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The time counted dune soarings

Courtesy of the author (Vincent Chanderot), I warmly thank, I publish here a reflection on the soaring dune.


Winter 2014 resulted in a comprehensive and very significant decline in the coastline of our coastline. However, while some sites were irretrievably chewed, other soarings have mysteriously reactivated. The big bites in dune profiles too flat, added to an erosion of several meters thickness ranges accentuated slope height and slope, temporarily creating more favorable conditions to theft. Petit-Nice from the beach, for example, the dune fell 8 meters and the beach has lost 2 meters thick. In both cases, regression of the dune or transient appearance of dynamic conditions, the situation is worrying and the flight suspension beachfront.

The sites undergo dynamic beach-dune couples

The dune forms a system connected with the beach and the funds which border. During winter, Dune is a reserve of sand where waves come to draw the benefit of the foreshore bar, so that the powerful swells pounding away from the edge. Some months later, it is the turn of small summer waves to lap the beach and re-fertilize its sand. The grains find the dune, carried by the breeze, unless they are lost in the heath if they do not cross a plant that can stop their race. A degraded dunes and is the assurance of seeing the convicted beach.

Erosion of winter 2014, with a retreat of the coast 5 20m, exceeds all observations for over 50 years. Fortunately the following winter has not seen so many synchronous storms with high tides by whitewater, but serious questions remain about the sand, which did not redeposited during the summer : wild parts of our coastline have faced this winter and the next can be without this rampart.

A natural phenomenon accelerated by man

The retreat of dunes is a trend on many sites, her to get even worse. For that flew in Capbreton, Nice to small or Wissant, Flooded bunkers of the Atlantic Wall recalls as evidence that the advance of the ocean is not a phenomenon that dates this winter, even if some sites earned the sea there a few decades. The phenomenon, however, every reason to increase in the future, with the rise in sea level, climate change, (generator more disruption) and urbanization. This last factor is aggravating, because a road or parking dune edge can not hold the sand, which will ultimately lost forever in the land. Urban pressure is moreover provider of stompers, including the night shift to fixing vegetation and dug-whistling winds. The waves and the wind snapped the sand dunes, but the trampling that night on his return.

The sites are always more likely to be allowed to walkers and paragliders, to the surprise of those who remain convinced that oh great paragliding never touches the ground. The goal is always to remove the trampling of plants stabilizing the dune, who are the only natural stabilization of existing tools and effective. Their aerial parts intercept the sand, which is found set by the root system, but the existence of this vegetation often hangs by a thread in this hostile environment, extremely poor and salty. Some stamping sufficient to arrest growth of the plant and, on the slope, to uproot.

Accumulation of small innocent gestures

On the Southwest beach, by a somewhat irregular wind, some fellows full of goodwill. The most impatient trying some takeoffs before the wind really establish, collapsing them with fine sand volumes. One that barely make gas persists tweezers tufts of grass at low altitude and pierce bushes. Many are surprised by the soft and land on the ridge and then trying to take off again on or leave by walking on the dune. The Stakhanovite of wagga must unravel its lines taken from an old fence five times per hour. Some are shifting and posed in the gray dune while the champion smashes on a small barrier whose purpose, when she stood, was to keep away pedestrians who relish the show.

In this sequence appears authentic whole issue. A paraglider is rarely alone and if you are irreproachable in addition to being a talented driver, those who follow him will probably be less, as the curious walkers. A few centimeters of altitude, there are only cases of force majeure, and not always for alternatives when it comes to land. In these cases, too bad for oyats painfully trying to recolonize the environment. When it comes off again or pick sailing in prickly leaves, it is not certain that the paraglider make the choice to preserve the fragile panicaut, at the expense of its equipment or time of flight. Housework before takeoff so that twigs get caught in the lines seem trivial, But this simple act deprives the sand dune in additional traps.

Anticipating rather than deny

Buttress the idea that the paraglider never touches earth is a good way to be banned sensitive sites futures, for the battle is lost in advance : set foot on the dune is already prohibited by law, we enjoy only sometimes even a tolerance, he should not be abused. Certainly, pedestrians are more, indeed it is surprising the many new buildings in violation of the Coastal Law, but it is they themselves, and we is us. The pioneers who had the opportunity to observe the evolution of the sites, them, do not deny their responsibility in erosion, although there has 25 years, it was not aware of it. We may regret that FFVL, in his charters, does not produce instructions for soaring on the dunes, because if the paraglider may seem an indispensable asset to a resort, there is often nothing. « We do not consider paragliding as a force for the Dune du Pilat, we just think that it is not incompatible, for the moment », we confirmed Maria De Vos, Director of the joint association managing the large dune, famous soaring site if any. Also everyone should understand the interest to work with the NFB and the conservatory, owner of the most exceptional sites as the Pilat for the sustainability of paragliding.

The Dune du Pilat, great soaring site in motion

Like the great African barchans once deprived of their vegetation, the highest dune in Europe is mobile. The Dune du Pilat result of a stack of several dune growth phases, interspersed with long stagnation, marked by the presence of vegetation cover. His ancestor nineteenth century dune called the Grave, it only measured 80m in height and stood over 500 meters west. The crop eradication pine that covered has increased transportation of sand in the wind, at the expense of forest (and today campsites). The phenomenon is still extends speed 1 5m per year and it is no longer considered fastening technology, given the use of the site and extent of the task. In the sector wagga, one can clearly observe the step between the southern part of the big dune, naked, receding and the covered section of vegetation opposite the campsite, whose slopes have undergone clamping arrangements. A little further south, the morphology of the site has changed considerably since the explosion paragliding. The consequences of trampling places specifically frequented by paragliders are flagrant. The dune withdrew about a hundred meters in twenty years to Gallouneys, was that there is little long and stiff right wall before will become insignificant that combe. The NFB is committed to delineate areas of Deco-atterro open alternately, to promote the reconquest of the environment by vegetation. The future of the site remains uncertain. It is especially subject to changes Banc d'Arguin (the sandbar facing it). If he were ever to link up with the beach, then there would be more problems for a long time. but now, it supplies very little this range, his sand escaping to the south by Salie pass from Arcachon.

Story of a disappearance

The retreat of dunes in weakly urbanized areas raises the problematic question of the survival of the sites on the highly urbanized coast. The dunes on which they built (Lacanau, Capbreton…) can not turn back time to a, nor nourish the beach. These are fields of ruins successor to former inexorably soaring sites.

The sand is becoming scarce in many parts of the world. It is drawn in excessive amounts in the seas and rivers to amend agricultural soil, manufacturing glass and especially concrete (the desert sand, too round, is not suitable). Many beaches have disappeared, when they are not on a drip, because all attempts to maintain artificially systematically been unsuccessful. Redeposited sand by the ton on the beaches has no more reason to hold up that it replaces, As the natural dynamic between dune, beach and ocean is not restored. dikes, if they can save face locally, aggravate the situation downstream and cleaning debris from the water line for the convenience of tourists does nothing to fix the situation.

Sand grains are torn by the mountains and the streams run aground on the dunes after a millennium journey. There no longer exists any river whose course is not hindered, between its source and the ocean, by dams which stop the course of the greater part of the aggregates. The sand is lacking today in Aquitaine beaches is held or operated in the tributaries of the Adour-Garonne basin.

Instructions of the dune

On l’a vu, the conservatory, NFB or town halls strive to protect some paragliding sites from erosion, sometimes by regulating the practice. We can help to keep the paraglider on the sites still allowed by an exemplary attitude. Do not condemn an ​​entire community by a selfish attitude. Opt, without platform, inflation on the beach and try to take off, if possible on a path. Trample the least possible slope of the dune in particular avoiding vegetated areas, try to use all the same passages, never land on the crest or on the dune, never trample plants or remove branches. Know especially wait or give up if the conditions are not perfect.

 

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