Resilient Solutions for Stronger Shorelines

Located on the northwest corner of Lake Pontchartrain in Tangipahoa Parish, the shoreline has sustained significant land loss and erosion over the years from wave impact, logging, coastal storms, subsidence, sea level rise and increased salinity in the lake. Since the area underwent deforestation in the mid-20th century, it has been estimated that the shoreline erodes between 5-14 feet per year, causing extensive land loss. The shoreline is a vital component of the Manchac Landbridge, a critical piece of land separating Lakes Maurepas and Pontchartrain that helps reduce hurricane storm surge for residential communities to the north and west. It also provides a habitat for alligators, snakes, birds and other wildlife.  

Beginning in 2011, we provided design and construction phase services to help combat rapid erosion of the shoreline. Natural barriers including soft foundation soils, trees, stumps and logs created challenges. Because the project was in an actively eroding environment, the team used barges and dredged channels to move and transport project materials and equipment to the site. Ultimately, 1.7 miles of breakwater was constructed with a 20-year design life and gaps spaced to continue to allow for tidal exchange and fish passage.  

After construction was completed in 2011, a significant amount of land began accreting and growing vegetation behind the new breakwaters. By 2017, 47.4 acres of land had naturally amassed with the help of trapped sediment from the nearby Tangipahoa River. Areas near the river have sediment buildup measuring 4 feet thick today.  

This land buildup provides additional wetland habitat in the area that was rapidly losing land and will increase the chances of survival of the shoreline in the face of continued relative sea level rise over time. In 2019, Phase 2 of the project was implemented, which will feature additional breakwater construction in the coming months.