As Revision Booklet
Subjects: Philosophy, classics, music tech and geography
Notes and Revision for Geography:
Links: https://sites.google.com/a/halliford.net/a-level-geography/home/exam-materials http://coolgeography.co.uk/A-level/AQA/AQA%20A%20level.htm http://web.aqa.org.uk/qual/gce/humanities/geography_materials.php
Topic 1: Rivers and Flood Management.
Drainage Basins:
A drainage basin is an area drained by its rivers and tributaries. It is a natural system with varied inputs of precipitation and varied outputs of water, for example, inputs: rain, snow or ice, outputs: evaporation, transpiration, and evapotranspiration and river flow. When the inputs and the outputs balance out it is called the water balance. The summary of water balance:
Precipitation= evaporation + transpiration + river flow + storage
NOTE: water is stored in porous rocks, soils, peat and vegetation. During heavy rainfall or a monsoon the water or “precipitation” storage is high. However when there is little rain or a drought then the precipitation storage is depleted.
River Discharge:
The river discharge is the volume of water that flows in a river channel (usually per second)
A few examples of FACTORS affecting and influencing river discharge:
Geology: permeable rocks like chalk would store most of the precipitation and then release it slowly. This reduces the discharge. However impermeable rocks have the opposite effects.
Slopes: water tends to move slower through or across gentler slopes than it does on sheer or steeper slopes. If the slope is steep it is usually located upstream, also with steep slopes rapid water movement occurs which causes white water. With gentler slopes that are usually located downstream, water flows gently, hence the name.
Soils: same effects as permeable rocks but once the soil storage becomes too high the water will not be absorbed. Impermeable soils like clay soils do not absorb water at all and in turn increase discharge.
Drainage
Notes and Revision for Geography:
Links: https://sites.google.com/a/halliford.net/a-level-geography/home/exam-materials http://coolgeography.co.uk/A-level/AQA/AQA%20A%20level.htm http://web.aqa.org.uk/qual/gce/humanities/geography_materials.php
Topic 1: Rivers and Flood Management.
Drainage Basins:
A drainage basin is an area drained by its rivers and tributaries. It is a natural system with varied inputs of precipitation and varied outputs of water, for example, inputs: rain, snow or ice, outputs: evaporation, transpiration, and evapotranspiration and river flow. When the inputs and the outputs balance out it is called the water balance. The summary of water balance:
Precipitation= evaporation + transpiration + river flow + storage
NOTE: water is stored in porous rocks, soils, peat and vegetation. During heavy rainfall or a monsoon the water or “precipitation” storage is high. However when there is little rain or a drought then the precipitation storage is depleted.
River Discharge:
The river discharge is the volume of water that flows in a river channel (usually per second)
A few examples of FACTORS affecting and influencing river discharge:
Geology: permeable rocks like chalk would store most of the precipitation and then release it slowly. This reduces the discharge. However impermeable rocks have the opposite effects.
Slopes: water tends to move slower through or across gentler slopes than it does on sheer or steeper slopes. If the slope is steep it is usually located upstream, also with steep slopes rapid water movement occurs which causes white water. With gentler slopes that are usually located downstream, water flows gently, hence the name.
Soils: same effects as permeable rocks but once the soil storage becomes too high the water will not be absorbed. Impermeable soils like clay soils do not absorb water at all and in turn increase discharge.
Drainage