Deltas

Definition of River deltas: The fan-shaped mouth of a river, formed by several distributary channels. This is the common definition for River deltas, other definitions can be discussed in the article

Notes

River deltas are formed when the supply of sediments to the coast by a river is faster than they are dispersed by waves, tides and the associated currents. They are the result of depositional and erosional processes under the influence of currents, waves and tides. Because of their different morphologies, often a distinction is made between river-dominated deltas, wave-dominated deltas and tide-dominated deltas.

Mahakam delta (Borneo). River-dominated delta. Landsat image.

Hooghly estuary (India). Tide-dominated delta. Sentinel image.

Ebro delta (Spain). Wave-dominated delta. Google Earth image.

Definition of Flood and ebb tidal deltas: Flood tidal deltas are sedimentary bodies deposited by tidal flood currents. Ebb tidal deltas are sedimentary bodies deposited by tidal ebb currents. This is the common definition for Flood and ebb tidal deltas, other definitions can be discussed in the article

Notes

Flood tidal deltas and ebb tidal deltas are generally present at the inshore and offshore sides (respectively) of tidal inlets of estuaries and tidal lagoons.

Vlie inlet in the Western Wadden Sea (Netherlands). Flood shoals (tidal flats) are shaped by tidal flood currents. Ebb shoals are shaped by tidal ebb currents and waves.

Belize lagoon inlet, with ebb and flood shoals.

See also

• Morphology of estuaries
• Wave-dominated river deltas
• Characteristics of sedimentary shores