The water balance Flashcards
What is the water balance equation?
P = O + E +/- S
What is the soil water budget graph?
They show the water balance of a particular location. They also show the relationship between temperature, precipitation and evaporation rates over the year.
Define dynamic equilibrium
The system is in a state of balance.
How is runoff measured?
It is written as a percentage of precipitation.
Why might runoff vary?
Heavily forested river basins
Intensity of rainfall
What does positive water balance mean?
Precipitation exceeds evapotranspiration
What does negative water balance?
Evapotranspiration exceeds evapotranspiration
What is surplus?
When all space in the soil has been filled
What happens during the early months of the year?
Soil moisture recharge (replenished)- precipitation is greater than evapotranspiration
What happens during the early summer months of the year?
Soil moisture utilisation - evapotranspiration exceeds precipitation
What happens towards the end of the summer months?
The soil moisture has all been utilised and it goes into a potential soil moisture deficit
How is discharge measured?
Cross-sectional area x velocity
What is discharge?
The volume of water passing a measuring point in a given time
What is a river regime?
Used to measure the variability in discharge over a given year