Maryland has over 3,000 miles of shoreline, all of which are being impacted by climate change and erosion. As sea levels rise our shores are exposed to increasingly frequent and more severe storms. As flooding increases in response to these conditions, we must prepare our shorelines to be more resilient. It can be challenging for waterfront property owners to know the best way to manage their shorelines. Does it make sense to install a hardened structure such as a bulkhead or stone revetment, or is a nature-based shoreline more resilient and cost effective over time? Studies have shown living shorelines are an extremely effective shore erosion control practice with the added benefits of creating water access and improving local water quality. As a result, in 2008 the Maryland Legislature passed the Living Shorelines Protection Act requiring natural solutions to be used by property owners to protect their shorelines, unless they can prove that natural methods would not work.
The State recognizes a variety of shoreline stabilization projects as “living shorelines.” Designs can be highly variable and employ an assortment of materials such as coir logs, shell bags, or structured sills (rock or wood) to hold sediments in place and reduce erosion. However, not all living shorelines are created equal. Underwood & Associates has designated our unique living shoreline designs as “dynamic living shorelines.” Our in-depth understanding of hydrodynamics and ecosystem processes necessitates the incorporation of natural materials found in tidewater to create an accretional environment to stop erosion and build shoreline. These include stone, sand, gravel, vegetation, and wood structures all placed with intention to achieve dynamic equilibrium. One of the most unique and effective features of our shoreline design is the incorporation of “tombolo” shoreline features found naturally along coasts and estuaries globally.
The tombolo landform is a peninsula that connects an island or shoal to the shore. When a tombolo forms in a natural setting it interrupts the long shore wave energy, causing sand to deposit and accrete, forming beaches and marshes. True living shorelines extend from tidewater to the terrestrial landscape, creating the proper angle of repose for shoreline stability. Runoff from the land is fully integrated into the system, as are the energies found in tidewater.
U&A dynamic living shorelines mimic harmonious natural shoreline systems and accommodate anthropogenic impacts, such as erosion from boat wakes and the effects of climate change, making them highly resilient. They account for sea level rise by providing a wetland and submerged aquatic vegetation (SAV) migration corridor comprised of gentle slopes across the headland structures and the beach strands. The gradual slopes provide areas for sand and sediment accretion. The shoreline, including the headland structures, naturally grows vertically over time as native plants trap sediment and use this amassing base to remain in the appropriate water tolerance zone to prevent inundation by rising water levels. This allows wetland species to keep up with sea level rise in a positive feedback loop that enables wetlands and other shoreline vegetation to reinforce their own growth and success. In addition, habitat is also created that enables the settlement of oysters, mussels, and other bivalves, thereby creating a completely new nearshore ecosystem.
Nature is fluid and fluctuating, constantly shifting and adjusting. As a result, the human tendency to create stability and predictability in the built environment rarely translates well to the restoration of natural habitats. Underwood &Associate’s living shoreline design embraces the dynamic, ever-changing aspects of nature. With their sandy coves, billowing meadows of saltmarsh cordgrass dotted with marsh asters, and vegetated headlands speckled with oyster spat just below the water line, our dynamic living shorelines stand out in comparison with other living shorelines. The only thing they will blend in with is nature.