HYDROGRAPHS- Water Flashcards
What is a hydrograph
A graph of river discharge against time
What is a storm hydrograph
Graph of discharge of a river leading up to and following a storm or rainfall event
What does a storm hydrograph predict
How a river might respond to a rainstorm
Why is this good
To help us manage the river
What is the time taken from the peak rainfall to the peak discharge called?
The lag time
Why do drainage basins with steep sides tend to have flashier hydrographs than gently sloped river basins?
Bc water flows more quickly on the steep slopes. This means it will reach the river quicker too.
What does the rock type have to be for overland flow to be higher?
Impermeable
In what two ways is water lost from vegetation?
- Evaporation
- Transpiration
How does deforestation impact a river
. Reduces interception rates
. Exposes the soil to greater rates of erosion
. Leads to sedimentation of the channel
. Leads to a greater chance of flooding
How does afforestation help a river
Opposite effect.
. It is a useful flood prevention measure.
What affects does agriculture have:
. Ploughing breaks up the topsoil
. Allows greater infiltration, subduing hydrographs.
What happens when forests are removed
The new vegetation has fewer leaves and shallower roots.
