MODFLOW-NWT model of the glacial aquifer system north of Aberdeen, South Dakota, through water year 2015

A previously developed three-dimensional groundwater flow model
(https://doi.org/10.3133/sir20125183) of the three primary aquifers
in the region north of Aberdeen, South Dakota, was revised to
assist the City of Aberdeen with water-resource planning. The
principal aquifers are the Elm, Middle James, and Deep James.
The numerical model is intended to be used to (1) simulate
hydrologic scenarios of interest to groundwater managers and to
advance the understanding of groundwater budgets and components
including recharge, discharge, and aquifer storage, (2) compute
historical and projected system response to natural and anthropogenic
stresses, and (3) evaluate potential withdrawal scenarios to assist
with water-management decisions.
The three-dimensional groundwater-flow model was developed using
the USGS's numerical modeling software, MODFLOW-NWT. The
model included both steady-state (mean) and transient (temporally
varying) conditions. Steady-state data were from October 1, 1974 to
September 30, 2009, and the transient time period included data from
October 1, 1974 to September 30, 2015. The model was calibrated by
attempting to match simulated and measured or estimated hydraulic
heads, differences in hydraulic heads between aquifers, and stream
base flow. Water budgets for the model's layers area were produced
with ZONEBUDGET.
This USGS data release contains all of the input and output files for
the model described in the associated model documentation report
(http://doi.org/10.3133/sir20185137). The data release also includes
(1) MODFLOW-NWT (version 1.1.4) source code, and (2) ZONEBUDGET
(3.01) source code.