MODFLOW-NWT model used in simulations of selected climate scenarios of groundwater availability in the North Fork Red River aquifer, southwestern Oklahoma

A previously developed model (https://doi.org/10.3133/sir20175098) was coupled with
downscaled climate model data to determine the impact of climate variability on base
flow and groundwater storage in the North Fork Red River aquifer, Oklahoma. The North
Fork Red River aquifer is an alluvial aquifer that discharges groundwater to the North
Fork Red River, which provides inflow to Lake Altus, an important water source for the
surrounding communities. The impact of climate variability on hydrologic systems and
the resulting effects on basins has become an important topic in assessing future water
resources. Global climate projections from general circulation models, including the
Coupled Model Intercomparison Project Phase 5 (CMIP5), have been developed to
improve the understanding of climate science and forecast future climatic conditions.
Due to the impact of climate variations on groundwater resources, it is important to
communicate the ranges of results with water resource managers. To approximate a
range in future base flow conditions and flow into Lake Altus, the Coupled Model
Intercomparison Project Phase 5 climate data was downscaled to watershed scale
using monthly Bias-Correction Spatial Disaggregation techniques. A time-series of
scaling factors were developed and interpolated for three climate scenarios (central
tendency, warmer/drier, and less warm-wetter) representing a range of future climate
conditions for the period 2045–2074. These scaling factors were then applied to an
existing soil-water-balance model dataset with climate data for the baseline period
1980–2009 to produce recharge and evapotranspiration estimations for this future
period. The downscaled climate data was applied to the finite-difference numerical
groundwater-flow model of the North Fork Red River aquifer using MODFLOW-2005
with the Newton formulation solver (MODFLOW-NWT) which was temporally discretized
into 373 monthly transient stress periods representing the period 1980–2010. Three
climate scenarios (central tendency, warmer/drier, and less warm/wetter) representing
a range of future climate conditions for the period 2045–2074 were simulated. This USGS
data release contains all of the input and output files for the simulations described in the
associated journal article (http://doi.org/10.1007/s10040-020-02230-x).