It picks up and carries weathered rocks and soils to other places. It also creates many features on the earth's surface. Rivers cause erosion by transporting weathered rock and soil downstream. The Grand Canyon is one spectacular feature that was created by river erosion. Over millions of years, the Colorado River carried weathered sediments away until the mile-deep canyon was created as we know it today.
Floods can cause brief periods of heavy erosion.
Raging waters can carry huge load of rocks, soil and debris. These same waters can deposit soils in wide, flat areas on both sides of the river in the aftermath of a flood. While these flood plains are often very fertile, the flooding potential can make flood plain areas a dangerous place to live and a risky place to grow crops. Runoff first forms tiny grooves called rills to occur. Over time, the rills widen and deepen to form gullies, and the gullies act as channels for runoff.