Use of GIS to Integrate Spatial Data in Instream Flow Assessments

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Use of GIS to Integrate Spatial Data in Instream
Flow Assessments

• Dr. Thomas B. Hardy
• Associate Director
• Utah Water Research Laboratory
• Utah State University

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What is Instream Flows?

• Determine the Inter- AND Intra-annual flow
  regimes that support the critical
• Physical Processes
• Chemical Processes
• Biological Processes
• Within river systems necessary to maintain,
  enhance and/or restore aquatic resources

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What is typically undertaken?

• Physical characterization of the river channel
  topography
• Development of calibrated hydrodynamic models
• Integration of spatially relevant data
• Substrates
• Vegetation
• Development of calibrated and validated
  biological model(s)

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Klamath River Example
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Study Site Delineations within River Reaches

• Study sites were selected to represent
  availability of aquatic habitat types within a
  particular River Reach
• Study site boundaries were selected such that all
  major habitat types present in a reach were
  represented
• Site locations and boundaries were field reviewed
  by a Technical Team

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Physical Characterization of River Channels

• Data Acquisition of Channel Characteristics
• Three Dimensional Channel Topographies
• GIS based Integration of Physical Attributes
• Provides the Spatial Template for Hydrodynamic
  Modeling
• Provides the Spatial Template for Biological
  Modeling

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Low Elevation High Resolution Aerial Photography
Softcopy Photogrammetry
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Underwater Topographies Acoustic Mapping
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Data Collection
GPS
Real time correction
Power Supply
Computers
Sonar
ADP
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Integrated Topographies are Represented as a
Computational Mesh for Hydraulic and Habitat
Modeling
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GIS Integration to Derive Mesh Node Properties

• GIS is used to assign n-dimensional node
  attributes for use in habitat modeling
• For example a typical physical attribute input
  file for habitat modeling will include for each
  node point
• Substrate
• Vegetation
• Depth
• Velocity

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Hydrodynamic Modeling

• Two-dimensional hydraulic modeling used to
  estimate depth and mean column velocities at all
  node locations
• Capable of representing topography dependent
  changes in micro-scale flow patterns
• Ideally suited for integrating node specific
  hydraulics with spatially derived physical,
  chemical, and/or biological attributes in habitat
  modeling

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Development and Validation of Biological Criteria
and Habitat Modeling

• Spatially Explicit Fish Observation Data
  collected for Habitat Suitability Curve
  Development and Habitat Model Validation
• Habitat Modeling included Integrating Behavioral
  Based Rules
• Escape Cover Modeling for Fry Life Stages

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Spawning Depth, Velocity, and Substrate
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Fry Escape Cover Empirical Data
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Fry Escape Cover ModelingBehavioral Rule

• Evaluate the depth and velocity at the current
  node for potential suitability as long as the
  following conditions are met
• The current node must be within a threshold
  distance of a node containing suitable cover AND
• The node containing the cover must have a depth
  of water at least equal to or greater than a
  threshold depth to allow the fry to enter the
  cover
• The node containing cover must have velocities lt
  maximum velocity at which fry can swim

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Instream Flow Recommendations

• Utilized a Life Stage and Species Priority
  Ranking System based on
• Life History Cycle - Periodicity
• Endangered Species
• Spawning/Incubation
• Fry
• Juvenile
• Adult

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Instream Flow Recommendations

• Benchmarked Against No-Project Habitat
  Availability
• Flow Reductions Permitted as long as
• Maintained Habitat within 90 percent of
  No-Project Habitat Availability within a given
  Exceedance Water Year Type
• Flow Reductions could not result in significant
  loss to combined species and life stages in any
  given month

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Water Temperature Simulations

• As flow releases below Iron Gate Dam drop below
  1000 cfs
• Maximum daily temperatures can exceed upper
  thermal limits for salmon
• Increases the range between maximum and minimum
  daily temperatures
• Associated with increased rates of parasitism and
  thermal shock

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Water Year Exceedance LevelInstream Flow
Recommendations
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Summary

• Each step and element of the study was reviewed
  by the Technical Team
• Field observations of different species and life
  stages at different flows validated physical
  habitat modeling results
• Flow recommendations preserve the underlying
  characteristics of the estimated no-project
  hydrology and associated physical habitat
• Flow recommendations allow for between year and
  within year flow variability
• Flows below 1000 cfs increase the ecological
  risk to the fisheries due to increased diurnal
  temperature fluctuations and maximum daily
  temperatures

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Researchers have already cast much doubt on the
subject and if they continue their studies we
shall soon know nothing at all. Mark Twain