Water Balance

1. Task Sheet: Water Balance
1. Make a copy of the water balance equation.
2. Define the terms precipitation and evapotranspiration.
3. Explain how these two terms are used to work out the water balance?
4. Define the following terms; soil moisture recharge, soil moisture surplus, soil moisture
utilisation and soil moisture deficit. This could be achieved by annotating a diagram such as the
one below.
5. Explain why each of the terms you have defined occurs.
6. Describe the annual pattern of the water balance for the water balance graph of an area of
the UK shown above.
7. Explain why the water balance is important if you want to understand how river runoff changes
of the year.
8. Use the two water balance graphs on the next page. Describe and explain the water balance
for the both the Atacama Desert in Peru and Boliva, South America.

4. Notes for Water Balance
Equation of the water balance
Define and explain soil moisture recharge, soil moisture surplus, soil moisture utilisation and soil
moisture deficit
Why do they occur?