Dynamics of diffuse pollution from US southern watersheds

To understand the effects of diffuse pollution information on the source of pollutants, quantities in transport, mode of transport, transient nature o f the pollution event, and most importantly, a consideration of remediation efforts need to be known. For example, water quality research in the Yazoo Basin uplands in Mississippi has shown sediment loads from a conventional- till upland soybean watershed to be about 19,000 kg/ha/yr, and responsible for 77-96% of P and N in transport. In contrast, sediment loads from a comp arable no-till soybean watershed were only 500 kg/ha/yr, transporting about 31% of P and N in transport. Sediment loads from a nearby forested area we re low, about 200kg/ha/yr, but responsible for about 47-76% of P and N in t ransport. Transient pollution events are responsible for the transport of l arge quantities of sediment, nutrients, and pesticides; in some storm event s nearly the annual load. Best management practices (BMPs) must be designed to remediate diffuse pollution and the transient nature of pollution event s which can have a profound effect on tile ecological health of steams and reservoirs. Published by Elsevier Science Ltd.