The Galveston Bay Foundation met with officials from the U.S. Army Corps of Engineers Galveston District last week to view and discuss a dredging project near Carancahua Point in West Galveston Bay on the Gulf Intracoastal Waterway. GBF and many local fishermen have been concerned about the dredge material being placed upon seagrasses that have re-established in the area.
Seagrass is an important and rare habitat in Galveston Bay, as juvenile shrimp, crabs, and fish all use seagrass beds as nursery areas. Galveston Bay had lost over 90% of its seagrasses since the 1950s, but in recent years, seagrasses have begun to return to the bay.
The USACE justified the dredging project under a study done in the Laguna Madre that showed that long term impacts to seagrass from being covered with a thin layer of dredge material would be minimized if the material was placed in the winter months when the seagrass is photosynthetically inactive. However, because seagrass is so rare in Galveston Bay as compared to the Laguna Madre, GBF asked the USACE to carefully review its plans and make changes to further minimize potential impacts to seagrass.
The USACE used, or was scheduled to use, two permitted placement areas (“PA”) in West Bay, PA 63 and PA 62 (please see attached maps of PAs). The USACE has already completed its work in PA 63, but is still scheduled to place a substantial amount of dredge material in PA 62. After GBF representatives visited the site and met with the USACE last week, the USACE has agreed to make the following changes:
1. The USACE will immediately complete a full seagrass survey at PA 62 prior to any new material being placed there and will follow up with a post-dredging survey in PA 63 to establish dredge material thickness and elevations for long term monitoring.
2. The USACE will monitor impacts at PA 63 where the dredging has already taken place to create a formal record of any long term impacts to the seagrass there.
3. The USACE will create an interagency coordination team (“ICT”) to discuss the dredging on the Intracoastal Waterway between Sabine Lake and Matagorda Bay ahead of time in the future, and will also develop a full monitoring plan for disposal areas PA 63 and PA 62. The team will evaluate the seagrass surveys and the post dredging conditions and make recommendations on how the USACE should monitor and manage operations in PA 62 and 63.
4. The USACE will attempt to minimize impacts to seagrass from the disposal that has yet to occur in PA 62. First, they will take as much as half the dredge material that is still scheduled to be placed in PA 62 and beneficially use it on private property north of the Intracoastal Waterway. Second, for the material that still must go into PA 62, the USACE will ensure its dredge contractor moves the dredge pipe multiple times to make sure no more than a thin layer will be placed onto any one area.
GBF President, Bob Stokes , stated, “I was impressed with the attention the USACE gave this matter. They took our concerns and the concerns of local fisherman seriously and have agreed to make important changes to the project. ” In the meantime, the placement areas will continue to be monitored to ensure the minimization of negative impacts to seagrasses in West Galveston Bay.
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Dredging Today Staff, January 11, 2012; Image: usace