Watershed delineation and data preparation for groundwater modeling using GIS in the Savannah River Site GIS term project presentation November 25, 2003.

Watershed delineation and data preparation for Watershed delineation and data preparation for groundwater modeling using GIS groundwater modeling using GIS

in the Savannah River Sitein the Savannah River Site

GIS term project presentationGIS term project presentation

November 25, 2003November 25, 2003

Prepared by Jaehak JeongPrepared by Jaehak Jeong

OutlineOutline

Introduction

Objective

Data description

Watershed Delineation

Infiltration rate

Conclusion

Future work

ObjectiveObjective

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 descriptionSite 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 DataGIS Data

Digital Elevation Model (DEM)Digital Elevation Model (DEM) Downloaded from the “seamless.usgs”, EROS Data CenterDownloaded from the “seamless.usgs”, EROS Data Center Grid cell size = 30mGrid cell size = 30m

National Hydrography Dataset (NHD) National Hydrography Dataset (NHD) Stream network, downloaded from the USGSStream network, downloaded from the USGS

Statsgo - State Soil Database (1:250,000 scale), USDAStatsgo - State Soil Database (1:250,000 scale), USDA Contains soil properties and soil interpretations for engineering, water Contains soil properties and soil interpretations for engineering, water

management, etc and wildlife uses of the soil. 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, EPALand Use/Land Cover (LULC) data, EPA 9 categories of major land use types.9 categories of major land use types.

Data PreparationData Preparation

DEM quadrangles were merged into one. ( from ’52’ to ‘1’ )DEM quadrangles were merged into one. ( from ’52’ to ‘1’ )

Merged DEM was masked onto the 1Km buffered boundary Merged DEM was masked onto the 1Km buffered boundary coverage.coverage.

NHD, Statsgo, LandUse data were clipped on the 1Km buffered NHD, Statsgo, LandUse data were clipped on the 1Km buffered boundary coverage.boundary coverage.

Projection : UTM Zone 17Projection : UTM Zone 17

Datum : North American Datum 1983 Datum : North American Datum 1983

Units : metersUnits : meters

Terrain PreprocessingTerrain 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 DelineationWatershed Delineation

Infiltration rate estimationInfiltration rate estimation

y = 0.1743x + 9.6831

R2 = 0.2257

0

10

20

30

40

50

60

0 20 40 60 80

Monthly Precipitation (cfs)

Mo

nth

ly R

un

off

(cfs

)

• Infiltration rate ( Precipitation – Runoff – Evaporation ) = 47 in/yr - 0.174 * 47 in/yr - 0.7 * 50 = 3.8 in/yr

• 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

cfs56.22592000sec

month)

0.3048mft

(30ms36,087cell12inft

month5in

ionPrecipitatVolumetric 2

Data Preparation for Infiltration rate GridsData Preparation for Infiltration rate Grids

SCS curve equation for direct SCS curve equation for direct runoffrunoff

Intersect (GeoProcessing Wizard)Intersect (GeoProcessing Wizard)

+

)0.8S(P)0.2S(P

Q,10CN1000

S2

Land Use Statsgo

Infiltration Grid Infiltration Grid

ORWBG

Four Mile Branch

Infiltration Rate Grids Infiltration Rate Grids

infiltgrid

[in/yr]

12.5

14.8

16.2

ORWBG

Four Mile Branch

MODFLOW 2000MODFLOW 2000

Three-dimensional finite-difference groundwater model Three-dimensional finite-difference groundwater model

‘‘RCH’RCH’ package in MFI2K.EXEpackage in MFI2K.EXE

Groundwater pathlines from ORWBGGroundwater pathlines from ORWBG

to FMBto FMB

Produced by Dr.Charbeneau

Future workFuture work Pollutants loading due to Non-point Source Pollution Pollutants loading due to Non-point Source Pollution Analysis of the Monitoring well dataAnalysis of the Monitoring well data

Thanks toThanks to Gill Strassberg, CRWRGill Strassberg, CRWR Venkatesh M Merwade, CRWRVenkatesh M Merwade, CRWR Lynn Shirley, Ph.D, The University of South CarolinaLynn Shirley, Ph.D, The University of South Carolina Dr.MaidmentDr.Maidment