Northeast Turtle Bay Marsh Creation and Critical Area Shoreline Protection Project (BA-206)

Trigon was the prime contractor/consultant engineer for this Task Order (12FPC219F0165), awarded under our Regional CWPPRA/RESTORE A&E Services IDIQ Contract covering the Gulf Coast states of Texas, Louisiana, Alabama, Mississippi, and Florida. Historic wetland loss in the area occurred in the form of shoreline erosion along Turtle Bay and interior marsh loss. The interior loss was caused by subsidence, sediment deprivation, and the construction of access and pipeline canals. Based on analysis conducted by the United States Geological Survey (USGS), loss rates in the area were estimated to be -0.97% per year for the period 1984 to 2016.

Shoreline erosion along the northeast shore of Turtle Bay, in the area addressed by this project, was approximately 5 feet per year. While this rate may not seem excessive, this reach of shoreline is very narrow and loss of this shoreline would connect Turtle Bay to a large lagoon, greatly altering the hydrology of the marsh north of the project area.

The proposed scope for the project during Phase 0 was determined through analysis of aerial imagery. This scope identified approximately 377 acres of marsh creation and 300 acres of marsh nourishment, based on USGS land/water analysis of the area. It was assumed that areas of water would be considered marsh creation while areas of land would be classified as marsh nourishment. This project was originally scoped to protect approximately 3,000 feet of critical shoreline and install two channel liners to prevent further enlargement of two primary water exchange points.

A&E Services performed on this project ranged from surveying and geotechnical field investigations through design. The final report and design was submitted in January 2022. Construction is pending funding.