BENEFICIAL USE OF DREDGED MATERIALS FOR EROSION PREVENTION AND HABITAT RESTORATION IN COASTAL MISSISSIPPI

Thousands of cubic yards of dredged sediments are collected from Mississippi’s coastal waters each year. The vast majority of this material is either stockpiled or dumped at open-water disposal sites. The objective of this project is to demonstrate the potential beneficial uses of this resource for coastal restoration and erosion control purposes. The Mississippi Department of Marine Resources and its consultant, Eco-Systems, Inc., are carrying out a coastal restoration demonstration project at Cedar Point Landing on the western shore of St. Louis Bay, in Hancock County, Mississippi. The goal of this project is to use sediments dredged from a local marina access inlet to construct a new marsh area nearby. The intended purposes of this man-made marsh are (1) to restore eroded coastal habitat and (2) to protect a local decaying sea wall from further destruction. The project’s scope of work is broken into several phases, including organization, assessment, development, demonstration, and long-term management. As a part of the assessment phase, sediment cores were collected from both the proposed dredging and dredge placement areas. Sediment layers within each core were evaluated geotechnically to characterize historical and current grain-size distributions and associated depositional energy levels. Field observations were also made of current vegetation and ecological conditions in the proposed dredge placement area in order to better design the man-made marsh. Data gathered from this demonstration project will be used in the development of a 20-year regional Master Plan that will allow coastal Mississippi cities and counties to utilize dredge materials for erosion protection and restoration of impaired, damaged, or disappearing habitat.