Monday, April 12, 2010

Non-Point Source Pollution and Best Management Practices

Non-point source (NPS) pollution is a major factor impacting the quality of the water supply. The rate at which diffuse sources of pollution are generated and delivered to water resources is greatly affected by human activities and natural processes. These pollutants are transported to surface water bodies by runoff, which results from precipitation or snowmelt (Leeds et al., 1993). Storm water is part of the natural hydrologic process; however, human activities, especially urban development and agriculture, cause significant changes in patterns of storm water flow and infiltration and the type and quantity of contaminants carried from land into receiving waters.

Urban storm water runoff includes all flows discharged from urban land uses into the storm water systems and receiving waters. Urban runoff includes runoff from landscape irrigation, dewatering, and water line and hydrant flushing as well as the wet-weather storm water runoff. Water quality can also be affected when runoff carries sediment and other pollutants such as oil and grease, pesticides, paints, cleaners and other products associated with modern life into streams, wetlands, lakes, estuarine and marine waters, or groundwater.

Agricultural activities that cause NPS pollution include confined animal facilities, grazing, plowing, pesticide spraying, irrigation, fertilizing, planting, and harvesting. The major agricultural NPS pollutants that result from these activities are sediment, nutrients, pathogens, pesticides, and salts. Agricultural activities also can damage habitat and stream channels. Agricultural impacts on surface water and ground water can be minimized by properly managing activities that can cause NPS pollution, by utilizing good environmental stewardship.

Good environmental stewardship means using land and animals in a way that protects and improves the environment. Environmental stewardship begins by evaluating the farm to identify likely pollution sources and their possible effect on the surrounding environment. Overgrazing pastures; applying too much manure; giving animals free access to streams, ponds, wetlands, or marshes; mismanaging manure; and allowing excessive erosion can reduce water quality. The type, size, and numbers of animals affect the amount of management required for your farm. Kate Norris of Prince William Soil and Water Conservation District has put together a series of articles outlining the basic techniques to use to minimize environmental impact from a horse property. Many of these techniques can be used with any small scale livestock farm or hobby horse farm.

Overstocking causes most of the water quality damage on small-scale livestock farms and hobby horsefarms. It occurs when too many animals are kept on too few acres. Overstocking can strip areas of pasture, increasing polluted runoff. On farms where animals are confined and manure is collected, overstocking often leads to large amounts of manure that must be managed. So called Best Management Practices, BMPs, range from making simple changes to building structures that hold manure, but they in total add up to less run-off of pollution. They can be comprehensive and consider how the parts of the farm are related. BMPs are meant to be practical and easy to implement. They are intended to be modified to fit the type of operation, and the environmental and geological factors specific to the site. Unbelievably enough, the Soil and Conservation Districts throughout the nation are there to help you manage your properties for free.
BMPs minimize inputs of fertilizers, pesticides, labor, etc. to achieve a desired level of course performance and quality while protecting the environment. BMPs are designed to benefit water quality while maintaining or even enhancing agricultural production.Agricultural BMPs are practical, cost-effective actions that agricultural producers can take to reduce the amount of pesticides, fertilizers, animal waste, and other pollutants entering our water resources. The most recent National Water Quality Inventory reports that agricultural nonpoint source (NPS) pollution is the leading source of water quality impacts to surveyed rivers and lakes, the third largest source of impairments to surveyed estuaries, and also a major contributor to ground water contamination and wetlands degradation. Good environmental stewardship of these properties can go a long way in making agriculture sustainable.

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