Hydrogeologic inventory of the upper Illinois River Basin – Creating a large data base from well construction records

A large data base consisting of 40,679 well locations and 196,687 lithologic records was created from Illinois, Indiana, and Wisconsin well construction records for wells drilled during the period 1980-1997. The purpose of the database is to provide information for mapping the surface, thickness, transmissivity and hydraulic conductivity of the Quaternary, Silurian/Devonian, and Cambrian/Ordovician age aquifers in the upper Illinois River Basin (UIRB). These digital maps and information will be used for the UIRB study of the National Water-Quality Assessment Program, U.S. Geological Survey (USGS), to facilitate countyor basin-wide three-dimensional (3-D) ground-water flow and transport modeling. A geographic information system (GIS) was used to create and manage the database. Over 50 computer programs were written and utilized to compile and summarize data from various sources.