Describe how a delta forms.

Deltas form where rivers transporting sediment enter a calmer body of water such as a lake or sea and there is a decrease in the energy of the system. The reduction in energy of the flow causes the sediment to settle out of the flow and it is deposited on the lake/sea floor at the river mouth. This process continues and gradually a delta will grow out into the body of water as layer after layer of sediment builds up. There are various types of delta that can form dependent on wether they are, wave, tide or river dominated.