New Private Wellowner Guide to Groundwater In Pennsylvania- Groundwater and Drinking Water in PA
Potable water is most valuable and under appreciated resource of our planet. Why? Because in many locations, the "aquifer" is hundreds of feet below ground and extends over a vast area that includes multiple municipal and state boundaries. Over 70 percent of the earth's surface is covered with water, but < 0.5 % of this water is usable freshwater resource. All the remainder of the water is salt water. The water on this planet moves through a cycle that is the ultimate solar power system and the cycle is in dynamic equilibrium.
The primary sources of usable water is Pennsylvania include rainwater , stream inflow from other states, surface water (stored in lakes, streams, and ponds), and groundwater. In 1966, it was estimated that Pennsylvanians use approximately 6.6 billion gallons of water per day and there is approximately 80 trillion gallons of groundwater and only 2.5 trillion gallons of surface water.
For Pennsylvania, the annual precipitation ranges from 30 to 60 inches per year with a mean rainfall of approximately 41 inches. Approximately 55 to 60 percent of the precipitation occurs during the warmer months. Of this approximately, 20 inches or more is returned to the atmosphere via evapotranspiration (ET) or evaporation, 12 to 15 inches infiltrates into the groundwater system, and direct runoff accounts for approximately 6 to 12 inches of water. Groundwater storage in Pennsylvania is equivalent to approximately 100 inches of water, but a more conservative estimate is 47 trillion gallons (60 inches), of which, 9 to 12 trillion is naturally discharged to springs, seeps, streams, and lakes. Therefore, groundwater is not only used for drinking water, but the discharge of groundwawter to the surface and near-surface provides the necessary baseflow to support the aquatic habitats in Pennsylvania.
For more information - go to