5.2c Flashcards
How do humans disrupt the drainage basin cycle
They accelerate the process through
- deforestation, changing land use
- and by creating new water storage reservoirs or abstracting water
- e.g in amazonia, colorado, ogallala aquifer
What is humanity changing in water cycle
1) rivers and drainage
2) the character of the ground surface (its shape, texture and covering)
How do humans interfere with river management
1) Construction of storage reservoirs holds back river flows
2) Abstraction of water for domestic flow and industrial use reduces river flows
3) Abstraction of groundwater for irrigation lowers water tables
How does deforestation affect drainage basins
Clearance of trees reduces evapotranspiration, but increases infiltration and surface runoff
How does making land use agricultural affect the drainage basin
- Arable to pastoral: compaction of soil by livestock increases overland flow
- Pastoral to arable: ploughing increases infiltration by loosening and aerating the soil
How does chnaging land use to urbanisation affect drainage basin
- Urban surfaces (tarmac, tiles, concrete) speed surface runoff by reducing percolation and infiltration
- Drains deliver rainfall more quickly to streams and rivers, increasing chances of flooding
What is most affected by humans
evaporation and evapotranspiration
interception
infiltration
groundwater
surface runoff
What in colorado extracts water
dams on colorado river
Define confined and unconfined aqifer
- confined = water in permeable rock surrounded by impermeable rock
- Unconfined aqifer = permeable rock is surrounded by permeable rock, so can flow out, or be recharged
Describe the ogallala aquifer
check out the input on ogallala aquifer on the prereading slide of 1.5
How has deforestation affect amazon basin
ALMMM
A lowering of humidities
Less precipitation
More surface run off and infiltration
More evaporation, less transpiration
More soil erosion and silt being fed into rivers
