Physical Geography Revision
,Contents
Water Cycle and Insecurity
Carbon Cycle and Energy Security
Tectonic Processes and Hazards
Coastal Landscapes and Change
, Water Cycle and Insecurity
EQ1
Distribution of global water
• Hydrosphere- water on earth's surface, makes up 96.5%
• Atmosphere- the air above us, makes up 0.001%
• Cryosphere- frozen water, makes up 1.7%
• Lithosphere- rocky outer layer of earth, make up 1.7%
Limited availability of water
• Accessible freshwater only makes up 1%
Inputs, outputs, flows and fluxes
Fluxes- types of movement of water, mainly rainfall, surface run off, evapotranspiration
• The main input is precipitation
• The main outputs are evaporation, transpiration and discharge
Relief Rainfall- occurs due to landscape shape
Convectional rainfall- happens due to warmth in the air rising
Frontal rainfall- warm air meets cooler air front, warm air rises mixing to form rainfall
Flows-
• Interception- through retention of water by plants or soil
• Infiltration- water soaks into plants and soil
• Percolation- deep transfer of water into bedrock
• Throughflow- lateral transfer of water downslope
• Groundwater flow- very slow transfer of percolated water
• Surface runoff- water movement overland
• Chanel flow- waters enters river or stream
Drainage basins- physical factors
Climate-
• Mainly impacts inputs and outputs
• Changes the amount and type of precipitation and amount of evaporation
Soils-
• Affects the importance of different flows in the system
• Determines infiltration rates
Geology-
, • Affects surface run off
• Impacts percolation and groundwater flow
• Effects soil formation
Relief-
• Effects surface run-off
• Impacts the amount of rainfall
• Slopes affect run off
Vegetation-
• Affect surface run-off
• Presence of plants has major impact on interception, infiltration and transpiration.
Human factors on drainage basins
River management-
• Construction of reservoirs
• Use of domestic supply
• Irrigation
Deforestation-
• Reduces evapotranspiration
• Increase infiltration
• Increases surface run off
Agriculture-
• Arable to pastoral farming (soil compacts)
• Ploughing increase infiltration for arable farming
Urbanisation-
• Tarmac, concrete etc, speed up surface run off increasing flooding
Case study- Amazon basin
Deforestation has disputed the drainage basin cycle in a number of ways-
• A lowering in humidities
• Less precipitation
• More surface sun off and infiltration
• More evaporation, less transpiration
• More soil erosion and silt being fed into rivers
Hydrographs
Flashy hydrograph-
,Contents
Water Cycle and Insecurity
Carbon Cycle and Energy Security
Tectonic Processes and Hazards
Coastal Landscapes and Change
, Water Cycle and Insecurity
EQ1
Distribution of global water
• Hydrosphere- water on earth's surface, makes up 96.5%
• Atmosphere- the air above us, makes up 0.001%
• Cryosphere- frozen water, makes up 1.7%
• Lithosphere- rocky outer layer of earth, make up 1.7%
Limited availability of water
• Accessible freshwater only makes up 1%
Inputs, outputs, flows and fluxes
Fluxes- types of movement of water, mainly rainfall, surface run off, evapotranspiration
• The main input is precipitation
• The main outputs are evaporation, transpiration and discharge
Relief Rainfall- occurs due to landscape shape
Convectional rainfall- happens due to warmth in the air rising
Frontal rainfall- warm air meets cooler air front, warm air rises mixing to form rainfall
Flows-
• Interception- through retention of water by plants or soil
• Infiltration- water soaks into plants and soil
• Percolation- deep transfer of water into bedrock
• Throughflow- lateral transfer of water downslope
• Groundwater flow- very slow transfer of percolated water
• Surface runoff- water movement overland
• Chanel flow- waters enters river or stream
Drainage basins- physical factors
Climate-
• Mainly impacts inputs and outputs
• Changes the amount and type of precipitation and amount of evaporation
Soils-
• Affects the importance of different flows in the system
• Determines infiltration rates
Geology-
, • Affects surface run off
• Impacts percolation and groundwater flow
• Effects soil formation
Relief-
• Effects surface run-off
• Impacts the amount of rainfall
• Slopes affect run off
Vegetation-
• Affect surface run-off
• Presence of plants has major impact on interception, infiltration and transpiration.
Human factors on drainage basins
River management-
• Construction of reservoirs
• Use of domestic supply
• Irrigation
Deforestation-
• Reduces evapotranspiration
• Increase infiltration
• Increases surface run off
Agriculture-
• Arable to pastoral farming (soil compacts)
• Ploughing increase infiltration for arable farming
Urbanisation-
• Tarmac, concrete etc, speed up surface run off increasing flooding
Case study- Amazon basin
Deforestation has disputed the drainage basin cycle in a number of ways-
• A lowering in humidities
• Less precipitation
• More surface sun off and infiltration
• More evaporation, less transpiration
• More soil erosion and silt being fed into rivers
Hydrographs
Flashy hydrograph-
