Longboat Key, FL Fast-Tracked Beach Restoration

Background

The Town of Longboat Key manages 10.2 miles of Gulf of Mexico shoreline in Manatee and Sarasota Counties, FL. The battle of beach erosion in the area is never-ending so the Town requires a strong partner in its efforts. Our team has provided coastal engineering consulting services to the Town in support of the Town’s Beach Management Plan for over 10 years and has helped the Town in the construction of several beach nourishment and coastal stabilization projects. We have also provided program and grant management assistance to help guide and fund their projects.

Approach

In 2021, we served as the Engineer-of-Record and permit agent for the Town’s Beach Nourishment and North End Structural Stabilization Project. The larger project, constructed by Weeks Marine, Inc., involved the dredging of over 700,000 cubic yards of sand from a shallow borrow area 10+ miles from the beach site on Longboat Key, the transport of the sand via scow and tugout, and pumpout of sand to the beach. Our team also served as Engineer-of-Record for two different dredging and beach nourishment projects that excavated the ebb shoal channels of the tidal inlets at either end of Longboat Key (New Pass and Longboat Pass). The combined projects placed over 1M cubic yards of sand along five different segments of the shoreline.

In conjunction with the dredging and sand placement, the highly eroded north end of the island at Longboat Pass was stabilized with the construction of five T-head rock groin structures. These structures were built on top of gravel-fill geotextile mattress foundations. Built in the vicinity of North Shore Road, these structures required 364 marine mattresses, 10,400 tons of armor stone and 1,280 tons of mattress stone. The structures are designed to significantly reduce the erosional conditions at the north end of the island, while still allowing some level of sand transport through the structural field, working with the natural ebb and flow of sand at the north end of the island.

Our team provided design, permitting, construction contract documents, bidding, contract management, construction observation, permit compliance, and post-construction reporting services for all aspects of the projects. With our grant management assistance, the Town was able to secure grants and reimbursements from the Florida DEP, Florida DEM, and FEMA to offset costs.

Results

The final execution of the project included completion of the rock groin structures and all three planned dredge projects, constructed during the same time period to best leverage the available dredge plant. Total cost for the combined projects came in several million dollars under budget and took only seven months instead of the originally anticipated three years. The work, conducted between March and October 2021, was hastened by the presence of contractors being used for similar tasks by other member jurisdictions.

Most recently, we served as the Engineer-of-Record for the New Pass Terminal Groin Rehabilitation Project constructed in 2024. The project sand-tightened the structure to reduce sand losses to New Pass. Ongoing work with the Town includes permit-required annual physical monitoring and a post-Hurricane Debby analysis of the Town’s Gulf shoreline.