thomas r. payne & associates update on flood storage fish study presented by paul schlenger, bob...
TRANSCRIPT
Thomas R. Payne & Associates
Update on Flood Storage Fish Study
Presented by
Paul Schlenger, Bob Montgomery, Jim Shannon
June 15, 2011
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
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
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)
Study Approach
Understanding of Dam Structure and Operations
Structure or Operational Element
Flood Storage Multi-Purpose
Construction Complete 2020 2020
Structure Location 2 miles south of Pe Ell (RM 108.3)
2 miles south of Pe Ell (RM 108.3)
Structure Height 238 feet 288 feet
Reservoir Surface Area (full)
1,000 acres 1,450 acres
Fish Passage Facilities Yes Yes
Sediment Transport Past Dam
No No
Large Woody Debris Transport Past Dam
No No
Fish Study Status
• Fish Study Elements– Hydrology – Water Quality – Geomorphology – Fish Habitat Modeling (PHABSIM) in prep.– Fish Population Modeling (SHIRAZ) in prep.
Geomorphology
•Geomorphic Reaches•Changes to Geomorphic Reaches from proposed flood storage facility
Geomorphic ReachesGeo-
morphic Reach Location Confinement
Average Gradient Comments
1 Headwaters to RM 107.8
Confined 1.05% Headwaters upstream of Pe Ell
2 RM 107.8 to RM 93.5
Moderately confined
0.25% Varies between confined and unconfinedIncludes Rainbow Falls
3 RM 93.5 to RM 88
Unconfined 0.05% 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 end5 RM 75.5 to
RM 61.7Locally
confined0.03% No gravel or cobble transport; bedrock
control at downstream endIncised channel
mid-reach 6 RM 61.7 to
RM 33Unconfined 0.07% Very wide flood plain
Black River enters mid-reach
Changes to Geomorphology
•Reduced peak flow•Channel migration•Bedload transport
•Reduced sediment and wood input
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?
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.
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
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
Mesohabitat ResultsChehalis River Reaches
Habitat TypePe 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)
Pool 34.3 61.6 70.6
Glide 22.3 11.2 11.2
Run 28.3 18.8 15.1
Low Gradient Riffle 14.9 7.5 3.0
High Gradient Riffle 0.2 0.2 -----
Cascade ----- 0.2 -----
Other ----- 0.5 0.1
Habitat Type
Newaukumto Skookumchuck(RM 75.3 to 66.8)
Skookumchuck toBlack River
(RM 66.8 to 47.0)Black River to Porter
(RM 47.0 to 33.3)
Pool 99.2 70.3 70.0
Glide 0.2 13.3 9.4
Run 0.6 11.4 14.6
Low Gradient Riffle ----- 5.0 6.0
High Gradient Riffle ----- ----- -----
Cascade ----- ----- -----
Other ----- ----- -----
PHABSIM-Flow and Life Stage Maximum
Study Reach
Flow (cfs) at Maximum Usable Habitat(80% Range)
Chinook Spawning Chinook Juvenile
Steelhead Spawning
Steelhead Juvenile
Coho Spawning
Dam Siteto Pe Ell
160(90 to 240)
130(60 to 350)
190(130 to 290)
170(70 to 350)
220(130 to 350)
Pe Ellto Elk Creek
260(120 to 400)
200(120 to 400)
350(180 to 500)
240(140 to 450)
350(220 to 600)
Elk Creekto 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)
PHABSIM
PHABSIM•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.
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)
Shiraz
Productivity Capacity
Survival
Habitat
Relies Upon Beverton-Holt Stock Recruitment Model
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
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
Assessment Reaches
Habitat Conditions
• Capacity– Spawning area (flow dependent)– Rearing area (flow dependent)
• Productivity– Flow– Water temperature– Fine sediment in redds
Functional Linkages
0 2 4 6 8 10 12 14 16 18 200%
20%
40%
60%
80%
100%
Water Temperature During Egg Incubation(Deg C)
Eg
g S
urv
ival
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
SHIRAZ Outputs
• Number of population alive by lifestage & area
• Life-cycle productivity
1990 2000 2010 2020 20300
500
1,000
1,500
2,000
Ob-served
Year
Nu
mb
er
of
Sp
rin
g
Ch
inook S
paw
ners
Next Steps
• Complete PHABSIM data collection and analysis
• Continue to build SHIRAZ models• Reporting• Data Transfer Workshop
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
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