A river current is the water moving in a river. Rivers flow from high points to lower ones and eventually down to a larger body of water. The force of gravity, which makes the water flow downward, creates river currents. A current is the steady, predictable flow of one fluid within the body of another fluid. Fluids are materials capable of flowing and easily changing shape. The most common natural fluid is water. River currents are influenced by the volume, or amount, of water flowing in a river; the river's steepness, called its stream gradient; and a riverbed's topography, including sand bars, basins, rocks, and dams.