EQ1: Water Budget/River Regime

Question 1

What is a water budget

Answer 1

Shows the annual balance between inputs and outputs and their impact on soil water availability

Question 2

What is soil moisture recharge

Answer 2

The replenishment of stores of water used during warmer months when evapotranspiration exceeds precipitation

Question 3

What is soil moisture surplus

Answer 3

• when soil is saturated and water cannot enter, it flows over the surface

When precipitation exceeds evapotranspiration

Question 4

What is soil moisture utilisation

Answer 4

When potential evapotranspiration is greater than precipitation - water storage is used up by plants or lost via evaporation

Question 5

What is soil moisture deficit

Answer 5

There is a deficiency of soil water as the soil store is used up

Question 6

What is potential evapotranspiration

Answer 6

An estimate of the water lost through evaporation and transpiration in any given period

Question 7

What is the discharge of a river

Answer 7

The volume of water which flows through a river at a given times

Question 8

What is a river regime

Answer 8

The annual variation of discharge at a particular point, measured in cummecs

Question 9

What are the factors affecting river regimes

Answer 9

• climate
• evapotranspiration
• location - for example being in a rain shadow
• precipitation
• human activity - deforestation

Question 10

What are the two types of river regimes

Answer 10

1 - simple regimes = when a river experienced a period of seasonally high levels of discharge followed by low discharge

2 - complex regimes = where larger rivers cross several different climate zones therefore experiencing the effects of different seasonal climate vents

Question 11

Define lag time

Answer 11

The time taken between peak precipitation and peak discharge

Question 12

Define rising limb

Answer 12

Shows how long it takes for a river to peak following a precipitation event

Question 13

Define falling limb

Answer 13

When discharge decreases and the river levels fall

Question 14

what are three physical factors affecting hydrographs

Answer 14

1 - size = larger catchments typically have higher flows, but it takes longer for peak flow to occur

2 = shape = circular catchments concentrate water more wuickly, in long narrow catchments it takes time to reach a point downstream

3 = urbanisation = concreted areas, roads and buildings have low permeability and increase over land flow, thus reducing lag times and increasing peak flows