What are Living Shorelines?
Living shoreline projects employ a strategic placement of natural materials, vegetation, rock, and shellfish as a more environmentally-friendly way buffer coastlines from erosion and wave energy. Tidal shorelines are continually eroded by wind and waves, and although this process occurs naturally, human activities like high-speed boating, sand mining and runoff can exacerbate the rate of erosion and disrupt the ecosystem around them. In addition, rising sea levels pose a huge threat to coastlines by increasing erosion, storm inundation, and flooding. Installing living shorelines is a way to work with natural habitats and rising sea levels while still protecting important tidal processes.
Conventional shoreline stabilization methods including bulkheads and revetments (riprap) are a short term solution to protecting the coastline from erosion. They can actually damage shallow tidal zones when waves are reflected back and offer very low habitat value. Not to mention they are far more expensive to install and upkeep! Protecting our shorelines using native trees, shrubs, grasses, and reef forming animals can help combat natural and induced erosion of our coastlines. In addition, this form of stabilization adds multiple benefits back to the environment by encouraging natural processes, as opposed to conventional shoreline stabilization methods.
Common Components of Living Shorelines
Biologs are cylindrical rolls of packed coconut fiber bound together by twine, and they protect shorelines by reducing wave energy. The physical structure of the log functions as a “wave breaker” preserving easily eroded shorelines. Biologs trap sediment and nutrients from land runoff, which helps decrease sedimentation and eutrophication. Additionally, the coconut fiber provides a medium for the establishment of aquatic vegetation, which is continually enhanced by trapped sediment and nutrients. If biologs are used as part of a living shoreline, herbaceous plants can be planted directly inside them. Over five to six years, the biolog will decompose naturally, but the plants’ roots will grow throughout the log to hold the bank or shoreline edge in place.energy and containing lakeshore soil behind them.
|"Walking in eelgrass" by Cory
Janiak. Photo Source
Eelgrass beds are often incorporated into living shoreline projects because they help to stabilize the shore, clean the water, and provide habitats for native species. Eelgrass is a flowering underwater plant that can grow up to 3 feet in length, with rhizomes that anchor the grass into muddy bottoms. Beds of eelgrass filter excess nutrients out of the water and help prevent shoreline flooding by buffering wave action. Unfortunately, we are continually killing off eelgrass from boating, development, pollution. Too many nutrients promote algae growth, which blocks light from reaching the sea grass beds; darkness can kill off the eelgrass, and inevitably, reduce the habitat's biodiversity. Thus, it is crucial that we work to protect and restore eelgrass beds along coastlines.
Like eelgrass, oysters play a critical role in marine habitats. Olympia oysters are native to the Pacific coast of North America, and are rather small at only 2.4 to 3.1 inches in length. The shell can be rounded or elongated, with yellow or brown stripes. Olympia oysters, like almost all other bivalves, are filter feeders. This means that they filter their surrounding water and screen out the phytoplankton they feed on. Just like eelgrass, Olympia's filter between 9 to 12 quarts of water each day, and this is an essential function to keeping marine waters clean. The oyster beds also provide shelter for anemones, crabs, and other small marine life. Bags of oyster shells are often used to protect shorelines because they reduce coastal erosion and filter out pollutants in runoff (Oysters shells used in NC living shoreline project).
Reef balls are artificial reef modules made out of cement, and they are strategically placed in the ocean to mimic natural reef habitats. They are used around the world to restore ailing reefs and create habitats for fish and other marine and freshwater species. However, they are also a great tool for controlling coastal erosion! They can be lined up in an offshore breakwater, grow mangrove trees, or act as a protective near-shore oyster habitat (Artificial reefs used for restoration and erosion prevention).
Living shorelines have many benefits:
- improve water quality by improving natural water filtration
- provide shallow water habitat for diverse assemblages of animals and plants
- help to increase oxygen levels for fish and other aquatic species
- absorb wave energy to protect the shallow sub-tidal zone and underwater grasses
- return habitat connectivity between terrestrial and subtidal communities
Upper Newport Bay Living Shorelines Project
Coastkeeper, in partnership with California State University Fullerton and Anchor QEA, will begin a new restoration project which targets the native Olympia oyster, Ostrea lurida, and native eelgrass, Zostera marina, in an innovative integrated approach in Newport Beach, California. We plan to harness the sediment stabilization characteristics of each to counteract shoreline erosion and provide other critically needed environmental and economic benefits. Orange County Coastkeeper predicts this dual restoration approach will provide exponentially greater protection than individual restoration, with greater ecosystem and economic benefits than currently used man-made erosion prevention structures. We will begin implementation of the project in the summer of 2016 in Upper Newport Bay. Check back soon to find out more ways you can get involved!
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