Drainage Basins

Question 1

What is The Drainage Basin?

Answer 1

The area surrounding the river where the rain falling on the land flows into that river.
Boundary of the drainage basin is known as the water shed.
Drainage basins are open systems.
Water comes into the system as precipitation
Water leaves by evaporation, transpiration and river discharge.

Question 2

Inputs of the drainage basin?

Answer 2

Precipitation

Mainly rain, can be by snow, hail, dew and frost.

Question 3

Storage of water stored in the drainage basin?

Answer 3

1) Interception; by leaves, buildings, concrete or tarmac. Creates significant store of water. Temporary store.
2) Vegetation; water taken up by plants and contained.
3) Surface; water in puddles, ponds and lakes
4) Soil; moisture in the soil
5) Groundwater; stored in soil or in rocks.
6) Channel; held in river or stream

Question 4

Flows of water in the drainage basin?

Answer 4

• Infiltration
• Overland flow
• Throughfall
• Stemflow
• Throughflow
• Percolation
• Groundwater flow
• Baseflow
• Interflow
• Channel flow

Question 5

Outputs in the drainage basin?

Answer 5

1) Evaporation, turn water into water vapour
2) Transpiration
3) Evapotranspiration
4) River discharge

Question 6

What is the water balance?

Answer 6

Affects how much water is stored in the basin. it is worked out from inputs and outputs.

Question 7

How does the water balance work?

Answer 7

Wet seasons - precipitation exceeds evapotranspiration, creates water surplus. Will be more surface runoff and higher discharge so river levels rise.
Drier seasons - precipitation is lower than evapotranspiration. Ground stores are depleted.
By the end of the dry season there will be a deficit, but it is recharged over the next wet season.

Question 8

What is through fall and through flow?

Answer 8

The downward movement of water within the rock under the ground surface.

Water that flows down slope through the soil.