What Is Sheet Erosion?

Description

• Sheet erosion is the displacement of large amounts of soil caused by heavy rains or water running off topsoil. It starts when the first raindrop hits the ground. According to Iowa Stormwater Management raindrops "typically fall with a velocity of 20-30 feet per second." This is strong enough to dislodge clods of soil and send them sliding off even a small hill. If rain falls too quickly and the soil is unable to absorb the water, the storm water's erosion process can increase by up to 200 times.

Early Signs of Sheet Erosion

• There are ways to detect early signs of sheet erosion. Even if the area is covered with light vegetation, heavy rainfall causes the soil to form a crust through which air and water cannot enter and this puts the soil at risk. Little clumps of sand and clods of soil are also left behind. Another sign of sheet erosion is the sight of exposed roots, change in soil color when the topsoil has been washed off and the formation of water puddles with soil suspended in them.

Areas at Risk

• Many farmers' fields are at risk for sheet erosion since some of these fields lie fallow and are bare due to overgrazing by cattle. Fallow means that the land is left uncultivated. And when the soil is left unprotected, it is vulnerable to water runoff. Bare hillsides and bare ground in urban back or front yards are also potentially at risk of losing their topsoil.

Action to Stabilize Sheet Erosion

• The best way to prevent sheet erosion is to ensure that the soil is covered with vegetation. Bare soil can easily be washed off. Perennial plants, grass and shrubs are all good at holding the soil in place. Farmers should rotate crops so that land need not be left to lie fallow, and cattle grazing should be controlled so that the land is not grazed bare.