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 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 Downloaded from the “seamless.usgs”, EROS Data Center Grid cell size = 30m Grid cell size = 30m National Hydrography Dataset (NHD) Stream network, downloaded from the USGS 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. 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) Hydrologic soil groups (A,B,C and D) Land Use/Land Cover (LULC) data, EPA 9 categories of major land use types. 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 1.DEM Reconditioning 2.Fill Sinks 3.Flow Direction 4.Flow Accumulation 5.Stream Definition 6.Stream Segmentation 7.Catchment Grid 8.Catchment Polygon 9.Drainage Line 10.Adjoint Catchment 11.Drainage Point

Watershed Delineation

Infiltration rate estimation Infiltration rate ( Precipitation – Runoff – Evaporation ) = 47 in/yr * 47 in/yr * 50 = 3.8 in/yr Runoff at the Site No.7 at SRS Fac : 36,087 cells => 3.5 * 10 8 ft 2 Precipitation at CLARK HILL 1 W, SC Pan Evaporation rate - 50 in/yr

Data Preparation for Infiltration rate Grids SCS curve equation for direct runoff Intersect (GeoProcessing Wizard) + Land Use Statsgo

Infiltration Grid

Infiltration Rate Grids

MODFLOW 2000 Three-dimensional finite-difference groundwater model ‘RCH’package in MFI2K.EXE Groundwater pathlines from ORWBG to FMB to FMB Produced by Dr.Charbeneau

Future work Pollutants loading due to Non-point Source Pollution Pollutants loading due to Non-point Source Pollution Analysis of the Monitoring well data Analysis of the Monitoring well data Thanks to Gill Strassberg, CRWR Gill Strassberg, CRWR Venkatesh M Merwade, CRWR Venkatesh M Merwade, CRWR Lynn Shirley, Ph.D, The University of South Carolina Lynn Shirley, Ph.D, The University of South Carolina Dr.Maidment Dr.Maidment