Delta and Estuary

We live in geographical areas with many types of landforms and water bodies. However, we are unaware of most of them, what they are called, how they are formed, what ecosystems are part of those landforms or water bodies. We know most about rivers, seas, lakes, and oceans in water bodies and plains, mountains, and plateaus in landforms.

However, more kinds of landforms and water bodies exist. River deltas and estuaries are a few of them. Delta is a landform formed near a river where sediments are deposited. The estuary is a water body that is partially enclosed.

Deltas and Estuaries

River, sea, lakes, and oceans and the main types of water bodies. The most common kinds of landforms are plateaus, plains, and mountains or hilly areas. However, multiple other landforms and water bodies come into existence as a subsequent effect of these main landforms and water bodies. Deltas and estuaries are examples of such landforms and water bodies.

Delta is formed near a river. When sediments from the river keep depositing at a place, a delta is formed. Estuaries are places where the rivers meet the seas. It is a mixture of saltwater and river water.

Delta

A delta is a subsequent water body of a river. Deltas only exist where there is a river. A delta is formed where a river enters another water body through a narrow gap inland. As it enters another water body, the sediments from the river get deposited onto that land. And deltas are formed. 

The size and the shape of the delta are decided by the balance between the river that supplies the sediments and other water bodies that meet the river and cannot carry away the sediments.The evolution of the delta majorly depends on the geometry, size, and location of the receiving basin.

Estuary

Estuaries are formed where two or more items’ rivers are flowing into the sea. The estuary is a partially closed water body. They are the transition of water from the river environment to the sea environment.

A remarkable property of an estuary is having a mixture of freshwater and saline water. They have nutrients from the saline water and the sediments deposited from the freshwater. Both of these together make an estuary one of the most productive ecosystems to exist. They have alternative names such as lagoon, inlets, sounds, etc.

Differences between Deltas and estuaries

Deltas and estuaries are quite different from one another. Following are the points of difference.

Type of Geographical Body:

• The most basic difference between a delta and an estuary is that a delta is a landform while an estuary is a water body
• The estuary is a water body where rivers and sea meet each other
• At the same time, a delta is a landform created where rivers and sea meet each other

Shape

• The shape of an estuary is like a funnel formed at the mouth of the river from where the water moves in and out 
• At the same time, a delta is shaped in the form of a triangle at the mouth of the river

Fertility

• As the delta contains the minerals from the river and also from saline water of the sea, it is highly fertile and provides great productivity for agriculture on nearby land
• The land near the estuaries cannot be considered much productive, and the agricultural yield is not so great

Suitable Activities

• An estuary area is more suited to carrying out fishing activities 
• This is because of the high fertility created by the sedimentary deposit
• As the estuary has saline water as well, it is great to carry out fishing activities

Formation

• The formation of estuaries takes place when the river is encountered with high tide
• Deltas are formed when a river is encountered with a low tide

Areas where they are found

• Estuaries are formed in regions which experience high tides often and rift valleys as well
• Delta is formed in regions which experience coastal plants, and also the tides need to be low in this region

Nature

• The nature of an estuary is transgressive
• The deltas are regressive in nature

Importance

• Estuaries are great wildlife habitats, and even people have settled around them
• Deltas are great for fishing, and hence fishermen are found the deltas exist

Conclusion

There are various types of landforms and various types of water bodies too. We mostly only know about rivers, seas, plains, mountains, and plateaus. However, there are other landforms and water bodies like deltas and estuaries.

Estuaries are formed where two or more rivers meet the sea. Such areas are highly productive as natural habitats for animals. Deltas are formed where the rivers deposit the sedimentary materials that the other water body connected to the river cannot carry. This makes deltas highly fertile for agriculture. Estuaries are more suitable for activities such as fishing.

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