Integrating GIS and Hydrology for Flood Risk Analysis

Spatial analysis using GIS was evaluated for its ability to predict the potential hazard of a flood event in the Illinois River region in the State of Illinois. The data employed in the analysis are available to the public from trusted organizations such as Illinois State Geological Survey (ISGS), and the US Geological Survey (USGS). The purposes of this study are to 1) examine the applicability of GIS spatial analysis to determine flood inundation risk, and 2) to determine how to do so with the least amount of data possible, while still producing an accurate flood inundation risk map. This study concentrates on areas that have stream gauge data with definable flood stage(s) and utilizes the Inverse Distance Weighted (IDW) spatial analysis interpolation method on different digital elevation models (DEM) with different resolutions to determine the potential flood level over the study area. Resulting maps created for the Illinois River region yielded about 80% agreement to the actual effects of the Illinois River flood near Peoria on April 23rd, 2013. As a result, it was concluded that it is possible to create a decent flood prediction map using only two initial input data layers: stream gauges, and a digital elevation model (DEM)