Factors affecting changes in the water cycle Flashcards
Name 3 human activities affecting changes in the water cycle.
land-use change
farming practices
water abstraction
What land use changes affect the water cycle the most?
urbanisation and deforestation
How does urbanisation affect the water cycle?
it replaces vegetated ground with impermeable concrete and tarmac so water cannot infiltrate the soil, which increases overland flow and makes flooding more likely
How does deforestation affect the water cycle?
the removal of the trees leads to surface run off and soil erosion which reduces the soils water store
How does farming practices affect the water cycle?
soils covered with plants have higher infiltration and soil water rates and, therefore reduced soil runoff
Define water abstraction.
the extraction of water from rivers or groundwater aquifers
How does water abstraction affect the water cycle?
Aquifers can become depleted and they can be contaminated by inflowing saltwater if the water table drops below sea level, eg. the chalk aquifer beneath London
What is the impact of irrigation in the Middle East?
irrigation causes water to be abstracted from underground aquifers which were formed thousands of years ago and are in serious danger of becoming depleted
What are peatlands?
thick deposits of partly decomposed vegetation
How does the drainage of peatlands affect the water cycle?
it lowers the water table which causes the peat to become dry and therefore vulnerable to erosion
How much carbon do English peatlands hold?
584 million tonnes
Why are the impacts of California (LA) droughts on the water cycle?
- absence of water from agriculture and city residents
- replacing plants with desert plants
- agriculture uses 80% of its water
What is the impacts of changing ocean currents?
- moves heat and carbon around the planet
- impacts the ecosystems in the region, but also weather and climate patterns
