Jebba dam is located between Niger and Kwara State. Jebba dam is earth and rockfill and is coupled with several auxiliary dams and infrastructure. The main dam is located to the south and its imperviousness is secured by an upstream blanket. It is followed by a lock and the auxiliary concrete dams 4, 3 and 2. Between these auxiliary dams there is a spillway and the powerhouse with water inlet. The emergency reinforced spillway and auxiliary dam 1 are composed of a dike of the same type as the main dam. A saddle dam, of the same type as the main dam, closes a secondary valley. The normal operating level is 103.0 metres.
The powerhouse is equipped with six turbines and six turbine-alternator groups. Each of the propeller turbines is rated at 96.4 MW for a net head and 102 MW at maximum output. The total nominal power installed is 578 MW.
Jebba Dam comprises the civil dam structures, the bottom gated spillway, the hydroelectric powerhouse with turbines, generators, and a navigation lock, with monitoring and control systems to all these, and M&E appurtenant works. These all make up a continuous structure of about 2,000m crest length. The site plan is presented in below. Technical details of the dam are given in below.
The civil dam structures include a main rockfill dam and a saddle dam, and four auxiliary dams comprising an embankment dam and three gravity concrete structures.
The Jebba Dam stores and safely releases water to generate hydroelectric power, provide flood protection and, originally, support navigation.