The work is generally described as the installation of large diameter mainline conduit ranging from 36- inch diameter reinforced concrete pipe to 96-inch wide by 60-inch high reinforced concrete box culverts; Separation drains ranging from 12-inch to 21-inch diameter PVC drain pipe and catch basin connection; Constructing the Bunker Hill Outfall which includes work installing a headwall, baffle apron, flap gate and riprap at the Merrimack River; A large cast-in-place junction structure next to West Street CSO Diversion Station; Work within an earthen levee; support crossings over existing north bank sewer interceptor and other large diameter brick sewers; water main relocations to facilitate new drain installation;
