Difference Between Delta and Estuary

What is Delta?

Geography tells us that when a river is closer to falling into a larger body of water, such as an ocean, its moving speed starts to slow down. As a result of this, the sediments that come traveling in the river get deposited at the mouth of the river. When a considerable amount of sediments is deposited at the river mouth, a delta is formed.

A delta is, therefore, essentially a landform that is created by the accumulation of sediments at the river mouth. There are many types of deltas: fluvial-dominated deltas, Gilbert deltas, wave-dominated deltas and tide-dominated deltas. The standard shape of a delta is like a triangle.

Deltas have a special role to play in nature, especially in the ecosystem. To mention a few, they supply rich and fertile land for agriculture, deltas are helpful in blocking pollutants and other contaminants, and deltas provide habitat to wildlife.

Alongside advantages, they have some demerits as well. Erosion is a key component in the making of a delta; therefore, it comes with adverse effects of erosion. Deltas make it hard for ships and boats to move. When such deltas are occupied by the homeless, the pollution rates increase.

What is Estuary?

An estuary is a place where the river meets the ocean. It is the exact point where freshwater and oceanic water intermix with each other. Consequently, a kind of water is made, called brackish water. An estuary is a funnel-shaped area.  

There are four types of estuaries: fjord estuaries, tectonic estuaries, bar-built estuaries, and coastal plain estuaries. Some notable estuaries are the Hudson River, NY, the Thames River, the Seine River, and the Narragansett Bay.

The first one is created by massive glaciers. The second type is created by the rifting of the Earth’s surface. The third one is formed by the rise in sea levels. The fourth one is developed by the protection of a sandbar.

Estuaries have a lot of benefits for humans. They provide an eco-friendly space for the living of people by offering freshwater and unpolluted air. Since they are located near oceans and rivers, they provide excellent trade routes. 

Difference Between Delta and Estuary

  1. Deltas are formed by the accumulation of sediments at the river mouth, whereas estuaries are wetlands that emerge along the coast where a river and ocean converge. 
  2. Deltas look as if they are pieces of land, whereas estuaries give the look of a wetland.
  3. Deltas have a triangular shape, whereas estuaries are funnel-shaped.
  4. Deltas are conducive to agriculture, whereas estuaries are good for marine activity.
  5. Deltas are made by low-tidal rivers, whereas estuaries are made by high-tidal rivers.

Comparison Table Between Delta and Estuary

Parameters of ComparisonDeltaEstuary
FormationDeltas are formed at the river mouthEstuaries are formed along the coast
Necessitating TideExperts believe that deltas are created by the rivers with low-tidal featureExperts believe that deltas are created by rivers with high-tidal feature
ShapeThe shape of a delta is necessarily triangularThe shape of an estuary is generally funnel
Useful ForDeltas are highly beneficial for agriculture Estuaries are important marine life centers
Material StateThe apparent state of the delta is that of a landformAn estuary is more of a wetland along the coast


  1. https://search.proquest.com/openview/681805fc99ea9f9229833a207dcf8302/1?pq-origsite=gscholar&cbl=18750&diss=y
  2. https://tamug-ir.tdl.org/handle/1969.3/24383