Live coastlines are built to counteract coastal erosion from wave action. They are an alternative to gray infrastructure (concrete breakwaters) protecting the land shores from degradation. At the same time, they are a place where new types of habitats are created, and they also protect other coastal ecosystems, such as salt marshes.
Two types of living coastlines are currently built:
a) Natural – using biodegradable organic materials as a skeleton frame structure, oyster reefs, anchored wood piles, etc.
Sediments from water are retained on the skeleton frame structure, and native species are also planted.
b) Hybrid – where the skeleton frame structures are made of concrete thresholds and breakwaters, they can then be planted with native species of crustaceans, including native species of plants.
When designing such solutions, the following factors should be taken into account: biotic (appropriate selection of plant species adapted to given environmental conditions), abiotic (degree of slope, erosion rate, types of sea currents, wave forces, development and use of coastal areas)
Live coastlines protect shoreline from erosion and protect existing coastal habitats, purify water, and retain nutrient-rich soil. They contribute to the protection of fish that use sheltered zones as a spawning ground and space for the development of young fry.
They improve the esthetics of the place.
Properly designed, they do not constitute a barrier to water traffic (moving by boats).
References and additional materials:
https://www.livingshorelinesacademy.org/index.php/for-design-and-constuction
https://www.livingshorelinesacademy.org/index.php/highlighted-projects
https://www.habitatblueprint.noaa.gov/living-shorelines/
An example – Pensacola, Florida
In 2000, the city of Pensacola, Florida began implementing a program to rebuild the lost salt marshes of downtown part of the coastline. The first stage of the investment was to create a breakwater line in the form of the so-called living coastline. The structure was anchored to the bottom of the bay (limestone, recycled concrete and prefabricated concrete blocks were used to build it, and five sandy islands were formed, planted with 41,000 native grass seedlings that build salt marshes). Properly prepared breakwaters became overgrown with oysters, creating new feeding habitats, and many bird species also settled here. The number of blue crabs also increased, which also increased the profits of local fishermen. The vibrant coastline also protected parts of Pensacola from the negative effects of Hurricane Ivan.
http://nrcsolutions.org/pensacola-florida/