Hydrologic 3

St. Francois Aquifer summary (Imes and Emmett, 1993)-The aquifer can provide wells that deliver 100-500 gallons per minute, but are ordinarily less in yield. Because of the general depth the aquifer has little withdrawal. The St. Francois Mountains are the only recharge area at surface level. Other recharge is believed to occur through leaky confining layers. Close to the mountains, the aquifer discharges to nearby rivers. The dominant dissolved chemical specie are calcium, magnesium, and carbonates. Total dissolved solids are 200-400 mg./l, chloride ≤ 60 mg/l, and sulfate ranges from 30 to 150 mg/l (Imes and Emmett, 1993). Examples of surface streams in the St. Francois Mountains and nearby region are presented in the last section.