Water balance and soil moisture balance Flashcards
(18 cards)
What is the equation for water balance? (what does it stand for)
P=Q+E+-S
Where P = precipitation, Q = run-off, E = evapotranspiration, S = changes in storage.
What does a water surplus indicate?
Excess water available, soil fully saturated (additional precipitation will lead to excess water). potential for surface run-off, increasing river discharge and flooding.
What is utilisation in the context of water balance?
The process by which plants use available soil moisture. Plants draw water from the soil to meet their needs.
What is a water deficit?
Less water within the system, evapotranspiration exceeds precipitation, soil water is depleted. Can lead to falling river levels and to water stress.
What is recharge in the water balance?
When soil moisture is replenished by precipitation after a dry period.
- important to ensure soil moisture levels are maintained
Define field capacity.
The maximum amount of water that soil can hold before it becomes saturated.
What is river regime?
-Rivers will always have a regime which they follow – some months the
discharge of the river will be higher than others.
-The water balance
looks at how the amount of precipitation compares with the water
leaving the system as runoff or as evapotranspiration.
-This balance will change throughout the year and will be affected by the overall climate of the area near to the river.
-‘Usual’ conditions: Precipitation will be matched by run-off and evapotranspiration giving a ‘normal’ river level.
What happens during usual conditions in a river regime?
Precipitation is matched by run-off and evapotranspiration, resulting in normal river levels.
What do soil moisture budget diagrams show?
The amount of water in the soil at different times.
How can soil moisture diagrams help predict floods?
By indicating when the soil is full, checking saturation, estimating run-off, and showing seasonal changes.
Fill in the blank: The process that leads to falling river levels and water stress is called a ______.
water deficit.
True or False: During rainy seasons, the soil gets saturated faster, raising flood risk.
True.
What is the significance of knowing when the soil is full?
It helps predict potential flooding as extra rain cannot be absorbed.
How does soil moisture affect run-off during rainfall?
If the soil is wet, more water will run off, increasing flood risk.
What role does monitoring utilisation play in water management?
It helps in understanding plant water requirements and managing irrigation schedules.
What is the impact of dry seasons on soil moisture?
The soil can absorb more water, lowering flood risk.
What is the water balance equation used for ?
used by hydrologists to plan for future water supply and flood control
Why is monitoring utilisation useful
helps understand plant water requirements and managing irrigation schedules
