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Application of GIS and Terrain Analysis to Watershed Model Calibration for the CHIA Project. Sam Lamont Robert Eli Jerald Fletcher. Background. CHIA: Cumulative Hydrologic Impact Assessment of a mine site Required of WVDEP , for each proposed mine permit
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Application of GIS and Terrain Analysis to Watershed Model Calibrationfor the CHIA Project Sam Lamont Robert Eli Jerald Fletcher
Background • CHIA: Cumulative Hydrologic Impact Assessment of a mine site • Required of WVDEP , for each proposed mine permit • Surface and groundwater quality and quantity
WVU’s Role • Ultimate goal: Graphical tool to simulate pre- and post-mining conditions • Water quantity: Calibrate watershed model (HSPF) to 235 basins in WV
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
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
Modeled Precipitation Grid - Hourly Precip - 1948 – 2002 - 5 km resolution
How HSPF Represents a Watershed Outlet point • 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 Watershed boundary Stream reach Flow Direction
Model Calibration • Trial and error: 1. Run Model 2. Compare output 3. Adjust parameters 4. Repeat • Other software assists this process
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…
Topographic Index • Beven and Kirkby, 1979 TI = ln(a/tanB) a = area B = slope (relative wetness) Example: Abes Run, Canaan Valley
Drainable Volume - Volume of watershed above a particular elevation
Future steps: - Fine-tune calibration: Continue searching for patterns - Validate model - Mine site modeling - Link with WCMS Conclusion