Part II Runoff Erosion is the movement of soil from one place to another by wind or water.
Erosion caused by water is the most wide spread problem.
When it rains, the water will either move into the soil, or it will run off, depending on how steeply the land is sloped and whether or not the soil is covered. When soil on a slope is left bare due to drought, crop harvest, cultivation, construction or other soil disturbance, rain falling on that soil can begin moving down hill faster than it can soak in. As the water moves down hill it carries soil with it. The faster the water moves, the more soil is carried. This causes the top soil, the most productive layer, to be carried away.