Groundwater recharge sources are precipitation, induced recharge from surface water, and seepage from glacial drift and terraces along the valley wall. A groundwater study conducted in 2011 calibrated an average annual groundwater recharge of approximately 8 inches within the alluvium near the ILRW well field in Clay County (Gannon, 2011). At an average groundwater recharge rate of 8 inches per year, approximately 13 billion gallons per year (bgy) of precipitation would recharge the aquifer. If we classify a severe drought as half the annual precipitation (Gannon, 2006), and we assume this corresponds to an estimated recharge of 4 inches per year (half the average recharge), approximately 6.5 bgy of precipitation recharge enters the aquifer during a severe drought. Much of this recharge is removed from the aquifer through river baseflow and evapotranspiration. The actual rate of groundwater available for use would need to be quantified using hydrographs, analytical methods, and numerical modeling.