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Factors affecting the drainage basin - Coggle Diagram
Factors affecting the drainage basin
Afforestation
An increase in vegetation will increase:
Interception
Transpiration
Evotranspiration
Increasing vegetation will reduce infiltration
Consequently reduce sub-surface processes & surface run-off
Building reservoirs (and dams)
Controls the channel flow in the upper course
Means the rest of the river discharge is controlled
Impacts rates of evaporation
Means rates of condensation are effected
Climate
Refers to the average weather experienced over a 30 year period
Influences amounts of precipitation & rates of evaporation
Influences the vegetation & soil type
Affects rates of:
Evotranspiration
Transpiration
Infiltration
Surface run-off
Deforestation
Decreases the rate of interception
Therefore decreases rates of transpiration & evotranspiration
Increases surface run-off & infiltration
Only if soil is capable
Forest to farming
Land conversion alters:
Interception
Transpiration
Evotranspiration
Does depend on the replacement vegetation
Direction of ploughing may alter surface run-off rates
Affects river discharge rates
Geology
Impacts on sub-surface processes
Percolation
Groundwater flow
More permeable rocks or rocks with weaker lithology will allow water to travel faster
Indirectly impacts soil formation
Vegetation
The precense of vegeation has an impact on the amount of interception, transpiration & infiltration
Different leaf types will affect the type of interception present
Coniferous pines
Deciduous leaves
The loss of vegetation can lead to soil erosion & leaching
Also impacts surface run-off
Irrigation systems
The movement of water by humans will impact channel flow
Infiltration rates may change in an area
Previously dry land may receive water
Sub-surface processes may increase
Over abstraction
Water deficits will be created
Negative impacts on stores such as lakes, rivers & groundwater
Surface run-off rates will change
Any water that falls will be stored & used
Especially in an area with water insecurity
Soils
Determine the amount of infiltration, throughflow & indirectly the type of vegetation
Clay-based soils are thicker & so reduce the amount of water that can infiltrate compared to sandier soils
Urbanisation
Leads to an increase of impermeable surface
Decreases infiltration & percolation rates
Increases surface run-off
Depending on infrastructure quality, channel flow will be affected
Relief
Altitude can impact on precipitation totals & type of precipitation experienced
Areas in the rain shadow will see longer lag times
The gradient of slopes can affect the amount of surface run-off
Affects the lag time within a drainage basin