MODFLOW-NWT model used to simulate groundwater levels in the Des Moines River alluvial aquifer near Des Moines, Iowa

The U.S. Geological Survey constructed a steady-state numerical groundwater flow model in cooperation with Des Moines Water Works (DMWW) to simulate groundwater flow conditions in the Des Moines River alluvial aquifer (DMRA) during winter low-flow conditions typical of December 2018-2020. The Des Moines River alluvial aquifer (DMRA) is an important source of water for Des Moines Water Works (DMWW), the municipal water utility that serves residential and commercial water needs in the city of Des Moines, Iowa and surrounding municipalities. A comprehensive understanding of groundwater flow processes in the DMRA is needed for DMWW to make decisions related to the management of this water resource. A three-layered model was constructed using MODFLOW-NWT to simulate an area of about 15 square kilometers near Prospect Park in Des Moines, Iowa. The model has 130 rows and 130 columns of cells within the model boundary. Parameter ESTimation software (PEST) was used for model calibration to assess and optimize performance of individual parameters including the horizontal and vertical hydraulic conductivity of the various units, evapotranspiration rate, and recharge rate. This USGS data release contains all the input and output files for the simulations described in the associated model documentation report (https://doi.org/10.3133/ofr20211110).