Phosphorus affects surface water as a result of sedimentation. Phosphorus attaches to soil particles. During erosion, soil particles carry the phosphorus into water bodies. Aquatic plants thrive on phosphorus and can grow or spread to levels harmful to desirable fish populations. Large algae blooms result from high levels of phosphorus in surface water.
Sediment is the largest pollutant by volume of Midwest surface waters.
Soil eroded from fields settles in ditches, streams and other surface waters. A build-up of sediment requires dredging to clear the waterway. Sediment increases the turbidity, or cloudiness, of water. Turbidity reduces light penetration, which impairs photosynthesis, alters oxygen levels and reduces the food supply for certain aquatic organisms. Sediment can cover spawning beds, destroying fish populations.