Recharge and Depletion of Ground-Water Supplies

It is widely believed that the water table is declining and that ground-water supplies are being depleted because of deforestation, drainage, improper methods of land cultivation, and pumping from wells. In addition, many fantastic explanations are offered to account for depletion of ground-water supplies. The paper describes the nature of ground-water reservoirs or aquifers, their recharge from precipitation and stream flow, and their discharge through seeps and springs and by evaporation and transpiration. It shows that changes in ground-water levels are caused by climatic changes or by human activities that affect the rates at which the ground-water reservoirs are recharged and discharged. Although additional investigation is needed, there is no reason to believe that changes in ground-water levels due to deforestation, drainage, and land cultivation have been progressive over long periods in most parts of the United States.