Water world: Flood Hydrographs Flashcards
What is discharge
Amount of water in a river at any given point or time. Measured in cumecs( cumec metres per second)
When it rains it will either be:
Held in storage
Lost through transpiration
Make its way into rivers either on the surface or underground
What do hydrographs show
River discharge over a given period of time and show the response of a drainage basin and its river to a period of rainfall
What is rising limb
The rising flood water in a river
What is peak discharge
Maximum discharge in a river
What is falling limb
Falling flood water in a river
What is lag time
The time difference between peak rainfall and peak discharge
What is base flow
Normal discharge of the river
What can Storm hydrographs help do
Show How a river will react to heavy rainfall
Predict floods
Plan for future flood events
What does a steep rising limb show
It shows that the surface run-off is high, which may add to flood risks
What does a short lag time mean
It means that the river levels will rise quickly, adding to the risk of flooding
What does a gently sloping falling limb suggest
Is suggests that the river takes quite a long time to get back to its normal flow pattern
