How Rivers Form and Where They Flow

How Do Rivers Start?

Rivers begin their journey high in the mountains or highlands, where rainwater and melting snow collect on steep slopes. This water doesn't stay still—gravity pulls it downhill, and as more water joins, tiny streams form. These small streams merge together, getting bigger and bigger, until they become powerful rivers flowing toward the sea.

The River's Journey Downhill

Once a river forms, it follows a very predictable path. Water always flows downhill because of gravity, so rivers carve channels through the landscape as they travel. In the upper course (near the mountains), rivers are narrow, fast, and rocky. As the river moves into middle and lower courses, it slows down, becomes wider, and picks up more water from tributaries—smaller rivers and streams that flow into the main river.

Over time, flowing water can shape the landscape dramatically, carving out deep valleys and gorges as it erodes rock and soil. The river also carries sediment—tiny pieces of rock and soil—which gives water its brownish colour during heavy rainfall.

Where Do Rivers Flow To?

Almost all rivers eventually reach the sea or ocean. Some rivers flow into lakes instead, which act as natural reservoirs. The place where a river meets the sea is called the mouth of the river. At the mouth, rivers often form deltas—wide, flat areas where the river splits into many channels before emptying into the sea.

A few rivers flow into deserts and dry areas, where they disappear into the ground or dry up completely. But most rivers follow the same basic pattern: they start in mountains, flow downhill gathering water, and end in the sea. This endless cycle keeps repeating as new rainwater falls and continues the journey all over again.

Where Do Rivers Start?

Rivers begin high up in mountains. Rain and melting snow flow down the steep slopes. Small streams form and join together. They get bigger and bigger. Eventually they become rivers.

How Rivers Flow Downhill

Rivers always flow downhill because of gravity. The water carves a path through the land. Near the mountains, rivers are thin and fast. They rush over rocks.

As rivers travel further, they get wider and slower. Small streams join the main river, making it bigger. The river carries soil and rocks with it. This makes the water look brown sometimes.

Where Do Rivers Go?

Rivers flow all the way to the sea. Some flow into lakes instead. At the sea, the river ends. This place is called the mouth of the river.

Some rivers make a special shape called a delta where they meet the sea. The river splits into many smaller rivers. Then they all flow into the ocean together.

This keeps happening forever. More rain falls on mountains. Water flows down again. It makes the same journey, over and over.