Reservoir drawdown that would scour

the historic river channel, thus potentially flushing sediments downstream, would be well below the authorized operating pool

elevation of Lower Granite reservoir and would severely impact project uses. Based on the 1992 Lower Granite Reservoir drawdown,

significant adverse impacts to public infrastructure (e.g., roads, drainage systems) and fish passage facilities at Lower Granite Dam

would result from substantial drawdown needed to flush sediments. A drawdown alternative would also have an adverse effect on

the navigation, causing a further reduction in the navigation clearances provided in the Lower Granite reservoir. This measure was

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eliminated from further consideration to meet the needs of this program.

2.2.3 In-Water Sedimentation Control

2.2.3.1 Bubble Curtain

Technologies are available that limit or prevent deposition of suspended sediments within a specific area. One such method involves

using air or water circulation in the water column to keep sediments from depositing within a protected area, thus minimizing the

need for dredging. Currently, the Port of Grays Harbor, Washington, uses this technology to prevent sedimentation around its

terminal ship berths. Also, an "air curtain" can be generated from a submerged perforated pipe to contain sediments and keep them

from settling.

This method is appropriate and effective for localized applications such as specific ports, boat basins, or other areas of limited size.

However, these methods are not particularly applicable to the scope of navigation channel maintenance contemplated in the

proposed plan. Use of either circulated water or air bubbles would require many miles of piping and numerous pumps and/or

compressors. It would also require nearly constant operation, resulting in localized noise, air quality impacts, and ongoing system

maintenance. Additionally, introduction of air into some areas of the lower Snake River would likely contribute to or exacerbate gas

saturation. For these reasons, the use of bubble curtains was dismissed as neither a feasible nor reasonable alternative to address

the plan’s purpose and need.

2.2.3.2 Bendway Weir

Another method of cont rolling the sedimentation of the navigation channels to reduce dredging is the use of Bendway weirs. A

Bendway weir is a well-engineered, environmentally sensitive approach to reducing streambank erosion and redirecting sediment

flow to reduce costly maintenance. The concept for Bendway weirs was developed by the Waterways Experiment Station in 1988

and has been used to realign and stabilize a number of streams and rivers across the United States, including the Mississippi River.

This method may have the potential to reduce the shoaling at critical points such as the Port of Clarkston navigation channel at RM

139 on the Snake River; however, it is not included as a part of the recommended plan without further consideration. The placement

of these rock weir structures requires considerable care to achieve overall reduction in the sedimentation of the navigation system

while avoiding adverse reductions in flow capacity. A successful weir installation requires thorough understanding of the Bendway

weir theory and extensive knowledge of the river location where the structure is to be placed. The method may warrant further

consideration as a method to prevent persistent shoaling, as experienced at the Port of Clarkston, but is not considered as a

method to be adopted throughout the system to reduce sedimentation. Although it is likely that Bendway weirs could be designed to

solve the local navigation problems, they would either trap additional sediment or move it only a short distance downstream. In

addition, the weirs themselves would raise the water-surface profile. While Bendway weirs do not represent substantial, complete,

or, in many cases, feasible stand-alone solutions to the issues addressed in the DMMP, the proposed adaptive management

program provides an opportunity for on-going evaluation of these and other measures to address sedimentation and dredged

material management issues. If this method were pursued, mathematical modeling of the hydraulic conditions with and without the

Bendway weirs in place would be required to ensure maintenance of the flow conveyance capacity.

2.2.4 Dredging and Disposal of the Dredged Material

A range of dredging and disposal measures has been considered in formulating the alternatives presented in this plan. Most of

these measures can be coupled with some degree of levee modification in the Lewiston-Clarkston area. The measures range from

dredging to maintaining the authorized navigation channel and related facilities in the five reservoirs to dredging up to 2 million cy (1

529 110 m3) annually in the main river channel for improvement of flow capacity. Increasing dredging amounts in the Lower Granite

reservoir at the confluence of the Clearwater and Snake Rivers was designed to provide proportionately increasing flow conveyance

in that area. Figure 2-2 presents a schematic comparison of channel maintenance for flow conveyance and navigation clearance.

Although the focus of the dredging program measures for increased flow conveyance is in the Lower Granite reservoir, the program

measures also consider dredging in the other reservoirs in the lower Snake River system to maintain the navigation channel. All

measures that contemplate volumes greater than that required for maintenance of the navigation channel apply only to the Lower

Granite reservoir. All dredging measures include the maintenance of the navigation channels and related facilities in all five

reservoirs with varying dredged material quantities for flow conveyance options in Lower Granite reservoir.

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Dredging would be performed using either mechanical or hydraulic methods. Mechanical dredging with a clamshell dredge would

be the preferred dredging method for the maintenance of the navigation channels and recreation facilities. Mechanical dredging

involves excavation of sediments. A "clamshell" dredge generally involves a crane-mounted, hinged bucket to scoop up and move

dredged material. Hydraulic dredging employs suction to move sediments. Hydraulic dredging may be considered for small areas

off the main river channel, such as irrigation intakes.

The NMFS and Washington Department of Fish and Wildlife have not allowed use of hydraulic dredging methods for over 10 years

because of concern for entrainment of juvenile ESA-listed endangered or threatened fish species. However, the agencies have

indicated they would consider the use of hydraulic dredging for small, off-channel areas on a case-by-case basis.

2.2.4.1 Dredging With In-Water Disposal

When determining options and criteria to use for in-water disposal of dredged material for beneficial use, the Corps reviewed a

study designed in 1987 by numerous scientists from federal, state, university and tribal entities. These entities included the Corps,

USFWS, NMFS, ESSA, Battelle-PNNL, WDFW, ODFW, University of Idaho, University of Washington, Oregon State University, and

the Yakima (now Yakama) Indian Nation (Web et al., 1987). The researcher involved with many of the studies was David Bennett,

Ph.D., a tenured professor at the University of Idaho. The multiple-year study design, a lead researcher independent from the

federal government, and study design from the region’s leading experts yielded scientifically sound results for consideration in

dredged material management planning as explained in the following sections.

Initially, in-water disposal of dredged material was considered to be in one of three types of areas: (1) shallow water, 0 to 20 feet (0

to 6.1 m) below the surface; (2) mid-depth water, 20 to 60 feet (6.1 to 18.3 m) below the surface; and (3) deep-water, 60 feet (18.3

m) and deeper. The selection criteria of the in-water disposal area usually included the physical characteristics of the material, the

potential to optimize the benefit to fish, and the absence of known cultural resource sites. Once materials were placed aboard the

bottom-dump barges, they would be judged for their suitability for use as fish habitat and assigned a disposal area. Samples taken

from the barge while loading would be used to determine the appropriate disposal area. This plan called for disposing of material

judged suitable for fish habitat, with at least 80 percent sand or larger [greater than 0.008 inch (0.2 millimeters (mm)) in diameter],

at a shallow- or mid-depth water disposal area. Sands, gravels, and cobbles are expected to comprise 85 percent of the total

dredged material. The remaining 15 percent of material that was silt or finer and, therefore, not suitable for fish habitat would be

deposited in deep water directly from bottom-dump barges beginning at the upstream end of the designated deep-water disposal

areas. Disposal of the silt in deep-water sites would have little impact, either positive or negative, on aquatic species. The capacities

of these disposal sites exceed the quantity of dredged material expected from all sources in the next 20 years. Small amounts of

material may require disposal at upland sites. While this plan would adequately dispose of the expected dredged material, it was

not considered the optimum plan because the Clean Water Act specifies that placing fill within the waters of the United States

should be avoided if there is a practicable alternative. However, Region 10 of the Environmental Protection Agency has stated that

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in-water disposal of dredged material would be acceptable if the material was used in a beneficial way.

A revised plan considered utilizing all of the dredged material for the creation of shallow water fish habitat rather than placing the

fine sediment in the deep portions of the reservoir. The fine grain silts would be used in a mixture with sands and gravels to fill

mid-depth areas and form the foundation for the later placement of sand and gravel for shallow-water habitat. In-water disposal

sites designated for each of the reservoirs included shallow-water and mid-depth disposal areas that had no known cultural

resource sites. The objective of this disposal plan is to establish shallow-water habitat from 0 to 20 feet (0 to 6.1 m) deep to restore

fish habitat. Equipment limitations may restrict the disposal of material to at or below -10 feet (-3 m) in the near-shore shallow areas.

While the formation of shallow water habitat of depths from 0 to 10 feet (0 to 3 m) is desirable, disposal of dredged material to form

these shallow areas would be restricted to sites identified as suitable to provide an environmental restoration opportunity and where

a sponsor is willing to share costs.

Juvenile fall chinook salmon prefer shallow, open sandy areas along shorelines for rearing (Bennett et al., 1997). Bennett et al.

(1998) showed that fall chinook salmon utilized the shallow-water habitat created with in-water disposal of dredged material that

surrounds Centennial Island in Lower Granite reservoir, near RM 120. In some years, as many as 10 percent of the total sample of

subyearling chinook salmon from Lower Granite reservoir originated from the habitat created by in-water disposal. Bennett et al.

(1998) reported that fall chinook salmon were most commonly collected over lower gradient shorelines that have low velocities and

sandy substrate. Habitat having these physical characteristics can be effectively constructed in any of the lower Snake River

reservoirs with appropriate placement of dredged material.

Differences in habitat suitability exist for habitat created by dredged material depending upon substrate size. For example, at the

Centennial Island site in Lower Granite reservoir, the shoreward station with sandy substrate often supported a different fish

community structure than that from the channel side that was armored with cobble/boulders to secure the shoreline. Species that

prefer larger substrate, such as smallmouth bass, were consistently collected in higher abundance along the large substrate than in

the area with finer substrate, without armoring of larger substrate. Therefore, preliminary data suggest that fish community structure

can also by "fine tuned" with manipulation of the size of substrate as well as changes in depth.

A contingency upland disposal site has also been identified for each alternative to provide storage for a portion of dredged material

that may, for whatever reason, need to be deposited on a separate upland site. In the event that dredged material may be

unsuitable for in-water disposal (e.g., dredged material that may contain low levels of contaminants that prohibit its use for in-water

habitat creation, but would not otherwise be considered solid or hazardous waste), it would be placed at the Joso upland disposal

site, and appropriate confinement measures would be taken to isolate it.

The Joso upland disposal contingency site is located on the south shore of the Snake River between RM 56.5 and RM 58.6, in the

Lower Monumental reservoir (plate 11). This document presents the conceptual design for development of this site and disposal

plans for dredged material at this site should the need occur in the future. The Joso site is designated as a wildlife HMU, but was

formerly used as a borrow site and contains a gravel pit at its center. It is estimated that this site can accept the full amount of

material from all five reservoirs through the 20-year life of this DMMP/EIS. The initial construction of the site would include

reestablishing the barge berth at the west end of the site. A temporary storage area would be developed by constructing a

containment berm around an area adjacent to the barge berth. Permanent disposal would be developed in the old gravel pit area in

the center of the Joso site. Dredged material would be off- loaded at the site using a barge- mounted crane and mobile transport

equipment to haul material from temporary storage to the permanent disposal site. The Corps would conduct tests on material to be

dredged and prepare final design of the permanent disposal features before disposing of material at the Joso site.

Below are descriptions of the four options of dredging that were considered for this DMMP/EIS. The main differences between the

options are the quantity of material to be dredged and the dredging template design.

2.2.4.1.1 Navigation and Facility Maintenance Dredging

Dredging Areas. The maintenance dredging area is the current authorized navigation channel for the lower Snake River and McNary

reservoirs and maintenance of public recreation areas, such as swimming beaches and boat basins, and irrigation intakes for wildlife

HMU's managed by the Corps.

Dredging Template Design. As noted above, the dredging template is based on the authorized navigation channel, public recreation

areas, and irrigation intakes for HMU's. The authorized navigation channel is 250 feet (76.2 m) wide and 14 feet (4.3 m) deep for all

five reservoirs. The template would not extend down into original riverbed or shoreline material.

Disposal Sites. In-water locations for shallow, mid-depth, and deep water dredged material disposal are identified in each of the five

reservoirs. In-water disposal areas in Ice Harbor and Lower Granite reservoirs used in the recent maintenance dredging operations

have created mid-depth and shallow-water sites. The methods used in these latest disposal operations would be employed in this

base plan and applied to all five reservoirs. Dredged material containing sand, gravel, and cobbles would be disposed of in either

mid-depth, as a base, or shallow water to create shallow water habitat. Silts and fine material would be restricted to disposal at

mid-depth sites. Collectively, the designated in-water disposal sites have adequate capacity to contain all materials dredged under

this option.

Upland disposal may be used for some of the recreation area dredging and irrigation intake dredging on a case-by-case basis.

Disposal would likely be adjacent to the dredging site.

Material Types and Volume. Dredged materials consist of silts, sands, gravels, and cobbles. Historically, composition of dredged

material from the study area has been approximately 85 percent sand, gravels, and cobbles, and approximately 15 percent silts and

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fines. A volume of dredged material up to 340,000 cy (259 948.7 m3) would be dredged from the five reservoirs about every 2 years

over the next 20 years for a total volume of up to 3,400,000 cy (2 599 487 m3) of dredged material.

Program Schedule and Duration. For planning purposes, it was assumed that maintenance dredging using a clamshell dredge

would be conducted every 2 years in each reservoir. However, the length of time between actual dredging operations will vary

depending on sediment inflow and deposition. Dredged materials would be transported by bottom-dump barge to the appropriate

in-water disposal sites. Dredging would usually occur between December and March 1 in the Snake River and between December 1

and March 31 in the Columbia River during periods (windows) established to minimize the impacts on ESA- listed endangered or

threatened anadromous fish species. Dredging in the summer, possibly in August, would be considered on a case-by-case basis for

off-channel dredging. Dredged material containing predominantly sands, gravels, and cobbles would be transported by

bottom-dump barge to the shallow and mid-depth areas for in- water disposal. Barges containing silt and other fines would be

restricted to disposal at mid-depth sites. A minimum water depth of 15 feet (4.6 m) is required for bottom-dump barges to access the

disposal sites. Disposal would be done by bottom-dump barge at a rate of approximately 15,000 cy per acre (28 338 m3 per hectare)

to create shallow water habitat with a minimum depth of 10 feet (3 m). A drag beam or some other device would be used to smooth

the surface of the material dumped from the bottom-dump barges. Figures 2-3 and 2-4 illustrate the disposal process. Channel

maintenance average annual costs are estimated at $560,000 computed over the 20-year period at a 6.875 percent interest rate.

This cost estimate is based on maintaining the authorized navigation channel dimensions over the next 20 years using clamshell

dredging, bottom-dump barges, and in-water disposal of the dredged material. Use of hydraulic equipment was not considered

acceptable because of the anticipated adverse impact on endangered fish resources. Disposal at upland sites instead of in-water

sites was considered, but found to be more costly and provide less environmental benefit than in-water disposal.

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2.2.4.1.2 Dredge 300,000 cy Per Year

Dredging Areas. This option would meet the requirements for navigation maintenance in each of the five reservoirs as well as

improve the flow conveyance capacity of the Lower Granite reservoir. Dredging to improve flow conveyance capacity would be

conducted only in the Lower Granite reservoir. Navigation maintenance dredging described above would remain unchanged.

Dredging in Lower Granite reservoir would extend from the Port of Wilma near Snake RM 134 to the U.S. Highway 12 bridge located

upstream of the confluence of the Snake and Clearwater Rivers, near Snake RM 139.5. The Clearwater River dredging would

extend from the Snake River confluence upstream approximately 1.5 miles (2.4 km) to the Port of Lewiston.

Dredging Template Design. Dredging templates for all of the reservoir areas except the Snake/Clearwater Rivers confluence area of

the Lower Granite reservoir would remain the same as the navigation and facility maintenance dredging option. The

Snake/Clearwater Rivers confluence area dredging template would increase in size and vary in width from 300 feet (91.4 m) near

the Port of Wilma to 1,700 feet (518.2 m) in the Clearwater River confluence area. This portion of the template is a large volume to

be dredged over multiple years to improve flow conveyance as well as provide navigation clearances. The average dredging width

on the Snake River within this area would be 750 feet (228.6 m). The average depth of dredging on the Snake River would be

approximately 10 feet (3 m) below the elevation of the bottom of the river channel as it existed in 1997 and would extend down into

original riverbed or shoreline material.

Disposal Sites. Disposal areas for all reservoirs would remain the same as the navigation and facility maintenance dredging option

and have adequate capacity to contain all materials dredged under this option. In-water disposal in Lower Granite reservoir would

be accomplished downstream of Centennial Island near Snake RM 120.4.

Material Types and Volume. Dredged materials would be composed of a mixture of silts, sands, gravels, and cobbles. Approximately

6.4 million cy (4.9 m3) would be dredged from the five reservoirs over the next 20 years and 23.1 million cy (17.6 m3) between the

years 2002-2074. Program Schedule and Duration. Dredging would usually occur from December 15 to March 1 for the Snake River

reservoirs and December 1 to March 31 for the McNary reservoir. Dredging in the summer, possibly in August, would be considered

on a case-by-case basis for off-channel dredging.

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Approximately 300,000 cy (229 366.5 m3) of material would be dredged annually throughout the study period from the Lower Granite

reservoir for flow conveyance and navigation maintenance dredging. Navigation channel maintenance dredging of 40,000 cy (30

582.2 m3) from the other four reservoirs would occur about every 2 years, as previously described. The average annual cost of this

measure computed over the period 2001 to 2074 at 6.875% interest is $1,233,000.

2.2.4.1.3 Dredge 1 Million cy (764 555 m3) Per Year

Dredging Areas. This option would meet the requirements for navigation and facility maintenance in each of the five reservoirs as

well as improve the flow conveyance capacity of the Lower Granite reservoir. Only the Lower Granite reservoir dredging area and

template would change. Dredging in the Lower Granite reservoir would extend from the Port of Wilma near Snake RM 134 to the

U.S. Highway 12 bridge located upstream of the conflue nce of the Snake and Clearwater Rivers, near Snake RM 139.5. The

Clearwater River dredging would extend from the Snake River confluence upstream 1.5 miles (2.4 km) to the Port of Lewiston.

Navigation maintenance dredging of the channel would occur in the other reservoirs.

Dredging Template Design. The dredging template would be the same as the 300,000 cy (229 366.5 m3) alternative. The

Snake/Clearwater Rivers confluence area dredging template varies in width from 300 feet (91.4 m), near the Port of Wilma, to 1,700

feet (518.2 m) in the Clearwater River confluence area. The average dredging width on the Snake River within this area would be

750 feet (228.6 m). The average depth of dredging on the Snake River would be approximately 10 feet (3 m) below the elevation of

the bottom of the river channel as it existed in 1997 and would extend down into original riverbed or shoreline material. It would take

fewer years to remove material from the template than for the 300,000 cy (229 366.5 m3) dredging alternative.

Disposal Sites. Disposal sites identified in the navigation and facility maintenance dredging option are adequate to contain all

materials dredged under this option.

Material Volume and Types. Dredged materials would be composed of a mixture of silts, sands, gravels, and cobbles. Approximately

13.7 million cy (10 474 400 m3) would be dredged from the five reservoirs over the next 20 years and more than 31.8 million cy

(24,351,210 m3) dredged between the years 2001 and 2074 under this option.

Program Schedule and Duration. Dredging would usually occur from December 15 to March 1 for the Snake River reservoirs and

December 1 to March 31 for McNary reservoir. Dredging in the summer, possibly in August, would be considered on a case-by-case

basis for off-channel dredging. Approximately 1 million cy (7 64 555 m3) of material would be dredged annually from Lower Granite

reservoir for a 10-year period to establish the Lower Granite dredging template area described above. The dredging activity would

then drop back to 325,000 cy (248 480 m3) annually for the remainder of the study period through the year 2074 to ensure the

template is maintained for the period. For planning purposes, it was assumed that navigation channel maintenance dredging of

40,000 cy (30 582.2 m3) from the other four reservoirs would occur every 2 years. The average annual cost of this measure is

$1,911,000 when computed at 6.875% interest over the period 2001 to 2074.

2.2.4.1.4 Dredge 2 Million cy (1 529 110 m3)Per Year

Dredging Areas. This option would meet the requirements for navigation and facility maintenance in each of the five reservoirs as

well as improve the flow conveyance capacity of the Lower Granite reservoir. Only the Lower Granite reservoir dredging area and

template would change from the 1 million cy (764 555 m3) per year measure. Dredging in the Lower Granite reservoir would extend

further downstream from the vicinity of Silcott Island near Snake RM 131 upstream to the U.S. Highway 12 bridge upstream of the

confluence of the Snake and Clearwater Rivers, located near Snake RM 139.5. The Clearwater River dredging areas extend from

the Snake River confluence upstream to the Port of Lewiston at Clearwater RM 1.66.

Dredging Template Design. The proposed Lower Granite reservoir template on the Snake River is larger than the previous

alternative and would vary in width from 600 feet (182.9 m) near Silcott Island to 1,700 feet (518.2 m) in the confluence area. The

average width on the Snake River is 950 feet (289.6 m). The Clearwater dredging template varies in width from 300 feet (91.4 m)

near the Camas Prairie Railroad bridge crossing to 1,000 feet (304.8 m) in the Port of Lewiston turning basin. The average width is

750 feet (228.6 m). The average depth of dredging would be 20 feet (6.1 m) below the elevation of the bottom of the river channel as

it existed in 1997 and would extend down into original riverbed or shoreline material.

Disposal Sites. Disposal sites identified in the navigation and facility maintenance dredging option (section 2.2.4) would be adequate

to contain all materials dredged under this option.

Material Types. Dredged materials would be composed of a mixture of silts, sands, gravels, and cobbles. Approximately 40.4 million

cy (30.9 m3) would be dredged from the five reservoirs in the next 20 years and approximately 79.2 million cy (60.6 m3) between the

years 2001 and 2074 under this option.

Program Schedule and Duration. Dredging would usually occur from December 15 to March 1 for the Snake River reservoirs and

from December 1 to March 31 for the McNary reservoir. Dredging in the summer, possibly in August, would be considered on a

case-by-case basis for off-channel dredging. Approximately 2 million cy (1.5 m3) of material would be dredged annually for a 20-year

period to establish the dredging template area described above. The dredging activity would then be reduced to 725,000 cy (554

302.3 m3) annually for the remainder of the study period through the year 2074 to ensure the dredging template remains clear of

sediment. For planning purposes, it was assumed that dredging of 40,000 cy (30 582.2 m3) total from the other four reservoirs would

occur about every 2 years. The average annual cost of this measure when computed over the period of 2001 to 2074 at 6.875%

interest is $4,706,000.

2.2.4.2 Dredging with Upland Disposal

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This measure employs the same dredging equipment and operation methods as the previous measures, but uses a standard barge

240 feet (73.2 m) long by 42 feet (12.8 m) wide to transport the dredged material. The dredged material would either be transferred

directly to an upland disposal site or stockpiled at a temporary site for future transfer to a permanent upland disposal site. This

measure includes navigation and facility maintenance dredging in the McNary reservoir and in the four lower Snake River reservoirs.

As part of the DMMS process, the Corps identified multiple upland sites on each reservoir that could potentially serve as dredged

material disposal areas. A preliminary screening of these sites was conducted to assess their feasibility and/or suitability to serve as

sites for upland disposal of dredged material. This screening process narrowed the list of potential sites to a total of 10 sites: a

primary and secondary upland site in each of the five reservoirs. Anticipated costs and impacts of these 10 primary and secondary

sites were used to further screen and narrow the list of potential upland sites to three: the Joso site (plate 11) and Page Creek

disposal site (1 mile south of Snake RM 131), and the Chief Timothy "transfer site" (Snake RM 130.5).

All upland disposal options would include a contingency upland disposal site, similar to the in-water options, for material found

unsuitable for disposal in the standard upland disposal site. This site has been identified as Joso (plate 11), located on the south

shore of the Snake River (between RM 56.5 and RM 58.6) in the Lower Monumental reservoir.

The alternatives that involve upland disposal of va rying dredged material volumes are described below.

2.2.4.2.1 Navigation and Facility Maintenance Dredging

All material would be disposed in the Joso upland disposal site. The Joso site is located along the southern shore of the Snake

River between RM 56.5 and RM 58.6, in the Lower Monumental reservoir. The site is bounded on the south side by the Union Pacific

Railroad. The entire site is approximately 568 acres (229.9 hectares) and is constrained by a habitat area approximately 600 feet

(182.9 m) wide along the Snake River site boundary and by wetlands in the eastern corner. With the 600- foot (182.9- m) riparian

boundary protected, the Joso site provides a barge slip, material unloading areas, and an area of approximately 280 acres (113.3

hectares) for permanent disposal of dredged material. A portion of the permanent disposal area would be set aside as a confined

area, with a liner, to accommodate the material found to be unsuitable for disposal in the standard upland disposal area.

The Joso site would receive dredged material by barge and permanently store up to 6.4 million cy (4.9 m3) of material. The site is

adequate to hold all of the navigation and facility maintenance dredged material from the five reservoirs over the 20-year

maintenance period. Barge access to the site would be provided by reestablishing the berth at the west end of the site. Anchored

sheet pile walls would be used along the barge slip sides to provide vertical wall docking surfaces and to retain the adjacent

platform walls. Barge tie-offs would be constructed at the top of the slip adjacent to the sheet pile. Temporary dredged material

dewatering and storage areas with containment berms and detention ponds would be developed adjacent to the slips. Material

handling at the Joso site would include off- loading of dredged material from the barges using cranes on rubber tires. The material

would be placed in the temporary storage area adjacent to the barge slip for dewatering and loading onto trucks for transport into

the disposal area. The material would then be placed in lifts with track-type tractors and compacted, resulting in a large structural fill

conforming to the established final topography for the disposal area. All disposal activities would avoid known cultural resource

sites. Areas that reach final grades would be restored on a periodic basis by placing 6 inches (15.2 cm) of topsoil and re-seeding to

achieve a vegetative cover similar to surrounding site areas. A conceptual site layout for the Joso site is presented in figure 2-5 and

described in detail in appendix D, Upland Disposal Conceptual Design.

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2.2.4.2.2 Dredge 300,000 cy Per Year

For the first 20 years of the program, most material dredged under this option would be deposited in the Joso site. At the conclusion

of the 20-year period, the Joso site would be filled to capacity and another site would have to be developed.

The Page Creek site in Lower Granite reservoir would be used to hold the remaining material once Joso is filled. The Page Creek

disposal site is located approximately 1.5 miles (2.4 km) south of the Snake River adjacent to Page Creek near the mouth of Alpowa

Creek, downstream of Snake RM 130. The entire site is approximately 985 acres (398.6 hectares), but only a portion of the site, at

the northern end, would be used for disposal of dredged material. The site has a capacity of 80 million cy (61 164 390 m3) and is

capable of containing all the material expected to be dredged for all alternatives considered over the life of the project to year 2074.

The site has a plateau on the northern portion that is presently used for agricultural crops. The remainder of the site has relatively

steep slopes from the plateau down to Page Creek, a drop of about 600 vertical feet (182.9 vertical meters). Dredged material would

be placed in lifts starting at the lower end of the northerly portion of the site and would progressively fill the site in a southerly

direction. Fill placement operation would use track-type tractors and steel- wheeled compactors. The disposal and fill construction

operation would take place throughout the year. Site restoration would occur periodically throughout the life of the fill construction.

Use of the Page Creek site would require development of a transfer facility on the left bank of the Snake River, located adjacent to

Chief Timothy State Park at RM 131, that would allow barge off- loading, staging of dredged material, and facilities for transporting

material across U.S. Highway 12 to the Page Creek site. The Chief Timothy transfer site was proposed to meet this need. The Chief

Timothy site, an open water embayment, is an area of about 66 acres (26.7 hectares) in 21 feet (6.4 m) of water located at the

mouth of Alpowa Creek in the Snake River. The facility would consist of a rock berm around the site perimeter with a top elevation 3

feet (0.9 m) above normal operating pool for the Lower Granite reservoir. The interior of the berm would be filled with approximately

2 million cy (1 529 110 m3) of dredged material to form a platform of dredged material for a temporary storage area. A barge

berthing area would be developed and gantry-type cranes installed for off- loading barges. The transfer of up to 2 million cy (1 529

110 m3) per year of dredged materials to the Page Creek disposal site would require the construction of a bridge across U.S.

Highway 12. The Page Creek and Chief Timothy sites are described in more detail in appendix D, Upland Disposal Conceptual

Design. The average annual cost of this measure computed over the period 2001 to 2074 at 6.875% interest is $5.6 million.

2.2.4.2.3 Dredge 1 Million cy (764 555 m3) Per Year

This plan would use the Chief Timothy transfer site and the Page Creek disposal site for dredged material from Lower Granite

reservoir for the entire period. The Joso site would be used for disposal of dredged material from McNary, Ice Harbor, Lower

Monumental, and Little Goose reservoirs. The average annual cost of this measure computed over the period 2001 to 2074 at

6.875% interest is $6.8 million.

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2.2.4.2.4 Dredge 2 Million cy (1 529 110 m3) Per Year

This plan would use the Chief Timothy transfer site and the Page Creek disposal site for dredged material from Lower Granite

reservoir for the entire period. The Joso site would be used for disposal of dredged material from McNary, Ice Harbor, Lower

Monumental, and Little Goose reservoirs. The average annual cost of this measure computed over the period 2001 to 2074 at

6.875% interest is $19.3 million.

2.2.4.3 Beneficial Use of Dredged Material

Dredged material can be used to benefit and restore the environment. This use is consistent with Corps policy to secure the

maximum practicable benefits through the use of material dredged from navigation channels. Opportunities to use dredged material

beneficially become available over time and cannot be anticipated in a programmatic document such as this. In order to be able to

take advantage of such beneficial uses, this document sets forth a process to identify and evaluate the opportunities as each major

dredging activity is being planned. Part of this process is the formation of an LSMG that would help identify beneficial uses such as

creation of aquatic and wildlife habitat, replenishment of beaches, or filling of upland sites.

The LSMG described in section 1.8 would provide an interagency approach to management of dredged material including definition

of disposal plans coordinated with and amenable to the public stakeholders and resource agencies. In accomplishing this function,

the LSMG would facilitate a process involving participation of affected agencies, organizations, and groups to identify and

recommend the most environmentally sound and practical beneficial use of dredged material for each major dredging activity.

Each time a dredging activity covered under this DMMP/EIS is planned, the following steps would be followed:

The Corps would notify parties such as the ports, municipalities, environmental groups, agencies, and others known to have

an interest in the beneficial use of dredged material. The Corps would provide the location, estimated quantity, dredging

method, expected characteristics of dredged material and estimated time of the dredging activity. The Corps notification would

precede the proposed dredging activity by allowing sufficient time to negotiate an agreement with a local sponsor for the

beneficial use of the dredged material.

A public notice would be published and distributed prior to the dredging activity. Beneficial uses defined by this process may

be achieved when a local sponsor is willing to contribute a share of the cost. Table 2-2 describes the various measures and

cost-sharing options that apply to the beneficial use of dredged material.

.

Table 2-2

Cost Sharing of Beneficial Use of Dredged Material

Purpose Authority

Cost Share %

(Fed./Non-Fed.)

Creation of Land Section 101 of Water Resources Development Act of 1986 0/100

Restoration and Nourishment of Beaches Section 933 of Water Resources Development Act of 1986 50/50

Protection, Restoration, and Creation of

Aquatic and Ecologically Related Habitats,

Including Wetlands

Section 204 of Water Resources Development Act of 1986 75/25

The cost of a "beneficial use of dredged material" project is determined to be the difference in disposal costs of the "beneficial use

project" compared to the cost of the least-cost, environmentally acceptable dredged material disposal option. This DMMP/EIS

identifies the basis for determining the least-cost option for dredged material disposal. At any time, the Corps can identify another

beneficial use, and the non-Federal interest would be given reasonable opportunity to finance the additional cost.

In specific circumstances, the Corps has the authority and appropriations to go forward with a beneficial use without a local sponsor

(i.e., woody riparian).

The opportunities that currently exist and were considered for early implementation are presented section 2.5.4.

2.2.4.4 Emergency Dredging

Under any dredging and dredged material disposal measure considered, the Corps may need to perform dredging on an

emergency basis. An emergency, as defined in 33 CFR 335.7, Operation and Maintenance of Army Corps of Engineers Civil Works

Projects Involving the Discharge of Dredged or Fill Material into Waters of the U.S. or Ocean Waters, is a situation that would result

in an unacceptable hazard to life or navigation, a significant loss of property, or an immediate and unforeseen significant economic

hardship if corrective action is not taken within a time period less than the normal time needed under standard procedures.

There are several potential situations that could occur in the Snake and Columbia Rivers that may require emergency dredging.

High flows could deposit enough sediment at a point or points in the Federal navigation channel to block navigation. Rock could be

swept into the navigation lock approach and form a shoal or sediment could build up on the inside bend of the navigation channel,

posing an unacceptable navigation hazard.

For an emergency dredging situation, the Corps would perform environmental coordination on an expedited basis. The Corps would

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perform as much coordination as possible before initiating the emergency dredging, but some coordination may be performed

during the dredging or after the dredging is completed.

2.2.5 Construct Upstream Sediment Traps

A qualitative evaluation of sediment control structures was conducted to assess structures that might provide sufficient control of

sediment transport on the Clearwater and Snake Rivers. The objective was to identify structures that reduce the sediment load

sufficiently to avoid dredging and/or levee raises in the Lewiston-Clarkston area. This, in turn, would mitigate the probability of

flooding due to sediment deposition. Sediment control structures must slow velocities for a sufficient length of time to allow

sediment to drop out of the water column and be deposited behind the control structures.

The U.S. Geological Survey (USGS) has estimated the amount of sediment being transported annually to be 1.9 million tons (1.72

million metric tons) in the Snake River at Lewiston, and 0.47 million tons (0.43 million metric tons) in the Clearwater River. Sediment

sampling in Lower Granite reservoir found that approximately 95 percent of the sediments being deposited are fine- grained

materials [typically smaller than 0.01 inch (0.25 mm)]. The relatively small size of the sediment material suggests that a submerged

structure, such as a silt trap, would be marginally effective. The Corps investigated the possibility of dredging an area of the Snake

River sufficiently to form a reservoir of slack water where sediments could settle. These investigations determined that the amount of

material that would need to be dredged was so great that the scenario was determined impracticable. Data also suggests that the

existing dams and reservoirs on the lower Snake River retain approximately 80 percent of the sediments that enter the reservoir. It is

unlikely that a new structure would be capable of better performance.

Estimates imply that removal of 80 percent of the sediment transported down the Snake River [approximately 1.5 million tons (1.36

million metric tons) per year] would be sufficient to mitigate sediment deposition concerns in the Lewiston-Clarkston area, excepting

some deposition in a few areas that would adversely affect barge traffic. Therefore, it would not be necessary to construct structures

on both the Snake and Clearwater Rivers.

The dredged material removed from the navigation channels in Lower Granite reservoir are composed of 85 percent sand, gravels,

and cobbles and 15 percent finer silt material. This would suggest that the majority of the material entering this reservoir as silt does

not contribute significantly to shoaling of navigation channels. This silt is either deposited in other portions of the reservoir or

relocated by prop wash from navigation activities, eliminating it from the navigation channels. Since the larger materials (sand,

gravels, and cobbles) are the sediment of primary concern to navigation channels, it is assumed that a smaller sediment trap might

be capable of trapping a sufficient amount to be an economical alternative to dredging the channel. However, the legislative history

concerning further structures on the Snake River for this purpose would indicate that this is not an acceptable alternative.

It is clear from the legislation passed since the authorization of Asotin Dam that Congress now intends no further Federal dam

structures immediately upstream of Lower Granite on the Snake River. Portions of both the Snake and Clearwater Rivers have been

identified in the Wild and Scenic River Act [PL 90-542, as amended, 16 United States Code (U.S.C.) 1271-1287] as rivers with

sections that have been protected from further development or have qualities that make them candidates for protection. Public Law

94-199, dated December 31, 1995, de-authorized Asotin Dam because of its location with respect to the Hells Canyon National

Recreation Area. Public Law 100-677, dated November 17, 1988, further prohibits the licensing of any dam, diversion, or bypass

under the Federal Power Act on the Snake River above Lower Granite reservoir including the Asotin Dam site.

In addition to the clear legislation prohibiting Federal involvement, local, state, and Federal regulators indicate that there is no

adequate justification for constructing a sediment detention structure on the Snake River near Asotin. The plan to construct a

sediment detention structure has, therefore, been removed from further consideration.

2.2.6 Levee Modification

The cities of Lewiston and Clarkston are adjacent to the Lower Granite reservoir. Lewiston is protected by a backwater levee system

installed in lieu of relocating its business district. The levee system is an upstream extension of the dam and was designed to allow

the Lower Granite reservoir to be operated to protect the Lewiston and Clarkston area from inundation during the SPF.

The upper reach of the Lower Granite reservoir collects much of the sediment carried in suspension in the free- flowing reaches of

the upstream rivers. Sediment accumulation in the reservoir over time has reduced the flow conveyance capacity in this upper reach

and has compromised the level of protection provided by the levees. Dredging has been performed over the recent past to restore

and retain flow capacity in this upper reach of Lower Granite reservoir.

Consideration was given to a variety of levee modifications including raising the levees and moving the levees back from the river to

allow for a greater flow conveyance. Four levee modification plans were selected for further consideration based on their ability to

provide the flow conveyance capacity most effectively with the least impacts. Concept designs and cost estimates were developed

for the four levee raises, nominally identified as 12- foot (3.7-m), 8-foot (2.4- m), 4-foot (1.2- m), and 3- foot (0.9- m) raises, and the

increased flow conveyance capability has been identified for each.

The following sections describe each of the levee raise plans.

2.2.6.1 The 12-Foot (3.7-m) Levee Raise

The 12- foot (3.7- m) levee raise involves constructing bin walls and earth embankment raises of existing levees, extending the

existing levees in certain areas, and constructing new levees in some locations. The plan would include:

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Raising a portion of the west, east, and north Lewiston levees and building a new levee at the city of Asotin.

Modifying U.S. Highway 12, County Road 900 along the north bank of the Snake River opposite Clarkston, Highway 129 along

the west bank of the Snake River at Clarkston, Red Wolf Bridge access in northwestern Clarkston, Snake River Avenue along

the east bank of the Snake River at Lewiston, and the Snake River Road above Asotin.

Implementing changes to the Clarkston Sewage Treatment Plant, Asotin Sewage Treatment Plant, Lewiston Sewage

Treatment Plant, and Lewiston Water Intake.

Raising the U.S. Highway 12 bridge between Lewiston and Clarkston, the Camas Prairie Railroad (CPRR) bridge crossing the

Clearwater River at Lewiston, the Memorial Bridge over the Clearwater River at Lewiston, the Asotin Memorial Bridge, the

Highway 129-10 bridge, and the pedestrian bridge.

Raising the CPRR track in Lewiston.

Decreasing the risk of flooding to facilities including, but not limited to, the Ports of Wilma, Lewiston, and Clarkston.

Increasing the risk of flooding at the following recreational areas: Hellsgate State Park on the Snake River opposite Asotin,

Swallows Park between Asotin and Clarkston, Chief Timothy State Park on the south bank of the Snake River west of

Clarkston, the county boat ramp on the north bank of the Clearwater River near RM 3, bike and walking trails along many of

the levee segments, and the Clarkston Golf Course at the west end of Clarkston; as well as Rooster’s Landing Restaurant, the

convenience store and restaurant at Hellsgate State Park, a U.S. Forest Service building at Swallows Park, and the Corps’

resource buildings at Clarkston.

Possibly purchasing several residences along Highway 129.

The construction cost estimate for this plan is $87,661,500. The details for this plan are presented in appendix E, Lewiston Levee

Modification Extension Analysis.

2.2.6.2 8-Foot (2.4-m) Levee Raise

The 8- foot (2.4- m) levee raise involves constructing bin walls and raising the earth embankment of existing levees, extending some

existing levees, and constructing new levees in some locations. The plan includes:

Raising the west, east, and north Lewiston levees and building a new levee at the City of Asotin.

Modifying U.S. Highway 12, County Road 900, Highway 129, Snake River Avenue, and Snake River Road above Asotin.

Implementing changes to the Asotin Sewage Treatment Plant and Lewiston Sewage Treatment Plant.

Raising the U.S. Highway 12 bridge between Lewiston and Clarkston, the CPRR bridge, the Memorial Bridge, the Asotin

Memorial Bridge, the Highway 129-10 bridge, and the pedestrian bridge.

Raising the CPRR track.

Decreasing the risk of flooding to facilities including, but not limited to, the ports of Wilma, Lewiston, and Clarkston.

Increasing the risk of flooding at the following recreational areas: Hellsgate State Park, Swallows Park, Chief Timothy State

Park, the county boat ramp on the Clearwater River near RM 3, and bike and walking trails along the levees, as well as

Rooster’s Landing Restaurant, the convenience store and restaurant at Hellsgate State Park, the U.S. Forest Service building,

and the Corps’ resource buildings.

The construction cost estimate for this plan is $50,999,500. Details are presented in appendix E, Lewiston Levee Modification

Extension Analysis.

2.2.6.3 4-Foot (1.2-m) Levee Raise

The 4-foot (1.2-m) levee raise involves constructing bin walls and raising the earth embankment of existing levees. The plan would

include:

Raising a portion of the west and north Lewiston levees.

Modifying Highway 129 and Snake River Road above Asotin.

Raising the U.S. Highway 12 bridge between Lewiston and Clarkston, the Camas Prairie Railroad (CPRR) bridge, and the

Memorial Bridge.

Decreasing the risk of flooding to facilities at the Port of Lewiston.

Increasing the risk of flooding at the following recreational areas: Hellsgate State Park and Swallows Park, as well as Rooster’s

Landing Restaurant, the convenience store at Hellsgate State Park, the U.S. Forest Service building, and the Corps’ resource

buildings.

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The construction cost estimate for this plan is $15,623,500. The details for this plan are presented in appendix E, Lewiston Levee

Modification Extension Analysis.

2.2.6.4 3-Foot (0.9-m) Levee Raise

The 3- foot (0.9- m) levee raise involves adding an earth embankment raise to existing levees. The plan would include:

Raising a portion of the west Lewiston levee.

Modifying Highway 129 and the Snake River Road upstream of Asotin.

Increasing the risk of flooding at the following recreational areas: Hellsgate State Park and Swallows Park, as well as the

convenience store at Hellsgate State Park, the U.S. Forest Service building, and the Corps’ resource buildings.

The construction cost estimate for this plan is $2,273,500. Details are presented in appendix E, Lewiston Levee Modification Extension

Analysis.

2.3 FORMULATION OF ALTERNATIVES TO BE CONSIDERED IN DETAIL

2.3.1 Screening Process

The screening process consisted of formulating alternatives from the most viable program measures discussed in section 2.2,

evaluating each alternative, and selecting alternatives for further detailed consideration. Preliminary evaluation criteria were

developed to determine the alternatives that were feasible, reasonable, and should be considered in detail. These criteria

considered whether:

The alternatives were cost-effective, while either providing environmental benefits or causing the least environmental damage.

The alternatives provided a way to regain and/or maintain channel capacity to provide an acceptable level of flow conveyance

capacity resulting in flood protection (based on the results of a risk-based analysis) in the Lewiston-Clarkston area.

The alternatives have acceptable impacts on other project uses (such as shippers and recreational users).

A set of detailed screening criteria was then developed to evaluate the relative impacts, costs, and/or benefits of a set of dredging

and levee alternative combinations. Use of these criteria in an evaluation process facilitated a selection of alternatives that were

considered feasible, reasonable, and would be evaluated in detail in the EIS. An initial set of 12 dredging and levee alternatives

included the "No Action (No Change) alternative" and combinations of dredging and levee raises. Ten alternatives go beyond

navigation maintenance by combining increased dredging and levee raises to meet approximately the same levels of navigation and

flow conveyance needs. The methodology and criteria used to evaluate each of the 12 alternatives against the screening criteria are

discussed below.

2.3.2 Methodology and Evaluation Criteria

A set of evaluation criteria was established that allowed an across-the-board comparison of the 12 alternatives. The criteria were

chosen because they represented key indicators of environmental impacts and economic benefits and costs. These criteria also

pointed out potential "fatal flaws" in an alternative and allowed a planning- level comparison of the alternatives. Using this process,

high-cost, high- impact alternatives were dismissed and low-cost, low-impact alternatives were advanced for further consideration.

The evaluation criteria are listed in table 2-3.

The criteria were divided into three categories or "tiers" based upon their relative priority as indicators of the advantages or

constraints of each alternative. The following sections provide details of how each criterion was applied through the screening

process.

Table 2-3

Evaluation Criteria

Category Criteria

Primary

Criteria with positive or negative impacts. Important in

determining if the alternative is considered further.

• Expected annual "damage reduction" should not

exceed average annual costs

• Endangered species impacts

• Hazardous and Toxic Waste (HTW)

• Traffic safety

• Wetlands impacts

• Water quality impacts

Secondary

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Criteria whose impacts could be mitigated. Important

to the overall evaluation.

• Water quality impacts

• Cultural resources impacts/State Historic

Preservation Office (SHPO) requirements

• Lower Snake River Fish and Wildlife Compensation

Plan

Considered

Evaluated for direct, indirect, and cumulative impacts.

• Aquatic impacts (non-listed species)

• Terrestrial impacts

• Regional economic impacts

• Land uses

• Public opinion

• Other public interest factors

2.3.2.1 Expected Annual Damages

The estimated level of flood damage reduction provided by the alternatives for Lower Granite reservoir was analyzed based on the

elevations of the structures in the floodplain and on simulated water surface profiles for the alternatives. No distinction was made in

this preliminary screening between the flood damage reduction of the two dredged material disposal methods considered (e.g.,

in-water or upland disposal of dredged material).

The evaluation was based on the results of a risk-based, flood damage assessment computer model study. This flood damage

assessment considered the hydrologic statistical risk of floods, hydraulic variations in flood flow water surface elevations, and

associated damages to various types of buildings, structures, and activities in the floodplain.

2.3.2.2 Average Annual Costs

The present value of future costs for each alternative was calculated from the total costs of dredging, disposal of dredged material,

and construction of the proposed levee raises over the projected lives of the alternative scenarios and the estimated phasing of

construction, operation, and maintenance over that period. The alternatives were compared based on the present value of future

costs over a 74-year period computed at an interest rate of 6.875 percent. The interest rate used for discounting is the current

Department of the Interior rate to be used for Federal water resource planning purposes (63 FR 63329). Table 2-4 presents a

summary of average annual costs of plan measures.

Table 2-4

Average Annual Costs

Alternative

Annual

Alternative

Costs

No Action (No Change)

Maintenance Dredging $0.0

3-Foot (0.9-m) Levee Raise $152.0

4-Foot (1.2-m) Levee Raise $938.0

8-Foot (2.4-m) Levee Raise $2,595.0

12-Foot (3.7-m) Levee Raise $4,259.0

300,000 cy (229 366.5 m3) Dredge $1,233.0

1 Million cy (764 555 m3) Dredge $1,911.0

2 million cy (1 529 110m3) Dredge $4,706.0

2.3.2.3 Endangered Species

Listings of endange red species were obtained from the NMFS and U.S. Fish and Wildlife Service (USFWS). Habitat requirements,

timing of occurrence, and the potential location of listed species relative to the dredging and disposal sites were determined. A

potential impact determination was made based on the likelihood of ESA- listed individuals being present or if required habitat was

in the project vicinity. If no individuals were likely to be present or no habitat existed, a "no effect" determination was made. If habitat

was available, but because of timing of the project the species would not be present, a determination of "may affect but not likely to

adversely affect" was made. If habitat was available and individuals could be present, a determination of "may affect and likely to

adversely affect" was made. Biological Assessments (BAs) were prepared and sent to both the NMFS and USFWS. Copies of the

BAs along with documentation of consultation activities with NMFS and USFWS can be found in appendices F and G.

In the case of salmonids, certain in- water disposal alternatives have the potential for improving habitat conditions. In these cases,

the mitigation was assumed and a beneficial impact was determined to occur.

2.3.2.4 Hazardous, Toxic, and Radioactive Waste (HTRW)

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Impacts associated with HTRW materials were assumed if HTRW materials were present in the dredging template or disposal areas.

The potential presence of HTRW in sediments was a consideration for the in- water disposal sites and was determined by a review

of previous dredging experience and by review of the Corps’ sediment testing data. The presence of HTRW materials at the upland

disposal sites was determined from Phase 1 environmental site assessments that included interviews with the property owners,

searches of title records and environmental databases, and field inspections of the proposed disposal sites.

2.3.2.5 Traffic Safety

Impacts associated with traffic safety were evaluated for construction activities and for the transport of dredged material. Potential

impacts could occur from the additional traffic on existing roadways and from truck traffic crossing major roadways that would occur

under some of the alternatives. Therefore, the development of the conceptual designs for the upland disposal and transfer sites

took into account traffic safety. However, a further assessment of safety goes beyond the manageable traffic safety aspects of the

project and focuses on the longer term, unavoidable traffic safety issues. Where heavy, industrial-type activities (such as the

transfer and handling of large quantities of dredged material) would be located immediately adjacent to major highways and or

recreation facilities, the distraction was considered an unavoidable safety impact.

2.3.2.6 Wetlands

Wetlands were identified using spatial data provided through the National Wetlands Inventory (NWI), field reconnaissance, and

aerial photo interpretation. The NWI inventory was compiled from aerial photo interpretation and is not inclusive of all wetlands.

The proposed upland disposal and transfer sites and the Snake River shoreline adjacent to Asotin and Asotin Creek were visited to

evaluate impacts from the proposed upland storage and levee raise alternatives. Most of the alternatives involved minor indirect

effects on wetlands; however, the alternatives that proposed use of a transfer site for handling dredged material were determined to

have major impacts on wetlands.

2.3.2.7 Water Quality

The preliminary assessment of water quality impacts of alternatives was based on existing water quality data, previous Corps

environmental documentation, and consultation with Corps staff.

The following factors were used in evaluating potential water quality impacts of the alternatives:

Turbidity is the primary water quality criterion of concern.

Sediment quality could affect water quality and required consideration.

Monitoring and mitigation could reduce turbidity impacts to below significant levels.

Upland disposal and dewatering of dredged material would be unlikely to cause significant water quality impacts.

2.3.2.8 Cultural Resources

The cultural resources assessment is based on review of available literature and the resource files at the Washington Office of

Archaeology and Historic Preservation, the Idaho State Historic Preservation Office, and the Walla Walla District Corps of Engineers.

Information on cultural resources was gathered for proposed upland and in- water disposal areas and proposed dredging

templates. Preliminary evaluations of impacts to cultural resources were based on the presence of identified cultural properties that

a given alternative could potentially affect through activities such as dredging and disposal of dredged material.

2.3.2.9 Lower Snake River Fish and Wildlife Compensation Plan (LSRFWCP)

As part of the LSRFWCP, a terrestrial wildlife mitigation program was initiated to:

Protect existing habitat.

Provide high-quality upland habitat for a variety of wildlife.

Obtain additional land to fully compensate for upland game habitat losses that resulted from the construction of the lower

Snake River dams.

The plan called for the creation of a number of HMUs to accomplish these goals. The Joso site that was considered for upland

disposal of dredged material is managed as an HMU, and the Chief Timothy transfer site is adjacent to an HMU. Use of any of these

upland disposal sites would require avoiding adverse impacts to the HMUs, and mitigation of unavoidable adverse impacts.

Beneficial uses, such as woody riparian habitat development, would assist in meeting the compensation goals of the plan.

2.3.2.10 Aquatic Impacts on Non-Listed Species

Findings from previous Corps documents, a review of scientific literature, and first- hand knowledge by Corps and University of

Idaho biologists were considered to determine the presence or absence of non-listed species. As with the endangered species, an

analysis of habitat requirements, presence or absence of fish species, and the timing of migrations were evaluated to determine

potential impacts to resident fish. By disposing of materials near shore and building shallow water benches, certain in-water

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disposal alternatives would provide an opportunity to enhance habitat for resident fish species. In other cases, such as upland

disposal, the alternative would not impact aquatic species.

2.3.2.11 Terrestrial Impacts on Non-Listed Species

A Corps terrestrial ecologist determined the potential effects of alternatives on terrestrial wildlife habitat for non- listed species.

Proposed upland disposal involving the Chief Timothy and Page Creek sites was determined to have the greatest impact because of

the value of the habitat at Page Creek.

2.3.2.12 Regional Economic Impacts

Regional economic impacts are a measure of changes in personal income, sales, or value added expected in the region as a result

of each alternative. This criterion considers the impacts from navigation transportation and flood-related activities on employment

changes and shifts, and their effects on the regional economy. Each alternative would be expected to provide the same level of

navigation benefits and, therefore, no change in that sector of employment or business activity was considered. Each alternative

would produce a different flood damage reduction effort and a variety of different effects on jobs.

2.3.2.13 Land Use Impacts

The evaluation of potential land use effects of the alternatives was based primarily on the local property effects and the acquisition

requirements of each alternative. The focus of this evaluation was the developed/urbanized areas around Lewiston, Clarkston, and

Asotin, but also considered upland disposal impacts. While all levee alternatives would involve impacts to infrastructure and

recreation activities, none of the alternatives would cause substantial shifts in land use.

2.3.2.14 Public Perception

Public perception of each of the alternatives was qualitatively assessed based on the DMMS Public Scoping Meeting Summary

prepared by the Corps following two regional public meetings held in Richland, Washington, and Lewiston, Idaho, in September

1998. Public comments represented in the Scoping Meeting Summary were general in nature and did not address specific

dredging, levee modification, and disposal scenarios considered as part of this preliminary evaluation process. Comments received

on the Draft DMMP/EIS were considered and are attached as Appendix O.

2.4 MEASURES REMOVED FROM FURTHER CONSIDERATION

Following preliminary screening, a distinction emerged between those measures that most efficiently met the purpose and need and

those measures that had high environmental and economic impacts. Through this screening process, alternatives that were

infeasible and/or had potentially high costs and environmental impacts in comparison to other measures could be removed from

further consideration.

Table 2-5 summarizes the measures that were removed from further consideration.

Table 2-5

Measures Removed From Further Consideration In This EIS

Measures Reason(s) Removed From Further Consideration

Change Upstream Land Uses Not a complete solution to maintain navigation; initial authority

and resources development.

Reservoir Drawdown Does not meet flow conveyance purpose and need, particularly

navigation.

In-Water Sediment Control Not practical or feasible for the entire project.

Dredging Up to 2 Million Cubic Yards (1 529 110 m3) With

Upland Disposal

High adverse environmental impacts; high cost; beyond scope

of action required to address purpose and need.

Dredging Between 300,000 and 2 Million Cubic Yards Per Year

(229 367 to 1 529 110 m3)

Scope of action not required or feasible to meet flow

conveyance.

Construct Upstream Sediment Traps Prohibited by PL 100-677; potential impact to Wild and Scenic

River.

Levee Modification - Raising Levees 4, 8, or 12 Feet

(1.2, 2.4, or 3.7 m)

Scope of action not required or feasible to meet flow

conveyance.

The measures that were advanced for further consideration are presented in the following section.

2.5 ALTERNATIVES SELECTED FOR FURTHER CONSIDERATION

Following a process of defining the purpose and need for the programmatic DMMP/EIS and developing a broad range of plan

measures, the Corps conducted a screening of those measures, considering environmental, technical, and economic factors. From

those measures, alternatives that are reasonable and fulfill the requirements of the purpose and need were formulated. These

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alternatives are subject to detailed environmental and socioeconomic review (presented in sections 3 and 4 of this DMMP/EIS); from

this set of alternatives, a preferred alternative was selected.

This section presents the alternatives that have been formulated from plan measures that passed the screening process and are

evaluated in this DMMP/EIS. In addition, this section presents the "No Action" alternative, which provides a baseline for comparison,

and is required by NEPA.

For the purposes of this DMMP/EIS, the “No Action” alternative is defined as no change and referred to as the "No Action (No

Change)" alternative. The "No Action (No Change)" alternative includes the Corps’ anticipated program of continued maintenance

dredging in the lower Snake River and McNary reservoirs. This maintenance program includes dredging the navigation channels

and other related facilities (ports, moorages, recreation areas, and irrigation intakes), and providing some restoration of flow

conveyance at the confluence area of the Lower Granite reservoir. Selection of "No Change" is consistent with the Council on

Environmental Quality’s guidance in NEPA’s Forty Most Asked Questions which states that where ". . . on-going programs initiated

under existing legislation or regulations will continue, even as new plans are developed.... ‘no action’ is ‘no change’ from current

management direction or level of management intensity." (46 Federal Register 18026, as amended, 51 Federal Register 15618).

Table 2-6 provides a summary comparison of the alternatives and sections 2.5.1 through 2.5.4 provided detailed descriptions of the

alternatives.

Table 2-6

Comparison of Alternatives

Alternative

Dredging

Requirement

Dredged

Material

Disposal

Annual

Dredging

Costs

Levee

Modification

Relocation/

Acquisition

Requirements

1 - No Action (No Change) -

Maintenance Dredging With In-Water

Disposal

Maintenance1

In-Water, primarily to

create shallow water

fish habitat

$560,000 None None

2 - Maintenance Dredging With

Beneficial In-Water Disposal and a

3-Foot (0.9-m) Levee Raise

Maintenance1

In-Water to Create

Shallow Water

Fishery Habitat

$560,000

Raise levees up to 3 feet

(0.9 m) to maintain flow

conveyance capacity

Limited raising

of roadways

3 - Maintenance Dredging With

Upland Disposal and a 3-Foot (0.9-m)

Levee Raise

Maintenance1

Upland at "Joso" site

in Lower Monumental

Reservoir

$730,000

Raise levees up to 3 feet

(0.9 m) to maintain flow

conveyance capacity

Limited raising

of roadways

4 - Maintenance Dredging With

Beneficial Use of Dredged Material

and a 3-Foot Levee Raise

Maintenance1Beneficial Use $560,0002

Raise levees up to 3 feet

(0.9 m) to maintain flow

conveyance capacity

Limited raising

of roadways

Note:

1Includes maintenance of the authorized navigation channels of the lower Snake River reservoirs and McNary reservoir; maintenance dredging of access channels to port and moorages on an as-needed basis, public

recreation areas (swimming beaches and boat basins), irrigation intakes for wildlife HMU's managed by the Corps; and flow conveyance capacity of the Lower Granite reservoir.

2Beneficial use see Section 2.5.4.2.

2.5.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

2.5.1.1 General Description

This alternative considers those activities (mechanical dredging and in- water disposal) that have been performed in the recent past

to maintain the aut horized depths in the navigation channels of the lower Snake River dams and McNary navigation project. The

areas covered include Lake Wallula behind McNary on the Columbia River and the reservoirs behind the four lock and dam projects

on the lower Snake River: Ice Harbor, Lower Monumental, Little Goose, and Lower Granite. This navigation project provides for a

14-foot (4.3-m) channel with at least 14 feet (4.3 m) over the sills at each of the locks and 14-foot (4.3-m) by 250-foot (76.2-m)

channels providing access to port and barge loading facilities in each reservoir. Sediment has been deposited over time, reducing

the navigation clearances in places in each reservoir and the flow conveyance capacity of the upper reservoir behind Lower Granite.

This alternative would provide navigation clearance and provide some restoration of the flow conveyance capacity based upon

maintenance dredging.

Additionally, maintenance dredging of access channels to ports and moorages occurs infrequently, on an as-needed basis. The

Corps also periodically conducts maintenance dredging around public recreation areas, such as swimming beaches and boat

basins, and irrigation intakes for wildlife HMU's managed by the Corps.

2.5.1.2 Dredging Areas and Quantities

Maintenance dredging is a project component to maintain navigation clearances in each of the five reservoirs and maintain flow

conveyance of the Lower Granite reservoir. Dredging templates were designed for each reservoir to achieve the maintenance

dredging requirements. For the Lower Granite reservoir, the areas that require dredging for navigation are located on the Clearwater

River between the Snake River confluence and the Port of Lewiston, located between Clearwater RM's 0.00 and 1.56, and on the

Snake River from the vicinity of Silcott Island near Snake RM 131 upstream to the U.S. Highway 12 bridge located near Snake RM

139.5. A range of dredging volumes between 16,000 and 300,000 cy (12 232.9 and 229 367 m3) are required on a 2-year cycle to

develop and maintain the designed navigation channels in the Lower Granite reservoir. An estimated 4,000 cy (3 058 m3) are to be

dredged from behind Little Goose, and 2,000 cy (1 529 m3) from behind Lower Monumental and Ice Harbor dams at 2- year

intervals. The areas to be dredged in each case are located at the upstream end of each reservoir. The maintenance dredging for

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the McNary reservoir is estimated to be approximately 32,000 cy (24 466 m3) every 2 years. The maintenance dredging and disposal

areas for each of the five reservoirs are identified on the plates.

2.5.1.3 Dredging Template Design

The navigation dredging template is 250 feet (76.2 m) wide, with dredging to provide a channel depth of 14 feet (4.3 m) below the

minimum authorized pool elevation of 733 feet msl at Lower Granite, 633 feet msl at Little Goose, 537 feet msl at Lower

Monumental, 437 feet msl at Ice Harbor, and 335 feet msl at McNary. The dredging template for other maintenance activities would

vary, but includes access to port and moorage facilities, public recreation areas, and irrigation intakes.

2.5.1.4 Dredging Program and Process

Dredging would be accomplished mechanically, probably using a clamshell with an approximate 15-cy (11.5-m3) capacity

discharging to a barge with a capacity of 3,000 cy (2 293.7 m3). The barges would have a maximum size of 240 feet (73.2 m) long by

42 feet (12.8 m) wide with a maximum draft of 14 feet (4.3 m). The expected rate of dredging is 5,000 cy (3 822.8 m3) per 8-hour

shift. Dredging would be performed in the Snake River during the period of December 15 through March 1 and for a longer period

from December 1 to March 31 in the Columbia River. Multiple shift dredging workdays would be used when necessary to ensure

that dredging was completed within these windows.

All material dredged in the Lower Granite reservoir would be disposed of downstream of Centennial Island, located near Snake RM

120.46. The entire channel below elevation 670 feet msl is available to be used for material disposal as required. Sands, gravels,

and cobbles, expected to comprise 85 percent of the total material, would be dumped in the shallow to mid-range depths from 15 to

60 feet (4.6 to 18.3 m) to form shallow water habitat. Approximately 15,000 cy (11 468.3 m3) of dredged material would be deposited

per acre. The remaining 15 percent of material that is silt or finer would be deposited in deep water. This alternative would use only

a small portion of the total volume of dredged material available for deposition. The total disposal volume available for the entire

disposal area based on a level horizontal surface at elevation 670 feet msl was computed from a 1997 survey as approximately 120

million cy (91 746 600 m3).

The 4,000 cy (3 058 m3) of dredged material originating from behind Little Goose reservoir and 2,000 cy (1 529 m3) of material from

Lower Monumental and Ice Harbor reservoirs at 2-year intervals would be disposed of at in- water sites immediately upstream of the

respective dams. The 32,000 cy (24 466 m3) of material removed from the McNary reservoir at 2-year intervals would be disposed of

at in-water sites near the confluence of the Columbia and Snake Rivers to form improved fish habitat and in deep-water sites

downstream of the Walla Walla River (plates 3 and 4).

2.5.1.5 Material Types

Dredged materials would be comprised mostly of sediments containing a mixture of silts, sands, gravels, and cobbles carried by

inflowing waters as suspended and bedload material. Based on previous experience, 85 percent of the material is expected to be

sands, gravels, and cobbles, and 15 percent of the material is expected to be silts and finer-grained material. Small amounts of

material unsuitable for in-water disposal may require disposal at an upland site.

2.5.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

2.5.2.1 General Description

This alternative considers the same dredging activities as alternative 1, "Maintenance Dredging" or "No Action (No Change)," but

with changes in dredging methods, work window, and disposal location for silt. Mechanical dredging would still be the primary

dredging method used, but hydraulic dredging would also be considered for off-channel areas on a case-by-case basis. The

majority of the dredging would be done during the winter in-water work windows used in the "No Action (No Change)" alternative,

but a summer work window, possibly August, would be considered for off-channel areas on a case-by-case basis. All summer

dredging would use upland disposal of the dredged material. The disposal method for winter dredging is formalized to include

in-water disposal of most of the dredged material to create shallow water fish habitat. Silt would no longer be disposed of in

deep-water sites. The areas dredged for channel maintenance remain the same and include Lake Wallula behind McNary on the

Columbia River and the reservoirs behind Ice Harbor, Lower Monumental, Little Goose, and Lower Granite on the lower Snake River.

Additionally, maintenance dredging of access channels to ports and moorages occurs infrequently, on an as-needed basis. The

Corps would continue to periodically conduct maintenance dredging around public recreation areas, such as swimming beaches

and boat basins, and irrigation intakes for wildlife HMU's managed by the Corps.

The disposal sites for this alternative would likely differ from alternative 1. The Corps evaluated all five reservoirs for potential sites

suitable for in-water disposal. Sites were restricted to areas in the lower ends of each reservoir to eliminate the potential to

negatively affect water surface levels at the upper end of each reservoir. For several reasons, the Corps concentrated its evaluation

of sites on Lower Granite reservoir. One is that it is the uppermost reservoir and juvenile salmonids found in that reservoir would

benefit more from additional rearing areas and associated increased growth potential. Another reason is that there are no collection

and transport facilities above Lower Granite; therefore, more juveniles use Lower Granite reservoir than the other reservoirs. Finally,

most of the dredging would occur in Lower Granite reservoir; therefore, it would be more cost-effective to dispose of the material

within the reservoir. However, in-water disposal to create shallow-water habitat in other reservoirs would be considered depending

upon the location of the dredging area, the type of material to be dredged, and the quantity to be dredged.

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The Corps identified seven potential sites in Lower Granite reservoir suitable for shallow water rearing habitat creation (figure 2-6).

The sites were identified because they are on the inside of a river bend, have suitable water velocities and underwater contours to

facilitate habitat creation, and they are configured so the dredged material can be deposited without burying known cultural

resource sites.

Alternative 2 would employ an "adaptive management" approach to the overall implementation of the DMMP. The Local Sediment

Management Group (LSMG) (see Section 1.8) would provide input and feedback to the Corps with respect to dredging and dredged

material management that would be implemented under this alternative, as well as Alternatives 3 and 4.

The adaptive management approach would allow the Corps and the LSMG to regularly evaluate dredging and dredged material

management activities and monitoring results, and make needed adjustments to the overall course of action.

A levee raise of up to 3 feet (0.9 m) at critical locations is added to this alternative to maintain the flow conveyance capacity of the

upper reservoir behind Lower Granite at the confluence of the Snake and Clearwater Rivers.

2.5.2.2 Disposal Process

The disposal process is dependent on the physical characteristics of the material and the potential to optimize the benefit to fish.

Sediment samples would be taken from the areas to be dredged and would be evaluated for particle size, contaminant levels, and

suitability for in- water disposal. Particle size analysis would identify which dredging sites or portions of sites contain mostly silt and

which ones contain mostly sand or coarser material.

The sequence of dredged material disposal for the majority of the dredging activities is designed to accomplish two goals: (1) create

shallow-water habitat for juvenile salmon, and (2) dispose of silt in a beneficial manner. To meet these goals, the dredged material

would be placed in steps. The first step would be to use the silt [less than .008 inch (0.2 mm) in diameter] in a mixture with sand

and gravel/cobble to fill the mid-depth portion of a site and form a base embankment. The dredged material would be placed

aboard bottom-dump barges and analyzed to determine the percentage sand or silt to ensure the mixture in the embankment was

not more than 30 percent silt. The barges would then proceed to the disposal area and would dump the material within the

designated footprint close to the shoreline to raise the river bottom to create an underwater shelf about 10 feet (3 m) below the

desired final grade. The second step would be to place sand on top of the sand/silt embankment. An area of sand would be

reserved as the final area to be dredged during that dredging activity. Barges would be used to dump the sand on top of the base

embankment in sufficient quantity to ensure that a layer of sand at least 10 feet (3 m) thick covers the embankment once the final

step of the process is completed. The footprint of the disposal area would be sized so that the maximum amount of shallow water

habitat is created with the estimated quantities of material to be dredged during that dredging activity. The final step would be to

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use a beam drag to flatten and level the tops of the mounds to form a flat, gently sloping (3 to 5 percent) shallow area with water

depths up to 20 feet (6.1 m) as measured at minimum operating pool level. The sand cap layer would be created with a minimum

thickness of 10 feet (3 m) to ensure the most desirable substrate (sandy with limited fine- grained or silt material) is provided for

salmonid rearing habitat.

To determine the minimum surface acreage of habitats to be created, pre-impoundment aerial photos of the shorelines of the lower

Snake River were studied and the sandy, shallow water areas conducive to rearing fall chinook were measured. Historically, a wide

size range of these habitats existed but a minimum surface area for shallow water habitat creation was designated as 4 acres (1.6

hectares). This acreage was actually lower than the average habitat area found pre-impoundment but was calculated as the

minimum necessary to attempt to mimic the free-flowing shoreline habitat required by fall chinook salmon.

On a case-by-case basis, hydraulic dredging may be considered for off- channel areas such as irrigation intakes. This would

probably be done in the summer when salmonid fish are less likely to be found in these shallow water areas because of elevated

water temperatures. To minimize turbidity, the hydraulic dredging would be limited to methods that do not agitate the sediments.

The dredged material would exit the dredge as a slurry that is likely to be 65 to 80 percent water and would not be suitable for

in-water disposal as described above. Instead, this slurry could be incorporated into the wildlife habitat planting areas or used to

restore eroded streambanks near the intakes.

Summer dredging may also be considered for other off-channel areas such as swim beaches or boat basins on a case-by-case

basis. These shallow-water areas wo uld be expected to have elevated water temperatures during the summer and would not likely

have salmonid fish present. The material dredged from these sites would probably be disposed of at an upland location since the

in-water disposal areas are located in the main river channel and may have salmonid fish present during the disposal activity.

Table 2-7 compares the dredging options of timing, method, and disposal location for the various areas that would be dredged

under this DMMP/EIS.

Table 2-7

Dredging Options By Area

Reservoir

Dredging Option*

Time of Year

To Dredge

Method of

Dredging

Disposal

Locations

Navigation Channel Winter Mechanical In-water or upland

Ports Winter Mechanical In-water or upland

Boat Basins

Winter Mechanical In-water or upland

Summer Mechanical or hydraulic Upland

Swim Beach

Summer Mechanical or hydraulic Upland

Winter Mechanical or hydraulic In-water or upland

Irrigation Intakes

Summer Mechanical or hydraulic Upland

Winter Mechanical or hydraulic In-water or upland

*Options listed in order of preference

A contingency upland disposal site has been identified to provide storage for dredged material that may, for whatever reason, need

to be deposited on a separate upland site. In the event that dredged material may be unsuitable for beneficial use or disposal inwater, it would be isolated at the Joso upland disposal site (RM 56.5 and RM 58.6) and appropriate confinement measures would be

taken to isolate this material (e.g., installing an impervious liner to prevent leaching of contaminated materials).

2.5.2.3 Levee Raise

Sediment accumulation in the Lower Granite reservoir continues to reduce the level of protection provided by the levees at Lewiston,

Idaho. The proposed levee raise would result in the following:

Levees: The west Lewiston levee would be raised as much as 3 feet (0.9 m) in some locations. However, on the whole, most levee

raises would be less than 3 feet (0.9 m).

Highways/Roads: Highway 129 downstream of Asotin and the Snake River Road upstream of Asotin would be raised.

Recreation Areas: The plan calls for cleanup of Hellsgate State Park, Swallows Park, and the Corps Clarkston office, boat ramp,

and restrooms in the event of a flood.

Commercial Buildings: The plan would increase in the risk of flooding one commercial building, a U.S. Forest Service building, and

a Corps building. The levee raise would not affect utilities, bridges, railroad tracks, or private homes.

2.5.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

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2.5.3.1 General Description

This alternative considers the same dredging activities as alternatives 1 and 2, but with upland disposal of all dredged material and

no in-water disposal. The 3-foot (0.9- m) levee raise described as a part of alternative 2 would be included with this alternative (see

section 2.5.2.3). The areas dredged for channel maintenance in this alternative remain the same and include Lake Wallula behind

McNary on the Columbia River and the reservoirs behind Ice Harbor, Lower Monumental, Little Goose, and Lower Granite on the

lower Snake River. This alternative would continue to maintain the navigation clearances in each reservoir and maintain the flow

conveyance capacity of the upper reservoir behind Lower Granite. Additionally, maintenance dredging of access channels to ports

and moorages occurs infrequently, on an as- needed basis. The Corps would continue to periodically conduct maintenance

dredging around public recreation areas, such as swimming beaches and boat basins, and irrigation intakes for wildlife HMU's

managed by the Corps. This alternative would ensure navigation clearance and maintain the flow conveyance by raising levees that

protect Lewiston, Idaho, as in alternative 2. Under this alternative, dredged materials would be transported by barge to the Joso

upland disposal site.

2.5.3.2 Upland Disposal Site

The location for upland disposal of dredged material would be the Joso site on the Snake River below Little Goose on the sout h

bank at RM 56.5 to RM 58.6 (plate 11). The site is located at a bend in the river and is bounded on the southern side by the Union

Pacific Railroad, giving it a roughly triangular shape. The entire site is approximately 568 acres (229.9 hectares), with open

space/habitat management being the present use. Barge access to the Joso site would be at the west end providing access to a

disposal area of approximately 280 acres (113.3 hectares) located in the center of the site with 600-foot (182.9-m) buffers from the

river. Initially, the disposal area would be confined to a disturbed site that was historically used for gravel extraction and currently

contains an exposed open gravel pit.

Use of the Joso site would require reconstruction of some facilities and construction of others. The existing barge slip would need to

be dredged to restore access. The barge slip would also be reconstructed using anchored sheet pile to provide vertical walls and tie

off facilities. Temporary dredged material dewatering and storage areas with containment berms and detention ponds would be

constructed adjacent to the slip. The material would be off-loaded from the barges and placed in the temporary storage for

dewatering, then would be loaded onto trucks for transport to the disposal area. The material would then be placed in lifts using

track-type tractors and compacted, resulting in a large structural fill conforming to the established final topography for the disposal

area. Areas that reach final grades would be restored on a periodic basis by placing 6 inches (15.2 cm) of topsoil and re-seeding

with native grasses to achieve a vegetative cover similar to the surrounding site areas. Filling the gravel pit with sediment and

seeding it to grass would improve the site’s va lue as wildlife habitat. Contaminated or unsuitable dredged materials would be

isolated and appropriate confinement measures taken (e.g., an impervious liner installed to prevent leaching).

2.5.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and

a 3-Foot (0.9-m) Levee Raise

2.5.4.1 General Description

This alternative considers the same dredging activities as alternatives 1, 2, and 3 with mechanical dredging as the primary dredging

method. Hydraulic dredging would be considered on a case-by-case basis for off-channel irrigation intakes only. The areas dredged

for channel maintenance remain the same and include Lake Wallula behind McNary on the Columbia River and the reservoirs

behind Ice Harbor, Lower Monumental, Little Goose, and Lower Granite on the lower Snake River. Additionally, maintenance

dredging of access channels to ports and moorages occurs infrequently, on an as- needed basis. The Corps would continue to

periodically conduct maintenance dredging around public recreation areas, such as swimming beaches and boat basins, and

irrigation intakes for wildlife HMUs and recreation sites managed by the Corps.

As with alternatives 2 and 3, a levee raise of up to 3 feet (0.9 m) at critical locations is added to this alternative to maintain the flow

conveyance capacity of the upper reservoir behind Lower Granite at the confluence of the Snake and Clearwater Rivers (see 2.5.2.3).

2.5.4.2 Beneficial Uses

The management strategy for dredged material under this alternative would be beneficial use. Beneficial uses could include

creation of shallow-water fish habitat, creation of riparian habitat, fill material for construction, etc. For each dredging activity, the

Corps would identify potential beneficial uses and coordinate the uses with the LSMG prior to selecting a use. Beneficial uses, as

defined by this process, may be achieved when a local sponsor is willing to contribute a share of the cost. Potential beneficial uses

that have been identified to date include:

2.5.4.2.1 Fish Habitat Creation

Fish habitat creation would be the same disposal method used in alternative 2, "Maintenance Dredging With Beneficial In-Water

Disposal and a 3-Foot (0.9-m) Levee Raise." This method is described in section 2.5.2.2. This beneficial use would result in the

creation of shallow-water fish habitat to benefit juvenile salmonid fish.

2.5.4.2.2 Woody Riparian Habitat Program

The Corps has proposed the "woody riparian" program to help meet the goals of the Lower Snake River Fish and Wildlife

Compensation Plan within the state of Washington. The woody riparian program would create and enhance riparian habitats along

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the lower Snake River.

The Lower Snake River Fish and Wildlife Compensation Plan (LSRFWCP) was drafted in 1975 to provide direction and funding for

environmental mitigation as a result of the construction of lower Snake River lock and dam projects. The LSRFWCP was divided into

components to address anadromous fish, resident fish, and terrestrial wildlife. The woody riparian program has been developed to

address the LSRFWCP’s specific goals for terrestrial wildlife mitigation.

Initially, the Corps proposes to implement the woody riparian program in Lower Granite Reservoir near the Chief Timothy Habitat

Management Unit. Proposed woody riparian habitat creation would consist of developing a shallow, sloping bench (approximately

two feet below surface at the maximum operating pool), extending along approximately 3,000 linear feet of shoreline between RM

131.6 and 133.4. The Corps has identified this particular site because it has a high potential for successful woody riparian habitat

development, would not interfere with navigation, would not impact known cultural resources, and would be close to the

Snake/Clearwater River confluence where most dredging is proposed to occur. Dredged material placed in this proposed area

would accomplish three goals consistent with the LSRFWCP:

Create planting zones for woody riparian habitat;

Increase suitability and acreage of shallow water rearing habitat for Snake River fall chinook juveniles; and

Provide a beneficial use of dredged material.

The Corps proposes to use dredged material from planned 2002-2003 dredging to develop woody riparian areas as described

above. Details of proposed woody riparian habitat development are provided in Appendix N.

2.5.4.2.3 Hanford Site Capping

The Richland Office of the U.S. Department of Energy (USDOE) has responsibility for management of the nearby Hanford site (plate

7). The 570-square-mile (1 476.3-square-km) Hanford Site was founded early in World War II to produce plutonium for the nation’s

first atomic weapons. Since the mid-1950's, the mission of Hanford has broadened to meet energy and defense needs. One of the

many uses of the Hanford site has been the storage of contaminated wastes including commercial, low- level radioactive waste

received from hospitals, research facilities, industries, and nuclear power stations. Treatment and storage of these contaminated

wastes often involves the use of clean soils as a capping material. While the quantities of material required for capping of burial

sites on the Hanford site have yet to be determined, Comprehensive Environmental Response Compensation Liability Act (CERCLA)

of 1980 and Resource Conservation and Recovery Act (RCRA) compliance indicates that there could be requirements for large

volumes of materials including: fine-grained clays and silts, fine to coarse gravel, cobbles, and larger stone or riprap material. The

quality of materia ls imported onto the Hanford site is of concern and all such materials must be sampled to identify constituents

and/or contaminants. The USDOE is in the process of evaluating sources of fill for uses on the Hanford site. The USDOE will be

addressing issues such as availability of off-site materials, the impact of utilizing on-site borrow material, site restoration

requirements, and the anticipated volume of materials required in the near future (USDOE, 1999).

Dredged material would provide an excellent source of clean material for this use. Dredged material from channel maintenance

dredging in McNary reservoir (Lake Wallula) could be used by barging these materials an additional 10 miles (16.1 km) and offloading them at facilities owned by the Port of Benton adjacent to the Hanford site. Costs for this beneficial use would be

determined by the added cost to transport the material to the off-load and temporary storage facilities. The added maintenance

dredging costs for this additional 10 miles (16.1 km) of barge transport and off- loading would be borne by the USDOE. Storage at

the temporary site and transportation of the material to the use location would be the responsibility of the USDOE.

2.5.4.2.4 Potting Soil

Dredged material removed from the Lo wer Granite reservoir has constituents that make it excellent as a potting soil or soil

enhancer. The Port of Whitman County has investigated a system that processes straw, digestible solid waste, and soil (dredged

material as proposed in this alternative) in a continuous digester to produce a final product that is used as potting soil, top dressing

for turf areas such as golf courses and parks, or to enhance production of agricultural crops. Straw, a surplus commodity from the

highly productive Palouse Hills grain growing area adjacent to the Port of Wilma, is an ideal raw material for this process. Solid

waste from the Lewiston-Clarkston-Pullman-Moscow metropolitan areas can be classified to remove recyclable materials and other

unsuitable materials that might make it unusable as a raw material for this digestive process. Dredged materials from Lower Granite

reservoir would supply the third raw material for this process. The net result would be to convert straw, solid waste, and dredged

materials into a marketable commodity. This would create a new industry for this region of Washington and Idaho with resultant

gains in employment and spendable income. The Port of Whitman County has proposed packaging this material for sale in the

region. Their plans call for up to 300,000 cy (229 367 m3) per year of dredged material to be delivered by barge to a temporary

holding site at the Port of Wilma. The additional cost of this activity would be paid by the Port of Whitman County.

2.5.4.2.5 Riparian Habitat Restoration

Dredged material has been used to construct riparian habitat in this reach of the Columbia/Snake River system, similar to that

described in section 2.5.4.2.2 above. Where additional opportunities exist to barge and off- load material to cover riprap, to create

islands or to build sub-impoundment areas, local sponsors may contract with the Corps to construct these projects on a one-time

basis. The added cost of dredging maintenance required to use the dredged material to restore the environment would be

cost-shared 25 percent by a local sponsor and 75 percent by the Federal government. Section 204 of the Water Resources

Development Act of 1992 provides the authority for this cost sharing, provided that the local sponsor provides all lands, easements,

rights-of-way, and relocations necessary, and owns and operates the finished project. The following projects and sponsors were

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tentatively identified as potential beneficial uses of dredged material to restore the ecosystems on existing levees:

Levee 2C - City of Richland: Create shallow shoreline areas by filling over existing steep slopes.

Levee 4A - City of Richland: Create shallow backwater near the Yakima River confluence.

Levee 12-1 - City of Pasco: Fill at the toe of the existing levee creating a gentle shelf to 15-foot (4.6-m) water depth.

Levee 12-2 - Franklin County: Create a gently sloping shallow-water area to 15 feet (4.6 m) deep.

Levee 5D - City of Kennewick: Fill from Clover Island to Blue Bridge at a slope of 7 feet horizontal to 1 foot vertical (7:1).

Clover Island - Port of Kennewick: Fill from east end of the island to the Cable Bridge at a slope of 7:1 and fill from the west

end of the island to create a flat shallow extending to a berm angling at 30 degrees from the levee.

Levee 6B - Benton County: Fill along the shore downstream of the Cable Bridge to produce flat shallows.

East of Two Rivers Park and Levee 15D - Benton County: Fill near shore areas to create flat shallow fish habitat.

2.5.4.2.6 Port of Wilma Fill

The Port of Wilma has long-term plans to fill the empty dredged material disposal cells previously formed west of and adjacent to

the currently developed port facilities. This potential dredged material disposal area currently has the capacity to accommodate

approximately 370,000 cy (282 885.3 m 3 ) of dredged materials in Cell #2 and 100,000 cy (76 455.5 m3) in Cell #3. Access to this

site for future disposal of dredged materials is currently hampered by near-shore shallow waters designated as critical habitat for

listed juvenile fall chinook salmon and potential cultural resource impacts.

Access for unloading of dredged materials appears to be available at two locations adjacent to these potential dredged material

disposal sites. Barge access is currently available at the west end of the developed area at the Port of Wilma (e.g., land leased by

Tidewater Barge Lines for the purpose of constructing and launching barges). It may be possible to off- load dredged material from

barges at this site and to stockpile these dredged materials on site. These stockpiled dredged materials could then be transferred

across a previously filled and currently undeveloped dredged material disposal cell to currently available dredged fill disposal areas.

These materials could be transferred hydraulically using pumps and pipelines or mechanically by using earthmoving equipment.

A second potential site for off- loading dredged material from barges exists approximately 3,000 feet (914.4 m) downstream from the

west end of the Port of Wilma developed area. This is an area, offshore from the potential disposal area, approximately 700 feet

(213.4 m) long by 150 feet (45.7 m) wide that is filled to an elevation of 740 feet msl. This appears to be downstream of juvenile

salmonid habitat areas and appears to have sufficient water depth adjacent to the riverside face to accommodate loaded barges.

Dredged material could be moved via a causeway some 500 to 600 feet (152.4 to 182.9 m) shoreward to the disposal area by

conveyor or earthmovers for placement in the potential disposal area.

The increased cost of transport and off-load of the dredged material would be borne by the Port of Wilma.

2.5.4.2.7 Fill of Non-Federal Public Land

Non-Federal requests for beneficial use of dredged material to fill land may be allowed, provided additional implementation costs

are non-Federal and no additional cost would accrue to the Federal project. The non-Federal cost share shall be the difference

between the base plan presented in this document and the cost of delivering the dredged material to meet the non-Federal

sponsor’s beneficial use.

2.5.4.2.8 Lower Granite State Route (SR) 193/SR 194 Road Connection

The Port of Whitman County has promoted the construction of a section of roadway along the north shore of the Lower Granite

reservoir linking SR 193 at Wawawai to SR 194 at Lower Granite. A new 3-mile (4.8-km) section of roadway at this location would

eliminate use of a 32-mile (51.5-km) stretch of steep, narrow roadway via SR 193 and SR 194 to access Lower Granite from the Port

of Whitman County’s Port of Wilma facility near Lewiston and Clarkston. The proposal is to use dredged material to construct a

structural berm in Lower Granite reservoir on which this 3.5-mile (5.6-km) roadway would be constructed. This berm would be

constructed in conjunction with placement of additional dredged materials between the shoreline and the structural berm to create a

shallow-water habitat, along the north shore of this deeper part of Lower Granite reservoir, to facilitate downstream migration of

juvenile salmon and steelhead. A Feasibility Study entitled "Construction of Road from Lower Granite to Wawawai Canyon, Whitman

County, Washington," dated September 1981, prepared by the Walla Walla District, U.S. Army Corps of Engineers presented nine

alternative routes for construction of this road.

There are numerous benefits associated with this alternative. The Whitman County Sheriff’s Department has documented that

construction of this 3.5-mile (5.6-km) road segment would eliminate the current 45-mile (72.4-km) drive from Wawawai to Boyer Park

near Lower Granite. They cite emergency response times, icy winter driving conditions and heavy usage of both Wawawai and

Boyer Parks by university students as safety issues that justify the construction of this road segment. Recreational benefits,

presented by the Whitman County Parks and Recreation Department, include increased recreational usage of both Boyer Park and

Wawawai Park; increased access to the Snake River (Lower Granite reservoir); and completion of recreational facilities for the Lower

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Clarkston area and from grain growing areas closer to Almota. Travel distance from the Lewiston-Clarkston area to

government-owned and -operated facilities at Lower Granite would also be reduced.

Examination of preliminary roadway sections developed during the 1981 Corps study indicates that significant quantities of dredged

materials could be incorporated into construction for one of the proposed routes. The initial route involves construction of this

roadway upon fill placed adjacent to and on the riverward side of the existing railroad tracks. It is estimated that this route could

accommodate 500,000 cy (382 277.4 m3) of dredged materials. The Corps estimated the total cost of constructing this route at $14.8

million in 1981. Allowing a 30 percent cost escalation for inflation, the present day construction cost for this route would be

approximately $20 million.

The 1981 Corps study had identified the least expensive route as constructing a roadway on the landward side of the railroad tracks

and involved mostly excavation into the steep terrain adjacent to the railroad. The estimated costs for the least expensive route were

estimated at $6.71 million in 1981. The Corps identified another route as the preferred route. This route was generally constructed

on the landward side of and parallel to the existing railroad tracks; however, it involved three railroad crossings and approximately

6,000 feet (1 828.8 m) of roadway in or adjacent to Lower Granite reservoir. It is estimated that this route could accommodate

approximately 200,000 cy (152 911 m3) of dredged materials. In 1981, the Corps estimated construction costs for the preferred route

at $7.87 million. Allowing a 30 percent cost escalation for inflation, the present day cost would be approximately $10.25 million.

Comparing the beneficial use for these two roadway routes to the proposed in-water dredged materials disposal alternative results

in an additional cost for disposal. Construction of the various routes considered would utilize some 500,000 cy (382 277.4 m3) of

dredged materials. Construction of the preferred route would utilize some 200,000 cy (152 911 m3).

Utilization of dredged materials is subject to determining a satisfactory means of placing the dredged materials, the structural

suitability of these dredged materials, and environmental considerations. Use of dredged materials for roadway embankment could

significantly reduce the overall cost of construction for either the initial route or the preferred route as proposed by the Corps in the

1981 study.

2.5.4.2.9 Research of Beneficial Uses

Two research groups at the Corps of Engineers Waterways Experiment Station (WES) in Vicksburg, Mississippi, are investigating

measures to use this type of material. One group may be interested in determining economic and biological values to be obtained

from the use of the material in the riparian environment. The other group may be interested in demonstrating the application of this

material as a top dressing composed of sewage sludge, dredged material, and other ingredients. Dredged material removed from

the Port of Walla Walla barge channel at Boise Cascade is expected to be predominantly fine grain sediment suitable for use as a

top dressing and habitat restoration. There are various locations within proximity to the Boise Cascade channel that provide the

opportunity including sites in The Dalles reservoir (The Cliffs), John Day reservoir (Goodnoe, Plymouth), and McNary reservoir

(Hood Park and the various Shot Rock Islands). The LSMG may look for opportunities to participate with the WES research groups

to implement these research efforts.

2.6 MITIGATION

The environmental effects of the alternatives are discussed in detail in section 4. In general, none of the alternatives under

consideration are expected to result in significant environmental impacts. Mitigation strategies have been developed to address the

environmental impacts that are expected to result from the alternatives. These strategies are also discussed in section 4.

A prominent programmatic mitigation measure that is relevant to dredging and disposal of dredged material is the creation of woody

riparian habitat and shallow-water habitat with the dredged material. Implementation of this mitigation measure would compensate

for effects of dredging and disposal activities on aquatic resources, and in particular, endangered salmonid species. The Corps

would conduct long-term monitoring of shallow-water disposal sites to evaluate the success and quality of habitat creation.

Mitigation is also proposed for direct and indirect impacts due to dredging, disposal (both upland and in-water), and construction

activities related to proposed levee height modifications. In general, mitigation strategies include:

Avoiding impacts through timing of specific activities or location of upland disposal facilities and construction activities.

Sampling and analyzing sediments prior to dredging following criteria in the Dredged Material Evaluation Framework.

Monitoring water quality during dredging and disposal activities to ensure impacts are identified and actions are modified as

necessary.

Minimizing impacts through techniques such as erosion and sedimentation control and other construction best management

practices to minimize soil loss, compaction, fugitive dust, and runoff to sur face waters.

Documenting affected cultural resources and incorporating appropriate mitigation measures.

Other programs provide mitigation for impacts attributed to dam construction and operation. In the case of the four Snake River

dams, the Lower Snake River Fish and Wildlife Compensation Plan (Corps, 1983), a congressionally authorized program, provides

fish and wildlife mitigation for the impacts caused by the construction and operation of the four dams and reservoirs. The proposed

woody riparian program would further the goals of this particular mitigation plan. Mitigation for salmonid fishery impacts includes

construction and operation of several fish hatcheries and their satellite facilities to provide salmon and steelhead for commercial and

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sport fishermen. Mitigation for wildlife impacts includes maintenance of irrigated and non- irrigated HMU's on Corps-owned land

adjacent to the lower Snake River. It also includes the purchase and development of additional lands in the lower Snake River basin

suitable for wildlife habitat development.

Other Federal laws contain provisions to protect and mitigate impacts to the aquatic environment. The Corps conducts a Clean

Water Action Section 404(b)(1) evaluation, which includes evaluating alternatives that do not impact or have a lesser impact on

aquatic environment. The evaluation also includes an analysis of the unavoidable adverse impacts and ways to minimize those

impacts. The Corps prepared a 404(b)(1) evaluation for the DMMP/EIS and it is included as Appendix I. This appendix is being

coordinated with state agencies.

The ESA compliance process will also identify ways to reduce or avoid impacts to listed species and their habitat. In their Biological

Opinion for the DMMP, NMFS identified reasonable and prudent measures that would minimize the impacts to listed anadromous

fish species and their habitat. In their response document, the USFWS provided similar recommendations for listed terrestrial and

non-anadromous fish species. See Appendix F and G for details.

2.7 EVALUATION/SELECTION OF PLAN

The Corps evaluated each of the plans identified previously as "selected for further consideration" based on the following criteria:

Will the plan maintain the navigation channels of the system?

Will the plan provide optimal use of material dredged from the reservoirs?

Will the plan maintain sufficient flow capacity through the Lewiston levee system?

Does the plan maximize environmental benefits/minimize environmental impacts?

Does the plan have a favorable cost/benefit ratio?

Does the plan allow for adaptive management through the 20-year period of the DMMP?

Does the plan complement regional ESA habitat goals?

Is the plan regionally acceptable?

Does the plan address comments identified through the public review process?

The sensitivity of plan measures to variable parameters is discussed in appendix C, Economic Analysis. As also discussed in appendix

C, the risk and uncertainty of plan measures were evaluated through the use of the Corps’ Hydrologic Engineering Center Flood

Damage Assessment model that performs a risk-based analysis of flood control alternatives.

The environmental effects of the four alternatives are discussed in section 4. When preparing the effects analysis, the Corps

considered unavoidable effects, short-term uses, long-term productivity, and irreversible or irretrievable commitments of resources.

The Corps also considered direct, indirect, and cumulative effects. Table 2-8 summarizes the environmental effects of each of the

four alternatives. More detailed discussions of environmental effects are found in select appendices. Appendices F and G contain

the Biological Assessments that evaluated the effects of the preferred alternative on plant and animal species listed under the ESA.

Appendix K provides a detailed analysis of the effects of the alternatives on aquatic organisms.

Table 2-8

Environmental Effects Summary Matrix

Discipline

Alternative 1

No Action (No Change) -

Maintenance Dredging,

With In-Water Disposal

Alternative 2

Maintenance Dredging

With In-Water Disposal

To Create Fish Habitat

And A 3-Foot (0.9-m)

Levee Raise

Alternative 3

Maintenance Dredging

With Upland Disposal

And A 3-Foot (0.9-m)

Levee Raise

Alternative 4

Maintenance Dredging

With Beneficial Use

Of Dredged Material

And A 3-Foot (0.9-m)

Levee Raise

Aquatic Resources

Direct and indirect, minor,

short-term effects on food

source for aquatic species.

No long-term effects

anticipated. Potential

beneficial effects from

creation of some in-water

fish habitat.

Direct and indirect, minor,

short-term effect on food

source for aquatic species.

No long-term effects

anticipated. Potential

beneficial effects (greater

than Alternative 1) from

creation of shallow water

fish habitat.

Direct and indirect, minor,

short-term effect on food

source for aquatic species.

No long-term negative

effects anticipated. No

creation of in-water fish

habitat.

Direct and indirect, minor,

short-term effect on food

source for aquatic species;

no long-term negative

effects anticipated.

Potential beneficial effects

from creation of shallow

water fish habitat and/or

beneficial use that may

restore habitat.

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Terrestrial

Resources

Indirect, short-term minor

effects on terrestrial

wildlife and habitat.

Similar effects as

Alternative 1: Minor,

short-term, indirect

impacts on terrestrial

species through disruption

of habitat from levee raise

and displacement during

dredging.

Direct, moderate effects to

terrestrial species from

loss of habitat at upland

disposal site and

disruption of habitat from

levee raise. Positive effects

from habitat creation in old

borrow area at disposal

site.

Indirect, minor, short-term,

negative effects through

disruption of habitat from

levee raise; potential

long-term positive effects

from beneficial use of

dredged material to create

upland habitat and woody

riparian habitat.

Endangered

Species

Fish - "May affect

and would likely

adversely affect"

salmonids but no

jeopardy to listed

species; "may affect,

not likely to affect"

bull trout.

Terrestrial Wildlife -

"May affect, not likely

to adversely affect"

bald eagle.

Plants - "May affect,

not likely to

adversely affect" Ute

ladies' tresses and

water howellia; " no

effect" on Spalding's

silene.

Same effects as

Alternative 1.

Same effects as

Alternative 1.

Same effects as

Alternative 1.

Recreation

Minor, short-term impact

on access to portions of

the river for recreational

boats near proposed

dredging and disposal

activities. Maintains ability

to use recreational

facilities.

Minor, short-term, direct

impact due to disruption of

recreational facilities in

Lewiston area due to levee

raise, and minor

short-term impact to

recreational boating near

dredging and disposal.

Maintains ability to use

recreational facilities.

Same effects as

Alternative 2 except for

dredged material disposal.

Minor indirect effects to

recreational users in the

vicinity of the upland

disposal. Maintains ability

to use recreational

facilities.

Same effects as

Alternative 2. Potential

long-term, beneficial effect

from beneficial use of

dredged material if used to

enhance recreation sites.

Maintains ability to use

recreational facilities.

Cultural

Resources

Known submerged

cultural properties would

be avoided to the

maximum extent

practicable during

dredged material disposal

and management

activities.

Same effects as

Alternative 1.

Same effects as

Alternative 1. Cultural

properties in vicinity of

upland disposal site would

be avoided.

Same effects as

Alternative 1. Potential

long-term beneficial uses

would be evaluated as

proposals are developed.

Socioeconomics

Long-term, positive effect

from maintaining

navigation. Indirect,

long-term, moderate

negative effect from

greater potential flood risk

(no levee raise). Minor

effects could occur.

Low-income and minority

populations not

disproportionately

affected.

Long-term, positive effect

from maintaining

navigation. Direct,

short-term and long-term

positive effect from levee

raise due to added jobs

and materials required by

levee construction.

Reduction of flood risk

from levee raise.

Low-income and minority

populations not

disproportionately

affected.

Same effects as

Alternative 2.

Same effects as

Alternative 2.

Transportation Maintains existing

transportation systems.

Direct, short-term, minor

effect on roadways from

proposed levee/road raise

construction activities.

Same effects as

Alternative 2.

Same effects as

Alternative 2. Potential

positive effect if dredged

material is used for

transportation projects.

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Geology and Soils Local displacement of soil

and alluvial material.

Potential short-term effect

to soils in the vicinity of

levee raise due to

construction activities.

Potential short-term effect

to soils in the vicinity of

levee raise. Long-term

effects on soils at upland

disposal site due to

construction and disposal

activities.

Potential short-term effect

to soils from

implementation of

beneficial use due to

construction activities.

Water

Quality/Water

Resources

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity.

Wetlands - No effect.

Flood Plains - No

impacts.

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity.

Wetlands - No direct

effect. Minor indirect

effects associated

with levee raise.

Flood Plains - Minor,

short-term impact at

proposed upland

containment site.

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity.

Wetlands - No direct

effect. Minor, indirect

effects associated

with levee raise and

upland disposal.

Flood Plains - Minor,

short-term impact at

upland disposal site.

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity, and

placement of fill in

shoreline areas for

woody riparian

habitat creation.

Wetlands - Minor

direct effect from

woody riparian

habitat creation

adjacent to wetland.

Minor indirect effects

associated with levee

raise.

Flood Plains - No

impact to floodplain

from woody riparian

development. Future

beneficial uses may

require assessment

of floodplain

impacts.

Hazardous, Toxic,

and Radioactive

Waste

No effects anticipated;

sediments will be tested

for contamination.

Same effects as

Alternative 1.

Same effects as

Alternative 1.

Same effects as

Alternative 1.

Air Quality

Direct, minor, short-term

effects to local air quality

due to dredging and

disposal equipment

operation.

Direct, minor, short-term

effects to local air quality

due to dredging, disposal,

and construction

equipment operation.

Direct, minor, short-term

effects to local air quality

due to dredging, disposal,

and construction

equipment operation and

upland disposal activities.

Direct, minor, short-term

effects to local air quality

due to dredging, disposal,

and construction

equipment operation,

including implementation

of beneficial use(s).

Noise

Direct, minor, short-term

effects due to noise from

dredging and disposal

equipment operation.

Same effects as

Alternative 1. Localized

minor, short-term noise

from construction levees.

Same effects as

Alternative 1. Localized

minor, short-term noise

from construction levees.

Same effects as

Alternative 1. Localized

minor, short-term noise

from construction levees.

Aesthetics

Direct, minor, short-term

effects on aesthetics from

dredging and disposal

activities.

Direct, minor, short-term

effects on aesthetics from

dredging and disposal

activities; long-term, minor

impacts from levee raise.

Direct, minor, short-term

effects from dredging.

Long-term, minor impacts

from levee raise. Direct,

minor, long-term effects

from upland disposal.

Direct, minor, short-term

effects from dredging and

disposal; long-term, minor

impacts from levee raise;

and long-term beneficial

effect to shoreline area for

woody riparian habitat

creation.

Native American

Tribal

Communities

Potential positive effects

on salmon fishing from

creation of salmon rearing

habitat and cultural

resources to be avoided.

Potential positive effects

(greater than Alternative 1)

on salmon fishing from

creation of salmon rearing

habitat.

No effects anticipated. Same effects on salmon

fishing as for Alternative 2.

Cumulative Effects

Potential positive effects

on salmonid fish from

creation of shallow-water

fish habitat. Other

resources were evaluated

regarding cumulative

Potential positive effects

on salmonid fish (greater

than Alternative 1) from

creation of shallow-water

fish habitat. Same effects

on other resources as

Potential positive effects to

terrestrial species from

filling old borrow area at

disposal site and

establishing vegetation.

Same effects on other

Same effects as

Alternative 2. Positive

effects from proposed

beneficial use of dredged

material (e.g., woody

riparian habitat

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effects and nothing was

determined to preclude

the selection of this

alternative.

Alternative 1. resources as Alternative 1.

development). Same

effects on other resources

as Alternative 1.

1

"Impacts" and "effects" are used interchangeably. Unless otherwise noted as beneficial or positive, impacts described are negative.

Table 2-9 presents a matrix comparing the four alternatives’ performance in the areas of the criteria listed above.

Table 2-9

Final Alternative Evaluation Matrix

Criteria Alt. 1 Alt. 2 Alt. 3 Alt. 4

Maintain Navigation Channels M M M M

Optimize Use of Dredged Material M MH ML H

Maintain Sufficient Flow Capacity L M M M

Maximize Environmental Benefits/Minimize Environmental Impacts M MH L MH

Provide Favorable Benefit/Cost Ratio ML MH L MH

Incorporate Adaptive Management ML M ML H

Complement Regional ESA Habitat Goals M MH L H

The ratings indicate the performance of each of the alternatives in satisfying the criteria statement.

Ratings: L—Low, ML—Medium/Low, M—Medium, MH—Medium/High, H—High

Based on the current best available information as summarized in table 2-9, the Corps determined that alternative 4 best met the

Corps’ needs while minimizing negative environmental impacts and/or maximizing environmental benefits. Therefore, the Corps

selected alternative 4 as the preferred alternative for the DMMP. As a result of the initial screening and the final evaluation of

alternatives, the Corps also determined that alternative 4 is the environmentally preferred alternative. Appendix O displays the

comment letters received on the Draft DMMP/EIS and the Corps' responses to those comments.

2.8 RECOMMENDED PLAN/PREFERRED ALTERNATIVE

The Corps’ preferred alternative or recommended plan for long-term management of dredged material is "Alternative 4 -

Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise." Alternative 4 is the preferred

plan to meet the need to maintain the navigation channels of the system, manage dredged material from the reservoirs, and

maintain flow conveyance capacity in the Lower Granite reservoir. Alternative 4 most completely and efficiently meets the project

purpose and need at the least cost, while presenting potential environmental impacts that are no greater, and often less, than other

alternatives considered. Further, the plan incorporates mitigation features that would restore valuable aquatic and terrestrial habitat

to the system. The plan represents the greatest beneficial use of dredged material that can be implemented on a programmatic

basis at this time. Furthermore, the plan incorporates an adaptive management approach that provides for on-going evaluation of

proposed dredging and dredged material management activities and opportunities to adapt and adjust actions based on these

evaluations. The plan becomes the base for cost sharing of other beneficial uses of dredged material that may be identified in the

future as each separate dredging activity is planned and executed. Beneficial uses of dredged material may be adopted on a

case-by-case basis under this plan as opportunities become available and when local sponsors agree to fulfill sponsorship

requirements. To ensure that the plan continues to optimize the use of dredged material, the Corps will coordinate potential

beneficial uses for each dredging activity with the LSMG prior to the start of dredging.

The 3- foot (0.9- m) levee raise feature is the preferred plan for maintaining the flow conveyance capacity in the Snake and

Clearwater Rivers confluence area of Lower Granite reservoir because it meets the purpose and need and produces maximum net

benefits in excess of costs. Raising the levee was found to reduce the need for dredging in the confluence area of Lower Granite

reservoir and, therefore, is considered as a part of this DMMP/EIS. Selection of the levee raise as the preferred conveyance

restoration method was based on the maximization of net benefits determined from a risk-based flood damage assessment and

annual costs amortized over the remaining 74 years of the project life. Since the original Lower Granite slackwater levee system

required no local cost sharing, this levee modification at a cost of $2.3 million is recommended to be 100 percent Federal cost.

The following sections provide detailed descriptions of the components of the recommended plan.

2.8.1 Dredging Activity

The dredging procedure to be used varies depending on the location of the dredging. For the dredging proposed for the navigation

channels, slips, and berths of the Columbia/Snake/Clearwater Rivers navigation system, mechanical dredging would be used.

Mechanical dredging methods would include clamshell, dragline, backhoe, or shovel/scoop. Based on previous dredging activities,

the clamshell method would probably be used for the larger quantities. Material would be scooped from the river bottom and loaded

onto a bottom-dump barge for in-water disposal or a bin-type barge fo r upland disposal. The contractor would be allowed to

overspill excess water from the barge while the barge is being loaded. The water would be discharged a minimum of 2 feet (0.6 m)

below the river surface. Clamshell dredges of approximately 15-cy (11.5-m3) capacity and barges with a capacity of up to 3,000 cy (2

293.7 m3) with maximum drafts of 14 feet (4.3 m) would be used. The Corps estimates it could take about 6 to 8 hours to fill a barge.

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The expected rate of dredging is 3,000 to 5,000 cy (2 293.7 to 3 822.8 m3) per 8-hour shift. The barge would then be pushed by a

tug to the disposal site. No material or water would be discharged from the barge while it is in transit. For in-water disposal, when

the barge arrives at the appropriate disposal site, the bottom would be opened to dump the material all at once. A clamshell or

excavator would be used to unload barges for upland disposal. The barge would then be returned to the dredging site for additional

loads. The contractor could be expected to work between 10 and 24 hours per day, 6 to 7 days per week. Dredging would be

performed within the established in-water work windows, which currently are December 15 through March 1 in the Snake and

Clearwater Rivers and December 1 to March 31 in the Columbia River. Multiple shift dredging workdays would be used when

necessary to ensure that dredging was completed within these windows. Dredging outside these work windows, such as

summertime, would be subject to coordination with LSMG and state and federal resource agencies and would meet the requirement

of NEPA, Clean Water Act, Endangered Species Act, and other applicable environmental laws.

Multiple shift dredging workdays would be used when necessary to complete dredging within the work windows. Mechanical

dredging methods would likely be used. The disposal plan would be the beneficial use selected for that dredging activity. Figure 2-7

displays the decision tree that would be used by the Corps to determine the disposal method and location for each activity.

Figure 2-7. Disposal Site Selection Decision Tree

Figure 2-7. Disposal Site Selection Decision Tree

Maintenance of irrigation intakes and beaches has often required small-quantity dredging [under 5,000 cy (3 822.8 m3)]. Smallquantity dredging projects would involve either mechanical methods or non-agitation hydraulic methods (irrigation int akes only) and

would include discharging to barge or truck for transport. If a truck were used, disposal of the material would be made on an

appropriate upland site. Appropriate upland disposal sites include, but are not limited to, Corps land, beneficia l use upland

applications, and local landfills. The mechanical dredging equipment for these small dredging projects may be a clamshell,

dragline, backhoe, or shovel/scoop. This small quantity dredging activity would use the in-water work window or possib ly an

alternate summer work window if one were approved for the specific project.

Following are descriptions of dredging activities anticipated in each of the five reservoirs in this system. The dredging areas

described and depicted on the plates are intended as an inclusive list of dredging locations that might be dredged in the 20-year

period of this DMMP/EIS. Many of the areas listed and shown on the plates are not considered to need maintenance dredging in the

near future.

2.8.1.1 Lower Granite Reservoir

Maintenance dredging in the Lower Granite reservoir may be done at several sites (plates 15 through 17). The largest concentration

of dredging would be at the confluence of the Snake and Clearwater Rivers in the Lewiston-Clarkston area. The area that requires

frequent dredging extends from the vicinity of Silcott Island near Snake RM 131 upstream to the U.S. Highway 12 bridge located

near Snake RM 139.5 and from the confluence at RM 139 up the Clearwater River to just downstream of Memorial Bridge at RM 2

as shown on plate 17. The Federal navigation channel extends to within 50 feet (15.2 m) of existing port structures and the Corps is

responsible for maintaining this channel. The port areas parallel the Federal channel and the ports are responsible for maintaining

access from the Federal channel. Ports have expressed interest in entering into an agreement for the Corps to dredge these areas.

The dredging area includes the Federal navigation channel and port facilities in the area. Areas in the Lower Granite reservoir that

may require dredging at some time over the next 20-year period include the Port of Wilma slip, the Port of Clarkston berthing area

on the Snake River, the Port of Lewiston berthing area on the Clearwater River, the Green Belt Boat Basin, Potlatch Corporation

dock, Hells Gate State Park moorage, Chief Looking Glass moorage, Hells Canyon Resort marina, and the irrigation intake for Chief

Timothy HMU.

2.8.1.2 Little Goose Reservoir

Maintenance dredging in the Little Goose reservoir (plates 12 through 15) would include the Federal channel downstream of the

Lower Granite navigation lock guidewall and the Federal channel opposite Schultz Bar, RM 101.5. Dredging may also be required to

maintain navigation facility clearances at the Port of Garfield, Port of Central Ferry, Port of Almota, and Boyer Park Marina. In

addition, small dredging projects of 5,000 cy (3 822.8 m3) or less would be required at the irrigation intakes of the Ridpath, New

York Bar, Willow Bar, and Swift Bar HMU's over the 20-year period.

2.8.1.3 Lower Monumental Reservoir

In Lower Monumental reservoir (plates 10 through 12) periodic dredging may be required to maintain adequate navigation

clearances into Little Goose navigation lock and at Lyons Ferry Dock and Marina. Small dredging projects may also be required to

maintain the irrigation intakes for Skookum and 55 Mile HMU's.

2.8.1.4 Ice Harbor Reservoir

Maintenance dredging in Ice Harbor reservoir (plates 8 through 10) is required periodically for the Lower Monumental navigation lock

approach channel and may be required to provide navigation clearances at Walla Walla Grain Growers at Sheffler, Louis Dreyfus

Windust Station, and Charbonneau Park boat moorage. Also, small amounts of dredging may be required periodically to maintain

the irrigation intake for the Big Flat, Lost Island, and Hollebeke HMU's.

2.8.1.5 McNary Reservoir

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In McNary reservoir (plates 2 through 8) navigation maintenance dredging is required in the downstream approach channel to Ice

Harbor navigation lock for a length of approximately 7 miles (11.3 km). Periodic dredging may also be required at the Port of

Umatilla; the Port of Benton barge slip; the Port of Pasco marine terminal, barge slip, and container terminal; the Port of Walla

Walla facilities; and the Pasco Boat Basin.

2.8.2 Dredging Template Design

The navigation dredging template of the Federal navigation channels in this system is 250 feet (76.2 m) wide and 14 feet (4.3 m)

deep below the minimum authorized pool elevation. The authorized minimum pool elevations are: 733 feet msl at Lower Granite; 633

feet msl at Little Goose; 537 feet msl at Lower Monumental; 437 feet msl at Ice Harbor; and 335 feet msl at McNary. Dredging

templates for other maintenance dredging activities would vary.

2.8.3 Dredging Quantities

Dredging quantities presented here assume a dredging cycle of 2 years; however, actual dredging frequencies are dependent on

variable sedimentation rates and actual dredging cyc les may vary from 2 to 10 years. For planning purposes, the maximum volume

of dredged material was estimated to be 300,000 cy (229 367 m3), based on a 2-year cycle, in order to maintain the designed

navigation channels in the Lower Granite reservoir. Estimated dredging cycles and dredged material volumes for the lower Snake

River and McNary reservoirs are presented in table 2-10.

Table 2-10

Estimated Dredging Cycles and Dredged Material Volumes

Reservoir

Est. Dredging

Cycle (Years)

Estimated Maximum

Volume of Dredged

Material (cy/m3)

Lower Granite 2 300,000 (229 367)

Little Goose 2 4,000 (3 058)

Lower Monumental 2 2,000 (1 529)

Ice Harbor 2 2,000 (1 529)

McNary 2 32,000 (24 466)

2.8.4 Material Types

The type of material to be dredged depends on the location of the dredging. In the Snake/Clearwater Rivers confluence area, the

Corps expects to find a mix of coarse and fine sand, silt, fine silt, and organic material (wood particles). This determination is based

on samples taken during previous dredging operations. The Corps expects to find sand in the main navigation channel and silt/fines

near the shore in such locations as the port areas and the Greenbelt Boat Basin. In the area below the Lower Granite navigation

lock, the Corps expects to find river cobbles 2 to 6 inches (5.1 to 15.2 cm) in diameter with little fines and possibly some large rock

up to 18 inches (45.7 cm) in diameter. Samples taken earlier from the Ice Harbor navigation channel indicate the material is rock

with some river cobble (Corps 1997). The materials expected in the downstream approach channel of Lower Monumental based on

previous Corps experience is river cobble and rock (Corps 1997). In general, dredged materials would be composed mostly of

sediments containing a mixture of silts, sands, gravels, and cobbles carried by inflowing waters as suspended and bedload

material. Based on previous dredging experience, 85 percent of the material to be dredged is expected to be sands, gravels, and

cobbles and 15 percent of the material is expected to be silts and finer-grained material.

2.8.5 Dredged Material Management Process

2.8.5.1 Beneficial Uses Option

Each time a dredging activity covered under this DMMP/EIS is planned, the following steps would occur:

The Corps would notify parties such as the ports, municipalities, environmental groups, agencies, and others known to have

an interest in the beneficial use of dredged material. The Corps would provide the location, estimated quantity, dredging

method, expected characteristics of dredged material, and estimated time of the dredging activity. The Corps notification would

precede the proposed dredging activity by several months to allow time to negotiate an agreement with a local sponsor for the

beneficial use of the dredged material.

A public notice would be published and distributed prior to the dredging activity.

Beneficial uses may be performed by the Corps at its own expense or beneficial uses may be achieved when a local sponsor is

willing to contribute a share of the cost. Beneficial uses performed by the Corps must be the least costly while meeting

environmental requirements and being consistent with sound engineering practices. Beneficial uses cost-shared with a local

sponsor do not have to be the least costly. Section 204 of Water Resources Development Act of 1992, as amended, authorizes the

Secretary of the Army to implement projects for the protection, restoration, and creation of aquatic and ecologically related habitats,

including wetlands. Project implementation is conditional, based on non-Federal interests entering into a cooperative agreement to

provide 25 percent of the cost associated with project construction and agreeing to pay 100 percent of operation, maintenance,

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repair, replacement, and rehabilitation costs. The cost of a beneficial use project is the difference between the base dredging

disposal cost and the dredging and disposal costs of the beneficial use project. Dredged material may also be used in other ways,

provided additional cost to the U.S. government is not incurred. This DMMP/EIS identifies the basis for determining the least-cost

option for dredged material disposal. At any time, the Corps, with the consent of a non-Federal interest, can identify another

beneficial use, and the non-Federal interest would be given reasonable opportunity to finance the additional cost.

The opportunities that currently exist and could be considered for early implementation are:

Fish Habitat Creation (Figure 2-8)

Woody Riparian Habitat Creation

Hanford Site Capping (Federal)

Potting Soil (business)

Riparian Habitat Restoration

Port of Wilma Fill

Fill of Non-Federal Public Land

Highway or Road Construction

These opportunities are described in detail in section 2.5.4.

Figure 2-8. Cross Section of the Phased Development Disposal Technique for Creating Shallow Water Habitat

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2.8.5.2 Unsuitable Material Disposal Option

A contingency upland disposal site has been identified to provide storage for dredged material that may, for whatever reason, need

to be deposited on a separate upland site. A dredged material evaluation framework would be used to guide the evaluation of

dredged materials and determine the appropriate management of those sediments (see Section 3.9). Based on existing sediment

data, contaminated sediments that would be unsuitable for in- water disposal or other beneficial uses (per the framework) are not

expected to be found in substantial quantities. In the improbable event that dredged material may be moderately contaminated,

unsuitable for disposal in-water, but suitable for disposal in an unlicensed upland site, it would be isolated at the Joso upland

disposal site (RM 56.5 to RM 58.6), and appropriate confinement measures would be taken to isolate this material (e.g., installation

of an impervious liner to prevent leaching of unsuitable or contaminated materials). Should the material be uncontaminated, but not

suitable for disposal in-water (e.g., too much silt for use in creating shallow-water fish habitat), the material would be disposed of at

Joso, but in a different location from the moderately contaminated material.

Any use of the Joso site would require reconstruction of some facilities and construction of others. The existing barge slip would

need to be dredged to restore access. The barge slip would also be reconstructed using anchored sheet pile to provide vertical

walls and tie off facilities. Temporary dredged material dewatering and storage areas with containment berms and detention ponds

would be constructed adjacent to the slip. The material would be off- loaded from the barges and placed in the temporary storage

for dewatering, then would be loaded onto trucks for transport to the disposal area. The material would then be placed in lifts using

track-type tractors and compacted, resulting in a large structural fill conforming to the established final topography for the disposal

area. Areas that reach final grades would be restored on a periodic basis by placing 6 inches (15.2 cm) of topsoil and re-seeding

with native grasses to achieve a vegetative cover similar to the surrounding site areas. Filling the gravel pit with sediment and

seeding it to grass would improve the site’s value as wildlife habitat.

Construction of the Joso facilities would likely be done in stages, depending upon availability of funding. The first stage would

include dredging the barge slip and developing the off-loading and temporary storage facilities. If needed, this construction would

begin in fall 2002 so the site will be ready to accept any unsuitable material dredged during the proposed 2002-2003 dredging. The

temporary storage facilities would have the capacity to contain all the material directed to the site in 2002-2003 without requiring

removal of any of the material to the permanent storage areas on the site. The second stage would be the construction of the

containment berms, liner, and access roads for the permanent storage areas. These will be constructed concurrently with the

temporary storage facilities if funding is available. If funding is not available the first year, they will be constructed at the first

opportunity when funds do become available.

2.8.6 Levee Raise

For the 3-foot (0.9-m) levee raise alternative, an earth embankment raise is proposed. The levees would be raised a maximum

height of 3 feet (0.9 m) and would consist of removing recreation paths and adding height to the levee using embankment of

impervious gravel (20 percent to 30 percent fines). Generally, the side slopes would be 2:1 on the front slope (river side) with flatter

back slopes to accommodate local conditions. A 12-foot (3.7-m) top width would be provided for access and maintenance and

recreational paths would be reestablished. The top of the existing levee would first be excava ted to the impervious core and filter to

allow the new impervious gravel backfill to tie to the existing core and filter. In areas or conditions that require a 2-foot (0.6-m) or less

raise, the extended levee slopes would be steepened to 1.5:1, providing the additional levee height without changing the footprint or

impacting adjacent facilities. Highway 129 and Snake River Road upstream of Asotin would be modified.

The levee raise would not occur until after 2005. There is little risk of flooding in the near term since the next few dredging

operations for navigation channel maintenance would also provide additional flow conveyance capacity in the Lewiston area, even

though the protection level would remain below the SPF. However, delaying the levee cons truction date until after 2005 would allow

consideration of the biological information available at the checkpoints in 2003 and 2005 for the NMFS 2000 Biological Opinion for

Reinitiation of Consultation of the Federal Columbia River Power System, Including the Juvenile Fish Transportation Program, and

19 Bureau of Reclamation Projects in the Columbia Basin, which may impact the status and operating criteria of the four lower

Snake River dams and reservoirs. Once the future operating criteria has been determined, and if that criteria still requires a levee

raise, the construction could begin once funding is made available.

2.8.7 The 2002-2003 Dredging

The Corps has identified the first dredging activity that would be conducted under the DMMP/EIS. This dredging is currently

proposed for winter 2002-2003 and includes dredging the navigation channel at the confluence of the Snake and Clearwater Rivers,

several port facilities in the Lewiston-Clarkston area, several recreation facilities in Lower Granite and Little Goose reservoirs,

navigation lock approaches to Lower Granite and Lower Monumental, and several other potential areas. The Corps briefed the

LSMG, which provided input on the proposed 2002-2003 dredging and dredged material management. The Corps is currently

proposing using woody riparian habitat creation at Chief Timothy as a primary beneficial use of dredged material. In-water disposal

to create fish habitat in Lower Granite reservoir (RM 116) would be a secondary beneficial use of the dredged material if biological

surveys indicate the Chief Timothy site would not be available. Appendix N provides a detailed description of the proposed dredging

areas, the disposal plan, the sediment contaminant analysis, and the environmental impacts specific to this dredging activity.

2.8.8 Monitoring

The Corps anticipates the need to perform various types of monitoring of the dredging and disposal activities. Appendix M presents

the proposed monitoring program for the DMMP. Monitoring would include the following parameters:

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water quality and sediment quality;

biological;

physical;

cultural resources.

Appendix M describes the process for determining monitoring needs and methods. Monitoring activities will be coordinated with the

LSMG.

2.8.9 ESA Consultation Provisions

The Corps consulted with the National Marine Fisheries Service (NMFS) and the U.S. Fish and Wildlife Service (USFWS), pursuant

to the requirements of the Endangered Species Act (ESA). The Corps prepared biological assessments (BAs) evaluating the

potential effects of the proposed alternatives on species listed under the ESA. Full documentation of these consultations is

presented in Appendix F (for NMFS) and Appendix G (for the USFWS).

NMFS determined, based upon implementation of a series of Reasonable and Prudent Measures, the Recommended Plan would

not cause jeopardy to, or adversely modify the Critical Habitat of anadromous fish species listed under the ESA. Specifically, the

Biological Opinion determined that the effects of the Recommended Plan will not jeopardize the continued existence of endangered

Snake River sockeye, threatened Snake River Fall chinook, threatened Snake River Spring/Summer chinook, threatened Snake

River Basin steelhead, endangered Upper Columbia River Spring chinook, endangered Upper Columbia River steelhead, or

threatened Middle Columbia River steelhead or result in the adverse modification or destruction of their Critical Habitat.

The Corps completed informal consultation with USFWS for ESA- listed non-anadromous fish and terrestrial species that might be

affected by implementation of the DMMP. In their concurrence letters, USFWS identified several conditions or assumptions,

including the need for consultation on specific dredging and associated actions and compliance with the terms of the USFWS

Biological Opinion for the Federal Columbia River Power System regarding bull trout in the lower Snake River system (see Appendix

G). The Corps intends to comply with these conditions when implementing the DMMP.

2.8.10 Regional Acceptability and Public Comments

The acceptability by states, other Federal agencies, stakeholders, special interests, local governments, tribes, and the general

public was assessed through the public review process for the DMMP/EIS and approximately 28 comments of the parties were

considered in this Final DMMP/EIS. It seems generally accepted that to maintain the current navigation activities, maintenance

dredging and disposal of resulting dredged material must be done. However, the public review process revealed that regional

interest focused on water quality, ESA-listed fish species, and cultural resources. Several commentors expressed concerns

regarding possible impacts from the proposed dredging and disposal activities within the project area. The method and timing of the

dredging and location of disposal is of interest to the public and stakeholders. The local governments affected by the levee raise

have concerns with timing and the effect it might have on future river front development. For review of these comments and

responses, see Appendix O, Response to Public Comments. The Corps considered all of these comments in the evaluation and

selection process to identify the recommended plan (preferred alternative). In an environment as described above, the

recommended plan (preferred alternative) will be acceptable to some and not to others. Regarding state or local laws and

regulations, the actions in the recommended plan (preferred alternative) are considered to be consistent. See Sections 5 and 6 for

more specifics.

2.8.11 Other Considerations

Other important factors that were considered include, but are not limited to:

How the alternatives affect long-term and short-term productivity

If there are irreversible and/or irretrievable commitment of resources

If there are unavoidable adverse impacts

If mitigation is needed or required

Whether the best information or science was available

Which alternative is environmentally preferable

Whether the recommended plan (preferred alternative) is in accordance with declared policies of NEPA and in compliance with

Federal laws and regulations.

Other factors involving technical feasibility were considered. Even though this is a very basic criterion, it is an extremely important

one, in that the recommended plan (preferred alternative) must be constructible and implement able. The rationale for selecting

Alternative 4, Maintenance Dredging with Beneficial Use of Dredged Material and a 3-foot (0.9-m) Levee Raise, is a composite of

analyses, information briefings, evaluations, hundreds of years of combined technical expertise, and comments concerning the

factors that may or may not be affected by the alternatives discussed in the DMMP/EIS. The selection of the recommended plan

(preferred alternative) resulted from the evolution and development of a collection of scientific data and information presented in this

DMMP/EIS, its associated appendices, and supporting research materials and reports. Although not without uncertainties, the

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information contained herein was the result of researchers, contractors, Corps’ staff, etc. and, in the Corps’ judgment, is the best

available science and information to date and contains sufficient rationale for selecting this plan/alternative.

Section 3

Affected Environment

This section presents the existing environmental conditions in the DMMP study area that could be affected by the alternatives

considered in this EIS. The descriptions of the biological, physical, cultural, and socioeconomic resources serve as a basis for

evaluation and comparison of the anticipated effects of the plan alternatives evaluated in section 4. In most cases, sufficient existing

data and documentation were available to allow reasonable assessments of the impacts to a particular resource. The Feasibility

Study, the Corps Interim Columbia and Snake River Flow Improvement Measures for Salmon Final Supplemental EIS (Corps, 1993),

the Final Columbia River System Operations Review EIS (BPA et al., 1995), and the Columbia River Flow Measures Options

Analysis (Corps, 1992) evaluated some of the same resources and are incorporated by reference. For some resources, only limited

data were available. In these instances, the limitations of the data are documented and the impact analysis was more qualitative in

nature.

3.1 AQUATIC RESOURCES

Construction of the Snake and Columbia River Federal dams altered the character of the natural river from running to impounded

water and created over 124 miles (200 km) of reservoirs on the lower Snake River and 62 miles (100 km) of reservoir behind McNary

on the Columbia River. A continuing effect of dam construction is the deposition of sedimentary material in the lower velocity areas

within the system. For example, in Lower Granite reservoir, sediment deposition has occurred around the confluence of the Snake

and Clearwater Rivers and downstream to Silcott Island. The Corps is proposing to conduct navigation and maintenance dredging

on the lower Snake River, the mid-Columbia River (specifically McNary reservoir in Washington and Oregon), and at the mouth of

the Clearwater River in Idaho and Washington.

This section describes the lower Snake River and McNary reservoirs, some of their characteristics, and the habitats used by the

various fish species. A summary of available data on fish spawning requirements, life histories, and predation of resident fish on

juvenile salmonids is also presented.

3.1.1 Fish

The Columbia and Snake River systems support large and varied populations of fish. Within the project area, anadromous

salmonids including chinook (O. tshawytscha), coho (O. kisutch), and sockeye (O. nerka) salmon and steelhead (Oncorhynchus

mykiss) are seasonally present. Resident fish, of both native and introduced species, are also abundant in these reservoirs with

community structure generally similar among reservoirs (Bennett et al., 1983). Of the current resident ichthyofauna of the reservoirs,

about half are native species and half are introduced. Major resident species of concern include the white sturgeon (Acipenser

transmontanus), northern pike minnow (Ptychocheilus oregonensis), and smallmouth bass (Micropterus dolomieu).

3.1.1.1 Anadromous Fish

Seven anadromous fish species found within the project area have been designated as Evolutionarily Significant Units (ESU's) and

are listed as Threatened or Endangered under the ESA. These species include Snake River Sockeye Salmon, Snake River Basin

Steelhead, Snake River Basin Spring/Summer and Fall Chinook Salmon, Upper and Middle Columbia River Basin Steelhead, and

Upper Columbia River Spring Chinook Salmon. Within the project area, Columbia River stocks are thought to occur primarily in

McNary reservoir with few straying into the Snake River. Snake River basin stocks occur throughout the lower Snake River and

McNary reservoir. Although not presently listed, Pacific lamprey is also a species of concern in the project area. Historically, white

sturgeon exhibited diadromus behavior in the project area but were isolated after construction of the dams and will be discussed in

the resident fish section.

The following analysis addresses a small portion of the total life history of these fish with emphasis placed on the threatened or

endangered stocks. While a salmon or steelhead typically lives for 3 to 6 years, the duration spent within the direct influence of the

hydro system is limited. The Corps is concerned, however, with that period of fresh water residence when the Federal Columbia

River Power System (FCRPS) does specifically influence these stocks. This period may occur for a few days to a few months as

juvenile salmonids either migrate through these areas or rear within them prior to migrating to the ocean. Also, depending on the

stock of fish, adults will be influenced by the FCRPS for weeks to months as they migrate upriver. The life history and status of

various stocks, with emphasis on those originating in the Snake River and McNary reservoirs and their headwaters, are presented in

this section with migration windows shown in figure 3-1.

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Figure 3-1. Typical Anadromous Salmonid Migration Windows

3.1.1.1.1 Sockeye Salmon

One run of ESA-listed sockeye salmon is known to occur in the project area. Snake River sockeye salmon were listed as

endangered in November 1991.

Sockeye salmon are unique in that they are the only species of Pacific salmon that depends on higher elevation tributary lakes in

the Salmon River subbasin of Idaho for spawning and rearing (Gustafson et al., 1997). Adult Snake River sockeye salmon passage

typically occurs in the project area from June through early August. Juveniles rear in lakes for 1 to 2 years and typically actively

migrate to the ocean (with minimal rearing in the reservoirs) from April to July; however, some migration can occur through

November.

The McNary reservoir and the lower Snake River corridor are designated as Critical Habitat for migration passage of wild Snake

River sockeye salmon. Critical Habitat attributes and Essential Fish Habitat (EFH) components for potential rearing or overwintering

for Snake River sockeye salmon are not present in the McNary reservoir, lower Snake River corridor, or any of the proposed project

areas. The components of designated Critical Habitat and EFH for juvenile and adult migration passage are present between

mid-March and mid- August. No spawning habitat for sockeye salmon is present in the proposed project area. Therefore, no

individuals should use the dredging activity areas of the Columbia, Snake, or Clearwater Rivers for rearing, feeding, or overwintering

during the designated in-water work period. This includes the off-channel areas that will only be dredged when water temperatures

exceed 73 °F (22.7 °C). The high temperatures make the proposed dredging areas unsuitable for sockeye salmon.

3.1.1.1.2 Spring/Summer Chinook Salmon

Two runs of ESA- listed Spring/Summer Chinook Salmon seasonally exist in the project area. These include the Upper Columbia

River Spring ESU, listed as endangered in 1999, and the Snake River Spring/Summer ESU, listed as threatened in 1992.

Upon returning to fresh water after spending 2 to 3 years in the ocean (Howell et al., 1985), adult spring chinook salmon typically

pass through the McNary and Snake River reservoirs from mid-April to mid-June with 90 percent passing in the month of May

(Stuehrenberg et al., 1995). Adult summer chinook salmon typically pass the main stem dams by September, with the majority

passing between mid-June and mid-August. All populations are believed to spawn from August through October in tributaries

upstream of hydro project influences (Corps, 1999). In tributary systems with both spring and summer runs, spring chinook salmon

tend to spawn farther upstream and earlier than summer run salmon (Matthews and Waples, 1991); however, spawning area and

timing may overlap in some areas. This overlap is one of the reasons that NMFS may designate these fish as one stock

(spring/summer) in their ESA listing. Within the Snake River system, there are five major spawning and rearing basins for

spring/summer chinook salmon. These include the Clearwater, Grande Ronde, Salmon, Tucannon, and Imnaha rivers. Columbia

River stocks spawn and rear in the Wenatchee, Entiat, Methow, and Okanogan basins.

Juveniles typically rear in the tributaries for more than a year, migrating downstream during their second spring as yearlings from

about early April to June. Snake River spring and summer chinook salmon have the same juvenile out-migration age and timing,

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with the majority of these fish passing the dams in April and May. Little, if any rearing occurs in the main stem Snake and Columbia

Rivers (Chapman et al., 1995) as indicated by a relatively short reservoir residence time of juvenile spring chinook salmon (Giorgi

and Stevenson, 1994). However, a few individuals of spring chinook salmon from undetermined origin have been documented as

using backwater areas of the McNary reservoir for rearing, feeding, or overwintering (Easterbrooks, 1995, 1996, 1997, 1998) during

the period sampled (mid-March through July).

The McNary reservoir is designated as Critical Habitat for migration passage of wild Upper Columbia River Spring and Snake River

Spring/Summer Chinook Salmon. Designated Critical Habitat and EFH for potential rearing, overwintering, or resting during juvenile

migration may be present in the McNary reservoir project areas for Upper Columbia River Spring Chinook Salmon between

mid-March and mid-June.

The lower Snake River was designated as Critical Habitat for migration passage of wild Snake River Spring/Summer-Run Chinook

Salmon. Critical Habitat attributes and EFH components suitable for potential rearing or overwintering for Snake River

Spring/Summer-Run Chinook Salmon are likely present in the proposed project areas during the winter in- water work window and

in November at the Joso site. No suitable habitat would be available in off-channel dredging areas if water temperatures exceed 73

°F (22.7 °C).

3.1.1.1.3 Fall Chinook Salmon

One run of ESA-listed Fall Chinook Salmon is known to occur in the project area. The Snake River Fall Chinook Salmon ESU was

listed as threatened in 1992.

After 2 to 3 years in the ocean, adult wild Snake River Fall Chinook Salmon return to the Snake River between late summer and

early winter with spawning activity beginning around mid-October (Connor, 1994). The current major spawning area for Snake River

Fall Chinook Salmon exists in the 103 miles (166 km) of the Snake River below Hells Canyon Dam and in the lower reaches of the

Clearwater, Grande Ronde, Imnaha, Tucannon, and Salmon Rivers. The majority of redds annually appear clustered in specific

areas, such as at Snake River RM 162 in 1991 (Connor, 1994). Spawning of fall chinook salmon has also been known to occur in

Little Goose, Lower Monumental, and Ice Harbor reservoirs, but only in tailwater areas directly downstream of the dams' bypass

outfalls, where water velocity is high and substrate is relatively large (Dauble et al., 1995 and 1996).

Little is known about timing of emergence from the gravel for Snake River Fall Chinook Salmon (Howell et al., 1985); however,

Bennett and Shrier (1986) and Bennett et al. (1988, 1990, 1991, 1993a, 1993b) captured subyearling chinook salmon in Lower

Granite reservoir in April, suggesting emergence can occur in March to early April. After emergence and initial dispersal, fall chinook

salmon exhibit a high fidelity for lower velocity backwater areas for rearing in the main stem river and reservoir reaches of the

Columbia and Snake Rivers. Bennett and Shrier (1986) and Bennett et al. (1988, 1990, 1991, 1993a, 1993b) consistently captured

subyearling chinook salmon over low gradient, low velocity, sandy substrates in Lower Granite reservoir, likely an anti-predation

strategy at locations that produce suitable macroinvertebrate prey abundance. Habitat having these physical characteristics can be

effectively constructed in any of the lower Snake River reservoirs with appropriate placement of dredged material. Subyearling

salmon migrate through reservoirs more slowly than yearling chinook salmon and spend more time in reservoir habitats for rearing

(Rondorf et al., 1990; Curet, 1994) since they are not afforded the additional year of freshwater rearing and overwintering in the

subbasins that yearling chinook salmon are allowed.

Most juvenile fall chinook salmon from the Snake River migrate to the ocean as subyearlings (Bjornn, 1960). The wild juvenile fall

chinook salmon typically pass mid-June through September, with double peaks in mid-July and some lingering proportion of the

annual migration population lasting through November. Passive Integrated Transponder (PIT)-tag detections of 1993-1995 brood

year juvenile fall chinook salmon from the Clearwater River were recorded in the spring of 1994-1996 at some lower Snake River

dams (Arnsberg, 1996). It is apparent from these detections that some fall chinook salmon migrate to the ocean as yearlings rather

than as subyearlings.

3.1.1.1.4 Steelhead

Three runs of ESA- listed steelhead are known to occur in the project area. Upper Columbia River and Snake River Basin ESU's

were listed in 1997 and the Middle Columbia River ESU's were listed in 1999.

Upon returning to fresh water after spending 1 to 4 years in the ocean, most adult steelhead pass McNary between May and

November and Lower Granite between July and December. Some adult steelhead are known to overwinter in the lower Snake River

and begin migrating toward spawning grounds the following spring as water temperatures begin to warm up. Steelhead typically

spawn in tributaries outside the influence of the hydrosystem between December and June (Bell, 1991). Unlike salmon species,

steelhead have the potential to spawn numerous times; however, the current proportion of repeat spawners is expected to be low

(Corps, 1999). Adult steelhead may be in the areas proposed for dredging and disposal in the reservoirs during the proposed

dredging periods.

Juvenile steelhead rear in freshwater streams for 2 to 3 years prior to out-migrating. Out-migrants actively migrate through the

reservoirs from late April through June and typically rear very little during their out-migration.

3.1.1.1.5 Pacific Lamprey

Adult Pacific lamprey enter the fresh water between April and June, migrating to spawning areas by September (Close et al., 1995).

Spawning typically occurs in June and July of the following year in low-gradient-flowing- water stream sections where gravel is

deposited. Spawning has been observed in small tributaries entering main stem reservoirs (Wydoski and Whitney, 1979). Lamprey

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distribution extends up the Snake River to Hells Canyon Dam and to Chief Joseph Dam on the Columbia.

After hatching, ammocoetes (a stage of juvenile lamprey) drift downstream to burrow into the substrate sand or mud. Ammocoetes

rear in the substrate for 5 to 6 years when they metamorphose into juvenile lamprey and out- migrate to sea between April and July.

After 20 to 40 months, the adults return to spawn in the river systems (Kan, 1975).

3.1.1.2 Resident Fish

3.1.1.2.1 General Ecology

Resident fish species in the lower Snake River and McNary reservoirs include a mixture of native riverine species as well as

introduced species that are associated with lake- like conditions (Bennett et al., 1983; Bennett and Shrier, 1986; Hjort et al., 1981;

Mullan et al., 1986). Cold-water resident species (such as trout and whitefish) that were once common in the Columbia and Snake

Rivers have declined since the construction of the dams and have been replaced by cool- and warm-water species. Species

composition has changed due to the blockage of spawning migrations and modification of habitats (Mullan et al., 1986). The prey

base has also changed since the construction of the dams, probably contributing to the decline of cold-water species (Sherwood et

al., 1990).

Resident fish in the reservoirs occupy numerous habitats and often use separate habitats for different life history stages (Bennett et

al., 1983; Bennett and Shrier, 1986; Hjort et al., 1981; Bennett et al., 1991). Each reservoir has three general zones that are

characterized by different habitats (Hjort et al., 1981). The first zone is the forebay area, which is typically lacustrine (lake-like) in

nature. At the upper end of the reservoir is a second zone that tends to be shallower and have significant water velocities. In

between these two zones is a transition area that changes in the upstream end from riverine to more lake- like in the downstream

direction. Each zone can include several habitat types; however, most can be characterized as either backwater (including sloughs

and embayments) or open-water habitats (Hjort et al., 1981; Bennett et al., 1983).

3.1.1.2.2 Habitat Use

Backwaters and embayments generally provide low water velocity, slightly warmer water, finer substrate, and submersed and

emergent vegetation. Bass (Micropterus spp.), crappie (Pomoxis spp.), bluegill (Lepomis spp.), yellow perch (Perca flavescens), and

carp (Cyprinus carpio) use backwater areas for spawning and rearing (Bennett et al., 1983; Bennett and Shrier, 1986; Hjort et al.,

1981; Bennett et al., 1991; Zimmerman and Rasmussen, 1981). The centrarchids (sunfishes, including bass and crappie) normally

spawn in shallow water less than 6.5 feet (2.0 m) deep (Bennett et al., 1983) while yellow perch generally utilize waters less that 10

feet (3.0 m) deep (Stober et al., 1979). Spawning and incubation times vary between species; however, most of these backwater

species spawn from May through mid-July (Corps, 1999).

Cyprininds (minnows, dace, and chub); catostomids (suckers); walleye (Stizostedion vitreum); and sandroller (Percopsis

transmontanus) spawn in open water. White sturgeon, a species that is considered non-anadromous above Bonneville (ODFW and

WDFW, 1998), spawn over areas with rocky bottoms and high water velocity (Parsley et al., 1993). Prickly sculpin (Cottus asper)

spawn in both open water and backwater based on the distribution of prolarvae (Hjort et al., 1981). Most fish larvae are generally

found in the backwaters and near-shore areas. Only yellow perch and prickly sculpin larvae are commonly found in open-water

areas. Most of the native species spawn in flowing water at the headwaters of the reservoirs or in tributary streams. Some species,

however, also spawn in the reservoirs. Northern pike minnow may spawn either in flowing water or along gravel beaches in

reservoirs (Wydoski and Whitney, 1979).

Juvenile fish are found in abundance in backwater and open-water areas where flowing water is found. The two habitats are

occupied by distinctly different fish species. Introduced species, which are primarily lake-dwelling fishes, are more common in the

forebay zone and backwater areas while native species are more common in the flowing water regions found in the tailrace zone

(Hjort et al., 1981; Bennett et al., 1983; Bennett and Shrier, 1986; Mullan et al., 1986).

Adult distribution is generally similar to spawning and juvenile distribution, but can change depending upon feeding strategy. Adults

may occur throughout the habitats and move seasonally or daily to different areas (Bennett et al., 1983; Bennett and Shrier, 1986;

Hjort et al., 1981). Although adults will use various habitats, lake-dwelling species are generally more abundant in shallow, slowervelocity backwater areas, and native riverine species occur abundantly in areas with flowing water (Bennett et al., 1983).

Although there is a difference in numbers, there is little difference in the species composition of the five reservoirs. Species found in

high abundance in all reservoirs include suckers, northern pike minnow, bass, chiselmouth (Acrocheilus alutaceus), and redside

shiners(Richardsonius balteatus) (Bennett et al., 1983; Bennett and Shrier, 1986; Bennett et al., 1988). Species such as crappies,

sunfish, and largemouth bass are highly abundant in backwaters of all reservoirs. Minor variations in species composition are

related to variations in the availability of backwater habitats and flowing waters in the various reservoirs.

Little Goose, Lower Monumental, and McNary reservoirs have a greater number of backwater areas than Lower Granite and Ice

Harbor (Bennett et al., 1983). The confluence of two major tributaries (Palouse and Tucannon Rivers) with the Snake River provide

additional backwater habitat in Lower Monumental reservoir. These reservoirs tend to support larger numbers of species that

depend on shallow-water habitats during some part of their life histories.

3.1.1.2.3 Bull Trout

Bull trout, listed as threatened under the ESA, are found primarily in colder streams, although individual fish are found in larger river

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systems throughout the Columbia River Basin (Fraley and Shepard, 1989; Rieman and McIntyre, 1993, 1995; Buchanan and

Gregory, 1997). Water temperature above 59 °F (15 °C) is believed to limit bull trout distribution. However, the USFWS reported 37

records of bull trout in the lower Snake River since 1991. Most were noted at adult-fish-counting stations and passed in April, May,

or June (Hayley, 1999).

Bull trout typically spawn from August to September during periods of decreasing water temperatures. Migratory bull trout

frequently begin spawning migrations as early as April and have been known to move upstream as far as 155 miles (249 km) to

spawning grounds. Temperature during spawning generally ranges from 39 to 51 °F (4 to 10 °C) with redds often constructed in

stream reaches fed by springs or near other sources of cold groundwater (Goetz, 1989). Bull trout require spawning substrate

consisting of loose, clean gravel relatively free of fine sediments.

The only subpopulations of bull trout associated with the project area spawn and rear in the Tucannon River Basin with both

resident and migratory forms present. Evidence suggests that migratory (adfluvial) bull trout from the Tucannon River also utilize the

main stem Snake River on a seasonal basis (Buchanan and Gregory, 1997). Adult bull trout that are adfluvial generally spend about

half of every year associated with a reservoir (November-May). These fish most likely forage in shallow areas where the majority of

prey exists. Depending on water conditions, bull trout will occupy deeper areas of the reservoir where water temperatures are cooler

[45 to 54 °F (7.2 to 12.2 °C)] and move to the surface when water temperatures drop to or below 54 °F (12.2 °C).

There have been several observations of adult bull trout passing Lower Monumental and Little Goose. From 1994 to 1996, 27 bull

trout passed the adult fish counting station (mainly in April and May) at Little Goose. At least six bull trout passed counters at Lower

Monumental and Little Goose in 1990 and 1992 (Kleist, 1993). Kleist also observed one bull trout in 1993 just downstream of the

count window at Lower Monumental. Furthermore, one bull trout was captured in the Palouse River below Palouse Falls in 1998.

These were likely migratory fish from the Tucannon River. However, one bull trout was observed at Lower Granite in 1998 that may

indicate fluvial fish are migrating to other upstream populations.

The status of bull trout associated with the Tucannon River was rated as "healthy" by the Washington Department of Fish and

Wildlife (WDFW, 1997), although some habitat degradation has occurred due to timber harvest and recreational use. It is not

currently at risk of extinction and is not likely to become so in the foreseeable future because of sufficient habitat protection

(wilderness designation) in the upper watershed and the lack of brook trout encroachment.

3.1.1.2.4 White Sturgeon

Historically, diadromus white sturgeon in the Columbia and Snake River system ranged freely and made extensive seasonal

migrations to optimize changing habitats (Bajkov, 1951). Dams and resulting impoundments have isolated white sturgeon

populations (North et al., 1992) and reduced habitat diversity by replacing riverine habitats with lentic environments. Populations of

fish species adapted to riverine conditions typically decline at the highest rate (Parsley et al., 1993). Landlocked populations of

white sturgeon in the Snake River are classified as a species of special concern (Mosley and Groves, 1990 and 1992) for the states

of Washington and Idaho.

Presence of young of the year (YOY) and high abundance of juvenile white sturgeon in Lower Granite reservoir indicate recruitment

has been occurring in the Lower Granite-Hells Canyon population. The high abundance of juvenile and YOY fish near the upper

end of Lower Granite reservoir also suggests that the reservoir primarily serves as rearing habitat. McCabe and Tracy (1993)

suggested that wide dispersal of white sturgeon larvae allowed more use of feeding and rearing habitats while minimizing

competition. Lepla (1994) assumed no spawning occurred in Lower Granite reservoir since velocities measured in the reservoir [0.0

to 1.96 feet per second (0.0 to 0.60 meters per second (m/s))] are below threshold levels perceived to elicit spawning [3.28 feet per

second (1.0 m/s)] (Anders and Beckman, 1993).

Parsley et al. (1996) captured YOY fish and fertilized eggs in 1994 and 1995 in the tailraces of Priest Rapids and Ice Harbor,

indicating that recruitment has been occurring in McNary reservoir. Rien and Beinegen (1997) reported the density of white sturgeon

in McNary reservoir was 0.86 fish/acre (0.35 fish/hectare), which is similar to John Day reservoir in 1990, but much less than

Bonneville or The Dalles reservoirs in 1994. The estimated proportion of white sturgeon less than 32.3-inch (82-cm) fork length in

the population estimate was smaller than that in the lower reservoirs. While this estimate may be negatively biased by gear

limitations, low recruitment is likely limiting abundance.

Seasonal changes in distribution occur in Lower Granite reservoir (Lepla, 1994). Relative numbers of white sturgeon in the upper

section of the reservoir increased from May through November, implying upriver redistribution/movement as the summer to fall

season progressed. However, multiple comparison tests indicated seasonal use of mid- and lower reservoir transects was not

significant with exception to RM 116.8 (1.6 RM upriver of Knoxway Bay). The number of white sturgeon sampled at RM 116.8 was

highest (0.31 fish/hr) only during April-July 1991 and declined sharply as summer progressed. Catch rates at RM 116.8 in 1990

were low and were also similar in 1992 (Bennett et al., 1994 and 1995). Catch rates at remaining mid- and lower reservoir locations

were low regardless of season. Movements from 0 to 16 miles (0 to 25 river km) were observed from recaptured white sturgeon with

the majority of fish traveling 0.62 to 3.1 miles (1 to 5 river km). Differences in fish size did not appear to affect distance traveled in

the reservoir. Approximately 65 percent of the fish recovered were collected within the upper 6.21 miles (10 river km) of Lower

Granite reservoir where densities of white sturgeon were highest.

3.1.1.2.5 Margined Sculpin

Margined sculpins, a federal species of concern and considered a sensitive species by the state of Washington, are a small fish

species that live in river gravels/cobbles whose requirements are poorly known. The former range of these sculpins is unknown;

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however, they currently inhabit the Walla Walla and Tucannon Rivers in Washington. Without competition, they seem to prefer cool

[55 to 66 °F (12.8 to 18.9 °C)] water, moderate to rapid current, and rubble or gravel substrate. Margined sculpins spawn in the

spring.

3.1.2 Plankton and Benthic Organisms

3.1.2.1 Plankton

Two other very important parts of the food chain that may be affected by dredging and disposal activities include phytoplankton and

zooplankton. Both phytoplankton and zooplankton are food sources for larger aquatic organisms, such as snails and small fish. In

addition, zooplankton can compose an important component to the diet of rearing anadromous and resident fish species (Bennett et

al., 1983). The use of backwater areas by numerous species may be at least partially related to the availability of prey. High

concentrations of zooplankton in the backwater areas attract smaller prey species that feed upon these organisms. In turn, high

concentrations of prey fish attract larger predator fish species. Therefore, higher concentrations of zooplankton in backwater areas

may affect the habitat selection of several species (Corps, 1999).

3.1.2.2 Benthic Organisms

The benthic community consists of organisms that live on the river bottom and provide significant input into the food chain. Benthic

plants such as algae and benthic animals such as insects, worms, snails, and crayfish are components of this community. Benthic

organisms contribute significantly to the diets of many reservoir fish species (Bennett et al., 1983). In particular, crayfish are an

important component to the diet of smallmouth bass, northern pike minnow, and channel catfish (Ictalurus punctatus) in Little

Goose and Lower Granite reservoirs (one can assume these species would be equally important in Lower Monumental, Ice Harbor,

and McNary reservoirs). Benthic production is usually minimal in shallow-water areas if the water levels fluctuate and expose the

organisms.

As reservoirs age, the invertebrate species composition and abundance convert from lotic flowing riverine macroinvertebrate species

found in the shallower and higher velocity environments of the pre-dam river to lentic or pelagic reservoir invertebrate species found

drifting in the photic zone of the deeper and slower velocity environments of the post-dam reservoir. Species abundance and

composition for benthic macroinvertebrates sampled in the early 1980's (5 to 7 years following refill) were related to habitat

differences including substrate type and size, depth, flow, and season of year (Bennett and Shrier 1986, Dorband 1980). By the

early to mid-1980's, the dominant benthic invertebrate taxa in Lower Granite reservoir had already converted to dipteran chironomid

midges and annelid oligochaete (bloodworms) (Bennett and Shrier, 1986; Bennett et al., 1988). Within a few years after reservoir

filling, Dorband (1980) already found a shift in dominant benthic taxa at RM 135, approximately four-fifths the distance upriver from

Lower Granite near the Port of Wilma. The Port of Wilma is about 4 to 5 RM's above Silcott Island at RM 131 where the hydraulic

influence of the unimpounded flow input becomes dominated by the backwater effect of the reservoir volume and lower water

velocities. Upriver of RM 135, there were more lotic species (larvae of tricopteran caddisflies, ephemeropteran mayflies, and

plecopteran black flies), while below RM 135, lentic taxa were common (dipteran chironomid midges and annelid oligochaete blood

worms). The transition zone between the lentic and lotic habitats had the lowest density of benthic macroinvertebrates, possibly

attributable to deposition from sediment input where the average water velocity across the channel slows. Species diversity of

macroinvertebrate communities at shallow sites increases with downstream movement or colonization of drifting organisms scoured

from upriver habitats, provided that like substrate and associated habitat components are available and suitable.

In the early 1980's, shoreline distributed littoral areas [less than 15.5 feet (4.7 m) deep] generally had the highest invertebrate

abundance, species diversity, and species evenness. Sites of similar depth within the reservoir appeared different based upon

location in the reservoir (as defined by river mile) with regard to benthic invertebrate numbers within and across species (Bennett

and Shrier 1986, Bennett et al., 1988). Annual and seasonal population abundance variations occurred, with increased variation

evident for species exhibiting seasonal emergence (e.g., chironomids as they pupated into adults) than species that are aquatic

through all life stages (e.g., oligochaetes). Oligochaetes are ubiquitous throughout the lower Snake River reservoir sediments.

Oligochaete biomass does not appear to vary with depth of water. While the numerical densities can fluctuate widely with a pattern

similar to chironomids, the average biomass density appears to remain relatively constant around 0.15 ounce per square yard

(oz/yd2) (5 g/m2). Oligochaetes prefer fine sediments with a high percent of organic content.

Chironomids can make up a substantial portion of the diets of certain fishes. If food is a limiting resource to fall chinook salmon

rearing and migrating through Lower Granite reservoir, then it is necessary to estimate chironomid densities as a function of depth

and substrate type. Sampling by Bennett et al. (1988) showed a statistically weak pattern of biomass and abundance when

measured by season and depth. The shallow water biomass peaks in summer at about 0.59 oz/yd2 (20 g/m2), and drops off to

around 0.15 oz/yd2 (5 g/m2) in the winter. Measured by depth, the biomass appears to be constant from 5 to 20 feet (1.5 to 6.1 m)

deep, but begins to decrease as depth increases below 20 feet (6.1 m). Chironomids are most likely located in sand-silt sediments

and decrease in both finer and coarser sediment-type environments. The chironomid communities within the lower Snake River

reservoirs are composed of several different species, thus resulting in chironomids being readily susceptible to predation by rearing

salmonid smolts across the duration of the smolt migration seasons during each of the overlapping pupation and emergence

episodes of the various chironomid species.

The role of crayfish in resident and predatory fish diets is extensively reported for every year of sampling in both Lower Granite

reservoir since 1988 (Bennett, 1988) and in the unimpounded Snake River upriver of Lower Granite reservoir (Nelle, 1999; Petersen

et al., 1999), especially for sustaining northern pike minnow and smallmouth bass. Crayfish predominantly inhabit shallow water

riprap areas from which they forage riverward for primarily oligochaetes and other soft substrate inhabitants. Crayfish have been

found at all depths in the Oxbow reservoir above Hells Canyon (Bennett, 1995), in Lower Granite reservoir during the physical

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drawdown test in 1992 (Bennett et al., 1995; Curet, 1994), and in the unimpounded Snake River between Lower Granite reservoir

and Hells Canyon Dam (Nelle, 1999). To demonstrate the importance of crayfish in sustaining predator productivity in both Lower

Granite reservoir and the unimpounded Snake River between Lower Granite reservoir and Hells Canyon Dam, Bennett et al. (1995)

observed a vertical migration of smallmouth with the 2 feet (0.6 m) per day receding water during the physical drawdown test of

Lower Granite reservoir in March 1992. Crayfish were left desiccated as they searched wetted shelter in the sediment cracks of the

30-foot- (9.1-m-) deep zone that was dewatered for several weeks. When the reservoir refilled in late March and early April, the

majority of the smallmouth bass survived and vertically migrated back up to the shallow water zones that had cover via riprap when

spring chinook smolts began migrating. Smallmouth bass consumption rates on juvenile salmonids increased in 1992 compared to

previous smolt migration years as a consequence of interception by predators that were occupying a littoral zone that was

temporarily devoid of crayfish. Crayfish recruited back to the littoral zone within the year, and smallmouth bass consumption rates

decreased in 1993 to similar rates estimated for previous and post years of sampling (Bennett et al., 1995; Bennett et al., 1997).

Studies on the Columbia River have shown the importance of benthic invertebrates, particularly Corophium salmonis, in diets of

juvenile white sturgeon (McCabe et al., 1992a; McCabe et al., 1992b). More extensive research is needed to determine significant

links between sturgeon distribution, sturgeon growth, and invertebrate abundance. Sprague et al. (1993) indicated that white

sturgeon may be feeding on organisms in the water column rather than exclusively on organisms associated with the substrate.

Corophium species (river drift organisms) were the predominant prey item eaten by YOY and juvenile white sturgeon in two

Columbia River impoundments and the lower Columbia River (Sprague et al., 1993; McCabe et al., 1992a; Muir et al., 1988).

Corophium species abundance in Lower Granite reservoir appear low (Bennett et al., 1991); however, crayfish were abundant near

the upper end of Lower Granite reservoir.

Cochnauer (1981) reported crayfish and chironomid species were dominant food items identified from white sturgeon stomachs in

the middle Snake River. This may explain the high density of juvenile white sturgeon in the upper section of Lower Granite reservoir

relative to lower areas of the reservoir. Highest densities of crayfish in Lower Granite reservoir, a prey item of white sturgeon greater

than 17.7 inches (45 cm) long (Scott and Crossman, 1973), occurred near the upper end of the reservoir, which coincided with the

highest densities of juvenile white sturgeon. Bennett et al. (1990) reported high abundance of larval fishes above RM 127.2, which

also may contribute to food resources available to white sturgeon. Lepla’s (1994) sampling in 1990-1991 show that the upriver

portion of Lower Granite reservoir is the most critical portion of the reservoir for juvenile white sturgeon rearing.

Benthic macroinvertebrates that are commonly consumed by salmonids in the lower Snake River and McNary reservoirs also seem

to be largely taxa that are commonly associated with hard substrates. Nightingale (1999) reported differences in the

macroinvertebrate fauna of hard versus soft substrates in the lower Snake River and McNary reservoirs. Several taxa of aquatic

organisms commonly found in the stomachs of juvenile anadromous salmonids in Lower Granite reservoir were from organisms

produced on firm substrates (Karchesky, 1996). Hard substrata in the lower Snake River and McNary reservoirs occur alo ng riprap

(Nightingale, 1999) and the original river channel. Some of these organisms "drift" in the upstream portion the reservoirs primarily in

the seasons of higher flow that increases their availability to rearing and downstream migrating juvenile salmonids and resident

fishes.

Chipps et al. (1997) showed that construction of shallow-water habitat with dredged material has increased habitat complexity in

Lower Granite reservoir and proper placement has potential as an enhancement technique. Chipps et al. (1997) concluded that

islands constructed from dredged material altered the "natural" reservoir habitat by decreasing depth and, therefore, improving

rearing habitat for several resident fishes.

3.1.3 Aquatic and Terrestrial Plants

Aquatic plants within the study area include phytoplankton, algae, and various macrophytes. Each of these plant types is an

important component to overall flora production within the reservoirs.

Phytoplankton presence in the Snake and Columbia rivers has been typically measured by sampling for monochromatic chlorophyll

a. Ledgerwood et al., 2000, reported peaks in concentrations of chlorophyll a primarily in April before peak flows occurred in Lower

Granite reservoir and again in the periods of the declining hydrograph from July until approximately October (depending on location

of sampling in the reservoir and year). Gilbreath et al. (2000) reported similar patterns of chlorophyll a prevalence for John Day

reservoir during the same time periods of 1994 and 1995.

Filamentous green algae was described as part of the diet for several of the fish species in the Little Goose reservoir, but was not

prominent in any diet (Bennett et al., 1983). Filamentous green algae can be found attached to rocks, woody debris, and other

structures.

Macrophytes are large plants that typically grow in shallow water along the shorelines of lakes or in the slow-moving reaches of

rivers. They can be entirely submerged or emergent. Bennett et al. (1995) reported the presence of two species of pondweed in

Lower Granite reservoir including Potamogeton crispus and P. filiformis. Emergent macrophytes are an important element in the

food chain because they provide habitat for insects, which, in turn, can be food for fish, and they function as direct food source for

many aquatic organisms. They also supply surfaces for fish eggs to incubate as well as protection for fish species during various life

stages. These plants are especially important for young fish that hide among plant stems and leaves to escape predators.

Macrophytes help stabilize shorelines by reducing erosion and recycling nutrients.

Terrestrial plants growing adjacent to the reservoirs can contribute woody debris, leaf litter, and other organic debris that can be

utilized as cover, substrate, and nutrients by invertebrate and vertebrate aquatic fauna if it falls into the water. Terrestrial plants

generally do not contribute directly to fish diets. See section 3.2 for further discussion of the terrestrial ecology of the project area.

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3.1.4 Fish Predation

The most important fish-eating fish species include smallmouth bass, northern pike minnow, channel catfish, crappies, and yellow

perch. Of particular importance, the larger individuals may seasonally forage on juvenile salmonids residing in, or migrating through,

the reservoirs. However, other than juvenile fall chinook salmon, fish predation appears to be relatively low in yearling chinook

salmon and steelhead (Corps, 1999). The most important single predator on juvenile salmonids is smallmouth bass because of their

abundance (Corps, 1999). Predation by northern pike minnow has been substantially reduced in the lower Columbia and Snake

Rivers by the Sport Reward Program and scientific sampling funded by BPA (Corps, 1999), both of which remove significant

numbers of northern pike minnows.

3.2 TERRESTRIAL RESOURCES

3.2.1 Vegetation

The study area along the Columbia and Snake Rivers passes through steppe and shrub-steppe plant communities (Franklin and

Dyrness, 1973; Daubenmire and Daubenmire, 1984). Steppe communities are dominated by bunchgrasses, such as Idaho fescue,

bluebunch wheatgrass, and Sandberg’s bluegrass, while shrub-steppe communities are co-dominated by sagebrushes, such as big

sagebrush. Both the Columbia and Snake Rivers are major migration and dispersal corridors for plants and wildlife and have a high

degree of local variation (Franklin and Dyrness, 1973).

Prior to the construction of the dams and impoundments, rich alluvial soils associated with the floodplains allowed the development

of quality riparian vegetation along the rivers. Over 50 vegetated islands were present in the Snake River alone with numerous sand

and gravel bars common (Technical Appendix M, Corps, 1999).

The construction of the dams and impoundments reduced the native upland and riparian habitats within the study area. Emergent

wetland habitat increased significantly after construction of the dams and impoundments due to sedimentation and flooding of

backwater areas.

The project reservoirs have influenced the extent and distribution of numerous plant and wildlife communities that have existed

within the river corridor for many years. Local plant communities have established under normal reservoir fluctuations and periodic

drought. Specifically, riparian, wetland, and shallow-water habitats on the Columbia and Snake Rivers have established under

normal, daily reservoir fluctuations of 3 to 5 feet (0.9 to 1.5 m). The following discussion is limited primarily to the major plant and

wildlife associations within the project reservoirs, including riparian, wetland, upland, and HMUs.

3.2.1.1 Riparian Communities

The riparian zone includes areas with woody vegetation that are too dry to be considered wetlands, sand and gravel bars, wet

meadows, flood-scoured areas, and other stream-related habitats and vegetation. Riparian areas serve as important wildlife habitat

and are integral to the function of river aquatic ecosystems, wind shelters for residences, and locations for recreational activities

(Corps, 1999).

Currently, approximately 1,804 acres (730.1 hectares) of similar habitat exists in varying proportions along the lower Snake River

reservoirs (Corps, 1999). Approximately 2,908 acres (1 176.8 hectares) of riparian communities occur alo ng the McNary reservoir

(Corps, 1992).

In general, riparian forests on the lower Snake River are dominated primarily by Russian olive (Elaeagnus angustifolia), but also

include black cottonwood (Populus trichocarpa), black locust (Robinia pseudo-acacia), hackberry (Celtis reticulata), and white alder

(Alnus rhombifolia). Scrub-shrub vegetation includes coyote willow (S. argophylla), other willows (Salix spp.), and false indigo

(Amorpha sp.). Herbaceous plants in this area include dotted smartweed (Polygonum punctatum), cocklebur (Xanthium sp.), thistle

(Carduus sp.), and mustard (Brassica sp.). A few large sandbars and islands occur along the river that also support plant

communities typically dominated by licorice root (Glycyrrhiza lepidota), cocklebur, and willows.

Riparian vegetation is abundant along the McNary reservoir in the Columbia River. This is an extremely diverse area consisting of

numerous islands, shallow-water and backwater areas, riparian forests, and wetlands. Deciduous riparian trees in this area are

some of the largest in the region. In general, deciduous riparian trees associated with the projects are characterized by (in order of

abundance) Russian olive, willows, and black cottonwood. Riparian shrubs include willows, dogwood (Cornus sp.), and rose (Rosa

sp.). Riparian herbs include a mixture of various forbs and grasses that occupy sand, mud, and gravel bars in the reservoir areas

(Asherin and Claar, 1976; Tabor, 1976).

A number of factors contribute to the lack of extensive riparian areas along the lower Snake River and Columbia River (Corps, 1992;

Corps, 1999). The steep shorelines associated with project reservoirs are primarily responsible for limiting development of riparian

communities in the study area. Furthermore, ext ensive grazing (Lewke and Buss, 1977), the expansion of railroads, and the

gradual inundation of the river bottom by dams have also limited riparian vegetation to narrow vegetation corridors and backwater

areas. The woody plant community that remains in the study area is drought resistant and composed of black locust, Russian olive,

and various hybrid cherries (Prunus sp.) (Asherin and Claar, 1976).

Since 1976, much of the shoreline has been fenced to limit cattle grazing to selected cattle watering corridors along the lower Snake

River. Much of the existing vegetation has rebounded with the removal of cattle grazing. However, cattle watering corridors do still

exist.

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3.2.1.2 Wetland Communities

Wetlands along the river and inside stream deltas serve a variety of physical and biological functions including wildlife habitat

(waterfowl, big game, furbearers, etc.); fish breeding and foraging habitat; nutrient/sediment trapping; flood control; and recreation.

The amount of wetlands has increased on the Snake River from less than 10 acres (4.0 hectares) in 1958 to over 350 acres (141.6

hectares) today (Corps, 1999). In the McNary reservoir, there are over 1,010 acres (408.7 hectares) of wetlands (Corps, 1992).

Wetlands along the lower Snake River reservoirs are characterized by emergent plant communities. Cattails (Typhus latifola) and

bulrush (Scirpus sp.) are the predominant wetland plants along the reservoirs.

Wetlands associated with the McNary reservoir are also of the emergent variety. Extensive wetlands occur in the McNary reservoir

near the mouths of the Walla Walla, Snake, and Yakima Rivers. Typical native vegetation includes cattails, bulrush, willows, and

black cottonwood. Exotic species include purple loosestrife and false indigo.

On the Snake River, numerous small pockets of wetlands and ponds exist in small impoundments behind roads and railroads along

the reservoirs and other embayments. Vegetation is dominated by cattails and softstem bulrush, with some rushes and sedges.

Purple loosestrife and false indigo are found in these areas. The increase in these types of communities is due to several factors: (1)

abundant slack water, which causes sediments carried into reservoirs to accumulate and create good conditions for wetland

vegetation development; (2) several embayments and backwaters that allow for wetland development; (3) drawdowns that allowed

wetland vegetation to establish; and (4) runoff and seeps from nearby irrigated HMUs (Corps, 1999).

3.2.1.3 The HMUs

The HMUs are lands designated primarily for management as wildlife habitat. These areas provide essential habitat for numerous

plants and wildlife of the lower Columbia/Snake River system and have been developed or have established naturally under

prolonged periods of normal reservoir conditions. Sixty-two HMUs have been designated along the lower Snake River (Corps, 1999).

Approximately 760 acres (307.6 hectares) of irrigated lands are associated with the 11 intensively managed (i.e., irrigated) HMUs on

the four lower Snake River projects (Sather-Blair et al., 1991). The largest HMU, Big Flat at 850 acres (344.0 hectares) (Sather-Blair

et al., 1991), is located 3 miles (4.8 km) upstream of Ice Harbor Dam. Irrigated HMUs at each of the reservoirs have been planted

extens ively with trees and shrubs along reservoir shorelines and with herbaceous plants to establish feeding areas for wildlife.

Numerous dryland (non- irrigated) HMUs are located along each of the lower Snake River reservoirs. Dryland HMUs have limited

development that may include guzzlers (water-trapping structure for wildlife), quail roosts, and brush piles. The Joso site is a

dryland HMU encompassing about 568 acres (229.9 hectares). The center of this HMU is a large gravel quarry that was excavated

during the relocation of the railroads prior to the filling of Lower Monumental reservoir. The habitat surrounding the gravel quarry is

shrub-steppe. Four guzzlers and two brush piles have been constructed on the HMU.

McNary reservoir has several wildlife management areas. Five HMUs, totaling 4,500 acres (1 821.1 hectares), are managed by the

Corps and USFWS. The 500-acre (202.3-hectare) McNary Wildlife Nature Area is located just downstream of McNary Dam and is

also managed by the Corps. The 3,600-acre (1 456.9-hectare) McNary National Wildlife Refuge (NWR) is managed by the USFWS

near the confluence of the Snake and Columbia Rivers. This refuge has recently been expanded to include the Corps-owned lands

(mentioned above) under lease to the USFWS.

3.2.2 Wildlife

The project reservoirs provide essential habitat for numerous birds, reptiles, amphibians, small mammals, bats, and big game

animals (Asherin and Claar, 1976, Tabor, 1976). Asherin and Claar (1976) identified 87 species of mammals and 257 species of

birds that occur in the vicinity of the lower Snake River and McNary reservoirs. They generally are dependent on tree-shrub riparian

habitat associated with the project reservoirs (Lewke and Buss, 1977). In general, riparian and wetland areas support higher

population densities and species numbers than dryland shrub-steppe, talus, cliff, and/or grassland habitat, which are also prevalent

along the project reservoirs. Habitats associated with the river generally support trees or dense grass- forb cover that provide more

structurally complex areas and more abundant forage resources than adjacent uplands.

Inundation of the lower Snake and Mid-Columbia Rivers following dam construction between the early 1950's and 1975 eliminated

nearly all of the woody riparian habitat present. Since inundation, the shorelines with adequate hydrology have reestablished a

portion of this riparian community. Due to the lack of suitable hydrology and land management practices of the time, the riparian

habitat is now highly discontinuous and dominated by exotic species such as Russian olive. Additional riparian habitats have been

developed through the establishment of intensive HMUs. Thus, wildlife generally associated with wildlife habitats tends to be

concentrated in these HMUs and in the natural vegetation along the major tributaries, such as the Tucannon, Palouse, and Walla

Walla Rivers.

The project reservoirs provide food, water, and cover for numerous wildlife species and are especially important in the Clearwater

River, lower Snake River, and McNary reservoir where moisture is extremely limited. Wildlife that typically uses riparian and wetland

habitat area associated with the project areas can be divided into nine main groups: waterfowl, upland game birds, raptors, small

mammals, other non- game birds, big game animals, furbearers, amphibians and reptiles, and listed threatened and endangered

species (Asherin and Claar, 1976; Tabor, 1976).

3.2.2.1 Waterfowl

Over 30 species of waterfowl have been documented to occur on the Columbia and Snake Rivers in the project area (Lewke and

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Buss, 1977: Asherin and Claar, 1976; Rocklage and Ratti, 1998). Resident, breeding waterfowl numbers are generally low except for

Canada geese (Branta canadensis), mallard (Anas platyrhynchos), Barrow’s goldeneye (Bucephala islandica), and American

widgeon (Anas americana), which occur throughout the projects. Waterfowl nesting is limited within the lower Snake River reservoirs

because of shortage of suitable nesting habitat. Nesting habitat is more readily available adjacent to the McNary reservoir.

Of the four lower Snake River reservoirs, Ice Harbor reservoir typically has the most waterfowl (mainly mallard and Canada geese)

during migration and winter with a high count of almost 16,000 mallards in December, 1978 (unpublished aerial waterfowl counts by

the USFWS and WDFW). This may be a result of the Ice Harbor reservoir being a waterfowl reserve where waterfowl hunting is

prohibited. While waterfowl numbers drop off upstream, the diversity of waterfowl increases (USFWS, 1999a).

The McNary reservoir supports a large population of nesting Canada geese. The 25-plus islands, together with the McNary NWR

and HMUs, annually produce up to 600 to 700 goslings and provide habitat for nesting ducks, primarily mallards. Most goose

nesting occurs on seven islands, with the greatest numbers of successful goose nests on Badger Island.

Canada goose nesting on the lower Snake River and in McNary reservoirs occurs primarily on reservoir islands and along cliffs.

Surveys conducted between 1974 and 1987 in the project vicinity have found that over 80 percent of Canada goose production was

supported on Badger, Foundation, and New York Islands, producing 280 nests (Boe, 1988). Island nesting on the lower Snake

River produced about 125 nests in 1996 (Corps, 1999).

3.2.2.2 Game Birds

The major game bird species occurring in the study area include ring- necked pheasant, California quail, chukar, and mourning

dove of which only the mourning dove is native (Asherin and Claar, 1976; Rocklage and Ratti, 1998). These game birds are relatively

common throughout the study area, extending from riverside to the upland areas.

Ring-necked pheasants depend on permanent shrub and tall herbaceous cover that is maintained on irrigated lands in the study

area. They are often found on irrigated HMUs foraging on food plots (Corps, 1999).

Chukars use a wide variety of habitats. Oelklaus (1976) found that chukars use Douglas hackberry, smooth sumac, and poison ivy

stands along the project area. Shrub and talus areas are important for nesting (USFWS, 1995). Cheatgrass and agricultural grains

are important for foraging (Gilbreath and Moreland, 1953; Christensen, 1970).

Of all the game species inhabiting the project area, California quail were most adversely affected by inundation of the dams.

Pre-project habitat conditions were ideal for California quail (Sather-Blair et al., 1991) with good interspersion of cropland (food) and

riparian vegetation that provided important escape and winter cover. Since completion of the projects, the percentage of project area

in food-producing cover types (e.g., agricultural crops) has decreased, and the distances between food and cover have increased.

3.2.2.3 Raptors

Riparian forests and wetlands along the Snake, Columbia, and Clearwater rivers provide perching and nesting opportunities, and

concentrated prey (e.g., small mammals, songbirds) (Tabor, 1976; Asherin and Claar, 1976; Asherin and Orme, 1978). In general,

cliffs and large trees along riverbanks typically support diverse raptor populations. The McNary and lower Snake River reservoirs

provide cliff areas in proximity to the rivers that may provide potential nest and roost sites for bald eagles (Haliaeetus

leucocephalus), golden eagles (Aquila chrysaetos), and prairie falcons (Falco mexicanus) (Payne et al., 1975; Asherin and Claar,

1976; Tabor, 1976).

Rocklage and Ratti (1998) documented 17 species of raptors in the study area. Asherin and Claar (1976) found only 13 species

within the same area, with one species (burrowing owl) not seen in the previous study. During the summer of 1981, Fleming (1981)

found a total of 172 raptor nests of 10 species along the Snake River from Lewiston, Idaho, to Ice Harbor. Although nesting

information was not specifically recorded, Rocklage and Ratti (1998) recorded 209 raptors of 12 species present along the lower

Snake River during the breeding season. Asherin and Claar (1976) found American kestrel (Falco sparverius) and red-tailed hawk

(Buteo jamaicensis) to be the most common raptors in the lower Snake River area.

Peregrine falcons (Falco peregrinus) were recently removed from the endangered species list. There are no reported peregrine

falcon nests in or near the dredging or dredged material disposal sites. An active aerie is located along Weissenfels Ridge near the

confluence of the Snake River and Tenmile Creek, approximately 8 miles (12.9 km) south of Clarkston (USFWS, 1999a). Peregrine

falcons could potentially travel through this area during migrations.

Bald eagles are found in the study area usually during the winter, between November and March. A few bald eagles winter along

the McNary reservoir (BPA et al., 1994). Mid-winter bald eagle surveys reported 10 eagles on the lower Snake River (Corps, 1999).

One nesting attempt was recorded on the Strawberry Islands, near the mouth of the Snake River in 2000. This nest was

unsuccessful. Eagles feed primarily on waterfowl and fish, which are present in the reservoirs. Bald eagles are discussed further in

section 3.3.2.1.

3.2.2.4 Non-Game Birds

The project reservoirs provide essential habitat for numerous colonial nesting birds, shorebirds and songbirds (Asherin and Claar,

1976, Tabor, 1976). They generally are dependent on tree-shrub riparian habitat associated with the project reservoirs (Lewke and

Buss, 1977). In general, riparian and wetland areas support higher population densities and species numbers than dryland shrubsteppe, talus, cliff, and/or grassland habitat, which are also prevalent along the project reservoirs. Habitats associated with the river

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generally support trees or dense grass-forb cover that provides more structurally complex areas and more abundant forage

resources than adjacent uplands.

There is some evidence that bird species richness along the project area has declined from pre-impoundment conditions. Of 61 total

bird species found by Dumas (1950), 12 were not reported by a more recent study (Rocklage and Ratti, 1998). These species

include the black-chinned hummingbird, veery, red-eyed vireo, solitary vireo, American redstart, Brewer’s blackbird, and fox sparrow.

Most of these species are associated with riparian forest habitat (Smith et al., 1997). These species are still seen in and around the

lower Snake River by the local chapters of the Audubon Society. The redstart, vireos and brewers blackbird are seen very rarely and

may have been migrants in previous studies. It has been documented that conversion of native riparian forest to exotic species such

as Russian olive, have reduced species diversity in the region, especially for insectivorous birds (USFWS, 1997).

Rocklage and Ratti (1998) observed a total of 92 bird species during the breeding season within the study area. Within the various

habitats along the rivers, the HMUs had higher bird species richness during both the breeding season and the fall than the woody

drainages leading into the reservoirs. Their narrow width and their degradation may limit the suitability of the woody drainages for

foraging and nesting. Therefore, despite the lack of mature riparian habitat on the HMUs, they still provide important habitat for

riparian bird species.

California gulls (Larus atricilla), ring-billed gulls (L. delawarensis), Forster’s terns (Sterna forsteri), Caspian terns (S. caspia), and

double crested cormorants (Phalacrocorax auritus) nest in large concentrations on the lower Columbia River, particularly on

Crescent and Foundation Islands along the McNary reservoir. Pied-billed grebes (Podilymbus podiceps) and rail species use many

of the backwater areas throughout the project area. Killdeer (Charadrius vociferus) and spotted sandpiper (Actitis macularia) nest

and forage just upslope from the high reservoir line and along the shoreline throughout the project area. In addition, over 1,000

white pelicans (Pelicanus erythrorhynchos) typically occur along the Columbia River between Boardman, Oregon, to Vernita Bridge,

north of Richland, Washington (Corps, 1992).

3.2.2.5 Small Mammals

Eleven small mammal species have been observed in the study area, with two additional species likely present (Corps, 1999).

These species include deer mouse, western harvest mouse, Great Basin pocket mouse, house mouse, long-tailed vole, montane

vole, northern pocket gopher, vagrant shrew, Merriam’s shrew, bushy-tailed woodrat, and Ord’s kangaroo rat (Rocklage and Ratti,

1998; Johnson and Cassidy, 1997; Asherin and Claar, 1976). Deer mice make up the majority of individuals found in the project

area. Rocklage and Ratti (1998) found six species, with deer mouse composing 74 percent of total captures. Notably, some

evidence suggests that small mammals prefer native riparian habitat to other habitat. Asherin and Claar (1976) found the highest

species diversity in their study in the native cattail and shrub willow habitat types. Six species of bats have been documented in the

study area and five more are suspected to occur based on habitat suitability, their range, and their occurrence in the vicinity

(Johnson and Cassidy, 1997; Mack et al., 1994; Asherin and Claar, 1976). Documented species include Yuma myotis, western

pipistrelle, pallid bat, small- footed myotis, California myotis, and Townsend’s big-eared bat (Asherin and Claar, 1976; Johnson and

Cassidy, 1997). Other species of bats that may also be present include long- legged myotis; long-eared myotis; fringed myotis;

hoary bat, and big brown bat (Johnson and Cassidy, 1997; Asherin and Claar, 1976).

3.2.2.6 Furbearers

Aquatic furbearers occur in each of the project reservoirs and include muskrat (Ondatra zibethicus), beaver (Castor canadensis),

river otter (Lutra canadensis), and mink (Mustela vison). In general, this group is dependent on riverine areas, embayments, ponds,

tributaries, and riparian forests for den sites and foraging areas. Beaver distribution within the project reservoirs is strongly

associated with the presence of cottonwood and protected areas. (Asherin and Claar, 1976). Muskrats are particularly abundant in

embayments and sloughs where aquatic plants are also abundant. Mink and river otter use the project reservoirs, ponds, sloughs,

and backwater areas for foraging and denning. Both the mink and river otter use riprap areas along the banks as den sites

(Sather-Blair et al., 1991).

Asherin and Claar (1976) observed four species of terrestrial furbearers: bobcat, coyote, raccoon, and striped skunk and the three

species of aquatic furbearers discussed above. They concluded that aquatic furbearer abundance was low along the lower Snake

River. Asherin and Claar (1976) also noted that that the aquatic furbearers were more abundant in those study segments with more

extensive riparian habitat such as the McNary NWR.

Although it is likely that some of these species were never abundant (Asherin and Claar, 1976), inundation by the reservoirs

probably eliminated much of the riparian habitat that was important for foraging and denning for many of the furbearers. In

particular, muskrat and mink seem to have declined (WDG, 1984; Corps, 1999). When comparing habitat value for river otter both

pre-project, lower Snake River, and conditions today, habitat values meet or exceed those values for pre-project conditions. This is

mainly due to the shoreline structure developed by riprap and woody exotic vegetation. It is not clear whether this has translated

into higher otter numbers since surveys for otters have not been conducted in recent years.

3.2.2.7 Big Game Mammals

Mule and whitetail deer are the most common big game inhabiting the study area (Tabor, 1976). Mule deer make up about 80

percent of the deer population with the whitetail deer making up the remaining 20 percent. Populations of deer have recovered to

pre-impoundment carrying capacity (Corps, 1990). This increase is at least partly due to the development of habitat in HMUs and

the exclusion of livestock from much of the study area (Corps, 1999).

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Suitable habitat for deer in the study area mainly serves as wintering range, with the deer making seasonal and daily migrations out

of the canyons to forage in the surrounding cultivated land. Deer use a wide variety of habitats including shrub and brush for cover

and fawning and grassland for foraging.

Mule deer are found in increasing numbers from the Lower Monumental reservoir upstream to the upper half of the Little Goose

reservoir (Tabor, 1976). There is some evidence that greater precipitation and higher habitat diversity along the upper two lower

Snake River reservoirs provide more stability for deer populations than habitats downstream and extending into the McNary reservoir

(Corps, 1990).

Other species that have been observed along the river but that are considered uncommon include elk, bighorn sheep, black bear,

moose, and mountain lion (Corps, 1999).

3.2.2.8 Amphibians and Reptiles

Sixteen species of amphibians and reptiles have been documented in the study area (Asherin and Claar, 1976; Loper and

Lohmann, 1998; McKern, 1976). The most commonly occurring species were the Pacific tree frog (Hyla regilla), bullfrog (Rana

catesbeiana), western yellow-bellied racer (Coluber constrictor mormon), Great Basin gopher snake (Pituophis melanoleucus

deserticola), long-toed salamander (Ambystoma macrodactylum), western toad (Bufo boreas), night snake (Hypsiglena torquata),

western rattlesnake (Crotalus viridis), and painted turtles (Chrysemys picta). Other species that may occur within the study area, but

were not observed by Asherin and Claar (1976) or Loper and Lohmann (1998) include: the tiger salamander (Ambystoma tigrinum),

northern leopard frog (Rana pipiens), short-horned lizard (Phrynosoma douglassi), sagebrush lizard (Sceloporus occidentalis),

rubber boa (Charina bottae), and the ringneck snake (Diadophis punctatus).

Of the vegetation types sampled by Asherin and Claar (1976), the ones most closely associated with water had the greatest relative

abundance of amphibians. In particular, native willow and emergent wetland habitats have the greatest species diversity. In general

Loper and Lohmann (1998) found that species richness and abundance were low at both riparian and upland locations. Some of the

reasons may include the relatively young age of the recovering riparian fringe beside the existing reservoirs; the isolation of suitable

riparian habitat into discrete patches along the river (i.e., HMUs); and fluctuating water levels in the reservoirs that prevent the

consistent occurrence of litter, debris, pools, and vegetation that these species could use for breeding, resting, and forage (Loper

and Lohmann, 1998).

3.3 ENDANGERED SPECIES

The ESA establishes a national program for the conservation of threatened and endangered species of fish, wildlife, and plants and

the preservation of the ecosystems on which they rely. Section 7 of the ESA requires Federal agencies to consult with the USFWS

and/or NMFS as necessary to ensure that their actions are not likely to jeopardize the continued existence of endangered or

threatened species or adversely modify or destroy critical habitat. It also requires that Federal agencies prepare BA's of the potential

effects of major construction actions on listed species.

Several species listed as threatened or endangered under the ESA are potentially found in the lower Snake River reservoirs and

McNary reservoir. The following sections describe these species and their use of the study area. Additional information regarding the

presence of these species in the study area and the impacts of the proposed dredging and dredged material disposal are found in

the BA’s (appendix F and appendix G) prepared by the Corps. Full documentation of these consultations is presented in Appendix F (for

NMFS) and Appendix G (for USFWS).

3.3.1 Fish

3.3.1.1 Anadromous Fish

The existing anadromous fish species and environmental conditions in the study area that could be affected by the alternatives in

this DMMP/EIS are discussed in detail in section 3.1.1.1. However, the NMFS has determined that the effects of the proposed actions

will not jeopardize the continued existence of endangered SR sockeye, threatened SRF chinook, threatened SRSS chinook,

threatened SRB steelhead, endangered UCRS chinook, endangered UCR steelhead, or threatened MCR steelhead or result in the

adverse modification or destruction of their Critical Habitat. The determination of no jeopardy is based upon the current status of the

species, the environmental baseline for the action area, and the effects of the proposed actions. Other potentially impacted species

such as Pacific lamprey are also discussed in section 3.1.1.1.5.

3.3.1.2 Resident Fish

The only subpopulations of bull trout associated with the four lower Snake River reservoirs spawn and rear in the Tucannon River

Basin. Both resident and migratory forms occur there. A detailed discussion on bull trout is presented in section 3.1.1.2.3. Margined

Sculpin is a species of concern and is discussed in section 3.1.1.2.5.

3.3.2 Wildlife

There is one listed wildlife species that may occur in the project area (USFWS, 2000), the bald eagle. Washington ground squirrel is

currently a candidate species for listing. In addition to the listed species, a discussion of species of concern is presented in section

3.3.4.

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3.3.2.1 Bald Eagle - Threatened

Bald eagles are usually associated with a source of permanent water, such as reservoirs, lakes and free-flowing rivers, with

abundant fish and nearby sites for perching, roosting, and, in season, nesting. Their primary prey is fish, especially salmon, but

they also eat small mammals, various water birds, such as waterfowl, and carrion. In the winter, provided the roosting sites and food

are abundant, eagles roost in groups, particularly in conifer stands or along rivers with migrating salmon.

In the western United States, eagles reside along the western coast from southern Alaska through the Pacific Northwest to northern

California. In the winter, bald eagles can be found throughout most of the United States west of the Mississippi River. In

Washington, bald eagles nest along the Pacific Ocean, Puget Sound, large lakes, and rivers. They winter along rivers that support

large runs of anadromous fish, the Puget Sound, and the Pacific Ocean.

During the nesting season (February 1 through August 15), bald eagles use breeding habitat close to rivers, lakes, marshes, or

other food sources. Important habitat components include nest trees, perch trees, and available prey. Live, mature trees with

deformed tops are often selected for nesting, and nests are often reused year after year. Snags, trees with exposed lateral

branches, or trees with dead tops are important for perch-sites while hunting or defending territories. Perches used for foraging are

normally close to water where fish, waterfowl, seabirds, and other prey can be captured.

Wintering bald eagles (November 1 through March 15) congregate along rivers, lakes, and streams, where winter runs of salmon

provide an abundant prey base. Waterfowl concentrations may also be important winter food sources. In eastern Washington, mixed

stands of black locust and black cottonwood provide important roosting and perching habitat.

There are no documented successful bald eagle nests in or around the project area. An unsuccessful nesting attempt occurred on

Strawberry Island near the mouth of the Snake River during the 2000 nesting season. This site is adjacent to proposed dredging

activity for the approach to Ice Harbor. Bald eagles have also attempted nesting in the Clearwater and Grande Ronde drainages and

at the Hanford Reservation north of Richland, Washington. These sites are well over a mile (1.6 km) from the project area. The

limited amount of suitable habitat makes additional nesting in the project area unlikely.

Based on data from Corps mid-winter surveys, bald eagles may be present in the project area during the winter, roosting in black

locust or black cottonwood trees where available. Mid-winter censuses have been conducted on the lower Snake and Columbia

Rivers from McNary (on the Columbia below the confluence with the Snake) to Asotin, Washington, [2 miles (3.2 km) upriver from

Clarkston, Washington] annually since 1989. These surveys generally take place in January and are divided into two survey areas.

The Western Project survey area extends from McNary to Lower Monumental. The Eastern Project area extends from Lower

Monumental to the upper influence of the Lower Granite reservoir, near Asotin, Washington. Surveys were typically conducted in

January and were confined to Corps- managed lands along the rivers.

The last 5 years of survey results were examined to determine average annual bald eagle occurrence. In the Western Project area,

bald eagle counts ranged from 11 to 19 individual birds annually. Many of the locations are less than 1 mile (1.6 km) from proposed

dredging and dredge disposal activities. These include Strawberry Island below Ice Harbor, Sacajawea Park at the Snake and

Columbia Rivers confluence, and Big Flat HMU above Ice Harbor. In the Eastern Project area, between three and five individual bald

eagles per year have been counted. One or two of these are usually found in the Snake/Clearwater Rivers confluence area, near

the proposed Lower Granite dredging and levee-raising activities.

3.3.2.2 Washington Ground Squirrel - Candidate

These squirrels are found in steppe and open shrub-steppe, where they prefer deep, loose soil for digging burrows. One existing

colony in Walla Walla County is within the study area, while five additional colonies are located nearby. Use of the Joso site for

upland disposal of dredged material has the potential to negatively impact Washington ground squirrels during disposal operations

through disturbance of habitat. Most of the ground to be disturbed is within the gravel pit, where soils are less suitable for ground

squirrels. Most suitable habitat will remain undisturbed. Re storation of grassland habitat after disposal may benefit ground

squirrels.

3.3.3 Plants

One plant species with Federal status may potentially occur in the project area: Ute ladies’ tresses. Also, Spalding's silene is

proposed to be listed and White Bluffs bladder-pod is a candidate for listing.

3.3.3.1 Ute Ladies’ Tresses (Spiranthes diluvialis) - Threatened

This orchid is a lowland species, typically occurring beside or near moderate gradient, medium to large streams and rivers in the

transition zone between mountains and plains. It is not found in steep mountainous parts of the watershed nor along slow

meandering streams out in the flats. The communities where it is often found tend to be typical of riparian habitat in the area. The

species tend to occupy graminoid (grasses, rushes, and sedges) dominated openings in shrubby areas. It occasionally occurs in

spring- fed wetlands in broad valleys isolated from watercourses. Soil moisture must be at or near the surface throughout the

growing season. The species tolerates periodic flooding, but does not occupy constantly inundated areas (USFWS, 1998).

Ute ladies’ tresses occur in a variety of settings, including floodplains, moist to wet meadows on floodplains, abandoned meander

channels, moist to wet meadows irrigated by freshwater springs, riparian streambanks, borrow pits, upper edges of riverbanks,

islands, point bars, and various topographic positions up to 200 feet (61.0 m) horizontally and 0.5 to 4 feet (0.2 to 1.2 m) vertically

from the water’s edge, but not on steep slopes (USFWS, 1998).

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Ute ladies’ tresses were discovered in northern Washington (the Okanogan River valley) for the first time in 1997. They were also

found in the Snake River Basin in southeastern Idaho in 1996. It is now known to be present in northern Washington, southern

Idaho, and nearby parts of Montana. The USFWS has determined that, in the absence of adequate surveys, this species may be

expected to occur in suitable habitat throughout Idaho and Washington (USFWS, 1998).

3.3.3.2 Water howellia (Howellia aquatilis) – Threatened

howellia grows in firm consolidated clay and organic sediments that occur in wetlands associated with ephemeral glacial pothole

ponds and former river oxbows (Shelly and Moseley, 1988; Lesica, 1992). These wetland habitats are filled by spring rains and

snowmelt run-off; and depending on temperature and prescription, exhibit some drying during the growing season. This plant’s

microhabitats include shallow water, and the edges of deep ponds tha t are partially surrounded by deciduous trees (Shelly and

Moseley, 1988; Gamon, 1992).

Only 79 small populations of this aquatic plant were known to exist when the proposed rule to list the species was published (58 FR

19795). Subsequent inventories cond ucted for howellia in the State of Washington located 28 new sites in Spokane County alone,

thus expanding the number of known populations to 107 (Roe and Shelly, 1992; N. Curry, in Litt., 1993; J. Gamon, Washington

Natural Heritage Program in litt., 1993; R. Moseley, Idaho Conservation Data Center, in Litt., 1993). howellia appears to be extirpated

from California and Oregon, from Mason and Thurston Counties in Washington, and Kootenai County in Idaho (Jokerst, 1980;

Shelly and Moseley, 1988; Oregon Natural Heritage Program, 1991; Gamon, 1992).

Nearly all of the remaining populations of howellia are clustered in two main population centers or metapopulations. Within these

areas, individual populations occur primarily in clusters of closely adjacent ponds, although some ponds within the range of these

metapopulations are unoccupied. One metapopulation near Spokane, Washington, consists of 46 individual populations in Spokane

County, Washington, and one in Latah County, Idaho. A second metapopulation is found in the drainage of the swam river in

northwestern Montana (Lake and Missoula Counties, where 59 individual populations are found. In addition to metapopulations, a

third site near Vancouver in southwestern Washington (Clark County) contains two populations that are in close proximity of each

other (Gamon, 1992).

Water howellia is not documented in Idaho near the study area (Idaho Conservation Data Center, 2000). The study area itself does

not exhibit any habitat which could be used by this species.

3.3.3.3 Spalding's Silene - Proposed

Spalding's silene is a plant that has white flowers and is found in virgin Idaho fescue (Festuca idahoensis) habitat types in the

Palouse region (Washington Natural Heritage Program, 1981). Although not documented within the study area, this species has

been found in Whitman and Asotin counties.

3.3.3.4 White Bluffs Bladder-pod - Candidate

A perennial, grayish-pubescent herb of the mustard family that has a well-developed taproot, a dense, many- leaved rosette of

gradually reduced leaves, and dense inflorescences of yellow flowers.

This narrow endemic species is restricted to a very small area in Franklin County adjacent to the Columbia River in south-central

Washington. It is currently known from an area of a few yards (meters) wide by approximately 10 miles (17 km) long.

The species is restricted to a very small area along the Columbia River in shrub steppe vegetation. The species is restricted to dry,

barren, nearly vertical exposures of calcium carbonate paleosol (a "caliche" soil). The substrate is extremely alkaline and highly

calcareous. Elevation ranges between 780 and 890 feet. Associated species include big sagebrush, buckwheat milkvetch, slender

buckwheat, Snake River cryptantha, and Sandberg’s bluegrass. The range of this species is within the driest region in the state of

Washington; the general area receives an average of about 6 inches (15.2 cm) of precipitation per year. As a result, the overall cover

of vegetation is extremely low. As noted above, the species is restricted to a highly alkaline substrate that most plants find

inhospitable. The species is presumably reliant on periodic exposure of these substrates. (Derived from Washington Rare Vascular

Plants Web Page: www.wa.gov/dnr/htdocs/fr/nhp/refdesk/fguide/htm/fsp_letu.htm)

3.3.4 Species of Concern

The following discussion is cited from appendix G, Biological Assessment for Non-Anadromous Fish and Terrestrial Species.

3.3.4.1 Wildlife

3.3.4.1.1 Black Tern

Black terns are small terns that eat primarily insects and can occur statewide, in or near wetlands and sloughs. They usually nest in

marshy wetlands in June. Black terns are periodically reported by birders in the project area, primarily at the mouth of the Walla

Walla River, and are believed to use the area only during migration (Ackerman, 2001). The project is unlikely to impact black terns.

3.3.4.1.2 California Floater

California floaters are mussels found in unpolluted fresh water, except in small creeks. They prefer lakes and slow streams with

areas less than 6.6 feet (2 m) deep and sandy bottoms. Adults will also live on mud bottoms. Juveniles are parasitic on gills, fins,

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and barbels of host fish. The California floater have been located upstream of Hells Canyon Dam (Idaho Dept. of Fish and Game,

Conservation Database Center GIS Database). Dorband (1980) indicated that this genus was not found in Lower Granite Reservoir

in 1977. It is unlikely this species would occur in the study area.

3.3.4.1.3 Columbia Pebblesnail

Columbia pebblesnails are found in the main channels and free- flowing parts of rivers including the Columbia, Grande Ronde,

Salmon, and Snake Rivers. More recent documentation indicates they are present just above the study area on the lower Snake

River. They are often common at the edges of rapids or immediately downstream of whitewater areas, and they feed on diatoms and

algae. The Columbia pebblesnail have been located upstream of the study area in the Lower Salmon River by Idaho Conservation

Database personnel. Dorband (1980) did not list the genus of this species as present in the Lower Granite Reservoir in 1977. Since

this species has been found in a direct tributary of the Snake River above Lower Granite Reservoir, it is possible a few individuals

could migrate downstream of that point. Water quality would still be a limiting factor, so it would be unlikely to find this species in

the impounded areas of the lower Snake River, so should not be found in the study area.

3.3.4.1.4 Columbia Spotted Frog

Columbia spotted frogs are found in warmwater marshes, overflow wetlands, and bogs with non-woody wetland vegetation. They

are found scattered across most of eastern Washington although they have not been observed in the study area (Ackerman, 2001;

Loper and Lohman, 1998).

3.3.4.1.5 Ferruginous Hawk

These large hawks prefer open plains and brushy open country and avoid forested areas. They nest in trees along streams, bluffs,

rock piles, and artificial structures. Ferruginous hawks feed primarily on ground squirrels, rabbits, and other small mammals. They

are uncommon along the lower Snake River corridor although some suitable nesting habitat may be present.

3.3.4.1.6 Fringed Myotis, Long-Eared Myotis, Long-Legged Myotis, Pale Towns end’s Big-Eared Bat,

Small-Footed Myotis, and Yuma Myotis

They commonly forage near or over water and roost in trees and shrubs (riparian areas along the lower Snake River), rock crevices,

and buildings. However, the small- footed myotis forages along cliffs, rock outcrops, and dry canyons.

Depending on the size of interstitial spaces, bats may use riprap areas for roosting or hibernating (Anderson, 2001).

3.3.4.1.7 Harlequin Duck

Harlequin ducks generally rely on fast, turbulent mountain streams as breeding habitat. They may be present in the study area in

August and September (following the nesting season) although sightings are rare. They winter in coastal areas and, thus, would not

likely be present during the project work window of December 1 through March 31.

3.3.4.1.8 Little Willow Flycatcher

The little willow flycatcher uses open brushy areas, especially scrub-shrub wetlands comprised of willows. Willow flycatchers are

seen along riparian drainages in or near the study area during spring and early summer.

3.3.4.1.9 Loggerhead Shrike

Loggerhead shrikes are robin-sized birds that feed mainly on insects, small birds, and mammals. They would be seen in the area

during the summer breeding season. Preferred habitat includes shrub-steppe and any semi-open area with shrubs, fences,

powerlines, or small trees for perches.

Loggerhead shrikes are currently seen on the Hanford Reservation and adjacent areas during the summer. Most of the study area is

outside of this native shrub-steppe habitat.

3.3.4.1.10 Mountain Quail

Mountain quail are uncommon birds that prefer shrubby/forested areas and are found at lower elevations in the Blue Mountains.

Mountain Quail have been recorded in the mountainous areas of northwestern Idaho by the Idaho Consevation Database personnel.

The study area is primarily degraded shrub-steppe which starts at the foothills of the Idaho mountains and goes into the heart of the

Pasco Basin. There is no suitable habitat for this species within the study area.

3.3.4.1.11 Northern Goshawk

Northern goshawks are large hawks that prefer mature and old-growth forests for nesting and would not nest in the study area.

Observations of goshawks would likely be during migration and winter. They are aerial hunters, flying between trees and under

canopy in search of grouse, smaller birds, and other prey. The northern goshawk is primarily a migrant in the area which has been

seen regularly in and around the study area by local chapters of the Audubon Society.

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3.3.4.1.12 Northern Sagebrush Lizard

Northern sagebrush lizards are primarily shrub-steppe dwellers, but also use bouldered regions and forested slopes. They are

typically ground lizards and rarely climb into shrubs. They prefer fine gravel soils, but are also found on sand y or rocky soil. They

need rock crevices, mammal holes, and similar cover for refuge. Northern sagebrush lizards are currently seen on the Hanford

Reservation and adjacent areas during the summer. Most of the study area is outside of this native shrub-steppe habitat.

3.3.4.1.13 Olive-Sided Flycatcher

Olive-sided flycatchers are birds that seem to prefer mixed and broken forests with wooded streams and some wetland. Their diet

consists entirely of flying insects that they search for from high snags and perches. They nest high in conifer trees. Olive-sided

flycatchers are seen along riparian drainages in or near the study area during spring and early summer.

3.3.4.1.14 Western Burrowing Owl

These owls are generally found in open, broken, or flat areas, including shrub-steppe and agricultural areas. They are seen

regularly in the Tri-Cities, Hanford, and Yakima Range areas (Ackerman, 2001). Opportunistic feeders, they prey primarily on insects

and small mammals, but also on birds, fish, and amphibians when available. They use ground squirrel or other mammal burrows for

shelter and nesting.

Artificial burrows were created at the Joso HMU in the early 1980's. No use by burrowing owls has been documented although no

formal monitoring plan has been implemented.

3.3.4.2 Plants

3.3.4.2.1 Northwest Raspberry

This is a Snake River endemic that is found in the Snake River canyon and adjacent tributaries. It occurs along drainage bottoms

and somewhat moist areas on the adjacent slopes along small tributaries to the Snake River, such as Nisqually John Canyon. It is

known from less than two dozen sites, with some of the historic sites inundated with the construction of Lower Granite (Clegg,

1973). Whether it has become established along the current reservoir shorelines is unknown; however, it has become established

on at least four of the intensive HMUs (Phillips, 1993).

3.3.4.2.2 Jessica’s Aster

This tall perennial species has blue flowers and can be found in association with the northwest raspberry. It is found along

streambanks and open places in the Palouse region and is currently known from only nine populations in Whitman County

(Washington Natural Heritage Program, 1981). None of these populations are found within the study area.

3.3.4.2.3 Broad-Fruit Mariposa

This very showy species has purple flowers and is found along the borders of seasonally wet meadows (Washington Natural

Heritage Program, 1981). Although there is no documented presence within the study area, it has been found in Garfield and

Whitman counties.

3.3.4.2.4 McFarlane's Four O'Clock

McFarlane’s four o’clock is known to occur in three geographically isolated units occupying approximately 163 acres (65.0 hectares)

in Idaho and Oregon. The Snake River unit occupies approximately 25 acres (10.1 hectares) along 6 miles (9.7 km) of Hells Canyon

on the banks and canyonland slopes above the river. This plant is found on steep (50 percent) sandy slopes underlain by talus in

canyonland corridors where the climate is regionally warm and dry with precipitation occurring mostly in a winter-to-spring period

(Robinson, 1996).

There are no reported occurrences of McFarlane’s four o’clock in the project vicinity (Robinson, 1996). This project is not expected to

impact this species.

3.3.4.2.5 Washington Polemonium

A member of the phlox family, this species has white or creamy flowers and has a characteristic skunk smell. Its habitat includes

moist bottomlands and has been found in Whitman County. This species has not been documented in the study area. The species

is tied to wet meadow conditions which could be found in the area, so the species may be found if habitat conditions are suitable.

3.4 RECREATION

The lower Snake and Columbia Rivers provide an important recreational resource for the region. There are numerous recreational

facilities lining the shores of the lower Snake River reservoirs and McNary reservoir on the Columbia River. Recreational facilities and

facility visitation are described in the following sections.

3.4.1 Recreation Facilities and Activities

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There are 68 designated recreation sites located on the shores and adjacent areas of the Columbia and Snake Rivers between

McNary on the Columbia River and the upstream end of the Lower Granite reservoir on the Snake River. These facilities include

wildlife refuges, local and state parks, and marinas, and are managed and operated by the Corps, the USFWS, and local and state

recreation agencies. Table 3-1 summarizes the recreation facilities and primary uses. All the facilities are on Corps property.

Table 3-1

Recreation Facilities in the Lower Snake River and McNary Reservoirs

Reservoir Day-Use Boating Marina Camping State

Lower Granite

Blyton Landing WA

Chief Looking Glass WA

Chief Timothy State Park WA

Chief Timothy Habitat Management Unit WA

Clearwater Park ID

Greenbelt Ramp WA

Gateway Golf Center WA

Gateway Park WA

Granite Lake RV Park WA

Hells Canyon Resort WA

Hells Gate State Park ID

Lewiston Levee Parkway ID

Lower Granite Dam WA

Nisqually John Landing WA

North Lewiston Ramp ID

Offield Landing WA

Southway Ramp ID

Swallows Park WA

Wawawai County Park WA

Wawawai Landing WA

Little Goose

Boyer Park and Marina WA

Central Ferry State Park WA

Illia Dunes WA

Illia Landing WA

Little Goose Dam WA

Little Goose Landing WA

Willow Landing WA

Lower Monumental

Ayer Boat Basin WA

Devils Bench WA

Lower Monumental Dam WA

Lyons Ferry Marina WA

Lyons Ferry State Park WA

Riparia Recreation Area WA

Texas Rapids Recreation Area WA

Ice Harbor

Big Flat Recreation Area WA

Charbonneau Recreation Area WA

Fishhook Park WA

Hollebeke Park WA

Ice Harbor Dam Recreation Area WA

Levey Park WA

Lost Island WA

Matthews Recreational Area WA

Windust Park WA

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McNary

Chiawana Park and Road 54 Park WA

Columbia Park WA

Hat Rock State Park OR

Hood Park WA

Howard Amon Park WA

Hover Park WA

Leslie R. Groves Park WA

Locust Grove/Martindale WA

Madame Dorion Memorial Park WA

McNary Beach Park OR

McNary Dam Visitor Center OR/WA

McNary National Wildlife Refuge WA

McNary Yacht Club OR

Oregon Boat Launch OR

Pacific Salmon Visitor Information Center OR

Pasco Boat Basin WA

Peninsula Habitat Management Unit WA

Sacajawea State Park WA

Sand Station OR

Spillway Park OR

Two Rivers Habitat Management WA

Two Rivers Park WA

Walla Walla Yacht Club WA

Wallula Habitat Management Unit WA

Warehouse Beach OR

Washington Boat Launch WA

West Park OR

Wye Park WA

Source: Walla Walla District Recreation Pages

Recreational activities take place throughout year, with the highest activity levels during the fair-weather periods of late spring,

summer, and early autumn. Due to the setting of recreational facilities, most recreation is related to the water resources presented

by the Snake and Columbia Rivers. Boating, swimming, and fishing are common activities, as are camping and day-use activities

such as picnicking, hiking, and wildlife observation. Water-dependent activities, such as fishing and boating, take place during the

same months that dredging is planned (December through February), however at generally lower activity levels than in spring and

summer months, although steelhead fishing activities are highest in the autumn months. Similarly, the riverfront parks in Lewiston

are used year-round and could be potentially affected by the alternatives that include raising levees.

3.4.2 Facility Use/Visitation Patterns

As noted in section 3.4.1, recreational facilities in the study area are used for a variety of activities throughout the year. Table 3-2

summarizes annual visitation to all facilities within each reservoir. Visitation reflects both the number of facilities, recreational

opportunities, and proximity to large groups of potential users. For instance, because of their proximity to the Tri-Cities (Richland,

Pasco, and Kennewick, Washington) area and the number of facilities they offer, the McNary and Ice Harbor reservoirs’ recreation

facilities have significantly higher levels of visitation than those in the more remote Lower Monumental reservoir.

Table 3-2

Recreation Facility Visitation at Lower Snake River Reservoirs

FY 95 to FY 97

Reservoir

FY 95 FY 96 FY 97

Visitor Hrs Visits Visitor Hrs Visits Visitor Hrs Visits

McNary 11,469,800 4,609,200 11,019,300 4,300,900 10,772,055 4,281,893

Ice Harbor 5,234,800 467,100 5,074,600 473,700 4,650,860 433,843

Lower Monumental 722,300 165,700 815,300 177,900 835,696 172,538

Little Goose 1,436,900 202,100 1,798,400 278,000 1,650,568 245,569

Lower Granite 2,319,800 861,500 3,010,800 1,033,500 3,082,700 1,047,094

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Source: U.S. Army Corps of Engineers, Walla Walla District. McNary Visitation Report 1995-1997

Regarding the riverfront parks in Clarkston and Lewiston that could be potentially affected by the alternatives including raising the

levees, in Fiscal Year 1998 (FY 98) (October 1997 through September 1998) visitation patterns were as follows:

Swallows Park in Clarkston: 682,200 visitor hours

Lewiston Levee Park: 329,100 visitor hours

Chief Looking Glass in Asotin: 69,800 visitor hours

These parks see heavy day use throughout the summer except on very hot days, when the usage is generally in the morning and

late evening. Peak usage for all these areas is summer. Spring, fall, and winter receive light to moderate use that is generally

weather-dependent (Wiedmeier, 1999). Lewiston Levee Park, for example, features a multi- use trail that runs along the levee, as

well as picnic tables and other day use facilities. A levee raise could directly modify the west Lewiston levee.

3.5 CULTURAL RESOURCES

Cultural resources in the DMMP study area (lower Snake River and McNary reservoirs) are a rich source of information about

prehistoric and historic human use and occupation of this area dating back over 10,000 years. Cultural resources can generally be

placed into one of the following three categories: prehistoric, historic, and traditional cultural properties (TCP). The information

provided in this section is primarily derived from the System Operational Review Final Environmental Impact Statement (SOR FEIS)

(BPA et al., 1995) and the current information collected in the development of the Lower Snake River Juvenile Salmon Migration

FR/EIS. For further information see the Feasibility Study main report and Appendix N, Cultural Resources, as these documents are

incorporated by reference.

3.5.1 Cultural Resource Definition

Cultural resources are the material remains of past human life or activities. They can consist of objects, buildings, structures, sites,

or districts (a group of closely associated sites). For the DMMP study, the project area or Area of Potential Effect (APE) consists of

the four Lower Snake River (Ice Harbor, Lower Monumental, Little Goose, and Lower Granite) and McNary Dams/reservoirs and

associated project lands along with those areas affected by proposed dredging and disposal activities. Most of the cultural

resources within the APE are prehistoric archaeological sites. Archaeological sites are typically open campsites, housepit villages,

rockshelters, rock art (petroglyphs/pictographs), lithic (stone) quarries and workshops, burial grounds and cemeteries, and isolated

rock cairns, pits, and alignments. Historic sites are also located in the APE and represent Euro-American activities. These include

the remains of farms, towns, trading posts, mining sites, military forts, burial sites, abandoned settlements, and transportation and

industrial facilities.

The third cultural resources category is TCP. A TCP is the beliefs, practices, lifeways, arts, crafts, and social institutions of any

community that has been passed down through the generations, usually orally or through practice. It can be embodied in buildings,

structures, sites, landscapes, and individual objects or groups of buildings, structures, or sites. A TCP often pertains to cultural

sites, natural features, and resources important in traditional social and religious practices that tend to preserve cultural identity. It

encompasses such things as distinctive shapes in the natural landscape, named features in local geography, natural habitats for

important subsistence or medicinal plants, traditional usual and accustomed fisheries, sacred religious sites, and places of spiritual

renewal.

While the preceding discussion provides one description of cultural resources, there are other views of what constitutes cultural

resources. The academic and legal definitions tend to focus on tangible evidence such as sites and artifacts and for this study, the

definition of cultural resources contained in Federal law and regulation will be followed. However, for Native American people, these

definitions are too narrow. They view their entire heritage, including beliefs, traditions, customs, and spiritual relationship to the

earth and natural resources, as sacred cultural resources. This broader definition/view of cultural resources by Native Americans is

acknowledged and a sincere effort will be made to listen to and understand the Tribal position in this regard.

3.5.2 Cultural Resource Significance

Federal agencies’ cultural resources responsibilities are defined in a series of laws and regulations that have been promulgated over

the years. The most comprehensive and far reaching of these is the National Historic Preservation Act of 1966 (NHPA), as amended

(16 U.S.C. 470). The NHPA, together with its implementing regulations (36 Code of Federal Regulations, Part 800), lays out a

process for agencies to follow for historic properties on any proposed Federal undertaking. This process calls for an agency to

identify the APE, identify if historic properties are present and, if so, assess their significance and identify and coordinate with

interested parties. The significance or non-significance of an historic property is based on a set of defined criteria. If determined

significant, an historic property is then eligible for listing in the National Register of Historic Places (NRHP). It is only significant

historic properties that a Federal agency is required to address under the NHPA. Except under rare circumstances, an historic

property must be at least 50 years old to be eligible for nomination to the NRHP. Under Section 106 of the NHPA, it states that a

Federal agency shall take into account the effect of its undertakings on historic properties included in or eligible for inclusion in the

NRHP. It also says that the agency shall afford the Advisory Council on Historic Preservation a reasonable opportunity to comment

on its undertaking. As part of its required Section 106 consultation/coordination process, the Corps also routinely works with

appropriate State Historic Preservation Offices (SHPO), Native American Indian tribes, and other interested parties in managing

historic properties found in the APE. (NOTE: The NHPA refers to cultural resources as historic properties. For purposes of this

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document and for other than this section (i.e., 3.5.2), the term cultural resources will be used.)

3.5.3 Culture History

Culture history describes the known sequence of cultural transformations from the end of the last ice age to the present. Because

the DMMP APE covers several distinct cultural sequence areas, a broader culture history description is presented here that

describes general trends across the Columbia River Basin that are applicable to the APE.

3.5.3.1 Prehistory

Paleoindian people lived more than 10,000 years before present (B.P.), during the rapidly warming terminal Pleistocene period.

Where conditions were favorable, they exploited large mammals such as mammoth, mastodon, camel, and horse, which became

extinct during or shortly after this period. Paleoindians also hunted Pleistocene forms of species such as bison, mountain sheep,

and deer, which were larger than their modern descendants (Butler, 1986). Thrusting spears with large, fluted projectile points were

the main weapon technology.

Early Period (6,000 to 10,000 years B.P.) sites can be identified by the presence of characteristic stone projectile point styles called

Windust and Cascade (Leonhardy and Rice, 1970). Early Period social units (bands) may have inhabited very large territories at low

density, traveling within them to exploit seasonally or locally abundant resources, the most important being large ungulates (Ames,

1988). Prehistoric people also exploited very favorable fishing sites but only seasonally during this period. Peak salmon runs made

salmon harvest at these sites very efficient at certain limited times. Population density was relatively low during this period, and

people relied on residential mobility rather than intensive food production and storage to overcome seasonal food scarcity.

The Middle Period (2,000 to 6,000 B.P.) was accompanied by a continental warming and drying trend that peaked sometime

between 8,000 and 4,000 years ago (Aikens, 1993) and influenced the distribution of vegetation zones. The modern climatic pattern

was established by approximately 4,000 years ago. At or near the beginning of this period, the atlatl, or spear thrower and dart,

replaced the thrusting spear as the dominant weapon technology.

The Late Period begins about 2,000 years ago with the introduction of the bow and arrow, as indicated by small, stemmed projectile

points (Aikens, 1993). Population densities continued to grow throughout the Late Period, fostering an intensification of food

production that included the historically observed pattern of food storage, particularly of dried salmon, roots, and berries for winter

consumption.

The seasonal economic cycle of the native inhabitants of the study area is well known. They lived in winter villages near major rivers

or on the lower reaches of major tributaries, subsisting on food stores during the winter, supplemented by hunting and fishing. They

inhabited large, multifamily lodges covered with tule mats.

In the early spring, people harvested Indian celeries (lomatiums and other species) and fished spawning runs of suckers in the

major rivers. Later, they roamed upland further from the winter villages to collect bitterroot and lomatiums for long-term storage. In

May, they took up posts on the main rivers at favorable fishing sites for the spring chinook runs. The runs peaked for a few days,

then floods in late May made fishing much more difficult in the larger rivers. The people then headed for the mountains to escape

the summer heat, to harvest and dry large quantities of huckleberries, and to hunt deer and other game.

As low summer flows in the rivers made fishing easier, the people returned to harvest the salmon runs that occurred between July

and October. The most important of these was the fall chinook run in September, which produced large quantities of stores for

winter food. Up to one-third of the people’s annual diet may have consisted of salmon. Food plants may have supplied an additional

50 percent of their annual food supply, with game and huckleberries supplying much of the remaining amount (Hunn, 1990).

3.5.3.2 Historic Period

European and American cultural influence began in the early 1700's when European trade items were transported into the

Mid-Columbia and Snake River Basins. The first contact between Euro-Americans and Native Americans in the region occurred in

1805 with the arrival of the Lewis and Clark Corps of Discovery. The Lewis and Clark Corps of Discovery followed the course of the

lower Snake River, traveling through the homelands of the Nez Perce, Palus, Cayuse, and Walla Walla tribes/bands (Coues, 1893).

The Lewis and Clark expedition was followed by other expeditions that further explored the region and established trading

operations.

Missionaries arrived in the 1830's, soon to be followed in the 1840's by increasing numbers of settlers coming west.

In 1855, treaties establishing area reservations were signed between the United States and many of the Plateau Culture Area

tribes/bands. Gold was discovered in Idaho in the 1860's, leading to a rush of settlers into the area. Further settlement was based

on extensive dryland wheat farming. This was the era of the steamboat. Between 1855 and 1880, conflicts arose between

non-Native American settlers and local tribes, resulting in several wars. Tribes and bands were required to relinquish part of their

homelands. Through treaty negotiations, many tribes and bands legally retained certain pre-existing rights that allow them to fish at

usual and accustomed areas and to hunt, gather, and graze livestock on open and unclaimed lands.

The 1880's brought construction of railroads and continued settlement. The 1900's have seen the damming of the rivers, expansion

of urban developed areas and agricultural lands, increased recreation, navigation of the rivers, the development of major irrigation

projects, and continued growth in the region.

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3.5.4 Existing Cultural Resources Environment

There are approximately 600 known archaeological sites within the APE, many of which are partially or completely inundated. The

known sites are both prehistoric and historic and range in age from the earliest period of human occupation to recent times.

Identified prehistoric sites include villages, fishing sites, burials, rock art (petroglyphs and pictographs), storage pits, and temporary

camps. Historic sites include homesteads, mining sites, forts, towns, farmsteads, and trading posts.

Four archaeological districts (Tri-Cities, Lower Snake River, Windust Caves, and Palouse Canyon) and four sites (45FR5, 45FR50,

45FR272, and 10NP151) are listed in the NRHP. 45FR50 is also a designated National Historic Landmark. In addition to these

NRHP sites and districts, two other sites have been determined NRHP eligible – 45FR283 and 45WT78/79. (NOTE: Cultural

resources determined NRHP eligible are afforded the same level of consideration and protection as sites listed on the NRHP.) Many

other cultural resources within the APE are potentially eligible for NRHP nomination, but have not been thoroughly evaluated or

nominated.

In summary, the NRHP and NRHP eligible sites and districts in the APE include:

McNary Dam, Lake Wallula

Tri-Cities Archaeological District (listed)

Lower Snake River Archaeological District (listed)

45FR5 (listed)

45FR283 (determined eligible)

Ice Harbor Dam, Lake Sacajawea

Windust Cave Archaeological District (listed)

45FR272 (listed)

Lower Monumental Dam, Lake West

Palouse Canyon Archaeological District (listed)

45FR50 (listed, National Historic Landmark)

Little Goose Dam, Lake Bryan

No sites currently listed or determined eligible

Lower Granite Dam, Lower Granite Lake

10 NP 151 (listed)

45WT78/79 (determined eligible)

Most scientific information generated about cultural resources found in the APE is the result of archaeological studies associated

with the construction of Federal dams in the study area. Comprehensive archaeological surveys have been done for all the

reservoirs. Evaluation of recommended sites in McNary, Ice Harbor, and Little Goose reservoirs were completed by the end of 2001.

Evaluation of recommended sites in Lower Monumental and Lower Granite reservoirs will be completed by the end of 2002.

3.6 SOCIOECONOMICS

The socioeconomic effects of implementing a long-term plan for maintaining the navigation channel in the lower Snake River and

McNary reservoirs would be seen primarily within the communities along the river system that are, in some way, involved with

commercial river navigation. Broader economic effects stem from the movement of commodities outside the study area. Levee raises

and road modifications in the Lewiston/Asotin area would be expected to produce localized socioeconomic effects through the

construction activities it would entail.

The socioeconomic factors of population, employment, income, and environmental justice communities for the study area are

presented in the sections below.

3.6.1 Population

The populations of the counties in the planning study area are shown in table 3-3.

Table 3-3

Study Area Population By County

County State

Estimated

1998

Population

1990

Population

1980

Population

Asotin WA 21,264 17,605 16,823

Benton WA 136,250 112,560 109,444

Columbia WA 4,156 4,024 4,057

Franklin WA 46,459 37,473 35,025

Garfield WA 2,330 2,248 2,468

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Nez Perce ID 36,852 33,754 33,220

Umatilla OR 65,495 59,249 58,861

Walla Walla WA 53,702 48,439 47,435

Whitman WA 39,487 38,775 40,103

Source: U.S. Department of commerce, Bureau of the Census

The estimated 1998 population of all the counties in the study is 405,995. This represents a 14.6 percent increase from the 1990

population, with only Garfield County, Washington, experiencing a small decrease in population. The study area is generally rural in

nature with the Tri-Cities area, near the confluence of the Snake and Columbia Rivers, and the Lewiston-Clarkston area, near the

confluence of the Clearwater and Snake Rivers, being the main population centers in the study area.

Study area counties have shown generally higher annual growth rates in the 1990's than in the 1980's or, in the case of some

counties, lowered rates of population decline. In the 1980's, the region’s growth rate lagged behind the overall growth rates of the

states of Washington, Idaho, and Oregon (17.77 percent, 6.65 percent, and 7.95 percent, respectively), due in large part to the

rapid growth of the more heavily populated urban areas in these states during the same time periods.

3.6.2 Employment and Income

Regional employment, as projected by the U.S. Department of Commerce, Bureau of Economic Analysis, Regional Economic

Information System, is summarized in table 3-4.

Table 3-4

Study Area 1997 Employment By County

County State

Jobs By Sector

Non-Farm Farm

Asotin WA 7,028 232

Benton WA 71,414 4,657

Columbia WA 1,935 306

Franklin WA 21,492 4,213

Garfield WA 1,021 293

Nez Perce ID 25,741 464

Umatilla OR 31,751 3,156

Walla Walla WA 27,543 2,590

Whitman WA 19,367 1,590

Source: U.S. Department of Commerce Bureau of Economic Analysis

Within the study area, total county non-agricultural employment was highest in Benton County, Washington, which is the most

populous and highly urbanized county in the study area. Correspondingly, non-agricultural employment totals were lowest in rural

counties with low populations (Columbia and Garfield counties in Washington).

Table 3-5 presents income data for the study area counties. Per capita incomes in the study area counties are generally consis tent

with or higher than statewide per capita incomes for their respective states. Estimated income-based 1995 poverty rates within the

study area counties range from a low of 8.7 percent in Benton County, Washington, to a high of 17.0 percent in Umatilla County,

Oregon.

Table 3-5

Study Area Income By County

County State

1993

Per Capita

Income

Asotin WA 17,503

Benton WA 21,037

Columbia WA 23,017

Franklin WA 17,234

Garfield WA 22,495

Nez Perce ID 18,834

Umatilla OR 16,368

Walla Walla WA 17,180

Whitman WA 16,021

Source: U.S. Department of Commerce, Bureau of Economic Analysis

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3.6.3 Environmental Justice Communities

As outlined in Executive Order 12898, federal agencies must evaluate environmental justice (EJ) issues related to any project

proposed for implementation. This evaluation includes identification of minority and low-income populations in the project area,

identification of any negative project impacts that would disproportionately affect these low-income or minority groups, and proposed

mitigation to offset the projected negative impacts.

3.6.3.1 Geographic Identification of EJ Communities

The Project Area for the DMMP environmental justice analysis was defined as all the census tracts adjacent to the lower Snake

River and McNary reservoir where the proposed project activities would occur. The most recent complete demographic data sets

available were reviewed for this analysis. Data from the U.S. Bureau of Census 2000 decennial census on the racial demographics

of each tract and Census 1990 data on the percent of inhabitants living in poverty for each tract were analyzed to determine the

locations of communities sensitive to environmental justice issues. Poverty data from the 1990 Census were determined to be

appropriate for this analysis due to the fact that county-wide poverty levels either dropped or stayed the same in the project area

between 1990 and 1997 (American Factfinder 2002). Given the large area potentially affected by the DMMP alternatives, Census

tract- level data were determined to be the appropriate level of data for review. Census tracts are geographic subdivisions of

Counties, generally with between 1,000 and 8,000 people, with an optimum size of 4,000 people.

The percent minority inhabitants and percent of inhabitants living in poverty in each tract were compared to the state average for

each tract’s respective state. Tracts with above average percent minority or percent poverty were identified as locations with potential

environmental justice populations.

As seen in figure 3-2, most of the land adjacent to the project area is below average in terms of the number of residents living in

poverty. The exceptions are tract 9601 in Columbia County, WA, tracts 0201, 0204, and 0206 in Franklin County, WA, tracts 9803

and 9806 in Asotin County, WA, tracts 011001, 0113, 011501, and 0116 in Benton County, WA, tract 9508 in Umatilla County, OR,

and tract 990398 in Nez Perce County, ID. The number of inhabitants living in poverty in each Census tract as of 1990 is shown in

table 3-6.

Source: U.S. Census 1990 GIS Data, http://esri.com/data/online/tiger

Figure 3-2. Project Area 1990 Census Tract Data: Percent Inhabitants Living in Poverty

Table 3-6

Percent Poverty of Project Area Census Tracts 1990

Census

Tract

County

and State

Percent

Poverty

State

Average

Percent

Poverty

Above

Average?

9802 Asotin, WA 10.5% 10.9% no

9803 Asotin, WA 31.2% 10.9% yes

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9806 Asotin, WA 17.7% 10.9% yes

0101 Benton, WA 2.4% 10.9% no

0105 Benton, WA 9.7% 10.9% no

0106 Benton, WA 10.3% 10.9% no

010802 Benton, WA 2.4% 10.9% no

010901 Benton, WA 10.3% 10.9% no

011001 Benton, WA 11.4% 10.9% yes

0113 Benton, WA 22.1% 10.9% yes

011501 Benton, WA 14.3% 10.9% yes

0116 Benton, WA 15.6% 10.9% yes

0120 Benton, WA 0.0% 10.9% no

9601 Columbia, WA 11.8% 10.9% yes

0201 Franklin, WA 43.0% 10.9% yes

0204 Franklin, WA 30.1% 10.9% yes

020501 Franklin, WA 6.3% 10.9% no

020502 Franklin, WA 5.4% 10.9% no

0206 Franklin, WA 13.0% 10.9% yes

0207 Franklin, WA 10.0% 10.9% no

9701 Garfield, WA 9.9% 10.9% no

9702 Garfield, WA 10.3% 10.9% no

9903 Nez Perce, ID 23.7% 13.3% yes

9904 Nez Perce, ID 12.5% 13.3% no

9905 Nez Perce, ID 2.9% 13.3% no

9907 Nez Perce, ID 11.4% 13.3% no

9504 Umatilla, OR 8.8% 12.4% no

9508 Umatilla, OR 18.6% 12.4% yes

9200 Walla Walla, WA 6.8% 10.9% no

0010 Whitman, WA 10.7% 10.9% no

Source: U.S. Census 1990 GIS Data, http://esri.com/data/online/tiger

As shown in figure 3-3, the central and eastern regions of the project area are below average in terms of minority inhabitants. The

tracts at the west end of the project area, however, are home to significant minority populations. Specifically, tracts 020100, 020400,

020502, 020601, 020602, and 020700 in Franklin County, WA, tracts 010901, 011600, and 012000 in Benton County, WA, tract

920000 in Walla Walla County, WA, and tract 950800 in Umatilla County, OR have populations composed of an above average

percentage of minorities.

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Source: U.S. Census 200 GIS Data, http://geographynetwork.com/data/tiger2000

Figure 3-3. Project Area 2000 Census Tract Data: Percent Minority Inhabitants

The percentage of minority inhabitants living in each project area census tract as of the year 2000 is shown in table 3-7.

Table 3-7

Percent Poverty of Project Area Census Tracts 2000

Census

Tract

County

and State

Percent

Poverty

State

Average

Percent

Poverty

Above

Average?

980200 Asotin, WA 1.7% 21.1% No

980300 Asotin, WA 4.6% 21.1% No

980600 Asotin, WA 3.6% 21.1% No

012000 Benton, WA 36.1% 21.1% Yes

010100 Benton, WA 8.4% 21.1% No

010600 Benton, WA 10.3% 21.1% No

010804 Benton, WA 11.8% 21.1% No

010901 Benton, WA 22.1% 21.1% Yes

011001 Benton, WA 17.8% 21.1% No

011501 Benton, WA 17.8% 21.1% No

011600 Benton, WA 61.0% 21.1% Yes

960200 Columbia, WA 8.8% 21.1% No

020700 Franklin, WA 25.1% 21.1% Yes

020601 Franklin, WA 46.2% 21.1% Yes

020602 Franklin, WA 28.1% 21.1% Yes

020501 Franklin, WA 11.0% 21.1% No

020502 Franklin, WA 29.3% 21.1% Yes

020400 Franklin WA 100.0% 21.1% Yes

020100 Franklin, WA 100.0% 21.1% Yes

970100 Garfield, WA 3.6% 21.1% No

970200 Garfield, WA 3.3% 21.1% No

990300 Nez Perce, ID 6.9% 12.0% No

990400 Nez Perce, ID 4.2% 12.0% No

990500 Nez Perce, ID 3.8% 12.0% No

990700 Nez Perce, ID 2.7% 12.0% No

950400 Umatilla, OR 12.7% 15.4% No

950800 Umatilla, OR 43.6% 15.4% Yes

920000 Walla Walla, WA 40.2% 21.1% Yes

001000 Whitman, WA 2.7% 21.1% No

Source: U.S. Census 2000 GIS Data, http://geographynetwork.com/data/tiger2000

3.6.3.2 Economic and Cultural Identification of EJ Communities

The nature of the project requires discussion of other environmental justice communities that may be affected by the proposed

project but which are not apparent from the geographic identification performed above. As described in the Lower Snake River

Juvenile Salmon Migration Feasibility Study EIS (FR/EIS), these groups include Native American tribes that depend on the cultural

and aquatic resources in the Snake River, and Hispanic farm workers whose jobs depend on the irrigation and freight transport

systems supported by the Snake River.

The Corps’ public involvement process is an important factor in assessing project impacts relative to environmental justice concerns.

Section 6 of the DMMP/EIS describes the public involvement process, including specific consultations with Tribes in the region. Input

received through the public involvement and tribal consultation processes have been considered in the analysis of environmental

justice.

3.7 TRANSPORTATION

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The proposed navigation maintenance dredging on the Columbia and Snake Rivers and restoration of flow conveyance in the Lower

Granite reservoir would maintain the integrity of the integrated barge, rail, and highway transportation system serving the study

area. The proposal could result in limited short-term affects to barge, rail, and highway service in the area during the construction of

various project features; however, the overall long-term impacts would be beneficial to transportation services in the area. This

section describes the transportation network and provides the basis for assessing the impacts.

3.7.1 River Navigation

Navigation on the Columbia and Snake Rivers has historically provided an important route of access into and from the interior

Columbia and Snake River basins. Commercial traffic operates on the Columbia River from its mouth through the Tri-Cities area in

Washington. On the Snake River, commercial traffic uses the waterway from its confluence with the Columbia River at Pasco,

Washington, to Lewiston, Idaho. The Federal government, through the Corps, operates and maintains the congressionally

authorized navigation channels and locks throughout the navigable waterway of the Columbia and Snake Rivers.

The navigation channel, from the confluence of the Snake River with the Columbia River to Lewiston, is authorized to a depth of 14

feet (4.3 m) and a width of 250 feet (76.2 m). There are navigational locks at four dams on the lower Snake River: Ice Harbor, Lower

Monumental, Little Goose, and Lower Granite. The confluenc e of the Snake and Columbia Rivers is in the McNary reservoir. A

comprehensive inventory of port facilities on the Columbia and Snake Rivers above McNary is presented table 3-8.

Table 3-8

Inventory of Commercial Facilities on the Columbia and Snake River Reservoirs Above McNary Dam

Facility Name Mile Owner Use

Lower Granite Reservoir

Tidewater Terminal Co. 135.5 Tidewater Terminal Co. Containers, R petrol prods,

liquid fertilizer, and salt

Port of Whitman County, Site H Wharf 135.6 Port of Whitman County Logs and general cargo

Potlatch Corp Dock 135.7 Potlatch Corp Ship wood chips

Mountain Fir Lumber Co., Wilma Dock 136.0 Longview Fibre Co. Ship wood chips

Stegner Grain Terminal Dock 136.5 Port of Whitman County Grain shipment

Port of Whitman County Docks 137.0 Port of Whitman County Logs, general cargo

Port of Clarkston Dock 137.8 Port of Clarkston Containers, logs, heavy lift

Clarkston Grain Terminal Dock 138.4 United Grain Corp Grain shipment

Mountain Fir Lumber Co

Lewiston Div Dock (Clearwater River) 0.5 Longview Fibre Co. Ship wood chips and boggedfuel

Port of Lewiston Container Terminal 1.1 Port of Lewiston Containers, cargo, lumber,

paper

Continental Grain Co., Lewiston Dock 1.3 Continental Grain Co. Grain shipment

Lewis-Clark Terminal Association Dock 1.4 Lewis-Clark Term. Assoc.,

Inc. Grain shipment

Little Goose Reservoir

Pomeroy Grain Growers Dock 83.0 Port of Garfield Grain shipment

Columbia Grain 83.5 Port of Whitman County Grain shipment

Central Ferry Elevator

Central Ferry Terminal 83.7 Central Ferry Terminal

Assoc. Grain shipment

McGregor Terminal NA McGregor Company Ammonia shipment

Almota Elevator Co. Dock 103.6 Almota Elevator Co. Grain shipment

Port of Almota Dock, S&R Grain 103.7 Port of Whitman Grain, receive liquid fertilizer

McNary Reservoir

Port of Umatilla Cargo Dock 292.5 Port of Umatilla Containers, wood chips,

heavy lift

Pendleton Grain Growers 292.7 Pendleton Grain Growers Grain shipment

Tidewater Barge Lines 292.8 Tidewater Barge Lines Petrol prods, liquid fertilizer,

fueling vehicles

Walla Walla Grain Growers 311.6 Walla Walla Grain

Growers Grain shipment

Walla Walla Grain Growers 311.6 Walla Walla Grain

Growers Grain shipment

Port of Walla Walla at Boise Cascade

Wallula Plant 314.5 Port of Walla Walla Wood pulp shipment

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Phillips Pacific Chemical Co. 321.6 Phillips Pacific Chemical

Co. Shipment of liquid fertilizer

Chevron Chemical Co. 322.6 Chevron Chemical Co. Not used

Unocal Chemicals 323.6 Unocal Chemicals

Division Ammonia and urea

Northern Pacific Grain Growers 328.0 Northern Pacific Grain

Growers Grain shipment

Port of Benton/Barge Slip 343.1 Port of Benton Cargo, heavy lift

Port of Benton 342.7 Port of Benton General cargo

Port of Pasco Marine Terminal 328.2 Port of Pasco Grain, receive petroleum

products

Pasco Container Terminal/Barge Slip 326.8 Port of Pasco Container, heavy lift, barges

Port of Walla Walla Dock 1.7 Port of Walla Walla Not used

Connell Grain Growers 1.8 Port of Walla Walla Grain shipment

Cargill Burbank Grain Elevator Dock 2.0 Port of Walla Walla Grain shipment

Chevron Pipe Line Co., East Pasco

Terminal 2.2 Chevron USA, Inc. Petroleum products

Tidewater Terminal Co. Mooring Docks 2.7 Tidewater Terminal Co. Mooring vessels, handling

supplies

Tidewater Terminal Co. 2.9 Tidewater Terminal Co. Petroleum products

Tidewater Terminal Co. Molasses Dock 3.0 Tidewater Terminal Co. Molasses, liquid fertilizer

Ice Harbor Reservoir

Walla Walla Grain Growers, Sheffler Dock 29.0 Walla Walla Grain

Growers Grain shipment

Louis Dreyfus Windust Station Dock 38.5 Louis Dreyfus Corp. Grain Shipment

Lower Monumental Reservoir

Columbia County Grain Growers

Lyons Ferry Dock 61.1 Columbia County GrainGrowers, Inc. Grain shipment

Source: Columbia River System Operation Review FEIS, November 1995

Port facilities at Clarkston and Lewiston have histories of siltation, which occurs because of the changes in river flow as the Snake

River and Clearwater River enter the reservoir formed behind Lower Granite. River current velocity decreases as it enters the

reservoir, dropping large amounts of sediment. Maintaining water depths has been most critical on the south side of the river at

Clarkston and, to a lesser extent, at Lewiston. Facilities on the north bank downstream of the Clearwater-Snake Rivers confluence

have reported few problems.

On the McNary reservoir, eddies and other conditions cause marginal water depths at some facilities, especially downstream of

Clover Island. These depths have continued to cause docking problems for grain and short-term storage elevators in the Tri-Cities

area. Other facilities with marginal water conditions present are located at Burbank and Wallula. The Columbia and Snake Rivers

waterway serves an enormous area that covers much of the western United States. Agriculture dominates the regional industries

associated with waterborne commerce. Trade revolves around grains (primarily wheat, alfalfa, corn, grass seed, fruits, and

vegetables) with wheat being the largest export item. Other regional industries that use water transportation include aluminum, pulp

and paper, petroleum, logs, lumber, and beef. Products shipped on the shallow draft channel are comprised mainly of wheat, grain,

wood products, logs, petroleum, chemicals, and other agricultural products. Containerized commodities are also transported via the

waterway. Containers are typically loaded at Lewiston and Pasco with approximately 97 percent of these shipments destined for

Portland and the remainder going to Vancouver, Washington. Petroleum and fertilizer products have historically made up the bulk

of upriver barge shipments on the waterway (Corps, 1995). The forecast of barge shipments over the Columbia and Snake Rivers

waterway above McNary is presented in table 3-9. Typically, a "barge shipment" is comprised of one four-barge raft and a tow,

which can transport 14,000 tons (12 709.2 metric tons) of grain or other bulk commodities.

Table 3-9

Projected Commodity Growth for Shipments Above McNary Lock and Dam

Commodity 1996 2000 2004 2010 2014 2020 2024 2030 2040 2050 2060 2070 2074

Wheat and Barley 4,363 4,641 5,038 5,036 5,035 5,289 5,458 6,092 6,092 6,092 6,092 6,092 6,092

Other Food and Farm 91 104 104 104 104 104 104 104 104 104 104 104 104

Petroleum 1,709 1,569 1,569 1,569 1,569 1,569 1,569 1,569 1,569 1,569 1,569 1,569 1,569

All Others 7 2 2 2 2 2 2 2 2 2 2 2 2

Empty Containers 16 16 16 16 16 16 16 16 16 16 16 16 16

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Metals 6 4 4 4 4 4 4 4 4 4 4 4 4

Chemicals 199 241 262 262 262 275 274 317 317 317 317 317 317

Wood Products 28 69 69 69 69 69 69 69 69 69 69 69 69

Wood Chips and Logs 528 581 581 581 581 581 581 581 581 581 581 581 581

Total 6,947 7,228 7,646 7,644 7,643 7,910 8,088 8,755 8,755 8,755 8,755 8,755 8,755

Source: Corps, 1995

3.7.2 Railroads

Washington, Oregon, Idaho, and Montana are served by the Burlington Northern and Santa Fe Railroad (BNSF), the Union Pacific

Railroad (UPRR), and several short- line operations. Among the latter, the Camas Prairie Railroad serves Idaho and Washington,

the Blue Mountain Railroad serves Washington, and the Montana Rail Link serves Idaho and Montana.

In Washington, the BNSF and UPRR have an agreement to jointly manage the main line track from Seattle to Portland. From

Vancouver, Washington, the BNSF line runs along the northern side of the Columbia River through the Tri-Cities to Spokane. It

continues north to Sandpoint, Idaho, then runs southeast to Missoula, Montana, and on into the Midwest. The BNSF has crossings

into Oregon at Portland, Wishram, and Wallula. The UPRR runs along the southern side of the Columbia River from Portland to

Hinkle, Oregon, then runs south to Boise and on into the Midwest. Both the BNSF and the UPRR provide extensive trackage in all

four states.

The Camas Prairie Railroad is a joint venture operated cooperatively by the BNSF and UPRR. Camas Prairie tracks connect Revling

and Kamiah in Idaho through Lewiston to Riparia on Lower Monumental reservoir in Washington. The Camas Prairie tracks cross the

Clearwater River near the west Lewiston levee and run down the lower Snake River canyon along the north shore of Lower Granite,

Little Goose, and Lower Monumental reservoirs. Montana Rail Link provides service from Sandpoint, Idaho, to Garrison, Montana.

(Corps, 1992)

3.7.3 Highway/Roadway

The highway network serving the study area includes interstate, Federal, state, and county highways. Table 3-10 lists the key

highways and roadways in the study area.

Table 3-10

Key Highways and Roadways

Highway/Roadway Segment/Location

Primary Highways

Interstate 84 U.S. 97 (Biggs) to Pendleton

Interstate 82 I-84 to U.S. 395 (Pasco)

U.S. 395/730 I-84 to U.S. 12

U.S. 12 U.S. 395 (Pasco, WA) to Lewis Co., ID

U.S. 95 Lewis and Adams County, ID

OR 11 I-84 to WA State Line

WA 14 U.S. 97 (Maryhill) to I-82 (Plymouth)

WA 124 U.S. 12 (near Pasco) to U.S. 12 (Waitsburg)

WA 125 WA 125 to OR State Line

WA 193 U.S. 12 to Port of Wilma

Secondary Highways

U.S. 395 U.S. 12 (Pasco) to WA 260 (near Mesa)

WA 260 U.S. 395 to WA 261

WA 261 WA 260 to U.S. 12

WA 127 U.S. 12 to Central Ferry

WA 129 U.S. 12 to OR State Line

Alternate Routes North From The Snake River

U.S. 195 U.S. 12 to WA 26

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WA 26 U.S. 195 to U.S. 395

WA 260 WA 261 to WA 26

Source: Columbia River Flow Measures Options Analysis/EIS, January 1992.

Roads that have the greatest potential to be impacted by the proposed levee raise alternatives in the Lewiston, Idaho, and Asotin

and Clarkston, Washington, areas are:

U.S. Highway 12 as it parallels the Snake River below the mouth of the Clearwater River.

Whitman County Road 900 north of the Snake River below the mouth of the Clearwater River.

Washington Highway 129 between Clarkston and Asotin.

Snake River Road upstream of Asotin.

Snake River Avenue on the east bank of the Snake River upstream from the mouth of the Clearwater River.

The higher proposed levee raise alternative would impact the greatest number of roads within the Lewiston/Clarkston area and

require more significant modifications. Conversely, the lower proposed levee raise alternative would have a limited impact to a small

number of roads in the area. See appendix E for details.

3.8 GEOLOGY AND SOILS

Existing Environment

The Clearwater and Snake Rivers drain portions of southeastern Washington and southwestern Idaho. The Snake River, in turn,

drains to the Columbia River. The Columbia’s watershed includes eastern and central Washington, north-central Oregon, and

portions of Idaho and the Canadian provinces of British Columbia and Alberta. The physiographic provinces within the area of

consideration include the Columbia Basalt Plain, the Rocky Mountains, and the Blue Mountains (Baker et al., 1987; Galster et al.,

1989). The Clearwater River originates in Idaho and flows west through the Columbia Basalt Plain where it is joined by the Snake

River. The lower Snake River flows north along the eastern margin of the Blue Mountains, then turns west as it flows through the

Columbia Basalt Plain. Along much of the Columbia Basalt Plain and the Blue Mountains, these two rivers flow within canyons that

are several hundred to over 2,000 feet (610 m) deep.

The bedrock geology of the Columbia Basalt Plain consists primarily of thick successions of basaltic lavas. Numerous basaltic

formations are distinguished within these lavas, and they are generally known as the Columbia River Basalt Group (CRBG) (Galster

and Sager, 1989). The original extrusion of these basalts blocked rivers and impounded lakes. Therefore, several areas have fluvial

and lacustrine sedimentary rock intercalcated between the basalt flows. The Blue Mountains have a core of volcanic and

sedimentary rocks. To the north, these core rocks are covered by the CRBG, which, in turn, has been upwarped slightly by the Blue

Mountains. To the east, the Snake River flows along the flank of the Blue Mountains where the CRBG does not obscure the

underlying rocks.

During the Quaternary period (2 million years ago to present), repeated advances of the Lake Pend Oreille lobe of the Cordilleran

ice sheet dammed the Clark Fork River and impounded glacial Lake Missoula. This lake released catastrophic floods numerous

times during the late Pleistocene Epoch (1.7 to 2 million years ago), scouring much of the surface of the Columbia Basalt Plain. In

the vicinity of Grand Coulee Dam, another glacier lobe dammed the Columbia River creating glacial Lake Columbia (Hansen, 1989).

The glacial Lake Missoula floods entered and overtopped this lake. A similar flood emerged from pluvial Lake Bonneville (now Great

Salt Lake) and flowed down the Snake River (Malde, 1968).

These floods eroded the river valleys and produced large deposits of river sediments (Baker et al., 1987). These river deposits occur

as scattered terraces along the river valleys. The flood erosion also produced steep slopes that have undergone some retreat,

producing steep, coarse-grain talus slopes along the bedrock cliffs. Post-glacial river incision has reworked some of the older river

deposits producing lower elevation and younger alluvial terraces that are scattered along the rivers. Since impoundment, some

smaller rivers have deposited alluvial fans where they enter the reservoirs; others are completely drowned, forming small

embayments. All the Pleistocene and contemporary river and alluvial fan deposits consist of gravels and sands with minor amounts

of silt and clay. The proposed upland disposal site at Joso has historically been used for sand and gravel mining.

During the Pleistocene and into the post-glacial period, winds eroded exposed fine-grain sediments. These silt-size sediments,

known as loess, have been deposited over large areas. These deposits are most common on the upland surfaces of the Columbia

Basalt Plain in a region known as the Palouse (Busacca et al., 1985). These materials occur only to a minor extent around the

perimeter of the region's reservoirs. At Ice Harbor, there is a large wind-derived sand deposit (Miklancic, 1989a), and small areas of

sand dunes exist along some reservoirs.

Sedimentation within the reservoirs is dominated by river influx and wave-eroded materials. The heavier sediments (gravels and

sands) can no longer be transported beyond the length of each reservoir. Lighter sediments (silts and clays) move through

spillways, fishways, and powerhouses. River erosion is concentrated within a narrow band between high- and low-reservoir levels

along the upper reservoir shorelines. Based on historic dredging within the study area, it is estimated that the river sediments that

may be dredged are approximately 85 percent sand, gravel, and cobbles, and approximately 15 percent silts.

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The Joso site, a potential upland disposal site, includes soils from the following soil groups: Basalt Rock, Magallon, and Quincy

Fine Sand. The Joso site includes a thin strip of Basalt Rock formations located along the shoreline of the Snake River. Along this

area, basalt rock cover is exposed 25 to 90 percent and slopes range from 30 to 60 percent. The soil between exposures ranges in

thickness from a few inches to 1 foot (a few centimeters to 30.5 cm). The area contains numerous loose, angular, basalt stones and

cobbles. The inner portion of the Joso site contains large areas of Magallon soils. These areas are described as very rocky, very fine

sandy loam with 0 to 30 percent slope. The areas are well drained and somewhat excessively drained soils that have developed

from alluvium over glacial outwash. The areas have low shrink-swell potential. Both soil groups have a low to medium potential for

erosion, but erosion is minimal as long as there is vegetative cover.

3.9 WATER QUALITY/WATER RESOURCES

This section describes the existing water quality, wetland, and floodplain conditions of the affected environment. Significant humancaused changes have occurred to some water quality, wetland, and floodplain parameters over the past century in the Clearwater,

Snake, and Columbia River systems. These changes range from a shift in temperature characteristics to introduction of nutrients

and exotic radionuclides (IDHW, 1982; Pruter and Alverson, 1972; Vigg and Watkins, 1991). Other impacts include inundation of

existing wetland and river delta areas and the subsequent redevelopment of these resources at the new reservoir levels.

Because of the distinctive nature of their general water quality, each of these river systems is discussed separately following the

discussion of water quality criteria. The primary emphasis is on the key water quality parameters of turbidity, dissolved oxygen,

temperature, pH, and chemicals of concern. Chemicals of concern are substances such as metals, organometallic and organic

compounds, chlorinated hydrocarbons, phthalates, phenols, and pesticides that, based on their concentrations, may pose a

potential risk to human or ecological health in the aquatic environment. Special emphasis was placed on examination of sediment

nutrient loads and their effects to the water column if re-suspended. Of particular interest is the deleterious effect from elutriated

ammonia to be detailed in subsequent paragraphs of this section. Reviews of existing water quality and sediment data and previous

environmental documentation were used to assess the affected environment and project environmental effects as they relate to

water quality and water resources. For some chemicals of concern, such as metals, limited water quality data were available; these

limitations are acknowledged in this discussion. Written summaries of recent water quality and tabular summaries of recent

sediment quality data are provided in appendix H, Water Quality/Water Resources. Summary tables of the historical water and

sediment quality data for the proposed dredging and disposal sites are included in appendix H. See also the Feasibility Study,

Appendix C as that information is incorporated by reference.

Since there are no uniform freshwater sediment quality criteria that provide a definitive numerical standard for evaluation of dredged

material, the Corps is developing a Mid-Columbia and Lower Snake River Region Sediment Testing Framework. In the interim, the

Dredged Material Evaluation Framework: Lower Columbia River Management Area will be used by the Corps to evaluate the

potential water quality impacts of dredging and dredged material management and the suitability of dredged material for in-water

disposal. The specific procedures in the Lower Columbia Framework will be used and evaluated for their applicability for adoption as

part of the Mid-Columbia and Lower Snake River framework.

3.9.1 Water Quality Criteria and Standards

The EPA and the states of Idaho, Oregon, and Washington have established surface water criteria or standards for the Snake and

Columbia River Basins. Relevant references include the EPA National Quality Criteria for Water or "Gold Book" criteria (EPA, 1986),

Washington Water Quality Criteria, the 1999 Update of Ambient Water Quality Criteria for Ammonia (EPA, 1999), Water Quality

Standards And Wastewater Treatment Requirements: Idaho Administrative Procedures Act (IDAPA) 58.01.02, and Oregon Water

Quality Criteria. Water quality standards for Oregon, Idaho, and Washington are summarized in table 3-11.

Table 3-11

Water Quality Standards in Oregon, Idaho, and Washington

Parameters Oregon Idaho Washington

Temperature

≥ 68 °F (20 °C): No increase, single source Maximum instantaneous temp: 72 °F (22 °C)1 Temp: ≤ 68 °F (20

°C)

≤ 67 °F (19.7 °C): Increase < 0.5 °F (0.28 °C),

single source Daily average: < 66°F (19 °C)

Temp: < 34 (T1 +

< 66 °F (19 °C); Increase < 2 °F (1.1 °C), all 9) °C

sources

Maximum instantaneous temp: 55 °F (13 °C)2

Daily average: < 48 °F (9 °C)

Dissolved

Oxygen ≥ 90-percent saturation

≥ 6.0 mg/L, 30-day mean

≥ 8 mg/L

≥ 4.7 mg/L, 7-day mean

≥ 3.5 mg/L, minimum

≥ 6.0 mg/L or 90-percent saturation

(salmonids spawning)

Total

Dissolved

Gas

≤ 110-percent saturation4,6

≤ 110 percent

≤ 110 percent4

≤ 105 percent saturation5

< 120 percent,

during salmon

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migration6

Turbidity ≤ 10-percent increase

≤ 5 nephelometric turbidity unit (NTU)

increase7

≤ 5 NTU increase7

< 10 NTU increase8

< 10 NTU

increase8

< 50 NTU9

< 10 NTU10

pH 6.5 - 8.5 6.5 - 9.0 6.5 - 8.5

Fecal

coliform 100 organisms/100 mL11 100 organisms/100 mL11 100 organisms/100mL11

1Standards for the Snake River; Clearwater River confluence (RM 139) to Asotin, WA (RM 147)

2Standards for the Clearwater River; mouth (RM 0) to Potlatch River confluence (RM 15). This reach is designated as a "Special Resource Water."

3T = Background Temperature

4Except when streamflow exceeds 10-year, 7-day average flood frequency

5

In hatchery-receiving waters and when depth is < 2 feet (0.6 m)

6Waivers to 120 percent in tailrace and 115 percent in forebay of downstream dam, with 125 percent maximum for 1 to 2 hours during voluntary spills.

7

If background is ≤ 50 NTU.

8

If background instantaneous measure is > 50 NTU.

9

Instantaneous, outside mixing zone.

10Ten consecutive days.

11Geometric Mean.

Source: Developed by Normandeau/Corps

All three states have established a policy of antidegradation and beneficial uses for their surface waters, which precludes the

discharge or introduction of toxic or hazardous materials (e.g., the EPA's 126 priority pollutants) or deleterious contaminants. Since

the codes, rules, and regulations for these state standards are voluminous, only highlights of the standards are presented in this

document--specifically, turbidity, dissolved oxygen, temperature, and pH are discussed below in sections 3.9.1.2 through 3.9.1.6.

Specific water quality conditions in the lower Snake, Clearwater, and Columbia Rivers are presented in sections 3.9.1.8 through

3.9.1.10.

3.9.1.1 Beneficial Use Criteria

In Idaho, beneficial use is defined as domestic water supply (DWS), industrial water supply, and agricultural water supply;

cold-water and warm-water biota; salmonid spawning; primary and secondary contact recreation; wildlife habitats; and aesthetics.

All except warm-water biota have been designated as beneficial uses for this portion of the Clearwater River, and the Snake River

downstream of Brownlee reservoir.

Idaho regulations also contain criteria to establish Special Resource Waters. The criteria for Special Resource Waters are:

a. Water of outstanding high quality, exceeding criteria for primary contact recreation and cold-water biota;

b. The water possesses an outstanding aesthetic and recreation quality;

c. Intensive protection the water is of paramount interest to the people of Idaho;

d. The water is of unique ecological significance;

e. Intensive protection of the water is necessary to maintain an existing, but jeopardized use;

f. And, the water is part of a natural Scenic River, national park, state park, or of major importance to the same.

g. The Feasibility Study’s water quality evaluation is incorporated by reference.

The State of Washington has a four-level water quality classification system that ranges from AA (extraordinary) to C (fair). The State

of Washington has classified the Columbia River from Grand Coulee Dam downstream to the Pacific Ocean, and the Snake River as

Class A (excellent). Beneficial uses are water supply (domestic, industrial, agricultural); stock watering; fish and shellfish rearing,

spawning, and harvesting; wildlife habitat; recreation (primary contact); and commerce and navigation (WAC Chapter 173-201A,

11/18/97).

Oregon defines the study area portions of the Columbia River as beneficial for public and private domestic supply, industrial water

supply, irrigation, livestock watering, anadromous fish passage, salmonid fish rearing, salmonid fish spawning, resident fish and

aquatic life, wildlife and hunting, fishing, boating, water contact recreation, aesthetic quality, hydropower, and commercial

navigation and transport (Oregon State Water Quality Standards as of November 2001).

3.9.1.2 Turbidity

Idaho and Washington specify that turbidity shall neither exceed 5 nephelometric turbidity units (NTU's) over background levels

when the background level is 50 NTU's or less nor have more than a 10 percent increase when background is more than 50 NTU's.

In Idaho, this applies to small public water intakes and the increase is not to exceed 25 NTU's. For protection of aquatic life, Idaho

Department of Environmental Quality (Idaho DEQ) specifies that instantaneous turbidity increases shall not be greater than 50

NTU's above background or greater than 25 NTU's above background for more than 10 consecutive days. Oregon Department of

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Environmental Quality (Oregon DEQ) simply specifies the 10 percent increase criterion (BNA, 1991).

3.9.1.3 Dissolved Oxygen

Dissolved oxygen standards vary for each state. Idaho DEQ has specific criteria below existing dams. From June 15 to October 15,

these criteria are set at 6.0 parts per million (ppm) [6.0 milligrams per liter (mg/L)] (30-day mean), 4.7 ppm (4.7 mg/L) (7-day mean

minimum), 3.5 ppm (3.5 mg/L) (instantaneous minimum), and 6 ppm (6 mg/L) or 90 percent of saturation (whichever is greater) for

salmonid spawning uses. Oregon DEQ specifies for cool-water aquatic life that dissolved oxygen concentrations shall not fall below

6.5 ppm (6.5 mg/L) as a minimum monthly mean or 5.0 ppm (5.0 mg/L) as a 7-day minimum mean, and shall not fall below 4.0 ppm

(4.0 mg/L) at any time. For Washington Class A waters, dissolved oxygen concentrations shall exceed 8.0 ppm (8.0 mg/L).

Washington Department of Ecology has listed the lower Snake River impaired by low dissolved oxygen under the provisions and

pursuant to Section 303(d) of the Clean Water Act.

3.9.1.4 Temperature

Each state has different thermal criteria. Idaho DEQ specifies the criteria in relation to specific use categories. Idaho DEQ’s

maximum instantaneous temperature standard for the Snake and Clearwater rivers is 72 °F (22 °C). The most restrictive use

criterion is for salmonid spawning, with maximum water temperatures set at 55 °F (13 °C) with daily averages no greater than 48.2

°F (9 °C) for the Clearwater River from RM 0 - RM 15.

Oregon DEQ set their temperature standard for the Columbia River in 1994. The current standard allows no water temperature

increases in the Columbia River, outside of an assigned mixing zone, when the stream water temperature is at or above 68 °F (20

°C). When the river is 67.5 °F (19.7 °C) or less, the Oregon state standard dictates that no more than a 0.5 °F (0.28 °C) increase is

allowed due to a single-source discharge. No more than a 2 °F (1.1 °C) increase is allowed by all sources when the stream is 66 °F

(19 °C) or less.

In Washington State, for most Class A waters, no increase over 64 °F (18 °C) due to human activity is allowed. However, for specific

Class A water classifications such as the lower Columbia and Snake Rivers, higher temperatures of 68 °F (20 °C) are allowed. In the

lower Columbia River and the Snake River above the confluence with the Clearwater River (RM 139.3), no increase over 0.54 F (0.3

°C) caused by human activity can occur from a single source, or no increases over 2 °F (1.1 °C) from all activities when the stream

is over 68 °F (20 °C). In the Snake River below the confluence with the Clearwater River, the 2 °F (1.1 °C) restriction is dropped in

favor of no temperature increase exceeding t = 34/(T+9) °C where t = change in temperature and T = background temperature.

3.9.1.5 Total Maximum Daily Loads

Region 10 EPA will develop total maximum daily loads (TMDLs) for thermal loading for the Pacific Northwest (Oregon, Washington,

and Idaho). The TMDLs will be completed in 2002 according to the planned schedule. The EPA has the lead on this regional project

due to the scope of the work, size of the basin, and the tremendous technical resources needed to complete the tasks. The Tribes,

States, and Canada will be in consultation with the EPA and will be cooperating agencies in the effort to complete this task on

schedule.

3.9.1.6 pH

Standards for pH vary among states, use classifications, and river system reaches. The Washington state standard pH levels range

between 6.5 and 8.5 pH, which are the pH units required for the protection of aquatic life and beneficial/domestic use. Oregon state

standard pH levels range between 7.0 and 8.5 for Columbia RMs 247 through 309. Umatilla and Walla Walla Basin streams range

from 6.5 to 9.0.

The water quality criteria presented in this document were compiled from the following sources:

National Recommended Water Quality Criteria (EPA, 1998b)

1999 Update of Ambient Water Quality Criteria for Ammonia (EPA, 1999)

Oregon Water Quality Criteria (ODEQ, 1998)

Washington State Water Quality Standards for Surface Waters (Ecology, 1997b)

Quality Criteria for Water (EPA, 1986)

United Nations Agricultural Water Quality Goals (NAS and NAE, 1972)

3.9.1.7 Background

Water quality conditions in the lower Snake, Clearwater, and Columbia River are presented in the following sections. Detailed data

for the proposed dredging and disposal locations are presented in appendix H.

For future water quality sampling and analysis associated with the proposed dredging and dredged material disposal, the Corps

plans to analyze for the parameters summarized in table 3-12 at a minimum. The tests and analysis methods used would be

reevaluated after completion of the Mid-Columbia and Lower Snake Region Sediment Testing Framework. Some additional water

quality analysis for organic chemicals may be recommended by the Testing Framework as it develops.

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Table 3-12

Test Description and Method

Test Description Test Method

Metals in water by ICP (Parameters are sampled as directed by the current of the

Regional Testing Framework for the NWW management units. EPA 6020

Calcium and Magnesium by ICP EPA 6020

Hardness by Titration EPA 130.2

Ammonia Nitrogen EPA 350.1

Nitrate/Nitrite Nitrogen EPA 353.2

Total Nitrogen TN EPA 350.1

Total Phosphorus EPA 365.4

Sulfate EPA 375.2

Chloride EPA 9251

Fluoride EPA 340.3

Silica EPA 370.1

Sodium and Potassium EPA 7010

TVS EPA 160.1

Orthophosphate EPA 365.4

Source: U.S. Army Corps of Engineers, Walla Walla District

3.9.1.8 Lower Snake River Water Quality

Within the study area, the water quality of the Snake River varies depending upon the location. A Corps study (Corps, 1999)

recorded water quality data for 12 sampling stations along the lower Snake River, 1 sampling station along the Clearwater River

near Lewiston, and 2 sampling stations on the Columbia River between McNary Dam and the confluence of the Snake and

Columbia Rivers.

3.9.1.8.1 Turbidity

Turbidity is an expression of the optical property that causes light to be scattered and absorbed rather than transmitted through the

water sample. Turbidity in water is caused by a colloidal or suspended matter composition of very fine organic and inorganic matter,

clays, microorganisms, and plankton. The standard unit of measurement is the nephelometric turbidity unit (NTU), which references

the type of instrument calibrated to measure the property. Correlation of turbidity with total suspended solids (TSS) is problematic

due to differences in size, shape, and refractive indexes affecting the light scattering of a suspension. The cause and effect

relationship to the aquatic environment is directly related to suspended matter blocking light. Although turbidity is not directly

related to the amount of TSS, it can be used as an index of the amount of TSS in the water column (i.e., the higher the turbidity, the

gr eater the amount of TSS).

Turbidity is often confused with the particle mass density measurement TSS. Suspended particle or sediment load is composed of

fine particles consisting primarily of inorganic materials of sufficient size and mass to settle quickly when kinetic energy (flow)

decreases enough for the mass of the particle to fall out of suspension. The literature suggests there are direct correlations between

suspended sediment load and fish feeding. Lloyd (1985) lists several studies spanning three decades where increased sediment

load results in decreases of salmonid feeding. Noggle (1978) looked at the physiological effects to gill tissue in salmon exposed to

high loads of suspended sediment. Most of the conclusions were that the fish only had damaged gills when extreme quantities of

sediment were suspended in test waters. He also concluded that feeding was most affected in the moderate and lower levels of

suspended particles and turbidity.

The use of mixing zones in monitoring and enforcement of TSS and turbidity standards seeks to accommodate the temporal

suspension effects of larger size particles. While a consistent relationship between turbidity measurements and TSS concentration

may not exist, the impacts caused by high levels of the suspended particles can be predicted by turbidity, which is easily measured.

The practicality of rapid measurement of suspended sediment quantity by drying at constant temperature followed by precision

weighing is difficult at best. The ease and accuracy for which turbidity can be measured in the field has prompted many regulators

to develop turbidity criteria instead of suspended sediment criteria.

Turbidity was lowest at the confluence of the Snake and Clearwater Rivers and increased farther downstream in the Snake River.

Median turbidity values ranged from 2 to 4 NTU's in the Snake River (Corps, 1999). It shall be noted that, during the sampling for

this study, periods of heavy runoff or heavy storm non-point source water discharge were not analyzed for physical parameters such

as turbidity. In some instances, samples were not analyzed due to safety constraints required when operating small watercraft.

3.9.1.8.2 Dissolved Oxygen

Dissolved oxygen values throughout the Snake River ranged from 6.4 to 13.3 ppm (6.4 to 13.3 mg/L) above Idaho’s 6.0 ppm (6.0

mg/L) minimum standard (Corps, 1999). Trend analysis suggests the dissolved oxygen concentrations are linked to flow and

temperature effects. In the spring, fall, and winter months, the dissolved oxygen concentration is generally within the Idaho and

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Oregon water quality standards. In the summer months where there is reduced flow and increased temperature, low dissolved

oxygen is found in the slack water areas of the dam forebay and sloughs. By Washington State Standard for Class A water,

dissolved oxygen is a significantly limited water quality parameter. Washington State, in accordance to the provisions set by Section

303(d) of the Clean Water Act, lists the Snake River as limited for dissolved oxygen.

Differences in dissolved oxygen concentrations were small between surface waters and waters near sediments for most of the year.

Differences were less than 1 ppm (1 mg/L) between top and bottom waters in deep-water reservoirs according to the Corps (1999)

study. Although the general dissolved oxygen trend of the five reservoirs is similar to the previous discussion, there were exceptions

recorded in the beginning of September in the Lower Granite and Little Goose reservoirs where differences were measured at 2.5,

3.8, and 5.6 ppm (2.5, 3.8, and 5.6 mg/L) at three separate sampling sites (Corps, 1999).

3.9.1.8.3 Water Temperature

Water temperature in the study area varies by time of year and location. Generally, water temperature is lower in the winter months

of January and February, increases slowly during spring runoff (March - May), increases more rapidly in late spring until

mid-summer (June - early August), plateaus through mid-September, then decreases steadily through January (table 3-13). For

example, at the Lower Granite tailrace in water year 2000 (October 1999 to September 2000), the average monthly water

temperatures in January and February were 39.0 and 39.4 "F (3.9 and 4.1 "C) with a maximum daily temperature of 41.4 "F (5.2 "C)

and a minimum daily temperature of 37.2 °F (2.9 °C). Conversely, average monthly temperatures in July through September in 2000

were 66.0, 64.9, and 65.1 °F (18.9, 18.3 and 18.4 °C), respectively. The maximum daily value for this period was 68.0 °F (20.0 °C)

and the lowest was 61.9 °F (16.6 °C). Water temperatures in the Ice Harbor tailrace were comparable to Lower Granite; however, Ice

Harbor was warmer on average throughout the year (table 3-14). Because temperatures were similar at the farthest extents of the

study area, data for the other Snake River reservoirs were assumed to follow similar trends. Average daily variation refers to the

difference between maximum and minimum temperatures on a daily basis and averaged for the month designated.

Table 3-13

Lower Granite Tailrace Temperature Data for Water Year 2000

Monthly Average Daily Max Daily Min

Average

Daily Variation

October 58.3 °F (14.6 °C) 63.3 °F (17.4 °C) 53.2 °F (11.8 °C) 0.4 °F (0.2 °C)

November 50.2 °F (10.1 °C) 58.2 °F (11.8 °C) 46.0 °F (7.8 °C) 0.4 °F (0.2 °C)

December 42.6 °F (5.9 °C) 46.0 °F (7.8 °C) 40.6 °F (4.8 °C) 0.4 °F (0.2 °C)

January 39.0 °F (3.9 °C) 40.1 °F (4.5 °C) 37.9 °F (3.3 °C) 0.2 °F (0.1 °C)

February 39.4 °F (4.1 °C) 41.4 °F (5.2 °C) 37.2 °F (2.9 °C) 0.4 °F (0.2 °C)

March 43.7 °F (6.5 °C) 47.3 °F (8.5 °C) 41.4 °F (5.2 °C) 0.4 °F (0.2 °C)

April 49.3 °F (9.6 °C) 52.3 °F (11.3 °C) 46.2 °F (7.9 °C) 0.7 °F (0.4 °C)

May 53.6 °F (12.0 °C) 57.0 °F (13.9 °C) 50.7 °F (10.4 °C) 0.5 °F (0.3 °C)

June 59.7 °F (12.0 °C) 66.0 °F (13.9 °C) 53.6 °F (10.4 °C) 0.9 °F (0.4 °C)

July 66.0 °F (18.9 °C) 68.0 °F (20.0 °C) 63.9 °F (17.7 °C) 0.9 °F (0.9 °C)

August 64.9 °F (18.3 °C) 57.3 °F (19.6 °C) 61.9 °F (16.6 °C) 1.4 °F (0.8 °C)

September 65.1 °F (18.4 °C) 67.5 °F (19.7 °C) 62.1 °F (16.7 °C) 0.7 °F (0.4 °C)

Source: Corps Northwest Division CROMES database (Walla Walla TDGMS)

Table 3-14

Ice Harbor Tailrace Temperature Data for Water Year 2000

Monthly Average Daily Max Daily Min

Average

Daily Variation

October 61.5 °F (16.4 °C) 66.7 °F (19.3 °C) 56.1 °F (13.4 °C) 3.2 °F (1.8 °C)

November 54.0 °F (12.2 °C) 58.6 °F (14.8 °C) 49.5 °F (49.5 °C) 2.7 °F (2.7 °C)

December 47.3 °F (8.5 °C) 51.6 °F (10.9 °C) 41.7 °F (5.4 °C) 3.2 °F (1.8 °C)

January 40.3 °F (4.6 °C) 44.6 °F (7.0 °C) 37.9 °F (3.3 °C) 1.8 °F (1.0 °C)

February 39.7 °F (4.3 °C) 42.8 °F (6.0 °C) 38.1 °F (3.4 °C) 1.4 °F (0.8 °C)

March 44.8 °F (7.1 °C) 49.3 °F (9.6 °C) 40.6 °F (4.8 °C) 2.9 °F (1.6 °C)

April 51.3 °F (10.7 °C) 54.1 °F (12.3 °C) 45.7 °F (7.6 °C) 2.7 °F (1.1 °C)

May 56.3 °F (13.5 °C) 63.3 °F (17.4 °C) 52.0 °F (11.1 °C) 3.1 °F (1.7 °C)

June 61.7 °F (16.5 °C) 67.5 °F (19.7 °C) 57.0 °F (13.9 °C) 3.2 °F (1.8 °C)

July 69.4 °F (20.8 °C) 72.9 °F (22.7 °C) 63.3 °F (17.4 °C) 3.6 °F (2.0 °C)

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August 69.1 °F (20.6 °C) 72.9 °F (22.7 °C) 63.3 °F (17.4 °C) 6.8 °F (2.0 °C)

September 67.1 °F (19.5 °C) 71.2 °F (21.8 °C) 62.8 °F (17.1 °C) 3.8 °F (2.1 °C)

Source: Corps Northwest Division CROMES database (Walla Walla TDGMS)

Temperatures measured at the USGS gage at Anatone (Snake RM 167.2) give some indication of the Snake River water

temperature in the Lewiston area. These temperatures range from an average maximum of about 37.4 °F (3 °C) in February to about

72.5 °F (22.5 °C) in mid-July (Corps, 1999). In addition, in water year 2000, the lowest daily maximum temperature of 41.0 °F (5 °C)

and lowest daily minimum of 36.5 °F (2.5 °C) were both recorded in January. Conversely, the highest maximum temperature of 75.7

°F (24.3 °C) and highest minimum temperature of 66.6 °F (19.2 °C) occurred in August (table 3-15). Although the Anatone station

reflects the warm water from the Snake River above the confluence, it does not show the cooling influence that Dworshak releases

have on the Lower Granite reservoir.

Table 3-15

Snake River at Anatone, Temperature Data for Water Year 2000

Monthly Average Daily Max Daily Min

Average

Daily Variation

October 63.5 °F (17.5 °C) 52.7 °F (11.5 °C) 1.4 °F (0.8 °C)

November 53.6 °F (12.0 °C) 43.7 °F (6.5 °C) 0.9 °F (0.5 °C)

December 46.4 °F (8.0 °C) 38.3 °F (3.5 °C) 0.9 °F (0.5 °C)

January 41.0 °F (5.0 °C) 36.5 °F (2.5 °C) 0.7 °F (0.4 °C)

February 43.7 °F (6.5 °C) 37.4 °F (3.0 °C) 0.9 °F (0.5 °C)

March 46.0 °F (7.8 °C) 48.6 °F (9.2 °C) 43.7 °F (6.5 °C) 1.6 °F (0.9 °C)

April 51.4 °F (10.8 °C) 55.4 °F (13.0 °C) 46.9 °F (8.3 °C) 1.8 °F (1.0 °C)

May 55.8 °F (13.2 °C) 60.3 °F (15.7 °C) 52.2 °F (11.2 °C) 1.8 °F (1.0 °C)

June 62.2 °F (16.8 °C) 70.0 °F (21.1 °C) 53.8 °F (12.1 °C) 2.2 °F (1.2 °C)

July 70.0 °F (21.1 °C) 74.8 °F (23.8 °C) 64.6 °F (18.1 °C) 2.2 °F (1.2 °C)

August 71.1 °F (21.7 °C) 75.7 °F (24.3 °C) 66.6 °F (19.2 °C) 3.4 °F (1.9 °C)

September 66.2 °F (19.0 °C) 74.7 °F (23.7 °C) 55.2 °F (12.9 °C) 3.2 °F (1.8 °C)

Source: Corps Northwest Division CROMES database (Walla Walla TDGMS)

3.9.1.8.4 pH

Values measured in the upper reaches of the lower Snake River averaged slightly above 8 pH units. The average pH for the lower

portion of the lower Snake River was slightly lower than 8 pH units (Corps, 1999). On a significant number of occasions, the pH

exceeded 8.0 and was at 8.5 or higher. The lower Snake River is consistently observed under a variety of conditions to maintain

alkaline conditions between 7.8 and 8.6 for a significant number of days throughout the year. Natural geological conditions and

artificial conditioning of the soil realistically contribute to the raised pH. The effects of higher pH exacerbate the ammonia problems

encountered in most of the sediment management areas. This is further explained in the nutrients section covering un-ionized

ammonia.

3.9.1.8.5 Nutrients

Most of the studies dealing with sediment quality referenced in this document describe the sediment as very rich in nitrogenous

compounds. The dominant species of nitrogen in the sediment is ammonia. In the water, nitrite/nitrate (NO2 + NO3) is the dominant

species of nitrogen if the water is well oxygenated and the proportion of nitrite is small. Nitrite is an intermediate oxidation state of

nitrogen, which can be in the form of nitrate, nitrite, or ionized (NH4) and un-ionized ammonia (NH3) depending on oxidation state.

The Snake River sediments are very rich with nutrients and contain high amounts of ammonia [60 to 80 ppm (60 to 80 mg/L)

average] but it is not fully understood how the nitrogen cycle works in the Snake River reservoirs. The lower Snake River had

average water nitrite/nitrate levels from 0.13 to 0.35 ppm (0.13 to 0.35 mg/L). The water ammonia levels were near instrument

detection limits in some cases or below detection limit [0.007 ppm (0.007 mg/L) N as NH3]. This suggests the ammonia is probably

bound to the sediments. Unless it is exposed, the small amount of ammonia that is naturally released is generally oxidized quickly.

Ammonium (NH4+) is the ionized form of ammonia and is generally only toxic in very high concentrations. It is the un- ionized portion

of ammonia (NH3) that is toxic to aquatic life (Downing and Merkens, 1955). Un-ionized ammonia is more toxic because it is a neutral

molecule and, thus, has the ability to diffuse across the epithelial membranes of aquatic organisms far more readily than a charged

ion. In nature, ammonia is a byproduct of the organism's biological processes and must be excreted. High external un-ionized

ammonia concentrations reduce or reverse diffusive gradient and cause the buildup of ammonia in gill tissue of fish (EPA, 1999).

Research on various forms of aquatic life indicates that un-ionized ammonia toxicity positively correlated to temperature (Nimmo et

al., 1989) and pH (Tabata, 1962; Armstrong, 1978), especially in hard water (Johnson, 1995).

There is a potential for both acute (short-term exposure) and chronic (long-term exposure) effects from un- ionized ammonia in the

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Snake River (Corps, 1999). The Snake River has relatively hard water based on the concentration of calcium carbonate and

magnesium carbonate. Depending on the temperature, flow pattern, pH, and hardness, there could be toxic effects to aquatic life.

Performance of the work during the coldest months would help to minimize potential effects of ammonia. Close water quality

monitoring would ensure that any increases are short in duration and do not meet acute conditions.

During dredging, specific ion probes would be used to monitor ammonia concentration in the plume downstream of the dredging

areas and downstream of the disposal areas. Monitoring would include a detailed analysis of ammonia in the sediment and water

prior to dredging. If nitrogen in the sediments is fairly high [more than 35 ppm (35 mg/L)], elutriate testing would be necessary prior

to initiation of the dredging activity.

The dominant species of phosphorus is total phosphorus (TP) (Corps, 1999). The TP values in the lower Snake River ranged from

0.036 to 0.067 ppm (0.036 to 0.067 mg/L) TP as phosphate. The ortho-phosphate (ortho-P) in the lower Snake River ranged from

0.013 to 0.023 ppm (0.013 to 0.023 mg/L) ortho-P as phosphate. Phosphate is essential for plant growth and, when it is present with

other nutrients in abundance, it leads to substantial increases in algae growth. When this occurs, deleterious effects from nuisance

blooms of blue-green algae increase. Nuisance blooms of blue-green algae in the Snake River are generally described as large

mats of floating biological material with bubbles in it.

The lower Snake River water quality has degraded significantly by increased nutrient loading since 1974 (Greene, 1995). Greene

(1995) determined growth potentials in 1995 Snake River samples were so large that test algae could not reach nitrogen or

phosphorus limitation without the assistance of EDTA (Ethylendiamine tetraacetic acid disodium salt). No samples have been

analyzed during spring runoff periods of times of high flow. It is possible that a majority of the phosphorus loading occurs during

this time. River concentration of phosphorus in the sediment ranges from 34 to 38 ppm. Very little is understood about the

phosphorus budget of the reservoirs. Small releases of phosphorus should not pose a problem. During dredging, water and

sediment samples for phosphorus would be analyzed to determine potential for environmental harm.

3.9.1.8.6 Salinity/Conductivity

Salinity is the amount of dissolved material in water. For comparison purposes, fresh water is approximately 4 to 8 percent of the

salt ionic strength of seawater. Fresh water concentration of dissolved ions is generally between 100 to 200 ppm (100 to 200 mg/L).

The ionic composition of fresh waters is dominated by dilute solutions of compounds, particularly bicarbonates, sulfates, and

chlorides, which are dissolved as water percolates through soil, flows down a channel, or is otherwise in contact with naturally

occurring geologic deposits. Other factors such as the release of pollutants, storm water runoff, and windblown dusts can increase

salinity of a body of water. Because the entire dredging and disposal action occurs in fresh water only, this section and later

sections discuss salinity by its qualitative scale of measurement referred to as specific conductivity. Because it is not the appropriate

unit of measure for the quantitative measurement of salinity, conductivity cannot be a direct relationship to salinity in fresh water.

Conductivity measures the ability of a compound in an aqueous solution to exhibit electrical current conductance.

In 1997, the average conductivity in the lower Snake River from RM 6 to RM 129 ranged from 68 microhms to 363 microhms.

Re-suspension of sediments can put more of the major dissolved ions into solution and can cause an increase in salinity.

Freshwater biota not accustomed to changes in dissolved salt concentration could be negatively impacted by such changes

because they lack the capacity to osmoregulate in even small increases of salinity. Identification of baseline salinity and estimation

of potential change is difficult in the absence of adequate data. The Corps plans to collect quantitative data on salinity changes to

assess the potential for negative impacts to freshwater biota.

3.9.1.8.7 Water Quality Chemicals of Concern

Although water quality sampling for conventional parameters, such as pH and temperature, has been conducted within numerous

areas of the lower Snake River, recent sampling data for water quality chemicals of concern are not available. However, sampling of

sediments for chemicals of concern has been undertaken and is discussed in Section 3.9.2.4. Elutriate testing (mixing sediments with

water to measure containments can potentially affect water quality) is used to determine potential impacts of sediments on water

quality. The only available water quality data on potential chemicals of concern for the proposed dredging areas is from the Water

Quality Report, Lower Granite Lock and Dam Snake River, Washington - Idaho, which was published in 1973 and summarized data

collected between 1969 and 1971 before Lower Granite was built. The metals copper and iron were found in three water quality

sampling stations. At Snake RM 135, the average copper concentration was 0.12 ppm (0.12 mg/L) and the average iron

concentration was 0.08 ppm (0.08 mg/L).

3.9.1.9 Columbia River Water Quality

The entire Columbia River Basin encompasses a 259,000-square- mile (670 807-km2) area. There is no authoritative description of

overall water quality conditions in the basin, in part, because two nations and six states share the basin. Each state has unique

water quality standards, management programs, and monitoring programs. The following paragraphs discuss the Columbia River

between the Snake River confluence and McNary.

3.9.1.9.1 Turbidity

Median turbidity values ranged from 2 to 3 NTUs in the Columbia River between the confluence of the Snake and Columbia Rivers

and McNary (Corps, 1999), well below Washington’s 25-NTU background action limit.

3.9.1.9.2 Dissolved Oxygen

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Dissolved oxygen data is not available for the proposed dredging and disposal areas in the Columbia River. Water quality sampling

in the Snake River portion of McNary reservoir, just upstream of the confluence with the Columbia River (where dredging is

proposed) recorded dissolved oxygen concentrations ranging from 9.0 to 12.4 ppm (9.0 to 12.4 mg/L).

3.9.1.9.3 Water Temperature

Water temperature in the McNary tailrace for water year 2000 follows the same pattern exhibited by the Snake River reservoirs and

varies by time of year and location. Generally, water temperature is lower in the winter months of January and February, increases

slowly during spring runoff (March - May), increases more rapidly in late spring until mid summer (June - early August), plateaus

through mid-September, then decreases steadily through January (table 3-16). The average monthly temperatures in January and

February were 40.1 and 38.8 °F (4.5 and 3.8 °C), respectively. The average monthly temperatures in July and August were 66.2 and

69.3 °F (19 and 20.7 °C), respectively.

Table 3-16

McNary Tailrace Temperature Data for Water Year 2000

Monthly Average Daily Max Daily Min

Average

Daily Variation

October 59.0 °F (15.0 °C) 62.1 °F (16.7 °C) 54.3 °F (12.4 °C) 0.4 °F (0.2 °C)

November 52.3 °F (11.3 °C) 54.3 °F (12.4 °C) 48.9 °F (9.4 °C) 0.4 °F (0.2 °C)

December 45.7 °F (7.6 °C) 48.9 °F (9.4 °C) 42.6 °F (5.9 °C) 0.2 °F (0.1 °C)

January 40.1 °F (4.5 °C) 42.4 °F (5.8 °C) 37.9 °F (3.3 °C) 0.5 °F (0.3 °C)

February 38.8 °F (3.8 °C) 39.9 °F (4.4 °C) 37.9 °F (3.3 °C) 0.4 °F (0.2 °C)

March 42.3 °F (5.7 °C) 45.5 °F (7.5 °C) 39.4 °F (4.1 °C) 0.7 °F (0.4 °C)

April 48.7 °F (9.3 °C) 51.4 °F (10.8 °C) 44.8 °F (7.1 °C) 1.1 °F (0.6 °C)

May 54.7 °F (12.6 °C) 58.5 °F (14.7 °C) 50.4 °F (10.2 °C) 1.1 °F (0.6 °C)

June 60.4 °F (15.8 °C) 64.8 °F (18.2 °C) 56.5 °F (13.6 °C) 1.3 °F (0.7 °C)

July 66.2 °F (19.0 °C) 69.3 °F (20.7 °C) 63.7 °F (17.6 °C) 0.9 °F (0.5 °C)

August 69.3 °F (20.7 °C) 70.9 °F (21.6 °C) 67.6 °F (19.8 °C) 0.9 °F (0.5 °C)

September 65.7 °F (18.7 °C) 69.1 °F (20.6 °C) 62.1 °F (16.7 °C) 1.1 °F (0.6 °C)

Source: Corps, 2001

3.9.1.9.4 pH

The median pH value along the Columbia River between the Snake River confluence and McNary was 8.2 pH units (Corps, 1999).

As was discussed in the nutrients section, the higher the pH, the greater the potential for ammonia to exist in the un-ionized state.

This would directly impact fish and dredging windows and would contribute to the growing problem of sediment management in

McNary reservoir.

3.9.1.9.5 Nutrients

Currently, there is no information available on nutrients for McNary reservoir. Monitoring would be done during and after dredging in

the area to be dredged and, if any concerns arise, they will be addressed at that time.

3.9.1.9.6 Salinity/Conductivity

Currently, there is no information available on salinity or conductivity for McNary reservoir. Monitoring would be done during and

after dredging in the area to be dredged and, if any concerns arise, they will be addressed at that time.

3.9.1.9.7 Water Quality Chemicals of Concern

Water quality sampling data for potential chemicals of concern are not available for the areas of the Columbia River where dredging

and disposal are proposed. Additional sampling and analysis will be completed prior to dredging consistent with the Dredged

Material Evaluation Framework.

3.9.1.10 Clearwater River Water Quality

Data for the Clearwater River system are limited, although studies are being conducted that may provide useful information. The

Corps study (1999) had one sampling station on the Clearwater River that was within the study area. The Corps and USGS also

conduct water quality monitoring on the Clearwater River.

3.9.1.10.1 Turbidity

Turbidity in the Clearwater River had a median value of 2 NTU's (Corps, 1999).

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3.9.1.10.2 Dissolved Oxygen

Dissolved oxygen values in the Clearwater River ranged from 8.8 to 12.1 ppm (8.8 to 12.1 mg/L) (Corps, 1999).

3.9.1.10.3 Water Temperature

Temperatures measured at the USGS gage at Spalding (Clearwater RM 11.6) give some indication of the Clearwater River water

temperature in the Lewiston area. In water year 2000, the lowest daily maximum temperatures of 41.9 °F (5.5 °C) and the lowest

daily minimum temperature of 35.6 °F (2.0 °C) were recorded in January. Conversely, the highest maximum temperature of 67.3 °F

(19.6 °C) occurred in June and highest minimum temperature of 53.6 °F (12.0 °C) occurred in July (table 3-17).

Table 3-17

Clearwater River at Spalding, Temperature Data for Water Year 2000

Monthly Average Daily Max Daily Min

Average

Daily Variation

October 55.4 °F (13.0 °C) 45.5 °F (7.5 °C) 3.6 °F (2.0 °C)

November 50.9 °F (10.5 °C) 40.1 °F (4.5 °C) 2.0 °F (1.1 °C)

December 43.7 °F (6.5 °C) 36.5 °F (2.5 °C) 1.1 °F (0.6 °C)

January 41.9 °F (5.5 °C) 35.6 °F (2.0 °C) 2.0 °F (1.1 °C)

February 43.7 °F (6.5 °C) 37.4 °F (3.0 °C) 2.0 °F (1.1 °C)

March 44.6 °F (7.0 °C) 48.6 °F (9.2 °C) 41.2 °F (5.1 °C) 3.4 °F (1.9 °C)

April 46.4 °F (8.0 °C) 50.5 °F (10.3 °C) 43.3 °F (6.3 °C) 2.5 °F (1.4 °C)

May 50.5 °F (10.33 °C) 56.8 °F (13.8 °C) 45.7 °F (7.6 °C) 2.3 °F (1.3 °C)

June 57.6 °F (14.2 °C) 67.3 °F (19.6 °C) 49.3 °F (9.6 °C) 3.1 °F (1.7 °C)

July 57.2 °F (14.0 °C) 62.6 °F (17.0 °C) 53.6 °F (12.0 °C) 4.5 °F (2.5 °C)

August 55.0 °F (12.8 °C) 62.1 °F (16.7 °C) 50.7 °F (10.4 °C) 4.9 °F (2.7 °C)

September 57.7 °F (14.3 °C) 64.9 °F (18.3 °C) 50.5 °F (10.3 °C) 4.1 °F (2.3 °C)

3.9.1.10.4 pH

The median value for pH in the Clearwater River was 7.7 pH units (Corps, 1999).

3.9.1.10.5 Nutrients

Phosphorus is a key metabolic nutrient. Nitrogen is an important plant nutrient. Ionic concentrations of these nutrients are evaluated

because elevated concentrations can indicate overenrichment and pollution of natural waters. Ortho-P values ranged from 0.001 to

0.006 ppm (0.001 to 0.006 mg/L) and TP ranged from 0.006 to 0.017 ppm (0.006 to 0.017 mg/L). The nitrate/nitrite ranged from 0.02

to 0.05 ppm (0.02 to 0.05 mg/L). Total ammonia nitrogen was below detection limits most of the time. Total nitrogen ranged from

0.07 to 0.14 ppm (0.07 to 0.17 mg/L). This indicates the water that flows from the Clearwater River to the Snake River does not

contribute to the nutrient loading of the Snake River. Significant portions of the waters that flow in the lower Clearwater River come

from Dworshak reservoir, which is a deep reservoir characteristically low in nutrients.

3.9.1.10.6 Salinity/Conductivity

Currently, there is no information on salinity or conductivity for the portion of the Clearwater River included in the study area.

Conductance ranged from 15 to 49 μS/cm.

3.9.1.10.7 Water Quality Chemicals of Concern

The only available water quality data on potential chemicals of concern for the proposed dredging areas in the Clearwater River is

from the Water Quality Report, Lower Granite Lock and Dam Snake River, Washington – Idaho, which was published in 1973 and

summarized data collected between 1969 and 1971 before Lower Granite was built. It should be noted that these data are of very

limited utility in describing the water quality conditions of the Clearwater River.

At Clearwater RM 2.3, copper concentrations were 0.08 ppm (0.08 mg/L) and iron concentrations were 0.21 ppm (0.21 mg/L).

3.9.2 Sediment Quality

The Snake River carries large quantity sediment loads probably due in large part to soil erosion from agricultural and forestry

practices. The Snake River flows through an area dominated by agricultural use and the sediments tend to be highly enriched with

organic nitrogen compounds and other nutrients. The sediments have small amounts of herbicides and pesticides, low levels of

dioxin, and few heavy metals.

The Corps sampled more than 85 sites in McNary, Ice Harbor, Little Goose, Lower Monumental, and Lower Granite reservoirs for the

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Lower Snake River Juvenile Salmon Migration Feasibility Study. The data availability for each site is highly dependent upon the local

dredging requirements, contaminants of concern, and fiscal year funding issues. The past parameters for sediment sampling

included the following:

Glyphosates

Herbicides

Elutriate herbicides

Manganese

Metals

Ambient metals

Organic pesticides

Particle size

Elutriate pesticides

Pesticides

Petroleum products

Nutrient

Elutriate nutrients

Available sediment data from the proposed dredging and disposal locations are summarized in appendix H. These tables are

excerpted from the Corps’ sediment database. Figures with the sediment sample location sites are also shown in appendix H. The

list of individual compounds to be tested is reviewed at least every 3 years. Individual compounds are included or dropped from the

list based on their use in the area.

3.9.2.1 Sediment Quality Criteria and Standards

There are no uniform freshwater sediment quality criteria that provide a definitive numerical standard. The EPA and some states and

Tribes are currently in the process of developing standards. However, to date, there have been several research and guidance

documents that provide "screening" or recommended values for constituents found in sediment. These values are to be used as a

benchmark or to indicate a potential concern. The sources that provide some of the numerical le vels of guidance are as follows:

Washington Department of Ecology. 1997. Creation and Analysis of Freshwater Sediment Quality Values in Washington

(Publication No. 97-323a). (Ecology, 1997a)

U.S. Army Corps of Engineers. 1998. Dredged Material Evaluation Framework: Lower Columbia River Management Area.

(Corps, 1998)

U.S. Environmental Protection Agency. 1997. National Sediment Quality Survey. Appendix D. (Publication No. 832-R-97-006).

(EPA, 1997)

U.S. Environmental Protection Agency. 1993. Technical Basis for Deriving Sediment Quality Criteria for Non- ionic Organic

Contaminants for Protection of Benthic Organisms (Publication No. 822-R-93-011). (EPA, 1993)

U.S. Environmental Protection Agency. 1991. Evaluation of Dredged Material Proposed for Ocean Disposal Testing Manual

(Publication No. 503/8-91/001). (EPA, 1991)

The marine standards found in the EPA Ocean Testing Manual and the Corps Dredged Material Evaluation Framework were used in

the past to screen freshwater sediment. Use of this criterion is of limited value to determine safety levels in fresh water and should

only be used when developing consensus-based measures.

These minimum screening criteria are recommended in the Evaluation of Dredged Material Proposed for Discharge in Waters of the

U.S. - Inland Testing Manual (ITM), an EPA/Corps guidance document. The protocols in the manual are intended solely as uniform

guidance for testing of dredged material in fresh water. It is still the requirement of the permitted dredging entity to assess and

document the potential for contaminant-related impacts associated with dredged material disposal. The manual does not alter the

statutory and regulatory Combined Federal Code requirements for permitting decisions under Section 404 of the Clean Water Act.

Under the Clean Water Act regulations, the testing is conducted in order to assist the permitting authority in making factual

determinations regarding the effect of the discharge on the aquatic ecosystem and in the determination whether the discharge will

comply with the 404(b)(1) guidelines.

The 404(b)(1) guidelines provide the substantive environmental criteria used in evaluating proposed discharges of dredged or fill

material into waters of the United States. Fundamental to these guidelines is the precept that dredged or fill material should not be

discharged into the aquatic ecosystem unless it can be demonstrated that such a discharge would not have an adverse impact

either individually or in combination with known and/or probable impacts of other activities affecting the ecosystems of concern.

The ITM does not provide quantitative guidance on interpreting the ecological meaning of such effects (e.g., the ecological

consequences of a given tissue concentration of a bio-accumulated contaminant or the consequences of that body burden to the

animal). Dredged material bioassays (toxicity and bioaccumulation tests) are subject to interpretation and are not precise predictors

of environmental effects. Rather, the manual considers statistically significant increases above certain levels compared to the

reference sediment as potentially undesirable. Because a statistically significant difference is not a quantitative prediction that an

ecologically important impact would occur in the field, this document discusses some of the additional factors to be weighed in

evaluating potential ecological impact. The site-specific information and procedures found in the ITM are more likely to result in

environmentally sound evaluations than is reliance on statistical significance alone.

Given the limitations of existing framework documents noted above, the Corps is developing a Mid-Columbia and Lower Snake

Region Sediment Testing Framework. An outline for this framework is presented in appendix J. The regional framework will not be

completed prior to initiation of the proposed dredging and dredged material management activities documented in this DMMP/EIS.

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In the interim, the Dredged Material Evaluation Framework: Lower Columbia River Management Area will be used by the Corps to

evaluate the suitability of dredged material for in-water disposal. The procedures in the Lower Columbia Framework will be used and

evaluated for their applicability for adoption in the Mid-Columbia and Lower Snake Region Framework.

3.9.2.2 Grain Size

The Corps took sediment samples from the Snake/Clearwater Rivers confluence dredging areas in September 1997 and from port

facilities in McNary reservoir in 1998 for grain size analysis. The results recorded grain sizes ranging from 3.9 to 5.7 micrometers

(μm) (Battelle, 1992). Most sediment samples taken for previous dredging operations have contained between 85 and 90 percent

sand with 10 to 15 percent silt and fines. These samples are indicative of material that might be dredged from the main navigation

channel. Composition of dredged materials from the port areas, close to streambanks, and in boat basins is expected to contain up

to 50 percent silt and fines. This would be consistent with the results found in 1996 along the shoreline at the Port of Lewiston. See

table 3-18 for grain size distribution throughout the Snake River. Grain sizes in table 3-18 are presented in American Society for

Testing and Materials (ASTM) E11-70 standard sieve units. These units correspond inversely to particle size. For example, sieve size

of less than five would indicate particle size of greater than 4.0 mm; sieve size of greater than 230 would indicate very fine materials,

less than 0.063 mm in diameter. Dredging at the navigation lock approaches is expected to be comprised of predominantly river

cobbles and rock.

Table 3-18

Percent of Sample by Grain Size (ASTM Standard Sieve)

Reservoir <5S 5S 5S10S

10S20S20S40S40S60S60S140S140S200S200S230S >230S

Ice Harbor 2 0 0 1 18 18 23 0 33 5

Lower Monumental 3 1 1 1 3 7 13 0 70 1

Little Goose 2 1 4 3 10 12 16 0 50 3

Lower Granite 0 0 1 2 7 17 20 1 50 2

McNary 0 0 3.97 0.48 1.2 3.81 15.74 7.69 8.36 58.95

Source: U.S. Army Corps of Engineers, Walla Walla District

Dredging the navigation channel downstream of the dams should have little effect on water quality since the material to be removed

is expected to be river cobbles with some larger rocks with very small quantities of fines. In-water placement of this material is

expected to have little impact, but could create a small local turbidity plume (Battelle, 1992).

3.9.2.3 Sediment Chemicals of Concern

Sediment core samples have been taken along the lower Snake River . Appendix H shows the sediment sampling site locations that

are in dredging and disposal areas. The samples were analyzed for sediment quality and ambient elutriate quality. Summary tables

of the sediment quality data for the dredging and disposal areas are also located in appendix H. The results are discussed below.

Sediment samples were tested for the following organic compound groups: chlorinated herbicides, dioxins, glyphosate herbicide,

organochlorine pesticides, organophosphorus pesticides, semi- volatile compounds, and total petroleum hydrocarbons. Each of the

samples was analyzed for a suite of 18 metals (inorganic). The metals analyzed included arsenic, barium, beryllium, cadmium,

chromium, cobalt, copper, lead, manganese, mercury, molybdenum, nickel, selenium, silver, strontium, thallium, vanadium, and

zinc. For each of the sediment samples, an ambient elutriate was prepared and analyzed for organophosphorus pesticides,

organochlorine pesticides, and metals. Samples were also tested for nutrient concentrations.

Selection of potential chemicals of concern was conducted through an initial screening comparison between the collected data with

their respective water quality and sediment quality values. The purpose of the screening process was to identify chemicals of

potential concern that exceed their minimum water or quality values. The overall process involved comparing the maximum detected

concentration for each chemical in each matrix (or one- half the maximum detection limit for chemicals not detected in any sample)

with the minimum appropriate and applicable water or sediment quality criteria. Chemicals present in concentrations exceeding the

respective criteria were then considered for further evaluation. (See section 3.9.2.4, below.) This is a very conservative screen

because maximum concentrations under existing conditions would likely overestimate actual exposure concentrations. Nevertheless,

this process would be expected to screen out most compounds and focus the evaluation on relatively few chemicals of potential

concern.

Sediment core samples were also taken from port facilities in McNary reservoir. These samples were analyzed for the same metals

as the Snake River except for arsenic. No ambient elutriate analysis was conducted for these samples.

3.9.2.4 Sediment Quality

Based on screening comparisons of chemicals in sediments with their respective sediment quality criteria, only nutrients,

manganese, total dichlorodiphenyltrichloroethane (DDT) (which is calculated from the sum of 4,4-DDT, 4,4-DDD, and 4,4-DDE), and

dioxin TEQ (toxic equivalency quotient) exceeded their minimum sediment quality criteria and are considered chemicals of concern

(Corps, 1999). Concentrations of all other individual chemicals (or one-half of the detection limit for chemicals not detected) were

below their respective criteria.

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Sediment samples were taken from seven sites along the dredging locations of the Lower Granite reservoir and the Little Goose

reservoir. These seven samples were tested for ammonia and nitrate. At these sampling sites, the maximum level of ammonia was

110 milligrams per kilogram (mg/kg) and the average ammonia level was 81 mg/kg. The average nitrate level was 0.5 mg/kg and the

maximum level measured was 0.8 mg/kg.

The sediment analysis for McNary detected low levels of all the tested metals except for mercury. No mercury was detected in

sediments during this 1973 study in Oregon. Most existing sediment quality data is based upon sampling of near-shore areas of the

lower Snake River Reservoirs, where dredging is not likely to take place. Samples from proposed dredging sites have not exceeded

screening criteria.

3.9.2.5 Ambient Elutriate

The ambient elutriate analysis is designed to estimate the amount of chemical sorbed to sediment that may desorb into the water

column. As such, it represents the hypothetical water concentration around the sediment particles, with the conservative

assumptions of steady state and undiluted conditions.

In the Corps 1997 sampling (Corps, 1999), the organic chemical ethyl parathion was detected near its detection limit in only one of

98 samples. Because of the low frequency of detection and the relatively low concentration in the one sample in which it was

detected, ethyl parathion is not recommended as a chemical of concern.

However, total DDT is recommended as a chemical of concern. DDT is highly toxic to fish and invertebrates. The primary reason for

this concern is not its toxicity, but rather its bioaccumulation and persistence in the environment. Researchers have demonstrated

the bioaccumulation factor to be between 12,000 and 40,000 times the amounts in the environment (Dustman and Stickel, 1969). J.

B. Diamond et al. (1968) discovered that soil residues applied at 1 pound per acre had very little decrease 9 years after the

application and estimate the DDT residues persist for 30 years or more.

During testing for the Lower Snake River Feasibility Study in 1997, organochlorine pesticide residues were detected in the

sediments of all four lower Snake River reservoirs (Corps, 1999, Appendix C). The predominant compound detected was DDE,

which ranged in average maximum concentration of 6.48 ppb in the Lower Granite reach. Both DDT and DDD were detected with an

average of 1.62 and 2.07 ppb, respectively. None of these compounds were discovered in the elutriate tests taken in 1997. However,

since 1997, EPA has revised the criteria (EPA, 1999). The revised standards are now more restrictive, lowering allowable thresholds

for DDT concentrations in water. The detection limits associated with the testing methods employed in 1997 were not low enough to

determine if DDT was present at the maximum concentration currently recommended by EPA. Consequently, the Corps has not

determined if the 1997 elutriate test results would exceed current EPA criteria recommended for water quality standards for DDT or

its derivatives. The Corps plans to evaluate the issue further to determine what, if any, additional testing and analysis may be

needed.

In June 2000, the Corps sampled for dioxin at 24 designated dredging sites from the confluence of the Snake and Clearwater Rivers

downstream for several miles in Lower Granite reservoir. Chlorinated furans and dioxin congeners have been detected in the past in

these areas (1991, 1996, and 1998). These are products originating from industrial activity in the Lewiston-Clarkston area. Results

showed that there were no concentrations of 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) which is considered a very potent

carcinogen. Less toxic dioxin and furan congeners were found at seven sites at low concentration levels. The Agency for Toxic

Substances and Disease Registry guidelines for evaluating dioxin address TEQ's. A dioxin concentration in soils of 50 parts per

trillion dioxin TEQ's is the screening level for determining public health actions. Of the seven sites with dioxins in the 2000 study, the

highest dioxin concentration was 0.6 part per trillion of TEQ's. In 1997, the Corps sampled four sites from Lower Granite reservoir for

dioxin. Dioxin congeners were detected in two of four sample sites. No 2,3,7,8 TCDD was found.

In the Corps June 2000 study, 20 metals were analyzed in sediments at 33 sites. All metal concentrations were below standards

listed for the compounds in Washington State's Department of Ecology (June 1999). Mercury was below detection levels (less than

0.002 part per million) in all areas. The maximum copper concentration was 44.3 parts per million, which was below copper marine

sediment quality standards (screening limits) of 390 parts per million.

Inorganic substances are ubiquitous in water and can occur at natural background concentrations that are below the most

conservative criteria. Consequently, the inorganic chemicals that exceeded their respective water quality criteria were further

evaluated by comparisons with background levels for the Snake River.

Table 3-19 compares the elutriate results with the background values.

Table 3-19

Elutriate Results With Background Values

Pollutant Elutriate

Average (ppm or mg/l)

Background

Average (ppm or mg/l)

Arsenic 0.0024 0.0047

Copper 0.0135 0.0422

Manganese 0.945 0.050

Mercury 0.00044 0.00053

Source: U.S. Geological Survey

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These comparisons suggest that manganese is the only inorganic chemical in the ambient elutriate analysis that exceeds

concentrations that are upstream of the proposed dredging areas in the lower Snake River.

Sediment ambient elutriate samples were taken from nine sites along the dredging locations of the Lower Granite reservoir and the

Little Goose reservoir. These nine samples were tested for ammonia and nitrate. At these sampling sites, the maximum level of

ammonia was 12.80 ppm (12.80 mg/L) and the average ammonia level was 4.67 ppm (4.67 mg/L). The average nitrate level was

0.31 ppm (0.31 mg/L) and the maximum level measured was 0.47 ppm (0.47 mg/L).

3.9.2.6 Contaminated Sediments

Sediments containing levels of contamination that would require handling as solid or hazardous wastes preclude placement of

dredged sediments either in-water or by proposed upland disposal methods. Dredged sediment with high levels of contamination

require disposal in a solid or hazardous waste landfill.

Sediments identified as hazardous are required to meet the guidance set forth in RCRA. The guidance outlined in the ITM is used to

determine whether dredged sediments are considered hazardous. This guidance is discussed in section 3.9.2.1.

Review of sediment sampling results from the Lower Snake River Feasibility Study indicated five chemicals of concern in ambient

elutriate at contaminant levels that exceed water quality criteria. Based on available data, it is unlikely that those sediments contain

concentrations of constituents that would necessitate their handling as hazardous waste in accordance with RCRA. The Corps’

sediment sampling and analysis, consistent with the dredged material evaluation framework and conducted prior to dredging an

area, would indicate the presence of contaminated sediments that could potentially require special handling.

There could be a possibility of radioactive materials being present in the reservoir sediments within McNary reservoir because of the

location of the Hanford Nuclear Reservation at the upstream end of the reservoir. Any radioactive material within the reservoir would

most likely have been introduced in the 1940's, 1950's, or early 1960's. As the reservoir behind McNary was filled in 1953, any

radioactive material present could have started impacting accumulated sediment at that time. This early introduction into the

reservoir system would most likely results in the radioactive material being located in the lower sediment strata, which would be

unlikely to be affected by any proposed dredging activities.

The U.S. Department of Energy (USDOE) and Washington State Department of Health have evaluated sediments in the Columbia

River for radiological contaminant characteristics. Radionuclide concentrations in Columbia River sediments have been sampled

annually by the USDOE since 1995. Sampling was done at Priest Rapids, McNary, and Ice Harbor dams as well as in the Hanford

Reach. Parameters measured were: cobalt-60; strontium-90; cesium-137; and plutonium-239/240. Radionuclide concentrations in

Columbia River sediments were relatively constant for 1995 through 2000 (DOE 2001). Washington State Department of Health

evaluated potential radiation doses and attendant risks for the maximum concentrations of radionuclides observed in the Columbia

River. Their report concluded:

"The maximum radiation doses to the maximally exposed individuals comes from the deeply buried sediments of McNary

Dam. The maximum annual average dose over a 75 year lifetime is 1.6 (millirem) mrem. This dose requires that the deep

sediments be dredged to the surface...In all cases the calculated doses are low and less than 1% of natural

background. In fact, the risks from these doses are less than the risks associated with existing federal standards for

radionuclides in drinking water and air emissions (Wells, 1994)."

No specific federal or state freshwater sediment criteria are available to assess the sediment quality of the Columbia River with

respect to radiological parameters (DOE 2001).

3.9.3 Wetlands

Wetlands were identified using spatial data provided through the NWI, field reconnaissance, aerial photo interpretation, and

information provided in previous studies. Previous studies were used to provide a general description of wetland types and

approximate acreage throughout the geographic study area. The NWI data (gathered between 1983 and 1990) was compiled from

aerial photo interpretation and is not necessarily inclusive of all wetlands within a given area. Field reconnaissance was performed

to field verify NWI data and assess additional wetlands on the sites proposed for up land disposal of dredged material. Site visits

were also conducted in the areas potentially affected by the proposed nominal 3-foot (0.9- m) levee raise and associated roadway

modifications. Field approximations of size and type of wetlands were based on indicative characteristics such as vegetation and

water.

There are approximately 1,010 acres (408.7 hectares) of emergent wetlands located in and along McNary reservoir. The wetlands

are predominately located at the confluence of the Walla Walla and Snake Rivers and the Yakima and Columbia Rivers (Corps,

1992). The lower Snake River reservoirs are also characterized by emergent wetland vegetation at the edge of the water surface and

in backwater areas. Wetland acreage in these reservoirs is estimated as: Lower Granite [18 acres (7.3 hectares)], Little Goose [84

acres (34.0 hectares)], Lower Monumental [65 acres (26.3 hectares)], and Ice Harbor [186 acres (75.3 hectares)] (Corps, 1999).

These wetland locations and structure are typically influenced by reservoir elevation, which is not anticipated to change under any

of the alternative scenarios considered in this DMMP/EIS.

For the Joso site, NWI mapping indicates that there is approximately 0.2 acre (0.08 hectare) of palustrine shrub wetlands located on

a northeast inlet area. This wetland was verified by field reconnaissance. Plant composition of this wetland includes Russian olive

(Elaeagnus angustifolia), false indigo (Amorpha fruticosa), cattail (typha spp.), wild onion (Allium douglasii), and teasel (Dipsacacea

spp).

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Two other wetlands, not indicated on NWI, were also identified on the Joso site. These are located along the southwest edge of the

parcel in two shallow inlets. Both wetlands have vegetative characteristics indicative of palustrine submerged and emergent

wetlands. The first wetland is approximately 0.1 acre (0.04 hectare), and the second wetland to the north is estimated at 0.8 acre

(0.32 hectare). Some of the rushes and sedges also showed signs of foraging animals and a pair of great blue heron were observed

at the northern wetland during the field visit. Vegetation at these two locations is diverse and native plants dominated the sites. The

dominating plant material observed included pondweed (Potamogeton spp.), hornwort (Ceratophyllum spp.), tule (Scirpus

tabernaemontani), dock (Rumex crispus and salicifolius), American brooklime (Veronica anagallis-aquatica), false loosestrife

(Ludwigia palustris), cattails (Typha spp.), Harding grass (Phalaris spp.), and rushes (Juncus spp.).

Wetlands may be present at other sites that may be considered for beneficial uses of dredged material. The Corps would survey

potential beneficial use sites to assess wetland resources.

3.9.4 Floodplain Areas

The 100-year floodplain designation is commonly used to represent area where there is a 1 percent probability of inundation by

flooding once each year. Restrictions are often placed on activities within a floodplain. The Corps policy for any development is that

fill placed within the 100-year floodplain must be balanced by removing fill so that the net impact to flood storage is zero.

The 100-year floodplain for the study area reservoirs would vary depending on surrounding topography and hydrologic conditions.

The existing levees in the Lewiston area are designed to guard against the SPF, which is greater in discharge than the 100- year

flood event. Although sedimentation has reduced the flow conveyance in the vicinity of the confluence of the Clearwater and Snake

Rivers, the levees do provide protection from a 100-year flood event beyond the year 2020.

The proposed levee raises are designed to provide enhanced flow conveyance. The proposed upland disposal location at Joso was

evaluated to determine if any proposed dredged material placement is within the floodplain. Portions of the Joso site are within the

100-year floodplain. However, the proposed disposal area is not located within the floodplain area. Proposed temporary storage

areas for dredged material at the site are partially within the 100-year floodplain. The proposed woody riparian habitat creation site

at Chief Timothy HMU is within the 100-year floodplain. Specific floodplain areas that may be associated with other potential

beneficial uses of dredged material were not evaluated. However, the process of determining beneficial uses and disposal areas

would identify and evaluate floodplain areas early in the process.

3.10 HAZARDOUS, TOXIC, AND RADIOACTIVE WASTE (HTRW)

3.10.1 Dredged Material

Sediments proposed for dredging have been tested for HTRW. The latest sediment sampling and analysis for hazardous materials,

substances, chemicals, and wastes was completed in September 1998. Reviews of sediment sampling results indicate it is unlikely

that sediments contain concentrations of constituents that would necessitate their handling as HTRW in accordance with RCRA.

Additional information on contaminants in the sediments is discussed in section 3.9.2.6.

3.10.2 Upland Disposal Site

The potential or actual presence of HTRW within the study area can influence whether and how the proposed action would be

implemented. To assess the presence of HTRW in and around the proposed upland disposal site (Joso), a Phase 1 Environmental

Site Assessment was conducted in accordance with the requirements of the ASTM Standard Practice for Environmental Site

Assessments: Phase 1 Environmental Assessment Process E 1527. This site assessment included a title search; reviews of Federal,

state, and local environmental records and databases (such as the Superfund National Priority List of sites, underground storage

tank site lists, and spill reports); review of historical records; site reconnaissance; and interviews with landowners, lessees/tenants,

and local agency officials.

The Joso site is owned by the Corps and is managed as an HMU. The site has historically been used for rock and gravel mining

operations. Large portions of the site were excavated and the pits have been left open. Review of environmental and historical

records indicated no HTRW concerns requiring further investigation at the site (HDR, 1999a). Site reconnaissance revealed the

presence of an area where past tire burning and asphalt dumping has occurred. Remnants of these activities that remain at the site

are rusted belts from the tires (approximately 30 tires) and weathered asphalt (HDR, 1999b).

3.11 AIR QUALITY

The DMMP/EIS study area encompasses the Snake and Columbia Rivers and includes Lewiston County in Idaho; Walla Walla,

Franklin, Columbia, Whitman, Garfield, and Asotin Counties in Washington; and Umatilla County in Oregon. This section discusses

general air quality conditions and regulating agencies throughout the study area. As discussed in section 2, the Corps would

continue maintenance activities in Lake Wallula behind McNary on the Columbia River and the reservoirs behind Ice Harbor, Lower

Monumental, Little Goose, and Lower Granite on the lower Snake River. Lower Granite is the most upstream of the four lower Snake

River dams and provides navigation to Lewiston, Idaho, and Clarkston, Washington. Because the majority of proposed dredging and

construction activities would occur in the Lewiston-Clarkston area and the Lower Granite reservoir, this section will focus on that

area.

3.11.1 Meteorology

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Within the study area of Northeastern Oregon, Southeastern Washington, and Northwestern Idaho, the climate is typically arid with

relatively minimal cloud cover, and elevations range from approximately 300 to 750 feet above sea level. Looking at several cities

within the study area from Oregon to Idaho, average annual rainfall ranges from 7 to 13 inches (17.8 to 33.0 cm). Average

temperatures range from 35 to 37 "F (1.7 to 2.8 "C) in the winter, and 71 to 74 "F (21.7 to 23.3 "C) in the summer (Western Regional

Climate Center, 2000). The prevailing wind direction in the study area is southwesterly. Storm activity in the summer and fall leads

to strong wind gusts making the arid study area prone to wind erosion and dust storms.

3.11.2 Fugitive Dust Emissions

Activities associated with DMMP/EIS implementation have the potential to generate windblown particulate matter (PM) (fugitive

dust), particularly during levee construction, material transport, and in-water and upland disposal. Health concerns associated with

suspended particles focus on those particles small enough to reach the lungs when inhaled. Children, the elderly, and those with

respiratory diseases can be affected most. Few particles larger than 10 microns in diameter reach the lungs (a micron is equal to

one-millionth of a meter.) In 1997, EPA added two new PM2.5 standards, set at 15 micrograms per cubic meter (μg/m 3 ) and 65

μg/m3, respectively, for the annual and 24-hour standards. In addition, the form of the 24-hour standard for PM10 (about one-seventh

the diameter of a human hair) was changed. These standards have been challenged in court and the case is pending before the

U.S. Supreme Court. The EPA is beginning to collect data on PM2.5 concentrations. Beginning in 2002, based on 3 years of

monitoring data, EPA could designate areas that do not meet the new PM2.5 standards as non-attainment areas.

Fugitive (i.e., uncontrolled) dust releases are generally the largest source of PM10 emissions during construction activities.

Emissions depend on wind conditions, soil type, soil moisture content, and total area of soil disturbance. Dust emissions could be

generated by wind blowing over exposed soil surfaces during levee construction, grading and scraping activities, and the spreading

and compacting of soil at the upland disposal areas. Both upland and in-water disposal could also be a source of dust as dredged

material dries and is transported and distributed. The movement of construction equipment and support vehicles around the

proposed project sites could also generate dust. However, impacts of fugitive dusts can be greatly abated using standard

construction practices such as wetting exposed soil, watering haul roads, and placement of soil amendments to fix fine particles.

3.11.3 Equipment Exhaust Emissions

Heavy equipment used for dredging, material transport, and disposal would include cranes, tug boats (e.g., for pulling/pushing

barges), tractors, and heavy trucks. These are generally powered by diesel engines that emit low quantities of hydrocarbon and

carbon monoxide emissions. Diesel engines do produce larger quantities of particulates and nitrogen oxides than gasoline engines.

Use of diesel-powered equipment is a common component of existing and proposed dredging/maintenance activities and equipment

use is not specifically regulated (Ecology, 1999). Thus, this discussion focuses primarily on fugitive dust emissions. It is reasonable

to expect transportation-related emissions will continue to decline as fuel efficiencies improve and national emission standards

become effective.

3.11.4 National Ambient Air Quality Standards (NAAQS)

The states of Washington, Oregon, and Idaho have adopted the NAAQS listed in table 3-20. The NAAQS include primary standards,

designed to protect public health, and secondary standards, designed to protect public welfare from effects such as air pollution

damage to property and vegetation.

Pursuant to the Clean Air Act, the EPA has developed regional or local classifications for each Federal criteria pollutant. An area is

classified as in "attainment" if pollutant concentrations meet the NAAQS. Areas where concentrations exceed the NAAQS for that

pollutant are designated as "non-attainment." Areas that have not received sufficient analysis for certain criteria pollutants are

designated as "unclassified" for those particular pollutants.

Table 3-20

National Ambient Air Quality Standards

Pollutant Averaging Time

National

Standards

Sulfur Dioxide (SO2)

Annual Arithmetic Mean 0.03 ppm

24-Hour Primary* 0.14 ppm

3-Hour Secondary* 0.50 ppm

Particulate matter(PM10)

Annual Arithmetic Mean:

Primary and Secondary 50 μg/m3

24-Hour:**

Primary and Secondary 150 μg/m3

Particulate matter(PM2.5)

Annual Arithmetic Mean:

Primary and Secondary 15 μg/m3

24-Hour:**

Primary and Secondary 65 μg/m3

Carbon Monoxide (CO) One Hour* 35 ppm

8 Hour* 9 ppm

Ozone (O3) One Hour*** 0.12 ppm

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8 Hour*** 0.08 ppm

Nitrogen Dioxide (NO2) Annual Arithmetic Mean 0.053 ppm

Lead (Pb) 3-Month Arithmetic Mean 1.5 μg/m3

* Not to be exceeded more than once per year.

** Statistically estimated number of days with exceedances, not to be more than one per year.

*** Not more than one expected exceedance per year on a 3-year average

ppm Parts of pollutant per million parts of air [by volume at 77 °F (25 °C)]

μg/m3 Micrograms of pollutant per cubic meter of air

Source: U.S. Environmental Protection Agency

3.11.5 Washington Air Quality Standards

The study area in Washington State includes Benton, Walla Walla, Franklin, Columbia, Whitman, Garfield, and Asotin Counties. Air

quality in all these counties except Benton County is regulated by the Washington Department of Ecology (Ecology) Eastern

Regional Office located in Spokane. Benton County is regulated by Ecology’s Benton County Clean Air Authority located in

Richland. The Washington study area is primarily designated unclassifiable for criteria pollutants. The City of Wallula in Walla Walla

County is designated as a PM10 non-attainment area. The EPA’s Natural Events Policy, adopted in 1996, excludes exceedences due

to dust storms from evaluating attainment status for an area. In 1998, Ecology developed controls for the area for any human

activities, including construction, that contribute to exceedences. These controls include the following:

Use phased development to keep the disturbed area to a minimum.

Schedule thorough and consistent watering that does not run off the site.

Use wind fencing.

Restrict traffic on the site.

Reduce vehicle speed.

Cover any trucks transporting dirt.

Plan schedules so control measures are available throughout the project.

The City of Kennewick, Washington, has also been of concern to the Benton Clean Air Authority for similar windblown dust issues.

The Benton Clean Air Authority adopted an Urban Fugitive Dust Policy in 1996 that outlines requirements (appendix B of the Policy),

similar to ones above, for construction activities and hauling material.

Activities associated with dredging, transport, and disposal would be designed to comply with regulations defined in Washington

Administrative Code (WAC) 173-400-040 general standards for maximum emissions, subsections 1 - Visible emissions, 2 - Fallout, 3

- Fugitive emissions, 5 - Emissions detrimental to persons or property, and 8 - Fugitive dust sources. Localized diesel emissions

may increase during dredging, transport, and disposal, but should have little impact on ambient air quality. Emissions from these

activities proposed in this DMMP/EIS are currently not regulated by Ecology (1999), and there are no plans to regulate such

emissions in the future.

3.11.6 Idaho Air Quality Standards

Air quality in Nez Perce County and the City of Lewiston is managed by the Idaho DEQ, Lewiston Regional Office. Lewiston is also

part of the Eastern Washington-Northern Idaho Air Quality Control Region. Because the Lewis Clark Valley airshed crosses city,

county, and state boundaries, the Lewis Clark Valley Air Quality Advisory Commission was formed in 1989 to address carbon

monoxide and PM10 issues. The commission includes authorities from Washington and Idaho, as well as Asotin County and the

cities of Asotin, Lewiston, and Clarkston.

Rules for Control of Air Pollution in Idaho are given in IDAPA, DEQ, 58.01.01. Fugitive dust control requirements for the State of

Idaho are given in IDAPA 58.01.01, Sections 650 and 651, and require that all reasonable precautions be taken to prevent the

generation of airborne particulate matter (fugitive dust). Reasonable precautions would include, but are not limited to, the following:

Use of water or chemicals during construction or demolition activities.

Application of dust suppressants (water, oil, suitable chemicals) where practical.

Covering of trucks when practical when transporting material likely to emit dust.

Localized diesel emissions may increase during dredging, transport, and disposal. Emissions from the activities proposed in this

DMMP/EIS are currently not regulated by the Idaho DEQ and there are no plans by the state to regulate such emissions in the

future.

3.11.7 Oregon Air Quality Standards

The study area in eastern Oregon is located within Umatilla County and is managed by the Oregon DEQ Eastern Region. The

nearest Eastern Region office is located in Hermiston. Air quality requirements are defined in the Oregon Statute Title 36, Chapter

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468A and do not specifically address fugitive dust control, but similar diesel and fugitive dust control measures as outlined above

would be followed throughout the study area. General air pollution control requirements most likely applicable to the study area are

given in Chapter 468A, Sections 468A.005 - 468A.085.

Localized diesel emissions may increase during dredging, transport, and disposal. Emissions from the activities proposed in this

DMMP/EIS are currently not regulated by ODEQ and there are no plans by the state to regulate such emissions in the future.

3.12 NOISE

The DMMP/EIS study area encompasses the Snake and Columbia Rivers and includes Nez Perce County in Idaho; Walla Walla,

Franklin, Benton, Columbia, Whitman, Garfield, and Asotin Counties in Washington; and Umatilla County in Oregon. This document

focuses on general noise conditions throughout the study area and specifically addresses Lewiston, Idaho, and Clarkston,

Washington. As discussed in section 2 of this document, the Corps would continue maintenance activities in Lake Wallula behind

McNary on the Columbia River and the reservoirs behind Ice Harbor, Lower Monumental, Little Goose, and Lower Granite on the

lower Snake River. Because the majority of proposed dredging and construction activities would occur in the Lewiston-Clarkston

area and the Lower Granite reservoir, this section will focus on that area.

For the purpose of analysis, it is assumed dredging activities near Lewiston and Clarkston would occur 24 hours per day from

December 15 through March 1. Transport and disposal near populated areas would occur during daytime hours (i.e., 7 a.m. to 10

p.m.).

3.12.1 Background Information on Noise

Sound travels through the air as waves of minute air pressure fluctuations caused by some type of vibration. In general, sound

waves travel away from the noise source as an expanding spherical surface. As a result, the energy contained in a sound wave is

spread over an increasing area as it travels away from the source. This results in a decrease in loudness at greater distances from

the noise source. The human ear does not respond equally to all sound frequencies. Therefore, when considering the effects of

noise on people, it is necessary to consider the frequency response of the human ear. The frequency weighting most often used to

evaluate environmental noise is A-weighting, which reduces the measured sound pressure level for low- frequency sounds while

slightly increasing the measured pressure level for some high- frequency sounds. Noise levels referenced in this evaluation are

reported in "A-weighted decibels" or dBA.

3.12.2 Existing Noise Levels

The study area in Washington, Idaho, and Oregon is primarily rural with relatively few noise sources. Sources include isolated

industrial facilities, train and boat operation, and distant highway noise. Because the area is rural and sparsely populated,

background noise levels at locations distant from traveled roadways are likely to be between 30 and 40 dBA under calm wind

conditions. Noise levels within the cities of Lewiston and Clarkston are typical of those found in urbanized areas and vary by location

and time of day. Table 3-21 shows typical noise sources and associated noise levels. Noise levels in proximity to roadways range

from 60 to 70 dBA along arterials and freeways and are affected primarily by traffic volumes and speed. Residential noise levels are

likely near 50 dBA and maybe quieter during evening and nighttime hours.

Table 3-21

Weighted Sound Levels and Human Response

Sound Source dBA* Response Criteria

Carrier deck jet operation 140 Limited amplified speech

130 Painfully loud

Jet takeoff (200 feet) 120 Threshold of feeling and pain

Discotheque Maximum vocal effort

Auto horn (3 feet)

Riveting machine 110

Jet takeoff (200 feet)

Shout (0.5 feet) 100 Very annoying

New York subway station

Heavy truck (50 feet) 90 Hearing damage (8 hours)

Pneumatic drill (50 feet)

Passenger train (100 feet) 80 Annoying

Helicopter (in-flight, 500 feet)

Freight train (50 feet)

Freeway traffic (50 feet) 70 Telephone use difficult

Intrusive

Air conditioning unit (20 feet) 60

Light auto traffic (50 feet)

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50 Quiet

Living room

Bedroom 40

Library

Soft whisper (15 feet) 30 Very quiet

Broadcasting studio 20

10 Just audible

0 Threshold of hearing

*Typical A-weighted sound levels taken with a sound-level meter and expressed as decibels on the scale. The "A" scale approximates the

frequency response of the human ear.

Source: U.S. Council on Environmental Quality, 1970.

3.12.3 Washington Noise Control Standards

Chapter 173-60 WAC specifies noise limits that restrict both the level and duration of noise measured at any given point within a

receiving property. The maximum permissible environmental noise levels depend on the Environmental Designation for Noise

Abatement (EDNA) of the property containing the noise source and the land use of the property receiving that noise. For the

purpose of this evaluation, dredged material disposal is considered either maintenance of an essential utility service or a temporary

construction activity. Thus, noise would be exempt from regulation between 7 a.m. and 10 p.m. per WAC 173-60-050(1)(e) and

(3)(a). Noise from watercraft (i.e., tugboats and barges) generated during material transport would be exempt from regulation per

WAC 173-60-050(4)(j) at all times.

Noise within Asotin County, Washington, is regulated by Ordinance 97-30. Ordinance 97-30 is designed primarily to control

nuisance noises and does not pertain directly to dredging or related activities proposed as part of the DMMP/EIS. County staff

indicated that dredging activities similar in scope to that proposed under the DMMP/EIS have occurred in the Clarkstonarea in the

past. Dredging activities were not in violation of Ordinance 97-30. County staff indicated that a letter to the county commissioners

providing notice of future dredging activities would be adequate to ensure continued compliance with Ordinance 97-30 (Riggers,

1999). Asotin County noise ordinances and/or control measures would be applicable to proposed dredging and construction

activities in the vicinity of Clarkston.

3.12.4 Idaho Noise Control Standards

The portion of the study area in Idaho is located in and around the City of Lewiston. Noise within the City of Lewiston is regulated

under Article II. Noise Control and Regulation, Sections 24-37 through 24-43 of the Lewiston Code. Dredging and transport of

dredged material would be considered a repair and/or maintenance of an essential utility; thus, activities would be exempt from

regulation. A sound level variance permit would not be required (Ayers 1999).

Sounds associated with levee construction would be temporary and would occur during daytime hours. Typical construction noise

would also be exempt from regulation.

3.12.5 Oregon Noise Control Standards

A small portion of the study area is located in Umatilla County, Oregon. The Oregon DEQ coordinates a state-wide program of noise

control and state-wide noise control regulations are listed under the Oregon Administrative Rules, Division 35 Noise Control

Regulations. Project activities within Umatilla County would require the notification of County officials and compliance to local noise

ordinances. Typical temporary construction noise is usually exempt during weekday daytime hours.

3.13 AESTHETICS

3.13.1 Visual Resources

The lower Snake River system and the Columbia River upstream of McNary are located in an arid region with surrounding open and

agricultural landscapes interspersed with urban, suburban, and industrial land uses. The study area is predominantly rural in

character. The river passes through and is adjacent to the Blue Mountains and Columbia Basalt Plain physiographic provinces. As

the Snake River approaches the Tri-Cities area, the land surrounding the river is comprised of low hills with steppe vegetation.

Moving upstream, the valley walls become steeper, forming a canyon with sidewalls ranging from 200 to 2,000 feet (61.0 to 609.6 m)

high. The steep buttes and walls surrounding the river are the dominant features of this landscape (figure 3-4). Throughout much of

the study area, roadways (e.g., U.S. Highway 12) and railroad facilities are adjacent to the reservoirs. Levees have been constructed

in several areas, notably in Lewiston-Clarkston and the Tri-Cities areas.

Figure 3-4. Aesthetics of the Study Area

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Mouth of Alpowa Creek, Downstream of Chief Timothy State Park, Lower Granite Reservoir

Shoreline of Lower Monumental Reservoir at the Joso Site

The river provides a water feature in an arid landscape with often dramatic, steep surrounding hillsides and canyons, making it an

important aesthetic resource in the study area. Many of the recreational facilities that have been developed along the lower Snake

River (see section 3.4) take advantage of the scenic qualities of this landscape, as well as water-based recreation such as boating and

fishing. In the urbanized areas of the Tri-Cities and Lewiston-Clarkston, extensive riverfront parkland has been developed and is

heavily used.

The proposed upland dredged material disposal site at Joso is an open terrace area with limited development in areas surrounding

it (see figure 3-4). An abandoned quarry area is located near the center of the site, and roadway and railroad facilities are located

adjacent to the site.

3.13.2 Viewers and Viewing Patterns

People viewing the aesthetic resources of the project area include highway travelers, recreational users of the river and surrounding

lands, and local residents. The aesthetic values of the river and surrounding landscapes vary based on the viewers’ perspectives

and values. Highway travelers tend to view the resources as they are traveling on roadways through the study area, such as along

U.S. Highway 12, which parallels the Snake River over several stretches of its alignment; as such, these travelers tend to view the

resources at a distance, generally from an automobile and generally at high rates of speed. Recreational users, such as boaters,

campers, swimmers, and fishermen, tend to view the resources for longer periods of time due to the fact that they are involved in

recreational activities that are dependent on the river setting. Local residents tend to view the resources as they go about their daily

business in the vicinity of the river as well as when they use the river and surrounding lands for recreational purposes (Corps, 1992).

Existing levees vary in height and run for approximately 8.6 miles (13.8 km) along the shorelines of the Snake and Clearwater

Rivers. The levees in Lewiston and Clarkston provide a visual as well as recreational resource, with landscaping, walking paths, and

points that provide views of the river (from the top of the levee). The levees do obscure views of the river from various locations in

Lewiston.

Throughout the study area, viewing patterns would vary seasonally in a manner similar to recreational uses of the river and

surrounding lands, with more activities during the warm and sunny periods in late spring, summer, and early fall.

3.14 NATIVE AMERICAN TRIBES AND COMMUNITIES

3.14.1 Summary

The United States has long recognized the dependent sovereign status of Indian tribes. Principles outlined in the United States

Constitution and treaties, as well as those established by Federal laws, regulations, and executive orders, continue to guide the

nation’s policy toward Indian nations.

The Corps conducts its government-to-government relationships with Federally recognized Indian tribes as a part of its obligations,

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just as it does with states, counties, and local governments. The relationship the Federal government maintains with tribes is unique

and necessarily involves consultation with tribal governments. The Corps is responsible for assessing the impacts of agency

activities, considering tribal interests, and assuring that tribal interests are considered in conjunction with Federal activities and

undertakings.

The Corps recognizes that tribal governments are sovereigns located within and dependent upon the United States. Yet tribes have

rights to set their own priorities, to develop and manage tribal resources, and to be consulted in Federal decisions and activities

having the potential to affect tribal rights. The Corps has a responsibility to help fulfill the United States government’s

responsibilities toward tribes when considering actions that may affect tribal rights, resources, and assets. The Corps is committed

to carrying out Federal activities in a manner that is consistent with the United States’ legal obligations toward tribes.

3.14.2 Introduction

The Federal government has a unique relationship with American Indian peoples and Federally recognized tribal governments.

Principles outlined in the United States Constitution and treaties, historic executive orders, and mandates established in Federal

laws, regulations, and modern executive orders, continue to guide our national policy towards American Indian nations.

Prior to the formation of Federally recognized tribes, the indigenous peoples of the McNary and lower Snake River region lived in

villages comprised of several extended families. Groups of villages known as bands were bound together culturally and collectively

shared a homeland. The names of bands were typically taken from those of major villages. Through formal treaties and executive

orders initiated by the United States government, groups of native bands were given Federal recognition as American Indian tribes.

In the mid-1800's, the tribes ceded their homelands to the United States through treaties ratified by Congress. As domestic

dependent nations, Indian tribes exercise inherent sovereign powers over their members and territory. American Indian tribes are

defined as "any Indian band, nation, village or community" the Secretary of the Interior acknowledges to exist as an Indian tribe

pursuant to the Federally Recognized Indian Tribe List Act of 1994, 25 U.S.C. 479a. Thus, the word tribe denotes Federal

recognition of an American Indian government.

The modern tribes with cultural heritage pertaining to McNary and the lower Snake River are comprised of numerous communities

associated with the Umatilla, Yakama, Nez Perce, and Colville reservations, and families associated with the Wanapum community

at Priest Rapids, Washington. Tribal members are both Americans and tribal citizens who may receive representation from Federal,

state, county, and local governments. The unique manner in which tribal governments represent their members is perhaps the most

sensitive to their immediate economic and cultural needs and values. The potential effects of the DMMP may directly relate to tribal

economies and cultural practices and indirectly to people’s health, social well-being, quality of life, and values for the natural and

cultural environment associated with the lower Snake and Mid-Columbia Rivers.

Affected tribes and American Indian communities maintain cultural values in both natural and cultural resources managed by the

Corps in McNary and the lower Snake River. Numerous aquatic, plant, and wildlife species retain cultural significance to tribes (e.g.,

salmonids, Pacific lamprey, sturgeon, whitefish, sculpin, deer, grouse, eagles, coyotes, bear, wolves, biscuitroot, Indian carrots,

chokecherries, and tules). Values for the water, land, life forms, and places continue to be the source of Indian community

concerns, as well as tribal governments’ desires to protect their legal rights. Such values are lodged in both traditional lifeways and

modern socioeconomic needs, which influence and impact tribes.

Changes to tribes’ cultural identities and limitations imposed on traditional practices are ongoing. For example, the fisheries on and

adjoining McNary and the lower Snake River system have been significantly altered over the past one and a half centuries in terms

of access and habitat quality. Tribes that desire to take treaty fish such as Pacific lamprey (largely a ceremonial and subsistence

activity) find their fishermen displaced from local fishing stations. Tribes such as the Yakama, Nez Perce, and Umatilla currently

catch lamprey from tributaries of the lower Columbia River.

Federally recognized tribes have the right to set their own priorities and develop and manage tribal resources within the Federal

government framework. Tribal interests and rights are viewed by tribes and traditional communities with the spatial context of tribal

ceded lands, traditional native homelands, and places traditionally used by native peoples. Places where tribes have rights to

harvest resources may include fishing grounds and stations, root and berry fields, and hunting grounds. Of particular concern to

tribes are the potential impacts from water resource management on anadromous fish runs and associated aquatic habitats, and

tribal rights to fish for ceremonial, subsistence, and commercial needs.

Additional Information, incorporated by reference, on Native Americans can be found in the Feasibility Study and Appendix Q, Tribal

Coordination and Consultation. In assessing effects of the DMMP’s proposed courses of action on tribes, the following factors may

be considered: 1) water quality and aquatic habitats; 2) accessibility to culturally and religiously significant places and resources; 3)

viability and harvestability of culturally significant species; and 4) quality of habitat places that would impact treaty rights to hunt,

fish, gather, and graze livestock. Short- and long-term effects on these factors are expected to differ.

3.14.3 Issues and Concerns

Potential effects of the DMMP could result in impacts to tribal communities within the study area. Given that the DMMP is largely

associated with in-water activities in the McNary and four lower Snake River reservoirs, tribes are concerned with affects to their

treaty rights and interests associated with the study areas’ aquatic ecosystem. [See the Aquatic Resources and Biological

Assessment appendices (F, G, and K) for a detailed description of the study area’s aquatic ecosystem. These appendices also

provide information on the condition of species and population trends.]

Specifically, tribes are interested in the health and function of this ecosystem since significant changes could impact the numbers

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and condition of resources the tribes seek to harvest (e.g., chinook and coho salmon, steelhe ad, pacific lamprey, bull trout, and

white sturgeon). The presence and condition of aquatic species in the lower Snake and Mid-Columbia Rivers are considered, by

tribes, to be a direct indicator of the health of fisheries available to them for the meaningful exercise of their tribal fishing rights. To

ascertain the condition of these fisheries, tribes examine the conditions and changes to water quality, anadromous fish habitat,

fishing places and their access, and competing/predatory fish species populations that may affect tribes’ fisheries.

Tribes express concerns if Federal actions have the potential to alter or diminish habitat conditions that aquatic species rely on to

migrate, spawn, and feed. Improved or diminished tribal fisheries have the potential to impact social-economic conditions in some

tribal communities (Meyer Resources, 1999). Tribes are also concerned about effects to water quality as a health issue. The ability

of tribes to maintain their cultural traditional knowledge and practices has the potential to be directly and negatively affected by

changes in the aquatic ecosystem.

Another important issue for tribes is the potential impact of DMMP activities on cultural resources (i.e., archaeological sites and

traditional cultural properties). Almost 600 cultural sites/properties documenting over 11,000 years of human occupation are located

within the project area. Tribes and traditional Indian communities have a lengthy history within the study area and have developed

complex "place attachments" that have become an integral part of community lifeways and values. This is still evident in

communities today even as they adapt and change with modern times. Preservation of traditional cultural places and resources of

significance to traditio nal communities is a concern of the tribes and is considered by Federal agencies during the planning of

Federal undertakings.

Tribes have concerns for cultural properties that lie beneath reservoir waters. Management of these properties using standard me

thods and procedures is difficult under such conditions. The District is presently undertaking a multi- year study to identify

traditional cultural properties located within the McNary and four lower Snake River reservoirs. As these properties are formally

documented, they will be considered in planning DMMP actions. Additional cemeteries, villages, homesteads, food processing

stations, and ceremonial places could all lie unknown and undocumented beneath reservoirs. Tribes are concerned that such

properties and cultural values associated with them may be affected under the DMMP. At least one tribe has indicated that burial of

cemeteries under dredged materials is inappropriate given their religious values.

Tribes would like their interests and rights considered within the context of certain tribal cultural values and perspectives not

universally represented in Federal decision- making. The context for tribal interest must be examined both from the perspective of

Federal legal responsibilities as well as those points raised by tribal government representatives. Protection of treaty rights and

resources and cultural resources are of interest to both tribes and the Corps.

3.14.4 Government-to-Government Relations

National policy statements originating from the executive branch of the Federal government provide direction to Federal agencies on

how to formulate relations with American Indian tribes and people and deal with common issues. The following are those most often

referred to by Federal and tribal representatives:

1983 - Presidential Statement on American Indian Policy (19 Weekly Comp. Doc. 98-102). President Reagan’s statement dated

January 24, 1983, provided direction on treatment of American Indian tribes and their interests.

1984 - Department of Defense Directive No. 4710.1- June 21.

1993 - Executive Order 12866, Regulatory Planning and Review. The Order enhanced planning and coordination concerning new

and existing regulations. It made the regulatory process more accessible and open to the public. Agencies were directed to seek

views of tribal officials before imposing regulatory requirements that might affect them.

1994 - Executive Order on Environmental Justice.

1994 - White House Memorandum for the Heads of Executive Departments and Agencies. This emphasized the importance of

government-to-government relations with tribal governments and the need to consult with tribes prior to taking actions that may

affect tribal interests, rights, or trust resources.

1994 - Government -to-Government Relations with Native American Tribal Governments, Memorandum of 22 April 1994.

1995 - Government -to-Government Relations. The United States Justice Department, Attorney General, issued and signed a policy

statement on government-to-government relations on June 1, 1995. It includes references to tribes’ sovereignty status and the

Federal government’s trust responsibility to tribal governments.

1998 - Executive Order 13084, Consultation and Coordination with Indian Tribal Governments, May 14, 1998.

Policy Guidance Letter No. 57, Indian Sovereignty and Government Relations with Indian Tribes. Implements Executive Order 13084.

1998 - DOD American Indian and Alaskan Native Policy, 20 October 1998.

1999 - Project Operations Native American Policy, 12 July 1999.

As noted in Executive Order 13084, the Federal government continues to work with tribes on issues concerning tribal selfgovernment, trust resources, tribal treaty, and other rights as one government to another government. The Order directs agencies to

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consider affected Federally recognized tribes through the following policy principles:

The United States has a unique legal relationship with Indian Tribal governments as set forth in the Constitution, treaties,

statutes, executive orders, and court decisions.

1.

Tribes, as dependent nations, have inherent sovereign powers over their members and territories with rights to selfgovernment. The United States works with tribes as one government to another government addressing issues concerning

tribal self-government, trust resources, and tribes’ treaty and other rights.

2.

Agencies will provide regular, meaningful, and collaborative opportunities to address the development of regulatory practices

that may have significant or unique effects on tribal communities.

3.

Cooperation in developing regulations on issues relating to tribal self- government, trust resources, or treaty and other rights

should use, where appropriate, consensus-building methods such as rule-making.

4.

The historic development of Federal relations with tribes is based also on many important legal concepts and congressional actions

that now form the basis of modern government-to-government relations.

See section 6.4 of this document for further discussion of the Corps’ tribal consultation efforts.

Section 4

Environmental Effects of Alternatives

This section presents the anticipated environmental effects of the plan alternatives discussed in section 2.5. Consistent with the

Council on Environmental Quality’s regulations implementing NEPA, environmental effects can be described as:

Direct effects, which are caused by an action and occur at the same time and place;

Indirect effects, which are caused by an action, but are later in time or removed in distance from the action (40 CFR 1508.8);

and

Cumulative effects resulting from the incremental impact of an action when considered in combination with past, present, and

reasonably foreseeable future actions, regardless of the agency or individual that undertakes such other actions.

Cumulative impacts can result from actions that are, of themselves, minor, but when considered collectively over time, can be

significant (40 CFR 1508.7). Cumulative impacts are discussed in section 4.14.

Evaluations of environmental effects presented in this section were based on:

Documentation of past activities similar to those considered in this EIS.

Data available on current environmental conditions and probable environmental effects.

Scientific analysis, knowledge, and experience.

Given the programmatic nature of this DMMP/EIS, efforts were made to project environmental effects of a long-term program. Of

necessity, some evaluations of environmental effects are qualitative in nature. Evaluations of the duration and potential severity of

anticipated impacts are presented. In general, impacts are characterized as beneficial (positive) or adverse (negative). The severity

of impacts is described as minor, moderate, or major, and the duration of the impacts are generally described as short- or long-term.

In some instances where impacts are expected to have a temporary duration, but would be recurring regularly over the 20-year

timeframe of the DMMP/EIS, the effects are described as short-term. Where adverse environmental effects are expected, mitigation

measures have been proposed.

Table 4-1 presents a summary of the anticipated environmental effects of the plan alternatives considered in this DMMP/EIS.

Table 4-1

Environmental Effects Summary Matrix

Discipline

Alternative 1

No Action (No Change) -

Maintenance Dredging,

In-Water Disposal

Alternative 2

Maintenance Dredging,

Beneficial In-Water

Disposal,

3-Foot Levee Raise

Alternative 3

Maintenance Dredging,

Upland Disposal,

3-Foot Levee Raise

Alternative 4

Maintenance Dredging,

RDT Recommended

Beneficial Use

Of Dredged Material,

3-Foot Levee Raise

Aquatic Resources

Indirect, minor, short-term

effects on food source for

aquatic species. Potential

beneficial effects from

Indirect, minor, short-term

effect on food source for

aquatic species. Potential

beneficial effects (greater

Indirect, minor, short-term

effect on food source for

aquatic species. No

creation of in-water fish

Indirect, minor, short-term

effect on food source for

aquatic species; potential

beneficial effects from

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creation of some in-water

fish habitat.

than Alternative 1) from

creation of in-water fish

habitat.

habitat.

creation of in-water fish

habitat and/or beneficial

use that may restore

habitat.

Terrestrial

Resources

Indirect, minor effects on

terrestrial wildlife.

Minor, short-term, indirect

impacts on terrestrial

species through disruption

of habitat from levee raise.

Direct, long-term,

moderate effects to

terrestrial species from

loss of habitat at upland

disposal site and

disruption of habitat from

levee raise. Limited habitat

creation at disposal site.

Indirect, minor, short-term,

negative effects through

disruption of habitat from

levee raise; potential

long-term positive effects

from beneficial use of

dredged material to create

upland habitat.

Endangered

Species

Fish - Timing of

dredging and

disposal activities

minimizes impacts to

salmonids; some

habitat creation;

minor impact on Bull

Trout.

Terrestrial Wildlife -

Indirect, minor,

short-term effects on

Bald Eagle.

Plants - Minor

impacts anticipated.

Fish - Similar effects

as Alternative 1;

greater potential for

creation of salmonid

habitat.

Terrestrial Wildlife -

Indirect, minor,

short-term effect on

Bald Eagle.

Plants Minor impacts

anticipated.

Fish - Timing of

dredging minimizes

impact to salmonids;

minor impact on Bull

Trout. No salmonid

habitat created.

Terrestrial Wildlife -

Indirect, minor,

short-term effect on

Bald Eagle from

dredging and

disposal; direct,

long-term minor

impact on Bald Eagle

from upland

disposal.

Plants - No impacts

anticipated.

Fish - Timing of

dredging minimizes

impacts to

salmonids; minor

impact on Bull Trout.

Beneficial use

involving habitat

creation potential

beneficial to salmon.

Terrestrial Wildlife -

Indirect, minor,

short-term effect on

Bald Eagle from

dredging and

disposal; potential

indirect, positive

effect from beneficial

use of dredged

material.

Plants - No impacts

anticipated.

Recreation

Minor, short-term impact to

access to portions of the

river for recreational boats

near proposed dredging

and disposal activities.

Maintains ability to use

recreational facilities.

Minor, short-term, direct

impact due to disruption of

recreational facilities in

Lewiston area due to levee

raise, and minor short-term

impact to recreational

boating near dredging and

disposal.

Similar effects as

Alternative 2.

Similar effects as

Alternative 2. Potential

long-term, beneficial effect

from beneficial use of

dredged material if used to

enhance recreation sites.

Cultural Resources

Potential direct and

indirect effects to cultural

resources.

Similar effects as

Alternative 1.

Similar effects as

Alternative 1.

Similar effects as

Alternative 1.

Socio-Economics

Short-term, minor positive

effect from dredging and

disposal. Indirect,

long-term, moderate

negative effect from

greater potential flood risk

(no levee raise).

Direct, short-term and

long-term positive effect

from levee raise due to

added jobs and materials

required by levee

construction. Reduction of

flood risk from levee raise.

Direct, short-term and

long-term positive effect

from levee raise due to

added jobs and materials

required by levee

construction. Reduction of

flood risk from levee raise.

Direct, short-term and

long-term positive effect

from levee raise due to

added jobs and materials

required by levee

construction. Reduction of

flood risk from levee raise.

Transportation Maintains existing

transportation systems.

Direct, short-term, minor

effect on roadways from

proposed levee/road raise

construction activities.

Direct, short-term, minor

effect on roadways from

proposed levee/road raise

construction activities.

Direct, short-term, minor

effect on roadways from

proposed levee/road raise

construction activities.

Potential positive effect if

dredged material is used

for transportation projects.

Geology and Soils Local displacement of soil

and alluvial material.

Potential short-term effect

to soils in the vicinity of

levee raise due to

construction activities.

Potential short-term effect

to soils in the vicinity of

levee raise and upland

disposal site due to

construction activities.

Potential short-term effect

to soils from

implementation of

beneficial use due to

construction activities.

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Water

Quality/Water

Resources

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity.

Wetlands - No

effects.

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity.

Wetlands - No direct

effects.

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity.

Wetlands - No direct

effects.

Water Quality -

Direct, minor,

short-term effects

due primarily to

turbidity.

Wetlands - No

effects.

Hazardous and

Toxic Waste No effects anticipated. No effects anticipated.

No effect anticipated;

sediments will be tested

for contamination.

Same as Alternative 3.

Air Quality

Direct, minor, short-term

effects to local air quality

due to dredging and

disposal equipment

operation.

Direct, minor, short-term

effects to local air quality

due to dredging, disposal,

and construction

equipment operation.

Direct, minor, short-term

effects to local air quality

due to dredging, disposal,

and construction

equipment operation and

upland disposal activities.

Direct, minor, short-term

effects to local air quality

due to dredging, disposal,

and construction

equipment operation,

including implementation

of beneficial use(s).

Noise

Direct, minor, short-term

effects due to noise from

dredging and disposal

equipment operation.

Direct, minor, short-term

effects due to noise from

dredging and disposal

equipment operation.

Direct, minor, short-term

effects due to noise from

dredging and disposal

equipment operation.

Direct, minor, short-term

effects due to noise from

dredging and disposal

equipment operation.

Aesthetics

Direct, minor, short-term

effects on aesthetics due

to dredging and disposal

activities.

Direct, minor, short-term

effects on aesthetics due

to dredging and disposal

activities; long-term, minor

impacts from levee raise.

Direct, minor, short-term

effects from dredging.

Long-term, minor impacts

from levee raise. Direct,

minor, long-term effects

from upland disposal.

Direct, minor, short-term

effects on aesthetics due

to dredging and disposal;

long-term, minor impacts

from levee raise.

1"Impacts" and "effects" are used interchangeably. Unless otherwise noted as beneficial or positive, impacts described are negative.

4.1 AQUATIC RESOURCES

A number of management alternatives to alleviate the sediment accumulation in the navigation channel of the lower Snake River

reservoirs and McNary reservoir have been examined in the past. Most have involved removal of sediment through dredging with

either in-water or upland disposal. Habitat changes resulting from dredged material disposal can be either beneficial and increase

the suitability and availability of habitat for a given species, or can be detrimental and result in less suitable habitat. Improved

suitability can result in increased abundance and overall increased biological production, but conversely, decreased suitability can

result in decreased abundance or even extirpation of a species from a given area. (Bennett et al., 1997a and 1998)

4.1.1 Dredged Material Removal

Nearly all dredging would be completed mechanically using a clamshell bucket. Due to the characteristics of this equipment, it is

generally accepted that clamshell buckets do not have the potential to entrain fish. Specifically, the clamshell bucket descends to

the substrate in an open position. The force generated by the descent drives the jaws of the bucket into the substrate, which "bites"

the sediment upon retrieval. During the descent, the bucket cannot trap or contain a mobile organism because it is totally open.

Based on the operation of the clamshell dredge bucket, it is determined that the dredging operation should not entrain any

salmonid species.

The limited use of hydraulic dredging would be restricted to non-agitation suction type dredging and would be used only in

off-channel areas (such as HMU irrigation intakes). Hydraulic dredging can have direct impacts to fish and other aquatic organisms

by entrainment through the device itself. The timing of use and the use of other fish exclusion techniques (i.e., bubble curtains)

would substantially limit these impacts.

Dredging could cause temporary and localized impacts by increasing turbidity and suspended solids. However, the Corps

anticipates that, although dredging operations may create a detectable plume extending 1,000 feet (304.8 m) downstream, if

operations cause a 5-NTU increase over background (10 percent increase when background is over 50 NTUs) at a point 300 feet

(91.4 m) downstream, immediate actions would be taken to reduce the plume.

Ecologically, a number of benefits would accrue from dredging to the original river channel. Among those benefits would be the

maintenance of "original" riverine-like habitat for white sturgeon (Acipenser transmontanus) and production of riverine-like benthic

macroinvertebrates. To date, only one species of crayfish [the signal crayfish (Pacifastacus leniusculus)] has been found in Lower

Granite reservoir (Lepla, 1994; Anglea, 1997) and its habitat seems to be linked with substrate since it is a hiding species and not

burrowing. Lepla’s (1994) distribution of spatial abundance of white sturgeon was nearly identical to that for crayfish, an important

food item for white sturgeon in Lower Granite reservoir. Anglea (1997) and Naughton (1998) have both demonstrated that crayfish

constitute a significant dietary item for smallmouth bass (Micropterus dolomieui), and others (Bennett and Shrier, 1987; Bennett et

al., 1988; Chandler, 1993) have reported their significance as food for northern pike minnow (Ptychocheilus oregonensis) and

channel catfish (Ictalurus punctatus). In addition, several taxa of aquatic organisms commonly found in the stomachs of juvenile

anadromous salmonids in Lower Granite reservoir were from organisms produced on firm substrates (Karchesky, 1996). Hard

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substrata in lower Granite reservoir occur along riprap (Nightingale, 1999) and the original river channel. Therefore, dredging that

could improve the "natural" integrity of the bottom of the river channel in the upstream portion of Lower Granite reservoir and would

be beneficial to the production and potential availability of macroinvertebrates to fishes.

However, the upstream end of the reservoir is ecologically the most important habitat area of Lower Granite reservoir for both

resident fishes and food items for juvenile anadromous salmonids (Curet, 1994; Lepla, 1994). From a biological perspective,

repeated large volume dredging in the area identified for the expanded footprint would deleteriously affect the ecosystem. Effects

could include loss of benthic macroinvertebrate production and, in turn, loss of fish rearing habitat. Therefore, dredging alternatives

were limited to navigation maintenance.

In addition to material being removed from Lower Granite reservoir, various other locations would require dredging activity. The

approach to all navigation locks on the lower Snake River and the navigation channel at Schultz Bar would need to be dredged to

maintain navigation in the lower Snake River. Sites requiring material removal related to recreation include boat basins throughout

the project area and irrigation intakes at the HMUs maintained by the Corps. In addition, the channel providing navigation access to

local ports may also need to be dredged to maintain access to port facilities.

Dredging activities in backwater areas (HMUs and boat basins) would impact different species of fish at different times of the year.

During the summer months, dredging the backwater areas has a higher potential for impacting resident fish that prefer warmer

waters than the anadromous salmonids, which prefer cooler water. Curet (1994) reported that subyearling chinook salmon migrate

from shallow shoreline areas to deeper waters in the spring/summer when shoreline temperatures reach 64.4 "F (18 "C). Therefore,

summer dredging would have less potential to impact ESA-listed species occurring in boat basins and irrigation intakes. During the

winter, however, both resident and anadromous species have been identified as using backwater areas of McNary reservoir. Most of

the predatory resident fish component was comprised of introduced species, and salmonids were comprised of both yearling and

subyearling chinook (Easterbrooks, 1996). Presuming that the backwater areas of McNary reservoir are indicative of the project area

as a whole, dredging during the winter has a likelihood of adversely affecting these fish since they could be temporarily displaced

from those habitats. Dredging occurring in off-channel areas is not expected to enhance or negatively impact fish habitat.

4.1.2 Dredged Material Disposal

Beneficial use of dredged material, such as the proposed woody riparian habitat creation would potentially have benefits for aquatic

resources by providing structure and nutrients to the aquatic ecosystem. In-water beneficial disposal of dredged material in the

lower Snake River reservoirs is proposed to raise mid-water-depth benches in the reservoirs to shallow-water benches in an attempt

to create and enhance fish-rearing habitat. The goals are to provide physical habitat for various species, provide habitat for prey

items, and influence near-shore water temperatures to enhance rearing fish. After emergence and initial dispersal, subyearling

chinook salmon in both Lower Granite and Little Goose reservoirs have been collected over sand substrate and in areas of reduced

velocity (Curet, 1994). Beach seine haul sampling by Curet (1993) suggests that subyearling chinook salmon were concentrated

over suitable micro-habitats where conditions such as temperature and dissolved oxygen levels remain at levels conducive for

rearing. Bennett and Shrier (1986) and Bennett et al. (1988, 1990, 1991, 1993a, 1993b) captured subyearling chinook salmon over

low gradient, low velocity, sandy substrates in Lower Granite reservoir.

In addition, subyearling chinook salmon rearing along the shoreline of Lower Granite reservoir during the spring exhibit a strong

selection for substrata consisting of primarily sand and a moderate avoidance of cobble/sand and talus/sand (Curet, 1994). Creation

of shallow-water habitat is expected to enhance fall chinook rearing areas.

In-water disposal of dredged material can be designed to increase the abundance and availability of benthic macroinvertebrates to

various fish species. With the exception of oligochaete worms, benthic density decreases with depth (Pool and Ledgerwood, 1997).

Currently, greater than 90 percent of the habitat in Lower Granite reservoir (and likely the other lower Snake River reservoirs) is

considered either mid-depth [20 to 60 feet (6.1 to 18.3 m)] or deep water [greater than 60 feet (18.3 m)]. Therefore, by raising the

river bottom in some places, macroinvertebrate abundance could be enhanced in the lower Snake River. Bennett and Shrier (1987),

Bennett et al. (1988), and Karchesky (1996) clearly demonstrated the importance of benthic macroinvertebrates in Lower Granite

reservoir to downstream migrating salmonids. Dipterans (flies, mosquitoes, and midges) and ephemeropterans (mayflies) were

highly abundant in the stomachs of juvenile steelhead and chinook salmon in Lower Granite reservoir. However, Muir and Coley

(1996) showed that stomachs from a large proportion of juvenile salmonids collected at Lower Granite were empty, suggesting

either low food abundance near the dam or the lack of feeding. The morphometry of the area surrounding the forebay may be one

reason for the low presence of food in stomachs of juvenile salmonids collected at Lower Granite. The shoreline in the forebay is

steep and water depth is great [50 to 70 feet (15.2 to 21.3 m)]. Food abundance near the water surface is low and seems to be

limited to pupating and terrestrial insects that occupy the riprap used to protect the shoreline (Muir and Coley, 1996). Therefore,

dredged material might be effectively deposited to enhance the abundance and availability of benthic macroinvertebrates for food to

juvenile salmonids and bull trout in the forebay of Lower Granite and possibly other lower Snake River dams by decreasing water

depths and rearing areas for prey species.

Creating additional shallow-water habitat could increase the availability of warmer shallow waters in all of the lower Snake River

reservoirs. Currently, water temperatures are below optimum throughout the growing season for all resident game fish. Higher water

temperatures could enhance annual growth increments and possibly result in higher survival and higher standing crops. Curet

(1994) reported that subyearling chinook salmon migrate from shallow shoreline areas to deeper waters in the spring/summer when

shoreline temperatures reach 64.4 °F (18 °C). These data indicate that if shallow-water temperatures warmed earlier in the spring

up to 64.4 °F (18 °C), growth rates of subyearling chinook and possibly their survival might be enhanced by cuing them to outmigrate earlier in the season from the warmer shallow-water feeding areas during a time of cooler open water in the reservoirs.

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The process of upland disposal would require a dewatering process at the transfer station used to move the material from water to

land. The potential exists for effluent from dewatering to seep back into the river, possibly increasing turbidity in a localized area.

4.1.3 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Dredged material removal would be done by mechanical means during the winter in- water work window and would remove

sediments down to the depth of the original riverbed; the effects of dredging this template to these depths is considered positive on

the lower Snake River reservoirs. Sands, gravels and cobbles, expected to comprise 85 percent of the total material, would be

placed in water at mid-depth to form shallow-water habitat for rearing anadromous and resident fish. Shallow-water habitat would be

created wherever possible. No re-handling or reshaping of the disposed material would occur. Most of the material to be removed

from the McNary reservoir is silt and would be deposited in deep water downstream, close to McNary Dam.

4.1.3.1 Direct Effects

Dredging and disposal activities of alternative 1 are anticipated to have short-term, minor effects on aquatic species. The

macroinvertebrates in the dredged areas would be removed with the material and would then be redistributed or buried during the

disposal process. Those invertebrates at the disposal site would also be buried. These two actions would cause a temporary and

short- lived reduction in prey items for fish and crayfish at these two locations.

In most instances, mechanical removal methods would use a clamshell that has little to no opportunity to entrain fish. Both resident

and anadromous fish could use the area upstream and downstream of the sites where dredging and disposal activities would occur.

The dredging and disposal activities would not be a continuous activity confined to a single location and fish would return to the

activity areas shortly after completion of the project. Turbidity and water quality problems are expected to be minimal.

4.1.3.2 Indirect Effects

Recolonization by invertebrate specie s would follow completion of dredging at both the dredging and disposal areas.

Macroinvertebrate production would occur at both the dredge site location and on the disposed material during the following

growing season. These species would be available as food organisms to resident and anadromous fish in the following spring.

Creating shallow-water habitat with dredged material may attract resident and anadromous fish to shallower areas for rearing.

Continued in- water disposal as done in the past may provide areas of rearing for resident and anadromous fish and would provide

structural habitat for adult predacious fish in the lower Snake River system. Material dredged from the McNary reservoir would

contain invertebrates that would be redistributed at the disposal site in the lower reservoir. This may serve as a temporary food

source to rearing white sturgeon.

4.1.3.3 Summary

Of the alternatives involving in-water disposal, this alternative would provide the least potential benefit to increasing shallow-water

habitat for juvenile salmonids rearing in the McNary and lower Snake River reservoirs.

4.1.4 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

Dredging and disposal would be similar to that proposed in alternative 1. The primary differences with alternative 2 include the

3-foot (0.9-m) levee raise, the manner in which the disposed material would be placed, and the methods and time of year used to

accomplish the dredging. The 3-foot (0.9-m) levee raise would be performed outside of the wetted area of the river and would,

therefore, have little to no impact to aquatic species. The disposal of material would occur on mid-depth benches to raise the river

bottom, creating shallow-water habitat. The surfaces would be composed of sand and be smoothed over in an attempt to create

rearing habitat preferred by fall chinook salmon. The dredging options include using both mechanical and hydraulic dredging.

Mechanical dredging would be performed in most areas; however, in backwater areas when temperatures exceed 73 °F (22.7 °C),

hydraulic dredging could be used, primarily at irrigation intakes. Curet (1994) reported that subyearling chinook salmon migrate

from shallower shoreline areas when temperatures exceed 64.4 °F (18 °C). Therefore, when these fish are not using the backwater

areas, hydraulic dredging would have the least potential for entraining anadromous salmonids.

4.1.4.1 Direct Effects

Dredging and disposal activities are similar to alternative 1 and could have short-term, minor effects on aquatic species. The

macroinvertebrates in the dredged areas could be removed with the material and redistributed or buried during the disposal

process. Those invertebrates at the disposal site could be buried. These two actions could also cause a temporary and short- lived

reduction in prey items for fish and crayfish at these locations.

In most instances, mechanical removal methods would use a clamshell that has little to no opportunity to entrain fish. Hydraulic

dredging could occur in backwater areas during the warm-water work window; and, although salmonids should not be entrained,

this type of dredging may have a deleterious effect on resident fish (none of which are endangered or species of concern) that may

prefer these areas during higher temperatures. Both resident and anadromous fish could use the areas upstream and downstream

of the sites where dredging and disposal activities would occur. The dredging and disposal activities would not be a continuous

activity confined to a single location and fish would return to the activity areas shortly after completion of the project. Turbidity and

water quality problems are expected to be minimal since all dredging would occur during periods of low fish abundance.

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4.1.4.2 Indirect Effects

Indirect effects are similar to alternative 1, but with greater habitat enhancement potential. Creating shallow-water habitat would

attract resident and anadromous fish to shallower areas for rearing. In-water disposal meant to enhance fall chinook rearing areas

would provide areas of rearing for resident and anadromous fish and would limit the habitat for adult predacious fish in the lower

Snake River system. Few beneficial or detrimental effects would be expected in McNary reservoir.

Creating more shallow-water habitat could increase the availability of warmer shallow water in all of the lower Snake River reservoirs.

Currently, water temperatures are below optimum throughout the growing season fo r all resident game fish. Higher shallow-water

temperatures could enhance annual growth increments and possibly result in higher survival and higher standing crops of resident

or anadromous fish. Curet (1994) reported that subyearling fall chinook salmon migrate from shallow shoreline areas to deeper

waters in the spring/summer when shoreline temperatures attain 64.4 °F (18 °C). These data indicate that, if water temperatures

warmed earlier in the spring up to 64.4 °F (18 °C), growth rates of subyearling fall chinook and possibly their survival might be

enhanced by cuing them to out-migrate earlier in the season from the warmer shallow-water feeding areas during a time of cooler

open water in the reservoirs.

Recolonization by invertebrate species would follow completion of activities at both the dredging and disposal areas.

Macroinvertebrate production would occur at the dredge site location and on the disposed material during the following growing

season. These species would be available as food organisms to resident and anadromous fish in the following spring.

4.1.4.3 Summary

As with alternative 1, impacts to fish species as a result of dredging and in-water disposal would be short-term and minor, primarily

as a result of displacement during the dredging and disposal activities. The disposed dredged material would be shaped to provide

a smooth, sandy bottom with depths and slopes beneficial to fish rearing. Impacts to fish habitat could be long term and beneficial if

the dredged material is placed in shallow water. Monitoring of beneficial in-water disposal sites would be conducted to confirm the

effectiveness of habitat creation (see section 4.3.1.1.2).

4.1.5 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

The dredging activity associated with this alternative would have the same impacts as described for alternatives 1 and 2 in the

dredging areas. Although similar to alternative 2, the primary difference between alternatives 2 and 3 is the location of disposal

(upland versus in-water).

4.1.5.1 Direct Effects

The direct effects are similar to those discussed in alternative 2, including redistribution of invertebrates at the dredging site;

however, although aquatic invertebrates within the dredged material would be buried at the upland site, no aquatic invertebrates

would be buried at any in-water disposal site. In addition, no entrainment of salmonids would be expected and minimal entrainment

of resident fish would be expected.

4.1.5.2 Indirect Effects

The indirect effects of alternative 3 are similar to those in alternative 2, but without the additional benefits of the habitat

enhancement. By dredging down to hard substrate river bottom, macroinvertebrate production and diversity would be enhanced.

Thus, dredged material removal of accumulated sediments could have a positive effect.

The levee raise would occur on the adjacent uplands. The nominal 3-foot (0.9-m) levee raise would have no impact on aquatic

species.

No aquatic ecological benefits would accrue from upland disposal. The process of upland disposal would require a dewatering

process at the transfer station used to move the material from water to land. The potential exists for effluent from dewatering to seep

back into the river, possibly increasing turbidity in a localized area.

4.1.5.3 Summary

As with alternatives 1 and 2, impacts to fish species as a result of dredging and in-water disposal would be short-term and minor,

primarily as a result of displacement during the dredging and disposal activities. No long-term and beneficial results for aquatic

habitat would occur with upland disposal.

4.1.6 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

Dredging and disposal would be similar to that proposed in alternative 2. The primary differences between alternatives 2 and 4

include the manner in which the disposed material would be used. The 3-foot (0.9-m) levee raise would be performed outside of the

wetted area of the river and would, therefore, have little to no impact to aquatic species. The disposal of dredged material could be

used to create mid-depth-water benches to raise the river bottom, creating shallow-water habitat. The surfaces would be composed

of sand and be smoothed over in an attempt to create rearing habitat preferred by fall chinook salmon. The dredging options

include using both mechanical and hydraulic dredging. Mechanical dredging would be performed in most areas; however,

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mechanical or hydraulic dredging could be used in backwater areas when temperatures exceed 73 °F (22.7°C) or when it can be

documented that ESA-listed fish would not be present.

This alternative states that dredged material would be put to beneficial use, and alternative 2 states that in-water disposal to create

fish habitat would be used. These two options, although apparently similar, have some major differences. In alternative 2, all

disposal of material (with exception of contaminated material) would occur in-water and would be used to create fish habitat. In

alternative 4, in- water would be one disposal method, but other methods would also be considered. Initially, the proposed

beneficial use would be creation of woody riparian habitat in shoreline areas of Chief Timothy HMU and possibly other areas along

the lower Snake River, as described in Section 1.8. Members of the LSMG would be able to suggest other beneficial uses of the

material, including fill of land and ports, capping areas in need of topsoil, creating or restoring riparian areas, and use of silt in

industrial practices such as making potting soil.

4.1.6.1 Direct Effects

Dredging and disposal activities are assumed to be similar to alternative 2 and could have short-term, minor effects on aquatic

species. The macroinvertebrates in the dredged areas would be removed with the material and redistributed or buried during the

disposal process. Those invertebrates at the disposal site could be buried. These two actions could also cause a temporary and

short- lived reduction in prey items for fish and crayfish at these locations.

In most instances, mechanical removal methods would use a clamshell that has little to no opportunity to entrain fish. Hydraulic

dredging could occur in backwater areas and, although salmonids should not be entrained, this type of dredging may have a

deleterious effect on resident fish (none of which are endangered or species of concern) that may prefer these areas. Both resident

and anadromous fish could use the areas upstream and downs tream of the sites where dredging and disposal activities would

occur. The dredging and disposal activities would not be a continuous activity confined to a single location. Fish would return to the

activity areas shortly after completion of the project. Turbidity and water quality problems are expected to be minimal since all

dredging would occur during periods of low fish abundance.

Creation of woody riparian habitat would involve placement of dredged materials in shoreline areas of the lower Snake River. This

would have long-term positive effects for aquatic resources. Placement of dredged material in- water to create fish habitat would

have similar effects to alternative 2.

4.1.6.2 Indirect Effects

Indirect effects are similar to alternative 2. Creating shallow-water habitat may attract resident and anadromous fish to shallower

areas for rearing. In-water disposal meant to enhance fall chinook rearing areas would not only provide areas of rearing for resident

and anadromous fish but also would limit the habitat for adult predacious fish in the lower Snake River System. Recolonization by

invertebrate species would follow completion of dredging at both the dredging and disposal areas. Macroinvertebrate production

would occur at the dredge site location and on the disposed material during the following growing season. These species would be

available as food organisms to resident and anadromous fish in the following spring. Any creation or restoration of riparian zones,

such as the proposed woody riparian habitat program at Chief Timothy HMU, would also be beneficial to fish by creating a more

natural shoreline conducive to food production.

4.1.6.3 Summary

As with alternative 2, impacts to fish species as a result of dredging and riparian habit at creation, as well as in-water disposal,

would be short-term and minor, primarily as a result of displacement during the dredging and disposal activities. Restoration of

riparian zones would be conducive to restoring fish habitat, as it would provide structure and nutrients that are beneficial to the

aquatic ecosystem. If the disposed dredged material were placed in water, it would be shaped to provide a relatively smooth bottom

with depths and slopes beneficial to fish rearing. Impacts to fish habitat could be long-term and beneficial. Monitoring of beneficial

in-water disposal sites would be conducted to confirm the effectiveness of habitat creation (see section 4.3.1.1).

4.1.7 Critical Habitat Considerations

The project area is designated to be Critical Habitat for all four Snake River salmon ESU stocks, Upper Columbia River Spring-Run

Chinook Salmon, and for Snake River, Middle Columbia, and Upper Columbia Basin steelhead. In designating Critical Habitat,

NMFS considers the following requirements of the species: (1) space for individual and population growth, and for normal behavior;

(2) food, water, air, light, minerals, or other nutritional or physiological requirements; (3) cover or shelter; (4) sites for breeding,

reproduction, or rearing of offspring; and, generally, (5) habitats that are protected from disturbance or are representative of

historical geographical and ecological distributions of the species.

In addition to these factors, NMFS also focuses on the known physical and biological features (primary constituent elements) within

the designated area that are essential to the conservation of the species and that may require special management considerations

or protection, termed Essential Fish Habitat (EFH) pursuant to the Magnuson-Stevens Fishery Conservation and Management Act,

16 U.S.C. 1801 et seq. These essential features may include, but are not limited to, spawning sites, food resources, water quality

and quantity, and riparian vegetation [50 CFR 424.12(b)], and can be generally described to include the following: (1) juvenile

rearing areas; (2) juvenile migration corridors; (3) areas for growth and development to adulthood; (4) adult migration corridors; and

(5) spawning areas. Within these areas, essential features of Critical Habitat include adequate: (1) substrate, (2) water quality, (3)

water quantity, (4) water temperature, (5) water velocity, (6) cover/shelter, (7) food, (8) riparian vegetation, (9) space, and (10) safe

passage conditions. Adjacent riparian area is defined by NMFS as the area adjacent to a stream (river) that provides the following

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functions [components of Properly Functioning Habitat or Properly Functioning Condition]: shade, sediment transport, nutrient or

chemical regulation, streambank stability, and input of large woody debris or organic matter.

Section 9 of the ESA makes it illegal to "take" a threatened or endangered species of fish. The definition of “take” is to “harass,

harm, pursue, hunt, shoot, wound, kill, trap, capture, or collect, or to attempt to engage in any such conduct” (16 U.S.C. 1532(19)).

The NMFS interprets the term "harm" in the context of habitat destruction through modification or degradation as an act that actually

kills or injures fish.

Table 4-2 and visual surveys of 1934 sounding data used to recreate the pre-dam lower Snake River channel demonstrate that an

unimpounded large class river is primarily composed of greater than 70 percent shallow-water habitat in the form of opposing

deposition bars of sand for most flow years, and at least 50 to 60 percent shallow-water habitat for very high flow years where

possibly 10 percent of the lower Snake River could constitute deep water. The pooling of Lower Granite reservoir in 1975 inundated

the historical shallow-water habitat, thus converting approximately 40 to 60 percent of the shallow-water sand bar habitat used by

juvenile fall chinook salmon into mid-depth bench habitat more suitable for white sturgeon (if no additional structural cover is

provided in the substrate) or adults of resident predator species (if additional structural cover is provided in the substrate) or

deep-water habitat utilized by few species (e.g., channel catfish). An analysis of limiting conditions for reservoir-wide habitat readily

indicates that shallow-water habitat composed of low gradient, open sand with no additional cover structure (e.g., opposing sand

bars) suitable for and replicative of fall chinook salmon rearing habitat should be a main objective for maximizing beneficial use of

in-water disposal of dredged material.

Table 4-2

Quantification of Three Water Depth Habitats

In Lower Granite Reservoir, Snake River (SR), and Clearwater River (CR)

During The Early- to Mid-1980s1

Reservoir

Reach

(River Mile)

Shallow

[<20 feet (6.1m)]

Acres/Hectares

(Percent)

Mid-Depth

[20-60 feet

(6.1-18.3 m)]

Acres/Hectares

(Percent)

Deep

[>60 feet (18.3

m)]

Acres/Hectares

(Percent)

Total

Acres/Hectares

(Percent of Total

Reservoir or

Reach)

SR 107.4 - SR 120.46 281/113.7 (8%) 1,241/502.2 (34%) 2,147/868.9 (57%) 3,669/484.8 (43%)

SR 120.46 - SR 146.33 983/397.8 (8%) 2,795/1 131.1

(58%) 1,017/411.6 (21%) 4,795/1 940.5(57%)

SR 107.4 - SR 146.33 1,264/511.5 (15%) 4,036/1 633.3

(48%)

3,164/1 280.4

(37%)

8,464/3 425.3

(94%)

CR 0.0 - CR 4.4 349/141.2 (71%) 141/57.1 (29%) 0/0 (0%) 489/197.9 (6%)

SR 107.4 - SR 146.33 and CR 0.0 - CR 4.4 1,612/652.4 (18%) 4,177/1 690.4

(47%)

3,164/1 280.4

(35%)

8,953/3 623.2

(100%)

1Estimates calculated from U.S. Army Corps of Engineers cross section profiles. SR 120.46 is the mid-reservoir section where the majority of the fine silt and sand material settles out due to increased rate of

depth affecting the slowing rate of water velocity.

To determine the minimum surface acreage of habitats to be created, pre- impoundment aerial photos of the shorelines of the lower

Snake River were studied and the sandy, shallow-water areas conducive to rearing fall chinook salmon were measured. Historically,

a wide size range of these habitats existed but a minimum surface area for shallow-water habitat creation was designated as 4 acres

(1.6 hectares). This acreage was actually lower than the average habitat area found pre- impoundment, but was calculated as the

minimum necessary to attempt to mimic the free- flowing shoreline habitat required by fall chinook salmon.

Apart from this comparison between the abundance and suitability of historical versus existing shallow-water sandbar habitat, very

few of the EFH components that existed along the shoreline of the lower Snake River reservoirs have been modified or eliminated in

the recent past due to previous maintenance dredging, where other associated human activities and economic growth along the

shorelines have resulted in some modification of habitat that introduced additional needs for dredging. The two EFH components

that may have been potentially influenced by confluence dredging in the past are juvenile migration corridor and adult migration

corridor, specifically the essential features of substrate, water quality, food (as in macroinvertebrate production), and safe passage

conditions. Adjacent to the footprint boundary for dredging in the confluence is a critically important juvenile rearing area for fall

chinook salmon in the embayment of Wilma. The existing open, sandy, shallow-water rearing habitat within Wilma remains

protected from modification of any bathymetric feature that would be due to proposed dredging and, therefore, would not be

affected by the dredging proposed to occur in the main stem channel. Dredging activities would be confined to the in- water work

window when no or very few salmonids would be migrating or requiring pre- migration rearing, so exposure to short-term increases

in turbidity should not exist. Dredging is not allowed at elevations below the existing channel bottom contours because removal of

input sand and silt is the target; hence, native substrate classes of cobble and gravel suitable for spawning should not be affected.

It has been routinely shown that macroinvertebrates displaced by dredged material removal aid in colonizing or supplementing

existing populations at the in-water disposal sites and that the populations at the removal site become recolonized relatively rapidly

depending upon season (Bennett et al., 1990, 1991, 1993a, 1993b, 1995a, 1995b; Bennett and Nightingale, 1994), both influenced

through the mechanism of drift.

The EFH components that may be potentially influenced by dredging in the boat basins or their approaches from the main channel

are juvenile rearing areas, juvenile migration corridors, and adult migration corridors (specifically the essential features of substrate,

water quality, water velocity, food (as in macroinvertebrate production), and safe passage conditions. Boat basins and HMU water

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intake basins fill with fine substrate dominated by silt that is not suitable substrate preferred by salmonids. High use by recreational

boat traffic can limit their suitability for salmonid rearing. Dredging activities would be conducted during both the winter in-water

work window and during the summer if water temperatures exceed 73 °F (22.7 °C). Few to no salmonids would be expected to

occur in backwater areas during both of these time periods, so exposure to short-term increases in turbidity would either not exist or

would have a minimal effect. These areas would be dredged primarily by mechanical means; however, limited amounts of hydraulic

dredging may occur during periods of warm water when salmonids would not be present. Water velocities would not be affected

since these areas are functionally shallow water back eddies more suitable for resident fish. Macroinvertebrates displaced by

dredged material removal can aid in colonizing or supplementing existing populations at the in-water disposal sites and the

populations at the removal site become recolonized relatively rapidly depending upon season. An additional concern with the

substrate quality removed from boat basins that have not been dredged in a number of years is the potential for the accumulation of

bound contaminants in the silt as a result of spillage from fueling or other activities, or brought downriver to settle in the lower

velocities of the backwater eddy environment. Recent sampling in these basins indicates that concentrations of contaminant

indicators are below the level that would preclude their disposal in-water. In the event that a pocket of visually contaminated

sediments is hauled up in the clamshell or bucket, the Corps would direct that area be classified and investigated as HTRW and

deposited in a truck for removal to an appropriate established waste disposal site.

The EFH component that may be potentially influenced by dredging in the lock approaches of Lower Granite and Lower

Monumental, which are spawning areas, specifically concerns the essential features of substrate, water velocity, cover/shelter, and

possibly food (as in macroinvertebrate production). Prior to dredging, these areas would be surveyed for redds according to

established protocol (Dauble et al., 1995) to determine if modifications to velocity and substrate could cause salmon to avoid these

areas for spawning. If redds are found and verified, then location and duration of dredging would be modified to accommodate

avoidance and protection of any verified redds.

The Corps believes that periodic maintenance dredging performed on a schedule of every 2 to 3 years and contained entirely within

the previously disturbed footprint would not degrade the suitability of that habitat for Snake River Basin Sockeye, Snake River

spring/summer and/or fall chinook salmon, Snake and/or Middle Columbia and/or upper Columbia River Basin steelhead, or Upper

Columbia River Spring- Run Chinook salmon, thus not adversely modifying Critical Habitat or EFH components of that Critical

Habitat. This is because the area is used primarily as a migration corridor for all life stages of these stocks and migration of each life

stage of each stock has terminated for the brood years, with the exception of potential for utilization of the submerged shallow water

for rearing and feeding by fall chinook and some adult migration by B-run steelhead to upriver tributaries to hold for spawning in the

following spring. None of the known or potential areas used by fall chinook salmon for rearing would be disturbed by any dredged

material removal action.

4.1.8 Mitigation

Dredging would remove macroinvertebrate prey species within the dredging template. Recolonization would occur at the dredging

site within a few months (during the next growing season). Alternative 2, to a lesser extent alternative 1, and the fish habitat creation

and riparian habitat creation beneficial uses proposed in alternative 4, would reposition these materials to locations within the

reservoirs that would allow for additional macroinvertebrate production. Prey availability would increase for juvenile out-migrating

salmonids and bull trout at the disposal locations.

Dredging to the natural river channel and in-water disposal would improve habitat conditions by providing habitat more conducive to

additional prey species production. In order to avoid direct impacts such as entrainment of juvenile salmonids, dredging and

disposal activities would occur when salmonid species are less likely to be present.

The disturbance of silt during dredging and the discharge of dredged material have the potential to impact listed species. However,

the disturbance caused by the mechanical dredge as it enters the water and removes material would tend to cause any listed

species present to leave the dredging area. The engine noise from the tugboat pulling the transport barge may cause fish to move

away as the barge approaches the disposal site. Fish are known to respond evasively to a variety of stimuli (Popper and Carlson,

1998). Except in the very shallow disposal sites, the sudden stimulus of the nose or shock wave associated with the release of the

dredged material or the sudden decrease in light would be expected to startle fish and induce them to dart away from the source

(Anderson, 1990).

In addition to ESA consultation with the USFWS, the LSMG would, on a case-by-case basis, evaluate the potential for impacts to

bull trout and other listed species. Depending upon the location, the quantity of material to be dredged, and the proposed disposal

location, modifications to the typical "fish window" may be considered.

4.2 TERRESTRIAL RESOURCES

4.2.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

For the navigation project, a 14-foot (4.3-m) channel with at least 15 feet (4.3 m) over the sills at each of the locks and 14-footby-250-foot (4.3- m-by-76.2-m) channels providing access to port and barge loading facilities in each reservoir will be provided. For

the dredging in the Lower Granite reservoir, dredged materials would continue to be disposed of near Centennial Island in shallow

water [15 to 35 feet (4.6 to 10.7 m)] and at mid-depth [35 to 63 feet (10.7 to 19.2 m)] and deep water [greater than 63 feet (19.2 m)].

For the remaining three reservoirs on the lower Snake River, dredged material would continue to be disposed of in deep water,

mid-depth water, and near-shore water. Habitat has been and would continue to be created or enhanced. For example, in McNary

reservoir, dredged materials have been used in the past to create islands and to enhance wildlife habitat.

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Dredging and disposal actions within and adjacent to the river would not prevent wildlife from obtaining food from adjacent areas.

No trees would be removed; therefore, streamside and shoreline perch trees would not be impacted. Waterfowl, fish, and other

wildlife would use the areas above and below the sites where dredging and disposal activities occur. The dredging and disposal

activities would not be a continuous activity confined to a single location. Waterfowl, fish, and other wildlife would retur n to the

activity areas shortly after completion of the project.

Similarly, aquatic furbearers that occur at or near the dredging or disposal site vicinity have not been adversely impacted by past

dredging and disposal activities. They have been and would continue to be deterred from using the sites during the dredging,

transport, and disposal activity but would continue to use adjacent areas during dredging/disposal activities.

Other mammals, such as mule deer, would not be impacted by this alternative since there would be no impacts to existing uplands.

In summary, dredging and disposal activities under alternative 1 would have indirect, short-term, minor effects on terrestrial wildlife

and habitat.

4.2.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat and a 3-Foot (0.9-m) Levee Raise

As noted above, impacts to terrestrial species as a result of the dredging and in- water disposal would be indirect and minor,

primarily as a result of displacement during the operation. With completion of the dredging and disposal activities, wildlife and

waterfowl displaced by the activities would return.

For this alternative, material unsuitable for beneficial use or in-water disposal would be isolated at the Joso upland disposal site and

appropriate confinement measures would be taken to isolate this material (i.e., an impervious liner). The barge facility for offloading these dredged materials would be located at the west end of the site. The disposal site at Joso is contained primarily within

an abandoned gravel quarry, used during the construction of Lower Monumental reservoir. The total impact area would be

approximately 100 acres (40.5 hectares). Wildlife using this area would be displaced from the barge facility area and the disposal

area during construction and operation of the facility. The facility would not be used continuously and some wildlife and waterfowl

would return to the area during the months and years when dredging and disposal activities were not occurring. Depending upon

the quantity of material requiring disposal, some poor-quality, previously disturbed upland habitat would be lost in the quarry area.

Disturbances caused by noise and general activity during disposal activity may cause more sensitive species to abandon the site.

Upland disposal at Joso is expected to have a direct, long-term, moderate impact on terrestrial wildlife. The disposal area will be

planted to native vegetation, which would benefit terrestrial wildlife in the future.

The proposed 3-foot (0.9-m) levee raise would similarly have minimal, indirect, temporary impacts on terrestrial species.

Construction could disturb wildlife. However, the areas proposed for the levee raise are in an urban setting and only those species

accustomed to human activity would be present. The levee raise would be placed atop the existing levee. Revegetation would result

in habitat similar to existing conditions.

4.2.3 Alternative 3 - Maintenance Dredging With Upland Disposal

and a 3-Foot (0.9-m) Levee Raise

The dredging activity associated with this alternative would have the same impact as described for alternatives 1 and 2. Some

displacement of waterfowl and aquatic furbearers from the dredging area could occur. Long-term impacts would not occur.

Disposal of dredged material would occur at the Joso site on the Snake River below Little Goose. The entire site is approximately

568 acres (229.9 hectares), with open space/wildlife habitat management being the present use. Barge access to the Joso site

would be at the west end, providing access to a disposal area of approximately 280 acres (113.3 hectares) located in the center of

the site with 600-foot (182.9- m) buffers from the river. Part of the disposal area is a disturbed site that was historically used for

gravel extraction and currently contains an exposed open gravel quarry. This action would also disturb approximate 190 acres (76.9

hectares) of upland habitat outside of the quarry by direct deposition of dredged material on top of the existing vegetation. Less

than 2 acres (0.8 hectare) of riparian habitat would be removed to construct this barge off- loading facility. Wildlife using these areas

would be displaced from the barge facility area and the disposal area during construction and operation and some species may be

displaced permanently. The 600- foot (182.9-hectare) buffer along the shoreline would continue to provide habitat; however,

disturbances during disposal activity may cause more sensitive species to abandon the site.

The area would be stabilized following each dredging cycle and would be recontoured and restored with native plantings following

completion of all dredging over the next 20 years. With completion of the disposal and revegetation, the site would revert to wildlife

habitat similar to the surrounding area. Upland disposal at Joso is expected to have a direct, long-term, moderate impact on

terrestrial wildlife. The impacts would be from dredged material storage activities at the site over the next 20 years. Habitat would

also be decreased as the dredged material storage expands across the impact area. There would also be a time lag of 5 to 7 years

where habitat once available would be either unvegetated or in the early regrowth stages after restoration. If restoration progresses

as areas are filled, developed habitat would still be fragmented until all work ceases after 20 years.

As with alternative 2, dredged materials unsuitable for in-water disposal or beneficial use would be isolated and appropriate

confinement measures taken (e.g., an impervious liner installed to prevent leaching).

The impact of the 3-foot (0.9-m) levee raise would be similar to alternative 2.

4.2.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

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and a 3-Foot (0.9-m) Levee Raise

The dredging activity associated with this alternative would have the same impact as described for alternatives 1, 2, and 3.

Disposal activities would have varying impacts to terrestrial species, depending upon which beneficial use was used for a particular

dredging activity. The proposed woody riparian habitat creation would have a short-term direct impact on terrestrial wildlife in the

vicinity of the selected sites. However, creation of woody riparian habitat would provide long-term benefits for terrestrial wildlife by

creating additional habitat consistent with the Lower Snake River Fish and Wildlife Compensation Plan. If in-water disposal to create

fish habitat were selected as the disposal option, impacts to terrestrial species would be similar to those for alternative 2. If riparian

habitat restoration were selected, species dependent upon riparian vegetation would benefit the most. Fill activities on upland sites

may have adverse impacts to terrestrial species. Potential impacts to terrestrial species would be considered prior to the selection of

a beneficial use.

Impacts to Joso as a result of disposal of unsuitable dredged material would be the same as for alternatives 2 or 3.

4.2.5 Mitigation

With the exception of alternative 3 and upland disposal of some of the dredged material at Joso, the impacts to terrestrial species

would be minimal and short-term. Mitigation for alternatives 1, 2, and 4 is not necessary since impacts to existing habitat are minimal

and the future habitat would be enhanced after dredging and disposal activities are completed. Alternative 3 involves direct,

long-term, moderate impact to an HMU. The HMUs were developed to mitigate for habitat loss due to the inundation of lands behind

dams. These lands are designated for wildlife habitat protection and enhancement under the Lower Snake River Fish and Wildlife

Compensation Plan (Corps, 1999b). Existing habitat is a part of those contributing to the total habitat value calculated for the lower

Snake River (Sather-Blair et al., 1991). Shrub-steppe, grassland, and forbland habitats are found within the potential impact area

under alternative 3. Although, the site would be restored after the dredging cycle is completed, interim compensation for lost habitat

may still be needed. The interim loss of 190 acres (76.9 hectares) of upland habitat could be compensated by replacement through

the purchase of new land.

Mitigation/replacement of the upland and riparian vegetation would be coordinated with the WDFW and USFWS. A revegetation

planting and monitoring plan would be prepared for review and comment. This plan would be the basis for site restoration. The plan

would be developed following final selection of the Joso site as the preferred disposal site. For Joso, the disposal area could be

contoured and restored as cells are completed. This would be a long-term mitigation program depending upon the amount of

material that is disposed of annually.

4.3 ENDANGERED SPECIES

4.3.1 Fish

4.3.1.1 Anadromous Fish

The Corps consulted with NMFS and prepared a Biological Assessment for the proposed dredging and dredged material

management activities documented in the DMMP/EIS (see appendix F). NMFS determined that, based upon implementation of a

series of Reasonable and Prudent Measures, the proposed actions would not cause jeopardy to, or adversely modify the Critical

Habitat of anadromous fish species listed under the Endangered Species Act (ESA).

4.3.1.1.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

The ESA-listed anadromous fish known to occur in the proposed project area include Snake River Basin Spring/Summer, and Fall

chinook salmon; Sockeye salmon; and steelhead. In addition, Middle Columbia Steelhead, Upper Columbia steelhead, and Upper

Columbia Spring Chinook salmon are expected to occur in McNary reservoir. The ESA-listed anadromous salmonid species using

the existing shallow-water habitat would be primarily Snake River fall chinook salmon. The main benefits of this alternative are that

dredging would restore hard substrate for prey production and would create shallow-water habitat. This alternative provides the

least potential benefit to increasing habitat for fall chinook salmon rearing in the McNary and lower Snake River reservoirs since they

prefer smooth sandy substrates. A review of potential impacts to fall chinook salmon is presented in section 4.1.2. Because of the

potential for individuals of ESA- listed salmonids to exist within the dredging and disposal areas year round, it was determined that

this alternative "may affect and would likely adversely affect" six of the seven above-listed salmonid ESUs. The exception would be

the Snake River Sockeye salmon, which have not been documented in the main stem Snake or Columbia Rivers or its backwaters

outside of the normal migratory windows.

4.3.1.1.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

As discussed in section 4.1.4, this alternative would provide the opportunity to develop shallow-water habitat throughout the project

area. This alternative "may affect and would likely adversely affect” six of the seven ESA- listed salmonid ESUs (with the exception

of sockeye salmon) similar to alt ernatives 1 and 4. To confirm the effectiveness of habitat creation, biological monitoring would be

conducted in accordance with the mitigation plan.

4.3.1.1.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

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As noted in section 4.1.5, the dredging activity associated with this alternative would have the same impacts as described for

alternatives 1 and 2 in the dredging areas but no beneficial shallow-water habitat would be created. This alternative "may affect and

would likely adversely affect" six of the seven ESA-listed salmonid ESUs with the exception of sockeye salmon.

4.3.1.1.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

The impacts to listed anadromous fish species from this alternative are discussed in section 4.1.6.

A number of beneficial uses are discussed in section 2.5.4. These include:

Woody Riparian Habitat Creation – This is the proposed beneficial use that would be implemented during the initial years of

the DMMP. This program would establish woody riparian habitat in shoreline areas of Chief Timothy HMU in Lower Granite

Reservoir and possibly other sites along the lower Snake River. The Corps would evaluate the areas of proposed dredged

material placement to ensure that fish habitat would not be disturbed and would monitor the success of the habitat creation

and, if appropriate, propose additional areas where this beneficial use of dredged material could occur.

Hanford Capping - This use would improve the dredged area by providing hard substrate for prey species. No benefit for listed

aquatic species would be accrued by disposal since the dredged material would be placed on uplands.

Potting Soil- Impacts from this use would also be beneficial at the dredge location. No benefit would be derived for listed

aquatic species from the disposal of dredged material.

Riparian Habitat Restoration -This use would have similar impacts at the dredge site location. The dredged material would be

used to create shallow shoreline areas. These new shoreline areas would provide additional rearing and feeding habitat for

listed species.

Port of Wilma Fill - Dredging would provide hard substrate for prey species. The dredged material would be removed from use

for habitat creation and, thus, no benefit would be realized from disposal.

Fill of Non-Federal Public Land - Benefits from dredging would be realized. The location and nature of the fill activity is not yet

defined; however, the range of impacts would be similar to those above. If shallow-water habitat is created by the fill, the

activity would be beneficial to listed species. Conversely, since upland areas are filled, no benefit to aquatic habitat from

disposal would be realized.

Lower Granite SR193/SR194 Road Connection - A number of alternative alignments have been considered. Depending on the

alternative selected, some shallow-water habitat could be created that would be beneficial to listed species.

Research of Beneficial Uses - Two research groups at the Corps Waterway Experiment Station are investigating measures to

use fine-grained sediment suitable for use as a top dressing and habitat restoration.

Each of these beneficial uses would have a positive impact on listed species and their prey organisms as a result of dredging. As

pointed out above, some of these proposed uses would also create shallow-water habitat. However, due to the potential for direct

impacts to anadromous fish, this alternative "may affect and would likely adversely affect" six of the seven listed salmonid ESUs

(except Sockeye salmon). This determination would be reevaluated as specific actions are selected. However, the NMFS has

determined that the effects of the proposed actions will not jeopardize the cont inued existence of endangered SR sockeye,

threatened SRF chinook, threatened SRSS chinook, threatened SRB steelhead, endangered UCRS chinook, endangered UCR

steelhead, or threatened MCR steelhead or result in the adverse modification or destruction of their Critical Habitat. The

determination of no jeopardy is based upon the current status of the species, the environmental baseline for the action area, and

the effects of the proposed actions (Appendix F).

4.3.1.2 Resident Fish

The Corps has conferred with the U.S. Fish and Wildlife Service (USFWS) and prepared a Biological Assessment (BA) regarding

listed fish species that fall within their jurisdiction (i.e., resident, non-anadromous fish). The Biological Assessment and the USFWS’

concurrence letters are presented in appendix G. The BA findings for each alternative are summarized below.

4.3.1.2.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Bull trout (Salvelinus confluentus) generally are not found in the main stem Snake River, preferring colder water and gravelly

substrate. The main subpopulation of bull trout associated with the four lower Snake River reservoirs spawns and rears in the

Tucannon River Basin. Both resident and migratory forms occur there. They have been reported in the Clearwater River, although in

the headwaters upstream of the project area (Bowerman et al., 1998). A very limited number have also been reported in the Snake

River. Hayley (1999) noted 37 records of bull trout in the lower Snake River since 1991. Most were noted at adult fish counting

stations at the dams and passed in April, May, or June.

The disturbance of silt during dredging and the discharge of dredged material have the potential to impact bull trout. However, the

disturbance caused by the mechanical dredge as it enters the water and removes material would tend to cause any bull trout

present to leave the dredging area. The engine noise from the tugboat pulling the transport barge may cause fish to move away as

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the barge approaches the disposal site. Fish are known to respond evasively to a variety of stimuli (Popper and Carlson, 1998).

Except in the very shallow disposal sites, the sudden stimulus of the nose or shock wave associated with the release of the dredged

material or the sudden decrease in light would be expected to startle fish and induce them to dart away from the source (Anderson,

1990).

Although bull trout have been reported in the Snake River only during April, May, and June, it should be noted that the counting

stations are closed during the winter months and thus bull trout could be present during the dredging and disposal periods.

Therefore, alternative 1 could have an impact on bull trout in select locations within the project area (i.e., near the Tucannon River).

Bull trout are least likely to be present during times of highest main stem water temperatures (late summer).

Dredging would be completed using mechanical means, primarily by means of a clamshell. Due to the characteristics of this

equipment, it is generally accepted that clamshell buckets do not have the potential to entrain fish. Specifically, the clamshell

bucket descends to the substrate in an open position. The force generated by the descent drives the jaws of the bucket into the

substrate, which "bites" the sediment upon retrieval. During the descent, the bucket cannot trap or contain a mobile organism

because it is totally open. Based on the operation of the clamshell dredge bucket, it is determined that the dredging operation

should not entrain bull trout.

Dredging and disposal would cause temporary and localized impacts by increasing turbidity and suspended solids. The Corps

anticipates dredging operations may create a detectable plume extending 1,000 feet (304.8 m) downstream. Sho uld dredging and

disposal operations cause more than a 5-NTU increase over background (10 percent increase when background is over 50 NTU's)

at a point more than 300 feet (91.4 m) downstream, immediate actions would be taken to reduce the plume. Background turbidities

in the lower Snake River reservoirs and McNary reservoir, generally do not exceed 10 NTU's (Corps, 1999). Van Oosten (1945)

concluded from a literature survey that average turbidities as high as 200 NTU's are harmless to fish. Based on the disparity

between the turbidity increases anticipated as part of the dredging and disposal operation and the levels reported to be harmful to

fish, it is determined that the dredging and disposal operations would not effect bull trout as a result of increased turbidity.

The likelihood of bull trout being in the project(s) location is remote. The ability of fish to avoid high turbidity and clamshell dredge

equipment suggests that bull trout, if they were to occur in the action area, would not be entrained by dredging and disposal

activities. Thus, this alternative "may affect but is not likely to adversely affect" bull trout.

4.3.1.2.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

Impacts would be similar to alternative 1. Bull trout occurrence in the dredging and disposal areas, while possible, would be very

unlikely. Should the Corps use hydraulic dredging at irrigation intakes in the summer, bull trout would not likely be in the vicinity of

the dredging since the intakes would be in isolated locations with water temperatures high enough to exclude bull trout. If the water

temperatures were not high enough to exclude bull trout, bubble curtains could be employed to scare fish away from the dredging

zone. Use of hydraulic dredging at a particular site would be coordinated with USFWS prior to the start of dredging. This alternative

could be used to enhance habitat potentially used by bull trout. Although they are very rare in the Snake River, creation of

shallow-water habitat could provide impact. Thus, beneficial uses could have a positive effect on bull trout. The alternative "may

effect but is not likely to adversely effect" bull trout.

4.3.1.2.3 Alternative 3 - Maintenance Dredging With Upland Disposal

and a 3-Foot (0.9-m) Levee Raise

Impacts would be similar to alternatives 1 and 2 for bull trout. Upland disposal and the levee raise would have no direct impact on

bull trout. The alternative "may affect but is not likely to adversely affect" bull trout.

4.3.1.2.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

The dredging activity associated with this alternative would have the same impact as described for alternatives 1, 2, and 3.

Disposal activities would have varying impacts to bull trout, depending upon which beneficial use was used for a particular dredging

activity. Proposed woody riparian habitat creation at Chief Timothy HMU in Lower Granite Reservoir (and possibly other sites on the

lower Snake River) would be unlikely to adversely affect bull trout. If in-water disposal to create fish habitat were selected as the

disposal option, impacts to bull trout would be similar to those for alternative 2. Although bull trout are very rare in the Snake River

and generally have only been reported during the spring and summer months, creation of shallow-water habitat could provide a

beneficial impact. If riparian habitat restoration were selected, bull trout may benefit. Fill activities on upland sites would have no

impact on bull trout. Potential impacts to bull trout would be considered prior to the selection of a beneficial use. The alternative

"may affect but is not likely to adversely affect" bull trout. This evaluation will be reevaluated as specific actions are selected.

4.3.1.3 Mitigation

Dredging would remove macroinvertebrate prey species within the dredging template. Recolonization would occur at the dredging

site during the next growing season. Alternative 2, to a lesser extent alternative 1, and potentially alternative 4 under the secondary

disposal management option, would reposition these materials to locations within the reservoirs that would allow for additional

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macroinvertebrate production. Prey availability would increase for juvenile out-migrating salmonids at the disposal locations.

Dredging to the natural river channel depth and in-water disposal can improve habitat conditions by providing habitat more

conducive to additional prey species production. In order to avoid direct impacts such as entrainment of juvenile salmonids,

dredging and disposal activities would occur when salmonid species are not likely to be present.

No mitigation is proposed since no impacts are anticipated.

4.3.2 Terrestrial Wildlife

4.3.2.1 Alternative 1 - No Action (No Change) -Maintenance Dredging With In-Water Disposal

Under this alternative, no trees would be removed; therefore, streamside and shoreline perch areas for bald eagle would not be

affected. Waterfowl, fish, and other prey would return to the dredged area very quickly after dredging. The dredging and disposal

activities would not be a continuous activity confined to a single location. If impacts were to occur, they would be minor, short-term,

and localized. Adjacent areas would be available for foraging, feeding, and perching.

This alternative "may affect but is not likely to adversely affect" bald eagles.

4.3.2.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

Impacts in the reservoirs would be similar to alternative 1.

Construction and operation of the Joso contingency upland disposal site would not affect habitat used by bald eagles. No suitable

perch trees would be removed and no habitat for prey species would be affected.

The levee raise would not result in the loss of any trees or shoreline perch areas. Prey species would not be impacted. Thus,

impacts if they were to occur would be related to disturbance during construction and would be minor, short-term, and localized.

This alternative "may affect but is not likely to adversely affect" bald eagles.

4.3.2.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

Dredging and disposal impacts would be similar to alternatives 1 and 2. The activity areas would be localized. Eagles could

continue to forage and feed in areas adjacent to the project. Upland disposal is anticipated to have a direct, long-term, minor impact

on eagles. These impacts are mainly attributable to increased activity at the Joso site. Bald eagles are seen very infrequently in this

section of the Snake River. Most eagle activity has been associated with migration through the area. None have been no ted to

winter on Lower Monumental reservoir except near the mouth of the Tucannon River.

This alternative "may effect but is not likely to adversely effect" bald eagles.

4.3.2.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

The dredging activity associated with this alternative would have the same impact as described for alternatives 1, 2, and 3.

Disposal activities would have varying impacts to bald eagles, depending upon which beneficial use was used for a particular

dredging activity. For woody riparian habitat restoration, prey species dependent upon riparian vegetation would benefit the most,

which may increase the food source for bald eagles. Establishment of shoreline vegetation and trees may provide additional perch

sites for bald eagles. Activities related to development of the shoreline habitat would potentially have short-term impacts on bald

eagles related to noise and construction activities. If in-water disposal to create fish habitat were selected as the disposal option,

impacts to bald eagles would be similar to those for alternative 2. The creation of shallow water using dredged material would result

in additional habitat for eagle prey species. This, in turn, would increase the availability of opportunity for feeding and, thus, would

be a beneficial impact for these birds. Fill activities on upland sites may have the potential to impact bald eagles if the activities

occur near the shoreline. Potential impacts to bald eagles would be considered prior to the selection of a beneficial use.

This alternative "may affect but is not likely to adversely affect" bald eagles. This determination would be reevaluated as specific

actions are selected.

4.3.2.5 Mitigation

Mitigation may be required for alternative 3. If perch trees are removed, artificial perches could be placed along the shoreline as

replacements. These could be located at the disposal site or at sites distant from the disposal activity.

4.3.3 Plants

4.3.3.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

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The dredging and disposal activities would be in habitats where water howellia (Howellia aquatilis) are not likely to exist. No impacts

are anticipated. Thus Alternative 1 "may affect, but is not likely to adversely affect" water howellia.

The dredging and disposal activities would not occur in habitats where Ute ladies’ tresses (Spiranthes diluvialis) exists (i.e.,

wetlands). Thus Alternative 1 "may affect, but is not likely to adversely affect" Ute ladies’ tresses. There would be no effect on

Spalding’s silene.

4.3.3.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

Impacts of dredging and disposal activities would be similar to alternative 1.

The construction and operation of the Joso upland disposal contingency site would have no impact on the listed plant species since

the plants do not occur at the site. Habitat for the three listed plant species does not occur in the vicinity of the levee raise. The

levee raise would have no impact on these species.

4.3.3.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

Water howellia do not occur in upland locations such as the Joso site or the area of the levee raise. No impacts would occur. There

would be "no effect" on water howellia.

No wetland impacts would occur with this option, therefore no impacts on Ute ladies’ tresses are expected to occur. Thus, there

would be "no effect" on Ute ladies’ tresses.

4.3.3.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

The dredging activity associated with this alternative would have the same impact as described for alternatives 1, 2, and 3.

Disposal activities would have varying impacts to listed plant species, depending upon which beneficial use was used for a

particular dredging activity. Placing dredged material in the river to provide new or additional shallow-water habitat, as described in

section 2.5.4, would not impact any plant species. For dredged material placement along the shoreline to create woody riparian

habitat, plant surveys may be required to determine the presence of Ute ladies’ tresses. Any sites found to support these plants

would need to be avoided to preclude impacts to these plants. Ute ladies’ tresses are not likely to occur downstream of Clarkston,

Washington, due to the prevalence of exotic plants within the existing wetlands. Since no formal surveys have been conducted for

this species on the lower Snake River, the shoreline will be surveyed prior to dredged material placement. If plants of this species

are found and would be impacted by the fill action, Consultation with USFWS would be reinitiated.

4.3.3.5 Mitigation

No impacts to endangered plants are anticipated. Mitigation is not deemed to be necessary unless plant surveys determine

endangered plant species are present.

4.4 RECREATION

4.4.1 Recreation Facilities, Activities, and Use Patterns

4.4.1.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Actions proposed as part of alternative 1 are expected to have a minor, short-term effect on those recreation activities and facilities

located near proposed dredging and disposal locations. Dredging scenarios proposed under alternative 1 may temporarily close

boat ramps and boat basins and affect public recreation areas (swimming beaches) on a short-term, temporary basis during

maintenance dredging. Effects would be minor due to low levels of activities that occur during the months for which dredging and

disposal are proposed.

4.4.1.2 Alternative 2 -Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

Actions proposed as part of alternative 2 are expected to have short-term, direct effects on recreational facilities and activities.

Dredging and disposal activities are expected to have effects similar to those discussed for alternative 1 above. Should dredging of

the boat basins and swimming beaches occur during the summer months, there would be a greater chance of disturbing

recreational use. However, the disturbance would be short-term and recreational use would resume once the dredging was

complete. The proposed construction of the levee raises within the Lewiston Levee Parkway under alternative 2 is anticipated to

have a short-term, direct effect on the recreational activities that occur at this park. These effects would be minor because they

impose a temporary disruption of activities at the Lewiston Levee Parkway; specifically, multi- use paths and day- use facilities such

as picnic tables on and adjacent to the levees could not be used during construction of the levee raise. Recreational facilities would

be restored and activities resumed following the interruption caused by the construction of the levee raise.

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Construction and operation of the Joso upland contingency disposal site would have no direct impact on recreation. The activities at

the disposal site may have an indirect impact on river users, hunters, and users of Lyon's Ferry State Park and Lyon's Ferry Marina.

Impacts would be sporadic, depending upon the need to use the disposal facilities and would be of short duration each time the

disposal site is used.

4.4.1.3 Alternative 3 -Maintenance Dredging With Upland Disposal

and a 3-Foot (0.9-m) Levee Raise

Dredging and levee modification activities proposed under alternative 3 would have the same effects on recreation as alternative 2.

Upland disposal activities at the Joso site would have long-term, indirect effects on river users, hunters, and the nearby Lyon’s Ferry

State Park and Lyon’s Ferry Marina facilities. These effects are anticipated to be minor since the disposal area is set back at least

600 feet (182.9 m) from the river shoreline and is not directly visible from Lyon’s Ferry State Park and Lyon’s Ferry Marina, which are

located on the opposite side of the Snake River.

4.4.1.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

Dredging and levee modification activities proposed under alternative 4 would have the same effects on recreation as alternatives 2

and 3. To the extent that beneficial uses of dredged material would reduce the need to dispose of the material either upland or in

water, these uses are expected to have minor, direct impacts to recreational facilities and activities, depending on where the material

is placed. Beneficial uses that would create or enhance wildlife habitat would have indirect beneficial effects on recreation if they

enhanced hunting, fishing, or wildlife viewing opportunities.

4.4.2 Mitigation

None of the alternatives considered are expected to have a significant impact on recreation facilities, activities, or use patterns.

Effects of maintenance dredging of recreational facilities in the winter would be minor due to low levels of activities that occur during

the winter months for which dredging and disposal are proposed, and would provide a long-term benefit for recreational boating. If

maintenance dredging of recreational facilities were performed during the summer months, the impacts on recreation would be

greater since recreational use is higher in the summer. However, this impact would still be minor since the dredging would require

closing the recreational facility for only a few days. The public would be notified of dredging operations and temporary boat

ramp/basin closures. Construction of the nominal 3-foot (0.9-m) levee raise in the Lewiston area is expected to directly affect

recreational facilities, activities, and uses associated with those levees. These effects can be lessened by creating detours for bike

and pedestrian users of these facilities, so they may remain usable while construction is taking place.

4.5 CULTURAL RESOURCES

Cultural properties located in the project area could potentially be affected by proposed dredging and disposal activities. This

section describes potential project effects on cultural properties. As with all proposed DMMP/EIS actions, Section 106 cultural

resources reviews under NHPA would occur dredging and dredged material disposal actions are developed.

During the NHPA evaluations, the Corps would consult with SHPOs of Washington, Idaho, and Oregon; Indian tribes; and other

interested parties to identify potential effects of the alternatives on cultural properties. Affected tribal and other local governments

would also be consulted during NEPA activities and implementation of Federal policies to the degree the governments are

interested.

4.5.1 Cultural Resources Effects

4.5.1.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Alternative 1 would continue the District’s current reservoir maintenance operations, which involves programmatic dredging to

maintain the navigation channel, access channels to ports and moorages, public recreation areas, and irrigation intakes for wildlife

HMUs. Disposing of dredged material at designated in-water disposal sites would continue.

To maintain reservoir navigation, dredging would be confined to existing navigation channels. Associated project activities are,

therefore, not expected to affect cultural properties. Dredging other identified project areas in some cases would occur over or very

near cultural properties. The depth of dredging would be indirectly controlled by hydrographic measurements taken before and after

dredging and by not removing material below the target elevation. In these few cases, cultural resources located in McNary, Ice

Harbor, Lower Monumental, and Little Goose reservoirs could be adversely affected. Proposed in-water disposal of dredged

materials could affect cultural properties located underwater in the lower Snake River and McNary reservoirs. This alternative could

have long-term effects on cultural properties associated with in-water disposal areas. Cultural properties could be affected by the

drift of dredged materials over time that cover known cultural properties with too much sediment load or that create an incompatible

chemical environment with existing site soils. Unknown cultural properties could be buried by in-water disposal actions. Monitoring

of cultural resources during dredging and disposal activities would be limited to standard inadvertent discovery procedures.

4.5.1.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

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Alternative 2 involves the same dredging scenario as alternative 1 and also includes a nominal 3-foot (0.9-m) levee raise in the

Lewiston area. Under alternative 2, disposal actions would be similar to those in alternative 1 except in- water disposal would be

limited to shallow-water and mid-depth disposal areas. Cultural properties are not expected to be affected by dredging, disposal, or

levee raise actions. The individual dredging projects would be subject to NHPA Section 106 reviews. There is the potential that

unknown cultural properties could be affected by burial with dredged materials. Cultural properties would need to be considered in

planning future DMMP/EIS actions within the area of potential effect of the proposed modification of the levee raise.

4.5.1.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

Alternative 3 involves the same dredging scenario and would have the same effects from dredging as alternatives 1 and 2. Cultural

properties identified at the Joso upland disposal site could potentia lly be affected by work site preparation and upland disposal

operations. Some of these sites are potentially eligible for the NRHP. However, proposed activities are expected to remain at a

considerable distance from any known cultural resources. There are no cultural properties associated with the existing pit at Joso

where dredged materials would be disposed under the DMMP/EIS. Access to the Joso disposal area would involve dredging to

provide barge access to an existing barge slip. This would require consideration for submerged cultural resources. Thus, the same

considerations for cultural properties would be followed as under alternative 2.

4.5.1.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

Dredging effects on cultural properties would be the same as those for alternative 2. In addition, beneficial uses for dredged

material other than for creating in-water fish habitat could potentially affect cultural properties depending on ho w and where the

use would be planned. The areas for the proposed woody riparian habitat creation under alternative 4 would be selected to avoid

impacts to known cultural resources sites. Prior to implementation of any beneficial use, the Corps would need to conduct research

and field investigation to determine if cultural resources would be potentially affected and would consult with the appropriate

SHPO's and other consulting parties.

4.5.2 Mitigation

The cultural properties that could be most affected by proposed activities involve those submerged beneath reservoir waters and

associated with in-water disposal areas. The Corps would, in consultation with SHPO's and other consulting parties, determine the

effect of in-water disposal on identified cultural properties. Access to most cultural properties in the study area for the purpose of

conducting NRHP evaluations is prohibitive since they lie beneath reservoir waters. The Corps is not aware of existing technology or

methods that would allow it to effectively address the matter of unidentified submerged cultural resources. Consequently, the Corps

would likely avoid known cultural properties in the study area as a practical approach in the planning of future in-water DDMP/EIS

actions. The Corps would apply contractual controls to dredging actions to provide accountability of dredging operations and

protection of cultural deposits.

Indirect effects resulting from disposal activities on nearby cultural properties would be assessed for each resource and disposal

action. This would be done until project effects could be reliably predicted and, if needed, alterations made in disposal practices to

avoid adverse effects to cultural properties. Submerged resources not NRHP eligible could be buried by the disposal of dredged

materials since this would not constitute an adverse effect under NHPA. However, given the unique qualities of study area cultural

properties, practicable efforts to avoid them would be taken when planning in- water disposal operations.

Steps similar to those described above would be taken to consider effects to cultural properties located on land whether on or off

Corps property in accordance with NHPA and the Reservoir Salvage Act, as amended. If necessary, cultural properties would be

evaluated to determine their NR eligibility status. The Corps would develop a detailed cultural resources monitoring plan if required

by consultation under Section 106 of the NHPA. Consultation will be completed prior to release of this document. The monitoring

plan would assure that project activities were assessed for their potential to affect cultural resources and provide avenues for

adaptive management within the DMMP/EIS. This plan would seek to integrate information from ongoing District-wide cultural

resources monitoring activities. If new cultural properties are found in the DMMP/EISs area of potential effect, this new information

would be considered and compliance with NHPA guidance would occur. In addition, a programmatic agreement may be developed

if SHPOs find this to be appropriate. Such a document would addresses how NHPA reviews would be applied for future DMMP/EIS

actions.

If human remains are inadvertently discovered during dredging or dredged material handling operations, all work in the immediate

area of the discovery would stop and would not resume until the matter regarding the discovery is satisfactorily resolved by the

Corps archaeologist. The Corps designated cultural resources specialists would be notified immediately of the discovery and the

Corps would notify appropriate tribes, law enforcement, and coroner’s offices. Every effort would be made to identify the cultural

identity of the remains and, if the remains are determined to be Native American, the Corps would comply with the terms set forth in

the Native American Graves Protection and Repatriation Act. The Corps would employ the same procedures if an archaeological site

is inadvertently discovered or impacted during dredging and/or dredged material management activities.

4.6 SOCIOECONOMICS

4.6.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Dredging to maintain the navigation channel, access channels to ports and moorages, public recreation areas, irrigation intakes for

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HMUs, and flow conveyance capacity of the Lower Granite reservoir, and disposal of dredged material in-water represent no change

in the management of the projects and associated facilities. Therefore, this alternative is anticipated to have no effects on regional

population, employment, or income. Since navigational clearances and water surface profiles would be maintained and no changes

in overall reservoir operations are proposed, this alternative is also expected to have little to no effect on river uses or users. Since

alternative 1 does not include a levee raise in Lewiston, allowing continued loss of levee freeboard and increased risk associated

with flooding, it could be expected (in comparison to the other alternatives being considered) to have an indirect, long-term,

moderate negative effect on the local economy of the Lewiston area.

4.6.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

Alternative 2 is expected to have the same socioeconomic effects as alternative 1 with respect to proposed dredging and disposal

activities. Proposed levee modifications are anticipated to have a direct, short-term, positive effect on the local economy of the

Lewiston area due to the added jobs and materials required for construction of the levee modifications.

4.6.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

Socioeconomic effects of the proposed dredging and levee modification activities for alternative 3 would be the same as those for

alternative 2. However, upland disposal would be expected to have a direct, short-term positive impact due to jobs created for

construction and initial operation of the disposal facility at the Joso site. The economic effects would remain positive, but lessen over

time, for the continued use of the upland disposal facility.

4.6.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

As with alternative 3, the dredging and levee modification components are anticipated to have the same socioeconomic effects as

those documented for alternative 2. Beneficial use of dredged material would be expected to have a direct, minor, short-term

positive economic effect due to construction activities associated with implementation of the beneficial use. Also, beneficial uses that

create or enhance wildlife habitat or recreational resources would potentially have minor, indirect, long-term beneficial effects

attributable to enhancement of recreational resources and opportunities.

4.6.5 Low-Income or Minority Populations

The proposed project alternatives would result in no disproportionately high and adverse impacts to the environmental justice

communities identified by project area census tract in section 3.6.3. The proposed dredging and dredged material disposal activities

would not directly affect any of the identified low-income or minority regions in the project area. Proposed mitigation and emphasis

on beneficial uses of dredged material would minimize adverse impacts that have been identified. Similarly the proposed levee raise

would not negatively impact any project area residences in a significant manner, but will provide added flood protection in the

Lewiston/Clarkston area. The proposed levee raises would not result in disproportionate flood hazard to the identified low-income

and minority communities.

The Tribes in the project area rely on the aquatic resources in the project area to a substantially greater degree than other

inhabitants of the project area, such that any significant negative impact to aquatic resources in the project area could

disproportionately impact the Tribes. Cultural resources in the project area are also sensitive for this same reason. However, the

alternatives documented in the DMMP do not result in any significant impacts to the aquatic or cultural resources which are

important to the Tribes. As described in Section 4 of the DMMP/EIS, no significant adverse impacts to water quality or aquatic

resources are anticipated to result from the DMMP alternatives. The National Marine Fisheries Service has concluded that the

proposed action could not be likely to jeopardize the continued survival of listed anadromous fish species in the project area. As

described in section 4.5, all known cultural resources could be avoided in the proposed alternative. As described in sections 4.14 and

4.15, the proposed alternatives could result in either no effect to fish and fishing, or in a net positive effect. The preferred alternatives

recommended plan was determined to not have a negative disproportionate impact on tribal communities.

None of the proposed alternatives are expected to have negative impacts to agricultural pursuits in the project area. As such, all

project alternatives are expected to result in no negative disproportionate impacts to Hispanic farm workers in the project area.

4.6.6 Mitigation

None of the plan alternatives are expected to have adverse socioeconomic effects. Mitigation measures are proposed to avoid and/or

minimize environmental impacts. Proposed mitigation measures that would address anticipated environmental impacts are

described in Section 4 within the context of the resources impacted.

4.7 TRANSPORTATION

4.7.1 River Navigation

4.7.1.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

This alternative would have a long-term beneficial impact on river navigation by ensuring adequate depths in the navigation

channels, and access channels to ports, moorages, and public recreation areas. Dredging would be completed in the navigation

channels in each of the reservoirs to provide depths up to 14 feet (4.3 m), plus another 2 feet (0.6 m) for advanced measures and

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overdig. Materials would be disposed of in each reservoir in shallow-, mid-depth-, and deep-water areas away from areas of

commercial and recreational river navigation. Dredging in the navigation channels could occur as frequently as a 2-year cycle,

causing some disruption in the in-water work period from December 15 to March 1 in the Snake River and December 1 and March

31 in the Columbia River. Dredging in the access channels to ports and moorages would occur on an as- needed basis. Disruption

would be minimized through notification to mariners and processes that avoid blocking busy waterway segments for periods longer

than 1 or 2 days. Barges used to transport dredged material would traverse only the reservoir where the material was dredged and

would not impact lock utilization. No disruption to recreational boating would be expected in the main river channels; only short-term

disruption may occur during maintenance dredging of boat basins.

4.7.1.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

This alternative would have similar impacts to river navigation as alternative 1. There could be increased barge traffic through some

of the navigation locks if material dredged from the downstream reservoirs is barged to Lower Granite reservoir for in- water

disposal. Additionally, the transport of any dredged material to the Joso site would require use of the locks, except for Lower

Monumental where Joso is located. No measurable impacts to river navigation through the locks are expected as a result of this

material.

4.7.1.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

This alternative would have the same impacts as alternatives 1 and 2 with the addition of impacts to utilization of the locks. Dredged

material from each of the reservoirs would be deposited at the Joso site located in the Lower Monumental reservoir. Barges carrying

dredged material could increase the number of lockages during the dredging period by as much as 150 lockages as frequently as

every 2 years (up to 113 barges with an average of 4 lockages of 3 barge tows). These lockages would occur during a time of year

when they would cause very little impact to other commercial or recreational traffic.

4.7.1.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

This alternative would have impacts similar to all others in the dredging area. It could have different effects in the disposal area

depending on the disposal location and method employed to develop the beneficial use. In every case considered, the adverse

impacts to other river navigation would be short-term and minor. In some cases beneficial uses could have positive impacts to river

navigation by using the dredged material as fill to improve terminal and port areas.

4.7.2 Railroads

4.7.2.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Continued maintenance of the navigation channels, access cha nnels to ports and moorages, public recreation areas, irrigation

intakes, and flow conveyance capacity would have no adverse effect on the railroads in the area and would continue to support the

multi- modal flow of commerce to and from the study area.

4.7.2.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

This alternative would have the same affect on railroads in the area as alternative 1, with minor, short-term impacts resulting from

construction of the 3-foot (0.9-m) levee raise and use of the Joso disposal site. The nominal 3-foot (0.9-m) levee raise includes

construction of a bin wall to the west levee below the south abutment of the CPRR Bridge over the Clearwater River at Lewiston.

Construction of the bin wall could cause minor disruption to rail operations for a short period due to construction adjacent to bridge

abutments. This would not have a noticeable effect on rail operations. The Joso site, located on the south bank of the Snake River

between RM's 56.5 and 58.6, would be used by an estimated two to three barge loads per year. The UPRR runs along the south

boundary of the site and land access to Joso crosses the railroad’s right-of-way. While the development of this site and future

disposal operations would be conducted from the water over barge access facilities, minor increases in crossings of the UPRR rightof-way during construction could be expected. These impacts would be minimized through appropriate early communication and

coordination with the UPRR.

4.7.2.3 Alternative 3 -Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

This alternative would have the same impacts as alternative 2 plus minor, long-term, direct impacts to the UPRR resulting from

development of the Joso disposal site, located on the south bank of the Snake River between RM's 56.5 and 56.8. As with

alternative 2, land access to this site crosses the UPRR right-of-way. While the development of this site and future disposal

operations would be conducted from the water over barge access facilities, minor increases in crossings of the UPRR right-of-way

during construction could be expected. These impacts would be minimized through appropriate early communication and

coordination with the UPRR.

4.7.2.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material

and a 3-Foot (0.9-m) Levee Raise

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The potential impacts to railroads from this alternative are expected to be minor. The beneficial use of the dredged material would

be determined on a case-by-case basis and may affect the railroads due to minor disruptions of the type described under

alternatives 2 and 3, or could potentially involve the railroad to transport dredged material to a final destinatio n point. When

beneficial use options that could impact the railroads are considered for implementation, the appropriate railroad officials would be

involved early in the planning phase.

4.7.3 Highways/Roadways

4.7.3.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

This alternative would have no effect on the highways/roadways in the area. No direct effects to roadways are anticipated. River

navigation would be maintained and would contribute to commercial truck transportation serving port and river terminal facilities.

4.7.3.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

This alternative would have the same impact as alternative 1, with the added short-term, direct impacts to Highway 129 and the

Snake River Road resulting from the construction of the nominal 3-foot (0.9-m) levee raise. Highway 129 between Asotin and

Clarkston would be raised 3 feet (0.9 m) for approximately 1 mile (1.6 km). The Snake River Road above Asotin would be raised 1

foot (0.3 m) for a length of approximately 0.2 mile (0.3 km). Appropriate traffic control during construction and use of detours would

mitigate the impacts to traffic over these roadways.

4.7.3.3 Alternative No. 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

This alternative would have the same impacts as alternative 2. Upland disposal would have no additional effect on any roadways

since all material would be transported to the Joso upland disposal site by barge.

4.7.3.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

This alternative would have the same effect as alternative 2 and may potentially have a beneficial effect. One concept for beneficial

use of dredged material would use the material to form a roadway connection on the north shore of the Lower Granite reservoir

linking SR 193 at Wawawai to SR 194, a distance of 3 miles (4.8 km). This new section of roadway would eliminate the need to use

an existing 32- mile (51.5-km) stretch of narrow, steep road.

4.7.4 Mitigation

Overall, effects of any of the alternatives considered are expected to be minor. Mitigation of impacts to transportation from each of

the alternatives would include establishing road detour routes during construction of the proposed 3-foot (0.9-m) levee raise and

appropriate notification and coordination with the UPRR, which could be affected by upland disposal options. Where activities under

each of these alternatives may impact existing transportation, actions would be taken to notify and coordinate with affected parties in

advance of any of the temporary disruptions.

4.8 GEOLOGY AND SOILS

4.8.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

This alternative involves dredging to maintain the authorized depths in the navigation channels of the lower Snake River and McNary

navigation projects, maintenance dredging of access channels to port and moorages, public recreation areas, irrigation intakes for

wildlife HMUs, and flow conveyance capacity of the Lower Granite reservoir. This alternative would ensure navigation clearance and

provide some restoration of the flow conveyance capacity with maintenance dredging, but does not involve modifications to the

levees in Lewiston. Disposal of dredged material would be in-water at selected sites in each reservoir.

This alternative is not anticipated to significantly affect the geology and soils in areas surrounding the lower Snake River and

McNary reservoirs. Dredging would cause local soil and rock disturbance and relocation of some alluvial material.

4.8.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

This alternative considers the same dredging activities as alternative 1 with a nominal 3-foot (0.9-m) raise to the Lewiston levees.

Dredging would improve the navigation clearances in each reservoir and a 3-foot (0.9-m) levee raise at critical locations would

restore the flow conveyance capacity of the upper reach of Lower Granite reservoir.

The proposed dredging is not expected to affect the geology and soils in the study area. However, modifications to the levee system

in Lewiston are expected to result in direct effects on the geology and soils of the levees and surrounding areas.

The existing levees were modeled for stability using the UTEXAS3 slope stability model. The steady seepage condition for the

landside slope was analyzed. A high safety factor was computed for the levees based on past experience with levee stability and

seepage issues.

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Minor, short-term effects to soils and topography, resulting from earthmoving and construction activities, are expected during

construction of the levee modifications. However, the proposed levee modifications are not expected to have long-term effects on the

geology or soils of the surrounding areas. The use of construction best management practices (BMP's) would reduce the erosion

that could occur as a result of the levee modifications.

4.8.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

This alternative considers the same dredging activities as alternatives 1 and 2, with upland disposal of dredged material instead of

in- water disposal. The 3-foot (0.9-m) levee raise described as part of alternative 2 would be included with this alternative. In this

alternative, dredged materials from all reservoirs would be transported by barge to the Joso upland disposal site, located on the

Snake River between RMs 56.5 and 56.8.

Other than at the Joso site, no significant changes in the geology and soils of the surrounding areas are expected.

Upland disposal is anticipated to have a direct, long-term effect on the soils and topography of the Joso site. Erosion and

compaction would occur from construction and dredged material disposal activities. Runoff and erosion would be mitigated during

disposal by use of BMPs. Disposal materials would be placed on the Joso site in increments to maximize site restoration and

minimize the land used. Site restoration would include stabilizing and seeding of the dredged material after it has been disposed of

onsite. Disposal material would be contained within a bermed area and drainage would be controlled to minimize erosion. In

addition, a 600-foot (182.9-m) setback from the river would help minimize shoreline erosion.

4.8.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

Alternative 4 involves the same dredging and levee modification components as alternatives 2 and 3 above, but would use some or

all of the dredged material for beneficial uses. Beneficial uses, such as woody riparian habitat creation, other habitat

creation/enhancement, landfill cover, or other activities, would be expected to have direct, short-term impacts to the soils in the

areas where the uses would be implemented. Impacts could be mitigated by use of BMPs to control erosion and by minimizing the

areas that would be disturbed by the placement of dredged material.

4.8.5 Mitigation

Construction BMPs to reduce soil erosion are recommended for alternatives 2, 3, and 4, which involve modification of levees in the

Lewiston area. Use of BMPs in the construction and operation of the dredged material disposal facility at the Joso site, proposed

under alternative 3, is recommended to reduce soil erosion. Phased development and filling of the disposal facility, site restoration,

and creating a 600- foot (182.9- m) buffer between the disposal facility and the shoreline are also recommended for alternative 3 as

measures to reduce impacts to soils.

4.9 WATER QUALITY/WATER RESOURCES

4.9.1 Water Quality

4.9.1.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Under alternative 1, all dredging would continue to be performed during the winter in-water work window using mechanical methods

only. The proposed dredging and dredged material disposal is expected to have a temporary, direct negative effect on water quality

in the Columbia, Snake, and Clearwater Rivers. The effects would primarily be associated with turbidity plumes caused by the

dredging and in-water disposal, re-suspension of materials, and ammonia. Dredging the navigation channels, access channels to

ports and moorages, public recreation areas, and irrigation intakes would have little measurable effect on long-term water quality.

In-water disposal of this material is also expected to have a minor, short-term impact, and may cause temporary turbidity plumes.

As noted in Section 3.9, since there are no uniform freshwater sediment quality criteria that provide definitive numerical standards for

evaluation of dredged material, the Corps is developing a Mid-Columbia and Lower Snake Region Sediment Testing Framework.

Until the Mid-Columbia and Lower Snake River Framework is completed, the Dredged Material Evaluation Framework: Lower

Columbia River Management Area will be used by the Corps to evaluate the potential effects of dredging and dredged material

management activities.

4.9.1.1.1 Impacts of Dredging

Salinity

Dredging may cause an increase in salinity because re-suspension of sediments can put more of the major ion and cation salts into

solution. Freshwater biota that are not used to sudden changes in dissolved salt concentration could be negatively impacted by

such changes because they lack the capacity to osmoregulate in even a small increase of salinity.

Turbidity

The proposed dredging in areas close to the streambank, in port areas and boat basins, at the Snake/Clearwater Rivers confluence

area in Lower Granite reservoir, and backwater areas of McNary reservoir are expected to have the most impact on turbidity since

the sediments in these areas are expected to be fine-grained material. The Corps anticipates that dredging operations may create a

detectable plume extending about 1,000 feet (304.8 m) downstream. Best management practices would be used to prevent a 5-NTU

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increase over background (or a 10 percent increase over background when background is over 50 NTUs at a point more than 300

feet (91.4) downstream. Small or short duration turbidity exceeding water quality protection objectives would trigger the Corps to

scale back dredging operations until the turbidity management goals are obtained. Gross turbidity exceeding limits that would

generally be considered harmful to aquatic life would not be permitted. Should turbidity levels continue to be exceeded, the Corps

would stop the dredging and review the excavation methods and practical turbidity management measures before allowing the

dredging to continue. It is anticipated that small episodic turbidity plumes would dissipate when dredging ceases for the day or

when the dredge is moved to a new location.

Dredging the main navigation channel and the navigation lock approaches is not expected to create a significant turbidity plume.

This is because the sediment in the navigation channel is predominantly sand and the materia l in the navigation channels is

predominantly river cobble with some large rocks. Neither of these materials contains large quantities of fine materials.

Dissolved Oxygen

The proposed dredging activities under this alternative are expected to have a negligible effect on dissolved oxygen concentration

because all dredging would occur during cold-weather months. Dissolved oxygen concentration is higher at lower water temperature

for several physical reasons including the solubility of oxygen in the gaseous phase and pressure effects on the solubility of the

partial pressures of gases. Data collected during previous winter dredging activities indicated there was little change in dissolved

oxygen. Dissolved oxygen readings were at less than saturation only when there was very high background turbidity.

Temperature

The potential for dredging under this alternative to affect water temperature is negligible. All dredging would be performed in the

winter when both water temperature and air temperature are low. The overall effect on reservoir temperature would be

immeasurable.

pH

Dredging activities may affect pH levels in the work area and in the turbidity plume that would extend downstream of the work area.

Water quality data collected in the last 5 years indicates the Snake River is alkaline most of the year. Average pH for all months

ranges from 7.9 to 8.6 with average winter measurements ranging from 8.0 to 8.5. This is within the range of pH (6.5 to 8.5)

identified by the State of Washington as having very little direct effect on the aquatic environment. However, the proposed dredging

may lower or raise pH levels in the water. If the material being dredged contains a large amount of organic material and acids, the

pH in the work area may be lowered. This may occur in the boat basins and some port areas where there is a large amount of silt

and organics. If the dredged material contains carbonate compounds, the pH in the work area may be raised. This may occur in

parts of the navigation channel although it is not likely since the material in the channel is mostly sand, which contains mostly silica,

not carbonate. Should the pH be lowered to below 6.0 or raised to 9.0 or above, it could create lethal conditions for fish. The Corps

does not have data on how previous dredging activities affected pH in the water. The Corps proposes to monitor pH during the next

few dredging activities to determine if there is an effect on pH and to determine if the Corps needs to make changes in its dredging

procedures.

Dredging activities in the Columbia and Clearwater Rivers would be expected to have impacts to pH similar to those in the Snake

River.

Chemicals of Concern

Dredging activities have the potential to affect concentrations of compounds in study area reservoirs, primarily from dredging and

movement of sediments that may have some level of contamination. Fine sediment is the only dredged material that is potentially

contaminated. Sands and cobbles are not expected to contain contaminants. However, review of the Corps’ sediment sampling data

indicates little if any contamination exists in fine river sediments in the areas proposed to be dredged. There is a low risk of changes

to water quality because of release of chemicals of concern from the sediments.

Additional sampling for chemicals of concern is recommended prior to dredging to verify the conditions have not significantly

changed. Sediments will be evaluated in accordance with the adopted Dredged Material Evaluation Framework. Sediments with

ambient elutriate test levels above water quality criteria should be addressed prior to the beginning of the dredging activity to

determine if the concentrations in the sediment plume would violate water quality criteria.

As described in section 3.9.2.6, any radioactive material (if present) within McNary reservoir would most likely have been introduced in

the 1940's, 1950's, or early 1960's. In that case, it should be buried under sediments that have accumulated since that time.

Because Corps dredging operations would not extend down into original riverbed material or would go no deeper than post-1970

dredging activities in the same area, any buried radioactive material should remain undisturbed. Although the possibility of

disturbing radioactive material during a dredging operation is small, the Corps plans to evaluate each dredging activity in the

McNary reservoir for this potential and determine if and what type of further pre-dredging sediment testing and analysis may be

necessary.

Phosphorus

Dredging may result in small releases of phosphorus, but this should not pose a problem to water quality or the aquatic

environment. Because the dredging would occur during the winter in-water work window when cooler temperatures and reduced

photoperiod decrease plant growth, the release of phosphorus should not lead to excessive blooms of aquatic flora in any of the

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reservoirs.

Ammonia

Dredging in the Snake River reservoirs has the potential to raise ammonia levels in the water column since ammonia is present in

some of the sediments that would be dredged. Actual ammonia contamination levels that would be released into the water are site

specific, dependant upon temperature and pH of the water, and vary considerably due to particle size of the material being

dredged. Finer-grained sediment (i.e., silt) would be expected to have higher ammonia concentrations and would be more likely to

release larger amounts of ammonia (both ionized and un- ionized) into the water. The amount of ammonia that would be released is

unknown. The amount of un- ionized ammonia, which can have toxic effects on aquatic organisms, is also unknown. The Corps

would monitor ammonia levels in the water during dredging. If the levels reached critical concentrations (see the critical

concentration levels presented in appendix H, Water and Sediment Quality), the Corps would modify its dredging operation to try to

lower the ammonia levels in the water.

Dredging in McNary reservoir may have a similar potential to raise ammonia levels in the water column. Dredging silt- laden

sediments in the reservoir may have similar impacts as dredging silt in the Snake River reservoirs. The Corps would also monitor for

ammonia when dredging in McNary reservoir.

4.9.1.1.2 Impacts of Disposal

Salinity

The re-suspension of sediments during disposal operations is expected to have effects similar to those of the dredging operations.

Turbidity

The discharge of the dredged material in-water is expected to cause definable turbidity plumes. The plumes are expected to be of

short duration since the discharge from a bottom-dump barge is a singular event as opposed to the continuous operation of the

dredge. Previous discharges of such materials suggest the material tends to stay in a clump as it drops from the barge to the

riverbed, further minimizing the size of the plume. The plumes at the shallow to mid-depth habitat in-water disposal sites are

expected to be smaller since the material to be disposed of in these areas would be primarily composed of sands. The plumes at

the deep-water sites are expected to be larger since the material to be disposed of in these sites would be primarily silt. The turbidity

plume is expected to visible as much as 1,000 feet (304.8 m) downstream. Based on monitoring data from previous dredging and

disposal activities, turbidity would not be expected to exceed state water quality standards.

Dissolved Oxygen

The proposed winter disposal activities under this alternative are expected to have a negligible effect on dissolved oxygen

concentration because all dredging would occur during cold-weather months. The water is colder during the winter and has higher

dissolved oxygen levels than in the warmer months when the water is warmer. There is also less biological demand for oxygen in

the winter. Even though some of the sediments being disposed of would contain organic material, the demand for oxygen for

decomposition of those materials would not cause a noticeable decrease in dissolved oxygen.

Temperature

The potential for the in-water disposal action under this alternative to affect water temperature is negligible. All dredging would be

performed in the winter when both water temperature and air temperature are low. The overall effect on reservoir temperature would

be immeasurable. After the shallow-water or mid-depth habitat is created, a localized temperature increase would be expected. This

is because the river bottom would be raised to the photic zone, allowing the substrate to absorb more radiant energy and, thereby,

warm the water. This warming would have a negligible effect on the water temperature of the entire reservoir.

pH

The impacts of disposal on pH of the affected river water are assumed to be similar to those of dredging.

Chemicals of Concern

The impacts of disposal regarding chemicals of concern may be similar to those of dredging. A review of sediment and water quality

data has indicated that levels of contamination in sediments would probably not preclude the disposal in-water in the winter. Based

on analysis of sediment samples taken from the Columbia, Clearwater, and Snake Rivers, there may be a portion of the sediments

containing contaminants in concentrations that may preclude in-water disposal. The location of the contaminated sediments (if there

are any) would be identified prior to the dredging action. Those sediments would be disposed of in an appropriate upland location.

Phosphorous

The impacts of disposal on phosphorous in the river environment would be similar to those of dredging.

Ammonia

The impacts of disposal on ammonia (both ionized and un-ionized) in the river environment would be similar to those of dredging

except that the severity would likely be less for the disposal operation. When the barge dumps the dredged material during in- water

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disposal, it should fall through the water column in a mass with significant exchange limited to the material around the outer edges

of the mass. This would result in less of the sediment being exposed to the surrounding water than during the dredging operation.

4.9.1.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

Under alternative 2, most dredging would be performed during the winter in-water work window using mechanical methods;

however, this alternative also includes the possibility of using hydraulic dredging for irrigation intakes and using summer dredging

for off-channel sites such as irrigation intakes, boat basins, and swimming beaches on a case-by-case basis. The proposed

dredging is expected to have a temporary, direct negative effect on water, mostly because of turbidity plumes caused by the

dredging and in-water disposal. Dredging the navigation channels, access channels to ports and moorages, public recreation areas,

and irrigation intakes should have little effect on long-term water quality.

4.9.1.2.1 Impacts of Dredging

Dredging impacts would vary depending on the time of year when dredging takes place and the method of dredging. For

mechanical dredging in the winter, the impacts on water quality parameters are expected to be the same as the impacts discussed

under alternative 1 (section 4.9.1.1). Hydraulic dredging, regardless of time of year, would be expected to have little impact on water

quality since the dredged material would be captured by suction with little interaction with the water column. Summer dredging

would be confined to off-channel areas and could impact the water quality parameters of dissolved oxygen and ammonia differently

than winter dredging in those areas. Summer dredging in the small and confined areas would have little overall water quality

impacts to the reservoirs depending upon the duration of the dredging and the integrity of any barriers (e.g., silt curtains) used to

keep turbidit y and potential contaminants within the off-channel area. Any flow of contaminated water into the main river channel

would be miniscule compared to the amount of flow in the river. Because the water would be warm, the dissolved oxygen levels

would be lower than in the winter when the water is colder. Resuspension of organic material in the silt may increase the demand

for oxygen for decomposition and further reduce the amount of dissolved oxygen in the water. In the immediate area of the dredging

operation, high, localized water quality degradation is expected to occur with high concentration of un- ionized ammonia possibly

exceeding the acute level of contamination for many species of aquatic life. As described in alternative 1, the Corps would monitor

the amount of ammonia released into the water column during dredging and adjust the dredging operation if necessary to reduce

the amount of ammonia being released.

4.9.1.2.2 Impacts of Disposal

For dredged material disposal in the winter, the impacts on water quality parameters are expected to be similar to the impacts

outlined under alternative 1 (section 4.9.1.1). If the material were suitable, the focus would be creating shallow-water fish habitat. The

impacts of this placement would be similar to those described for the mid- and shallow-water disposal in alternative 1.

Any hydraulic dredging at irrigation intakes would pump slurry onto the land and would have minimal impacts to water quality. The

water in the slurry would be expected to percolate into the soil or evaporate.

Disposal of dredged material from summer dredging would have little or no impact to water quality. This is because all material

dredged in summer would be disposed of at an upland location. The material would be placed in a location where the water would

percolate into the soil or evaporate, or the material would be placed within a holding area and the effluent would be allowed to

re-enter the river. The effluent would be monitored before it is discharged back into the river.

Joso Contingency Site

When developed sometime in the future, the Joso contingency site would be used for disposal of silt in excess of that allowable for

building the base of shallow-water habitat areas, for disposal of some or all of the material dredged in the summer, and for disposal

of moderately contaminated material unsuitable for in-water disposal. In-water work for the construction of the Joso site would be

expected to have similar impacts to water quality as dredging in any other backwater, as mentioned under alternative 1.

The disposal facility at the Joso site would be set back approximately 600 feet (182.8 m) from the Snake River, minimizing potential

water quality impacts from construction and operation of the facility. Direct, temporary, minor impacts due to erosion may occur as a

result of construction and disposal operations. A containment berm would be constructed on the perimeter of the permanent

disposal area and would minimize water quality impacts associated with runoff and erosion. Most impacts are expected to be

minimal and to occur in a localized area. The process of removing silt and placing it upland would eliminate any impacts associated

with in- water disposal, however minor.

Levee Construction

Construction of the levees at Lewiston could result in short-term, minor water quality impacts due to runoff and erosion. These

concerns would be minimized with the implementation of a site-specific Erosion/Sedimentation Control (ESC) Plan and BMPs. The

levees would be stabilized by hydroseeding immediately after construction. All construction activities associated with this project are

subject to the phase 2 stormwater runoff rules. Catchments, flow prevention, BMPs and monitoring would be used. Permits to

discharge stormwater runoff would be required from the contractor.

4.9.1.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

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This alternative is expected to have the same dredging, levee construction, and Joso Contingency Site construction impacts as

described in alternative 2; however, all disposal of material would occur upland at the Joso site. Impacts would be similar for upland

disposal but there would be no impacts occurring from in-water disposal.

4.9.1.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

This alternative would have the same impacts for dredging and levee construction as described for alternative 2. Impacts due to

beneficial use of the dredged material could vary depending on the use and would be the responsibility of either the Corps or the

local sponsor (if there is one). In-water disposal for fish habitat and upland disposal at the Joso site would have the same impacts

as alternative 2.

4.9.1.5 Mitigation

As described above, water quality impacts would be short-term in nature and would be mitigated by any or all of the following

methods:

Monitoring during dredging/disposal activities, as described in section 4.9.1.1, appendix J - Dredged Material Evaluation

Framework, and appendix M – Monitoring Program. If monitored water quality parameters are exceeded, dredging would be

suspended and/or altered until the exceeded parameters return to acceptable levels.

Implementing site-specific ESC and BMPs.

Stabilizing material placed at the Joso site by hydroseeding or other appropriate methods.

Hydroseeding/restoring levees immediately after construction.

4.9.2 Wetlands

4.9.2.1 Alternative 1 - No Action (No Change) – Maintenance Dredging With In-Water Disposal

This alternative would continue maintenance dredging with in- water disposal. There are no foreseeable wetland impacts as a result

of alternative 1.

4.9.2.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

Alternative 2 would dispose of dredged material in- water, raise some existing levees 3 feet (0.9-m), and include roadway raises

associated with levee modifications. The levees or roadway improvements, as currently proposed, would not substantially increase

the footprints of either the levee or the roadway, or encroach on undeveloped land. Minor, short-term, indirect impacts to wetlands

adjacent to the levees or roadway could occur during construction of these improvements. Long-term impacts are not expected as a

result of the levee raise. Dredged material unsuitable for in-water disposal would be disposed of at the Joso site. Impacts would be

similar to those described in Alternative 3 for upland disposal of all dredged material.

No wetland impacts are expected to result from in-water disposal of dredged material.

4.9.2.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

This alternative would raise the levees and roadways as in Alternative 2, but would dispose of dredged material upland at the Joso

site. The levee and roadway modifications, as proposed, would not substantially increase the footprints of either the levee or the

roadway, or encroach on undeveloped land. Minor, short-term, indirect impacts to wetlands adjacent to the levees or roadway could

occur during construction of these improvements. Long-term impacts are not expected as a result of the levee raise.

The proposed Joso upland disposal site, as designed, is anticipated to have a minor, indirect impact on the two southwestern

wetland parcels. The impacts would result from the unloading of dredged material that would occur approximately 400 feet (121.9

m) to the north of the wetlands. The barge unloading and sediment movement may disrupt wetland function through wildlife

displacement and sediment movement. There is expected to be no impact to the third wetland parcel to the northeast of the Joso

site.

4.9.2.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

Beneficial uses would be expected to generally affect wetland resources positively if dredged material were used for enhancement

or creation of aquatic and wildlife habitat. Beneficial uses could potentially improve wetland size, function, and quality. Specific

wetlands in the vicinity of a proposed beneficial use would require identification prior to commitment for the beneficial use project. A

wetland area approximately one acre (0.4 hectare) in area is adjacent to the area at Chief Timothy HMU where woody riparian

habitat development is proposed in winter 2002-2003. This wetland area would be minimally impacted by the proposed habitat

development. The wetland is a low area where ponding occurs; it holds water only at extremely high pool elevations, and dries out

during most years. Under the proposed beneficial use, an inlet channel to the pond would be constructed, which should increase

flows into the pond at lower reservoir elevations. It will also have an exit (outlet) constructed so there will be some flow through, thus

improving the water quality.

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4.9.2.5 Mitigation

Potential mitigation measures for road and levee improvements, if needed, include minimizing impacts during construction by

avoidance and adherence to any local or state erosion control policies. The Corps would conduct a wetland delineation as part of

the planning process. Refinement of designs would seek to avoid and minimize wetland impacts to the extent practicable. Any

wetland parcels that may be filled during construction would be mitigated in accordance with regulatory authorities.

Erosion control and avoidance of wetlands are planned at the Joso site.

4.9.3 Floodplains

4.9.3.1 Alternative 1 - No Action (No Change) – Maintenance Dredging With In-Water Disposal

This alternative would continue maintenance dredging with in- water disposal. A change in water surface elevation at the in-water

disposal sites is not anticipated. As a result, there are no foreseeable floodplain impacts as a result of alternative 1.

4.9.3.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

Alternative 2 would dispose of dredged material in- water, raise some existing levees 3 feet (0.9 m), and include limited roadway

modifications. The levees or roadway improvements, as currently designed, are not expected to encroach on undeveloped land and,

therefore, would not impact the 100-year floodplain.

The Joso site has been identified as a site for upland disposal for unsuitable material, if needed. This site would potentially be used

under alternatives 2, 3, and 4. The proposed containment and disposal facility is not located in the 100-year floodplain. There would

be no long-term impact to the floodplain. Based on the conceptual site layout, approximately 11,000 square feet [1 021.9 square

meters (m2)] of the temporary storage area would encroach on the 100-year floodplain. This would present minor short-term impacts

to the floodplain since this use would be temporary and the fill is not expected to change the water surface elevation.

A significant change in water surface elevation at the in- water disposal sites is not anticipated. As a result, there are no foreseeable

floodplain impacts as a result of the in- water disposal portion of Alternative 2.

4.9.3.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

This alternative would raise the levees and roadways as in alternative 2, but dispose of dredged material upland at the Joso site.

The levee and roadway modifications, as currently designed, would not substantially increase the footprints of either the levee or the

roadway, or encroach on any undeveloped land. The permanent upland disposal site at Joso would not be located in the 100-year

floodplain and would not affect the floodplain. Approximately 360,000 square feet (33 445.1 m2) of the temporary storage area for

dredged material would encroach on the 100-year floodplain. There would be minor short-term impacts to the floodplain during the

time that the material is stored. However, the fill is not expected to change the water surface elevation and would not pose long-term

effects on the 100-year floodplain.

4.9.3.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

Beneficial uses considered by the Corps are not anticipated to present significant impacts to floodplain areas. The proposed woody

riparian habitat creation would involve placement of fill in shoreline areas, which may include some areas within the 100-year

floodplain. This fill would not change the water surface elevation, nor have impact on the 100-year floodplain. Specific areas

considered for placement of dredged material under beneficial use would require analysis of floodplain issues.

4.9.3.5 Mitigation

Anticipated effects to floodplains are expected to be minor and temporary. Therefore, no mitigation of floodplain impacts is

proposed.

4.10 HAZARDOUS, TOXIC, AND RADIOACTIVE WASTE

Potential land-based HTRW concerns associated with upland disposal sites considered in this DMMP/EIS are discussed in this

section. Findings and evaluations of potential environmental effects are based upon Phase I Environmental Site Assessments

conducted for the Joso site. The handling and disposal of dredged materials as hazardous is not anticipated to be required.

Potential HTRW concerns associated with the sediments to be dredged are discussed in section 4.9.1.

4.10.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

There are no HTRW impacts since this alternative does not involve upland disposal.

4.10.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

The proposed disposal of dredged material that may be unsuitable for in-water disposal at the Joso site would not have significant

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effects related to management of HTRW. The findings of the Phase I Environmental Site Assessment of the Joso site indicated the

presence of limited and localized tire burning and asphalt dumping activities on the site. These findings do not indicate HTRW

concerns that would require further site investigation. Unsuitable (contaminated) dredged materials would be isolated and

appropriate confinement measures taken (e.g., an impervious liner installed to prevent leaching). Disposal of dredged material at

the Joso site is anticipated to have no effect regarding management of HTRW.

4.10.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

The proposed disposal of dredged material at the Joso site would not have significant effects related to management of HTRW as

described in alternative 2. Disposal of dredged material at the Joso site is anticipated to have no effect regarding management of

HTRW.

4.10.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

The proposed woody riparian habitat creation area at Chief Timothy HMU does not pose any known HTRW concerns. Beneficial use

of dredged materials could have minor positive effects on HTRW if dredged material were used for cover or fill at the Hanford

Reservation. In general, beneficial uses that involve upland handling of dredged materials would not be expected to have HTRW

effects, given the quality of the sediments. Site assessment of proposed disposal/use areas would be necessary to confirm no

HTRW concerns are associated with the area.

4.10.5 Mitigation

If alternative 3 were selected as the preferred alternative, prior to development of an upland dredged material disposal facility at

Joso, the tire remnants and asphalt that were found during site reconnaissance should be removed and disposed of off- site in

accordance with Federal, state, and local solid waste regulations.

4.11 AIR QUALITY

4.11.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Under this alternative, mechanical dredging and in-water disposal would be continued to maintain the navigation channels of the

lower Snake River reservoirs and McNary reservoir, access channels to port and moorages on an as-needed basis, public recreation

areas (swimming beaches and boat basins), irrigation intakes for wildlife HMUs, and flow conveyance capacity of the Lower Granite

reservoir. No modification would be made to the levees that protect Lewiston, Idaho, and Clarkston and Asotin, Washington.

Dredging, transport, and in-water disposal activities typically do not generate fugitive dust or minor diesel fuel emissions. No air

quality impacts are anticipated within the study area.

4.11.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

As described under alternative 1, dredged material disposed of in-water would be wet and not subject to wind entrainment.

Construction activities associated with raising the west Lewiston levee could generate dust. As discussed in section 3.11, fugitive dust

control requirements are in the IDAPA 58.01.01, Section 650 through 651, and reasonable precautions would be taken to prevent

the generation of fugitive dust. Reasonable precautions that would be most applicable would include, but are not limited to, the

following:

Use of water or chemicals to abate airborne particles (dust) during construction.

Application of dust suppressants to cover exposed soil (dirt roads, material stockpiles).

Covering of trucks during transportation of materials (e.g., it is assumed covering stockpiles on barges would not be needed

since the material would be wet).

The Joso upland disposal contingency site would be used for dredged material that is unsuitable for in-water disposal (e.g.,

elevated ammonia levels, etc.) to create shallow-water fish habitat. Any material generated during the construction of the 3-foot

(0.9-m) levee raise that cannot be used to create shallow-water fish habitat would be transported to the Joso site. All materials

transported to the Joso site would be managed for the control of fugitive dust as discussed in alternative 3 below.

4.11.1 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

This alternative considers the same dredging activities as alternatives 1 and 2, but with upland disposal instead of in-water disposal.

The 3-foot (0.9-m) levee raise described as a part of alternative 2 would be included with this alternative. Thus, the primary air

quality regulatory focus would be on prevention of material from becoming airborne during transport, off-loading, and upland

placement at the Joso site (and/or other sites, if applicable), and during levee and roadway construction. The BMPs that would be

implemented to control dust are summarized as follows:

Soil stockpiles would be covered during construction phase.

Dredged material would be covered during transportation to upland disposal sites.

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Unpaved haul roads would be treated with a soil-stabilizing chemical or wetted with water to reduce airborne particulates from

tire entrainment during construction.

Containment berms at upland disposal sites would be covered with geotextile to prevent erosion and reduce permeability and

would then be covered with topsoil and seeded.

Upland disposal site restoration would be achieved by placing topsoil on final slopes and re-seeding with native grasses as

part of a continuing restoration program.

Site restoration would be achieved by re-establishing vegetation similar to the plant species present in surrounding areas that

will enhance wildlife habitat development.

Potential impacts associated with levee construction in the Lewiston area would be the same as those described under alternative 2.

With the implementation of dust control measures, activities associated with alternative 3 levee construction activities are not

anticipated to adversely affect air quality.

There is potential for short duration air quality impacts in the immediate area (Lyons Ferry Hatchery and Marina) of the Joso site

from fugitive dust and odor of decomposing organic matter in wet sediment material; however, these impacts would be abated due

to placement of dredged materials in the temporary de-watering area in the winter and early spring when temperatures and wind are

not conducive to creating airborne particulates.

4.11.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

Air quality conditions are anticipated to be similar to those described for the other alternatives. No additional impacts associated with

implementation of alternative 4 are anticipated.

4.11.5 Mitigation

Minor air quality impacts are anticipated. Mitigation measures detailed in sections 4.11.2 and 4.11.3 above could be implemented as

needed.

4.12 NOISE

4.12.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Under this alternative, mechanical dredging and in-water disposal would be continued. No modifications would be made to the

levees that protect Lewiston, Clarkston, and Asotin. As discussed in section 3.12, existing dredging, transport, and disposal activities

are exempt from noise regulations. It is anticipated that future activities would also be exempt from applicable regulations (see section

3.12.3). Minor, direct, short-term impacts are anticipated to result from construction activities.

4.12.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

As described for alternative 1, existing dredging, transport, and disposal activities are not anticipated to have significant noise

impacts. Transport via water would be monitored. It is anticipated that continued maintenance dredging activities would also be

consistent with applicable regulations and would have a minor, direct, short-term effect. Construction and operation of the Joso

upland disposal contingency site would generate noise, primarily during daylight hours. However, the site is remote and there

should not be significant noise impacts. Levee construction would occur primarily during daytime hours. Typical construction noise

would be exempt from regulation as discussed in section 3.12.3 and are anticipated to be localized , minor short-term impacts.

4.12.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

Potential impacts from maintenance activities would be the same as those described for alternative 2. Upland disposal would occur

primarily during daytime hours and would have minor, direct, short-term effects during site work and disposal activities.

4.12.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

Noise conditions are anticipated to be similar to those described for the other alternatives. Construction and maintenance activities

would be exempt from regulation as discussed in section 3.12.3 of this document. No impacts associated with implementation of

alternative 4 are anticipated.

4.12.5 Mitigation

Only minor impacts are anticipated; thus, no mitigation is proposed.

4.13 AESTHETICS

4.13.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Alternative 1 involves dredging to maintain the navigation channel, access channels to ports and moorages, public recreation areas,

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irrigation intakes for HMUs, and flow conveyance capacity of the Lower Granite reservoir with in-water disposal of dredged material.

This alternative is anticipated to have a direct impact on aesthetics in the area where dredging and disposal operations are taking

place. This effect would result from the presence of dredging equipment in the river and the turbidity plume from in-water disposal.

This impact would occur during the duration of the dredging operation and would have a minor effect on the visual quality of the

project area, but would occur on a regular basis over a 20-year period as dredging and disposal activities are undertaken. This

alternative is not expected to change viewing patterns for the aesthetic resources in the project area.

4.13.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

Alternative 2 involves dredging as described in alternative 1 and a 3-foot (0.9-m) levee height increase in the Lewiston-Clarkston

area, with in-water disposal of dredged material to create shallow-water fish habitat. This alternative is anticipated to have a direct

impact on the aesthetics of the project area, both where the dredging and disposal operations are occurring and in the areas of the

levee modification. Impacts due to levee modification are expected to be both short-term (due to construction activities) and

long-term (due to raising of the levees). As with alternative 1, this effect would occur during the dredging operations. Levee

modifications would affect the riverfront park facilities and would present moderate impacts to both visual quality and viewing

patterns. Levees would be revegetated.

Disposal of unsuitable material at the upland Joso site, if required, would have aesthetic impacts discussed in section 4.13.3 below.

Effects would be minor and the aesthetic qualities of the site would be restored in part by proposed site restoration following

disposal operations.

4.13.3 Alternative 3 -Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

Alternative 3 involves dredging as described in alternatives 1 and 2, a 3- foot (0.9-m) levee height increase in the Lewiston-Clarkston

area, with upland disposal of dredged material. This alternative is anticipated to have a temporary, direct impact on the aesthetics of

the project area, both where the dredging and disposal operations are occurring and in the areas of the levee modification. Levee

modifications that affect the riverfront park facilities would affect both visual quality and viewing patterns. However, these impacts

would be temporary and localized and are not significant.

Under this alternative, the dredged material from all reservoirs would be disposed of at the Joso site in the Lower Monumental

reservoir. Disposal activities would have a direct, long-term effect on the aesthetics of the disposal site and the areas immediately

surrounding the site from which the site can be viewed. Portions of the Joso site are visible from SR 261, and the site can also be

viewed by boaters, fishermen, and other recreational users in that portion of the river. Disposal operations on the site would be set

back 600 feet (182.9 m) from the shoreline, thus lessening the visual impacts to river users. When completed, the area filled by

dredged material would be restored by covering it with topsoil and by planting native plant species, thereby restoring some of the

aesthetic values of the site. While the proposed disposal operations would directly impact the aesthetic quality of the Joso site, the

effects would be minor due to the fact that the site is not highly visible to viewers and would be restored upon completion of

disposal operations.

4.13.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

Alternative 4 would have similar impacts to aesthetics as alternatives 1 and 2. In addition, beneficial use of dredged material would

potentially have a long-term positive effect on aesthetic resources if the material were used for wetlands or habitat restoration.

Proposed woody riparian habitat creation along the lower Snake River would have a long term, beneficial effect on the aesthetics of

the shoreline area.

4.13.5 Mitigation

Since anticipated effects to aesthetics are considered minor and temporary, no mitigation is proposed for alternatives involving

dredging and in-water disposal. Landscaping and site restoration is planned for levee modifications and upland disposal activities.

4.14 NATIVE AMERICAN TRIBES AND COMMUNITIES

Although DMMP actions would occur in the five study area reservoirs over its 20-year life, most dredging activities and the majority of

any in-water disposal would occur in the Lower Granite reservoir. Therefore, any direct effects stemming from the DMMP would most

likely be generated within Nez Perce ceded lands.

By contrast, any effects to other resources are expected to be limited to the study area. Impacts to terrestrial wildlife and habitats

are expected to be indirect, short-term, and minor since DMMP actions would not be continuous or confined to a given location.

Important habitat attributes such as avian perch trees would not be removed. No socioeconomic effects to regional populations,

employment, or income are anticipated and no changes to reservoir uses are expected under the DMMP.

Water quality impacts from DMMP activities are expected to be temporary, but would result in direct negative effects due to turbidity

plumes caused by dredging and in-water disposal. Greater sediment plumes are expected from dredging operations. Although no

significant changes in water quality from toxic substances are anticipated, monitoring is recommended to address the potential

presence of toxic substances and ambient elutriate in sediments prior to dredging. Dredging and in-water disposal of dredged

materials could result in habitat changes that are beneficial, neutral, or even detrimental to different aquatic species depending on

given species responses and needs (Bennett et al., 1997 and1998). Constructing more shallow water habitat could change water

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quality factors. Shallow-water temperatures, currently below optimum for the growing season of resident game fish, would be

increased and possibly enhance resident game fish habitat conditions and population numbers.

Concerns over potential impacts to cultural resources would be focused on damage to cultural sites from dredging actions or

covering sites with too much sediment as a result of disposal activities. As now planned, dredging would be limited to existing

navigation channels and/or would not go below accumulated sediments into original riverbed. Likewise, disposal activities either

upland or in- water would avoid known sites. (However, sediment drift from in-water disposal could result in the eventual covering of

sites with too much material.) Such actions would help to reduce the chances of impacting cultural sites.

4.14.1 Alternative 1 - No Action (No Change) - Maintenance Dredging With In-Water Disposal

Dredging and disposal activities are expected to have short-term, minor effects on aquatic species. These effects are described in

greater detail in sections 4.1 and 4.3. The Corps has determined alternative 1 "may effect and would likely adversely affect" six of the

seven ESA-listed salmonid ESUs. Macroinvertebrates, a food source for fish, would be removed by dredging but would recolonize

both dredging and in-water disposal locations. These food species would be available during the following anadromous fish outmigration season. Water quality would not be diminished and, given Van Oosten’s (1945) literature survey, sediment plumes created

by DMMP actions would be harmless to fish.

It is not anticipated that dredging actions would impact cultural resources (see section 4.5). Cultural resources associated with

in-water disposal areas could potentially experience minimal and indirect effects over the long term due to uncertainty associated

with how dredged material deposits may be redistributed by reservoir currents. Unknown cultural properties would not be protected

from DMMP activities and, consequently, cultural values may be impacted.

4.14.2 Alternative 2 - Maintenance Dredging With In-Water Disposal to Create Fish Habitat

and a 3-Foot (0.9-m) Levee Raise

Impacts from dredging would be similar to alternative 1. The impacts of in- water disposal of dredged materials on water quality and

cultural resources would also be similar to alternative 1. However, the overall change to study area tribal fisheries is fundamentally

uncertain.

4.14.3 Alternative 3 - Maintenance Dredging With Upland Disposal and a 3-Foot (0.9-m) Levee Raise

Dredging activities under this alternative would be the same as for alternative 2. The primary difference is using upland disposal at

Joso instead of in-water disposal. This alternative would limit risks to fish habitats caused by in- water disposal operations. No

aquatic benefits are expected to accrue from upland disposal and terrestrial benefits would be limited to the restoration of the large

existing borrow pit at the Joso upland disposal area. This alternative would provide the greatest protection to cultural properties and

be the least likely to impact undocumented properties.

4.14.4 Alternative 4 - Maintenance Dredging With Beneficial Use of Dredged Material and a 3-Foot (0.9-m) Levee Raise

This alternative would have effects similar to alternative 2 except there would be an emphasis on beneficial uses of dredged

materials, including constructing shallow-water fish habitat. Decisions for disposing of dredged materials would be made for each

dredging action.

4.14.5 Mitigation

Mitigation would be the same as discussed in sections 4.1.8, 4.3.1.3, and 4.5.2.

4.15 CUMULATIVE EFFECTS

The National Environmental Policy Act and the Council on Environmental Quality’s regulations require Federal agencies to consider

the cumulative impacts of their actions on the natural and human environment. Cumulative effects are those environmental

consequences that result from the incremental impact of a proposed action when added to other past, present, and reasonably

foreseeable future actions, regardless of the agencies or individuals that may undertake them. Cumulative impacts can also result

from individually minor, yet collectively substantial, actions that take place over a period of time.

4.15.1 The DMMP/EIS Cumulative Effects

This DMMP/EIS considers alternative strategies for long-term management of the navigation channel of the lower Snake River and

McNary reservoirs, the potential impacts of recurring cycles of dredging and dredged material management activities over a 20-year

period. It also considers modifications to the existing levees in the vicinity of Lewiston, Idaho, to provide enhanced flow conveyance

capacity.

The cumulative effects analysis considered whether the proposed action and other past, present, and reasonably foreseeable future

actions, when considered over the 20-year term of the DMMP could potentially have cumulative impacts on environmental

resources. The scope of this analysis includes the resource areas described in sections 4.1 through 4.14.

Cumulative impact analyses have been incorporated throughout the DMMP/EIS. The documentation of existing environmental

conditions in Section 3 describes each environmental resource area with respect to current and historic conditions and activities that

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have contributed to the current status of the resource. The existing conditions of environmental resources, particularly in a highly

modified system such as the lower Snake River and McNary Reservoirs, largely result from past and present actions. In particular,

the lower Snake and mid-Columbia river systems have been significantly changed since the construction of the McNary and lower

Snake River lock and dam projects.

The geographic scope of this cumulative effects analysis is generally consistent with that of the overall environmental analysis for

this DMMP/EIS. Actions outside the DMMP project study area have the potential to impact some resources within the lower Snake

and McNary reservoirs and, as such, are considered in this cumulative effects analysis. Similarly, the actions proposed under this

DMMP have the potential to impact resources outside of the study area, and this is likewise considered in the cumulative effects

analysis.

As noted above, the lower Snake and mid Columbia river systems have been substantially altered by construction of dams and

levees, as well as through other human activities such as agriculture and urban development. Consideration of the historic actions

that have modified the river system is important in establishing the baseline for the evaluations undertaken for this DMMP/EIS.

These baseline conditions are presented in Section 3 of this EIS. The temporal scope, or timeframe, of this cumulative effects analysis

begins with the construction of the McNary and lower Snake River lock and dam projects, and spans the 20-year planning horizon

of the DMMP. Since this DMMP evaluates dredging and dredged material management over a 20-year timeframe, the cumulative

effects analysis considered whether the potential effects on resources from repeated activities over 20 years would be cumulatively

significant. That is, would individually minor impacts recurring regularly over 20 years potentially result in significant environmental

effects. In addition, relevant past and present activities, and reasonably foreseeable future actions within and, if appropriate, beyond

the study area, were considered to determine whether impacts from DMMP alternatives would have cumulative environmental

effects when added to those actions.

Past, present, and reasonably foreseeable projects or actions that could, when added to the proposed plan alternatives, result in

cumulative impacts include:

Construction of McNary Dam and the four lower Snake River dams and the formation of the reservoirs behind the dams

Agricultural practices and urban and industrial development within and adjacent to the study area

Past and present dredging and dredged material disposal activities, including dredging undertaken by the Corps for

navigation maintenance or flow conveyance, as well as other dredging including ports, commercial, and recreational facilities

within the study area.

Levee construction and modification.

Re-licensing of dams within the Columbia/Snake River system.

The Lower Snake River Juvenile Salmon Migration Feasibility Study recommendations, and other salmon recovery efforts in

the study area.

Columbia River Channel Improvement Project.

4.15.1.1 Construction of the Five Corps Dams

As stated previously, construction of McNary Dam and the four lower Snake River dams changed portions of the Columbia and

Snake Rivers from free- flowing rivers to a series of slack water reservoirs. The formation of the reservoirs altered most of the

resource areas that are discussed in Sections 3 and 4 of this DMMP/EIS. For example, the reservoirs flooded farmland and wildlife

habitat, provided public access to the shoreline, altered transportation to include shipment by barge, provided for additional port

and industrial development, required relocation of some communities, and required construction of levees to protect other

communities. These effects are expected to continue for McNary dam and reservoir over the 20-year period of the DMMP. These

effects are also expected to continue for the lower Snake River dams over the 20-year period pending any decisions made through

the Lower Snake River Juvenile Salmon Migration Feasibility Study (see Sections 1.6 and 4.15.1.6).

4.15.1.2 Land Use Practices

Land use practices within and adjacent to the study area have changed somewhat since construction of McNary Dam and the lower

Snake River dams. Prior to the dams, much of the land adjacent to the rivers was used for crops, orchards, or grazing. There were

several small communities along the rivers as well as the larger communities such as Lewiston, Clarkston, and the Tri-Cities. The

reservoirs eliminated most agricultural use of the lower Snake River canyon and McNary project lands along the mid-Columbia

River. Dryland farming and grazing continued on land adjacent to the Corps property. In recent years, some of that land has been

converted to irrigated crops, orchards, and fiber farms. Agricultural practices often involve the use of pesticides and chemicals and

can result in soil erosion. Runoff from agricultural lands can deposit sediment and chemicals in the reservoirs. Agriculture will likely

continue to be a major land use adjacent to the study area during the 20-year period.

Urban and industrial development has occurred mainly in the Lewiston/Clarkston area and the Tri-Cities area with some additional

industrial development occurring at port sites. Urban development has created a demand fo r use of waterfront property for

commercial and recreational purposes. Urban development has also resulted in more stormwater runoff, much of which is

discharged into the reservoirs. Industrial development has involved placement of fill material and pilings to create docking facilities.

Some industrial facilities discharge their wastewater into the reservoirs as permitted by state and federal regulatory agencies. These

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types of activities are expected to continue in these areas during the 20-year period.

4.15.1.3 Dredging and Dredged Material Management

Previous Corps dredging of the lower Snake River and McNary reservoirs is summarized in table 1-1. Dredging events have ranged

from a few thousand cubic yards to almost 1 million cy (764 555 m3). Between 1996 and 1998, the Corps dredged 313,636 cy (239

791.9 m3) of sediments, primarily from Lower Granite reservoir. Other, smaller-scale dredging and disposal activities have taken

place within the study area as well. This DMMP/EIS considers future dredging scenarios of roughly this order of magnitude

[approximately 340,000 cy (259 948.7 m3) every 2 years]. The Corps has conducted a series of studies to evaluate appropriate

in-water and upland disposal sites for dredged material and the effectiveness of habitat creation with dredged material deposited

in-water in shallow and mid-depth areas.

Plan alternatives considered in combination with past and present dredging and disposal activities are not anticipated to

cumulatively have significant effects on the resources analyzed in this DMMP/EIS. Historically, some port facilities and recreational

marinas on the lower Snake River and McNary reservoirs have used dredging to maintain adequate depths at the ports or marinas

(e.g., moorages, turning basins, etc.) or the access channels from port facilities to the authorized navigable channel (see Table 1-1).

The Corps has conducted dredging for the ports, generally on a cost-reimbursable basis. Additional port and marina facilities would,

most likely, require some level of dredging over the 20- year timeframe covered by the DMMP/EIS.

Future dredging of port and marina facilities, in combination with the dredging and disposal scenarios considered in this DMMP/EIS,

is not expected to have significant cumulative environmental effects. While additional port and marina dredging would increase

dredging activities and dredged material quantities requiring disposal, it is not anticipated that these factors would result in

substantially greater amounts of dredging or dredged material. Environmental effects are expected to be of the same scope and

magnitude as those documented in this DMMP/EIS, and are not anticipated to be cumulatively significant when considered in

combination with other actions.

4.15.1.4 Levee Construction and Modification

The proposed nominal 3-foot (0.9-m) levee raise (alternatives 2 through 4) involves raising the elevation of the existing levees in the

Lewiston area to provide enhanced flow conveyance capacity through this portion of Lower Granite reservoir. The proposed levee

raise would add 3 feet (0.9 m) (maximum) in elevation to the top of the existing levee in some locations. At most points along the

levees, the raise would be much less than 3 feet (0.9 m). The proposed levee raise is not anticipated to result in environmental

effects (particularly aesthetic effects) that are significant when considered cumulatively with the existing levees, or with other actions

of the DMMP.

4.15.1.5 Dam Re-licensing

The Hells Canyon Complex Dam on the Snake River, upstream of the study area, will require re-licensing by the Federal Energy

Regulatory Commission in 2005. Re- licensing could potentially include requirements that would change operations of that dam,

particularly with respect to fish passage and endangered species concerns. At this time, any changes brought on by dam

re-licensing that could contribute to cumulative environmental effects are unknown and cannot be considered in this analysis.

4.15.1.6 Lower Snake River Juvenile Salmon Migration Feasibility Study Recommendation

Several river drawdown scenarios were studied by the Corps in the Lower Snake River Juvenile Salmon Migration Feasibility Study.

The Corps (Portland District) also studied drawdown of John Day Dam on the mainstem Columbia River downstream of McNary

Dam. These studies were in response to the listing of several salmon species as endangered under the ESA. The study of

management of the lower Snake River system, including drawdown, is discussed in section 1.6 of this DMMP/EIS. The Corps has

issued a final EIS which documents a recommended plan of system improvements to facilitate "adaptive migration."

The preferred alternative that has resulted from the Lower Snake River Juvenile Salmon Migration Feasibility Study process will

affect management of the lower Snake River and McNary reservoirs. This DMMP/EIS incorporated several assumptions regarding

the future operations of the study area reservoirs, including continuing navigation within the 20-year planning horizon for the

DMMP/EIS. The outcome of the Feasibility Study process (to this point) would be consistent with these assumptions while furthering

salmon recovery goals. Programmed future "checkpoints" will evaluate the progress made on salmon recovery, and changes to

recovery efforts may be made based on these evaluations. Based upon reasonably foreseeable future actions with respect to

salmon recovery, no significant cumulative effects are expected.

4.15.1.7 Columbia River Channel Improvement Project

The Columbia River Channel Improvement Project was originally presented in the Final Integrated Feasibility Report for Channel

Improvements and Environmental Impact Statement, dated August 1999. In December 1999, Congress authorized the deepening of

the Columbia and Lower Willamette Rivers Federal Navigation Channel to 43 feet [Section 101(b)(13) of the Water Resource

Development Act of 1999]. The authorized plan modifies the existing federal navigation project for the Columbia and Willamette

Rivers and provides for construction of ecosystem restoration features. Several additional ecosystem restoration features and

research actions are proposed for implementation to benefit the recovery of listed salmonids and other fish and wildlife resources, to

avoid impacts to marine resources at the Deep Water Ocean Disposal Site, and to retain sand in the estuary. Creating these

restoration features will use sand that would have been disposed of in the Deep Water Ocean Disposal Site. Under the revised plan,

no ocean disposal is proposed until 10 years after construction. Construction volumes were updated using December 2001 and

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January 2002 hydrographic survey data. Other items updated include a reduction in rock excavation, utility relocations, information

for smelt and sturgeon gained from research data collection conducted with the federal and state resource agencies, and

modification to some of the upland disposal sites to avoid impacts to resources and habitat. The Corps published a Draft

Supplemental Integrated Feability Report and Environmental Impact Statement in July 2002.

The NMFS and USFWS May 2002 Biological Opinions discuss such potential development and its potential impacts (e.g., increased

localized demand for electricity, water and buildable land with indirect effects to water quality; and, the increased need for

transportation, communication and other infrastructure;) on listed species, as well as state, local, tribal and private actions to benefit

listed species. The NMFS and USFWS cumulative effects analyses are incorporated herein by reference (Chapters 6 and 8,

respectively, of the USFWS and NMFS Biological Opinions). Given the large geographic area involved and the uncertainties

associated with state, local, tribal and private actions, the precise nature and timing of future development, and its environmental

impact, are extremely difficult to predict. However, given the minimal adverse effects (if any) anticipated for the entire Columbia River

channel improvement project as described in this document (i.e., including the ecosystem restoration features and mitigation

measures), with the exception of anticipated losses of agricultural lands discussed in the Final IFR/EIS, the project is not anticipated

to contribute significantly to any adverse cumulative effects resulting from unrelated development projects. Further, all significant

future development will likely be subject to additional independent environmental reviews by state and federal agencies under

NEPA, the Clean Water Act, the ESA and similar state programs.

Other ongoing projects directly affect the Columbia River and its environment. These include operation of the Federal Columbia

River Power System (FCRPS) and maintenance of the Mouth of the Columbia River federal navigation project (MCR). The potent ial

effects of these projects have been studied in detail. Information on the FCRPS can be found in the December 2000 Biological

Opinions issued by NMFS and USFWS for that program. As noted above (Section 7.5.5), the NMFS May 2002 Biological Opinion for

channel improvement expressly refers to reasonable and prudent measures from the FCRPS Biological Opinion in order to better

integrate compliance measures for the two projects.

In January 2002, the Corps submitted the BA (December 2001) for the Columbia River channel improvement project to the NMFS

and USFWS. The BA included actions associated with dredging and deepening, including compliance measures to minimize

incidental take of listed species; monitoring actions to ensure deepening and disposal have minimal effects on listed fish and their

habitats, and adaptive management to respond to impacts discovered through the monitoring program. Ecosystem restoration

features and research actions involve numerous proposals to improve existing habitat conditions in the lower Columbia River and

estuary, and research activities to increase knowledge of the river and estuary ecosystem.

On May 20, 2002, the NMFS and the USFWS transmitted their final Biological Opinions to the Corps. These opinions determined

that the channel improvement project, including dredging, disposal, monitoring, adaptive management research, and ecosystem

restoration, is not likely to jeopardize the continued existence of 13 listed and one proposed fish species, bald eagles, or Columbian

white-tailed deer. In addition, the services concurred that the project is not likely to adversely affect Steller sea lions. As discussed in

the Channel Improvment documents, the compliance measures, ecosystem research actions and ecosystem restoration features

that are part of the channel improvement project are intended to not only avoid and minimize any adverse environmental effects, but

also to provide net environmental benefits for several environmental resources. Accordingly, channel improvement is not anticipated

to contribute to any cumulative adverse environmental effects associated with FCRPS, MCR, or the DMMP/EIS related activities.

4.15.2 Cumulative Effects Findings

The likely cumulative effects of the resource areas examined in this DMMP/EIS, within the context of both the 20- year timeframe of

the plan and other past, present, and reasonably foreseeable future actions are summarized below. The cumulative effects of each

of the four alternatives are expected to be similar except as noted.

Aquatic Resources – A substantial number of major changes have occurred to the aquatic resources since dam construction.

In addition to the changing of free flowing rivers to a more lacustrine system, the dams have also changed temperature

regimes, although currently the high water temperatures of concern are greatly influenced from operations upstream of the

lower Snake reservoirs. Anthropogenic activities (including, but not limited to sport fisheries management) have increased the

number of non-native species, many of which (bass, walleye, crappie, etc.) now prey upon other small native fish, including

migrating and rearing salmonids. In addition, industry in the project area has increased the amount of point source pollution,

and increased urban development, forestry and agricultural practices have increased non-point source pollution as well.

Construction of railroads, roadbeds and levees has changed the interactions of the hydrologic zone including the hydrologic

functioning of the flood plain and the development and maintenance of a healthy riparian zone.

Future actions associated with dredging and other anticipated activities in the near term include environmental restoration

through the removal of levees, developing riparian shoreline areas and building up mid-depth benches to shallow depth for

better salmonid habitat. However, urban development is anticipated to continue, the lower Snake River dams are expected to

stay in place at least through their economic life, and sedimentation from the various activities in the upper watershed is

expected to continue.

Recurring dredging and management activities proposed in the DMMP would have repeated, minor resource impacts, but

these impacts would not be cumulatively significant. Creation of riparian and submerged habitat areas could have cumulative

benefits to aquatic resources. Upland disposal at the Joso site would have no cumulative effects on aquatic resources.

Terrestrial Resources – The effects of plan alternatives on terrestrial resources would be minor, and may be cumulatively

positive over the long-term if beneficial uses of dredged material involve substantial efforts to restore terrestrial ecosystems

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(such as those of the proposed woody riparian program).

Endangered Species – Plan alternatives would not have cumulatively significant adverse impacts on currently listed threatened

or endangered species. Proposed beneficial uses of dredged material may have beneficial long-term effects for listed

anadromous fish species, particularly when considered in combination with other current and proposed salmon recovery

efforts.

Recreation – The plan alternatives are anticipated to result in minor, short-term impacts to recreation resources. Some positive

effects (such as maintaining recreational boat basins) would result from the proposed alternatives. No adverse cumulative

effects on recreation are expected to result from the DMMP alternatives.

Cultural Resources – Cumulative impacts to cultural resources could occur over the term of the DMMP through repeated

placement of dredged material on potential submerged cultural resources sites. However, these impacts are not anticipated to

be significant since known cultural resource sites will be avoided and the Corps would conduct on-going coordination with

tribal and state cultural resources authorities. Upland disposal of dredged material would not be expected to have cumulative

effects on cultural resources as dredged material would not be placed on cultural sites.

Socio-economics - In general, positive socio-economic effects are expected to result from the DMMP alternatives. No

substantial changes to existing socio-economic conditions or trends are anticipated to result from the DMMP alternatives when

considered with other actions.

Transportation – The DMMP alternatives would all result in continued commercial navigation on the lower Snake River and

McNary Reservoirs. No substantial changes to the regional transportation are anticipated to result from the DMMP alteratives.

Geology and soils – DMMP alternatives would have cumulative effects on soils based on repeated dredging and management

of dredged sediments, particularly if beneficial uses dredged materials are maximized for purposes, such as the proposed

woody riparian program. Such cumulative effects would not be significant and, in some cases, may be beneficial, through

stabilization of shoreline areas. Also worth noting is the opportunity presented through the DMMP process (and, in particular,

through the Local Sediment Management Group) to begin addressing sediment sources and contributions to the lower Snake

River system and McNary reservoir.

Water Quality/Water Resources – Each dredging cycle would have minor short-term adverse impacts on water quality and

sediment resulting from dredging and ma nagement of dredged materials. However, dredging and dredged material

management impacts would not result in cumulatively significant adverse impacts to water quality from the plan alternatives.

Other past, present, and future activities, including continued and future wastewater and stormwater discharges would affect

water quality. However DMMP water quality and water resources impacts, when considered in combination with other actions,

are not anticipated to result in significant adverse cumulative effects.

Hazardous, Toxic, and Radioactive Wastes (HTRW) – The DMMP alternatives would not have adverse HTRW impacts, and no

cumulative effects with respect to HTRW are anticipated to result from implementation of DMMP.

Air Quality – No cumulatively negative air quality impacts would result from the DMMP alternatives. Proposed dredging and

dredged material management activities and the proposed levee modifications would result in short-term increases in

emissions. However, neither the repeated dredging and disposal activities nor the combination of DMMP-related activities and

other actions would have cumulatively significant adverse air quality impacts.

Noise – Noise impacts associated with DMMP alternatives would be localized and short-term. No cumulative noise impacts are

expected to result from DMMP alternatives.

Aesthetics – The proposed alternatives would have a cumulative, yet localized, impact on aesthetics with respect to the

proposed levee raise. Historically, construction of the levees in the Clarkston/Lewiston area as an upstream extension of Lower

Granite Dam has resulted in changes to the aesthetics of riverfront areas in the surrounding communities. The proposed levee

raise would involve a portion of the existing levee system and would result in a maximum levee raise of three feet (less than

one meter). The proposed levee raise would not result in significant cumulative impacts on study areas aesthetics. Creation of

woody riparian habitat in any of the reservoirs would expand or restore riparian vegetation to the shoreline. Shoreline

restoration along any of the reservoirs would eliminate eroding cutbanks and provide a sloping, vegetated bank.

Native American Tribal Communities –The DMMP alternatives, while maintaining the navigation channel, also feature

opportunities to restore previously affected elements of the river systems, particularly that restore ecosystem features. The

recommended plan, for example, features maximization of beneficial use of dredged material which would benefit endangered

fish species that are of profound cultural and spiritual importance to Native American communities, as well as an important

food source. Beneficial uses and other means of dredged material management proposed in the DMMP would represent

positive steps to aid the resources valued by these communities.

4.15.3 Mitigation

No cumulatively significant adverse environmental effects are anticipated to result from the alternatives considered. Therefore, no

mitigation specific to cumulative impacts is proposed at this time. Proposed beneficial uses and mitigation measures outlined in the

DMMP would avoid, reduce, or otherwise mitigate environmental impacts of the proposed action that could result in cumulative

impacts. If changes in the conditions or assumptions of this cumulative effects analysis were to change over the planning timeframe

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of 20 years, the potential for cumulative environmental effects would be revisited by the Corps.

Section 5

Compliance with Applicable Environmental Laws and Regulations

This DMMP/EIS is in compliance with environmental laws and Executive Orders as described, but not limited to those listed below:

5.1 FEDERAL STATUTES

5.1.1 American Indian Religious Freedom Act (AIRFA)

The AIRFA of 1978 (42 U.S.C.A. 1996) established protection and preservation of Native Americans' rights of freedom of belief,

expression, and exercise of traditional religions. Courts have interpreted AIRFA to mean that public officials must consider Native

Americans' interests before undertaking actions that might harm those interests. The Corps will continue to coordinate with affected

Native American Tribes on this study and future implementation plans.

5.1.2 Archeological Resources Protection Act

The Archeological Resources Protection Act (16 U.S.C. 470aa-470ll) provides for the protection of archeological sites located on

public and Indian lands, establishes permit requirements for the excavation or removal of cultural properties from public or Indian

lands, and establishes civil and criminal penalties for the unauthorized appropriation, alteration, exchange, or other handling of

cultural properties.

The Corps will continue to protect archeological resources and sites on its lands. The Corps will configure its maintenance dredging

and dredged material disposal activities to avoid known cultural properties.

5.1.3 Clean Air Act

The Clean Air Act (CAA) (42 U.S.C. 7401 et seq.), amended in 1977 and 1990, was established "to protect and enhance the quality

of the nation's air resources so as to promote public health and welfare and the productive capacity of its population." The CAA

authorizes the EPA to establish the NAAQS to protect public health and the environment. The CAA establishes emission standards

for stationary sources, volatile organic compound emissions, hazardous air pollutants, and vehicles and other mobile sources. The

CAA also requires the states to develop implementation plans applicable to particular industrial sources.

Upland disposal of dredged material and levee construction both have the potential to generate dust. With the implementation of

BMPs, activities associated with the alternatives are not anticipated to adversely affect air quality.

5.1.4 Coastal Zone Management Act

The Coastal Zone Management Act of 1972 (16 U.S.C. 1451-1564) requires that Federal actions be consistent, to the maximum

extent practicable, with approved state coastal zone management programs. A state coastal zone management program (developed

under state law and guided by the Act) sets forth objectives, policies, and standards to guide public and private uses of lands and

waters in the coastal zone. The coastal zone as defined in the Act extends inland as far as necessary to account for factors that

influence shorelines. Washington and Oregon have approved coastal zone management programs, both of which list seven types of

Federal activities directly affecting the coastal zone. The upper boundary of the coastal zone is downstream of Bonneville Dam.

The DMMP/EIS alternatives would have little effect on water levels or river uses downstream of Bonneville Dam and, therefore, all

alternatives are in compliance with the Act.

5.1.5 Endangered Species Act (ESA)

The ESA (16 U.S.C. 1531-1544), amended 1988, established a national program for the conservation of threatened and endangered

species of fish, wildlife, and plants and the habitat upon which they depend. Section 7(a) of the ESA requires Federal agencies to

consult with the USFWS and NMFS, as appropriate, to ensure that their actions are not likely to jeopardize the continued existence

of endangered or threatened species or adversely modify or destroy their critical habitats.

Section 7(c) of the ESA and the Federal regulatio ns on endangered species coordination (50 CFR &sec; 402.12) require that

Federal agencies prepare BA's of the potential effects of major actions on listed species and critical habitat. The Corps has been

and continues to consult with USFWS and NMFS concerning listed species that could be affected by the actions addressed in this

DMMP/EIS.

The Corps has consulted with the USFWS and NMFS regarding listed species in the study area. The BA's have been prepared (see

appendix F - Biological Assessment for Anadromous Fish Species and appendix G - Biological Assessment for Non-Anadromous Fish

and Terrestrial Species) and forwarded to both agencies to address species and habitat impacts where applicable. USFWS

concurrence with the BA’s findings regarding the following listed species: Bull trout, bald eagle, McFarlane’s four-o’clock, water

howellia, and Ute ladies’ tresses is located in Appendix G. Those endangered or threatened species expected to be adversely

affected include the Snake River steelhead, Snake River fall chinook salmon, Snake River spring/summer chinook salmon, Snake

River sockeye salmon, Upper Columbia Basin steelhead, Middle Columbia Basin steelhead, and Upper Columbia Basin spring run

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chinook salmon. NMFS determined no jeopardy to listed species wo uld occur if reasonable and prudent measures were taken.

5.1.6 Farmland Protection Policy Act

The Farmland Protection Policy Act (7 U.S.C. 4201 et seq.) requires Federal agencies to identify and take into account the adverse

effects of their programs on the preservation of farmlands. None of the alternatives in this study would cause physical deterioration

and/or reduction in productivity of farmlands.

5.1.7 Federal Water Pollution Control Act (Clean Water Act)

The Federal Water Pollution Control Act (33 U.S.C. 1251 et seq.) is more commonly referred to as the Clean Water Act (CWA). This

act is the primary legislative vehicle for Federal water pollution control programs and the basic structure for regulating discharges of

pollutants into waters of the United States. The CWA was established to "restore and maintain the chemical, physical, and biological

integrity of the nation's waters." The CWA sets goals to eliminate discharges of pollutants into navigable water, protect fish and

wildlife, and prohibit the discharge of toxic pollutants in quantities that could adversely affect the environment. The Act has been

amended numerous times and given a number of titles and codifications.

Water Quality Certification for the recommended plan/preferred alternative will be requested from the regulating agencies for the

States of Washington, Idaho, and Oregon for each dredging activity, as appropriate. Corps actions involving the discharge of

dredged or fill materials into the waters of the United States will be in accordance with guidelines promulgated by the EPA in

conjunction with the Secretary of the Army under the authority of Section 404(b)(1) of the CWA. A Section 404(b)(1) Evaluation has

been prepared to address proposed in- water disposal actions on a programmatic basis and is included as appendix I in the

DMMP/EIS. Separate 404(b)(1) evaluations will be prepared for each dredging and in- water disposal activity and submitted to the

appropriate state(s) along with a request for water quality certification.

5.1.8 Federal Water Project Recreation Act

In the planning of any Federal navigation, flood control, reclamation, or water resources project, the Federal Water Project

Recreation Act (16 U.S.C.A. 4612 et seq.) requires that full consideration be given to the opportunities that the project affords for

outdoor recreation and fish and wildlife enhancement. The Act requires planning with respect to development of recreation potential.

Projects must be constructed, maintained, and operated in such a manner if recreational opportunities are consistent with the

purpose of the project.

Recreation sites have been developed at all of the Federal projects involved in the proposed action and are operated by a variety of

entities. Alternatives 2, 3, and 4 would have short-term, minor impacts on recreational trails due to levee modifications. None of the

alternatives considered in this DMMP/EIS are expected to have a significant, long-term impact on recreation facilities, activities, or

use patterns. There would be a positive effect on small boat harbors by continuance of maintenance dredging.

5.1.9 Fish and Wildlife Coordination Act (FWCA)

The FWCA of 1980 (16 U.S.C. 661 et seq.) requires consultation with USFWS when any water body is impounded, diverted,

controlled, or modified for any purpose. The USFWS and state agencies charged with administering wildlife resources are to

conduct surveys and investigations to determine the potential damage to wildlife and the mitigation measures that should be taken.

The USFWS incorporates the concerns and findings of the state agencies and other Federal agencies, including NMFS, into a

report that addresses fish and wildlife factors and provides recommendations for mitigating or enhancing impacts to fish and wildlife

affected by a Federal project. The Corps is not required to consult with the USFWS for existing water resource projects with

standard operation and maintenance.

The USFWS prepared an August 1988 Evaluation Report entitled "Lower Granite Reservoir Dredging Alternatives - Snake River,

Washington-Idaho." The USFWS provided comments on construction of a levee raise and dredge and disposal operations that have

been incorporated into this DMMP/EIS.

This DMMP/EIS has been coordinated with the USFWS and other Federal and state resource agencies. The Corps will continue to

consult with wildlife agencies through the adoption and implementation of the DMMP/EIS.

5.1.10 Fishery Conservation and Management Act of 1976

The Fishery Conservation and Management Act of 1976 (16 U.S.C. 1801-1882; 90 Stat. 331; as amended), also known as the

Magnuson Fishery Conservation and Management Act, established a 200-mile (321.9-km) fishery conservation zone, effective March

1, 1977, and established the Regional Fishery Management Councils consisting of Federal and state officials, including the

USFWS. The fishery conservation zone was subsequently dropped by amendment and the geographical area of coverage was

changed to the Exclusive Economic Zone, with the inner boundary being the seaward boundary of the coastal States. Columbia

River salmon and steelhead are found in this zone. Therefore, the potential effects of the alternatives on the fisheries in this zone

have been examined in section 4, Environmental Effects of Alternatives.

5.1.11 Land and Water Conservation Fund Act

The Land and Water Conservation Fund Act (LWCFA) (16 U.S.C.A. 4601-11) assists in preserving, developing, and ensuring

accessibility of outdoor recreation resources. The LWCFA establishes specific Federal fund ing for acquisition, development, and

preservation of lands, water, or other interests authorized under the ESA and National Wildlife Refuge Areas Act. Funds

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appropriated under the Act are allocated to Federal agencies or as grants to states and localities. Recreation facilities on the lower

Snake River as evaluated in the DMMP/EIS are not LWCFA- funded facilities.

5.1.12 Migratory Bird Conservation Act

The Migratory Bird Conservation Act (16 U.S.C. 715 et seq.) requires that lands, waters, or interests acquired or reserved for

purposes established under the Act be administered under regulations promulgated by the Secretary of the Interior. This act

involves conservation and protection of migratory birds in accordance with treaties entered into between the United States and

Mexico, Canada, Japan, and the former Union of Soviet Socialist Republics. It protects other wildlife, including threatened or

endangered species, and restores or develops adequate wildlife habitat. The migratory birds protected under this Act are specified

in the respective treaties. In regulating these areas, the Secretary of the Interior is authorized to manage timber, range, agricultural

crops, and other species of animals, and to enter into agreements with public and private entities.

Section 4.2, Terrestrial Resources, addresses affected avian species as well as other terrestrial species of concern.

5.1.13 National Environmental Policy Act (NEPA)

This DMMP/EIS was prepared pursuant to regulations implementing the NEPA (42 U.S.C. 4321 et seq.). The NEPA provides a

commitment that Federal agencies will consider the environmental effects of their actions. It also requires that an EIS be included in

every recommendation or report on proposals for legislation and other major Federal actions significantly affecting the quality of the

human environment. The EIS must provide detailed information regarding the proposed action and alternatives, the environmental

impacts of the alternatives, potential mitigation measures, and any adverse environmental impacts that cannot be avoided if the

proposal is implemented. Agencies are required to demonstrate that these factors have been considered by decision makers prior to

undertaking actions. Development of this programmatic DMMP/EIS is in compliance with NEPA requirements for the proposed

action. The NEPA compliance will be considered complete with the signing of a Record of Decision, currently anticipated in the

summer of 2002.

5.1.14 Native American Graves Protection and Repatriation Act (NAGPRA)

The NAGPRA (25 U.S.C.A. 3001) addresses the discovery, identification, treatment, and repatriation of Native American and Native

Hawaiian human remains and cultural items (associated funerary objects, unassociated funerary objects, sacred objects, and

objects of cultural patrimony). This Act also establishes fines and penalties for the sale, use, and transport of Native American

cultural items. Consistent with procedures set forth in applicable Federal laws, regulations, and policies, the Corps will proactively

work to preserve and protect natural and cultural resources, establish NAGPRA protocols and procedures, and allow reasonable

access to sacred sites.

5.1.15 The National Historic Preservation Act (NHPA)

Section 106 of the NHPA (16 U.S.C. 470) requires that Federal agencies evaluate the effects of Federal undertakings on historical,

archeological, and cultural resources and afford the Advisory Council on Historic Preservation opportunities to comment on the

proposed undertaking. The first step in the process is to identify cultural resources included in (or eligible for inclusion in) the NRHP

that are located in or near the project area. The second step is to identify the possible effects of proposed actions. The lead agency

must examine whether feasible alternatives exist that would avoid such effects. If an effect cannot reasonably be avoided, measures

must be taken to minimize or mitigate potential adverse effects. Historic properties are referred to as cultural properties in this

DMMP/EIS to make more clear to the reader that the term includes prehistoric, historic, and traditional age-related resources.

Cultural resource field investigations and literature searches have been conducted. The Corps' preliminary determination found that

DMMP/EIS dredging and disposal actions potentially could affect cultural properties. The Corps has consulted with the SHPOs of

Washington, Idaho, and Oregon, and other consulting parties, to determine the effects of the recommended action on cultural

properties on a programmatic basis and in developing measures that may be taken to avoid, minimize, or mitigate potential effects.

The Corps proposes to consult with the SHPOs and consulting parties each time a dredging activity is planned. The Corps has

received programmatic concurrences from Washington, Idaho, and Oregon SHPOs. Also, Washington and Idaho SHPOs have

provided concurrences with the proposed 2002-2003 dredging and dredged material management activities.

The following cultural resource protection laws were also considered in the preparation of this DMMP/EIS:

The Antiquities Act of 1906 (16 U.S.C. 431).

Historic Sites Act of 1935 (16 U.S.C. 461).

Reservoir Salvage Act of 1960 (16 U.S.C. 469).

Archeological and Historic Preservation Act of 1974 (16 U.S.C. 469a-1).

5.1.16 Pacific Northwest Electric Power Planning and Conservation Act (Northwest Power Act)

The Northwest Power Act was passed by Congress on December 5, 1980 (16 U.S.C. 829d-1). This law created the eight- member

Northwest Power Planning Council (NPPC), an interstate agency whose members are appointed by the Idaho, Montana, Oregon,

and Washington governors. The NPPC was entrusted with adopting a Fish and Wildlife Program for the Columbia River Basin by

November 1982 and preparing a 20- year Regional Electric Power and Conservation Plan by April 1983. These plans are periodically

updated and amended.

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The NPPC's Fish and Wildlife Program established a number of goals for restoring and protecting fish and wildlife populations in

the basin. These goals led to changes in the operation of the Coordinated Columbia River System during the mid-1980s. One of the

most notable changes resulted in the Water Budget, which provides for the release of specific amounts of water in the upper

Columbia and Snake Rivers to help juvenile salmon migrate downstream in the spring. More recently, the NPPC developed its own

proposals to protect threatened and endangered salmon stocks. The NPPC has completed amendments to its Columbia River Basin

Fish and Wildlife Program. The amendments adopted to date include main stem survival, harvest, production, habitat, and flow

measures that can be used to increase salmon and steelhead runs, and resident fish and wildlife measures. The Corps takes these

amendments into consideration when making operating plans.

The alternatives considered in the DMMP/EIS to maintain the existing authorized navigation channel and provide flow conveyance

capacity will have no long-term, adverse impacts on generation of electrical power in the Northwest or on fish and wildlife

populations present in the study area.

5.1.17 Pollution Control at Federal Facilities

In addition to their responsibilities under NEPA, Federal agencies are required to carry out the provisions of other Federal

environmental laws. To the extent applicable to an alternative presented in this DMMP/EIS, compliance with the standards

contained in the following legislation was included in this evaluation:

The Safe Drinking Water Act, as amended (42 U.S.C. 300F et seq.).

The Solid Waste Disposal Act (42 U.S.C. 6901 et seq.).

Oil Pollution Act (33 U.S.C. 2701 et seq.).

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as amended (42 U.S.C.

9601 [9615] et seq.).

The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as amended (7 U.S.C. 136 et seq.).

The Resource Conservation and Recovery Act (RCRA) of 1976, as amended (42 U.S.C. 6901 et seq.).

Toxic Substances Control Act (TSCA), as amended; Title 40 CFR Part 761, "Polychlorinated Biphenyls (PCBs) Manufacturing,

Processing, Distribution in Commerce, and Use Prohibitions" (15 U.S.C. et seq.).

The Noise Control Act of 1972, as amended (42 U.S.C. 4901 et seq.).

Occupational Health and Safety Act (29 U.S.C. 651 et seq.).

5.1.18 River and Harbor Act of 1899

Section 10 of the River and Harbor Act of 1899 (33 U.S.C. 401-418) regulates structures or work in or affecting navigable waters of

the United States including discharges of dredged or fill material. The planning of this proposed action has taken into consideration

the ability of boat/barge traffic to continue unobstructed.

Implementation of the proposed action would have a long-term beneficial effect on navigation in the study area. The public will be

notified each time the Corps proposes to perform in-water work in navigable water as part of the DMMP/EIS.

5.1.19 Wild and Scenic Rivers Act

The Wild and Scenic Rivers Act (16 U.S.C. 1278 et seq.) designates qualifying free-flowing river segments as wild, scenic, or

recreational. The Act establishes requirements applicable to water resource projects affecting wild, scenic, or recreational rivers

within the National Wild and Scenic Rivers system, as well as rivers designated on the National Rivers Inventory. Discharges into

streams, impoundments, diversions, channel alterations, and other measures can alter the stream discharge, velocity, and channel

dimensions. These hydraulic changes may cause modifications to the free- flowing character of the stream, resulting in loss or

diminution of its environmental values. The Act requires consideration of the impacts and consultation with the responsible agency

prior to implementation of a project.

Several rivers upstream of the study area are designated as Wild and Scenic Rivers, including portions of the Snake River, the

Grande Ronde River, and the Middle Fork of the Clearwater River. The Wild and Scenic portion of the Snake River extends from

Hells Canyon Dam (upstream) to the eastward extension of the north boundary of Section 1, Township 5 North, Range 47 East,

Willamette Meridian (downstream), approximately 67 miles (107.8 km). None of these rivers would be affected by the actions

recommended in this DMMP/EIS. Additionally, in 1988, through Public Law 100-677, Congress prohibited the construction of dams

"on the Snake River...from the eastward extension of the north boundary of Section 1, Township 5 North, range 47 East, Willamette

Meridian to the pool formed behind Lower Granite Dam...in order to further the purposes of the Wild and Scenic Rivers Act."

5.1.20 Wilderness Act

The Wilderness Act of 1964 (16 U.S.C.A. 1131 et seq.) established the National Wilderness Preservation system. Areas designated

as wilderness under the original Act and subsequent wilderness legislation are to be administered for the use and enjoyment of the

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public in such a manner as to leave them unimpaired as wilderness. Development activities are generally prohibited within

wilderness areas, and Federal agencies proposing actions must consider whether the effects of those actions would impair

wilderness values. Although there are Wilderness Areas in this basin, none are located on the lower Snake River.

5.2 EXECUTIVE ORDERS

5.2.1 Executive Order 11593, Protection and Enhancement of the Cultural Environment, May 13, 1971

Executive Order 11593 outlines the responsibilities of Federal agencies to consider effects to historic properties in consultation with

the Advisory Council on Historic Preservation where a Federal undertaking may adversely affect a property. Agencies are also to

preserve, rehabilitate, and restore NR-listed historic properties. Agencies are encouraged to avoid, or at least mitigate, an adverse

effect on listed properties. The executive order furthers the purpose and policies associated with the National Environmental Policy

Act of 1969; the National Historic Preservation Act of 1966; the Historic Sites Act of 1935 and the Antiquities Act of 1906.

The Corps objective would be to avoid effects to cultural properties and make, at minimum, a no adverse effect finding as

understood under NHPA. The Corps would consult with the Advisory Council on Historic Preservation as well as its other consulting

parties concerning adverse effects to historic properties that could result from the DMMP/EIS.

5.2.2 Executive Order 11988, Floodplain Management Guidelines, May 24, 1977

This order outlines the responsibilities of Federal agencies in the role of floodplain management. Each agency shall evaluate the

potential effects of actions on floodplains and should avoid undertaking actions that directly or indirectly induce growth in the

floodplain or adversely affect natural floodplain values. Alternatives considered in this DMMP/EIS include in-water and upland

disposal, levee raise (requiring roadway modifications), and beneficial uses for dredged material. In-water disposal and the levee

raise/roadway modifications are not anticipated to have any impact to the 100-year floodplain or water surface elevation. The area

designed for permanent disposal at the Joso site is not located in the 100-year floodplain. The temporary storage area for dredged

material (to be used for dewatering) would encroach on the 100-year floodplain and there would be minor, short-term impacts to the

floodplain but it is not expected to change the water surface elevation. Beneficial uses of dredged material are not anticipated to

present significant impacts to the floodplain areas but will need to be analyzed on a case-by-case basis. Woody riparian habitat

development would occur in the 100-year floodplain, but is not expected to change the water surface elevation.

5.2.3 Executive Order 11990, Protection of Wetlands

Executive Order 11990 encourages Federal agencies to take actions to minimize the destruction, loss, or degradation of wetlands,

and to preserve and enhance the natural and beneficial values of wetlands when undertaking Federal activities and programs.

Minor, short-term, indirect impacts to wetlands adjacent to the levees or roadways could occur during construction of improvements.

Upland disposal at Joso is anticipated to have minor, indirect impacts to two southwestern parcels resulting from unloading of

dredged material. Beneficial uses are expected to generally affect wetland resources in a positive manner by using dredged material

for enhancement or creation of aquatic and wildlife habitat. It has been the goal of the Corps to avoid or minimize wetland impacts in

the study area for all alternatives considered in this DMMP/EIS.

5.2.4 Executive Order 12898 - Federal Actions to Address Environmental Justice in Minority Populations

and Low-Income Populations, February 11, 1994

Executive Order 12898 requires Federal agencies to consider and address environmental justice by identifying and assessing

whether agency actions may have disproportionately high and adverse human health or environmental effects on minority or

low-income populations. Disproportionately high and adverse effects are those effects that are predominantly borne by minority

and/or low-income populations and are appreciably more severe or greater in magnitude than the effects on non-minority or non-low

income populations.

This DMMP/EIS programmatically considers activities related to long-term management of the lower Snake River and McNary

reservoirs. In particular, dredging, dredged material management, and maintenance of flood flow conveyance activities are

contemplated in this plan.

The effects of the categories of actions contemplated in this DMMP/EIS are not anticipated to be borne predominantly by any

particular low- income or minority group such that the effects would be considered disproportionately high and adverse with respect

to low-income or minority populations. Dredging would occur within the established navigation channel and at specific recreation

areas and Corps HMU irrigation intakes. In-water and upland placement of dredged materials are considered in this plan; the effects

from either management approach are not anticipated to specifically or disproportionately affect any particular low- income or

minority population. Maintenance of flood flow conveyance would involve raising levees in the Lewiston area and is similarly not

expected to disproportionately affect any particular demographic group.

5.2.5 Executive Order 13007, Native American Sacred Sites, May 24, 1996

Executive Order 13007 directs Federal agencies to accommodate access to and ceremonial use of Indian sacred sites by Indian

religious practitioners. Agencies are to avoid adversely affecting the physical integrity of such sacred sites and to maintain the

confidentiality of sacred sites when appropriate. The act encourages government-to-government consultation with tribes concerning

sacred sites. Some sacred sites may qualify as historic properties und er the NHPA. The Corps welcomes discussion of concerns or

issues involving sacred sites and invites tribes to bring concerns as a part of the consultation process for the DMMP/EIS. The few

that have been identified do not lie within the DMMP/EIS study area.

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5.3 EXECUTIVE MEMORANDA

5.3.1 Council on Environmental Quality Memorandum, August 11, 1990,

Analysis of Impacts on Prime or Unique Agricultural Lands in Implementing NEPA

The Council on Environmental Quality Memorandum establishes criteria to identify and consider the adverse effects of Federal

programs on the preservation of prime and unique farmland, to consider alternative actions, as appropriate, that could lessen

adverse effects, and to ensure Federal programs are consistent with all state and local programs for the protection of farmland.

The proposed action was determined not to have an impact on prime or unique agricultural lands.

5.4 STATE STATUTES

The CEQ regulations (40 CFR 1506.2) require consideration of the consistency of a proposed action with approved state and local

plans and laws. Dredging activities proposed in this DMMP/EIS have been evaluated with regard to applicable state statutes and

regulations.

Compliance issues have been considered and addressed where applicable to the subject dredging activities. A few statutes

considered include, but are not limited to:

Stream Channel Alteration Permit (Idaho)

Removal-Fill Law (Oregon)

Hydraulic Project Approval (Washington)

Shoreline Management Act (Washington)

Section 6

Coordination, Consultation, and Public Involvement

In November 2001 the Corps of Engineers distributed the Draft DMMP/EIS for the Lower Snake River and McNary Reservoirs for

public review. The public comment period lasted through January 7, 2002. Twenty-six comment documents (letters and e- mails)

were received. The Corps also conducted two public meetings in December 2001 (in Pasco, Washington, on December 12th and

Lewiston, Idaho, on December 13th) to receive comments on the DMMP/EIS. The Corps considered all public comments received

throughout the planning process. In addition to the opportunities to comment on the DMMP/EIS, the Corps has undertaken efforts

throughout the planning process to coordinate and consult with agencies, affected tribal groups, and interested members of the

public. A brief discussion of these efforts is provided below.

6.1 SCOPING

The Notice of Intent to prepare a draft Environmental Impact Statement (DEIS) for the proposed DMMS was published on August 5,

1998. In September 1998, the Corps held two regional public scoping meetings to allow the public and interested agencies to learn

about the purpose and scope of the Walla Walla District’s dredging program. Discussions included ways to reduce the need to

dredge for navigation, comparing dredging and disposal methods, identifying and evaluating disposal sites, and the Corps’ intent to

prepare a programmatic DMMP and EIS.

These public scoping meetings were held in Richland, Washington, and in Lewiston, Idaho. Meeting participants represented ports,

Federal and state governmental agencies, local businesses, farming, and a member of Congress. The Corps used the input and

concerns from the scoping meetings to help define and refine the scope of the plan, alternatives, and environmental documentation.

The Corps received input that included concerns/ issues regarding dredging and disposal management, alternatives to dredging,

and potential beneficial uses of dredged materials. Major issues or concerns identified included impacts to waterfowl and wildlife,

maintaining water quality, maintaining navigation, and planning for an annual dredging program. Some of the alternatives

mentioned were implementing erosion control and soil conservation measures to keep sediment from entering the rivers, installing

flow velocity devices, and annually drawing down the reservoirs to flush sediments and allow for dredging in the dry. Potential

beneficial uses identified include creating islands, fish and wildlife habitat, new land for port development, and beaches.

6.2 MEETINGS WITH RESOURCE AGENCIES

Following a preliminary evaluation of alternatives, the Corps held a meeting in August 1999 with representatives of natural resource

management, regulatory agencies, and tribal interests. The purpose of this meeting was to present the range of alternatives to be

evaluated in the DEIS, including the recommended plan, to the agency representatives and receive their input on the alternatives

and their evaluation of the DEIS.

In July 2000, the Corps hosted the first meeting of the LSMG. Representatives from Federal and state agencies, ports, and tribes

attended. At the meeting, the Corps presented an overview of the DMMP and a projected schedule for its completion. The Corps

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also presented a summary of the results of Dr. Bennett’s studies on the effects of dredging on aquatic resources.

In February 2001, the Corps hosted a second meeting of the LSMG. The purpose of the meeting was to continue discussions of

dredging and dredged material disposal activities in the navigable waters within the boundaries of the Walla Walla District. The

meeting included a presentation by Dr. Bennett, PhD, University of Idaho, on the results of his dredging studies in the lower Snake

River, an overview of the National and Regional Dredging Teams, a status report on the DMMP, and a status report on the dredging

framework for the lower Snake and Clearwater Rivers and McNary reservoir.

The LSMG met again in December 2001 to discuss the status of the DMMP process, beneficial uses of dredged material, the

proposed woody riparian habitat program, the proposed 2002-2003 maintenance dredging, and the dredged material evaluation

framework.

6.3 ENDANGERED SPECIES ACT CONSULTATION

To fulfill the requirements of the ES A, the Corps conducted consultation with both the USFWS and the NMFS. The Corps has

prepared BAs discussing the impacts of the proposed project on listed species that may be in the project area. The Corps sent the

BA for terrestrial species and non-anadromous fish species to USFWS with a request for informal consultation. The Corps sent the

BA for anadromous fish species to NMFS with a request for formal consultation. The Corps has received concurrence from USFWS

regarding the findings presented in the BA (and summarized in this DMMP/EIS). The NMFS determined that the proposed actions

would not jeopardize the continued existence of listed fish species, contingent on the Reasonable and Prudent Measures presented

in their Biological Opinion. See Appendix F and G.

6.4 TRIBAL CONSULTATION

The Corps is also following a separate consultation process with the tribes. Indian treaties, Federal statutes, executive orders,

national policies, and court cases have collectively and over time caused changes in how these relationships are exercised. Federal

agencies are to consult and coordinate with American Indian tribes and traditional communities about their actions. In facilitating this

process, the Corps seeks to provide meaningful and timely opportunities for tribes to comment on agency policies that may have

significant or unique effects on tribal interests.

6.4.1 Laws and Statutes Relating to Tribal Interests

There are many Federal laws, executive orders, policy directives, and Federal regulations that address responsibilities of the

executive branch agencies regarding tribal interests. Collectively, these form the basis of how consultation is conducted and have

had a profound impact on Federal-tribal relations. Examples of the statutes specifically discussing tribal interests are NHPA,

Archeological Resources Protection Act, NAGPRA, and AIRFA. Summaries of these statutes can be found in section 5 of this report.

Specifically, places of cultural and religious significance to tribes are to be considered by Federal agencies in policy and project

planning. The Corps is increasingly engaging and involving tribes in collaborative processes designed to facilitate the exchange of

information and to effectively address effects of Federal actions and policies on tribal interests and rights.

6.4.2 U.S. Army Corps of Engineers Policy Guidance and American Indian Tribes

In February 1998, Lt. General Joe N. Ballard, Chief of Engineering, published a Memorandum for Commanders, Major Subordinate

Commands and Distric t Commands: Policy Guidance Letter No. 57, Indian Sovereignty and Government-to-Government Relations

with Indian Tribes. Portions of that letter are quoted below:

"1. Our Nation has long recognized the sovereign status of Indian tribes. The United States Constitution specifically

addresses Indian sovereignty by classing Indian treaties among the "supreme Law of the land," and establishes Indian

affairs as a unique focus of Federal concern. Principles outlined in the Constitution and treaties, as well as those

established by Federal laws, regulations and Executive Orders, continue to guide our national policy towards Indian

Nations.

2. On 29 April 1994, President Clinton reaffirmed the United States’ "unique legal relationship with Native American tribal

governments." In recognition of the special considerations due to tribal interests, the President directed Federal agencies

to operate within a government-to-government relationship with federally recognized Indian tribes; consult, to the

greatest extent practicable and permitted by law, with Indian tribal governments; assess the impact of agency activities

on tribal trust resources and assure that tribal interests are considered before the activities are undertaken; and remove

procedural impediments to working directly with tribal governments on activities that affect trust property or governmental

rights of the tribes...."

"3. ....I want to ensure that all Corps Commands adhere to principles of respect for Indian tribal governments and honor

our Nation’s trust responsibility. To this end I have enclosed U.S. Army Corps of Engineers Tribal Policy Principles, for

use as interim guidance until more detailed statements are developed. These Principles have been developed with the

Office of the Assistant Secretary of the Army (Civil Works) and are consistent with the President’s goals and

objectives...."

"U.S. ARMY CORPS OF ENGINEERS

TRIBAL POLICY PRINCIPLES

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TRIBAL SOVEREIGNTY - The U.S. Army Corps of Engineers recognizes that Tribal governments are sovereign ent ities,

with rights to set their own priorities, develop and manage Tribal and trust resources, and be involved in Federal

decisions or activities which have the potential to affect these rights. Tribes retain inherent powers of self-government.

TRUST RESPONSIBILITY - The U.S. Army Corps of Engineers will work to meet trust obligations, protect trust

resources, and obtain Tribal views of trust and treaty responsibilities or actions related to the Corps, in accordance with

provisions of treaties, laws and Executive Orders as well as principles lodged in the Constitution of the United States.

GOVERNMENT-TO-GOVERNMENT RELATIONS - The U.S. Army Corps of Engineers will ensure that Tribal

Chairs/Leaders meet with Corps Commanders/Leaders and recognize that, as governments, tribes have the right to be

treated with appropriate respect and dignity, in accordance with principles of self-determination.

PRE-DECISIONAL AND HONEST CONSULTATION - The U.S. Army Corps of Engineers will reach out, through

designated points of contact, to involve tribes in collaborative processes designed to ensure information exchange,

consideration of disparate viewpoints before and during decision making, and utilize fair and impartial dispute resolution

mechanisms.

SELF RELIANCE, CAPACITY BUILDING, AND GROWTH - The U.S. Army Corps of Engineers will search for ways to

involve Tribes in programs, projects and other activities that build economic capacity and foster abilities to manage Tribal

resources while preserving cultural identities.

NATURAL AND CULTURAL RESOURCES - The U.S. Army Corps of Engineers will act to fulfill obligations to preserve

and protect trust resources, comply with the Native American Graves Protection and Repatriation Act, and ensure

reasonable access to sacred sites in accordance with published and easily accessible guidance."

In August 2001, Clifton P. Jackson, Jr., Executive Assistant for the Commander, published CENWD-NA Regulation No. 5-1-1,

Management Native American Policy for the Northwestern Division, covering the policy, responsibilities, and implementation of the

U. S. Army Corps of Engineers Tribal Policy Principles. This regulation applies to all Northwestern Division commands having

responsibility for Civil Works, military, and Hazardous, Toxic, and Radioactive Waste functions. The policy and responsibilities

associated with this regulation are reproduced here:

"POLICY. It is the policy of the Northwestern Division to apply the USACE Tribal Policy Principles into all division

activities that may impact any federally recognized Indian Tribe. In those activities where consultation is warranted, it is

the policy of the Northwestern Division to consult on a government-to-government level consistent with guidance found in

White House Memorandum, Government-to-Government Relations, 29 April 1994; CECW PLG 57, Indian Sovereignty

and Government-to-Government Relations with Indian Tribes, 18 February 1998, and USACE Tribal Policy Principles; DA

Pamphlet 200-4, Cultural Resources Management, Appendix G, Guidelines for Army Consultation with Native Americans,

30 October 1997; DOD American Indian and Alaska Native Policy, 20 October 1998; and Executive Order 13175,

Consultation and Coordination with Indian Tribal Governments, 6 November 2000.

RESPONSIBILITIES.

a. Division Commander Responsibilities.

(1) The Division Commander is responsible for integrating the USACE Tribal Policy Principles into all division

activities that may impact any federally recognized Indian Tribe.

(2) The Division Commander will provide regional interface with Tribal governments for activities or issues involving

multiple districts and refer appropriate actions to the affected district(s).

(3) The Division Commander will develop a Tribal account management plan to guide business development and

outreach opportunities that promote USACE capabilities while fostering Tribal self reliance, capacity building and growth.

(4) The Division Commander will formally designate and train a Native American Coordinator(s) with primary or

collateral duties to provide quality assurance of district Native American programs and activities.

b. District Commander Responsibilities.

(1) The District commander is responsible for integrating the USACE Tribal Policy Principles into all district activities

that may impact any federally recognized Indian Tribe.

(a) TRIBAL SOVEREIGNTY - The district will affirm the sovereign status of Tribal governments, and work to

develop and enhance a relationship which acknowledges the right of federally recognized Tribes to set their own

priorities, develop and manage tribal trust resources.

(b) TRUST RESPONSIBILITY - The district will work to meet Tribal needs related to district activities and work to

protect trust resources.

(c) GOVERNMENT-TO-GOVERNMENT RELATIONS - The District Commanders and their designated staff

representatives shall meet with Tribal governments at the government-to-government level and observe tribal protocols

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and standards of dignity."

(d) PRE-DECISIONAL AND HONEST CONSULTATION - "Commanders and designated staff shall consult with

Tribal governments following the general concepts of the Guidelines for Army Consultation with Native Americans and

DOD American Indian and Alaska Native Policy.

(e) SELF-RELIANCE, CAPACITY BUILDING, AND GROWTH - The district will actively promote USACE

capabilities, business development and outreach opportunities with Tribes. The district will involve Tribes in district

programs that foster self-reliance, build economic capacity and growth such as training, cultural and natural resources,

recreation, watershed planning, environmental restoration, emergency management and contracting opportunities.

(f) NATURAL AND CULTURAL RESOURCES - Consistent with procedures set forth in applicable federal laws,

regulations and policies, the district will proactively work to preserve and protect natural and cultural trust resources,

establish Native American Graves Protection and Repatriation Act (NAGPRA) protocols and procedures; and allow

reasonable access to sacred sites.

(2) The District Commander will formally designate and train a Native American Coordinator with primary or

collateral duties to assist the Commander and other functional staff elements in ensuring that Tribal policy principles and

consultation are integrated into all district activities. The District Commander shall ensure Native American issues,

activities and contacts with Tribal governments are coordinated with the Native American Coordinator.

c. Servicing District. Coordination of Native American activities will be the responsibility of the servicing district consistent

with established civil works, regulatory and military boundaries."

6.4.3 Government-to-Government Consultation Status

The Corps has made a number of efforts to inform affected tribes of the DMMP/EIS and invite their participation. These have

included invitations to participate in the multi-agency resource meeting in August 1999 and the LSMG meeting in July 2000. Tribes

were mailed preliminary draft copies of the DMMP/EIS Chapters 1 and 2 in June 2000 and a draft cultural resources appendix in

October 2000 for technical staff reviews. Specific project information and evaluation along with the Feasibility Study and its

appendices on Cultural Resources and Tribal Consultation and Coordination, which are incorporated by reference, were included in

the DMMP/EIS. To reduce duplication of information, the appendix on Cultural Resources was not published with the Final

DMMP/EIS. A presentation was given to the Payos Kuus Cuukwe cultural resources cooperating group in October 2000 describing

the DMMP and EIS alternatives. Similar presentations were given during meetings hosted by representatives of the Confederated

Tribes of the Umatilla Indian Reservation in December 2000, the Confederated Tribes of the Colville Reservation in February 2001,

and the Nez Perce Tribe in April 2001. Those informational meetings were intended to develop technical staff understanding and

elicit comments.

The Corps is conducting formal consultation meetings with affected tribes to discuss pertinent aspects of the DMMP. The Corps will

complete consultation prior to a final decision and issuance of a Record of Decision.

6.5 PUBLIC REVIEW

As noted above, the Draft DMMP/EIS was distributed for public review and comment. A notice of availability was published in the

Fed Register on November 23, 2001. Distribution included local and state governments, local and regional business interests, public

libraries in the study area, affected tribes, Federal regulatory agencies, and members of the general public. All public comments

received were considered and have been addressed in the Final DMMP/EIS.

Appendix O presents the documents that were received during the public comment period. In total, 26 comment letters and e- mails

were received from local, state, and federal agencies, tribes, organizations (including environmental and transportation groups), and

citizens. Appendix O also presents the Corps’ responses to the public comments. Where appropriate, the Corps reconsidered its

planning process and analyses and modified its documentation in response to public comments.

This Final DMMP/EIS has been distributed to the public and at least 30 days after the Notice of Availability of the Final is published

in the Federal Register, the Corps plans to sign a Record of Decision for this DMMP/EIS.

Section 7

List of Preparers

The Corps was assisted in preparing this DMMP/EIS by HDR Engineering, Inc., a consulting firm under contract to the Corps. HDR

was assisted by Northwest Economic Associates, Inc., and Northwest Archaeological Associates, Inc. Contributions by individual

preparers were subject to revision during the internal review process. The Corps also contracted with David H. Bennett, Ph.D., for

input to this DMMP/EIS.

Individuals responsible for preparing this DMMP/EIS are listed in tables 7-1 (Corps) and 7-2 (Consultant Team). Because of the

number of people involved in coordinating this study, the information presented in these tables is limited to the names,

education/years of experience, experience and expertise, and general roles these individuals had in developing the DMMP/EIS.

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Section 8 - Distribution List

The Corps has distributed the Executive Summary of the draft DMMP/EIS, the entire draft DMMP/EIS, or requested parts of the draft

DMMP/EIS to the following:

Section 9

Glossary and Acronyms/Abbreviations

9.1 GLOSSARY

This glossary defines terms that are found in this DMMP/EIS:

Anadromous Fish: Species of fish that hatch in fresh water, migrate to and mature in the ocean (salt water), and return upstream

to fresh water to spawn. Salmon, steelhead, sturgeon, and shad are examples.

Archaeological Resource: See cultural resource.

Authorized Project: A project established by the authority of the U.S. Congress for the specific purposes described in the

legislation (e.g., flood control, power generation, navigation, irrigation, recreation, fish and wildlife, etc.).

Buffer: Usually a natural area or open space used to divide two developed or developing areas.

Clamshell Dredging: Clamshell dredges use a bucket operated from a crane or derrick that is mounted on a barge or operated

from shore. Sediment removed by the bucket is usually placed on a barge for disposal to either an upland or in-water site. Dredged

material comes up virtually undisturbed, so clamshell dredges work well in silts or contaminated material, where water entrainment

is a problem.

Cubic Feet Per Second (cfs): A unit of measurement (English) that can be used to describe the flow rate or discharge of water.

One cfs is equal to 449 gallons per minute.

Cubic Meter Per Second (cms): A unit of measurement (SI) that can be used to describe the flow rate or discharge of water. One

cms is equal to 35.31 cfs.

Cultural Resource: Evidence of human occupation or activity that is important in the history, architecture, or archaeology of a

community or region.

Diadromous: Truly migratory fishes that migrate between the sea and fresh water. Included among this group are anadromous

fishes (those that spend most of their life in the sea and migrate to fresh water to breed), catadromous fishes (those that spend

most of their life in fresh water and migrate to the sea to breed), and amphidromous fishes (those for which migration to the sea or

fresh water is not done for the purpose of breeding, but occurs regularly at some other definite stage of the life cycle) (Bond, 1979).

For example, white sturgeon have been known to exhibit both anadromous and amphidromous behavior but are often simply called

diadromous.

Dredged Material Management Plan (DMMP): The dredging and disposal plan that results from analyses conducted in the

Dredged Material Management Study.

Dredged Material Management Study (DMMS): An analysis of dredging and disposal alternatives that address cost, engineering,

and environmental factors to operate and maintain the navigation channel.

Dredging Template: A layout, diagram, or map showing the extent of the area required to be free from underwater hazards or

obstructions for purposes of navigation, recreation, and irrigation intake. If material has been deposited within the template, it would

require removal, usually by dredging. In the case of the navigation channel, the extent would be defined by the depth, bottom width,

and side slopes of the channel as well as advance maintenance measures and allowable overdepth if specified. In the case of a

boat landing or irrigation intake, the extent may be defined by the construction plans for the area. In the case of flow conveyance

dredging, the defined template may extend outside the limits of the navigation channel and, in some cases, down into original

riverbed material.

Easement: An interest or a privilege in land created by a provision in a deed or by an agreement that confers a right on the owner to

some profit, benefit, dominion, or lawful use out of or over the estate of another.

Ecosystem: Living and nonliving components of the environment that interact or function together.

Endangered Species: Any species of plant or animal defined through the Endangered Species Act as being in danger of extinction

throughout all or a significant portion of its range. Endangered Species are published in the Federal Register.

Fill: The placement, deposition, or stockpiling of sand, sediment, or other earth materials.

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Flow Rate: The volume of water passing a given point per unit of time. Flow rate is often measured in cubic feet per second

(English units) or cubic meters per second (SI units).

Habitat: The place or conditions where a plant or animal lives or can live. The plant or animal can be an individual organism, a

population, or a taxonomic group. In the present context, habitat refers to an area that provides some portion of the requirements for

the life history of a given species.

In-Water Disposal: The placement of dredged material along the riverbed in or adjacent to the navigation channel or in designated

in-water sites.

Juvenile: The early stage in the life cycle of anadromous fish when they migrate downstream to the ocean.

Levee: An earthen embankment/dike constructed to prevent a water source from overflowing onto an adjacent area.

Lockage: An act or the process of passing a vessel through a lock.

Locks: A chambered structure of a waterway closed off with gates for the purpose of raising or lowering the water level within the

chamber so ships can move along the waterway.

Minimum Operating Pool (MOP): The bottom 1 foot (0.3 meter) of the operating range for each reservoir. The reservoirs have an

operating range of 3 to 5 feet (0.9 to 1.5 meters).

Mitigation: The use of any or all of the following actions:

Avoiding the impact altogether by not taking a certain action or parts of an action.

Minimizing impacts by limiting the degree or magnitude of the action and its implementation.

Rectifying the impact by repairing, rehabilitating, or restoring the affected environment.

Reducing or eliminating the impact over time by preservation and maintenance operations during the life of the action.

Monitoring: A process of collecting information to evaluate if objectives and anticipated results of a management plan are being

realized or if implementation proceeds as planned.

National Ambient Air Quality Standards (NAAQS): Standards set by the Environmental Protection Agency that identify the limit of

concentrations of certain air pollutants that endanger public health or welfare.

Pool/Reservoir: A body of water impounded by a dam.

Project: The broad term covering the Federally constructed and maintained channels and structures on the Columbia and Snake

Rivers. A "Project" is a channel or facility constructed for variety of authorized purposes, such as, hydroelectric generation, flood

control, navigation, etc.

Reach: A section of river, usually defined by River Mile.

Resident Fish: Fish species that reside in fresh water throughout their lives.

Riparian: The area immediately adjacent to streams, ponds, lakes, and wetlands that directly contributes to the water quality and

habitat components of the water body. This may include areas that have high water tables and soils and vegetation that exhibit

characteristics of wetness, as well as upland areas immediately adjacent to the water body that directly contribute shade, nutrients,

cover, or debris, or that directly enhance water quality within the water body.

River Mile (RM): A consistent linear measurement from a particular defined place on a river. For the Columbia River, River Miles are

measured from the mouth of the river at the Pacific Ocean. For the Snake River, River Miles are measured from the confluence of

the Snake River with the Columbia River near Pasco, Washington.

Salmonids: Refers to fish of the family Salmonidae.

Spawning: The releasing and fertilizing of eggs by fish.

Species: A group of organisms that can interbreed in nature (a common gene pool that is biologically isolated from closely related

species) and is designated by an available and valid scientific name.

Standard Project Flood (SPF): An estimated or hypothetical flood that might be expected from the most severe combination of

meteorological and hydrological conditions that are considered reasonably characteristic of the geographical region involved,

excluding extraordinarily rare combinations.

Threatened Species: Plant or animal species likely to become an endangered species throughout all or a significant portion of their

range within the foreseeable future. Plant or animal identified and defined in accordance with the 1973 Endangered Species Act

and published in the Federal Register.

Upland: Any area that does not qualify as a wetland because the associated hydrologic regime is not sufficiently wet to elicit

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development of vegetation, soils, and/or hydrologic characteristics associated with wetlands.

Water Quality: The chemical, physical, and biological characteristics of water.

Wetlands: Areas inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, under normal

circumstances, a prevalence of vegetation typically adapted for life in saturated soil conditions. This does not include riparian areas,

rivers, streams, and lakes.

9.2 ACRONYMS/ABBREVIATIONS

The following acronyms used within this document are defined below:

APE Area of Potential Effect

ASTM American Society for Testing and Materials

BA Biological Assessment

BMP Best Management Practice

BNSF Burlington Northern and Santa Fe Railroad

Bonneville Bonneville Lock and Dam

B.P. before present

BPA Bonneville Power Administration

CAA Clean Air Act

CERCLA Comprehensive Environmental Response Compensation Liability Act

cfs cubic feet per second

cm centimeter

Corps U.S. Army Corps of Engineers, Walla Walla District

CPRR Camas Prairie Railroad

CRBG Columbia River Basalt Group

CWA Clean Water Act

dBA A-weighted decibels

DEIS Draft Environmental Impact Statement

DEQ Department of Environmental Quality

DMMP Dredged Material Management Plan

DMMS Dredged Material Management Study

DO dissolved oxygen

DWS domestic water supply

EC Engineering Circular

EDNA Environmental Designation for Noise Abatement

EFH Essential Fish Habitat

EIS Environmental Impact Statement

EPA U.S. Environmental Protection Agency

ER Engineering Regulation

ESA Endangered Species Act

ESC erosion sedimentation control

ESU Evolutionarily Significant Unit

FCRPS Federal Columbia River Power System

Feasibility Study Lower Snake River Juvenile Salmon Migration Feasibility Study

FY fiscal year

HMU Habitat Management Unit

HTRW Hazardous, Toxic, or Radioactive Waste

Ice Harbor Ice Harbor Lock and Dam

ITM Inland Testing Manual

km kilometer

Little Goose Little Goose Lock and Dam

Lower Granite Lower Granite Lock and Dam

Lower Monumental Lower Monumental Lock and Dam

LSMG Local Sediment Management Group

LSRFWCP Lower Snake River Fish and Wildlife Compensation Plan

m meter

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m3 cubic meter

m3sec cubic meters per second

McNary McNary Lock and Dam

MOP minimum operating pool

mg/L milligrams per liter

mm millimeter

m/s meters per second

msl mean sea level

NAAQS National Ambient Air Quality Standards

NEPA National Environmental Policy Act

NHPA National Historic Preservation Act

NR National Register

NRHP National Register of Historic Places

NMFS National Marine Fisheries Service

NTU nephelometric turbidity unit

NWI National Wetlands Inventory

NWR National Wildlife Refuge

ortho-P ortho-phosphate

PIT passive integrated transponder

PM particulate matter

ppm parts per million

RCRA Resource Conservation and Recovery Act

RDT Regional Dredging Team

RM River Mile

ROD Record of Decision

SHPO State Historic Preservation Office

SOR FEIS System Operational Review Final Environmental Impact Statement

SPF Standard Project Flood

SR State Route

TCP traditional cultural properties

TEQ toxic equivalency quotient

The Dalles The Dalles Lock and Dam

TMDL total maximum daily load

TP total phosphorus

TSS total suspended solids

UPRR Union Pacific Railroad

USACE U.S. Army Corps of Engineers

USDOE U.S. Department of Energy

USFWS U.S. Fish and Wildlife Service

USGS U.S. Geological Survey

WAC Washington Administrative Code

WDFW Washington Department of Fish and Wildlife

WES Waterways Experiment Station

YOY young of the year

Section 10

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List of Plates

Plate

1 Study Area

2 McNary Dam and Reservoir: RM 289 - 298

3 McNary Reservoir: RM 299 - 310

4 McNary Reservoir: RM 310 - 321

5 McNary Reservoir: RM 322 - 329

6 McNary Reservoir: RM 330 - 341

7 McNary Reservoir: RM 342 - 352

8 Ice Harbor Dam and Reservoir: RM 9 - 22

9 Ice Harbor Reservoir: RM 21 - 35

10 Lower Monumental Dam and Reservoir: RM 34 - 49

11 Lower Monumental Reservoir: RM 48 - 61

12 Little Goose Dam and Reservoir: RM 60 - 74

13 Little Goose Reservoir: RM 73 - 87

14 Little Goose Reservoir: RM 84 - 99

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15 Lower Granite Dam and Reservoir: RM 99 - 116

16 Lower Granite Reservoir: RM 114 - 128

17 Lower Granite Reservoir: RM 127 - 147

18 3-Foot Levee Raise

Appendix A - Hydrologic Analysis

Appendix B - Cost Estimates

Appendix C - Economic Analysis

Appendix D - Upland Disposal Conceptual Design

Appendix E - Levee Modification/Extension Analysis

Appendix F - Endangered Species Act Consultation for Anadromous Fish Species

Appendix G - Endangered Species Act Consultation for Non-Anadromous Fish and Terrestrial Species

Appendix H - Water and Sediment Quality

Appendix I - Section 404(b)(1) Evaluation

Appendix J - Dredged Material Evaluation Framework

Appendix K - Aquatic Resources

Appendix L - Cultural Resources (Deleted - Detailed Cultural Resources Information is Presented in this Final DMMP/EIS)

Appendix M - Monitoring Plan

Appendix N - Dredging Proposed for Winter 2002-2003

Appendix O - Response to Comments on the Draft DMMP/EIS

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