Which purpose is NOT served by the Kainji Dam?

The Kainji Dam, located on the River Niger in Niger State, Nigeria, was commissioned in 1968. Its purposes include electricity generation, fishing, navigation improvement, and research. However, the provision of water for domestic use all over Nigeria is NOT a purpose served by the dam.

The Kainji Dam serves the following purposes:

• Generation of electricity - the Kainji hydroelectric power station was Nigeria's first large-scale hydropower facility and supplies electricity to the national grid.
• Fishing facilities - the reservoir (Kainji Lake) created behind the dam supports a significant inland fishery, providing fish for local communities.
• Research facilities - the National Institute for Freshwater Fisheries Research (NIFFR) is located at the dam, conducting research on freshwater ecology and fish production.

The dam does not provide domestic water supply to the entire country. Its reservoir supplies water to nearby communities, but Nigeria's domestic water needs are met by a variety of local sources including boreholes, rivers, and water treatment plants across the country. No single dam could supply domestic water "all over Nigeria" given the country's vast size.