Many nonpoint sources are linked to land use practices including agriculture, forestry, mining, transportation, landfills, and construction. Improper land management can increase the amount of pollutants that are carried in runoff after heavy rains. Agricultural production, dairy and feedlot operations, construction, and natural processes can all produce increased sedimentation.
Sediments also bind other pollutants that are transported in runoff.
Excess amounts of sediments can make rivers and streams more turbid and can reduce the volume of water that can be stored behind dams. Some sedimentation and erosion also occurs naturally. However, too little or too much sediment can destroy fragile ecosystems. The TWC views sediments as nonpoint source pollutants only when they exceed naturally occurring levels. The TWC recognizes contaminants transported by sediments as nonpoint source pollutants.