MODFLOW model used in simulation of groundwater flow and analysis of projected water use for the Rush Springs aquifer, western Oklahoma

In 2018 The U.S. Geological Survey, in cooperation with the U.S. Bureau of Reclamation and the Oklahoma Water Resources Board, published a calibrated numerical groundwater- flow model and associated model documentation report that evaluated the effects of potential groundwater withdrawals on groundwater flow and availability in the Rush Springs aquifer in western Oklahoma. The results of groundwater-availability scenarios run on the calibrated numerical groundwater-flow model could be used by the Oklahoma Water Resources Board to evaluate the maximum annual yield of groundwater from the Rush Springs aquifer in Oklahoma. A conceptual groundwater-flow model is a simplified description of the major inflow and outflow sources (hydrologic boundaries) of a groundwater-flow system as well as an accounting of the estimated mean flows from those sources (water budget) for a specified period of time. The conceptual model was necessary to provide constraints used in the construction and calibration of a scientifically defensible numerical groundwater-flow model that reasonably represents the groundwater-flow system. A finite-difference numerical groundwater-flow model of the Rush Springs aquifer was constructed by using MODFLOW-2005 with the Newton formulation solver (MODFLOW-NWT). Data inputs for each package were specified in machine-readable text files. The numerical model of the Rush Springs aquifer had 1,362 rows, 1,083 columns, about 554,000 active cells of 500 by 500 ft, and 3 convertible layers. The top layer (layer 1) represented the Permian-age Cloud Chief Formation. The Rush Springs aquifer is composed of Permian-age Whitehorse Group. The second layer (layer 2) represented the undifferentiated Quaternary-age alluvium and terrace deposits, as well as the upper 30 ft of the Whitehorse Group. The bottom layer (layer 3) represented the remainder of the Rush Springs Formation. The model active area was modified from Neel and others (2018). The numerical model was temporally discretized into 444 monthly transient stress periods representing the period 1979-2015. An initial steady-state stress period, in which the groundwater-flow equation had no storage component, represented mean annual inflows to and outflows from the aquifer and produced a solution that was used as the initial condition for subsequent transient stress periods. The numerical model was constructed in units of meters and days. This USGS data release contains all of the input and output files for the simulations described in the associated model documentation report (https://doi.org/10.3133/sir20185136)

[
  "010:12"
]

[
  "geospatial"
]