River mouth facts for kids

The river mouth is the special place where a stream or river finishes its journey and flows into a bigger body of water. This bigger body of water could be another, larger river, a lake, an ocean, or even a sea. It's like the end of the road for the river's water!

What Happens at a River Mouth?

When a river reaches its mouth, several interesting things happen. The river's speed usually slows down a lot. This causes it to drop all the sediment (like sand, mud, and tiny rocks) it has been carrying along its journey. This dropped sediment can build up over time, creating new landforms.

The water from the river also mixes with the water from the larger body. If the river flows into the ocean, fresh river water mixes with salty ocean water. This creates a unique environment called brackish water, which is a mix of fresh and salt water.

Types of River Mouths

Not all river mouths look the same. Their shape depends on things like the amount of sediment the river carries, the strength of ocean tides and waves, and the shape of the coastline.

River Deltas

A delta is a landform that looks a bit like a triangle or a bird's foot. It forms when a river carries a lot of sediment and drops it at its mouth. The river often splits into many smaller channels, called distributaries, as it flows across the delta and into the sea. Deltas are usually very flat and fertile, meaning they are good for farming.

• Example: The Nile River in Africa has a famous delta where it meets the Mediterranean Sea.

Estuaries

An estuary is a partly enclosed coastal body of brackish water. It forms where a river's mouth meets the ocean, and the river's flow is affected by ocean tides. Instead of building up a lot of new land, the river water mixes with the sea water in a wide, funnel-shaped area.

• Example: The Thames River in England flows into an estuary before reaching the North Sea.

Other Types

Sometimes, a river might flow directly into the sea without forming a large delta or estuary, especially if the coastline is steep or if strong ocean currents carry the sediment away.

Why River Mouths Are Important

River mouths are very special places for many reasons:

• Wildlife Homes: They are home to a huge variety of plants and animals. Many fish, birds, and other creatures depend on the unique mix of fresh and salt water, and the rich nutrients found here. They are often important breeding grounds and nurseries for young fish.
• Natural Resources: The fertile lands of deltas are great for agriculture, allowing people to grow crops. Estuaries are often rich fishing grounds.
• Human Activities: Many cities and ports are built near river mouths because they offer good places for ships to dock and trade. They have been important for transportation and settlement for thousands of years.

Famous River Mouths

• The Amazon River Mouth: The Amazon River in South America has the largest discharge of any river in the world. Its mouth is so wide that it's sometimes hard to tell where the river ends and the Atlantic Ocean begins!
• The Mississippi River Delta: In the United States, the Mississippi River forms a large delta as it enters the Gulf of Mexico. This delta is a vital area for wildlife and human activities.
• The Ganges River Delta: The Ganges River in Asia forms a massive delta with the Brahmaputra River, creating the largest delta in the world. It is a very densely populated area.

Related pages

• Confluence
• Reservoir
• River delta
• Estuary

Images for kids

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  Aerial picture of the Ebro river's mouth as it enters into the Mediterranean Sea by the Ebro's delta.

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  Aerial picture of the Kinburn Spit.

See also

In Spanish: Desembocadura para niños