Welcome to the Iowa DNR, Geologic Survey's Watershed Initiative. The purpose of this website is to provide the public with access to sound watershed science.

Watersheds are divided and sub-divided into successively smaller units, each is given a number, called a Hydrologic Unit Code, or HUC.  The eight-digit HUC's,called sub-basins, are shown on the map at the right, in black outline.

If you have questions or comments, please call the Iowa Geological Survey at 319-335-1353, 8:00 A.M. to 4:30 P.M. CST, Monday through Friday. We can also be reached by email at: gis_library@igsb.uiowa.edu.

State-Wide Watershed Information:

Click on any sub-basin to get more information, download data, launch the interactive Watershed Atlas, or continue to explore the watersheds of Iowa.