Rivers

A river is a physical landform that conducts (primarily fresh) water, sediment, and nutrients downslope under gravity from topographically higher land toward depressions at a lower elevation, most often into bodies of water. The total volume of water in the global hydrosphere that can be found in rivers is miniscule (0.0001%), yet rivers are a key part of the hydrologic cycle, conducting water delivered to the landscape via precipitation, springs (groundwater), or glacial meltwater to oceanic environments. The river channel, or depression of varying width and depth, contains water at least sporadically, if not constantly, depending on its geography. A river's physical character is a direct result of its local [Page 2472]climatic and geologic conditions, which may vary with distance along its course. As both ...