$320M Second Phase of Louisiana Navigation Canal Lock Complex Moves Ahead

The state of Louisiana earlier this month marked the start of construction’s second phase of the Houma Navigation Canal (HNC) Lock Complex. Officials estimate that the HNC’s system of levees, floodgates and locks will provide protection to roughly 2,000 sq mi of land and 200,000 residents in Terrebonne and Lafourche parishes from storm surges.

“Today’s groundbreaking brings us one step closer to completing the Morganza-to-the-Gulf system and enhancing the protection against hurricanes and other major storms for the residents of Terrebonne and Lafourche parishes,” said Gordon Dove, chairman of the Coastal Protection and Restoration Authority (CPRA), in a press release.

Acting as the state’s entity to develop, implement, and enforce measures of its protection and restoration Master Plan, CPRA is tasked with managing the construction of the project. The U.S. Corps of Engineers maintains the HNC itself and will retain operational responsibility of the lock complex structure when construction is completed.

Sealevel Construction, Inc., Thibodaux, La., was named the project’s general contractor. Slated for completion by April 2028, the project is estimated at $320 million. Kathleen Rodrigue, a company spokesperson, said Sealevel is responsible for the construction of the structural portion of the project, while Rigid Constructors of Lafayette, La., will lead dredging work.

While self-performing site work, Sealevel will additionally construct the coffer damns and two sector gates, with an estimated 55,000 cu yds of concrete. Sealevel will install pipe, timber, concrete and sheet piles, with the largest piling measuring 184-ft long and 30 in. in diameter.

The HNC Lock Complex will aim to prevent saltwater from entering the Terrebonne Basin while also distributing freshwater into estuaries to promote growth of thousands of wetland acres, improving conditions for wildlife and area fisheries. 

“Coordination by state and federal agencies and elected officials at every level got us where we are today, breaking ground on the second phase of the HNC Lock Complex project,” said Louisiana Gov. Jeff Landry in a CPRA press release. “I want to express my gratitude to everyone from Terrebonne, CPRA, the Corps, and our state and federal legislators for acknowledging that the communities, cultures and businesses thriving in south Louisiana are invaluable and must be continuously protected.”

The HNC Lock Complex, to measure 110 ft across and 800 ft in length, will feature inland and Gulf-side sector gates on each side and will connect to the Bubba Dove barge floodgate by a floodwall spanning the channel. Together, the structures will allow for large ship passage. In addition to constructing the lock chamber itself, Phase 2 components include construction of an operational area, control building and 175-ft access bridge. The contractor will dredge an estimated 135,000 cubic yards of material that will be used to shore up 15 acres of marsh habitat.

In a press statement, CPRA Board Member Anthony Alford said “It’s difficult to express just how exciting today is for the people of Terrebonne Parish and the surrounding ecosystem. This project has been in the works for well over a decade, and there have been times where I’ve wondered if I would ever see it completed.

“This project is the lynchpin of the entire Morganza-to-the-Gulf Hurricane Risk Reduction Project,” Alford added. “The ability to let fresh water flow freely throughout the canals and tributaries of Morganza that have been decimated by saltwater will breathe new life into these waterways and allow the areas to flourish once more.”