EESA10H3 Lecture Notes - Lecture 3: Giardia Lamblia, Typhoid Fever, Surface Runoff
9 Aug 2012
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Document Summary
The earth is composed of 71% water mostly saltwater. Moderates climate, dilutes and removes pollutants and wastes. Every living creature needs water human body is 60% water. Withdrawal the amount of water removed from a river, lake, or aquifer. Some may be returned to the source for reuse. Fresh water = 2. 6% of all water available: mostly in glaciers, ice caps, and groundwater, readily accessible freshwater can be found in lakes, rivers, soil moisture. Stress on the world"s river basins: water stress = <1700 cubic meters/year/person, water scarcity = <1000 cubic meters/year/person. Some areas have lots of water some are too far from population and agriculture not distributed to key areas properly. Precipitation cannot be collected and stored effectively. As a result, lakes and rivers shrink eg. aral sea. How do we use water: 85% is used for irrigation and not returned to the water basin, canada = mainly used to cool power plants.
