Water Budgets

Question 1

What is the water budget?

Answer 1

The difference between water inputs and outputs in any given place

Question 2

What does the water budget explain?

Answer 2

It explains the local availability of water and why this can vary

Question 3

What does the water balance equation model?

Answer 3

It models the drainage basin water budget

Question 4

What factors does the water balance equation consider?

Answer 4

Precipitation input (P) , channel flow (Q), potential evapotranspiration (PE) and storage (S)

Question 5

What is the water balance equation written as?

Answer 5

P = Q + PE +/- S

Question 6

What does the water balance equation explain about the level of channel flow (Q)?

Answer 6

It explains the level of channel flow - its determined by P input and PE output and flows into and out from local stores such as groundwater

Question 7

What does P > PE = ?

Answer 7

A positive water balance - leading to a surplus and potential recharge of S or a flood risk

Question 8

What does P < PE = ?

Answer 8

A negative water balance - leading to a deficit and utilisation of S or drought

Question 9

South Hampshire vs Cairo soil moisture budget graphs?

Answer 9

South Hampshire shows a potential flood risk and potential drought as P and PE change in amount compared to Cairo that has a water deficit as PE is almost always greater than P