The water security ensures adequate access to water on a sustainable basis in sufficient quantity, necessary to sustaining livelihood, socio-economic development, preserving political and peace ecosystem, and providing protection against natural disasters1. Therefore, the concept is not limited to the availability of drinking water but extends to overall human well beings and ecosystem services. Sometimes, there is no issue of water supply but even then the region is water insecure because it is not being judiciously used and evenly distributed. The East African countries are water insecure in both supply and further distribution patterns. It was also concluded that 1/3rd humanity is at risk of water scarcity due to climate.

The phenomenon of climate change is derived by multiple factors and it also affects the multiple fields in human life. However, the intensity of climate change disasters is regional, having slight to extremes consequences. The food security and water security are key fields being affected by the climate change. Among the climatic variables, the water availability is directly suffered from precipitation, however, temperature has partial contribution. It promotes water losses by increasing the rate of evaporation. The future climatic vagaries depend upon local greenhouse gases production, locality of region and adaptive capabilities of the inhabitants. The East African countries are although not a big contributors of climate change due to low industrialization but are most affected countries of the world. The great vulnerability might be the result of the large.

dependence on the natural resources and substantial livelihood. There have been many such incidence in the past in form droughts, floods, high speed winds and earthquakes.
The Africa including Eastern parts are already water stressed region of the world. It might be due to result of low precipitation in this region and uneven water distribution. In Africa two out of three in rural areas and one out of four in urban areas do not have access safe and clean water2. The water flow in two of three rivers in Tanzania have drastically reduced resulting in water shortage, lack of agriculture production and variation in hydropower projects3. The lack of precipitation in catchment areas, reduced the annual water flow of River Pangani and river Ruvu by 6-9% and 10%, respectively4.