• living shoreline
    Aquatic plants are an essential part of most living shorelines.

    Photograph by James P. Blair

    But Who Ate All the Oysters?
    Scientists on Dauphin Island in the U.S. state of Alabama have built breakwaters using millions of oyster shells. They hope that algae, worms, barnacles, fish, and shellfish will colonize the shells, creating a unique type of living shoreline. Dauphin Island was seriously damaged by Hurricane Gustav in 2008, and engineers hope the oyster breakwaters will reduce the impact of future storms in the area.

    A living shoreline is a way of managing coastal areas to protect, restore, or enhance the habitat. This is done through the placement of plants, stone, sand, and other materials. Living shorelines do not interrupt natural relationships between land, wetlands, and bodies of water.

    Wetlands

    Wetlands around the world have been damaged by dredging (digging). Most dredging is done to develop urban areas or expand ports. Dredging and drying a wetland can create more land for homes, businesses, or agriculture. Dredging a wetland near a harbor can allow more ships to dock, increasing the economic activity of the area. Dredging a harbor can also deepen the port, which allows larger ships, with more cargo, to dock.

    Wetlands play an important natural role in coastal ecosystems. They prevent erosion of the land. Plants and trees anchor the soil and prevent it from washing out to sea. A wetland barrier between developed inland regions and the coast can protect fertile soil for agriculture, as well as development and recreation.

    Wetlands also protect coastal areas from powerful storm surges. Storm surges are the waves that follow a hurricane or typhoon as it makes landfall. Storm surges can be more than a meter (three feet) tall. Hurricane Katrina, which devastated the U.S. city of New Orleans, Louisiana, in 2005, had a storm surge of about 7.5 meters (25 feet). Wetlands, with their spongy soil, absorb the energy and water of a storm surge. They also slow the surge. This protects homes, businesses, and agricultural areas.

    Wetland habitats help clean waterways. Oysters, for instance, live in coastal wetlands and bays. Oysters are filter feeders. As they absorb nutrients from the water, they also absorb runoff and pollutants.

    Wetlands also provide a habitat for a wide variety of organisms. Some organisms are commercially important to people, such as fish or crabs. Others play an important role in the coastal food web, such as seagrass, snails, or wading birds.

     

    Protection

    When people develop coastlines, they often protect the shoreline—and their property—by constructing rock, wood, or plastic seawalls. A seawall is a large, sturdy structure built to prevent erosion and damage from ocean waves. It extends, sometimes for kilometers, along a shoreline.

    Constructing a seawall usually involves removing coastal vegetation such as seagrass, mangrove trees, and cattails. Without these plants, the biodiversity of the region shrinks. Insects, snails, and shrimp no longer have a reliable source of food. Birds and fish that prey on the insects or snails migrate elsewhere. The population of larger predators, such as muskrats or alligators, may fall sharply.

    Living shorelines protect against erosion without removing vegetation or damaging coastal ecosystems. Unlike seawalls, living shorelines can adjust their height and width to the season or weather. They can expand during wet seasons and reduce their fertility during dry seasons. Living shorelines can be constructed by individuals, communities, or the government.

    Goose Creek Tidal Wetlands Bank in the U.S. city of Chesapeake, Virginia, is a 4.2-hectare (10.4-acre) wetland. It was created by the Virginia Department of Transportation in 1982. That year, the department planned to build a new highway. The Goose Creek Tidal Wetlands were created to make up for wetland losses that would occur during highway construction. The government planted five species of salt marsh plants in the area. These plants were mostly reeds and cordgrass. The government then protected the wetlands from development.

    Attracted by the new salt marsh, coastal species migrated to Goose Creek. Scientists have now identified 21 species of fish, including bass and anchovy, using the marsh. Invertebrates, such as shrimp and clams, are also part of the wetland ecosystem.

    Types of Living Shorelines

    There are many types of living shorelines. The type depends on the reason for creating it and the type of ecosystem involved.

    Sometimes, living shorelines are built along recreational beaches to prevent erosion of sand and preserve the beach. This type of living shoreline may involve simply adding sand to the beach. It may also involve planting beachgrass to stabilize the sand, or building stone breakwaters. Breakwaters are structures placed offshore to reduce the power of incoming waves. This protects the beach from erosion. Breakwaters have the added benefit of creating calm water for swimming.


    A living shoreline may be created along a river for recreational and commercial use. This type of living shoreline may include adding large rocks to the river bank. Frogs, insects, and plants live around river rocks. Moss and grasses help anchor sediment to the river bank. Stable river banks help reduce flooding and create a healthy river environment, allowing for sport fishing and expanded freshwater fisheries.

    Some coastal communities create living shorelines to support or expand ecosystems that are already in place. Fringe marshes are an example of this type of living shoreline. Fringe marshes expand the natural ecosystem of a tidal marsh or swamp.

    Creating fringe marshes may involve planting marsh grasses on the existing shoreline. The existing shoreline may also be expanded by creating sandbars or coastal area. Then, plants such as cattails, mosses, and sedges are planted. These attract insects. Larger predators such as birds may follow, building their nests among the plants and creating a healthy wetland habitat.

    Many living shorelines include permanent support structures. These include:

    • revetments: sloping structures placed directly on the shoreline. Revetments are usually made of riprap, a collection of large rocks or concrete fragments. Revetments are heavy “armor” for the shoreline.
    • breakwaters: freestanding structures made of stone, sand, or other material placed offshore to reduce the power of incoming waves.
    • sills: similar to breakwaters, but placed closer to shore.
    • spurs: similar to breakwaters and sills, but attached to the shoreline or another structure.
    • groins: large structures that extend straight out from the shoreline. Unlike seawalls, groins are perpendicular to the shore. Groins are usually made of concrete, wood, or rock. They often look like piers, and people can walk or even fish on them. Groins are usually built in groups, designed to protect the groin fields, or shoreline between them.

     

  • Term Part of Speech Definition Encyclopedic Entry
    agriculture Noun

    the art and science of cultivating the land for growing crops (farming) or raising livestock (ranching).

    Encyclopedic Entry: agriculture
    anchor Verb

    to hold firmly in place.

    anchovy Noun

    small food fish.

    bass Noun

    type of popular game fish, found in both ocean and freshwater environments.

    bay Noun

    body of water partially surrounded by land, usually with a wide mouth to a larger body of water.

    Encyclopedic Entry: bay
    biodiversity Noun

    all the different kinds of living organisms within a given area.

    Encyclopedic Entry: biodiversity
    breakwater Noun

    a manmade wall rising from the sea floor that protects a harbor or beach from the force of waves.

    cargo Noun

    goods carried by a ship, plane, or other vehicle.

    cattail Noun

    aquatic plant.

    coast Noun

    edge of land along the sea or other large body of water.

    Encyclopedic Entry: coast
    concrete Noun

    hard building material made from mixing cement with rock and water.

    cordgrass Noun

    aquatic plant.

    devastate Verb

    to destroy.

    development Noun

    construction or preparation of land for housing, industry, or agriculture.

    dock Verb

    to bring and secure a ship or boat to a space or facility.

    dredge Verb

    to remove sand, silt, or other material from the bottom of a body of water.

    economic Adjective

    having to do with money.

    ecosystem Noun

    community and interactions of living and nonliving things in an area.

    Encyclopedic Entry: ecosystem
    enhance Verb

    to add to or increase in worth.

    erosion Noun

    act in which earth is worn away, often by water, wind, or ice.

    Encyclopedic Entry: erosion
    expand Verb

    to grow.

    fertile Adjective

    able to produce crops or sustain agriculture.

    filter feeder Noun

    aquatic animal that strains nutrients from water.

    fishery Noun

    industry or occupation of harvesting fish, either in the wild or through aquaculture.

    flood Noun

    overflow of a body of water onto land.

    Encyclopedic Entry: flood
    food web Noun

    all related food chains in an ecosystem. Also called a food cycle.

    Encyclopedic Entry: food web
    freshwater Noun

    water that is not salty.

    fringe marsh Noun

    wetland area between a swamp or tidal marsh and dry land.

    groin Noun

    large structure that extends out from a shoreline, built to prevent erosion.

    groin field Noun

    area of protected shoreline between groins, or large structures that extend from the shoreline.

    habitat Noun

    environment where an organism lives throughout the year or for shorter periods of time.

    Encyclopedic Entry: habitat
    harbor Noun

    part of a body of water deep enough for ships to dock.

    Encyclopedic Entry: harbor
    hectare Noun

    unit of measure equal to 2.47 acres, or 10,000 square meters.

    highway Noun

    large public road.

    hurricane Noun

    tropical storm with wind speeds of at least 119 kilometers (74 miles) per hour. Hurricanes are the same thing as typhoons, but usually located in the Atlantic Ocean region.

    invertebrate Noun

    animal without a spine.

    living shoreline Noun

    method of creating coastal land by using stones and marine grasses to trap soil, sand, and mud.

    Encyclopedic Entry: living shoreline
    mangrove Noun

    type of tree or shrub with long, thick roots that grows in salty water.

    migrate Verb

    to move from one place or activity to another.

    moss Noun

    tiny plant usually found in moist, shady areas.

    nutrient Noun

    substance an organism needs for energy, growth, and life.

    Encyclopedic Entry: nutrient
    oyster Noun

    type of marine animal (mollusk).

    permanent Adjective

    constant or lasting forever.

    perpendicular Noun

    at a right angle to something.

    pier Noun

    platform built from the shore and extending over water.

    plant Noun

    organism that produces its own food through photosynthesis and whose cells have walls.

    pollutant Noun

    chemical or other substance that harms a natural resource.

    port Noun

    place on a body of water where ships can tie up or dock and load and unload cargo.

    Encyclopedic Entry: port
    predator Noun

    animal that hunts other animals for food.

    prey Noun

    animal that is hunted and eaten by other animals.

    recreational Adjective

    having to do with activities done for enjoyment.

    reed Noun

    grass with tall, strong stalks that grows in marshy ecosystems.

    restore Verb

    to return something to its former status or quality.

    revetment Noun

    structure placed directly on a river bank or shoreline to prevent erosion.

    riprap Noun

    blocks of broken or uncut stone or concrete, placed along river banks or coastal areas to prevent erosion.

    river bank Noun

    raised edges of land on the side of a river.

    runoff Noun

    overflow of fluid from a farm or industrial factory.

    Encyclopedic Entry: runoff
    salt marsh Noun

    coastal wetland that is flooded with seawater, often by tides.

    sand Noun

    small, loose grains of disintegrated rocks.

    sandbar Noun

    underwater or low-lying mound of sand formed by tides, waves, or currents.

    seagrass Noun

    type of plant that grows in the ocean.

    seawall Noun

    barrier built to protect a beach or shoreline from erosion. Also called a bulkhead.

    sedge Noun

    grass-like plant native to wetlands.

    sill Noun

    freestanding structures made of stone, sand, or other material placed close offshore to reduce the power of incoming waves.

    soil Noun

    top layer of the Earth's surface where plants can grow.

    spongy Adjective

    able to absorb and hold liquid.

    sport fishing Noun

    catching fish for competition or recreation.

    spur Noun

    structure made of stone, sand, or other material to reduce the power of incoming waves, connected to a coastline or other structure.

    storm surge Noun

    abnormal rise in sea level accompanying a hurricane or other intense storm. Also called a storm tide.

    Encyclopedic Entry: storm surge
    support structure Noun

    material that helps a natural or manmade object perform a function.

    swamp Noun

    land permanently saturated with water and sometimes covered with it.

    Encyclopedic Entry: swamp
    tidal marsh Noun

    wetland that is regularly flooded by ocean tides.

    transportation Noun

    movement of people or goods from one place to another.

    typhoon Noun

    tropical storm with wind speeds of at least 74 miles (119 kilometers) per hour. Typhoons are the same thing as hurricanes, but usually located in the Pacific or Indian Ocean region.

    urban area Noun

    developed, densely populated area where most inhabitants have nonagricultural jobs.

    Encyclopedic Entry: urban area
    vegetation Noun

    all the plant life of a specific place.

    waterway Noun

    body of water that serves as a route for transportation.

    wave Noun

    moving swell on the surface of water.

    weather Noun

    state of the atmosphere, including temperature, atmospheric pressure, wind, humidity, precipitation, and cloudiness.

    Encyclopedic Entry: weather
    wetland Noun

    area of land covered by shallow water or saturated by water.

    Encyclopedic Entry: wetland
Tell us what you think