MODFLOW-2000 model used to illustrate the differences in flow paths and travel times when three-dimensional kriging is used to estimate the hydraulic conductivity distribution as compared to manual determinations of hydraulic conductivity distribution

A three-dimensional (3D) groundwater flow model of the glaciated sediments around Elkhart, Indiana was constructed as part of the U.S. Geological Survey Groundwater Resources Program using lithologic records from water well logs. Texture-based hydraulic conductivities were assigned to vertical intervals along each lithology record. A three-dimensional kriging program read texture-based hydraulic conductivity values for each vertical interval and calculated a continuous 3D distribution of hydraulic conductivity for the entire model domain. The model was calibrated to hydrologic conditions in May and June of 1979. The model was used to simulate groundwater flow paths from points of recharge to points of discharge. These flow paths were compared to flow paths generated by an existing model (https://pubs.usgs.gov/wri/1997/4204/report.pdf) that was constructed using a manual approach to create the hydraulic conductivity distribution and calibrated to the same hydrologic conditions. The model using the kriged hydraulic conductivity distribution had 30 vertically discretized layers, and the model using the the manually created hydraulic conductivity distribution had two vertically discretized layers. This USGS data release contains the model input and output files for the simulations described in the associated documentation report (https://doi.org/10.3133/sir2019-5088)