Kingstown Port Modernization—Working around a Crumbling Sewer Outfall

As part of the Kingston Port Modernization Design–Build Project located in area in the Bay of Kingstown on the southwest coast of the Island of St. Vincent in the Grenadines, an existing sewer outfall pipeline belonging to Central Water and Sewage Authority (CWSA) had to be decommissioned and replaced with a new sewer pipeline routed on land and offshore. The existing sewer outfall is the only wastewater effluent disposal line for the Kingston District; therefore, interruption of the service had to be kept to a minimum. To address the challenges of installing a new outfall pipe in the marine environment, the design included a new High Density Polyethylene (HDPE) pipe, hydrodynamic modeling for diffuser location, Air Release Valves (ARVs) along the new outfall, and articulated concrete mattress for stability against wave attack in the surf zone. The final design and construction resulted in a successful outfall project able to function in a marine environment.