Addressing water stress in Africa through green and blue water management indicators

Water availability and stress may be one of the largest global issues we face in the coming century. Previous global, regional and local assessments of water availability were only limited to blue or terrestrial water sources yet recent research indicates that such assessments should incorporate green, or atmospheric water fluxes that include water in plants and soil. While many general hydrologic assessments of Africa are available this is the first quantitative assessment of water stress that incorporates both blue and green water availability. This thesis documents how the newly emerging concepts of hydroclimatic regimes and the landscape water availability depict a much richer picture of water availability in Africa than traditional hydroclimatic indicators such as the runoff ratio or the aridity ratio. Over the African continent, atmospheric water fluxes are shown to be the principal hydrologic force. Interestingly, nearly all regions with high levels of water stress are areas where green water flows are dominant. The Green Water Management Potential (GWMP) indicator is introduced to document that green water management activities are essential to alleviating the highest water stress levels.