CPRA Planning Freshwater Diversion Near Bayou Boeuf Lock

The state of Louisiana’s Coastal Protection and Restoration Authority (CPRA) is proposing to build a freshwater diversion at Bayou Boeuf Lock in Morgan City near Mile 94 on the Gulf Intracoastal Waterway (GIWW) west of Harvey Lock.

According to a CPRA fact sheet, the “Increase Atchafalaya Flow to Terrebonne” project will involve four major features: a diversion at Bayou Boeuf Lock, which will funnel water from the Atchafalaya River into the GIWW at an average discharge rate of 8,000 cubic feet per second (cfs.); the dredging of the GIWW between Bayou Boeuf Lock and Bayou Chene to increase flow capacity; the dredging of Bayou Copasaw and Minor’s Canal to allow for the southward flow of freshwater; and the beneficial use of dredged material for marsh support in the area.

The project is in the engineering phase, and CPRA expects the design to reach the 30 percent mark by early next year.

“CPRA is dedicated to incorporating the input of various stakeholders into the project implementation process,” the agency stated in a project fact sheet. “Throughout the planning and design process, CPRA has met with landowners, natural resource agencies, local officials and coastal user groups to identify key issues that need to be addressed during the project’s design.”

To that end, CPRA and the Gulf Intracoastal Canal Association (GICA) will host a meeting December 13 at the Morgan City Harbor & Terminal District’s facility in Morgan City to discuss the proposed diversion with GIWW stakeholders, answer questions and explore and document potential impacts to navigation. The meeting will begin at 10:30 a.m., and the office is located at 7327 Highway 182, Morgan City, La., 70281.

According to GICA President Paul Dittman, representatives from GICA, the New Orleans Engineer District, the U.S. Coast Guard and CPRA met October 13 to discuss the proposed project and touched on potential waterway impacts, like sedimentation and changes to currents at the approaches to Bayou Boeuf Lock, Bayou Copasaw and Minor’s Creek. The December meeting, Dittman said, is all about bringing all stakeholders to the table early on to identify and address any potential concerns.

There will be a virtual option for the meeting, with details to follow.

According to CPRA, the diversion is expected to mainly carry freshwater and fine sediments into the GIWW and marshes to the south. Modeling so far suggests little impact to the Atchafalaya River. “Potential sedimentation (fines) into adjacent slips, lock approaches and downstream of the GIWW is being investigated,” according to the project fact sheet.

According to CPRA, the project will be designed to divert water during low and moderate flows of the Atchafalaya River and will be “closed before the Atchafalaya River or areas downstream of the diversion reach flood stage.”

The National Fish and Wildlife Foundation awarded CPRA just over $16 million in late 2016 for the engineering and design of the Increase Atchafalaya Flow to Terrebonne project. According to CPRA’s timeline, the agency hopes to initiate construction in the spring of 2026 and complete construction sometime in 2031.