Rainfall and runoff is a water erosion problem also known as splash erosion. This is the first stage in the erosion process. The impact of rainfall drops on the soil surface can break down soil aggregates as the impact of falling raindrops breaks up the topsoil. This erosion is caused by long lasting and less intense storms. Runoff can occur whenever there is excess water on a slope that can’t be absorbed into the soil or trapped on the surface.
The method used to prevent erosion from raindrop splash erosion is stabilization.
Temporary and permanent vegetation, sodding, mulching, compost, blankets, and rolled erosion control products absorb the impact of raindrops and protect the ground surface. Therefore, stabilizing a surface protects the ground from raindrop erosion. The decreased infiltration results in more water running off and carrying away particles from the surface is called sheet erosion. It is caused by the force of raindrops impacting on bare soil. This process is degenerated in four ways, compression of the soil, crushing and shearing stress, projection of elementary particles, and noise of the impact of the drops.
The potential for sheet erosion is dependent on the soil type, velocity, and quantity of flow over the surface, long slopes, steep slopes, and slopes that carry higher volumes. Gully erosion occurs when water is channeled across unprotected land and washes away the soil along the drainage lines. Causes of gully erosion are a history of poor ground cover due to clearing decimation by fire or rabbits.
Seasonal and cyclic drought, concentrated runoff from steep lands, unstable soils in drainage lines, intense rainfall, elevated runoff caused by factors such as low levels of tree cover and poor soil infiltration.