This report presents a preliminary evaluation of the addition of hydropower at the existing navigation Lock and Dam 5. The study shows that installation of a hydroplant with a 6,000-kW (kilowatt), 8,400-kW, or 10,800-kW nameplate rating is economical. Pertinent data concerning the site and potential hydropower installations are given. Severe environmental impacts are not necessarily associated with construction of a plant of the sizes investigated despite the proxity of the lock and dam to an environmentally sensitive area. The District Engineer recommends that the Corps of Engineers prepare a feasibility report which can serve as a basis for congressional authorization for hydropower plant construction at lock and dam 5.