Running water includes all the water that falls on Earth as rain or snow and then moves downhill under the pull of gravity. Like other agents of erosion running water gets its energy from the sun. The sun lifts water from the surface of the oceans by evaporation.
Winds created by the sun s heating of the atmosphere carry the water vapor over land.
When the water falls as rain or snow and runs back to the sea, it is using the sun s energy to erode the lands. Running water is most effective when flowing in a fast paced river, rather than a slow stream. Fast flowing rivers tend to pick up more pebbles, sand and other materials that cause erosion. They wear away at the river bank and bedrock faster. The river above is a major element of erosion, using cutting tools it breaks away at the bedrock.