How do humans affect the water and carbon cycle Flashcards
Urbanisation:
-conversion of land use from rural to urban
-farmland and woodland are replaced by houses and roads
-artificial surfaces are impermeable so little/no infiltration so rise in water levels
-drainage systems results in high proportion of water to flow quick into streams and rivers
Farming:
-clearance of forest reduces carbon storage
-soil carbon storage is also reduced by ploughing and soil exposure to oxidation
-lack of biodiversity in farmed systems
-ploughing increases evaporation and accelerates run off because of heavy machinery compacting soil
Forestry:
-higher rates of rainfall interception
-increased evaporation as rainfall is on leaf surfaces
-increase transpiration
-increase carbon stores
-reduce run off and stream discharge as high interception and evaporation rates
Water extraction
-river kennet:
-drains an area of 1200km2 in Wiltshire
-upper catchment comprises of chalk which is highly permable
-reduced flows in the river by 10-14%
Aquifers and artesian basin
-aquifers= permeable or porous water bearing rocks such as chalk
-rising temps increase evapotranspiration losses, recharge resumes in the late autumn
-artesian aquifer= when groundwater is trapped by a well or borehole, water will flow to the surface under its own pressure
What does ploughing do?
Increases oxygen getting into soil, so more decomposition occurs, realising CO2