Boundary Hydroelectric Project (FERC No. 2144) Draft Biological Assessment Seattle City Light March 2010 DRAFT BIOLOGICAL ASSESSMENT TABLE OF CONTENTS 1 Introduction ........................................................................................................................... 1 1.1. Background ..................................................................................................... 1 1.2. Project Purpose ................................................................................................ 3 2 Existing Conditions ............................................................................................................... 3 2.1. Site Description ............................................................................................... 3 2.2. Action Areas .................................................................................................... 8 2.2.1. Aquatic Action Area .........................................................................................8 2.2.2. Terrestrial Action Area .....................................................................................8 2.3. Aquatic Species ............................................................................................... 9 2.3.1. Reservoir and Delta Habitat Conditions .........................................................17 2.3.2. Habitat Connectivity .......................................................................................27 2.3.3. Water Quality .................................................................................................36 2.3.4. Ecosystem Functions ......................................................................................39 2.4. Terrestrial Species ......................................................................................... 47 2.4.1. Canada Lynx ...................................................................................................49 2.4.2. Woodland Caribou .........................................................................................50 2.4.3. Grizzly Bear ...................................................................................................51 3 Description of Actions......................................................................................................... 52 3.1. Proposed Project Operation ........................................................................... 52 3.2. Conservation Measures Affecting Aquatic Species ...................................... 53 3.2.1. Gravel Augmentation Below Box Canyon Dam ............................................54 3.2.2. Channel Modifications for Mainstem Trapping Pools at Project RM 30.3 ....56 3.2.3. Mainstem Large Woody Debris at Tributary Deltas ......................................57 3.2.4. Boundary Reservoir Fish Community Monitoring and Evaluation of Salmonid Predation at Select Tributary Deltas ..............................................59 3.2.5. Upstream Fish Passage ...................................................................................60 3.2.6. Reduction of Project Related Entrainment Mortality .....................................62 3.2.7. Tributary Non-native Trout Suppression and Eradication .............................63 3.2.8. Riparian Improvement and Stream Channel Enhancement in Sullivan Creek RM 0.00 to RM 0.54 ......................................................................................65 3.2.9. Stream and Riparian Improvements in Sullivan Creek from RM 2.30 to 3.0 and North Fork Sullivan Creek ......................................................................67 3.2.10. LWD Placement and Road Improvements in Sullivan Creek and Selected Tributaries Upstream of the Confluence with Outlet Creek ...........................69 3.2.11. Culvert Replacements and LWD Placement in Tributaries to Boundary Reservoir ........................................................................................................71 3.2.12. Riparian Planting, Culvert Replacement and Channel Reconstruction in Linton Creek RM 0.00 to RM 0.24 ................................................................72 3.2.13. Riparian and Channel Improvements in Sweet Creek RM 0.0 to RM 0.6 .....73 Boundary Hydroelectric Project Seattle City Light FERC No. 2144 i March 2010 DRAFT BIOLOGICAL ASSESSMENT 3.2.14. Habitat Improvement in Tier-2 Tributaries to Boundary Reservoir ...............76 3.2.15. Closure and Restoration of Sullivan Creek Dispersed Recreation Sites ........77 3.2.16. Mill Pond Dam Site Monitoring and Maintenance ........................................78 3.2.17. Native Salmonid Conservation Program ........................................................79 3.2.18. Recreational Fish Stocking Program ..............................................................80 3.2.19. Total Dissolved Gas .......................................................................................81 3.2.20. Operations ......................................................................................................82 3.3. Conservation Measures Affecting Terrestrial Species .................................. 83 4 Effects of Action .................................................................................................................. 83 4.1. Aquatic Species ............................................................................................. 83 4.1.1. Direct Effects ..................................................................................................83 4.1.2. Environmental Baseline and Cumulative Effects ...........................................86 4.2. Terrestrial Species ......................................................................................... 89 4.2.1. Canada Lynx ...................................................................................................90 4.2.2. Woodland Caribou .........................................................................................91 4.2.3. Grizzly Bear ...................................................................................................91 5 Conclusions .......................................................................................................................... 92 5.1. Aquatic Species ............................................................................................. 92 5.2. Terrestrial Species ......................................................................................... 94 6 References ............................................................................................................................ 95 Boundary Hydroelectric Project Seattle City Light FERC No. 2144 ii March 2010 DRAFT BIOLOGICAL ASSESSMENT List of Tables Table 1.0-1. Threatened and Endangered species in the Boundary Project Action Area addressed in this BA. ...........................................................................................................1 Table 2.3-1. Threatened fish species that occur in the vicinity of the Boundary Hydroelectric Project. ........................................................................................................10 Table 2.3-2. Descriptive statistics for tributaries to Boundary Reservoir. ....................................12 Table 2.3-3. Observations of bull trout in Boundary Reservoir, Boundary Dam tailrace, and tributaries to Boundary Reservoir, 1980 - 2009. .........................................................13 Table 2.3-4. List of tributaries, their calculated Habitat Suitability Indices, and their relative ranking for generic “salmonid” adult, juvenile, and fry life stages in the tributary delta areas of Boundary Reservoir derived from the Hickman and Raleigh (1982) riverine model. .......................................................................................................24 Table 2.3-5. Boundary Reservoir average monthly temperature values, their associated suitability, and final reservoir Habitat Suitability Index using Hickman and Raleigh’s (1982) lacustrine model. ....................................................................................24 Table 2.3-6. Estimated mortality through Boundary Dam for different pathways and fish size. ....................................................................................................................................29 Table 2.3-7. Summary of large woody debris collected at the Boundary Dam during 2007 and 2008. ............................................................................................................................43 Table 2.4-1. Federally-listed Threatened and Endangered terrestrial species that may occur in the Project vicinity. ........................................................................................................49 Table 3.2-1. Pools proposed for modification in trapping and stranding Region 10 (“Cobble Sisters”). .............................................................................................................57 Table 3.2-2. Relationship between fish size and estimated turbine mortality at Boundary Dam. ...................................................................................................................................63 Table 3.2-3. Boundary watershed waterbodies identified for suppression or eradication activities. ............................................................................................................................64 Table 5.1-1. Summary diagnostics matrix of effects of the proposed conservation