Home » River Processes » The Vol. of Water in a River

River Processes	River Valley Development	River Fieldwork	Overflowing Rivers	Rivers Need Care	Rivers & Transport	River Facts
The Water Cycle \| From Source To Sea \| The Vol. Of Water In A River \| The Speed Of A River \| Processes At Work \| Dizzy & The Water Wheel (Glossary)

The Volume of water in a River

Water reaches the river by several routes.

Diagram of the various routes water takes to reach a river.

The amount of water that enters a stream or river is influenced by four conditions.

Presence of Vegetation
Permeability of Rocks
Size of Drainage Basin
Climate

1.The presence of vegetation affects the rate at which water is absorbed by leaves and plants before it is able to soak into the ground. If an area is covered with vegetation, the vegetation will prevent the rain soaking into the ground. There will be less water as surface runoff into the river and so the volume of water into the river will be lowered. However, in an area with little vegetation, there will be nothing to prevent the water entering the ground. The result will be greater surface runoff and so the volume of the water is higher.

2.The amount of water that rocks can absorb is known as its permeability. The permeability of rocks is determined by the size of the pores between the rock particles. If the rock has small pores, water cannot easily pass into the rock and this means that the rock is impermeable. However, if the rock has large pores, water can easily pass through and thus the rock is permeable.

This rock has small pores so water cannot pass easily into the rock i.e. it is impermeable.

This rock has larger pores, so water can easily pass through i.e. the rock is permeable.

3.A river drainage basin is the total area of land drained by a river and its tributaries. Click on the link to see an example of a drainage basin Link to StreamOrder The larger the drainage basin the greater volume of water. This is because there is a greater amount of tributaries resulting in a higher surface runoff.

4.The weather and time of year will influence the amount of water. The amount of rainfall and temperature affects the volume of river. In the drier months, a river channel may be almost empty therefore the volume is low. During the wetter months, the volume will be high and water may overflow the channel and flood the surrounding land. When the temperature is high, there is more evaporation a which reduces the amount of water in the river.

Dizzy the water droplet.

TASK: The vegetation and climate factors may be modelled by using the Water Model Activity

link to hydrograph link to water model activity: (Flash) (Non-Flash)