December 22, 2015
Posted by: Scott Greene
LSSI has been working on a project to replace our old bulkhead with a more ecologically friendly form of bank stabilization – a living shoreline. The project is the third in a series of pilot projects of this type in Georgia. Several conservation partners are working with us on this, The Nature Conservancy, Sapelo Island National Estuarine Research Reserve, Georgia Department of Natural Resources’ Coastal Resources Division and University of Georgia’s Marine Extension. We have also received some funding for the project from a NOAA (National Oceanic and Atmospheric Administration) grant.
What is a living shoreline? It is a method used to stabilize banks and prevent erosion from tides and surface water runoff. The method involves using bagged oyster shells and marsh plants (Smooth Cordgrass and others) to stabilize the portions of the bank that are covered twice daily by the tide and using other native plantings along the upland portions of the bank to stabilize it during flood tides associated with new and full moon and when there is runoff from heavy rain. By putting oyster shell along the bank, we anticipate creating a living reef on the site. Currently in Georgia, we believe that we have lost 90% of our historic oyster reefs. Our oysters were overharvested in the early 1900s to use in the cannery industry and the shells were not returned to the marshes. Oyster larvae (called spat) require a substrate to settle on, usually other oyster shells. When the oysters are harvested without returning the shells, it diminishes the amount of reefs. Our waters have been tested and they are rich in oyster spat, but we currently have few places for them to settle. We hope to have small growing oysters on the site within a year of construction. Oysters are considered a keystone species in our salt marshes and play an important role in water filtration. Also by building a living oyster reef, we will greatly enhance the fish habitat in the area. We have planted marsh plants along the same zone of the bank as the oysters and believe that they will fill in more along the shoreline in time. Along with the native plants we are putting along the upland, we are beginning to reconnect the upland, marsh and creek ecosystems in this area.
In addition to our conservation partners, volunteers have played a critical role in this process. Coastal WildScapes (www.coastalwildscapes.org) and Americorp volunteer groups have worked tirelessly for many hours to plant and replant native vegetation along the shoreline and to bag oyster shell for the project. Although we had a to buy quite a bit of shell, we have also been able to take advantage of the shell that we have stored on site from our Friday evening oyster roasts. Of the 10,000 bags used in the project, about 2,000 of those came from our stock. So if you have taken part in one of our oyster roasts over the past 5 years or so, you have helped us with this project.
In the future as we are better able to document the success of this new technique through fish sampling and documentation of plant and oyster growth, we hope to continue working with our other partners in developing guidelines to promote living shorelines to a much broader audience.
Updates on our ecological projects can be found on our blog The Natural Notebook.