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Hydrological Cycle, - - Coggle Diagram
Hydrological Cycle
Drainage basins
- An area of land that is drained by a river
- Water is absorbed by the land through percolation and is transferred to the river by infiltrating the land reaching the water table where through-flow happens
- Through-flow is the lateral unsaturated flow of water
- Water can also be transferred to the river channel via the ground water flow
Factors affecting basins
- Climate, affects the vegetation type and amount of precipitation
- Soil type, determines the amount of infiltration and through-flow and type of vegetation
- Geology, Impacts infiltration, through-flow as different rock types have varying levels of permeability
- Relief, Impacts the amount of precipitation as slopes and gradients impacts the amount of runoff
- Vegetation, the presence of vegetation can impact the rate of interception, infiltration and overland flow as more vegetation will absorb more water
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Drought
- An extended period season or year of deficient rainfall relative to the statistical average
- Defined as a deficit in the hydro-logical cycle
Causes of drought
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- Agricutural overstress of water
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- Over stress of water supplies
Physical drought
- Agricultural, when there is insufficient soil moisture to meet the demands of a specific crop
- Meteorological, when long term precipitation is much lower than normal for an extended period of time
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Storm hydrographs
- A graph that shows a rivers response to a storm event
- Urban hydro-graphs will typically have a short lag time as water is not absorbed by concrete
- Lag time is the time difference between peak rainfall and peak discharge
- Rural areas will typically have a longer lag time as there is more vegetation and permeable ground for water to be absorbed by meaning that less reaches the river as surface run off resulting in a much lower peak discharge level
- The shape of a storm hydro-graph can change depending on human and physical factors such as infrastructure and amount of rainfall or duration of the storm event
Water stores
- Cryosphere, water stored within ice
- Atmospheric, water stored in the clouds as a result of evapouration
- Oceanic, water stored in the ocean
- Groundwater, water stored in underground aquifers
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Flooding
- A surplus in the hydro-logical cycle
- Groundwater flooding occurs after the ground has been saturated by prolonged rainfall
- Flash flooding occurs when a flood happens with a very short lag time
- Meteorological causes of flooding, intense precipitation caused by mid-latitude depressions
ITCZ
- Intertropical convergence zone
- A belt of low pressure around the equator that moves North and South of the equator seasonally
- Causes wet and dry systems in some regions
- Extended dry periods caused by ITCZs can cause drought
Fluxes
- Fluxes are the movement of water from one store to another
- Fluxes happen as a result of evaporation, transpiration, condensation, percolation and surface flow
Hydro-cycle
- Movement of water between stores through a number of processes such as evaporation, transpiration and percolation
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