ENV234H1 Lecture 16: Water Budget
16 Nov 2016
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Document Summary
97. 5% of all water is salt water. Only 2. 5% of total globe is freshwater. Of this freshwater, 0. 3% lakes and river storage: only this is renewable, 0. 0075% of total global water. Is there enough freshwater: global runoff on land: total of 40,000 cubic km/year, remote flow: 19, uncanptured floodwater: 50, accessible runoff: 31, used by humans: 17% of total using more than half of what is easily accessible. Large aquifers (pools of ground water) are in wet regions. Large aquifers in deserts (e. g. , sahara: sahara used to be green thousands of years ago, before the desert covered it up. More water used than water replenished: saharan basin: 130% recharge rate used, saudi arabia: 480% recharge rate used, gaza: 160% recharge rate used, ogallala (usa): 320% - fruits and vegetables are grown in the desert. In canada, 85% of rural population rely on groundwater. Either economic scarcity or physical scarcity: water not easily accessible.
