Alluvium is all the sediment that is deposited by running water. Deltas are formed where running water moves into standing water. The Missouri River Valley has been formed by this slow-moving erosional force. Tributaries are bodies of water which flow into a larger river. These form valleys within a larger valley, leaving hills on each side.
Fluvial landscape is the landscape formed by rivers.
Rivers move back and forth in a snake-like pattern causing erosion and deposition. This may cause the river to become so tightly curved that the river may take a short cut across the corners and create a loop or an oxbow lake. An oxbow lake is the explanation for the creation of Lake Manawa and Carter Lake. Deposition is the process of eroding materials into sediments then depositing them elsewhere. Deltas are areas of built up from soil dumped when a river empties into a lake or ocean.