What is a Delta Landform?

Where do most rivers lead to —the sea! A river at its source flows fast in a mostly straight path. Before a river gets to its end, its speed is significantly reduced and begins to meander, which means it flows in a very curvy nature.

River flow at its source and end
River flow at its source and end

At the endpoint of a river, there is a wetland in the shape of a triangle when seen from above. The river separates into many smaller channels called distributaries. A distributary form when the speed of the river is so low that the water cannot stay on course and rather, finds its paths to the sea. The low speed of the river also causes it to meander (flow in curves). This sediment deposited wetland where a river meets the sea to feed into it is known as a delta.

A delta is sediment and silt deposited landform formed by rivers in their lower course right at the point where they enter the sea.

A delta is NOT an estuary. An estuary is a body of water found at places where rivers meet the sea, whiles a delta is a landmass. Estuaries have a mix of freshwater from land and some salty seawater from the ocean.

The part of the delta that is influenced by the river’s activity is called the Upper Delta. The other side which is influenced by the ocean’s activity is called the Lower Delta.

A delta forms when water loses its velocity and ability to carry its load (sediments) and deposits them at the bottom of the river. With time, the sediments build up, forming new land. It is key to know that not all rivers have Deltas. Deltas are only possible when the flow of the water is slow enough for silt and sediments to be deposited.

A Delta
A Delta

There are three types of deltas:
Arcuate or fan-shaped delta, Cuspate delta, and Bird’s foot delta.

Some great examples of Deltas include:

1. The Ganges–Brahmaputra Delta in India and Bangladesh is believed to be the biggest delta network in the world.

2. The Mississippi River Delta in the USA. It provides a livelihood for people in that region, including Louisiana in the form of fishing, transport, and refineries. The delta is a habitat for many wildlife.

3. The Nile River Delta, Egypt. The delta begins in the North of Cairo and continues into the Mediterranean sea.