Turners Falls Instream Flow Study Study Process Overview Study - - PowerPoint PPT Presentation

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turners falls instream flow study study process overview
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Turners Falls Instream Flow Study Study Process Overview Study - - PowerPoint PPT Presentation

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Turners Falls Instream Flow Study Study Process Overview Study Plan Scoping Meeting April 16, 2013 Study Timing Relative to ILP schedule ILP Schedule Proposed Study Plans (PSP): 4/15/13 Study Plan Meeting: 5/14-15/13 Additional

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Turners Falls Instream Flow Study Study Process Overview Study Plan Scoping Meeting April 16, 2013

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ILP Schedule

  • Proposed Study Plans (PSP): 4/15/13
  • Study Plan Meeting: 5/14-15/13
  • Additional Fish and Aquatic Meetings: 5/21-22, 6/4-5/13
  • Seeking to conduct IFIM Study July timeframe
  • Comments due on PSP: 7/14/13
  • Revised Study Plans (RSP): 8/13/13
  • Comments due on RSP: 8/28/13
  • FERC Issues Study Plan Determination Letter 9/12/13 (assuming no disputes)
  • We need stakeholder and FERC approval before initiating study

Why Accelerate?

  • Findings will inform other studies, fish passage alternatives, and potential

impacts on hydropower generation

Study Timing Relative to ILP schedule

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TERMINOLOGY

Macrohabitat – water quality and hydrology Mesohabitat – commonly occurring habitat types Critical habitat – important to a species even if not common Microhabitat – depth, velocity and cover within each mesohabitat Weighted Usable Area - quantitative index of habitat suitability

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PHABSIM Study

1. Study Planning 2. Locate reaches and transects 3. Obtain channel profile and microhabitat data 4. Develop hydraulic model 5. Input suitability rating criteria

  • 6. Output suitability available at

each flow increment of interest

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PHABSIM Study

1. Study Planning 2. Locate reaches and transects 3. Obtain channel profile and microhabitat data 4. Develop hydraulic model 5. Input suitability rating criteria

  • 6. Output suitability available at

each flow increment of interest

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Hypothetical flow control issue

Flow control downstream

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Review physical characteristics

Flow control downstream Repeating channel pattern: riffle/run/pool Unique channel condition:

cobble rapids

Minor tributary

Major tributary

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Link species/lifestages or guilds to specific mesohabitats

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Define overall study area

Flow control downstream Spawning bar Juvenile and adult feeding and holding

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Stratify reaches according to physical, hydrologic and habitat use characteristics

Flow control downstream REACH 1 REACH 2

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Select study sites representative of each reach

Flow control downstream REACH 1 REACH 2 Critical reach study site

Representative reach study site

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Representative Study Site

pool riffle run

Sand bar

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Cell Boundaries are located at breaks in habitat types

pool riffle run

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Cell Boundaries (continued)

pool riffle run

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One transect is located within each longitudinal cell

pool riffle run T-1 T-2 T-3 T-4 T-5

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PHABSIM Study

1. Study Planning 2. Locate reaches and transects 3. Obtain channel profile and microhabitat data 4. Develop hydraulic model 5. Input suitability rating criteria

  • 6. Output suitability available at

each flow increment of interest

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transect T-1 (looking downstream)

Top of bank Toe of bank Edge of water Thalweg

headpin tailpin

Water surface

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Verticals are located along each transect to capture key substrate and profile features

Top of bank Toe of bank Edge of water Thalweg

headpin tailpin

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Verticals and cell boundaries act to divide each segment into a mosaic of known areas

pool riffle T-1 T-2 T-3 T-4 T-5

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COBBLE GRAVEL

SUBSTRATE CLASSIFICATION

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IMBEDDEDNESS

un-imbedded highly imbedded

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VELOCITY REFUGE

Abundant refuges Few refuges

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PHABSIM Study

1. Study Planning 2. Locate reaches and transects 3. Obtain channel profile and microhabitat data 4. Develop hydraulic model 5. Input suitability rating criteria

  • 6. Output suitability available at

each flow increment of interest

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SLIDE 27

Calibration flows are gathered across the flow range of interest

High flow (WSL only) mid flow (WSL and velocities) low flow (WSL and some velocities)

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This permits interpolation and extrapolation of

  • ther flows

100 cfs 1,800 cfs

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PHABSIM Study

1. Study Planning 2. Locate reaches and transects 3. Obtain channel profile and microhabitat data 4. Develop hydraulic model 5. Input suitability rating criteria

  • 6. Output suitability available at

each flow increment of interest

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Habitat Suitability Criteria

  • Depth
  • Velocity
  • Channel Index
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Habitat is “pixilated” into a mosaic

  • f known dimensions
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2D Finite Elements Model

Survey elevations bathymetry

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2D Finite Elements Model

Scenario “A” Scenario “B”

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PHABSIM Study

1. Study Planning 2. Locate reaches and transects 3. Obtain channel profile and microhabitat data 4. Develop hydraulic model 5. Input suitability rating criteria

  • 6. Output suitability available at

each flow increment of interest

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SLIDE 36

Model output: Habitat-flow relationships for each study reach

5000 10000 15000 20000 25000

100 200 300 400 500 600 Habitat Suitability (WUA) Discharge (cfs)

Pleasant River IFIM Study. Habitat and wetted area vs. flow relationship in mid-river (Reach No. 4) riffle run (Sq Ft per 1,000 ft of stream).

YOY Parr

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Suggested Problem-Solving Process

Review hydrology time series Compare habitat under existing and alternate flow scenarios Compare project operation under existing and alternate flow scenarios Assess extent to which all objectives are met under each flow scenario Evaluate trade-offs Re-run alternative scenarios

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Problem-Solving Options

  • Habitat Time Series

– Define applicable bio-periods – develop flow duration data for each – Merge WUA/flow curve with flow duration curve – Look for alternatives that meet habitat and operation objectives

  • Persistent Habitat Analysis

– Map spatial distribution of habitat “hotspots” at paired flows in GIS – Look for pair combinations that provide consistently good habitat – Develop matrix for species/lifestages – Iteratively look for scenarios that balance both operation and habitat

  • bjectives
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Habitat suitability relationship

200 240 280 320 360 400 200 400 600 800 weighted usable area (SQ FT) discharge (CFS)

July - September habitat suitability

RBT adult

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Hydrologic Data

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Hydrograph + habitat

14000 16000 18000 20000 22000 10 20 30 40 50 60 70 80 90 100 Weighted Usable Area ft2/1000ft % of time streamflow was equaled or exceeded

Natural

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Effect of existing flow diversion

14000 16000 18000 20000 22000 10 20 30 40 50 60 70 80 90 100 % of time streamflow was equaled or exceeded Weighted Usable Area ft2/1000ft Natural "worst case" current practice

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14000 16000 18000 20000 22000 10 20 30 40 50 60 70 80 90 100 % of time streamflow was equaled or exceeded Weighted Usable Area ft2/1000ft Natural current practice Alternative "A" Alternative "B" Alternative "C"

Effect of alternative diversion strategies

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Persistent Habitat

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Persistent Habitat