The U.S. Geological Survey in cooperation with the Upper Arkansas Water Conservancy District, created a numerical groundwater-flow model for the Wet Mountain Valley alluvial aquifer using the finite-difference MODFLOW code with the Newton formulation solver. This numerical groundwater-flow model simulates water-budget components, groundwater and surface-water interactions, and evaluates the potential effects of aquifer storage and recovery through an added recharge simulation. The numerical model was spatially discretized into two layers with 261 rows and 133 columns of square cells at 250 meters on each side, for a total of 20,007 active cells. The model was rotated by 36 degrees to the northwest to align with the orientation of the valley and the assumed groundwater-flow directions. The numerical model was temporally discretized into 241 stress periods. The first stress period simulates a mean steady-state period, and the subsequent 240 stress periods were transient and simulate each month from 2000 to 2019. This U.S. Geological Survey data release includes all of the necessary files to simulate the Wet Mountain Valley alluvial aquifer and potential flow paths within it as described in the associated Scientific Investigations Report (https://doi.org/10.3133/sir20245105).