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Watershed delineation and data preparation for groundwater modeling using GIS in the Savannah River Site. GIS term project presentation November 25, 2003 Prepared by Jaehak Jeong. Outline. Introduction Objective Data description Watershed Delineation Infiltration rate Conclusion
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Watershed delineation and data preparation for groundwater modeling using GIS in the Savannah River Site GIS term project presentation November 25, 2003 Prepared by Jaehak Jeong
Outline • Introduction • Objective • Data description • Watershed Delineation • Infiltration rate • Conclusion • Future work
Objective • To model the surface water hydrology by delineating the watershed • To construct the infiltration grid which represents the topology and the geography for groundwater modeling • To get friendly with the ArcGIS
Site description • Located at the border of SC and GA • Occupies 310 square miles. (about the size of the Washington, D.C. beltway) • Constructed during the early 1950s to produce the basic materials for nuclear weapons (primarily tritium and plutonium-239) • Included on the National Priorities List (NPL) in 1989. • Old Radioactive Waste Burial Ground (ORWGB) is identified as a RCRA/CERCLA unit
GIS Data • Digital Elevation Model (DEM) • Downloaded from the “seamless.usgs”, EROS Data Center • Grid cell size = 30m • National Hydrography Dataset (NHD) • Stream network, downloaded from the USGS • Statsgo - State Soil Database (1:250,000 scale), USDA • Contains soil properties and soil interpretations for engineering, water management, etc and wildlife uses of the soil. • Hydrologic soil groups (A,B,C and D) • Land Use/Land Cover (LULC) data, EPA • 9 categories of major land use types.
Data Preparation • DEM quadrangles were merged into one. ( from ’52’ to ‘1’ ) • Merged DEM was masked onto the 1Km buffered boundary coverage. • NHD, Statsgo, LandUse data were clipped on the 1Km buffered boundary coverage. • Projection : UTM Zone 17 • Datum : North American Datum 1983 • Units : meters
Terrain Preprocessing • DEM Reconditioning • Fill Sinks • Flow Direction • Flow Accumulation • Stream Definition • Stream Segmentation • Catchment Grid • Catchment Polygon • Drainage Line • Adjoint Catchment • Drainage Point
Infiltration rate estimation • Runoff at the Site No.7 at SRS • Fac : 36,087 cells => 3.5 * 108 ft2 • Precipitation at CLARK HILL 1 W, SC • Pan Evaporation rate • - 50 in/yr • Infiltration rate ( Precipitation – Runoff – Evaporation ) • = 47 in/yr - 0.174 * 47 in/yr - 0.7 * 50 • = 3.8 in/yr
Data Preparation for Infiltration rate Grids • SCS curve equation for direct runoff • Intersect (GeoProcessing Wizard) + Land Use Statsgo
MODFLOW 2000 • Three-dimensional finite-difference groundwater model • ‘RCH’ package in MFI2K.EXE • Groundwater pathlines from ORWBG to FMB Produced by Dr.Charbeneau
Future work • Pollutants loading due to Non-point Source Pollution • Analysis of the Monitoring well data • Thanks to • Gill Strassberg, CRWR • Venkatesh M Merwade, CRWR • Lynn Shirley, Ph.D, The University of South Carolina • Dr.Maidment