The saturated soil is heavier and may also be lubricated by the water. This can also cause the soil to move downslope as a debris flow or mudslide. Return to top Slope Erosion and Drainage Surface water flow can cause erosion of soils on the crest and face of your waterfront slope. Usually, the most severe erosion occurs where surface water flows are concentrated. The steeper the slope angle and higher the slope, the greater the potential is for erosion.
Some soil types are more erodible than others.
For example, soils such as sand and gravel are more prone to erosion than are silt and clay. However, once silt and clay are disturbed, they are highly erodible. Erosion can also cause soil on adjacent slope areas to become steeper to the point that they are susceptible to landsliding. Surface water often causes severe erosion to coastal slopes where pipes are allowed to discharge onto the slope. If this process continues, the soil erodes until the pipe no longer directly discharges onto the slope.