Drainage Basins

Question 1

What is a river’s drainage basin?

Answer 1

Area surrounding river where rainfall on land flows into that river

Question 2

What is the boundary of a drainage basin?

Answer 2

Watershed

Question 3

What type of system are drainage basins?

Answer 3

Open - matter + energy is input + output

Question 4

What are the inputs and outputs of a drainage basin?

Answer 4

Input = precipitation
Output = evapotranspiration, river discharge

Question 5

What are the 6 stores of the drainage basin?

Answer 5

1. Interception
2. Vegetation storage
3. Surface storage
4. Soil storage
5. Groundwater storage
6. Channel storage

Question 6

What is interception?

Answer 6

When precipitation falls on structures e.g. leaves or buildings before reaching soil

Question 7

Where does interception act as a large water storage?

Answer 7

Wooded areas

Question 8

Why is interception storage temporary?

Answer 8

Collected water evaporates or flows as througfall

Question 9

What is vegetation storage?

Answer 9

Water absorbed by plants - includes all water within a plant

Question 10

What is surface storage?

Answer 10

Includes puddles, ponds and lakes

Question 11

What is soil storage?

Answer 11

Moisture in soil

Question 12

What is groundwater storage?

Answer 12

Water stored in ground - as soil moisture or in rocks

Question 13

What is the water table?

Answer 13

Top surface of the zone of saturation - area where all pores in rock and soil are saturated

Question 14

What are aquifers?

Answer 14

Porous rocks that hold water

Question 15

What are 2 stores are part of groundwater storage?

Answer 15

Water table

Aquifers

Question 16

What is channel storage?

Answer 16

Water held in river

Question 17

What are the 10 flows in a drainage basin?

Answer 17

1. Inflitration
2. Overland flow
3. Throughfall
4. Stemflow
5. Throughflow
6. Percolation
7. Groundwater flow
8. Baseflow
9. Interflow
10. Channel flow

Question 18

What is infiltration?

What is infiltration rate affected by?

Answer 18

Water soaking into soil

1. Soil type
2. Soil water content
3. Soil structure

Question 19

What is overland flow? Why does it happen?

Answer 19

Water flowing over land

Occurs bc rainfall onto ground is faster than infiltration rate

Question 20

What is throughfall?

Answer 20

Water dripping from one leaf to another

Question 21

What is stemflow?

Answer 21

Water running down a plant stem

Question 22

What is throughflow?

Answer 22

Water slowly moving downhill through soil.

Question 23

What is percolation?

Answer 23

Water seeping down into water table

Question 24

What is groundwater flow?

Answer 24

Water flowing below water table through permeable rock

Question 25

What is baseflow?

Answer 25

Groundwater flow that feeds into rivers through river banks + beds

Question 26

What is interflow?

Answer 26

Water flowing downhill through permeable rock above water table

Question 27

What is channel flow?

Answer 27

Water flowing into river itself. Also known as river discharge.

Question 28

What are the 4 outputs of the drainage basin?

Answer 28

1. Transpiration 2. Evaporation 3. Evapotranspiration 4. River discharge

Question 29

What is transpiration?

Answer 29

Evaporation from within leaves

Question 30

What is evaporation?

Answer 30

Water turning into water vapour

Question 31

What is evapotranspiration?

Answer 31

Combo of transpiration and evaporation

Question 32

What does the Water Balance show?

Answer 32

Balance between inputs and outputs of drainage system

Question 33

What are the 3 reasons for why the Water Balance varies seasonally in the UK?

Answer 33

1. Precipitation exceeds evapotranspiration in wet season - creates water surplus - ground stores fill with water - more surface runoff + higher discharge - river levels rise 2. Precipitation lower than evapotranspiration in dry season - ground stores depleted - some water absorbed by plants + some water flows into river, but isn't replaced by precipitation 3. End of dry season = water deficit. Ground stores are depleted next wet season.