The hydrological cycle
- Created by: GeorgeGreen12
- Created on: 17-04-17 10:33
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- the hydrological cycle
- 1) rain water fall onto the ground and flows on the surface to rivers and lakes (known as run-off)
- 2)rainwater soaks into the soil (infiltration) and flows slowly through to the rivers (known as through flow)
- 3)rainwater soaks into the rocks below the soil. it moves slowly through the air spaces(pores) or flows along cracks and joints (known as groundwater flow)
- processes
- evaporation- as water heats up, it returns to the atmosphere as water vapour
- condensation- water vapour forms into tiny water droplets as the air carrying it cools, sometimes forming visible clouds
- precipitation-the tiny water droplets collide and grow until they fall to the ground as either rain or snow
- threats to the hydrological cycle
- river pollution- untreated sewage pumped into the rivers can lead to serious diseases
- fertilisers and pesticides from intensive agriculture can poison wildlife and affect water quality(eutrophication)
- chemicals from factories can poison wildlife and affect water quality
- plastic bags and waste can kill wildlife, block water pipes and affect the quality
- large scale water management- the 3 gorges dam, china. see the revision book, page 23.
- small scale water management- wells can help reach underground water, hand pumps means there is less chance of contamination. water harvesting.
- the effect of climate change on the hydrological cycle
- there may be distinct wet and dry season- for example the Sahel in Africa has a short wet season so there is little water stored
- weather cycles may occur (3-5 dry years followed by the same amount of wet years) this can lead to food shortages
- rising temperatures mean that dry places like the sahel get dryer and wet places like the UK get wetter
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