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Clean Water Act of 1972
The objective of the Clean Water Act (CWA) is “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters”. This act establishes national goals concerning the health of United States surface waters, which include a complete elimination of pollutant discharge into navigable waters by 1985, the complete prohibition of toxic pollutants in toxic amounts, and the establishment of programs to control both point and nonpoint source pollution.
While individual states and the EPA have successfully reduced some point source pollution, nonpoint source pollution is still a major water quality issue.
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Point source versus nonpoint source pollution
The Environmental Protection Agency’s (EPA) CWA website defines point source pollution as: pipes or man made ditches that discharge pollutants into US waters. This includes discharges from municipal sewage plants and industrial facilities, but also collected storm drainage from larger urban areas, certain animal feedlots and fish farms, some types of ships, tank trucks, offshore oil platforms, and collected runoff from many construction sites.
Nonpoint source pollution is any pollution that isn't a point source. It reaches surface waters as a direct result of rainfall or snowmelt moving over and through the ground and is sometimes referred to as “poison runoff.” When it rains, water accumulates on man-made surfaces such as roads, roofs and parking lots -- hard surfaces that prevent water from soaking into the ground. Runoff from the land that flows into other bodies of water -streams, rivers and lakes - carries many contaminants including sediment, phosphorus, nitrogen, toxic metals, herbicides and pesticides, organic material, oil compounds, and bacteria. Roadways release oil and grease, tailpipe emissions, and other toxics from motor vehicles. Lawns allow drain-off of fertilizers and animal waste. Construction sites release quantities of mud which contribute to erosion. Commerical and industrial areas can be a source of heavy metals.
In addition to polluting the water, runoff creates havoc when it floods streams or lakes. The increased water flow erodes stream banks, destabilizes stream contours and changes depths. Accumulated runoff eventually finds its way into large bodies of water like the Great Lakes, Mississippi River, Chesapeake Bay, Long Island Sound, Puget Sound and the Gulf of Mexico and causes even greater problems.
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Proposed Changes for Stormwater management
- The National Research Council committee recommended that EPA adopt a watershed-based permitting system that would encompass all discharges -- including stormwater and wastewater -- that impact waterways in a particular drainage basin, rather than having many individual permits.
- Additional adjustments could include bringing construction and industrial sites under the jurisdiction of their associated municipalities, referred to as "integration" by the NRC committee.
- Because the area being appropriated for urban land use is growing faster than the population, stormwater management also needs to consider land use management. Future land development and potential increases in stormwater must be considered in new regulations.
- The NRC committee recommended the program focus less on chemical pollutants and more on the increased volume of water. In urban areas, stormwater flows rapidly across the land surfaces and arrives at streams in short, concentrated bursts of high water discharges, which in turn increases streambank erosion and accompanying sediment pollution of surface water.
- Other suggestions include: conserving natural areas, reducing hard surface cover such as roads and parking lots that channel stormwater into waterways, and retrofitting urban areas to hold and treat stormwater.