Alluvial Deposits are unconsolidated sediments that have been deposited by running water. This results in sorting of materials, as large blocks are dropped quickly while smaller materials travel farther before settling out of the water.  Generally, fast flowing water picks up materials and slow flowing water drops them. When a stream or river reaches a terminus (a lake or ocean), the remaining materials are quickly dropped although very fine components may still travel for hundreds of miles before settling.

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