Umudike Journal of Engineering and Technology

Management of water resources for different purposes like domestic water supply, municipal, irrigation and hydropower generation require optimization techniques for efficient reservoir operation. Optimization model was developed to maximize mean monthly yield from the Kainji hydropower reservoir, subject to operations and ecological integrity constraints. Two reservoir optimization scenarios were considered: scenario 1, reservoir yield with only operation constraints and scenario 2, with both operation and ecological integrity constraints. The ecological integrity indicators measured at the power intake and boatyard were regressed against storage while that of turbine discharge and tailrace locations were regressed against release. The regression equations generated were used as part of the constraints together with World Health Organization (WHO) standard for freshwater quality and Washington Department of Ecology Sediment Quality Guidelines (WDOE SQG) for heavy metals. Relationship was also established between the mean monthly storage and fish population and the equation generated was used as part of the model constraints. The model was solved using Language for INteractive General Optimization (LINGO) version 17.0 software for the mean monthly reservoir operation. Results of the relationship between the ecology integrity indicator parameters with storage and release at all the locations were found to be linearly related with the coefficient of determination (R²) varying between 0.76 and 0.98. The optimum yields of 1761.19 and 1590.49 Mm³ can be withdrawn from the reservoir with a live storage of 12000 Mm³ at the Kainji station with and without considering the effect of ecological integrity constraints respectively. The optimum yields can be used to generate more energy at the station without impacting negatively on the reservoir ecological integrity.