Instream Flow Needs and Reservoir Elevation Study

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Instream Flow Needs and Reservoir Elevation
Study

• Claytor Lake Project
• FERC Project No. 739

Louis Berger Group Thomas R. Payne
Associates January 24, 2007 - Pulaski, Virginia
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LBG/TRPA Experience with IFN

• Conducting IFN studies since 1981
• Worked on 500 instream flow studies
• LBG and TRPA team frequently
• Nearing completion of Smith Mtn. IFN
• Currently conducting IFN studies
• New Melones Dam, Stanislaus River, CA
• Boundary Dam, Pend Oreille River, WA
• McCloud Pit Project, McCloud River, CA

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Claytor Lake IFN Study Objectives

• Create incremental habitat indicies
• Review species life histories
• Compare regulated and unregulated flow
• Evaluate project effects on habitat
• Relate releases to reservoir elevations
• maintenance drawdown
• withdrawals and consumptive uses
• Assess means for getting public flow info

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Claytor Lake IFN Study Components

• Physical Habitat Simulation of New River
• Calculate habitat indicies with PHABSIM
• Elevation study of Claytor Lake
• Impacts to recreational uses
• Dynamic flow routing model
• Travel time and flow attenuation
• New River water temperature modeling
• Thermal effects of alternatives

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Study Area Map
Highway 460 Bridge Glen Lyn
Pembroke
County Line - Big Falls
57 river miles
Radford
Claytor Lake Dam
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PHABSIM Elements

• Habitat mapping
• Transect selection
• Hydraulic data collection
• Computer calibration
• Habitat suitability criteria
• Physical Habitat Index - WUA/PHI (?)
• Regulated/unregulated hydrology
• Interpretation

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WUA/PHI (?) Habitat Index
?
Flow in cubic feet per second
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Habitat Mapping

• Study reach is Dam to Highway 460 Bridge
• Mesohabitat strata typing on river
• run (medium and deep)
• glide
• pool (medium and deep)
• fast riffle (boulder/bedrock)
• slow riffle (gravel/cobble)
• island
• Measured by strata by distance
• Data base for transect selection

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Transect Selection

• Select from predominant and ecologically
  significant strata
• Stratified random selection
• Minimum of 2 transects per strata
• Approximately 18-20 transects in selected
  habitat strata
• Additional transects as necessary
• Selection in field with stakeholders

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Hydraulic Data Collection

• Standard 1-D data collection
• Three S-Q and one velocity data sets
• River2D data collected at islands
• Main channel velocities with ADCP
• Edges and shallows with Price AA
• Target flows (1000, 2500, 5000) cfs
• Extrapolation range (400-12,500) cfs

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ADCP
Teledyne Rio Grande Acoustic Doppler Current
Profiler
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Tethered ADCP in Trimaran
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Plot of ADCP Data
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Computer Calibration

• Standard calibration methods and criteria
• Use River2D for flow splits at islands
• Use 1-Velocity (IFG4) model
• Evaluate extrapolation limits
• Simulate depths and velocities
• Add substrate/cover coding

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Habitat Suitability Criteria (HSC)

• Target species list
• Rock bass White shiner
• Smallmouth bass Northern hog sucker
• Flathead catfish Pocketbook mussels
• Channel catfish Purple wartyback mussels
• Muskellunge Macroinvertebrates (3 species)
• Redbreast sunfish Crayfish
• Bigmouth chub Hellbender
• Greenside darter Riparian vegetation
• Logperch Water willow
• Silver shiner LIFE STAGES?

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Computation of WUA/PHI (?)

• Separate index for each species/life stage
• Standard multiplication of HSC variables
• mean column velocity
• depth
• substrate/cover
• ? habitat index vs. discharge graphs

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Interpretation of WUA/PHI (?)

• Species/life stage prioritization
• Species/life stage periodicity
• Limiting factor evaluation
• Time series modeling (hourly/daily)
• regulated/unregulated comparisons over time
• alternative flow regime comparisons over time
• Dual flow analysis of peaking effects

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Reservoir Elevation Study

• Fall maintenance drawdown impacts
• Withdrawal and consumptive impacts
• Focus on recreational uses of reservoir
• Data sources
• forebay elevations
• flow releases
• inflow data (Allisonia USGS gage)
• reservoir stage-volume curves
• Model Excel-based or HEC-ResSim

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Dynamic Flow Routing

• Compare stream gage data
• Deploy additional gages as needed
• Evaluate flow travel time
• Evaluate flow change attenuation
• Consider accretion and flow magnitude
• Develop routing model (w/ temperature)
• Assess means to communicate results and
  predictions to public

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Water Temperature Modeling

• Needed to assess themal impacts of routing model
  and flow alternatives
• Deploy recording thermographs for year
• Allocate flow accretion among tributaries
• Select temperature model (SNTEMP)
• Calibrate temperature model
• Incorporate with flow routing model
• Focus on recreation and mussel populations

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IFN Study Schedule

• Pre-study meeting - January 2007
• Review of habitat strata and target flows - March
  2007
• Habitat mapping - April 2007
• Hydraulic data collection - May/June 2007
• Modeling and analysis - June-October 2007
• Progress meeting - August 2007
• Preliminary report - November 2007
• Meetings, discussions, comments, recommendations
  - December 2007-April 2008
• Final report to stakeholders - June 2008

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