One Model to Rule them All: The Illinois Groundwater Model

George S. Roadcap, Daniel B. Abrams, Daniel R. Hadley, Devin H. Mannix

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Modelers at the Illinois State Water Survey have created many different models for different aquifers and purposes over the last 50 years. As our understanding of the interconnections between the different aquifers has advanced through time, many of these models have unfortunately gone out of date. To better address the growing number of water supply issues that impact multiple aquifers and regions, the existing models needed to be combined into one overarching MODFLOW model with a common grid system and input database. The new model is essentially merging the details from several finer-scale grids of the glacial aquifers and a coarser-scale grid of the deep sandstone aquifers that covers the northern half of the state and extends into Wisconsin, Iowa, and Indiana. The database for the model keeps all the details, such as geologic surfaces, at a fine resolution so that new analyses of can be run with telescopic mesh refinement (TMR) or unstructured grids. Calibration checks were necessary after adjusting the grids and layers of the finer models, such as those for the Mahomet Aquifer and St Charles Aquifer, to match those of the larger model. Tools have been developed to efficiently update both regional and local scale models when necessary, as well as to check any changes in calibration that may have taken place. An additional advantage of the one model approach is eliminating the problem of changing personnel or models not functioning in the future because of a software or computer upgrades.
Original languageEnglish (US)
Title of host publicationProceedings of the MODFLOW and More 2017 Conference
StatePublished - 2017


  • ISWS


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