The Water Balance Flashcards
What are outputs?
Evaporation is the main output along with transpiration (the loss of water as a vapour from plant and tree leaves = evapotranspiration.
The final output is river discharge (water flowing out of the basin).
What are the 5 stages of a soil moisture graph?
Surplus Use Deficiency Recharge Field capacity
What is soil moisture surplus?
Soil water store is full which gives a surplus of soil moisture for plants and run off into streams.
What is soil moisture use?
Plants rely on stored water which is gradually used up.
What is soil moisture deficiency?
Plants must have adaptations to survive for long periods or land must be irrigated.
What is soil moisture recharge?
The soil water starts to be recharged.
Why is the soil moisture graph useful?
Can determine: droughts and deficiencies occur, flooding, irrigation times, need for a water transfer system, long term capacity changes.
What are inputs?
The most obvious input is rain but snow, hail & dew all act as inputs too. These inputs are grouped under the term precipitation, water that falls or condenses on the ground.
How can water leave the drainage basin?
Evaporation, transpiration, inter-basin transfer, river discharge via channel flow.
How is water stored in the drainage basin?
Interception, surface store, soil moisture store, groundwater store.
What is surface store?
When water is held in the surface of the earth. This may be a puddle, a lake or a garden pond.
What is groundwater store?
When water is held in saturated ground.
How can water be transferred?
- stem flow
- canopy drip
- throughfall
- infiltration
- throughflow
- pipeflow
- percolation
- groundwater flow (base flow)
- capillary action
- channel flow
- surface run off (overland flow)
What is capillary action (or rise)?
Water that may move upwards towards the surface.
What is percolation?
Water that travels from unsaturated into saturated ground.
