MODFLOW-NWT model used for the simulation of groundwater flow and analysis of groundwater availability in the Boone and Roubidoux aquifers in northeastern Oklahoma, 1980-2017

The U.S. Geological Survey (USGS), in cooperation with the Oklahoma Water Resources Board (OWRB), constructed a finite-difference numerical groundwater-flow model of the Boone and Roubidoux aquifers in northeastern Oklahoma by using MODFLOW-NWT (version 1.1.4) with the Newton formulation solver to simulate groundwater flow and account for the drying and rewetting of cells within the groundwater-flow model. The numerical groundwater-flow model was discretized into four layers consisting of 354 rows by 261 columns with a 2,000-feet by 2,000-feet cell size. The model layers were used to simulate the Western Interior Plains confining system, the Boone aquifer, the Ozark confining unit, and the Roubidoux aquifer. The model was temporally discretized into one steady-state stress period followed by 456 monthly transient stress periods spanning from January 1980 to December 2017. The steady-state stress period typically consisted of mean annual inputs from January 1980 to December 2017, but inputs from 1979 were included for some of the simulations.