5. Enhanced Soil Erosion and Sediment Load
Natural riparian zones help to trap soil eroding from lands adjacent to rivers. Loss of natural riparian zones results in more soil entering riverways by erosion. The amount of sediment a river carries is proportional to water velocity in the river. Because major rivers of the Midwest have been straightened, deepened, and artificially confined to narrow channels, water velocity and hence sediment load have increased. More and more precious topsoil from Midwest farms is being carried out into the Gulf of Mexico.