How does deforestation impact the hydrological cycle?
- Increases surface run-off
- Decreases evapotranspiration
- More floods
- Less water intercepted and stored by the trees
How does urbanisation impact the hydrological cycle?
Removal and replacement of vegetation with impermeable surfaces and drains speeds up overland flow and evaporation which can lead to higher river levels.
How does mining impact the hydrological cycle?
Increased silting up of lakes, rivers and reservoirs leading to a reduced storage capacity in these areas.
How does irrigation impact the hydrological cycle?
- Reduces rivers and underground stores
- Reduces river flow and lowers water tables
- Increases evaporation by placing water in surface stores
- Increases transpiration because new crops removing water from the cycle as they grow.
What is a hydrograph?
Record of river discharge over a period of time
What is the rising limb?
The rising flood water in the river
What is the recession limb?
Falling flood water in the river
What is the basin lag time?
The time difference between the peak of the rainstorm and the peak flow of the river.
What is the base flow?
Normal discharge of the river
What is overland flow?
Volume of water reaching the river from surface run off
What is through flow?
Volume of water reaching the river through the soil and underlying rock layers
Name 5 factors that can influence storm hydrographs
- Area
- Land use
- Types of rock
- Soil type
- Drainage density
- Extent of rainfall
- Previous weather
- Temp
- Tidal conditions
