MODFLOW-NWT model used to evaluate groundwater withdrawal scenarios for the Rush Springs aquifer upgradient from the Fort Cobb Reservoir, western Oklahoma, 1979-2015, including streamflow, base flow, and precipitation statistics

A previously published MODFLOW-NWT groundwater-flow model for the Rush Springs aquifer in western Oklahoma (using 1 steady state stress period followed by 444 monthly stress periods representing 1979-2015; Ellis, 2018a) was used as the basis of several groundwater-use scenarios. The model is a 3-layer model including the Cloud Chief formation (confining unit of the Rush Springs aquifer), alluvial and terrace deposits, and the Rush Springs aquifer. The scenarios were used to assess the effects of increasing groundwater withdrawals from the Rush Springs aquifer on base flows to streams that flow into Fort Cobb Reservoir to address concerns over groundwater use reducing inflows to the lake. The effects of groundwater use on base flow were assessed using four scenarios: (1) scaling the equal-proportionate-share rate estimated by Ellis (2018a), (2) scaling historical groundwater withdrawals, (3) scaling historical groundwater withdrawals using zones, and (4) base flow depletion simulations. This USGS data release contains all input and output files for the groundwater-flow simulations and streamflow and base-flow statistics described in the associated model documentation report (https://doi.org/10.3133/sir20245002). Supporting geospatial data are provided that were used to help construct the scenarios and used to display model outputs.