The beaches along the Mississippi Gulf Coast experience constant erosion and deposition due to wave conditions. This shift is exacerbated by ugly and aging outfall pipes that discharge debris-filled rainwater onto beaches.
The Mississippi Department of Marine Resources wanted to reduce the problem by replacing a number of aging outfall pipes with more aesthetically pleasing structures. However, the solution had to be able to withstand the 597-lb/ft² wave pressures that pound local beaches. Precast concrete proved to be the best solution, both aesthetically and structurally, for the multiphase project, as it was the only material that could support this type of abuse.
In the initial phase of the project, the old drainage systems were replaced with new piping, overflow junction boxes, and box-culvert systems to the edge of the sand template, which encompasses the area located 230 ft south of the existing seawall. Three architectural and structural precast concrete wave outfalls were then constructed, combining nine existing and future round pipes into three public walkway structures where visitors can view the beauty of the Sound.
The precast concrete producer assisted in the design of gray-and-tan wave patterns in the panels to blend with the beach color palette. The color patterns flow with spontaneity, like the rolling waves of the Sound. To prevent graffiti from tarnishing the design, the architect chose a factory-applied coating that will prevent any permanent graffiti damage and keep the maintenance costs as low as possible.
The new outfalls now provide increased capacity for the existing storm sewer system, with new oversized box-culvert drainage outlets. They also can be used as a secondary safety measure for Highway 90 drainage through the installation of overflow boxes that allow for constant drainage if primary systems fail.
The innovative precast concrete solution will help to enhance, conserve, and upgrade waterfront areas while improving public amenities and the aesthetics of the beach environment for years to come.