Living Shorelines
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A Living shoreline is a relatively new approach for addressing shoreline erosion and protecting
marsh A marsh is a wetland that is dominated by herbaceous rather than woody plant species.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p Marshes can often be found at ...
areas. Unlike traditional structures such as bulkheads or seawalls that worsen erosion, living shorelines incorporate as many natural elements as possible which create more effective buffers in absorbing
wave energy Wave power is the capture of energy of wind waves to do useful work – for example, electricity generation, water desalination, or pumping water. A machine that exploits wave power is a wave energy converter (WEC). Waves are generated by wind p ...
and protecting against shoreline erosion. The process of creating a living shoreline is referred to as
soft engineering Regarding the civil engineering of shorelines, soft engineering is a shoreline management practice that uses sustainable ecological principles to restore shoreline stabilization and protect riparian habitats. Soft Shoreline Engineering (SSE) uses th ...
, which utilizes techniques that incorporate ecological principles in shoreline stabilization. The natural materials used in the construction of living shorelines create and maintain valuable habitats. Structural and organic materials commonly used in the construction of living shorelines include sand,
wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...
plants, sand fill, oyster reefs, submerged aquatic vegetation, stones and coir fiber logs.


Benefits and ecosystem services

*
Shoreline stabilization A shore or a shoreline is the fringe of land at the edge of a large body of water, such as an ocean, sea, or lake. In physical oceanography, a shore is the wider fringe that is geologically modified by the action of the body of water past a ...
* Riparian and intertidal protection *
Water quality Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...
improvements from upland run-off
filtration Filtration is a physical separation process that separates solid matter and fluid from a mixture using a ''filter medium'' that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filter ...
* Terrestrial and
aquatic habitat Marine biology is the scientific study of the biology of marine life, organisms in the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies s ...
creation * Absorption of
wave energy Wave power is the capture of energy of wind waves to do useful work – for example, electricity generation, water desalination, or pumping water. A machine that exploits wave power is a wave energy converter (WEC). Waves are generated by wind p ...
, leading to reduced erosion rates * Preservation of natural shoreline exchanges * Enhancement of
fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both ...
feeding and breeding habitat * Adaptability and use in a wide range of environments * Potential for less associated costs compared to traditional structures such as seawalls and bulkheads * Creates and preserves nursery and critical feeding habitats for aquatic life * Allows for a more natural
aesthetic Aesthetics, or esthetics, is a branch of philosophy that deals with the nature of beauty and taste, as well as the philosophy of art (its own area of philosophy that comes out of aesthetics). It examines aesthetic values, often expressed th ...
display than traditional structures


Design

Many factors need to be addressed when preparing a living shoreline project. Permitting requirements and appropriate restoration strategies for a particular habitat are two critical topics for consideration before construction begins.


Planning and implementation steps

''1. Analysis of the site:'' The bank
erosion Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distin ...
rate, elevation level, vegetation, wave energy, wind patterns, wave activity and soil type of the proposed site need to be examined to determine if it is an appropriate area for living shoreline stabilization. Restoration plans of stabilization activities are designed upon completion of the initial site analysis. ''2. Permitting:'' Before any implementation begins, permits should be applied for and obtained through the appropriate regulatory agencies. All project plans need to be in compliance with local, state and federal laws before any construction begins to avoid legal issues and ensure long-term sustainability. ''3. Site preparation:'' Once the necessary permits are obtained, preparation begins by clearing all debris, unstable trees and existing failing structures, such as bulkheads, from the site. In addition, any issues regarding stormwater runoff must also be addressed prior to the installation of a living shoreline. ''4. Project installation:'' Generally, living shoreline structures will include planting marsh, riparian, or other types of aquatic vegetation. Bio-logs, organic fiber mats and oyster shells are also readily used materials throughout installation. ''5. Maintenance and monitoring:'' The restored habitat area should be regularly monitored upon completion to obtain data on project successes. The collection of such data will improve construction and implementation strategies of future projects. The site should also be maintained by replanting necessary vegetation, removing debris and adding sand fill when appropriate. The materials should also be monitored to ensure they are staying in place and achieving desired shoreline stabilization goals.


Materials


Vegetation zone

* ''Clean dredge material and sand fill'' are generally used to construct a rolling slope to weaken wave energy and provide an area to plant vegetation. Regrading, filling and replanting native vegetation can occur on sites that do not have a bulkhead or on sites where bulkheads have been removed. If removing the bulkhead is not feasible, another option is to fill sand in front of the structure and regrade and replant vegetation on the shoreline and embankment. * ''Roots'' from trees and grass stabilize the riparian area above high tide by gripping the soil. Such activity results in bank erosion minimization, wildlife habitat creation and upland runoff filtration. The type of plants that make up common riparian zones typically include grasses, shrubs and woody trees but the species of each are dependent on the naturally occurring vegetation of the area.


Wetland and beach areas

* '' Breakwaters'' provide erosion control and facilitate habitat development by breaking up wave activity in open-water areas. These structures, made with rock and
oyster Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not al ...
spat, should be placed in areas of medium to high wave energy and arranged parallel to the bank. Once implemented, the area around the shoreline should be calmer than before which can allow for the creation of marsh and intertidal habitat through the replanting of marsh grasses and other submerged aquatic plants. * ''Filter fabric'' is a key element in minimizing soil loss under rocks. This porous material made from natural elements is commonly implemented under breakwaters and rock sills or other hybrid living shoreline locations. * '' Geotextile material tubes'' measure about 12 feet in diameter, are filled with sediment and aligned with the shoreline to weaken wave energy and protect against erosion. These tubes facilitate oyster reef development and create areas to dispose of new dredge material. * ''Low-crested rock sills'' are formed by the parallel arrangement and underwater placement of single rocks along shorelines and marshes. The rocks decrease erosion rates in these areas by dispelling oncoming wave energy. The placement of these sills are no greater than 6 to 12 inches over the mean high water mark and typically divided into sections to allow for the passing of boats, large waves and wildlife. * '' Mangroves'' play a critical role in shoreline stabilization through the trapping of nutrients and sediments and dissipation of wave energy administered by their extensive root system. The incorporation of mangroves with living shorelines could play a large role in decreasing erosion rates since they naturally occur in subtropical and estuarine tropical areas. More specifically, mangroves are typically found in southern Florida, the Caribbean and some areas of southern Louisiana. * ''Marsh grasses'' are generally planted up to the mean high tide line and in the water of the intertidal zones to break up wave energy, provide fish and wildlife habitat and improve water quality through upland runoff filtration. Studies show that plantings may show more success when administered in the spring in areas with existing marsh, mild wind conditions and surrounding areas of less than 3 miles of open water. * ''Natural bio-logs/fiber logs'' can be used to reduce bank erosion and stabilize inclines by implementation at the bottom of a slope or in the water which is formed to the bank line and secured in place. The coconut fiber and netting are biodegradable and work to grab sediment, hold moisture to facilitate vegetative growth, and allow stability of the bank while roots develop. * ''Natural fiber matting'' can be made from a combination of biodegradable, organic mediums but is primarily made from jute, straw, coir fiber or wood. Placing such matting over an abrupt eroding slope minimizes sediment loss and catches sediments otherwise transported by wave dynamics. Natural fiber matting can also be implemented with riparian vegetation or marsh grass plantings to improve bank stabilization. * ''Rock footers'' are small quantities of boulder or rock intended to enhance bank stabilization and add additional support to bio-logs. Rock footers can also be used to support the structure of the biodegradable fiber logs, so that they do not fall out into steeper areas of the bank. * ''Rubble and recycled concrete'' can be used to form a breakwater offshore of a living shoreline site to refract wave energy before it hits the area. The addition of oyster spat these breakwaters can simultaneously enhance water quality and facilitate habitat growth.


Submerged aquatic zone

* '' Oyster shell reefs'' are another option when creating living shorelines. Oysters are critical in enhancing water quality and providing habitat to fish species, so creation of oyster reefs to decrease shoreline erosion rates have many added benefits. In addition, the establishment of oyster reefs play a role in protecting valuable aquatic vegetation of the marine ecosystem. To ensure a healthy reef, only clean oyster shells that have been sitting in the sun for adequate time should be used in the construction process. * ''Reef balls of oysters'' can achieve similar outcomes as oyster shell reefs but have a different implementation process. This type of artificial reef is made up of small, hallow concrete balls that facilitates the build-up of oyster shells as oyster spat take hold on the outside of the structure. An advantage of this implementation strategy is that it decreases poaching of oysters which can be a common obstacle in living shoreline construction that use oyster shells. * ''
Seagrass beds A seagrass meadow or seagrass bed is an underwater ecosystem formed by seagrasses. Seagrasses are marine (saltwater) plants found in shallow coastal waters and in the brackish waters of estuaries. Seagrasses are flowering plants with stems and ...
'' create natural buffer zones against shoreline erosion when implemented in association with living shorelines. In addition, seagrass beds enhance water quality, improve sediment stabilization, supply habitat and food for aquatic organisms and dissipate high-energy waves.


Project Examples

* VIMS teaching marsh, Gloucester Point, Virginia * Jamestown 4-H Camp,
James River The James River is a river in the U.S. state of Virginia that begins in the Appalachian Mountains and flows U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed April 1, 2011 to Chesapea ...
, James City County, Virginia * The Hermitage Museum and Gardens,
Norfolk, Virginia Norfolk ( ) is an independent city in the Commonwealth of Virginia in the United States. Incorporated in 1705, it had a population of 238,005 at the 2020 census, making it the third-most populous city in Virginia after neighboring Virginia Be ...
*
Longwood University Longwood University is a public university in Farmville, Virginia. Founded in 1839, it is the third-oldest public university in Virginia and one of the hundred oldest institutions of higher education in the United States. Previously a college, Lo ...
’s Hull Springs Farm, Westmoreland County, Virginia *
Jefferson Patterson Park & Museum Jefferson Patterson Park & Museum (JPPM) is a 560-acre state park and museum located along the Patuxent River in St. Leonard, Calvert County, Maryland. The property of JPPM was given to the state of Maryland by Mary Marvin Patterson in 1983 in h ...
,
Calvert County, Maryland Calvert County is located in the U.S. state of Maryland. As of the 2020 census, the population was 92,783. Its county seat is Prince Frederick. The county's name is derived from the family name of the Barons of Baltimore, the proprietors of t ...
*
South River Federation In 2019, Arundel Rivers was formed by joining South River Federation with the West Rhode Riverkeeper, Inc. Located in Edgewater, Maryland, USA, the Arundel Rivers Federation, Inc. is a grassroots organization of more than 500 members whose goal is ...
, MD * St John’s College,
Annapolis, Maryland Annapolis ( ) is the capital city of the U.S. state of Maryland and the county seat of, and only incorporated city in, Anne Arundel County. Situated on the Chesapeake Bay at the mouth of the Severn River, south of Baltimore and about east o ...
* Magothy Beach Road,
Pasadena, Maryland Pasadena is a census-designated place (CDP) in Anne Arundel County, Maryland, United States. The population was 24,287 at the 2010 census. The areas of Lake Shore, Riviera Beach and Pasadena are collectively referred to as Pasadena by residents ...
*
San Francisco Bay San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, and Oakland. San Francisco Bay drains water from a ...
*
Piscataway Park Piscataway Park is a National Park Service-protected area located southwest of downtown Washington, D.C. in and around Accokeek, Maryland. It protects the National Colonial Farm, Marshall Hall, and the Accokeek Creek Site. The park is locate ...
,
Potomac River The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved Augus ...
, Maryland *
Delaware Delaware ( ) is a state in the Mid-Atlantic region of the United States, bordering Maryland to its south and west; Pennsylvania to its north; and New Jersey and the Atlantic Ocean to its east. The state takes its name from the adjacent Del ...


References


External links


The North Carolina Coastal Federation



Virginia Institute of Marine Science: Center for Coastal Resources Management

The Chesapeake Bay Foundation

Florida Sea Grant

Mississippi-Alabama Sea Grant

Partnership for the Delaware Estuary
{{Coastal management Coastal engineering