Modifications to Catchment Stores + Flows, + to Channel Flows Flashcards
1
Q
How can catchment flows + stores, + channel flows be modified?
A
by:
- land-use changes
- abstraction
- water storage
2
Q
What are the 3 types of land-use changes?
A
- deforestation
- afforestation
- urbanisation
3
Q
What is deforestation?
A
- removal of veg. esp. trees
4
Q
What is afforestation?
A
- planting of trees in areas w/o trees
5
Q
What is urbanisation?
A
- inc. in proportion of ppl living in areas classified as urban
6
Q
How does deforestation affect the drainage basin?
A
- dec. EVT
- dec. infiltration rates: removes natural gaps so less permeable
- dec. interception
- inc. channel flow: more surface runoff
7
Q
How does afforestation affect the drainage basin?
A
- inc. EVT
- inc. infiltration rates
- inc interception
- dec. channel flow: causes lower river lvls
8
Q
How does urbanisation cause larger flows into river channels?
A
- roads + buildings have impermeable surfaces + likely to have drains: dec. infiltration rates + inc. overland flow
- deforestation dec. transpiration: more water in catchment area
9
Q
What is water abstraction?
A
- removal of water from a body of water (river, lake, reservoir or groundwater store)
10
Q
Why is water abstracted?
A
- to meet water demands for drinking water, sanitation etc.
11
Q
How can unsustainable water abstraction cause changes in a river + its catchment area?
A
- water lvls can dec. on the surface + groundwater lvls, affecting channel flow + discharge + may cause more deposition
- water table may fall if groundwater overexploited: may cause water lvls above ground to dec.
12
Q
How can water be stored above ground?
A
- by dams + reservoirs
13
Q
How do dams + reservoirs affect the catchment area + flows?
A
- dams: directly stop + control channel flow as provides a barrier
- reservoirs:
- can raise water table underground, but may lower water table in other areas
- v. large so lots of water may enter atmo. by evaporation, inc. cloud formation in area: affects pptn
