Laguna Madre Rookery Island Restoration

Project Description

The Navigation District recognizes sediment dredged from the Mansfield Channel as a valuable resource and intends to beneficially use this material to restore sensitive rookery island habitats located within the adjacent Laguna Madre area. Dredged material for this section of the channel has been historically placed in Placement Areas (PAs) 4 through 6, by the U.S. Army Corps of Engineers; however, the formation of protected critical seagrass habitats directly adjacent to these PAs pose challenges for continued use of these areas. This project developed a sediment management plan for dredge material coming from the Mansfield Ship Channel (Laguna Madre side) including the development of sediment management concepts, specifically for the creation and potential expansion of rookery islands. A key step in this process will be the evaluation and minimization of impacts to seagrasses adjacent to the formed placement areas. Several open dredge material placement areas were created south of Mansfield channel, which can be expanded with new dredge material. There are areas with seagrasses and others without seagrasses. This study will begin by focusing on delineating areas of seagrass (and absence thereof) and physical parameters which may be conducive to the health of seagrass beds. The seagrass survey will help to identify opportunities for placement of dredge material. Based on this information, a beneficial use plan may be developed to expand the size of the dredge placement areas close to the south side of the channel and minimize impacts. The successful implementation of this project will require planning, regulatory compliance, engineering analysis and design actions as well as multi-agency coordination, collaboration, and participation. The plan is to expand the placement areas without creating impacts to the existing sensitive habitats.