![Oosterscheldekering, Netherlands](https://upload.wikimedia.org/wikipedia/commons/f/f0/Oosterscheldekering%2C_Netherlands.JPG)
Coastal management is defence against
flooding
A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrolog ...
and
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 ...
, and techniques that stop erosion to claim lands. Protection against rising sea levels in the 21st century is crucial, as
sea level rise
Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...
accelerates due to
climate change
In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
. Changes in sea level damage beaches and coastal systems are expected to rise at an increasing rate, causing coastal sediments to be disturbed by tidal energy.
Coastal zones occupy less than 15% of the Earth's land area, while they host more than 40% of the world population. Nearly 1.2 billion people live within 100 km of shoreline and 100 m of sea level, with an average density 3 times higher than the global average for population. With three-quarters of the world population expected to reside in the coastal zone by 2025, human activities originating from this small land area will impose heavy pressure on coasts. Coastal zones contain rich resources to produce goods and services and are home to most commercial and industrial activities.
History
Coastal engineering of
harbour
A harbor (American English), harbour (British English; see spelling differences), or haven is a sheltered body of water where ships, boats, and barges can be docked. The term ''harbor'' is often used interchangeably with ''port'', which is a ...
s began with the origin of maritime traffic, perhaps before 3500 B.C.
Dock
A dock (from Dutch language, Dutch ''dok'') is the area of water between or next to one or a group of human-made structures that are involved in the handling of boats or ships (usually on or near a shore) or such structures themselves. The ex ...
s,
breakwaters
A breakwater is a permanent structure constructed at a coastal area to protect against tides, currents, waves, and storm surges. Part of a coastal management system, breakwaters are installed to minimize erosion, and to protect anchorages, h ...
and other harbour works were built by hand, often in a grand scale.
Ancient harbour works are still visible. Most of the grander ancient harbor works disappeared following the
fall of the Western Roman Empire
The fall of the Western Roman Empire (also called the fall of the Roman Empire or the fall of Ancient Rome, Rome) was the loss of central political control in the Western Roman Empire, a process in which the Empire failed to enforce its rul ...
.
Most coastal efforts were directed to port structures.
Venice
Venice ( ; it, Venezia ; vec, Venesia or ) is a city in northeastern Italy and the capital of the Veneto Regions of Italy, region. It is built on a group of 118 small islands that are separated by canals and linked by over 400 ...
and its lagoon is an example of measures not related to ports. Protection of the shore in Italy, England and the Netherlands began in the 6th century or earlier. The ancients understood phenomena such as Mediterranean currents and wind patterns and the wind-wave cause-effect link.
The Romans introduced many innovations in harbor design. They built walls underwater and constructed solid
breakwaters
A breakwater is a permanent structure constructed at a coastal area to protect against tides, currents, waves, and storm surges. Part of a coastal management system, breakwaters are installed to minimize erosion, and to protect anchorages, h ...
. These structures were made using
Roman concrete
Roman concrete, also called , is a material that was used in construction in ancient Rome. Roman concrete was based on a hydraulic-setting cement. It is durable due to its incorporation of pozzolanic ash, which prevents cracks from spreading. B ...
. In some cases wave reflection was used to prevent silting. They used surface-height breakwaters to trip the waves before they reached the main breakwater. They were the first dredgers in the Netherlands to maintain the harbour at
Velsen
Velsen () is a municipality in the Netherlands, in the province of North Holland. It is located on both sides of the North Sea Canal.
On the north side of the North Sea Canal there is a major steel plant, Tata Steel IJmuiden, formerly known a ...
. Silting problems there were solved when the previously sealed solid piers were replaced with new "open"-piled
jetties
A jetty is a structure that projects from land out into water. A jetty may serve as a breakwater, as a walkway, or both; or, in pairs, as a means of constricting a channel. The term derives from the French word ', "thrown", signifying somet ...
.
Middle Ages
Attack from the sea caused many coastal towns and their harbours to be abandoned. Other harbours were lost due to natural causes such as rapid silting, shoreline advance or retreat, etc. The
Venetian Lagoon was one of the few populated coastal areas with continuous prosperity and development where written reports document the evolution of coastal protection works. In other words, this is one of the first accounts of the use of a sea wall to protect a coastal settlement.
Modern Age
Little improvement took place beyond the Roman approach to harbour construction after the
Renaissance
The Renaissance ( , ) , from , with the same meanings. is a period in European history marking the transition from the Middle Ages to modernity and covering the 15th and 16th centuries, characterized by an effort to revive and surpass ideas ...
. Then in the early 19th century, the advent of the
steam engine
A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be trans ...
, the search for new lands and trade routes, the expansion of the
British Empire
The British Empire was composed of the dominions, colonies, protectorates, mandates, and other territories ruled or administered by the United Kingdom and its predecessor states. It began with the overseas possessions and trading posts esta ...
through her colonies, and other influences, all contributed to the revitalization of sea trade and a renewed interest in port works.
Twentieth century
Prior to the 1950s, the general practice was to use hard structures to protect against
beach erosion or
storm
A storm is any disturbed state of the natural environment or the atmosphere
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmos ...
damages. These structures included
seawall
A seawall (or sea wall) is a form of coastal defense constructed where the sea, and associated coastal processes, impact directly upon the landforms of the coast. The purpose of a seawall is to protect areas of human habitation, conservation ...
s and
revetment
A revetment in stream restoration, river engineering or coastal engineering is a facing of impact-resistant material (such as stone, concrete, sandbags, or wooden piles) applied to a bank or wall in order to absorb the energy of incoming water
...
s or sand-trapping structures such as groynes. During the 1920s and '30s, private or local community interests protected many coastal areas using these techniques on an ad hoc basis. In certain resort areas, structures proliferated to such an extent that the protection impeded recreational uses. Erosion continued, but the structures remained, resulting in a loss of beach area.
The obtrusiveness and cost of these structures led in the late 1940s and early 1950s, to a more dynamic approach. Projects attempted to replicate the protective characteristics of natural beach and dune systems. The resultant use of artificial beaches and stabilized dunes as an engineering approach was economically viable and more environmentally friendly.
Limited knowledge of coastal sediment transport processes often resulted in inappropriate measures of coastal erosion mitigation. In many cases, measures worked locally, but exacerbated problems at other locations -up to tens of kilometers away- or generated other environmental problems.
European Code of Conduct
The essential source on coastal engineering is the ''European Code of Conduct for Coastal Zones'' issued by the
European Council
The European Council (informally EUCO) is a collegiate body that defines the overall political direction and priorities of the European Union. It is composed of the heads of state or government of the EU member states, the President of the E ...
in 1999. This document was prepared by the Group of Specialists on Coastal Protection and underlies national legislation and practice.
The Group of Specialists originated in 1995, pursuant to a decision by the Committee of Ministers of the Council of Europe. It emphasized the need for integrated management and planning, but that coastal areas continued to deteriorate. The Group claimed that this was due to difficulties in implementing the concept of "integrated management". The Group proposed that the
Council of Europe
The Council of Europe (CoE; french: Conseil de l'Europe, ) is an international organisation founded in the wake of World War II to uphold European Convention on Human Rights, human rights, democracy and the Law in Europe, rule of law in Europe. ...
, cooperate with the
Coastal & Marine Union (EUCC)
Coastal & Marine Union (EUCC) is a nonprofit organization with a membership of around 500 institutions, NGOs and experts, in 40 countries. Its network at large involves about 2500 professionals involved in coastal and marine management issues. Fou ...
and
United Nations Environment Programme
The United Nations Environment Programme (UNEP) is responsible for coordinating responses to environmental issues within the United Nations system. It was established by Maurice Strong, its first director, after the United Nations Conference on th ...
(UNEP).
Planning approaches
![Fivepolicies](https://upload.wikimedia.org/wikipedia/commons/9/9f/Fivepolicies.svg)
Five generic strategies are involved in coastal defense:
* Abandonment
* Managed retreat or realignment, which plans for retreat and adopts engineering solutions that accommodate natural processes of adjustment
* Armoring by constructing seawalls and other hard structures
* Construct defenses seaward of the coast
* Adapting vertically by elevating land and buildings
The choice of strategy is site-specific, depending on pattern of sea-level change, geomorphological setting, sediment availability and erosion, as well as social, economic and political factors.
Alternatively,
integrated coastal zone management
Integrated coastal zone management (ICZM), integrated coastal management (ICM), or integrated coastal planning is a coastal management process for the management of the coast using an integrated approach, regarding all aspects of the coastal zone ...
approaches may be used to prevent development in erosion- or flood-prone areas, reducing the need to address the changes.
Growth management
Growth management, in the United States, is a set of techniques used by the government to ensure that as the population grows that there are services available to meet their demands. Growth management goes beyond traditional land use planning, zon ...
can be a challenge for
local authorities
Local government is a generic term for the lowest tiers of public administration within a particular sovereign state. This particular usage of the word government refers specifically to a level of administration that is both geographically-loca ...
who must provide the
infrastructure
Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and priv ...
required by new residents.
Managed retreat
Managed retreat is an alternative to constructing or maintaining coastal structures. Managed retreat allows an area to erode. Managed retreat is often a response to a change in
sediment budget
Sedimentary budgets are a coastal management tool used to analyze and describe the different sediment inputs (sources) and outputs (sinks) on the coasts, which is used to predict morphological change in any particular coastline over time. Within a ...
or to
sea level rise
Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...
. The technique is used when the land adjacent to the sea is low in value. A decision is made to allow the land to erode and flood, creating new shoreline habitats. This process may continue over many years.
The earliest managed retreat in the UK was an area of 0.8 ha at
Northey Island
Northey Island is an island in the estuary of the River Blackwater, Essex. It is linked to the south bank of the river by a causeway, covered for two hours either side of high tide. The island is approximately 1 mile (2 km) to the eas ...
flooded in 1991. This was followed by
Tollesbury
Tollesbury is a village in England, located on the Essex coast at the mouth of the River Blackwater. It is situated nine miles east of the historic port of Maldon and twelve miles south of Colchester.
For centuries Tollesbury, the village of t ...
and Orplands in
Essex
Essex () is a county in the East of England. One of the home counties, it borders Suffolk and Cambridgeshire to the north, the North Sea to the east, Hertfordshire to the west, Kent across the estuary of the River Thames to the south, and G ...
, where the sea walls were breached in 1995. In the
Ebro Delta
The Ebro Delta ( ca, Delta de l'Ebre, ; es, Delta del Ebro, ) is the delta region of the Ebro River ( ca, Ebre, links=no, es, Ebro, links=no) in the southwest of the Province of Tarragona in the region of Catalonia in Spain. It is located o ...
(Spain) coastal authorities planned a managed retreat.
The main cost is generally the purchase of land to be abandoned. Relocation compensation may be needed. Human-made structures that will be engulfed by the sea may need to be removed. In some cases, armouring is used to protect land beyond the area to be flooded. Costs may be lowest if existing defences are left to fail naturally, but the realignment project may be more actively managed, for example by creating an artificial breach in existing defences to allow the sea in at a particular place in a controlled fashion, or by pre-forming drainage channels for created salt-marsh.
Managed retreat has become more of a necessary strategy due to climate change, as adaptation strategies can only do so much to stop sea level rise.
Hold the line
Holding the line typically involves shoreline hardening techniques, e.g., using permanent concrete and rock constructions. These techniques--
seawall
A seawall (or sea wall) is a form of coastal defense constructed where the sea, and associated coastal processes, impact directly upon the landforms of the coast. The purpose of a seawall is to protect areas of human habitation, conservation ...
s,
groynes
A groyne (in the U.S. groin) is a rigid hydraulic structure built perpendicularly from an ocean shore (in coastal engineering) or a river bank, interrupting water flow and limiting the movement of sediment. It is usually made out of wood, concre ...
, detached
breakwaters
A breakwater is a permanent structure constructed at a coastal area to protect against tides, currents, waves, and storm surges. Part of a coastal management system, breakwaters are installed to minimize erosion, and to protect anchorages, h ...
, and
revetments
A revetment in stream restoration, river engineering or coastal engineering is a facing of impact-resistant material (such as stone, concrete, sandbags, or wooden piles) applied to a bank or wall in order to absorb the energy of incoming water a ...
—represent more than 70% of protected shorelines in Europe.
Alternatively, soft engineering techniques supporting natural processes and relying on natural elements such as dunes and vegetation can prevent erosive forces from reaching the back-shore. These techniques include
beach nourishment
Beach nourishment (also referred to as beach renourishment, beach replenishment, or sand replenishment) describes a process by which sediment, usually sand, lost through longshore drift or erosion is replaced from other sources. A wider beach ca ...
and
sand dune stabilization Sand dune stabilization is a coastal management practice designed to prevent erosion of sand dunes. Sand dunes are common features of shoreline and desert environments. Dunes provide habitat for highly specialized plants and animals, including rar ...
.
Historically coastal strategies were heavily based on static structures, while coastal areas otherwise reflect a
dynamic equilibrium
In chemistry, a dynamic equilibrium exists once a reversible reaction occurs. Substances transition between the reactants and products at equal rates, meaning there is no net change. Reactants and products are formed at such a rate that the conc ...
. Armouring often has the unintended consequence of moving the problem to another part of the coast. Soft options such as
beach nourishment
Beach nourishment (also referred to as beach renourishment, beach replenishment, or sand replenishment) describes a process by which sediment, usually sand, lost through longshore drift or erosion is replaced from other sources. A wider beach ca ...
protect coastlines and help to restore the natural dynamism, although they require repeated applications. Maintenance costs can eventually require a strategy change.
Move seaward
In some cases a seaward strategy can be adopted. Examples from erosion include: Koge Bay (Dk), Western
Scheldt
The Scheldt (french: Escaut ; nl, Schelde ) is a river that flows through northern France, western Belgium, and the southwestern part of Netherlands, the Netherlands, with its mouth at the North Sea. Its name is derived from an adjective corr ...
estuary (Nl),
Chatelaillon (Fr) and Ebro delta (Sp).
There is an obvious downside to this strategy. Coastal erosion is already widespread, and there are many coasts where exceptional high tides or storm surges result in encroachment on the shore, impinging on human activity. If the sea rises, many coasts that are developed with infrastructure along or close to the shoreline will be unable to accommodate erosion. They will experience a so-called "coastal squeeze" whereby ecological or geomorphological zones that would normally retreat landwards encounter solid structures and can migrate no further. Wetlands, salt marshes, mangroves and adjacent fresh water wetlands are particularly vulnerable to such a squeeze.
An upside to the strategy is that moving seaward (and upward) can create land of high value which can bring investment.
Limited intervention
Limited intervention is an action taken whereby the management only addresses the problem to a certain extent, usually in areas of low economic significance. Limited intervention often includes the succession of
halosere
In ecology, a halosere is a succession in a saline environment. An example of a halosere is a salt marsh.
In a river estuary, large amounts of silt are deposited by the ebbing tides and inflowing rivers.
The earliest plant colonizers are algae a ...
s, including salt marshes and sand dunes. This normally results in protecting the land behind the halosere, as wave energy dissipates throughout the accumulated sediment and additional vegetation in the new habitat. Although the halosere is not strictly man-made, as many natural processes contribute to the succession, anthropogenic factors are partially responsible for the formation, since an initial factor was needed to help start the process of succession.
Construction techniques
Hard engineering methods
Groynes
![Groyne at Mundesley, Norfolk](https://upload.wikimedia.org/wikipedia/commons/5/54/Groyne_at_Mundesley%2C_Norfolk.JPG)
Groynes are ert or walls perpendicular to the coastline to trap the
sedimentation
Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the ...
of
longshore drift
Longshore drift from longshore current is a geological process that consists of the transportation of sediments (clay, silt, pebbles, sand, shingle) along a coast parallel to the shoreline, which is dependent on the angle incoming wave direction ...
to gradually create a beach and for it ongoing protection by eliminating coastal erosion, often made of greenharts, concrete, rock or wood. Material builds up on the downdrift side, where
littoral drift
Longshore drift from longshore current is a geological process that consists of the transportation of sediments (clay, silt, pebbles, sand, shingle) along a coast parallel to the shoreline, which is dependent on the angle incoming wave direction ...
is predominantly in one direction, creating a wider and a more plentiful beach, thereby protecting the coast because the sand material filters and absorbs wave energy. However, there is a corresponding loss of beach material on the updrift side, requiring another groyne there. Groynes do not protect the beach against storm-driven waves and if placed too close together create currents that carry material offshore. Shapes of groynes can be straight, outwardly curved away in opposite direction from downdrift.
Groynes are cost-effective, require little maintenance and are one of the most common defences. However, groynes are increasingly viewed as detrimental to the aesthetics of the coastline and face opposition in many coastal communities.
Groynes can be considered a "soft" solution because of the beach enhancement.
Groyne construction creates a problem known as terminal groyne syndrome. The terminal groyne prevents
longshore drift
Longshore drift from longshore current is a geological process that consists of the transportation of sediments (clay, silt, pebbles, sand, shingle) along a coast parallel to the shoreline, which is dependent on the angle incoming wave direction ...
from bringing material to other nearby places. This is a problem along the Hampshire and Sussex coastline in the UK; e.g., at
Worthing
Worthing () is a seaside town in West Sussex, England, at the foot of the South Downs, west of Brighton, and east of Chichester. With a population of 111,400 and an area of , the borough is the second largest component of the Brighton and Hov ...
.
Seawalls
Walls of concrete and masonry are used to protect a settlement against erosion or flooding. They are typically about high. Older-style vertical seawalls reflected all the energy of the waves back out to sea, and for this purpose were often given recurved crest walls which increased local turbulence, and thus increased entrainment of sand and sediment. During storms, sea walls help longshore drift.
Modern seawalls aim to re-direct most of the incident energy in the form of sloping revetments, resulting in low reflected waves and much reduced turbulence. Designs use porous designs of rock, concrete armour (
Tetrapods
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct therapsids ...
,
Seabees
United States Naval Construction Battalions, better known as the Navy Seabees, form the U.S. Naval Construction Force (NCF). The Seabee nickname is a heterograph of the initial letters "CB" from the words "Construction Battalion". Depending upon ...
, SHEDs,
Xblocs
An Xbloc is a wave-dissipating concrete block (or "armour unit") designed to protect shores, harbour walls, seawalls, breakwaters and other coastal structures from the direct impact of incoming waves. The Xbloc model was designed and developed b ...
, etc.) with flights of steps for beach access.
The location of a seawall, must consider the swept prism of the beach profile, the consequences of long-term beach recession and amenity crest level, including cost implications.
Sea walls can cause beaches to dissipate. Their presence also alters the landscape that they are trying to protect.
Modern examples can be found at Cronulla (NSW, 1985–6), Blackpool (1986–2001), Lincolnshire (1992–1997) and Wallasey (1983–1993). At
Sandwich, Kent
Sandwich is a town and civil parish in the Dover District of Kent, south-east England. It lies on the River Stour and has a population of 4,985. Sandwich was one of the Cinque Ports and still has many original medieval buildings, including sev ...
the Seabee seawall is buried at the back of the beach under the shingle with crest level at road kerb level.
Sea walls typically cost £10,000 per metre (depending on material, height and width), £10,000,000 per km (depending on material, height and width).
Revetments
Revetments are slanted or upright blockades, built parallel to the coast, usually towards the back of the beach to protect the area beyond. The most basic revetments consist of timber slants with a possible rock infill. Waves break against the revetments, which dissipate and absorb the energy. The shoreline is protected by the beach material held behind the barriers, as the revetments trap some of the material. They may be watertight, covering the slope completely, or porous, to allow water to filter through after the wave energy has been dissipated. Most revetments do not significantly interfere with transport of longshore drift. Since the wall absorbs energy instead of reflecting, the surf progressively erodes and destroys the revetment; therefore, maintenance is ongoing, as determined by the structural material and product quality.
Rock armour
Rock armour is large rocks placed at the sea edge using local material. This is generally used to absorb wave energy and hold beach material. Although effective, this solution is unpopular for aesthetic reasons. Longshore drift is not hindered. Rock armour has a limited lifespan, is not effective in storm conditions and reduces recreational values.
Geotextile tubes
Geotextile tubes or geotubes are large geotextile bags placed at the sea edge filled with locally available sand slurry. This is generally used to absorb wave energy and hold beach material as riprap does. Often referred to as titan tubes as manufactured by Flint Technical Geosolutions. Longshore drift is not hindered. Rock armour has a limited lifespan, is not effective in storm conditions and reduces recreational values.
Gabions
Boulders and rocks are wired into mesh cages and placed in front of areas vulnerable to erosion: sometimes at cliffs edges or at right angles to the beach. When the ocean lands on the gabion, the water drains through leaving sediment, while the structure absorbs a moderate amount of wave energy.
Gabions need to be securely tied to protect the structure.
Downsides include wear rates and visual intrusiveness.
Offshore breakwater
Concrete blocks and/or boulders are sunk offshore to alter wave direction and to filter wave and tide energy. The waves break further offshore and therefore lose erosive power. This leads to wider beaches, which further absorb wave energy.
Dolos
A dolos (plural: dolosse) is a wave-dissipating concrete block used in great numbers as a form of coastal management. It is a type of tetrapod. Weighing up to , dolosse are used to build revetments for protection against the erosive force of ...
has replaced the use of concrete blocks because it is more resistant to wave action and requires less concrete to produce a superior result. Similar concrete objects like Dolos are
A-jack,
Akmon
An akmon is a multi-ton concrete block used for breakwater and seawall armouring. It was originally designed in the Netherlands in the 1960s, as an improvement on the tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting th ...
,
Xbloc,
Tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct theraps ...
and
Accropode.
Cliff stabilization
Cliff stabilization can be accomplished through drainage of excess rainwater of through terracing, planting and wiring to hold cliffs in place.
Entrance training walls
Training walls are built to constrain a river or creek as it discharges across a sandy coastline. The walls stabilise and deepen the channel which benefits navigation, flood management, river erosion and water quality, but can cause coastal erosion by interrupting longshore drift. One solution is a sand bypassing system to pump sand under/around the training walls.
Floodgates
Storm surge barriers, or
floodgates
Floodgates, also called stop gates, are adjustable gates used to control water flow in flood barriers, reservoir, river, stream, or levee systems. They may be designed to set spillway crest heights in dams, to adjust flow rates in sluices and ...
, were introduced after the
North Sea Flood of 1953
The 1953 North Sea flood was a major flood caused by a heavy storm surge that struck the Netherlands, north-west Belgium, England and Scotland. Most sea defences facing the surge were overwhelmed, causing extensive flooding.
The storm and flo ...
and prevent damage from storm surges or any other type of natural disaster that could harm the area they protect. They are habitually open and allow free passage, but close under threat of a storm surge. The
Thames Barrier
The Thames Barrier is a retractable Flood barrier, barrier system built to protect the floodplain of most of Greater London from exceptionally high tides and storm surges moving up from the North Sea. It has been operational since 1982. When n ...
is an example of such a structure.
Soft engineering methods
Beach replenishment
Beach replenishment/nourishment involves importing sand from elsewhere and adding it to the existing beach. The imported sand should be of a similar quality to the existing beach material so it can meld with the natural local processes and without adverse effects. Beach nourishment can be used in combination with groynes. The scheme requires repeated applications on an annual or multi-year cycle.
Dune stabilisation
Stabilising dunes can help protect beaches by catching windblown sand, increasing natural beach formation. Dune stabilisation/sand dune management employs public amenities such as car parks, footpaths,
Dutch Ladders and
boardwalk
A boardwalk (alternatively board walk, boarded path, or promenade) is an elevated footpath, walkway, or causeway built with wooden planks that enables pedestrians to cross wet, fragile, or marshy land. They are also in effect a low type of bridge ...
s to reduce erosion and the removal of sand by humans. Noticeboards, leaflets and beach wardens explain to visitors how to avoid damaging the area. Beach areas can be closed to the public to reduce damage. Fences can allow sand traps to create
blowouts and increase windblown sand capture. Plants such as
Ammophila (Marram grass) can bind the sediment.
Beach drainage
Beach drainage or beach face dewatering lowers the
water table
The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated.
T ...
locally beneath the beach face. This causes
accretion
Accretion may refer to:
Science
* Accretion (astrophysics), the formation of planets and other bodies by collection of material through gravity
* Accretion (meteorology), the process by which water vapor in clouds forms water droplets around nucl ...
of sand above the drainage system.
Beach watertables have an important bearing on deposition/erosion across the foreshore. In one study a high watertable coincided with accelerated beach erosion, while a low watertable coincided with pronounced aggradation of the foreshore. A lower watertable (unsaturated beach face) facilitates deposition by reducing flow velocities during backwash and prolonging laminar flow. With the beach in a saturated state, backwash velocity is accelerated by the addition of groundwater seepage out of the beach within the effluent zone.
However, no case studies provide indisputable evidence of positive results, although in some cases overall positive performance was reported. Long-term monitoring was not undertaken at a frequency high enough to discriminate the response to high energy erosive events.
A useful side effect of the system is that collected seawater is relatively pure because of sand's filtration effect. Such water may be discharged or be used to oxygenate stagnant inland lagoons/marinas or used as feed for heat pumps, desalination plants, land-based aquaculture, aquariums or swimming pools.
Beach drainage systems have been installed in many locations around the world to halt and reverse erosion trends in sand beaches. Twenty four beach drainage systems have been installed since 1981 in Denmark, USA, UK, Japan, Spain, Sweden, France, Italy and Malaysia.
Buffer zones
Coastal and estuarine ecosystems act as buffer zones against natural hazards and environmental disturbances, such as floods, cyclones, tidal surges and storms. The role they play is to "
bsorba portion of the impact and thus
essen
Essen (; Latin: ''Assindia'') is the central and, after Dortmund, second-largest city of the Ruhr, the largest urban area in Germany. Its population of makes it the fourth-largest city of North Rhine-Westphalia after Cologne, Düsseldorf and D ...
its effect on the land".
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 ...
s (which include
saltwater swamp
A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
s,
salt marsh
A salt marsh or saltmarsh, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It is dominated ...
es, ...) and the vegetation it supports – trees, root mats, etc. – retain large amounts of water (surface water, snowmelt, rain, groundwater) and then slowly releases them back, decreasing the likeliness of floods. Mangrove forests protect coastal shorelines from tidal erosion or erosion by currents; a process that was studied after the 1999 cyclone that hit India. Villages that were surrounded with
mangrove
A mangrove is a shrub or tree that grows in coastal saline water, saline or brackish water. The term is also used for tropical coastal vegetation consisting of such species. Mangroves are taxonomically diverse, as a result of convergent evoluti ...
forests encountered less damages than other villages that weren't protected by mangroves.
Costs
The costs of installation and operation vary due to:
* system length (non-linear cost elements)
* pump flow rates (sand permeability, power costs)
* soil conditions (presence of rock or impermeable strata)
* discharge arrangement /filtered seawater utilization
* drainage design, materials selection & installation methods
* geographical considerations (location logistics)
* regional economic considerations (local capabilities /costs)
* study requirements /consent process.
Monitoring
Coastal managers must compensate for error and uncertainty in the information regarding the erosive processes. Video-based monitoring can collect data continuously and produce analyses of shoreline processes.
Event warning systems
Event warning systems, such as
tsunami warnings
A tsunami warning system (TWS) is used to detect tsunamis in advance and issue the warnings to prevent loss of life and damage to property. It is made up of two equally important components: a network of sensors to detect tsunamis and a communica ...
and
storm surge
A storm surge, storm flood, tidal surge, or storm tide is a coastal flood or tsunami-like phenomenon of rising water commonly associated with low-pressure weather systems, such as cyclones. It is measured as the rise in water level above the n ...
warnings, can be used to minimize the human impact of catastrophic events that cause coastal erosion. Storm surge warnings can help determine when to close
floodgate
Floodgates, also called stop gates, are adjustable gates used to control water flow in flood barriers, reservoir, river, stream, or levee systems. They may be designed to set spillway crest heights in dams, to adjust flow rates in sluices and c ...
s.
Wireless sensor networks can aid monitoring.
Shoreline mapping
Defining the shoreline is a difficult task due to its dynamic nature and the intended application. The relevant mapping scale is dependent on the context of the investigation. Generally, the coast comprises the interface between land and sea, and the shoreline is represented by the margin between the two. Investigators adopt the use of shoreline indicators to represent the true shoreline position.
Shoreline indicator
![Mcwillizind](https://upload.wikimedia.org/wikipedia/commons/1/1e/Mcwillizind.jpg)
The choice of shoreline indicator is a primary consideration. Indicators must be easily identified in the field and on
aerial photography
Aerial photography (or airborne imagery) is the taking of photographs from an aircraft or other airborne platforms. When taking motion pictures, it is also known as aerial videography.
Platforms for aerial photography include fixed-wing aircra ...
. Shoreline indicators may be morphological features such as the
berm
A berm is a level space, shelf, or raised barrier (usually made of compacted soil) separating areas in a vertical way, especially partway up a long slope. It can serve as a terrace road, track, path, a fortification line, a border/ separation ...
crest, scarp edge,
vegetation
Vegetation is an assemblage of plant species and the ground cover they provide. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic character ...
line,
dune
A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, f ...
toe, dune crest and cliff or the bluff crest and toe. Alternatively, non-morphological features may be used such as water level (high water line (HWL), mean high water line) wet/dry boundary and the physical water line. Figure 1 provides a sketch of the spatial relationships between commonly used shoreline indicators.
The HWL (H in Figure 1) is the most commonly used shoreline indicator because it is visible in the field, and can be interpreted on both colour and grey scale aerial photographs. The HWL represents the landward extent of the most recent
high tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another.
Tide tables can ...
and is characterised by a change in sand colour due to repeated, periodic inundation by high tides. The HWL is portrayed on aerial photographs by the most landward change in colour or grey tone.
Importance and application
The shoreline location and its changing position over time is of fundamental importance to coastal scientists, engineers and managers. Shoreline monitoring campaigns provide information about historic shoreline location and movement, and about predictions of future change. More specifically the position of the shoreline in the past, at present and where it is predicted to be in the future is useful for in the design of coastal protection, to calibrate and verify
numerical models to assess
sea level rise
Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...
, map hazard zones and to regulate coastal development. The location of the shoreline also provides information regarding shoreline reorientation adjacent to structures,
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 shel ...
width, volume and rates of historical change.
Data sources
A variety of data sources are available for examining shoreline position. However, the availability of historical data is limited at many coastal sites and so the choice of data source is largely limited to what is available for the site at a given time. Shoreline mapping techniques have become more automated. The frequent changes in technology prevented the emergence of one standard mapping approach. Each data source and associated method have capabilities and shortcomings.
=Historical maps
=
In the event that a study requires the shoreline position from before aerial photographs, or if the location has poor photographic coverage, historical maps provide an alternative. Many errors are associated with early maps and charts. Such errors may be associated with scale,
datum
In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted. ...
changes, distortions from uneven shrinkage, stretching, creases, tears and folds, different
surveying
Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them. A land surveying professional is ca ...
standards, different publication standards and
projection
Projection, projections or projective may refer to:
Physics
* Projection (physics), the action/process of light, heat, or sound reflecting from a surface to another in a different direction
* The display of images by a projector
Optics, graphic ...
errors. The severity of these errors depends on the accuracy of the map and the physical changes that occurred after it was made. The oldest reliable source of shoreline data in the United States dates is the
U.S Coast and Geodetic Survey/
National Ocean Service
The National Ocean Service (NOS) is an office within the U.S. Department of Commerce National Oceanic and Atmospheric Administration (NOAA). It is responsible for preserving and enhancing the nation's coastal resources and ecosystems along the of ...
T-sheets and dates to the early-to-mid-19th century. In the United Kingdom, many pre-1750 maps and charts were deemed to be inaccurate. The founding of the
Ordnance Survey
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, logo = Ordnance Survey 2015 Logo.svg
, logo_width = 240px
, logo_caption =
, seal =
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in 1791 improved mapping accuracy.
=Aerial photographs
=
Aerial photographs began to be used in the 1920s to provide
topographical
Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps.
Topography is a field of geoscience and planetary sci ...
data. They provide a good
database
In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases sp ...
for compilation of shoreline change maps. Aerial photographs are the most commonly used data source because many coastal areas have extensive aerial photo coverage.Aerial photographs generally provide good spatial coverage. However, temporal coverage is site specific. The interpretation of shoreline position is subjective given the dynamic nature of the coastal environment. This combined with various distortions inherent in aerial photographs can lead to
significant error levels. The minimisation of further errors is discussed below.
Object space displacements
![Displacement1](https://upload.wikimedia.org/wikipedia/commons/f/ff/Displacement1.jpg)
Conditions outside of the camera can cause objects in an image to appear displaced from their true ground position. Such conditions may include ground relief, camera
tilt
Tilt may refer to:
Music
* Tilt (American band), a punk rock group, formed in 1992
* Tilt (British band), an electronic music group, formed in 1993
* Tilt (Polish band), a rock band, formed in 1979
Albums
* ''Tilt'' (Cozy Powell album), 1981
* ...
and
atmospheric refraction
Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. This refraction is due to the velocity of light t ...
.
Relief displacement is prominent when photographing a variety of
elevation
The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Vert ...
s. This situation causes objects above sea level to be displaced outward from the centre of the photograph and objects below ground level to be displaced toward the centre of the image (Figure 2). The severity of the displacement is negatively associated with decreases in flight altitude and as
radial distance
In mathematics, the polar coordinate system is a two-dimensional coordinate system in which each point on a plane is determined by a distance from a reference point and an angle from a reference direction. The reference point (analogous to the ...
from the centre of the photograph increases. This distortion can be minimised by photographing multiple
swaths and creating a
mosaic
A mosaic is a pattern or image made of small regular or irregular pieces of colored stone, glass or ceramic, held in place by plaster/mortar, and covering a surface. Mosaics are often used as floor and wall decoration, and were particularly pop ...
of the images. This technique creates a focus for the centre of each photograph where distortion is minimised. This error is not common in shoreline mapping as the relief is fairly constant. It is however important to consider when mapping cliffs.
Ideally aerial photographs are taken so the
optical axis
An optical axis is a line along which there is some degree of rotational symmetry in an optical system such as a camera lens, microscope or telescopic sight.
The optical axis is an imaginary line that defines the path along which light propagat ...
of the camera is perfectly
perpendicular
In elementary geometry, two geometric objects are perpendicular if they intersect at a right angle (90 degrees or π/2 radians). The condition of perpendicularity may be represented graphically using the ''perpendicular symbol'', ⟂. It can ...
to the ground surface, thereby creating a
vertical
Vertical is a geometric term of location which may refer to:
* Vertical direction, the direction aligned with the direction of the force of gravity, up or down
* Vertical (angles), a pair of angles opposite each other, formed by two intersecting s ...
photograph. Unfortunately this is often not the case and virtually all aerial photographs experience tilt up to 3°. In this situation the scale of the image is larger on the upward side of the tilt axis and smaller on the downward side. Many coastal researchers do not consider this in their work.
Radial lens distortion
Lens
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
distortion varies as a function of radial distance from the iso-centre of the photograph meaning that the centre of the image is relatively distortion free, but as the
angle
In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''Side (plane geometry), sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), vertex'' of the angle.
Angles formed by two ...
of view increases distortion. This is a significant source of error in earlier aerial photography. Such a distortion is impossible to correct for without knowing the details of the lens used to capture the image. Overlapping images can be used to resolve errors.
Shoreline delineation
The dynamic nature of coasts compromises shoreline mapping. This uncertainty arises because at any given time the position of the shoreline is influenced by the immediate tidal effects and a variety of long-term effects such as relative sea-level rise and along
shore
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 ...
littoral
The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal areas ...
sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...
movement. This affects the accuracy of computed historic shoreline position and predictions. HWL is most commonly used as a shoreline indicator. Many errors are associated with using the wet/dry line as a proxy for the HWL and shoreline. The errors of largest concern are the short-term migration of the wet/dry line, interpretation of the wet/dry line on a photograph and measurement of the interpreted line position. Systematic errors such as the migration of the wet/dry line arise from tidal and
seasonal
A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's tilted orbit around the Sun. In temperate and po ...
changes.
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 ...
may cause the wet/dry line to migrate. Field investigations have shown that these changes can be minimised by using only summertime data.; Furthermore, the error bar can be significantly reduced by using the longest record of reliable data to calculate erosion rates. Errors may arise due to the difficulty of measuring a single line on a photograph. For example, where the pen line is 0.13 mm thick this translates to an error of ±2.6 m on a 1:20000 scale photograph.
=Beach profiling surveys
=
Beach profiling surveys are typically repeated at regular intervals along the coast in order to measure short-term (daily to annual) variations in shoreline position and beach volume. Beach profiling is a very accurate source of information. However, measurements are generally subject to the limitations of conventional surveying techniques. Shoreline data derived from beach profiling is often spatially and temporally limited due to the high cost associated with that labour-intensive activity. Shorelines are generally derived by
interpolating from a series of discrete beach profiles. The distance between the profiles is usually quite large, limiting the accuracy of the interpolating. Survey data is limited to smaller lengths of shoreline generally less than ten kilometres. Beach profiling data is commonly available in from regional councils in New Zealand.
=Remote sensing
=
A range of airborne,
satellite
A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...
and land based
remote sensing
Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object, in contrast to in situ or on-site observation. The term is applied especially to acquiring information about Earth ...
techniques can provide additional, mappable data. Remotely sensed data sources include:
*
Multispectral
Multispectral imaging captures image data within specific wavelength ranges across the electromagnetic spectrum. The wavelengths may be separated by filters or detected with the use of instruments that are sensitive to particular wavelengths, ...
and
hyperspectral
Hyperspectral imaging collects and processes information from across the electromagnetic spectrum. The goal of hyperspectral imaging is to obtain the spectrum for each pixel in the image of a scene, with the purpose of finding objects, identifyi ...
imaging
*
Microwave
Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ran ...
sensors
*
Global positioning system
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite sy ...
(GPS)
*
Airborne light detection and ranging technology (LIDAR)
Remote sensing techniques can be cost effective, reduce manual error and reduce the subjectivity of conventional field techniques. Remote sensing is a relatively new concept, limiting extensive historical observations. Coastal morphology observations must be quantified by coupling remotely sensed data with other sources of information detailing historic shoreline position from archived sources.
=Video analysis
=
Video
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) syste ...
analysis provides quantitative, cost-effective, continuous and long-term monitoring beaches. The advancement of coastal video systems in the twenty-first century enabled the extraction of large amounts of geophysical data from images. The data describes coastal morphology, surface currents and wave parameters. The main advantage of video analysis lies in the ability to reliably quantify these parameters with high resolution space and time coverage. This highlights their potential as an effective coastal monitoring system and an aid to coastal zone management. Interesting case studies have been carried out using video analysis. One group used a video-based ARGUS coastal imaging system
to monitor and quantify the regional-scale coastal response to sand nourishment and construction of the world-first
Gold Coast
Gold Coast may refer to:
Places Africa
* Gold Coast (region), in West Africa, which was made up of the following colonies, before being established as the independent nation of Ghana:
** Portuguese Gold Coast (Portuguese, 1482–1642)
** Dutch G ...
artificial surfing
reef
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock out ...
in Australia. Another assessed the added value of high
resolution
Resolution(s) may refer to:
Common meanings
* Resolution (debate), the statement which is debated in policy debate
* Resolution (law), a written motion adopted by a deliberative body
* New Year's resolution, a commitment that an individual mak ...
video observations for short-term predictions of near shore hydrodynamic and morphological processes, at temporal scales of meters to kilometres and days to seasons.
Video analysis gives coastal zone managers the opportunity to obtain
bathymetry
Bathymetry (; ) is the study of underwater depth of ocean floors (''seabed topography''), lake floors, or river floors. In other words, bathymetry is the underwater equivalent to hypsometry or topography. The first recorded evidence of water de ...
. It can be used to obtain inter-tidal topographies and sub-tidal bathymetries and measure coastal zone resilience
Video-based depth estimations were applied in micro/meso tidal environments at DUCK, NC and highly energetic wave climates with a macro tidal regime at Porthtowan in the United Kingdom. The latter showed the application of video-based depth estimations during extreme storms.
See also
*
Beach erosion and accretion
**
Beach evolution
Beach evolution occurs at the shoreline where sea, lake or river water is eroding the land. Beaches exist where sand accumulated from centuries-old, recurrent processes that erode rocky and sedimentary material into sand deposits. River deltas dep ...
**
Beach nourishment
Beach nourishment (also referred to as beach renourishment, beach replenishment, or sand replenishment) describes a process by which sediment, usually sand, lost through longshore drift or erosion is replaced from other sources. A wider beach ca ...
**
Modern recession of beaches
Beach evolution occurs at the shoreline where sea, lake or river water is eroding the land. Beaches exist where sand accumulated from centuries-old, recurrent processes that erode rocky and sedimentary material into sand deposits. River deltas dep ...
**
Raised beach
A raised beach, coastal terrace,Pinter, N (2010): 'Coastal Terraces, Sealevel, and Active Tectonics' (educational exercise), from 2/04/2011/ref> or perched coastline is a relatively flat, horizontal or gently inclined surface of marine origin,P ...
*
Integrated coastal zone management
Integrated coastal zone management (ICZM), integrated coastal management (ICM), or integrated coastal planning is a coastal management process for the management of the coast using an integrated approach, regarding all aspects of the coastal zone ...
**
Coastal and oceanic landforms
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 n ...
**
Coastal development hazards A coastal development hazard is something that affects the natural environment by human activities and products. As coasts become more developed, the vulnerability component of the equation increases as there is more value at risk to the hazard. The ...
**
Coastal erosion
Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms. The landward ...
**
Coastal geography
Coastal geography is the study of the constantly changing region between the ocean and the land, incorporating both the physical geography (i.e. coastal geomorphology, climatology and oceanography) and the human geography (sociology and history) ...
***
Cuspate foreland
Cuspate forelands, also known as cuspate barriers or nesses in Britain, are geographical features found on coastlines and lakeshores that are created primarily by longshore drift.Craig-Smith, S. J., Cuspate Forelands. In: M. L. Schwartz, ed. 2005. ...
***
Detention basin
A detention basin or retarding basin is an excavated area installed on, or adjacent to, tributaries of rivers, streams, lakes or bays to protect against flooding and, in some cases, downstream erosion by storing water for a limited period of time ...
**
Coastal engineering
Coastal engineering is a branch of civil engineering concerned with the specific demands posed by constructing at or near the coast, as well as the development of the coast itself.
The hydrodynamic impact of especially waves, tides, storm surges ...
***
Hard engineering
Hard engineering involves the construction of hydraulic structures to protect coasts from erosion. Such structures include seawalls, gabions, breakwaters, groynes and tetrapods.
Effects
Hard engineering can cause unintended environmental consequen ...
****
Accropode
****
Xbloc
***
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 ...
**
Coastal morphodynamics
Coastal morphodynamics (i.e. the dynamics of beach morphology) refers to the study of the interaction and adjustment of the seafloor topography and fluid hydrodynamic processes, seafloor morphologies and sequences of change dynamics involving th ...
**
Coastal and Estuarine Research Federation
The Coastal and Estuarine Research Federation (CERF) is a private, nonprofit organization that was created in 1971. At that time, the members of two regionally based organizations, the Atlantic Estuarine Research Society (AERS) and the New England ...
(CERF)
**
Human impacts on coasts
**
Sea level rise
Globally, sea levels are rising due to human-caused climate change. Between 1901 and 2018, the globally averaged sea level rose by , or 1–2 mm per year on average.IPCC, 2019Summary for Policymakers InIPCC Special Report on the Ocean and Cry ...
**
Mangrove restoration
Mangrove restoration is the regeneration of mangrove forest ecosystems in areas where they have previously existed. The practice of mangrove restoration is grounded in the discipline of restoration ecology, which aims to “ ssistthe recovery of ...
**
Natural hazard
A natural hazard is a natural phenomenon that might have a negative effect on humans and other animals, or the environment. Natural hazard events can be classified into two broad categories: geophysical and biological.
An example of the distinct ...
**
Restoration of saltwater swamps
**
Restoration of salt marshes
**
List of countries by length of coastline
This article contains a list of countries by length of coastline, in kilometers. A coastline of zero indicates that the country is landlocked.
Overview
The coastline paradox states that a coastline does not have a well-defined length. Measureme ...
*
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 ...
**
Bioerosion
Bioerosion describes the breakdown of hard ocean substrates – and less often terrestrial substrates – by living organisms. Marine bioerosion can be caused by mollusks, polychaete worms, phoronids, sponges, crustaceans, echinoids, and ...
**
Blowhole
**
Natural arch
A natural arch, natural bridge, or (less commonly) rock arch is a natural landform where an arch has formed with an opening underneath. Natural arches commonly form where inland cliffs, coastal cliffs, fins or stacks are subject to erosion f ...
**
Wave-cut platform
A wave-cut platform, shore platform, coastal bench, or wave-cut cliff is the narrow flat area often found at the base of a sea cliff or along the shoreline of a lake, bay, or sea that was created by erosion. Wave-cut platforms are often most obv ...
*
Longshore drift
Longshore drift from longshore current is a geological process that consists of the transportation of sediments (clay, silt, pebbles, sand, shingle) along a coast parallel to the shoreline, which is dependent on the angle incoming wave direction ...
**
Deposition (sediment)
Deposition is the geological process in which sediments, soil and rocks are added to a landform or landmass. Wind, ice, water, and gravity transport previously weathered surface material, which, at the loss of enough kinetic energy in the fluid, ...
**
Coastal sediment supply
Coastal sediment supply is the transport of sediment to the beach environment by both fluvial and aeolian transport. While aeolian transport plays a role in the overall sedimentary budget for the coastal environment, it is paled in comparison to ...
**
Longshore transport
Longshore drift from longshore current is a geological process that consists of the transportation of sediments (clay, silt, pebbles, sand, shingle) along a coast parallel to the shoreline, which is dependent on the angle incoming wave direction ...
**
Sand dune stabilization Sand dune stabilization is a coastal management practice designed to prevent erosion of sand dunes. Sand dunes are common features of shoreline and desert environments. Dunes provide habitat for highly specialized plants and animals, including rar ...
**
Submersion
References
Citations
Sources
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Further reading
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External links
Coastal WikiDeltaworks Online - Coastal Defenses in the NetherlandsSafecoastKnowledge exchange on
coastal flooding
Coastal flooding normally occurs when dry and low-lying land is submerged by seawater. The range of a coastal flooding is a result of the elevation of floodwater that penetrates the inland which is controlled by the topography of the coastal land ...
and climate change in the North Sea region
Encora Coastal WikiSocial & Economic Benefits of Coastal Resource Managementfrom "NOAA Socioeconomics" website initiative
Coastal Resources Center, University of Rhode Island
;Videos:
*
;Images:
*'What is Remote Sensing',
mage
Mage most commonly refers to:
* Mage (paranormal) or magician, a practitioner of magic derived from supernatural or occult sources
* Mage (fantasy) or magician, a type of character in mythology, folklore, and fiction
*Mage, a character class in s ...
n.d. Retrieved 1 April 2010 fro
{{DEFAULTSORT:Coastal Management
Coastal construction
Coastal engineering
Coastal geography
Civil engineering