A bulkhead is a

retaining wall Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. Retaining walls are structures designed to restrain soil to a slope that it would not naturally keep to ...

, such as a bulkhead within a ship or a

watershed Watershed is a hydrological term, which has been adopted in other fields in a more or less figurative sense. It may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, called a "watershe ...

retaining wall. It may also be used in mines to contain flooding. Coastal bulkheads are most often referred to as seawalls, bulkheading, or riprap revetments. These manmade structures are constructed along shorelines with the purpose of controlling

beach A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc s ...

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 d ...

. Construction materials commonly used include wood pilings, commercially developed vinyl products, large

boulder In geology, a boulder (or rarely bowlder) is a rock fragment with size greater than in diameter. Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive. In ...

s stacked to form a wall, or a seawall built of

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...

or another hard substance.

Coastal The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in ...

property owners typically seek to develop bulkheads in an attempt to slow large

landslide Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated slope failures, mudflows, and debris flows. Landslides occur in a variety of environmen ...

erosion caused by

wave In physics, mathematics, and related fields, a wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities. Waves can be periodic, in which case those quantities oscillate repeatedly about an equilibrium (re ...

action. Studies over recent decades have resulted in public awareness as to potential negative effects that bulkheads may bring to beaches and the interconnected

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

areas of fish, plants, and birds. Many states have enacted laws to protect beaches to allow for future use of the beaches, as well as protect these natural habitats. The term bulkhead is also used in a similar but distinct context to refer to large pressure sealing isolation barriers which can be retroactively installed for temporary or permanent use during maintenance or construction activities.

Effects

While bulkheads may serve their purpose to slow erosion at a bluff or

front, they commonly cause a domino effect of change to the beach profile. The increased

reflection caused by their presence can result in an increased re-suspension of

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class ...

in the water in front of the bulkhead. This can lead to more sand being distributed in the alongshore direction, away from the beach profile. Due to coastal littoral drift, the sand would then instead be distributed toward the ends of the bulkheads, leaving larger

gravel Gravel is a loose aggregation of rock fragments. Gravel occurs naturally throughout the world as a result of sedimentary and erosive geologic processes; it is also produced in large quantities commercially as crushed stone. Gravel is classifi ...

and sometimes

bedrock In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of be ...

in place of the once sandy beach. Since sand is a natural habitat for several

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

of fish to lay their eggs and is also the only surface in which eelgrass can take root, these natural processes can no longer take place in this now sand-stripped location. The absence of eelgrass means that the

spawning Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquat ...

habitat for

herring Herring are forage fish, mostly belonging to the family of Clupeidae. Herring often move in large schools around fishing banks and near the coast, found particularly in shallow, temperate waters of the North Pacific and North Atlantic Ocean ...

and the protection for juvenile

salmon Salmon () is the common name for several commercially important species of euryhaline ray-finned fish from the family Salmonidae, which are native to tributaries of the North Atlantic (genus '' Salmo'') and North Pacific (genus '' Onco ...

would no longer be present. This new sand-stripped habitat also encourages other species, such as

kelp Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant - it is a heterokont, a completely unrelated group of organisms. Kelp grows in "underwa ...

, to move in.

Gallery

Image:NorthPadreIslandfig10LG.jpg, Seawall on North Padre Island constructed in the backbeach to protect condominiums from storm waves and beach erosion. Central Texas Image:USGSseawall-lg.jpg, Seawall protecting homes from storm waves and beach erosion. Northwestern Panhandle of Florida Image:fig10-large.jpg, Hard structures, such as the Galveston seawall, can increase erosion of adjacent beaches. Image:seawall-large.jpg, Seawall protecting homes from storm waves and beach erosion. Eastern Panhandle of Florida

References

Shore Stewards News - Bulkheads and Your Beach - PDFShore Stewards News - Creosote - PDF
*Johannessen, J. 2000. *Alternatives to Bulkheads in the Puget Sound Region: What is Soft Shore Protection & What is Not? In: Proceedings of Coasts at the Millennium, Coastal Society's 17th International Conference. July 2000. In Press. *''*Portions of article information obtained from''
(Soft Shore Protection as an Alternative to Bulkheads—Projects And Monitoring - PDF
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External links

*

* ttp://www.ecy.wa.gov/programs/sea/shorelan.html Washington Department of Ecology Website: Washington State Shorelands & Environmental Assistancebr>Beach Nourishment on Puget Sound: A Review of Existing Projects and Potential Applications – PDFAlternative Shoreline Stabilization Evaluation Project – Final Report, Prepared For:. Puget Sound Action Team. P.O. Box 40900 – PDF
Seawalls

Effects

Gallery

See also

References

External links