Tuesday, March 31, 2009
WATER BALANCE
The first thing which is also the only thing, we learnt today, is WATER BALANCE. A water balance can be used to help manage water supply and predict where there may be water shortages. It is also used in irrigation, flood control and pollution control. All we need to remember is just an equation: P= Q + E + △S (Input= Output). P is precipitation. Q is total streamflow (runoff). E is evapotranspiration. △S is the change in storage (in soil and bed rock).
When △S = 0, what will happen?
-The soil cannot absorb water any more
- This kind of soil cannot attract more water.
- Using the wrong kind of soil.
All in all, there is no soil storage.
Here are several cases that can influence water balance.
That’s all for today’s lesson. Although it is very short, it is quite important for us to have a better understanding on water cycle.
Done by Tianyu