Loudoun Watershed Watch - Overseeing the Water Resources of Loudoun County, VA


Loudoun Watershed Watch Overseeing the Water Resources of Loudoun County, VA
	Agricultural Impacts In the U.S. agriculture runoff accounts for approximately 60% of the nonpoint source pollution. Inadequate crop and livestock farming practices add significant amounts of nutrients and sediments to the runoff that enters the streams. Problems result from converting forested floodplains and wetlands to agricultural land; overgrazing; allowing livestock to trample riparian vegetation, stream banks, and stream habitats; and not providing a tree and shrub buffer between crops and waterways.
	Sediments -- Crops and cattle farming practices can be unhealthy for streams. If crops are planted too close to streams or cattle have unlimited access the result is often excessive erosion and high levels of sediment in streams. Not only does sediment smother the habitat of bottom-dwelling aquatic organisms, the effects are felt all the way up the food chain.	Sediment bank NF Goose Cr.
	Nutrients -- Fertilizers and manure provide nutrients that allow algae (simple aquatic plants) to grow quickly. Algae use oxygen from the water at night during respiration. Oxygen is also used by bacteria that feeds on or decomposes dead algae. The oxygen that is required for decomposition is called biological oxygen demand or BOD. When the dissolved oxygen (DO) in stream water gets depleted or fluctuates widely due to an overabundance of algae in a stream, it creates stressful or unlivable conditions for many aquatic insects. Once again, the effects are felt throughout the local ecosystem.	Algae on rocks in Beaverdam Run
	Fecal Pollution -- Wastes from warm-blooded animals including human sewage, and livestock release disease-causing organisms into streams. Fecal coliform bacteria are used to indicate the potential presence of human pathogens and the likelihood of a public health threat. Higher concentrations cause greater public health concerns. DEQ considers recreational waters to be impaired or unsuitable for use when water samples collected over a 2-5 year period are greater than an average of 126 E. coli colonies per 100 ml of sample (EC MFN/100ml).	Cows in Limestone Branch
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