An example of a modern seawall in Ventnor on the Isle of Wight

People socializing and walking at the Malecón, Havana

A seawall (also written as sea wall) is a form of coastal defence 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 and leisure activities from the action of tides and waves.^[1] As a seawall is a static feature it will conflict with the dynamic nature of the coast and impede the exchange of sediment between land and sea.^[2]

The coast is generally a high-energy, dynamic environment with spatial variations occurring over a wide range of temporal scales.^[3] The shoreline is part of the coastal interface which is exposed to a wide range of erosional processes arising from fluvial, aoelian and terrestrial sources, meaning that a combination of denudational processes will work against a seawall.^[4] Given the natural forces to which seawalls are constantly subjected, maintenance (and eventually replacement) is an ongoing requirement if they are to provide an effective long term solution.

The many types of seawall in use today reflects both the varying physical forces they are designed to withstand, and location specific aspects, such as: local climate, coastal position, wave regime, and value of landform. Seawalls are classified as a hard engineering shore based structure used to provide protection and to lessen coastal erosion. However, a range of environmental problems and issues may arise from the construction of a seawall, including disrupting sediment movement and transport patterns, which are discussed in more detail below.^[5] Combined with a high construction cost, this has led to an increasing use of other soft engineering coastal management options such as beach replenishment.

Seawalls may be constructed from a variety of materials, most commonly: reinforced concrete, boulders, steel, or gabions. Additional seawall construction materials may include: vinyl, wood, aluminium, fibreglass composite, and with large biodegrable sandbags made of jute and coir.^[6] In the UK, sea wall also refers to an earthen bank used to create a polder, or a dike.

Design principles and types[link]

A seawall works by reflecting incident wave energy back into the sea, therefore reducing the energy and erosion which the coastline would otherwise be subjected to.^[7] In addition to their unsightly visual appearance, two specific weaknesses of seawalls exist. Firstly, wave reflection induced by the wall may result in scour and subsequent lowering of the sand level of the fronting beach.^[8] Secondly, seawalls may accelerate erosion of the adjacent, unprotected coastal properties because they affect the littoral drift process.^[9] Fundamentally, a cost-benefit approach is an effective way to determine whether a seawall is appropriate or not and if the negative effects are worth the protection of threatened property.

The design and type of a seawall varies depending on unique aspects specific to each location, and the erosional processes and environment which they are placed in.^[10] There are three main types of seawalls: vertical; curved or stepped; and mounds. These are described more comprehensively below and summarised with positive and negative aspects and global examples within Table 1.

Vertical seawalls

are built in particularly exposed situations. These reflect wave energy and, under storm conditions, standing waves (clapotis) will develop. In some cases piles are placed in front of the wall to lessen wave energy slightly.

Curved seawalls

are designed to enable waves to break to dissipate wave energy and to repel waves back to the sea. The curve can also prevent the wave overtopping the wall and provides additional protection for the toe of the wall.

Mound-type structures

(revetments, riprap) are used in less demanding settings where lower energy erosional processes operate. The least exposed sites involve the lowest-cost bulkheads and revetments of sand bags or geotextiles. These serve to armour the shore and minimise erosion and may be either watertight or porous, which allows water to filter through after the wave energy has been dissipated.^[11]

^[12]

Furthermore, Figures 1 and 2 below provide a visual illustration of the structure and design of these three types of seawall.

Figure one: Vertical and curved-type seawalls. Figure two: Mound-type seawall.

Source: University of Barcelona (2007) ^[13]

History[link]

The examples and perspective in this section may not represent a worldwide view of the subject. Please improve this article and discuss the issue on the talk page. (November 2011)

Seawall construction has existed since ancient times. In the 1st century BCE, Romans built a seawall / breakwater at Caesarea Maritima creating an artificial harbor (Sebastos Harbor). The construction used Pozzolana concrete which hardens in contact with sea water. Barges were constructed and filled with the concrete. They were floated into position and sunk. The resulting harbor / breakwater / sea wall is still in existence today - more than 2000 years later.

More recently, sea walls were constructed in 1623 in Canvey Island, UK, when great floods of the Thames estuary occurred, prompting the construction of protection for further events in this flood prone area (Council of Europe, 1999).^[14] Since then, seawall design has become more complex and intricate in response to an improvement in materials, technology and an understanding of how coastal processes operate. This section will outline some key case studies of seawalls in chronological order and describe how they have performed in response to tsunami or ongoing natural processes and how effective they were in these situations. Analysing the successes and shortcomings of seawalls during severe natural events allows their weaknesses to be exposed, and areas become visible for future improvement.

Pondicherry[link]

On December 26, 2004, towering waves of the 2004 Indian Ocean earthquake tsunami crashed against India's south-eastern coastline killing thousands. However, the former French colonial enclave of Pondicherry (now Pondicherry) escaped unscathed. This was primarily due to French engineers who had constructed (and maintained) a massive stone seawall during the time which the city was a French colony. This 300 year old seawall effectively kept Pondicherry's historic centre dry even though tsunami waves drove water 24 feet above the normal high-tide mark.

The barrier was initially completed in 1735 and over the years, the French continued to fortify the wall, piling huge boulders along its 1.25 mile (2 km) coastline to stop erosion from the waves pounding the harbour. At its highest, the barrier running along the water's edge reaches about 27 feet above sea level. The boulders, some weighing up to a ton, are weathered black and brown. The sea wall is inspected every year and whenever gaps appear or the stones sink into the sand, the government adds more boulders to keep it strong (Allsop, 2002).^[15]

The Union Territory of Pondicherry recorded some 600 deaths from the huge tsunami waves that struck India's coast after the mammoth underwater earthquake (which measured 9.0 on the moment magnitude scale) off Indonesia, but most of those killed were fishermen who lived in villages beyond the artificial barrier which reinforces the effectiveness of seawalls.

Vancouver Seawall[link]

The Vancouver Seawall is a stone seawall constructed around the perimeter of Stanley Park in Vancouver. The seawall was constructed initially as waves created by ships passing through the First Narrows were eroding the area between Prospect Point and Brockton Point. The Vancouver Seawall also exemplifies how seawalls can be utilised and valued for recreational activities and coastal sightseeing. A pedestrian, cycling and roller blading pathway exists on the seawall and has been extended far outside the parameters of Stanley Park. Construction of the seawall began in 1914, and since then this pathway has become one of the most used features of the park by both locals and tourists and now extends 22 km in total (Belyea & Ross, 1992).^[16] The construction of the seawall also provided employment for relief workers during the Great Depression and seamen from the HMCS Discovery on Deadman's Island who were facing punishment detail in the 1950s (Steele, 1985).^[17]

Overall, the Vancouver Seawall is a prime example of how seawalls can simultaneously provide shoreline protection and a source of recreation which enhances human enjoyment of the coastal environment. It also illustrates that although shoreline erosion is a natural process, human activities, interactions with the coast and poorly planned shoreline development projects can accelerate natural erosion rates.

Japan[link]

At least 43 per cent of Japan’s 35,500 kilometre coastline is lined with concrete seawalls or other structures designed to protect the country against high waves, typhoons or even tsunamis (New York Times, 2011).^[18] When a Tsunami struck in 2011 following a magnitude 9 offshore earthquake, the seawalls in most areas were overwhelmed. In Kamaishi, 4-metre waves surmounted the seawall —the world’s largest, erected a few years ago in the city’s harbour at a depth of 63 metres, a length of 2 kilometres and a cost of $1.5 billion — and eventually submerged the city centre (Musubi, 2011).^[19]

The risks of dependence on seawalls was most evident in the crisis at the Daiichi and Daini nuclear power plants, both located along the coast close to the earthquake zone, as the tsunami washed over walls that were supposed to protect the plants. Arguably, the additional defence provided by the seawalls presented an extra margin of time for citizens to evacuate and also stopped some of the full force of energy which would have caused the wave to climb higher in the backs of coastal valleys. In contrast, the seawalls also acted in a negative way to trap water and delay its retreat.

The failure of the world's largest seawall, which cost $1.5 billion to construct, shows that building stronger sea walls to protect larger areas would have been too costly to be effective. In the case of the ongoing crisis at the nuclear power plants, higher and stronger sea walls should have been built if power plants were to be built at that site. Fundamentally, the devastation in coastal areas and a final death toll predicted to exceed 10,000 could push Japan to redesign its seawalls or consider more effective alternative methods of coastal protection for extreme events. Such hardened coastlines can also provide a false sense of security to property owners and local residents as evident in this situation (Msubi, 2011).^[20]

Advanced numerical study[link]

3D Numerical Simulation - MEDUS 2009

3D Numerical Simulation - MEDUS 2009

3D Numerical Simulation - MEDUS 2009

The Maritime Engineering Division at the University of Salerno (MEDUS) developed a new procedure to study, with a more detailed and innovative approach, the interactions between maritime breakwaters (submerged or emerged) and the waves, by an integrated use of CAD and CFD software (MEDUS, 2011).^[21]

In the numerical simulations the filtration motion of the fluid within the interstices, which normally exist in a breakwater, is estimated by integrating the RANS equations, coupled with a RNG turbulence model, inside the voids, not using a classical equations for porous media. The breakwaters were modeled, as it happens in the full size construction or in physical laboratory test, by overlapping three-dimensional elements and the numerical grid was thickened in such a way to have some computational nodes along the flow paths among the breakwater’s blocks.^[22]

Future research[link]

Sea level rise[link]

Sea level rise creates an issue for seawalls worldwide as it raises both the mean normal water level and the height of waves during extreme weather events, which the current seawall heights may be unable to cope with (Allan et al. 1999).^[23] The International Panel on Climate Change (IPCC) (1997)^[24] suggested that sea level rise over the next 50 – 100 years will accelerate with a projected increase in global mean sea level of +18 cm by 2050 AD. This data is reinforced by Hannah (1990)^[25] who calculated similar statistics including a rise of between +16-19.3 cm throughout 1900–1988. This problem could be overcome by further modelling and determining the extension of height and reinforcement of current seawalls which needs to occur for safety to be ensured in both situations.

Extreme events[link]

Extreme events also pose a problem as it is not easy for people to predict or imagine the strength of hurricane or storm induced waves compared to normal, expected wave patterns. An extreme event can dissipate hundreds of times more energy than everyday waves, and calculating structures which will stand the force of coastal storms is difficult and, often the outcome can become unaffordable. For example, Omaha Beach seawall in New Zealand was designed to prevent erosion from everyday waves only, and when a storm in 1976 carved out 10m behind the existing seawall the whole structure was destroyed (GeoResources, 2001).^[26]

Other limitations[link]

Some further limitations include: lack of long term trend data of seawall effects due to a relatively short duration of data records; modelling limitations and comparisons of different projects and their effects being invalid or unequal due to different beach types; materials; currents; and environments (Christchurch City Council, 2009).^[27]

Efficacy and trade-offs[link]

In conclusion, a cost benefit approach is an effective way to determine whether a seawall is appropriate and if the benefits are worth the expense. Besides controlling erosion, consideration must be given to the effects of hardening a shoreline upon natural coastal ecosystems and human property or activities. Overall, a holistic approach to planning is ideal. It is important to remember that a seawall is a static feature, it will conflict with the dynamic nature of the coast and impede the exchange of sediment between land and sea. Table 2 summarises the overall positive and negative effects of seawalls which is useful when comparing their effectiveness to other coastal management options such as beach nourishment.

After Short (1999).^[28]

Fundamentally, seawalls are generally a successful way to control coastal erosion but only if they are constructed well and out of materials which can withstand the force of ongoing wave energy. Likewise, a thorough understanding of coastal processes and location specific morphodynamics is imperative to enhance the successful implementation and lifespan of a seawall. Seawalls are highly useful as they are more long term than other soft engineering options and they can simultaneously provide recreation opportunities and protection from not everyday erosion but that of extreme events. Analysing the successes and shortcomings of seawalls during severe natural events allows their weaknesses to be exposed and areas become visible for future improvement and reassessment.

See also[link]

References[link]

External links[link]

Wikimedia Commons has media related to: Seawalls

Look up seawall in Wiktionary, the free dictionary.

• Channel Coastal Observatory - Seawalls
• Constructing a new sea wall and defences at Lyme Regis in Dorset
• Seawalls and defences on the Isle of Wight
• MEDUS (Maritime Engineering Division University Salerno)
• "Japan may rethink seawalls after tsunami", New York Times, March 14, 2011

v t e Coastal management Management Coastal management Accretion Coastal engineering Integrated coastal zone management Managed retreat Submersion Hard engineering A-jack Accropode Akmon Artificial reef Breachway Breakwater Cliff stabilization Dolos Flood wall Floodgate Gabion Groyne Levee Hard engineering Honeycomb sea wall Hudson's equation Revetment Riprap Seawall Tetrapod Training wall Xbloc Soft engineering Beach nourishment Beach drainage Sand dune stabilization Soft engineering Soft shore remediation Related topics Beach evolution Coastal erosion Land reclamation Longshore transport Modern recession of beaches

Simon Stephens
Born	1971
Occupation	Playwright
Nationality	British
Literature portal

Simon Stephens (born 1971) is an award winning English playwright. Having taught on the Young Writers' Programme at the Royal Court Theatre for many years he is now an Artistic Associate at the Lyric Hammersmith. His writing is characterised as part of in in-yer-face theatre generation and is not only widely performed in the UK but throughout Europe with several of his plays being premiered abroad. Along with Dennis Kelly he is one of the most performed English writers in Germany.

Early Life[link]

Originally from Stockport, Greater Manchester, he studied and graduated from the University of York.

He was a member of Scottish art punk band Country Teasers.

He lives in London with his wife and children.

Plays[link]

• Three Kingdoms (2011) premiered at Theatre NO99 in Tallinn, Estonia, directed by Sebastian Nübling^[1], English premiere at the Lyric Theatre (2012)^[2] | German premiere at the Munich Kammerspiele (2011)
• I Am The Wind (2011) translation of the Jon Fosse play premiered at the Young Vic, directed by Patrice Chéreau^[3]
• Wastwater (2011) premiered at the Royal Court Theatre, directed by Katie Mitchell^[4]
• The Trial of Ubu (2010) premiered at the Toneelgroep in Amsterdam, (2012) English premiere at the Hampstead Theatre, directed by Katie Mitchell^[5]
• 'T5 (2010) premiered at the Traverse Theatre as part of Traverse Live!, directed by Dominic Hill^[6]
• A Thousand Stars Explode in the Sky (2010) written with David Eldridge and Robert Holman premiered at the The Lyric, directed by Sean Holmes^[7]
• Marine Parade (2010) with music by Mark Eitzel premiered at the Brighton Festival directed by Jo McInnes^[8]
• Punk Rock (2009) premiered at the Royal Exchange Theatre, directed by Sarah Frankcom^[9]
• Sea Wall (2008) premiered in the Broken Space Season at Bush Theatre, directed by George Perrin^[10]
• Pornography (2007) premiered at the Traverse Theatre directed by Sean Holmes^[11]
• Harper Regan (2007) premiered at the National Theatre, directed by Marianne Elliott^[12]
• Motortown (2006) premiered at the Royal Court Theatre, directed by Ramin Gray^[13]
• On the Shore of the Wide World (2005) premiered at the Royal Exchange Theatre, directed by Sarah Frankcom^[14]
• Country Music (2004) premiered at the Royal Court Theatre, directed by Gordon Anderson^[15]
• Christmas (2004) premiered at the Bush Theatre, directed by Joanne McInnes^[16]
• One Minute (2003) premiered at the ATC, directed by Gordon Anderson^[17]
• Port (2002) premiered at the Royal Exchange, directed by Marianne Elliott^[18]
• Herons (2001) premiered at the Royal Court Theatre, directed by Simon Usher^[19]
• Bluebird (1998) premiered at the Royal Court Theatre, directed by Gordon Anderson^[20]

Awards[link]

• Punk Rock nominated TMA Awards Best New Play 2010
  nominated Evening Standard Award Best New Play 2010
• Pornography won Critics' Awards for Theatre in Scotland Best New Play 2008
• On the Shore of The Wide World won Olivier Award Best New Play 2005
• Port won the Pearson Award Best New Play 2001

References[link]

Ricardo Villalobos
Background information
Birth name	Ricardo Villalobos
Also known as	Bispeed Black, Richard Wolfsdorf, Termiten
Born	1970 (age 41–42)
Origin	Santiago de Chile, Chile
Genres	Microhouse Minimal Techno Techno
Occupations	Disc jockey Record producer
Years active	1993–present
Labels	Sei Es Drum Perlon Playhouse Frisbee Tracks Sister Phunk Lo-Fi Stereo
Associated acts	Bajo Tierra, Chirurgie Boutique, Gucci, Hombre Ojo, R & R, Ric Y Martin, Ricardo vs. Jay, Sense Club
Website	ongaku.de

Ricardo Villalobos (born 1970) is a Chilean-German electronic music producer and DJ. He is well known for his work in the minimal techno and microhouse genres, and is one of the most significant figures in today's minimal techno scene.

Villalobos was born in Santiago, Chile in 1970.^[1] In 1973^[1] he moved to Germany with his family to escape the dictatorship of Augusto Pinochet,^[2] who had seized power that year.

When Ricardo was around 10 or 11 he started to play conga and bongos. Though he loved music, he could never see himself as a musician.^{[citation needed]} He began making electronic music in the late 80s. From a very young age he has been a big fan of Depeche Mode, even following their tours around Europe to listen to them.

Villalobos began to play his music at parties while he was studying at university, but this was only for his own enjoyment. He started a label, Placid Flavour, in 1993 but this was unsuccessful. His first record was released on the German Playhouse label in 1994 and he began DJing as a professional in 1998.

At the end of 2008 and 2010, he came 1st in Resident Advisor's Top 100 DJs of the year.^[3]

Discography[link]

Albums[link]

• Alcachofa (2003)
• Thé Au Harem D'Archimède (2004)
• Fizheuer Zieheuer (2006)
• Salvador (2006)
• Fabric 36 (2007)
• Sei Es Drum (2007)
• Vasco (2008)
• Re:ECM with Max Loderbauer (2011)

Singles[link]

• Sinus Poetry EP (1993)
• The Contempt (1995)
• Heike (1995)
• N-DRA (1996)
• Salvador (1998)
• 808 the Bassqueen (1999)
• Frank Mueller Melodram (1999)
• Pino Jet Explosion (1999)
• Ibiza99 (2000)
• Luna (2000)
• Que Belle Epoque (2000)
• Tomorrov Cocktail / Ananas (2000)
• Bredow / Damm 3 (2001)
• Halma (2002)
• 808 The Bass Queen / Filtadelic (2003)
• The Contempt (2004)
• Achso (2005)
• Chromosul (2005)
• For Disco Only 2 (2005)
• Que Belle Epoque 2006 (2006)
• Heike (2006)
• Seive / Jimis (2006)
• Unflug (2006)
• What You Say Is More Than I Can Say (2006)
• What's Wrong My Friends? (2006)
• Enfants (2008)
• Vasco EP Part 1 (2008)
• Vasco EP Part 2 (2008)
• Peculiar / Zuge (2010)

Mix albums[link]

• Love Family Trax (2002)
• In the Mix: Taka Taka (2003)
• Green & Blue (2005)
• Fabric 36 (2007)

Remixes[link]

• 1996 Der Dritte Raum – "Trommelmaschine"
• 1997 Heiko Laux & Johannes Heil – "No Pain No Gain"
• 1997 Sieg Über Die Sonne – "Mogul"
• 1999 Vermittelnde-Elemente – "Modedom"
• 2000 The Horrorist – "One Night in NYC"
• 2000 Heiko Laux – "Moved"
• 2000 Pascal F.E.O.S. – "Are U Tranquilized"
• 2001 Auch – "Tomorrow Goodbye"
• 2001 Two Lone Swordsmen – "Bunker"
• 2002 Auch – "Pick-Up"
• 2002 Thomas Dolby – "One of our Submarines"
• 2002 Jeff Samuel – "Vew"
• 2002 Tony Senghore – "Where Is the Love?"
• 2002 Señor Coconut And His Orchestra – "Electro Latino"
• 2002 Sieg Über Die Sonne – "You'll Never Come Back"
• 2003 Hell – "Listen to the Hiss"
• 2003 Monne Automne – "El Salvador"
• 2003 Spektrum – "Freakbox"
• 2003 Sven Väth – "Cala Llonga"
• 2004 Alter Ego – "Daktari"
• 2004 DJ Minx – "A Walk in the Park"
• 2004 Lopazz – "Migracion"
• 2004 Lucien–N–Luciano – "Alain Brito"
• 2004 Monobox – "Trade"
• 2004 Sieg Über Die Sonne – "Love Is OK"
• 2005 2raumwohnung – "Wir Sind Die Anderen"
• 2005 The KLF – "What Time Is Love?"
• 2005 Sieg Über Die Sonne – "Cleaning Windows"
• 2005 Vegetable Orchestra – "Atavismus"
• 2005 Das Racist - "The Bing Bong Chong-a-Long"
• 2006 Depeche Mode – "The Sinner in Me"
• 2006 Rhythm & Sound with Ras Donovan & Ras Perez – "Let We Go"
• 2006 Señor Coconut And His Orchestra – "Behind the Mask"
• 2007 Beck – "Cellphone's Dead"
• 2007 Ffwd – "Consequences"
• 2007 Innersphere – "Phunk"
• 2007 Plastikman – "Snark"
• 2007 Shackleton – "Blood on My Hands"
• 2008 Sun Electric – "Toninas"
• 2008 Slap - "Eden Now"
• 2010 NDF - "Since We Last Met"
• 2010 DJ Sneak - "Delta Trippin"
• 2011 Energy 52 - "Café Del Mar"

References[link]

External links[link]

• Biography at The DJ List
• Ricardo Villalobos discography at Discogs
• Ricardo Villalobos: Sound brotherhood Interview (2009) at Resident Advisor
• Interview (2004)