The definition varies internationally. According to the UN, drought is an extended period (a season, a year or several years) of deficient rainfall relative to the statistical average for a region measured over a very long period of time.
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Card 17
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Occurs when water resources are available but there is insufficient human, institutional and financial capital to access the water in order to meet demand.
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Card 18
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A naturally occurring phenomenon that involves the movement of a mass of very warm water in the equatorial Pacific due to changes in the surface trade winds, atmospheric circulation and ocean currents.
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Card 19
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Excessive richness of nutrients in a lake or other body of water, frequently due to run-off from farming land, which causes a dense growth of plant life and death of animal life from a lack of oxygen.
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Card 20
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The change in state of water from a liquid to a gas.
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Card 21
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The combined effect of evaporation and transpiration.
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Card 22
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The part of a storm hydrograph in which the discharge starts to decrease and return to base flow.
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Card 23
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A humanitarian crisis in which the widespread failure of agricultural systems leads to food shortages and famines with severe social, economic and environmental impacts.
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Card 24
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A flood with an exceptionally short lag time- often minutes or hours.
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Card 25
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Ancient, deep groundwater from former pluvial (wetter) periods.
