Develop Estimates of Hydrologic Budget Components
Imes and Emmet (1994) produced a regional groundwater budget determined by a steady-state model simulation for the Ozark system. The Imes and Emmett model consisted of large model cells (uniform spacing of approximately 14 miles on a side) and simulated predevelopment conditions without pumping. Based on the model simulation, 75 percent of the mean annual precipitation that falls on the outcrop area of the Ozark system was removed as evapotranspiration and overland flow to streams. The remaining 25 percent of the mean annual precipitation recharged the aquifer system. Approximately 6 percent of the precipitation (or 22 percent of the total recharge) contributed to the simulated deeper regional flow system. The remaining 78 percent serves to recharge the relatively shallow flow system. Of the net recharge, about 42 percent discharges to rivers, while 36 percent discharges into the overlying water table within the Western Interior Plains confining unit. The remaining 22 percent is thought to discharge to the Cretaceous sands of the Mississippi embayment.
Because of the low spatial resolution and steady-state simulation of the Imes and Emmet model, refinement of the Ozark water budget is needed. A hydrologic budget will be developed for predevelopment and recent (2012 – 2014) conditions for the Ozark system based on the compilation of existing local-scale water budgets from recent groundwater-flow modeling analyses, preliminary regional simulations, and available water-use and climatic data. This information will then be used to quantify the current status of the system-wide groundwater resources.
For more information on the USGS Regional Groundwater Studies, please visit the USGS Groundwater Resources Program.