Bulkheads are the most commonly used estuarine shoreline stabilization method in North Carolina, but could have deleterious impacts on the marsh habitats where they are being constructed. Potential impacts of bulkheads on marsh ecosystems include cutting off the upland from the intertidal/subtidal region, blocking coastal marsh from transgressing upland, reflecting wave energy to potentially cause increased erosion and sediment scour, and transforming gently sloping shorelines to areas with steep transitions. In addition to quantifying the impact of bulkheads on surrounding estuarine environments, in 2012 researchers from the NCNERR, NOAA, and the University of North Carolina Chapel Hill's Institute of Marine Sciences (UNC-IMS) also worked to construct a demonstration project utilizing a living shoreline design to stabilize an eroding estuarine shoreline. Living shorelines are an alternative to bulkheads and other traditional methods of estuarine shoreline stabilization, and involves natural construction materials and a design that minimizes the potential impact on estuarine ecosystem services and functions. The living shoreline demonstration project provides new data about the effectiveness of living shoreline design and construction techniques, and serves as a visual example as to how shoreline stabilization can be designed to preserve natural habitats and ecosystem functions.
The living shoreline demonstration designed for the Sustainable Estuarine Shorelines project is a novel approach because it uses loose oyster shells rather than hard structures such as bagged oyster shells, coir logs, and granite or wooden breakwaters. This allows the stabilization structure to adapt to changing conditions. The living shoreline demonstration project is constructed with all natural materials, and closely mimics a natural oyster reef, providing similar habitat and ecosystem functions to those found in a natural setting. The demonstration project was constructed on the Rachel Carson Reserve, part of the N.C. National Estuarine Research Reserve, and can be conveniently viewed by coastal decision-makers, developers and contractors, and the public. The collaborative institutional effort demonstrates a sustainable alternative to traditional bulkhead stabilization, and will continue to generate data and research products focusing on the effectiveness of living shoreline stabilization in estuarine environments.
The loose oyster shell that was deposited in 2012 has transformed into a live oyster reef, but the marsh landward of the reef has struggled to thrive. On two different occasions volunteers have planted smooth cordgrass at the site, once in 2014 and again in 2015. You can read about their efforts here.
- Information for property owners about using living shoreline techniques to stabilize an estuarine shoreline is available in the Weighing Your Options handbook.
- Digital Elevation Modeling by NOAA researchers shows how living shoreline changes over time
- Report by Dr. Joel Fodrie (UNC-IMS) on the living shoreline demonstration project construction