Stormwater Outfalls – Phase I, Biloxi MS
The beaches along the Mississippi Gulf Coast are dynamic coastal systems that experience erosion and deposition of sand depending on wave conditions. Many of the existing outfall pipes and storm drainage structures discharging onto the beach and into the Mississippi Sound are partially to fully clogged with sand and/or damaged and have reached their serviceable life. Direct wave damage and corrosion from salt has taken its toll on many of the outfall locations and the aging infrastructure is in need of replacement.
In an effort to upgrade this infrastructure, Covington Civil and Environmental, in concert with MDMR, provided the necessary permitting, engineering and construction inspection services to combine and reduce the total number of visible outfall pipes along the Coastline. After careful hydraulic studies were completed by Covington nine (9) existing/future round RCP pipes were diverted into three new and distinct box culvert systems that served not only as new and improved drainage for Highway 90, but also as aesthetically pleasing public walkway structures, complete with handrails, inviting all to view the beauty of the Mississippi Sound.
Specific activities after the demolition of the existing systems included hydraulic studies to inform the base system design which required the installation of new overflow structures as required by MDOT, large cast in place junction boxes to accommodate the multiple pipe entries, new RCP infrastructure, the incorporation of aesthetic architectural panels and plantings of sea grasses to reduce windblown sands and re-occurring beach erosion.
Advantages realized by this project include:
- Elimination of unsightly and worn out infrastructure,
- Upgraded and increased drainage for Highway 90,
- Improved public amenities and aesthetics of the beach environment,
- Creation of dune beds with sea oats to deter blowing sands and the burdensome maintenance cost for sand removal on Highway 90.