CWTA - Rivers - What Is A River




Connecticut Water Trails Association

"What makes a river so restful to people is that it doesn't have any doubt - it is sure to get where it is going, and it doesn't want to go anywhere else."

- Hal Boyle

Table Of Contents

Connecticut Water Trails

Basic Concepts

Paddling Resources

Types Of Water Ways

Rivers Main Page

Connecticut Water Trails Program

Rivers

What Is A River ?

Rivers

A river is a natural stream of water which flows in a channel towards a mouth or lake or another river. Rivers have two banks (left and right bank). They have a bed over which the water flows. Rivers always have a source, from where they start. Rivers always flow downhill.

River Banks

Rivers have two banks - the right bank and the left bank. If you stand in a river and face the way the water is flowing, the right bank will be on your right hand side and the left bank will be on you left hand side.

River Bed

The river bed is the bottom of the river. It can be made of stones, pebbles, boulders, rock and mud. The water flows over the river bed. You can see the river bed in streams, and in the upper course of a river, because the water is shallower. In the middle and lower courses of a river, you cannot see the river bed because the water is much deeper.

The river bed can be seen between the boulders and stones. The boulders and stones also form part of the river bed.

River Channel

The river channel is the course for the river water. It can either be a straight channel like a canal, or a meandering channel. The channel gives the river its shape.

Courses Of Rivers

Rivers have three courses. The course is the journey the river makes to reach the sea. Rivers never have a straight course from source to mouth. Their course is always bendy.

The upper course is found in the mountains and hills where the river rises from its source. Often waterfalls and rapids are also found in this course. The river is usually fast flowing in the upper course. There are lots of stones and boulders for the water to flow over. The river starts as a stream in the upper course and flows through V-Shaped valleys.

The middle course is where the river starts to become wider and deeper. The land which the river flows over is becoming flatter. The river starts to meander or bend in the middle course.

The lower course is where the river becomes its widest and deepest. This course is found closest to the sea where the river has its mouth. The flat area of land by the river banks is known as a floodplain. Farmers grow crops there. Sometimes a river can also have an estuary or a delta as its mouth.

Stages Of Rivers

There are also three stages to a river's life.

Stage 1 is a youthful river. This is the river in its upper course where it is fast flowing and is a stream.
Stage 2 is the mature river. This is the river in its middle course where it has meanders and is flowing more slowly. Other rivers join as tributaries in its mature stage.
Stage 3 is the river in old age. This is the river in its lower course, where it flows slowly towards its mouth at the sea.

The River Source

The source is the start, or beginning, of a river. The source of a river is usually found in the hills or mountains. A river can have more than one source. The source is where a river begins its journey.

Types Of Source

There are many different ways in which rivers can begin:

Springs - Some rivers begin where water flows out of rocks. Rainwater sinks through the soil and trickles through the cracks and spaces in rocks such as chalk and limestone. These are called permeable rocks. The water continues to do this until it reaches a rock like clay. Clay is an impermeable rock.

The water gradually builds up between the boundary of impermeable and permeable rocks. Eventually, it trickles out of the rocks.

Rills and streams. - A lot of rain falls on mountains. Rainwater flows down slopes and quickly makes channels. At first the channels are small. They are called rills. These join together to make bigger rills. Finally a stream is formed. The streams join up to make a river.

Lakes - The source of some rivers is a lake.

Melting snow and ice - Water from a melting glacier may be the source of a river. The snow and ice melt when the weather gets warmer. This forms a lake in front of the glacier. The water rushes into channels in the V-Shaped valley and eventually forms a river.

Bogs - In some places, rain water can't sink into the ground as the ground is too wet already. The water forms a bog. The soil and plants nearby soak up the water. The water flows out of the bog to form lakes and streams.

The River Mouth

At its mouth, the river flows into another body of water. The mouth may be where the river meets the sea, a lake or a larger waterway. Most rivers flow out into the sea, and this is where they end their journey.

Not all river mouths are the same. There may be an estuary or delta at the mouth. Not all rivers enter the sea. Some rivers simply dry up.

The 'mouth' is where the river stops flowing.