Application of GIS and Terrain Analysis to Watershed Model Calibration for the CHIA Project

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Application of GIS and Terrain Analysis to
Watershed Model Calibrationfor the CHIA Project
Sam Lamont Robert Eli Jerald Fletcher
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Background

• CHIA Cumulative Hydrologic
  Impact Assessment of a mine site
• Required of WVDEP , for each proposed mine
  permit
• Surface and groundwater quality and quantity

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WVUs Role

• Ultimate goal Graphical tool to simulate pre-
  and post-mining conditions
• Water quantity Calibrate watershed model (HSPF)
  to 235 basins in WV

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235 Study Watersheds and Their Outlets
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BASINS-GIS Framework

• ArcView based environment for display and
  analysis of watershed features
• Develops input files for HSPF
• - watershed file (landuse, slope, area)
• - stream network
• - reach attributes
• - point sources
• This project WCMS

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HSPF Hydrologic Systems Program - Fortran

• Continuous
• Calculates water balance for each time step
• R P ET IG S
• where R Runoff
• P Precipitation
• ET Evapotranspiration
• IG Deep/Inactive Groundwater
• S Change in soil storage
• Surface and sub-surface hydrology
• Inputs Precip, PET, Temp
• Output Simulated flow

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Modeled Precipitation Grid
- Hourly Precip - 1948 2002 - 5 km resolution
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How HSPF Represents a Watershed

• Example
• - 5 Sub-watersheds
• 5 Stream reaches
• (Storage-Outflow routing)
• - Land use types
• Forest (Steep,Moderate, Mild)
• Shrub-land
• Pasture/Grassland
• Urban
• Mine
• Barren
• Row Crop
• Wetland
• Surface Water

Outlet point
Watershed boundary
Stream reach
Flow Direction
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Percent Slope Distribution
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5 Calibration Watersheds
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Model Calibration

• Trial and error
• 1. Run Model
• 2. Compare output
• 3. Adjust parameters
• 4. Repeat
• Other software assists this process

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HSPEXP Calculates error statistics, provides
advice, plots
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Typical Results Tygart Valley River at Elkins
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Further Proposed Terrain Analysis for Calibration
Improvement

• Hoes does watershed shape and structure relate
  to hydrology?
• Searching for an index defining hydrologic
  characteristics.

Some examples
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Topographic Index

• Beven and Kirkby, 1979
• TI ln(a/tanB)
• a area
• B slope
• (relative wetness)

Example Abes Run, Canaan Valley
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Rugosity-Surface Area/Planar Area
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Drainable Volume
- Volume of watershed above a particular elevation
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Future steps - Fine-tune calibration
Continue searching for patterns - Validate
model - Mine site modeling - Link with WCMS
Conclusion
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Questions?