With sea level and storm activities on the rise, researchers at UNH are looking into the best way to protect our coastal salt marshes. Working in collaboration with Great Bay National Estuarine Research Reserve, researchers are able to implement different techniques to prevent salt marsh erosion due to sea level rise. This post is the second of two, highlighting graduate students working on salt marsh resiliency. You can read our first post here.
Grant McKown came to the University of New Hampshire from Georgia, and studied Environmental Engineering at the University of Georgia. He now studies under Dr. Gregg Moore, working towards a Master of Science in Marine Biology. Grant combines his background in engineering and passion in ecology to understand living shorelines as a salt marsh restoration technique.
A living shoreline is a restoration method which utilizes resilience from plants, shellfish or other natural elements to help stabilize coastal shores in a self-sustaining way that has benefits for wildlife. These natural elements are sometimes combined with hard structures such as rip rap rock walls. In New Hampshire’ seacoast, concern about shoreline erosion has sparked interest in this technique. Living shorelines can be used to replace ‘engineered’ shorelines armored with seawalls or large boulders in low wave energy areas. One method utilized here is to replace armored shorelines with salt marshes along with rip rap placed at the seaward edge to protect the marsh against erosion. There have been a handful of recently completed living shoreline restoration projects in the seacoast.
While studies of the effectiveness of living shorelines have been done in southern Atlantic coastal areas, less is known about the effectiveness of this method in the Northeast, which has the added element of snow and ice. By monitoring geochemistry, invertebrates, erosion, decomposition, vegetation, and fish in local living shoreline sites, Grant will evaluate aspects of this restoration technique and how we can improve it. His preliminary results show that vegetation in a living shoreline can recover, but is not as robust as vegetation in an untouched natural salt marsh. Patches of vegetation can develop after planting, requiring replantings after 3-4 years of construction. In addition, soil anoxia, which is an important aspect of a healthy salt marsh ecosystem, can develop in a living shoreline after three years.
Grant recently finished his second summer of field work in and around Great Bay. He has enjoyed learning about salt marshes and their unique challenges when it comes to ecological restoration. He encourages local residents to learn more about coastal resiliency and get involved in volunteering for coastal monitoring programs. We look forward to hearing more from Grant as he continues his studies. Learn more about living shorelines here or go visit one on Great Bay at Wagon Hill Farm, a public land maintained by the Town of Durham.
Picture 1 (below): Grant McKown is a Master of Science graduate student at the University of New Hampshire, studying freshwater and estuarine ecology. Photo courtesy of Grant McKown.
Picture 2 (beow): An example of a highly eroded marsh near Wagon Hill Farm in Durham, NH. Fringe marshes are the most suitable candidate for implementing living shorelines. Photo courtesy of Grant McKown.
Cover photo (above): The living shoreline construction at Wagon Hill Farm in May 2020, a year after construction. Photo courtesy of Grant McKown.