1. Thomas R. Payne & Associates Update on Flood Storage Fish Study Presented by Paul Schlenger, Bob Montgomery, Jim Shannon June 15, 2011

2. Overview of Presentation Introduction Update on Fish Study Analysis Components –Hydrology –Water Quality –Geomorphology –Fish Habitat Modeling (PHABSIM) –Fish Population Modeling (SHIRAZ) Next Steps Recommended Steps

3. Purpose of Fish Study To characterize the magnitude of potential impacts that a flood storage facility on the upper mainstem Chehalis River could have on anadromous salmon populations

4. Study Approach To use applicable existing and new data to characterize habitat conditions in the basin that contribute to salmon viability and would potentially be impacted by a dam –Hydrology and Hydraulics (water flow) –Water Quality (temperature) –Geomorphology (sediment transport)

5. Study Approach

6. Understanding of Dam Structure and Operations Structure or Operational Element Flood StorageMulti-Purpose Construction Complete2020 Structure Location2 miles south of Pe Ell (RM 108.3) Structure Height238 feet288 feet Reservoir Surface Area (full) 1,000 acres1,450 acres Fish Passage FacilitiesYes Sediment Transport Past Dam No Large Woody Debris Transport Past Dam No

7. Fish Study Status Fish Study Elements –Hydrology –Water Quality –Geomorphology –Fish Habitat Modeling (PHABSIM) in prep. –Fish Population Modeling (SHIRAZ) in prep.

8. Geomorphology Geomorphic Reaches Changes to Geomorphic Reaches from proposed flood storage facility

9. Geomorphic Reaches Geo- morphic ReachLocationConfinement Average GradientComments 1 Headwaters to RM 107.8 Confined1.05%Headwaters upstream of Pe Ell 2 RM 107.8 to RM 93.5 Moderately confined 0.25% Varies between confined and unconfined Includes Rainbow Falls 3 RM 93.5 to RM 88 Unconfined0.05% South Fork Chehalis enters at downstream end 4 RM 88 to RM 75.5 Locally confined 0.06% Newaukum River enters at downstream end Channel incised at downstream end 5 RM 75.5 to RM 61.7 Locally confined 0.03% No gravel or cobble transport; bedrock control at downstream end Incised channel mid-reach 6RM 61.7 to RM 33 Unconfined0.07%Very wide flood plain Black River enters mid-reach

10. Changes to Geomorphology Reduced peak flow Channel migration Bedload transport Reduced sediment and wood input

11. Estimated Changes to Geomorphology Reach 1 (upstream-most reach) –Inundated Reach 2 –Transport capacity 4 percent of existing. –Bedload transport 4 of 20 years vs. 12 of 20. –Sediment input 29 percent of existing. –Change? Aggradation and percent fines up. Reach 3 –Similar to Reach 2 but also channel migration patterns may change. Peak flow vs. aggradation?

12. Estimated Changes to Geomorphology Reach 4 and 5 –Transport capacity 65 percent of existing. –Sediment input 75 percent of existing. –Change? Aggradation and percent fines change relatively small. Reach 6 (downstream-most reach) –Changes muted because downstream of bedrock control grade.

13. Fish Habitat Modeling Using PHABSIM PHABSIM = Physical Habitat Simulation PHABSIM is a subcomponent of IFIM (Instream Flow Incremental Methodology) PHABSIM and IFIM were developed as aids to instream flow decision-making PHABSIM predicts changes in habitat availability with changes in flow

14. PHABSIM Mesohabitat survey Six reaches Ten study sites 71 transects Reviewed and agreed upon with WDFW and Ecology Measured depth, velocity, substrate, and cover along transects

15. Mesohabitat Results Chehalis River Reaches Habitat Type Pe Ell to Elk Creek (RM 106.5 to 100.2) Elk Creek to South Fork (RM 100.2 to 88.0) South Fork to Newaukum (RM 88.0 to 75.3) Pool34.361.670.6 Glide22.311.2 Run28.318.815.1 Low Gradient Riffle14.97.53.0 High Gradient Riffle0.2 ----- Cascade-----0.2----- Other-----0.50.1 Habitat Type Newaukum to Skookumchuck (RM 75.3 to 66.8) Skookumchuck to Black River (RM 66.8 to 47.0) Black River to Porter (RM 47.0 to 33.3) Pool99.270.370.0 Glide0.213.39.4 Run0.611.414.6 Low Gradient Riffle-----5.06.0 High Gradient Riffle----- Cascade----- Other-----

16. PHABSIM-Flow and Life Stage Maximum Study Reach Flow (cfs) at Maximum Usable Habitat (80% Range) Chinook SpawningChinook Juvenile Steelhead Spawning Steelhead Juvenile Coho Spawning Dam Site to Pe Ell 160 (90 to 240) 130 (60 to 350) 190 (130 to 290) 170 (70 to 350) 220 (130 to 350) Pe Ell to Elk Creek 260 (120 to 400) 200 (120 to 400) 350 (180 to 500) 240 (140 to 450) 350 (220 to 600) Elk Creek to South Fork 650 (400 to 900) 300 (150 to 700) 400 (200 to 600) 400 (200 to 800) 400 (250 to 650) South Fork to Newaukum River 950 (350 to 1,400) 500 (250 to 850) 350 (200 to 600) 600 (300 to 1,000) 350 (150 to 750) Skookumchuck to Black River 2,200 (1,200 to 4,000) 1,000 (350 to 2,200) 650 (300 to 1,600) 1,400 (500 to 2,600) 650 (250 to 1,600) Black River to Porter 2,200 (1,200 to 4,000) 1,000 (350 to 2,200) 650 (300 to 1,600) 1,400 (500 to 2,600) 650 (250 to 1,600)

17. PHABSIM

18. Used results in SHIRAZ to determine spawning and rearing areas. Results must be put into context. Other variables (i.e. water quality) Looking at peaks oversimplifies results (i.e. maximum flow may not exist in a reach) Usable habitat can be the same at two flows.

19. Fish Population Modeling Using SHIRAZ Microsoft Excel-based model to relate habitat conditions to salmon production –Capacity –Productivity User-defined inputs to build the model, i.e., a transparent model Allows for year-to-year changes in habitat conditions (as well as marine survival, harvest, and hatcheries, if desired)

20. Relies Upon Beverton-Holt Stock Recruitment Model

21. SHIRAZ Inputs Species data Define assessment reaches Populate model with data to characterize habitat conditions in each reach Establish relationships, i.e., functional linkages, between habitat conditions and salmon survival Future condition scenarios

22. Species Data Species presence and distribution –Coho, spring Chinook, winter steelhead Life history –Freshwater lifestages –Age of outmigration –Age of return migration Species periodicity Population numbers in the mainstem

23. Assessment Reaches

24. Habitat Conditions Capacity –Spawning area (flow dependent) –Rearing area (flow dependent) Productivity –Flow –Water temperature –Fine sediment in redds

25. Functional Linkages

26. Future Condition Scenarios Flood Storage Facility –Natural flows past dam when in non-flood conditions –Following flood, downstream flows increased by reservoir draining Multi-Purpose Facility –Controlled flows when in non-flood conditions, including potential to augment low flows Use studies to inform habitat condition changes

27. SHIRAZ Outputs Number of population alive by lifestage & area Life-cycle productivity

28. Next Steps Complete PHABSIM data collection and analysis Continue to build SHIRAZ models Reporting Data Transfer Workshop

29. Recommended Steps Collect more data on habitat conditions in proposed inundation area and representative portions of tributaries that would not be inundated Incorporate projected changes in basin hydrology associated with climate change Aerial photo interpretation of the growth of gravel bars Cross-section surveys at the same location as previous surveys, such as the FEMA surveys from the early 1980s – dual purpose to help in the sediment budget analysis and support updating the HEC-RAS model

30. Recommended Steps (continued) Investigate fish passage options for a dam Investigate sediment transport and/or large woody debris transport options for passing material past a dam Comprehensively identify opportunities to enhance habitat to improve fish population resilience in basin whether dam constructed or major floods encountered