TAILWATER PREDICTIONS FOR THE LAKE BRAZOS DAM GIS IN WATER RESOURCES FALL 2004 BY JACOB YOUNG HYDRAULIC ENGINEERING, USU

PROJECT SCOPE

PROJECT SCOPE

PROJECT SCOPE

OBJECTIVES PROVIDE INSTREAM FLOWS FOR THE BRAZOS RIVER AT THE TAILWATER OF THE DAM USE THE SCS CURVE NUMBER APPROACH IN GIS TO DO SO

SCS CN METHOD

FIRST STEP AQUIRE THE DATA ESTABLISH A PROJECTION NHD DATA DEM’S LAND COVER SOILS PRECIPITATION ESTABLISH A PROJECTION

GIS ANALYSIS ISOLATE THE TEHUACANA CATCHMENT USING ArcHYDRO

GIS ANALYSIS CREATE CODING SYSTEM

GIS ANALYSIS CREATE CODING SYSTEM

GIS ANALYSIS ISOLATE LAND COVER RASTER DATA ISOLATE SOILS POLYGON SHAPEFILE APPLY CODE SYSTEM CONVERT SHAPEFILE TO RASTER USING CODE FIELD SUM CODE FIELDS USING RASTER CALCULATOR

GIS ANALYSIS NOW HAVE ENCODED CURVE NUMBER RASTER JOIN THE LOOK UP TABLE CONVERT RASTER TO POLYGON

GIS ANALYSIS ADD (S) FIELD TO POLYGONS CALC. VALUE WITH EQ. CONVERT POLYGON TO RASTER USING (S) FIELD AS THE VALUE

GIS ANALYSIS APPLY PRECIPITATION DATA RASTER DATA FOR THE 100 YR. STORM ISOLATE CATCHMENT PORTION USE RASTER CALC. WITH (S) VALUE AND PRECIP. RASTERS AQUIRE WEIGHTED FLOW ACCUMULATION USING ArcHYDRO

USING OUTPUTS TO CALC. INSTREAM FLOWS WEIGHTED ACCUMULATION IS EQUIVALENT TO AQ TERM D – STORM DURATION Tc – TIME OF CONCENTRATION

QUESTIONS? THANKS TO: FREESE AND NICHOLS ENG. DR. TARBOTON DR. MAIDMENT COLLIN ROBINSON