DIGITAL ELEVATION MODELING GEOG 421: DR. SHUNFU HU, SIUE Project One Steve Klaas Fall 2013

Introduction Project One Study Area: Calhoun County Elevation Data: Two 30m NED DEM files (.tif) Steps: Data Preprocessing Terrain Preprocessing Terrain Processing Stream Network Analysis Watershed Boundaries Hydrological Modeling Comparison with Real Data Digital Elevation Model Calhoun County, Illinois

USDA NRCS:  NED 30m DEM (2 Images in TIF format)  US Census County Outline  NHD Rivers, Water Bodies, Streams  USDA SSURGO Soil Data  NLCD Land Use/Land Cover NOAA Meteorological Data:  Hourly Precipitation Totals USGS River Gage Data:  River and Stream Gage Data

Methodology Spatial Analyst Tools Project Raster: Illinois State Plane West-Feet Convert Z units to Feet using Raster Calculator Convert to Integer Data Type Build Raster Attribute Table DEM Data Preprocessing

Methodology Data Management Tools Mosaic to New Raster GRID format DEM Mosaic and Format Transformation

Methodology Spatial Analyst Tools Mosaic to New Raster Tool Output: GRID format DEM subset to shape of county Reduces DEM size Improves Processing Time Subset Image to County Line using Extract by Mask Tool

Methodology Spatial Analyst Tools Hillshade Tool Contour Tool

Methodology Spatial Analyst Tools Aspect Tool Slope Tool

Extension for ArcGIS Available for free from Army Corps of Engineers Simplifies Data Processing tasks for Hydrology

Left: Drainage Lines Right: Drainage Points

Darker color indicates greater flow

Color indicates the direction of overland flow

Model allows user to choose points, providing watershed definition for each point.

The project successfully modeled the hydrology of Calhoun County, Illinois. Skills Acquired: Acquisition, Data Preparation, and Processing of National Elevation Dataset DEMs. Hydrology work flow using the ArcHydro Tools extension. Deliverables Provided: Slope Map Aspect Map Hillshade Map Stream Definition Drainage Line Definition Drainage Point Definition Flow Direction Definition Flow Accumulation Definition Watershed and Catchment Delineation