A River Runs through It Background
Rivers, creeks, and streams throughout the Chesapeake Bay watershed are fronted by a wide variety of land types. The impact of the land use surrounding the upper portions of the river is felt all the way downstream, influencing the water quality of the river and, ultimately, the Bay.
Perhaps the greatest negative impact results from conditions that contribute to increased runoff, sediment, and nutrient levels in the water. Increased runoff causes erosion and flooding of waterways. The rapid water picks up and spreads pollutants. Erosion and runoff from exposed soil contribute sediment to the water. The sediment blocks the sunlight underwater grasses need to produce the oxygen that benefits other organisms in the water. Increased nutrients cause algal blooms that also block sunlight. Several of the scenarios in this lesson also deal with air pollution and animal waste, another source of increased nutrients.
The most effective method of reducing runoff, erosion, and pollutants entering the water is the maintenance of vegetation along the riverbank. Vegetation serves as a natural filter and slows the flow of runoff. Vegetation also shades the waterway and prevents the water from reaching unhealthy temperature levels. Farmers who practice no-till farming and/or contour plowing help to reduce erosion and runoff. Developers who maintain a vegetated buffer along waterways are helping to reduce the potential runoff of pollutants and sediment. Contractors who use retaining fences also slow down the level of erosion and runoff from building sites.