Human Impacts On Drainage Basin

Question 1

Reservoirs/ Dams

Answer 1

Interrupt natural river flows by delaying flow through drainage basin

More evaporation in reservoirs, which increases salinity

May affect ecosystems

E.g. Tana River floodplain, Kenya reduced vegetation and reduced river flow

*Any other dam example (Xiyaburi, Turkey, Libya)

Question 2

Over-abstraction

Answer 2

Too much aquifer abstraction, which reduces groundwater and leads to rivers drying

E.g. Thames Basin, which provides 40% London’s water
-Receives lower rainfall creating further pressure
-However, management has increased N-London grounwater

E.g. Ogallala aquifer

Question 3

Deforestation

Answer 3

Disrupts natural hydro-logical processes

E.g. Amazon becoming less able to recycle water = forest degradation

Also:
-Forests cleared for palm oil etc…
-Water directly hit soil
-Causes soil degradation so less infiltration
-Groundwater depletes so rivers run dry

Question 4

Urbanisation

Answer 4

More impermeable surfaces, less infiltration, more surface runoff

*Link to hydrographs:

Shorter lag = increased flood risk etc…