Rehabilitation of an aging spillway

This paper discusses the design and construction of new fixed crest gravity and gated spillway sections for an existing dam owned by Northern States Power Company (NSP)in Wisconsin. The rehabilitation project replaces a flashboard section and steel gates constructed in the 1920s. This work was done without dewatering the reservoir and yet protecting a major fishery. The site constraints, design considerations, construction methods, changed conditions, and solutions are discussed for this project.