Several things happen to the precipitation that reaches land. Some of it evaporates. In cold areas, snow and ice can remain on the ground for short or long periods before eventually melting. Rainwater soaks into the ground or runs along the surface in rivers and streams. Some collects in lakes and other bodies of standing water, but most finds its way back to the oceans. Rainwater that is unable to soak into the ground and that moves over its surface is called runoff. This moving water generally causes erosion (process by which materials are broken into smaller parts and moved) of the surface it flows over.