changes in the water cycle over time Flashcards
how does summer affect the water cycle?
- leaves = evapotranspiration
- storms more common
- total rainfall less
- dry soils = more infiltration
- baked hard soils = more surface run off
- low flow conditions in rivers
how does winter affect the water cycle?
- no leaves = no transpiration
- decrease in evaporation
- high precipitation = saturated ground = less infiltration
- water locked up in snow
- high flow conditions in rivers
what can be a result of extreme weather?
flooding, vegetation destroyed, ecosystems destroyed
what is El Nino?
change in ocean temperatures which means extreme climate variability in different parts of the world
what can be a result of el nino?
drought = fewer plants = less evapotranspiration = less precipitation = drought
what is an example of a human impact on the water cycle?
deforestation, farming practices, water abstraction
what happens after deforestation?
the new vegetation has fewer leaves and shallower roots TMT the new forest uses less water than the previous forest TMT less water returns to the atmosphere
what happens as a result of farming practices?
deforestation for crops (reduces interception and evap.trans.), soil erosion from machinery/cattle (reduces infiltration), irrigation, extraction of groundwater, soil drainage speeds up throughflow (dryer soils)
what % of india and the usa rely on aquifers?
60%
what are the impacts of water abstraction?
- human activities lead to over exploitation
- water gets polluted by industries and agriculture
- cities forced to buy farmland in order to use groundwater
- salt water intrusion - salinization occurs due to rising water table and evaporation of water leaving behind salts
- London, Manchester, Liverpool - water table decreased by 30 metres
- London rising by 2m a year threat to basements, tunnels, foundations and underground
