Environmental Engineering Reference
In-Depth Information
We did not list raw sewage, because for the most part raw sewage is no lon-
ger routinely dumped into our nation's wells or into our soil. Sewage treat-
ment plants effectively treat wastewater so that it can be safely discharged
to local water bodies. In fact, the amount of pollution being discharged
from these plants has been cut by over one-third during the past 20 years,
even as the number of people served has doubled. Yet, in some areas raw
sewage spills still occur, sometimes because a underground sewer line is
blocked, broken, or too small or because periods of heavy rainfall overload
the capacity of the sewer line or sewage treatment plant so overflows into
city streets or streams occur. Some of this sewage finds its way to ground-
water supplies.
Summary
The best way to prevent groundwater pollution is to stop it from occurring
in the first place. Unfortunately, a perception held by many is that natu-
ral purification of chemically contaminated ground can take place on its
own—without the aid of human intervention. To a degree this is true; how-
ever, natural purification functions on its own time, not on human time.
Natural purification could take decades, perhaps centuries. The alterna-
tive? Remediation. But remediation and mitigation don't come cheap. When
groundwater is contaminated, the cleanup efforts are sometimes much
too expensive to be practical. The USEPA established the Groundwater
Guardian Program in 1994, which is a voluntary approach to improving
drinking water safety. Established and managed by a nonprofit organiza-
tion in the Midwest and strongly promoted by the USEPA, this program
focuses on communities that rely on groundwater for their drinking water.
It provides special recognition and technical assistance to help communi-
ties protect their groundwater from contamination. Groundwater Guardian
programs have been established in nearly 150 communities in 34 states
References and Recommended Reading
Chapelle, F. (1997).
The Hidden Sea: Ground Water, Springs, and Wells
. Tucson, AZ:
Geoscience Press.
Chilton, J. (1998). Dry or drowning.
Our Planet
, 9(4).
Edwards, B.D. and Evans, K.R. (2002).
Saltwater Intrusion in Los Angeles Area Coastal
Aquifers: The Marine Connection
, Fact Sheet 030-02. Washington, DC: U.S.
Geological Survey.
