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Uploaded on Wednesday 22 Feb 2012
Nigeria and the freshwater challenge
Hugo Ahlenius, UNEP/GRID-Arendal
Out of the total precipitation reaching Nigeria, it can be separated into green and blue water. Green water (79% of the precipitation) represents the fraction of rainfall that generates soil moisture and which supports terrestrial ecosystems. It is not returned to groundwater and rivers, but will eventually evaporate or transpire through plants. Blue water, on the other hand, represents the fraction (21%) of the precipitation that runs into rivers and aquifers, and that has a potential for withdrawal for societal use. Out of this, the environmental water flow is the amount of water needed to sustain ecosystem services. In the case of Nigeria, there is a huge potential to increase the withdrawal for irrigation and food production to meet current and future needs.