Wilkes University Environmental Education, Training Monitoring

Wilkes University
Center for Environmental Quality
Environmental Engineering and
Earth Sciences
Pennsylvania Groundwater

A Brief Explanation
THE Water Cycle, Groundwater Resources, Water Wells and 
Drinking Water Supplies -A  Pennsylvania Perspective

Drought Types - Water Conservation
artesian, well, water, artesians, springs, drinking

A flowing artesian well- 
Free Water NO Pumping Needed

Clean water is one of the most valuable and under appreciated resource of our planet.  Approximately 70 percent of the earth's surface is covered with water, but only a small fraction of this water is fresh water that is actually available for consumption and productive use.  Because of the unique properties of water, a dynamic cycle, known as the Hydrological Cycle, has developed on this planet.  This cycle provides for the continuous movement, transformation, and remediation of  water as it most through a series of solid, liquid, and vapor phases.  One of the most confusing parts of this cycle is when the water becomes classified as groundwater.  This is because it is not easy to visualize the actual flow and transformations (chemical and biological) that is going on as the water moves through the soil and rock. 

The primary sources of 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.

Because of the rural nature of Pennsylvania, groundwater provides approximately 85 percent of the water used for human consumption, but because it is difficult to set how water moves through the soil, unconsolidated  material (sand and gravel) and bedrock.  For some homeowners, they believe that the groundwater comes from a vast underground lake or from underground streams that come from Canada, Vermont, or even Maine.  Even through there is a large database of information on groundwater in Pennsylvania, it still is difficult to really document the total available resource and actual movement and quantity without implementing a very elaborate system of monitoring wells, observation points, and background water quality data.

The hydrologic cycle describes the constant movement of water above, on, and below the earth's surface. As part of this cycle, water is transformed  between liquid, solid and gases states.  Condensation, evaporation and freezing of water occur in the cycle in response to the earth's climatic conditions.  Figure 1 presents components of the hydrologic cycle that directly affect Pennsylvania.

aquifer, aquitard, hydrological cycle, rain, saturated zone, unsaturated zone, evaporation, evaportranspiration, infiltration, well drilling

Figure 1. Components of the Hydrologic Cycle.

The hydrologic cycle begins with water evaporation from the earth's soil, plant and water surfaces to form water vapor. The energy required to evaporate water is supplied by the sun.  The vast majority of evaporation occurs from the oceans.  It is estimated that 39 inches of water annually evaporate from each acre of ocean (Water of the World, US Geological Survey).   Water vapor is drawn into the atmosphere by temperature gradients and can be transported over hundreds of miles by large air masses.  When water vapor cools, it condenses to form clouds. As water condenses within clouds, water droplets increase in size until they fall to the earth's surface as precipitation such as rainfall, hail, sleet or snow.

Approximately 50 to 90 percent of the water that falls to the earth's surface enters the soil.  This water can become groundwater but most of it evaporates from the soil surface, used by vegetation via evapotranspriation, or flows to streams and springs as interflow. Water that passes through the root zone may continue to move downward to reach the groundwater. In soils with fragipans, clay pans or other low permeable strata of a limited extent, this water may create a seasonal high or perched water table.   The distance water has to travel to reach groundwater can range from a few feet to hundreds of feet. Water movement toward groundwater may take hours or  years, depending on the depth to the aquifer and the characteristics of the unsaturated zone.

Once in the groundwater, water will slowly move to discharge points which may include: springs, streams, lakes, wetlands, or even the ocean.  Groundwater moves slowly within the groundwater aquifer, often remaining in storage for 100s of years.

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 is returned to the atmosphere via evapotranspiration 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 60 inches of water or a conservative estimate of  over 47 trillion gallons, of which, 9 to 12 trillion is naturally discharged to springs, seeps, streams, and lakes. 

During periods of drought water supplies become very low. Water-use restrictions are set for communities in order to preserve water. In this situation water can only be used for drinking and sanitation purposes and not for tasks that include washing cars and watering lawns. Here are 19 ways to help conserve water:

  1. Install water saving fixtures on plumbing fixtures.
  2. Flush your toilet as little as often.
  3. Do not dispose tissues and other trash in the toilet.
  4. Make sure that the toilet does not leak. To check for this add food coloring to the tank and check for discoloration of the bowl.
  5. Fix a leaking faucet as soon as possible.
  6. Fill a container with water and let dishes soak in it instead of rinsing them with running water.
  7. Don’t water your lawn or wash your car.
  8. Bath less often or shower. Instead of taking a bath take a shower.
  9. Use a glass filled with water to rinse your mouth when brushing your teeth. This will eliminate the use of running water.
  10. To obtain cold water, keep a bottle of water in the refrigerator instead of running the faucet until you get cold water.
  11. Don’t pre-wash dishes if you have an automatic dishwasher.
  12. Create a compost pile instead of using your garbage disposal unit.
  13. Collect rainwater for watering the lawn and garden.
  14. If your shower has a mixing faucet that gets water to a certain temperature, turn the shower off when lathering your body with soap.
  15. When shaving use a washbowl to rinse off your razor. Use an electric razor.
  16. Use a brush, clothe or your hand to remove particles of dirt instead of using the force of the water when washing dishes.
  17. Allow small children to bathe in the same bath tub.
  18. Use disposable diapers instead of reusable diapers. This will eliminate use of the washing machine to clean them.
  19. Reuse kitchen drain water to water plants or to recharge your toilet tank.

If you have a water conservation tip or would like to add a link on water conservation, please send your request to brian.oram@wilkes.edu - Send your tip or link to me.

The Center for Environmental Quality at Wilkes University is available to elementary schools and non-profit groups in NEPA for discussions on groundwater quality, groundwater flow, well construction, and water quality related issues.  We are happy to participate in workshops, conferences, and other education outreach programs.  If you are interested, please email brian.oram@wilkes.edu

More Information on PA Groundwater
See also the Glossary of Terms
 USGS Drought Monitoring in US- Great Site

For More information about the Environmental Quality Center, please contact:

 Attn: Mr. Brian Oram, Professional Geologist (PG)
Laboratory Director
Wilkes University
Environmental Engineering and Earth Sciences
PO Box 111
84 West South Street
Wilkes-Barre, PA 18766

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