Influence of Spatiotemporal Variability of Rainfall on East African Shared Surface Water Resources (Case of Lake Victoria)

Studying rainfall distribution is important for sustainable water resource control and economic activities. This research explored seasonal and annual spatiotemporal rainfall variability and trends in East Africa and their impacts on Lake Victoria water levels to update information to support planning, management, and improvement of water-dependent socio-economic activities. Surface water observations for both the satellite (DAHITI altimetry) and ground station for 30 years were used in the study. The datasets were normalized, and analysis of rainfall variability and trends was carried out to determine its influence on lake victoria water levels the shared lake of East Africa. Study results showed an rise in water levels in Lake Victoria for the previous 30 years. The precipitation trends indicated a non-significant increase, as verified by Mann Kendall and the linear fit (Sen’s) test. Moreover, there was an obvious variation in seasonal rainfall, where rainfall seasons was varying much compered to dry seasons. Significant correlations were observed between rainfall from Bunjumbura and Gisozi ground-based rainfall stations and Lake Victoria water levels, although a weak relationship exists with other ground-based stations around the Lake Victoria basin. The study concludes that rainfall affects the variations in the lake water levels to a lesser extent; hence, it is recommended considering the analysis of other different water resources in the Lake Victoria catchment, especially inlet rivers and ground water. The evidence acquired from this research will be important for decision-makers to take proper adaptive measures in water resource management.