06/19/2012 09:53

Even if it interferes with our outdoor plans, we need rain. Our streams, rivers, and lakes are obviously maintained by precipitation. Out of site but equally important, melting snow and rain infiltrate the surface of the land and are the source of water for trees, lawns, gardens, crops, and our drinking water.

We also need to protect water quality. We are apt to think that the water we see on the surface is somehow totally separate from the groundwater we count on for drinking. Groundwater and surface water are fundamentally interconnected. In fact, it is often difficult to separate the two because they “feed” each other. By being careful about what we put on the surface of the ground and under the surface of the ground we can protect water quality for ourselves and others. We can also support regulations and community efforts to protect recharge areas and wells.

The Conservation Technical Information Center (CTIC) explains the surface and groundwater connection this way:

  • Groundwater feeds surface water. One of the most commonly used forms of groundwater comes from unconfined shallow water table aquifers -- underground layers of porous rock (sand, gravel, limestone) that are saturated from above by infiltration or from structures sloping towards them. They also interact closely with streams, sometimes flowing water into a stream or lake and sometimes receiving water from the stream or lake. Groundwater can be responsible for maintaining the hydrologic balance of surface streams, springs, lakes, wetlands, and marshes.
  • Surface water feeds groundwater. Approximately 5-50% (depending on climate, land use, soil type, geology and many other factors) of annual precipitation results in groundwater recharge. In some areas, streams literally recharge the aquifer through streambed infiltration. Left untouched, groundwater naturally arrives at a balance, discharging and recharging depending on hydrologic conditions.

            Maintaining good freshwater quality, both surface water and groundwater, depends on identifying sources for contamination.

  • When point sources can be identified, such as sewage treatment plants, large injection wells, industrial plants, livestock facilities, landfills, etc., they are regulated by the state water quality agency and the USEPA through a permitting process.
  • Other sources are widespread, seemingly insignificant amounts of pollutants, such as septic systems, agriculture, construction, grazing, forestry, recreational activities, careless household waste management, lawn care, parking lot, and urban runoff. These nonpoint sources are often not required to have a permit. Individually, each may not be a serious threat, but together they may be a significant threat to water quality.

Information for this article was taken from Know Your Watershed web pages on the CTIC website: www.ctic.purdue.edu, Effects of Human Activities on the Interaction of Ground Water and Surface Water.

Della Moen, Earth Team Volunteer, NRCS/Stephenson Soil and Water Conservation District, an equal opportunity provider and employer, 06/13/12 (for publication on 06/16/12 in the Journal- Standard, Freeport, Illinois)  Della can be reached at info@stephensonswcd.org