Water Balance

Question 1

what is water balance

Answer 1

is the balance between inputs (precipitation) and outputs (run off, evapotranspiration, soil and ground water storage)

Question 2

what is the formula for water balance

Answer 2

Precipitation= discharge + evapotranspiration +/- changes in storage

Question 3

explain positive and negative water balance

Answer 3

if precipitation EXCEEDS run-off and evapotranspiration it is a POSITIVE WB (amount of water is increasing)– particularly in september
if the opposite is true then it is a negative wb– particularly in summer as it is warmer

Question 4

what is total runoff

Answer 4

is a measure of the proportion of the total precipitation that makes its way into streams and rivers

Question 5

what causes variations in run off (factors)

Answer 5

differences in: soil water, rock type, precipitation intensity and vegetation cover
time of year- affects rates of evapotranspiration and vegetation growth (interception)

Question 6

River Wye (wales)

Answer 6

upper river basin made up of impermeable stones so groundwater flow is limited and soils become saturated much quicker.
run off highest in winter- most rainfall and least amount of vegetation cover