Drainage Basins

Question 1

What are drainage basins?

Answer 1

Natural systems viewed as open local hydrological cycles

Question 2

What is a rivers drainage basin?

Answer 2

The area surrounding the river where the rain falling on the land flows into the river?

Question 3

What else can a rivers drainage basin be called?

Answer 3

Catchment area

Question 4

What is the boundary of the drainage basin?

Answer 4

Watershed - Any precipitation falling beyond the watershed enters a different basin

Question 5

What enters and leaves the system?

Answer 5

Water enters as precipitation and leaves via transpiration, evaporation and river discharge

Question 6

What is an input of the system?

Answer 6

Precipitation

Question 7

How is precipitation an input?

Answer 7

Includes all the ways moisture comes out of the atmosphere. It is mainly rain however can be snow, hail, dew and frost

Question 8

What are the 6 types of stores?

Answer 8

• Interception
• Vegetation Storage
• Surface Storage
• Soil Storage
• Groundwater Storage
• Channel Storage

Question 9

Explain Interception

Answer 9

When some precipitation lands on vegetation or other structures, like buildings, concrete or tarmac. It creates a significant store of water in wooded areas. Interception storage is only temporary because the collected water may evaporate quickly or fall from the leaves as through fall

Question 10

Explain vegetation storage

Answer 10

Water that’s been taken up by plants. It’s all the water contained in plants at any 1 time

Question 11

Explain surface storage

Answer 11

Includes water in puddles (depression storage), ponds and lakes

Question 12

Explain soil storage

Answer 12

Includes moisture in the soil

Question 13

Explain Groundwater storage

Answer 13

Water stored in the ground, in rocks or soil. The water table is top surface of the zone saturation. porous rocks that hold water are called aquifers

Question 14

What is the zone of saturation

Answer 14

The zone of soil or rock where all the pores are full of water

Question 15

What are porous rocks

Answer 15

Rocks with big holes in them

Question 16

What is channel storage

Answer 16

Water held in a river or stream channel

Question 17

What are the 10 types of flows?

Answer 17

Infiltration, Overland flow / runoff, Through fall, Stem flow, Through flow, Percolation, Groundwater flow, Base flow, Interflow and Channel flow / River discharge

Question 18

Explain Infiltration

Answer 18

Water soaks into the soil. Infiltration rates are influenced by soil type, soil structure and how much water is already in the soil

Question 19

Explain Overland flow / runoff

Answer 19

Water flowing over the land. It can flow over the whole surface or in little channels. It happens because rain is falling on the ground faster than infiltration can occur

Question 20

Explain Through fall

Answer 20

Water dripping from 1 leaf to another

Question 21

Explain Stemflow

Answer 21

Water running down a plant stem or tree trunk

Question 22

Explain Throughflow

Answer 22

Water moving slowly downhill through the soil. Throughflow is faster through pipes - Things like cracks in the soil or animal burrows

Question 23

Explain Percolation

Answer 23

The water seeping down through soil into the water table

Question 24

Explain Groundwater Flow

Answer 24

The water flowing slowly below the water table through permeable rock. Water flows slowly through most rocks, but rocks that are highly permeable with lots of joints have faster groundwater flows

Question 25

Explain Baseflow

Answer 25

Groundwater flow that feeds into rivers through riverbanks and river beds

Question 26

Explain Interflow

Answer 26

Water flowing downhill through permeable rock above the water table

Question 27

Explain Channel flow / River Discharge

Answer 27

Water flowing in the river or stream itself

Question 28

What are the 4 outputs?

Answer 28

Evaporation, Transpiration, Evapotranspiration and River discharge or flow

Question 29

Explain Evaporation

Answer 29

Water turning into water vapour

Question 30

Explain transpiration

Answer 30

It's evaporation within leaves - plants and trees take up water through their roots and transport it to their leaves where it evaporates into the atmosphere

Question 31

Explain Evapotranspiration

Answer 31

The process of evaporation and transpiration together

Question 32

What is Potential Evapotranspiration (PET)?

Answer 32

It's the amount of water that could be lost by evapotranspiration. Actual evapotranspiration is what actually happens

Question 33

Give an example of PET

Answer 33

A desert PET is high (because heat increases evaporation) but actual transpiration is low (because there isn't much moisture)

Question 34

Explain River Discharge or flow

Answer 34

The discharge of a river is the volume of water which flows through it in a given time. Normally measured in cubic metres per second

Question 35

What does the Water Balance Show?

Answer 35

The balance between inputs and outputs.

Question 36

How is the water balance worked out?

Answer 36

From the inputs (precipitation) and outputs (channel discharge and evapotranspiration). The water balance is how much water is stored in the system

Question 37

How is the water balance shown in the UK?

Answer 37

Shows seasonal patterns

Question 38

What happens in wet seasons?

Answer 38

Precipitation exceeds evapotranspiration creating a water surplus. The ground stores fill with water so there's more surface runoff and higher discharge, So river levels rise

Question 39

What happens in drier seasons

Answer 39

Precipitation is lower than evapotranspiration. Ground stores are depleted as some water is used by plants and humans and some flows into the river channel but isn't replaced by precipitation

Question 40

What happens at the end of the dry season

Answer 40

Theres a deficit of water in the ground. The ground stores are recharged in the next wet season