US national wide gSSURGO based floodplain maps are developed by using Gridded Soil Survey Geographic (gSSURGO) database. Specifically, the SSURGO map units are joined to certain key attributes in the muaggatt and component tables. After joining the spatial data to ‘muaggatt’ and ‘component’ tables, map unit polygons are selected by the following two queries: (1) "geomdesc" LIKE '%flood%' AND "comppct_r" >= 85) OR "taxsubgrp" LIKE '%fluv%'; (2) “muname" ='Water' OR "flodfreqdcd" in ('Rare', 'Occasional', 'Frequent', 'Very Frequent')". The result from this query, which is a polygon feature class or shapefile, is then dissolved to remove any area less than 15000 square meters are removed. More details about this approach can be found in the following publication: Sangwan, Nikhil, and V. Merwade, A faster and economical approach to floodplain mapping by using soil information, Journal of American Water Resources Association, 51(5): 1286-1304. (2015)

Researchers should cite this work as follows:

• Merwade, V. M.; Du, L.; Nikhil Sangwan (2016). gSSURGO-based Floodplain Maps of Illinois. Purdue University Research Repository. doi:10.4231/R7TD9V8K

  BibTex | EndNote

1. biota
2. Civil Engineering (Dept)
3. Environment
4. floodplain maps
5. Forestry and Natural Resources
6. Geographic Information Systems (GIS)
7. geoscientific
8. gSSURGO soil Data
9. Hydrology
10. Illinois
11. inland water
12. shapefile

The publication is part of the series below:

• gSSURGO-based Floodplain Maps of the United States

  This series provides shapefiles showing the natural floodplain for the United States. These floodplain polygons are extracted from the gSSURGO soil data from the Natural Resources Conservation Service (NRCS).

This floodplain map was created with Esri ArcGIS 10.3.1, and revised in March 2016. It is in GCS North American 1983 coordinate system.