Elevation, Flow Accumulation, Flow Direction, and Stream Definition Data in Support of the Illinois StreamStats Upgrade to the Basin Delineation Database

The U.S. Geological Survey (USGS), in cooperation with the Illinois Center for Transportation and the Illinois Department of Transportation, prepared hydro-conditioned geographic information systems (GIS) layers for use in the Illinois StreamStats application. These data were used to delineate drainage basins and compute basin characteristics for updated peak flow and flow duration regression equations for Illinois. This dataset consists of raster grid files for elevation (dem), flow accumulation (fac), flow direction (fdr), and stream definition (str900) for each 8-digit Hydrologic Unit Code (HUC) area in Illinois merged into a single dataset. There are 51 full or partial HUC 8s represented by this data set: 04040002, 05120108, 05120109, 05120111, 05120112, 05120113, 05120114, 05120115, 05140202, 05140203, 05140204, 05140206, 07060005, 07080101, 07080104, 07090001, 07090002, 07090003, 07090004, 07090005, 07090006, 07090007, 07110001, 07110004, 07110009, 07120001, 07120002, 07120004 (0712003 was combined into this HUC), 07120005, 07120006, 07120007, 07130001, 07130002, 07130003, 07130004, 07130005, 07130006, 07130007, 07130008, 07130009, 07130010, 07130011, 07130012, 07140101, 07140105, 07140106, 07140108, 07140201, 07140202, 07140203, and 07140204.