THREATS TO CROUNDWATER
With all of the rain we have had lately we have had ample opportunity to watch the water cycle at work renewing earth’s fresh water supply. Pure water molecules separated from salt and other substances fall as precipitation. We have observed rains that run off over the surface of the land filling our streams, rivers, and lakes. What we cannot observe is how water infiltrates the soil and runs off underground. Those who have studied the hydrologic cycle tell us that water saturates soil and rock and flows underground finally emptying into a surface water body. Under some conditions water from rivers or streams can move into groundwater.
The flow of water from the surface through groundwater depends on the qualities of rock layers underneath the soil and varies considerably from place to place. In northwest Illinois and the whole Driftless area surrounding the upper Mississippi River, there is considerable fractured rock, sand, and gravel below the surface soil. This can be observed where roadways have been built by cutting through rock layers or where rock is quarried. Under these conditions rain/melting snow can infiltrate the ground - sometimes to great depths - and flow as groundwater great distances. Community or private wells that we use for drinking water draw from groundwater.
Human activities create many challenges to protecting water quality. Appropriate planning, engineering, management, and treatment are vital. Some threats to our drinking water are:

• Parking lots, streets, roads, and storm sewers that allow water flowing over them to carry with it sediment, trash, and chemicals directly to a body of water.
• Buildings and paved areas that change the direction and rate of the water flow.
• Construction sites, city streets, and farm fields that allow sediment to run off with the water.
• Urban lawns, gardens, and croplands that have fertilizers and nutrients applied that may be away by run off.
• Public waste systems, individual septic systems, and livestock facilities, large or small, that add pollutants to run off.
• Pest and weed control that adds chemicals to run off.
• Bridge, road, and building construction that alters natural drainage patterns.
• Industry and mining that adds waste and other chemical byproducts to the environment.

All of these activities are important to us and our way of life, yet they impact the quality of our water supply. Eliminating these activities may not be a choice. Managing them must be a choice. Each of us can manage our own activities in the best interest of water quality. We can support and encourage cooperative efforts to promote good management practices that can help conserve water and protect and restore water quality while allowing for sustainable economic growth and development. To get help contact your Soil and Water Conservation District.

Della Moen, Earth Team Volunteer, NRCS/Stephenson Soil and Water Conservation District, an equal opportunity provider and employer, 11/25/09 for publication on 11/28/09 in the Journal Standard, Freeport, Illinois) Della can be reached at info@stephensonswcd.org