Bego, France
Alice Choupeaux Research booklet 1/4 Spring 2017
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CITAstudio - Centre for IT and Architecture The Royal Danish Academy of Fine Arts
Bego, France
Content
Content Bego, France Climate & vegetation Buildings & infrastructures Chalenges & action plans Dune Dunes dynamic Dunes’ composition Plants of the dunes Animals of the dunes Insects of the dunes Bunkers Construction Current knowlegde Flora & Fauna of the dunes as part of the dunes Materials of the site Site layers History layer Circulation layer Flora layer
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Bego, France
Bego, France
Bego, France The coastal dunes and beaches from Gâvres to Plouharnel are part of the french Armor morbihannais landscapes. It is Brittany’s largest dunes area, a unique place contrasting with the surrounding rocky coastal cliffs. The site’s configuration is remarkable. It represents 26 km long of dunes for less than 1 km width. Slightly curved, its coast line allows beautiful views of the site on itself. Climate & vegetation The climate is of the oceanic tempered type. The temperature rarely goes below 0° or raises more than 30°. Rain is abundant thought out the year ( 800 to 900mm of rain per year ). In the dunes themselves, the conditions are harsh due to the nature of the soil : sand. Constantly moving and extremely permeable, it doesn’t keep water and make it difficult for trees to grow. Absence of trees leads to strong sunlight and high wind speeds. Winds bringing seawater increases the salinity of the soil. Clear-cut, the vegetation that succeeded to grow as massifs in the sand developed remarkable qualities to adapt to this climate. Buildings and infrastructures The site represents 2600 ha of preserved and not urbanised land : in contrast with other areas, there isn’t any built sea-front. Buildings are sparsed behind the dunes. The only buildings and infrastructures in the dunes are linked with touristic or military activity: parkings, small roads and bunkers.
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Bego, France
Bego, France
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5 4%
FEBRUARY
MARCH
4% 3% 4%
OCTOBER
NOVEMBER
DECEMBER
7%
SEPTEMBER
AUGUST
JULY
8%
JUNE
9%
MAY
APRIL
2% 3%
JANUARY
30%
22%
9%
5 130 mm
3%
4%
DECEMBER
150 mm 70h
140 mm DECEMBER
NOVEMBER
100h
NOVEMBER
120 mm OCTOBER
155h
OCTOBER
90 mm SEPTEMBER
200h
SEPTEMBER
AUGUST
JULY
JUNE
240h
AUGUST
JULY
JUNE
90 mm MAY
APRIL
MARCH
FEBRUARY
JANUARY
180h
MAY
100 mm
APRIL
MARCH
FEBRUARY
JANUARY
Bego, France Bego, France 11
260h 240h 210h 140h 100h 70h
160 mm
60 mm 70 mm 65 mm 88 mm
Bego, France
Bego, France
Recent protection actions reduced the amount of cars in the site and canalised people on walking paths to avoid trampling and destruction of the vegetation. Hence, the landscape is marked by ganivelles and geotextiles leading to the beaches. This visual vocabulary is largely accepted and now often associated with the environment of the coastal dunes. - A ganivelle is a fence formed by the assembly of wooden latices (often in chestnut wood, 45mm per 13mm). Each lattice is vertical and assembled one another by a string of galvanised iron. The width of the space between each lattice determines the “permeability” of the fence. This device is sufficient to slow down the wind and thus retains flying material as sand. This quality is used for reconstruction or protection of coastal dunes ; their fonction as fence also help to manage walking areas. Challenges and action plans The dunes are a very sensitive biogeomorphic formations; almost half of the flora and fauna of coastal Brittany is found in the dunes, they are important ecological reserves that need and deserve attention and protection. Since 2000, the Gâvre-Plouarnel site is preserved and controlled by a large protection plan called “Opération Grand Site” (english: large site operation).
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Trampling erosion & wind erosion
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Bego, France
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Before
After
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Bego, France
- The protection plan “Operation Grand Site” was created to try and maintain places of large notoriety subject to high frequentation in France. It wants to define and bring forward a collaborative project of restoration, preservation and enhancement of the landscape’s qualities. Ways of dealing with high visitors rate as well as protecting the surrounding nature are suggested. The coastal dunes and beaches from Gâvres to Plouharnel formed a natural landscape protected from mass urbanisation as well as carefully directed in its management in order to preserve its valuable natural resource without excluding the touristic activity. During the summer the population of the area is multiplied by five which has a direct impact on the environment. All the activities are concentrated as much as possible in the towns behind the dunes and any temporary housings such as campings has to follow strict rules about aesthetic harmonisation with the landscape. The project is fully aware of these problematics and will try to bring a solution while questioning the current rules that strictly forbid any construction on the site. These rules are stated due to the current ways of building which are highly destructive and completely erase nature to sit itself. I believe in a more respectful way of building, an architecture that will work with nature and not against it. Light weight,
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Current action against erosion
Bego, France
Bego, France
Branches to slow down the wind and nourish the soil
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Bego, France
flexible, porous, symbiotic and delicate, this architecture could foster growth, protect from undesired erosion while bringing forward the qualities of the site without isolating us from it. The dunes, because of its protected status, its natural movements, its typical nature and its harsh climatic conditions are an ideal site to test and bring forward the qualities of such an architecture. This project will be a study case and experiment to develop this form of architecture that, I believe, should become a more larger construction technique in order to stop fighting against natural phenomenas but work with them.
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Bego, France
Dunes
Dunes [ The dunes are good demonstrators of our ambiguous relationship with nature. Loved for the feeling of freedom they procure, we still want to strictly regularise any activity around them. Mobile by nature, we try everything to fix them in place ; while every storm remind us that nature can’t be controlled.] Britain dunes slowly appeared during the Bronze Age. From the XVII century, the largest dunes area stopped their progression even though some of them are still highly sensitive to erosion. They are littoral dunes. They grow on the edge of low coast where winds and flying sediments produced by longshore drift allows sand aggregation and the growth of local plants its fixation; they are a biogeomorphic. Dunes dynamic The different areas evolve with one another. Three major factors impacts the general dynamic of the dunes : the swell and the currents model the beaches; the wind built the foredune and transport the sand above and beyond the sea line; plants contribute to fix the sand. The major part of the dunes are fixed but the wind and the sea currents influence and change the form of the beaches and foredune from one year to another. During winter the beaches are thinner and the front of the foredune is shaped as a small cliff by the sea due to the storms and
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high and strong tides. During summer the reverse phenomena happens, the beaches get thicker and the foredunes reconstruct themselves due to the action of the swell and calmer weather conditions. This first part of the dunes is particularly unstable and a violent storm is all needed to destroy years of slow sand aggregation. The dunes are also highly sensitive to erosion. - Three different type of erosion happening in the dunes: - Maritim erosion: action from the sea taking away the early dunes - Wind erosion: the wind digs into the sand as soon as the vegetal layer disappears - Anthropic erosion: humains, by trampling, can be the reason for the vegetation to disappear and sand to be moved. Dune’s composition - Foreshore and foredune The foreshore is made out of algae, shells, driftwood and have two principal roles: One is biologic: number of animal and plants find necessary food and nutriment in this area; The second one is physic: it is the first area where sand is retained. In close collaboration with the foreshore appears the foredune where the first plants grow and fix the sand that can accumulate. The pioneer plants from the top of the beach needs to adapt to the hight salinity of the soil as well as the strafe of sand and sea salt. They are often perennial or annual.
Bego, France
Dunes
- Mobile dune or white dune After the foredune, at the top of the beach a “hillock” appears, that moves forwards and backwards depending on winter storms, its the “mobile dune” or “white dune”. The plants belonging to this environment have long roots and stems that forms a natural fence retaining a large amount of sand. This vegetal layer is diverse but sparse, which give to this part the name of “white dune”. The Oyat is a major plant in the “white dune” because of its long roots network that retains the sand and its flexible stem that bends under the strong wind without breaking. - Fixed dune or gray dune When going further in land the wind speed as well as the sand strafe slow down and allow a more dense and diverse plant layer. The mousses and lichens are the base of this layer and gives it its gray color. These species strongly limit any sand movement and fix the dune which doesn’t move as much as the white dune. Almost 1000 ha of gray dune covers the GâvresQuiberon area. It is the larger dune landscape non interrupted by any urbanisation in Brittany.The main and most precious—because rare—plants found in this area are the association of Rosa pimpinellifolia/Coccoloba uvifera, the Omphalodes littoralis and the Helichrysum stoechas. - Humid zones Humid zones have a rich biodiversity. Their biologic and hydrologic roles are very important. The water level varies through out the year which
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Dune’s erosion comparaison - Bunker on top of the first dune 1950
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Dunes
Dune’s erosion comparaison - Bunker in the water 2016
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Dunes before the storm 2010
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Dunes after the storm 2012
Dunes
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Dunes
influences the type of fauna. Many of them are caused by sand quarries. It is the case of the inter-dunes humid depressions of Kerminihy. The phragmites and caladium are used by birds to nest are the free water are great reproduction area for frogs, salamanders and dragonflies. Plants of the dunes As described before the conditions in the dunes are especially hostile; sea spray and sand can offer at its best a poor, dry, salty soil that furthermore is moving. By adapting their physiology and morphology to a life in the dunes, certain special plants succeeded to conquer this unwelcoming environment as well as being a crucial part of its existence. For instance, to resist to sand impacts some plants developed thick leaves often enveloped to protect their vital parts. Finding water is also one of the more difficult challenge in the sand. Plants like the Oyat developed long roots that can reach deeper layers of soil. The tiny, long and fleshy characters of the some leaves to keep water and prevent drying from the wind. Mousses and lichens even goes totally dry and slow down their metabolism during the summer to survive. Many annual plants exist in the dunes, they flourish in summer, spread their seeds and wait for weather conditions to be ideal again.
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Bego, France
Dunes
Animals of the dunes Birds and habits use the dunes as the site to give birth. As sand is easy to dig in habits built their home all around the grey dune. The high plants ( oyats ) are helping the bird to hide away from their predators. Insects of the dunes Most of the inhabitants of the dunes are insects, spiders and other invertebrates. They appreciate heat and dryness. As the plants they also know how to adapt their behaviour and morphology to the harsh conditions of the dune. Many of them live during the night to seek freshness and moisture and hide themselves in leaves, fruits or underground during the hot days of summer. Most of them have a clear color to hide in the sand or escape overheating from the sun. A lot of flying insects move by jumping to prevent being carry by the wind. Some fly species even lost their wings. This adaptation from the flora and fauna is an inspiration for the structure of the project that will be develop in close collaboration with them, taking the climatic and morphologic conditions as a primordial ( if not only ) first design consideration at the scale of the components and cells. Further than just morphology, the plants and animal also adapt their behaviour through the different seasons, a closer study of this phenomena to consider a possible application will be realised.
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Bego, France
Dunes
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Dunes
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Dunes
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Bego, France
Bunkers
Bunkers After the Second World War, the dunes were left with new imbedded grey concrete blocks : the bunkers, parts of an extensive system of coastal defence and fortifications built by Nazi Germany between 1942 and 1944 called the Atlantic Wall (german:Atlantikwall). On the coast from Northern Scandinavia to Southern France, the defence line was built against an anticipated Allied invasion of Nazi-occupied Europe. Ruins of this wall still exist in all the nations where it was built, although most of the fortifications have fallen in the Ocean or have been demolished over the years. On 23 March 1942, Hitler issued Führer Directive No. 40, which called for the creation of the “Atlantic Wall”. Naval and submarine bases had to be heavily defended. This decision was executed by the Organisation Todt (OT), the Third Reich civil and military engineering group. Over 600 approved types of bunker and casemate were listed in a book called the Regelbau (english:standard build). Each having specific purpose with standard features, such as an entrance door at right angles, armoured air intake, 30mm steel doors, ventilation, communication systems and emergency exit system. The standardisation simplified the manufacture of the equipment, the supply of materials and the financial control of the construction as well as the speed of planning for construction projects. Within 2 years, most of the planed fortifications were built.
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Bego, France
Bunkers
Construction The material were sourced on site and for most of the bunkers the concrete was poured on site as a homogeneous block. The bunkers were monolithic, without fondations—they are one of the rare modern monolithic architecture—which became a major quality in the dunes: the concret block only depends on its gravity center and allows movements without major damages. This is how we can nowadays observe titled specimens without serious damage. Also, all their outside angles are rounded to be more robust to firing attacks. These qualities also allowed most of them to remains the same as after the Allied landing even though though out the years some drifted in the dunes and slowly disappear in the Ocean eaten by the salty water of the sea. Current knowledge Apart from the pioneering book Bunker Archaeology by Paul Virilio, it is pretty recently, around 10 years ago, that we began gathering a serious amount of informations concerning these constructions in France. As the Nazi destroyed all the documents related to this period when they lost the war, informations were gathered thanks to passionate people redrawing plans and sections from site measurements, others kept by local french concrete companies that helped at the time of constructions, testimonies from locals and former soldiers were gathered in a handful of books. The researches are still pretty active, using internet as a main
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Bunkers
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1945
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2016
Bunkers
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4 One of the 4 main bunkers for canons
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Bunkers
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5 Shelter SK for 26 people
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Bunkers
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Tobrouk 58C
Radar V229
Hospital
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Bunkers
Hospital
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Shelter SK for 10 people
Bego, France
Bunkers
Shelter SK for 10 people
Shelter SK for 26 people
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Command post
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Bunkers
Fl 242 AA ( anti-aircraft )
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Fire control tower
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Bunkers
Electric shelter
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Ammunition depot
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Bunkers
Ammunition depot
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Bunkers
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communication media between the communities involved. Associations all over France were created for the management of these war vestiges, gathering informations, organising visits etc. Nowadays we believe all typology of bunkers on the french coast are identified and documented. According to Admiral Jean Lemonnier, who in 1944 established a complete list and the plans of fortifications and obstacles built by the Germans on French shores, the Atlantic Wall comprised 15 000 concrete works, of wick 4 4000 were major works and 9300 artillery batteries. Each system of coastal defence, support station, or naval battery was buttressed to a major post, itself transformed into a fortress ( copy past from bunker archeology book p62) To name them, a specific code is used. The abbreviations R, Fl and SK preceding the code corresponds to: for R, to Regelbauten (construction rules) and concerns all the standardised pieces. for FL, to Flugabwherkanone or Flak and represent all the anti aerial pieces and finally SK corresponding to Special Konstruction or Sonder Konstruction names the ones not referenced in the OT catalogue, aiming to reply to a special demand. All the referenced piece have a number following the letter R, giving more information about their purpose and characteristics. For instance a R621 is a shelter for soldiers with one room and a R622 is the same model but with two rooms. Within a position we find a variety of building works. The most important points or StĂźzpunkt (Stp), have a great amount of fortifications whereas
Bego, France
Bunkers
the smaller ones Widerstandnest (Wn) have at the minimum posts for machine gun (Tobrouk or Ringstand) with a shelter for soldiers. Flora Fauna of the bunkers as part of the dunes Since 1945, most of the bunkers are abandoned, left to the nature. They became cave-like environments, with very little sun light and high humidity rates. In Brittany, the caves are very rare—not to stay inexistent—and the fortifications of the Atlantic Wall became homes for number of species living in caverns and appreciating the littoral climat, like bats or butterflies. Before the bunkers were built these species weren’t part of the dune’s fauna, these construction brought an entire new world to this biosphere. Most of them are hibernating through out the winter. It is the case of the butterflies and moths. With the first slight chill being felt on early September, the hibernating butterflies find refuge in shelters. Bunkers, caves and other attics provide them with stable temperature ( between 2°C and 8°C) and a sufficient hygrometry. For instance groups of lepidopterans chose this option to survive the winter. Bats naturally belongs to the caves. In meridional zonas of France, they are often noticed in their original shelters. In Brittany, they mostly find refuge in attics but other places like concrete bedrock, feodal towers, old mines and abandoned bunkers often have ideal conditions as well. To hibernate, bats look for places with a stable microclimate (as the
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Bretagne Vivante - SEPNB Société pour l’Etude et la Protection de la Nature en Bretagne 186, rue Anatole France BP 63121 29231 BREST Cedex 3 Tél. : (+33) (0)2.98.49.07.18. Fax : (+33) (0)2.98.49.95.80 Email : bretagne-vivante@bretagne-vivante.asso.fr Site : www.bretagne-vivante.asso.fr
Bego, France
Bunkers
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Bego, France
Bunkers
butterflies) often found in bunkers : high humidity and temperature from 8°C to 10°C. However bunkers are unequally favorable for bats, typologies that allow high humidity and absence of air-stream are the best. During their hibernation period the bats are extremely sensitive to the current humidity and temperature in the space, the only presence of one humain can change these conditions and disturb them. At the moment several bunkers have metal gate on their access to prevent humain visitors to enter them. Though the years and after abandon, the bunkers became home to a new and sensitive fauna. However this fauna inhabits them mostly during the winter, a time period when the surrounding areas and therefor the dunes are not so frequented. We could imagine that instead of building permanent barriers—as the metal gate—we cover the access only during the winter with a structure that is modular enough to be removed for the summer for the bunker to be reopen to the public during the summer.
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Materials of the site
Materials
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Materials
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Materials
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Materials
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Site layers
Site layers
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History layer
Bunkers
Site layers
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WWII railways
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WWII trenches
Site layers
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Circulation layer
Roads
Site layers
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Railway
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Informal walking paths
Site layers
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Bego, France
Flora layer
Trees
Site layers
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Bushes
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Grey dune
Site layers
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References
References - Virilio, P. - Bunker archeology - Princeton Architectural Press, 2014 published for the fisrt time in 1975 in France under the title Bunker archéologie - Tomine, J. - Le mur de l’Atlantique dans la presqu’île de Quiberon Edition Histoire et Fortification, 2010 - Rolf, R. - Regelbauten, Atlantic Wall Typology - Prak, 2015 - Atlantik Wall, Mythe ou réalité - Alain Chazette - Les bunkers de dunes d’Etel-Erdeven - Study by Jacques Jouannic - Bretagne environement - Les dunes en Bretagne - Août, 2009 - Grand Site Dunaire, Natura 2000, Life - Maintien de la biodiversité littorale sur le site “Gâvres - Quiberon” - 2014 - Operation Grand Site National Gâvres-Quiberon - Etude paysagère 1999-2001 - Araignées des bunkers - Study by Jacques Jouannic - Papillon des bunkers - Study by Jacques Jouannic - Intérêt pour les chiroptères des bunkers du grand massif dunaire de Gâvres-Quiberon - Olivier Farcy
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