Development and management of available and qualitative surface water resources has been a very crucial issue in developing world. To carry out effective societal water demands: for domestic, industrial and agricultural uses, hydropower generation and to protect human settlement from extreme floods; system for water storage and distribution have been developed over the centuries to balance the uneven distribution. Many dams have been constructed and as a result, many downstreams beneficiaries were deprived, due to development upstreams, it is difficult to maintain originl natural flows. There is the need to assess the existing capacity of reservoir in order to determine its ability to meet up existing and planned demands. This work has assessed existing dam and found that it can meet up its planned demands as well as argument to increase demands downstream.This work will assist in training students and staff working in dams and irrigation projects or government officials that are decision makers on issues related to appropriate sharing of natural water resources for most beneficial use.