The Kamehameha Tunnel Waterline project on Oʻahu involved the design and construction of emergency waterline repairs for the Honolulu Board of Water Supply, completed in partnership with Sam O. Hirota, Inc. Work included slip lining approximately 2,200 linear feet of new 30-inch HDPE pipe within an existing 36-inch water main, installing two 30-inch gate valves in Type “A” manholes, and relocating approximately 60 linear feet of an existing 12-inch waterline.

Construction required coordinated pipe fusion and pulling operations from staging areas at both ends of the utility tunnel. Restricted access, confined work areas, and a valve installation along a narrow roadway serving a bus route presented additional challenges. Through careful planning and innovative construction techniques, Koga successfully installed the new pipeline and completed critical connections in a demanding work environment.