MODFLOW2005 and GWM-2005 used to optimize managed aquifer recharge in an Updated Version of the Three-Dimensional Numerical Groundwater Flow Model in Northern Utah Valley, Utah County, Utah

An existing three-dimensional groundwater flow model of northern Utah County (https://doi.org/10.3133/sir20095049), was updated for use with the Groundwater Management Process(GWM) for MODFLOW-2005, to evaluate the optimal managed aquifer recharge scenarios with the objective of maintaining acceptable reductions in simulated discharge at 12 groundwater discharge areas along Utah Lake. Groundwater is a primary source of drinking water in northern Utah County.
By 2066, the amount of groundwater withdrawn is estimated to be roughly 65 percent of annual average recharge. To prepare for anticipated future increases in groundwater withdrawals, local cities have identified 16 locations as feasible for managed aquifer recharge. The GWM Process for MODFLOW-2005 was used to investigate optimal managed aquifer recharge scenarios with the objective of maintaining acceptable reductions in simulated discharge at 12 groundwater discharge areas and flowing wells along Utah Lake. The Groundwater-Management Process is applied to a 50-year (2017–66) projection of groundwater conditions using average recharge conditions and a linear increase of approximately 750 acre- feet per year of municipal groundwater withdrawals. Two sets of discharge constraints were applied. The first scenario constrains discharge to greater than or equal to 80 percent of the 2016 simulated groundwater discharge along Utah Lake. The constraint was met with a total managed aquifer recharge rate of roughly 7,300 acre-feet per year during 2042–56, and 15,600 acre-feet per year during 2057–66. A second scenario constrains discharge to greater than or equal to 90 percent of the 2016 simulated discharge. This constraint can only be met at 8 of the 12 discharge areas along Utah Lake. This required a managed aquifer recharge rate of roughly 10,000 acre-feet per year during 2042–56 and 15,400 acre-feet per year during 2057–66. 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/sir20215010).