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MontstMichel.co.uk  2010

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The Bay  

at Le Mont Saint Michel

The Bay

The Bay

For many years, the bay around Mont saint Michel is considered a must see and a place to be explored when visiting the Mont. However in recent years the bay has become important for more than just tourist and sight seers, since the arrival of ecology scientific studies that have been carried out all over the bay due to the bays surprising natural phenomena.

The Tides

Low tides and High tides more or less constantly vary from a few centimetres to quite a few meters,

There is in no other place in the world apart from for the Bay of Fundy in Canada, where the tides differ as much as at Mont St Michel where the variation between low tide and high tide can be to the extent of fifteen meters.

Due to the pull of gravity exercised by the moon and by a less amount by the sun on the oceans, of the world the tides rise and fall two times in every lunar day of 24 hours and 50 minutes. When the sun, moon, and the earth become aligned, or are close to this alignment an astronomic phenomenon known as syzygy takes place. The draw of the two celestial bodies, together, provokes extremely strong tides, known also as the spring tides. This phenomenon is mainly apparent through the spring and autumn equinox, but more spectacularly at the times of the new and full moon. High tides surround saint Mont Michel around every seven solar hours, eight hours in winter and nine at summer time.

The extraordinary tides in the bay of Mont-Saint-Michel are because of its geographical location. The movement of the tide, coming in from the Atlantic sea, hits the Cotentin coast (Cotentin coast is part of the Normandy coast line) like it’s a wall, and the tidal water breaks on the coast before going in to the bay which is half bowl shaped. In this virtually level area, it is apparent that a range of fifteen meters turns into a huge distance. In periods of the spring tide, the low tide goes out as far as 18 kilometres from Mont-Saint-Michel. The flood tide of the sea, which once rose into the Couesnon River, could be seen as far as Antrain a department of Brittany, more than 20 kilometres inland. The tides consequently went inland as much as 40 kilometres, a distance covered by the sea in no more than six hours. Not possibly with the speed of a galloping horse, as told in wives tales, but all the same somewhat remarkable. The haste with which the tide moves is the major danger in the bay where misfortunes infrequently occur. A stroll along the beach conceals could lead to unforeseen hazards for any person which neglects to learn in advance just when the high tide will come in and even how high it's going to go, and even for any person who does not make certain they are back at the Mont sixty minutes or at least an hour and a half prior to high tide. It really is almost hopeless for any person on their own to flee from the currents and whirlpools which characterize the tides.

This kind of serious hazard is flanked by that of the quicksand’s, consciously exaggerated through legend. The deviations of the coastal rivers into the bay have left behind them old water holes filled with fine sand in suspension, covered by some sort of weak dry crust, which may quickly cave in beneath the weight of any person. In fact, the actual quicksands tend to be much rarer than history might guide someone to believe. Neither should they be mixed up with all the levels of mud, a slimy build up of fine sand as well as fine clay that makes up one of the sedimentation levels of the bay. So remember when visiting the bay to keep an I on the tides.

 

Silting

Within the bay, of Mont-Saint-Michel the occurrence of sedimentary build up is speculated that the progressive silting will course an upward build up of land that might before too long endanger the maritime personality of the bay. At first look, it would appear to be a natural motion, typical to all bays of the world. The flooding tide is more powerful compared to the ebb tide which means that a lot more alluvial earth is brought in than out. This particular alluvial earth left by the sea fills in the anfractuosities of the shorelines, gulfs plus bays. All-around Mont-Saint-Michel the amount of sea deposits is estimated being close to three hundred thousand cubic meters annually.

Typically the lighter in weight particles are usually deposited close to the shoreline, where they form muddy sand (called ‘tangue’) that includes a combination of really fine particles of clay, delivered down through the coastal rivers, as well as small fragments of sea shells. At one time, this particular greyish sludge had been used to fertilize the nearby lands.

Once deposits introduced by the ocean have elevated the amount of the land sufficient to put it out from the reach of tide, plant life that will be able to endure large proportions of sodium (salt) eventually begin taking hold, to begin with saltwort along with sea-fennel. An area is actually consequently established which the occupants of Mont-Saint-Michel name ‘herbu’ (grassy) much better recognized with the rest of the planet as salt marsh. This type of plant life subsequently helps to retain the sea sediments, accelerating the process of silting. For hundreds of years, the bay of Mont- Saint-Michel seems to have prevailed in avoiding this unique occurrence. The presence of various water ways down the coast of the Couesnon, the river of Ardevon, the Guintre, the river of Huisnes, the Selune and the See, alongside the array of tides reveal the reason why. Each one of these rivers, no greater than a rivulet in the period of neap-tides, became a hastening flow when the tides permeated inland and flooded huge regions of swampland. At low tide the particular, substantial masses of water formed and went back towards the ocean, creating extraordinary waterfalls that swept the bay clear of all of the debris remaining from the high tide. The change of these waterways in the direction of the bay occasionally carried them up to the coast where they are able to significantly ruin crops. Tradition narrates that numerous seaside villages vanished totally during the Middle Ages. The very first attempts to be able to transform the fertile muddy sand of the bay into arable terrain date towards the eleventh Century, around the beginning of the Thirteenth century, the bishop of Dol requested numerous dams to be built which could protect the black swamps from the ocean also the rivers. Mont- Dol, that at one time raised upon the timeless sand just like Tombelaine and Mont-Saint- Michel, found itself enclosed by land. Up until the finish of the Nineteenth century, however, the location between the rivers, See and Couesnon continued to become at the mercy of powerful currents that made it impossible to build polders and reclaim the land.

The concession granted Mosselman and Donon within 1856 was a turning point in the history of the bay. Because of the modern methods imported from the Netherlands, the Couesnon was canalized approximately less than 2 kilometres from Mont-Saint-Michel. The waterways See and Selune were deviated northwards because of a submarine dam, established on the rugged point of Roche-Torin, also the several water ways that previously ran in to the Couesnon also the Selune had been additionally redirected here. Protected from the deviation of the waterways, the base of the bay therefore grew to become a massive compartment for sediment.

The constructing of a causeway in 1877, regardless of resistance from the State Authorities of Fine Arts, has been one more phase in the polderization that was concluded within 1936. The Association of the Friends of Mont-Saint-Michel had been arguing for 15 years to keep the Mont an island, even though they were not successful in stopping work on the causeway, they succeeded in obtaining the community forces to be able to restrict the actual arable lands to no nearer than one and a half kilometres from the Mont.

The development of brand new polders had been therefore discontinued permanently. Yet this didn't get rid of the modifications that had been made to the rivers within the bay, the main reasons for the silting up. Certainly the grasslands nevertheless continued increasing in the direction of Mont-Saint-Michel. Scientific studies were started in 1974 in an attempt to discover away that may enable Mont-Saint-Michel to sustain its ocean going personality without infringing on the legal rights acquired by the farmers of the polders. Backed by the Central Hydraulic Laboratory, all of these scientific studies have shown that it was achievable to reduce the level of the sands through putting back the water holes, which, up to the Nineteenth century, had kept the bay by natural means clean.

The technicians specified plans for 3 stages: first, the basin of the Couesnon needed to be controlled so that the tide seas could flow to the lower course of the river and constitute a basin which would quickly empty with the ebb tide. The 2nd stage offered was for the creation of a number of man-made tide reservoirs, which would perform on the same theory, towards the east of the causeway. The 3rd stage comprised in the dismantling of the dam of Roche-Torin, in order that the See and Selune rivers could deepen the eastern area of the bay.

Work started in 1983 on the 3rd stage, which was the easiest from the technological and juridical perspective. The regulation of the Couesnon basin will be carried out pretty shortly}, in the hope that the pessimistic prediction of the Central Laboratory of Hydraulics that the point of no return was reached in 1991.In more recent times the new Couesnon dam was finished in 2010 and there is now plans on removing the causeway which was built in the late 1870s. Now only time will tell if all this work will reduce the current silting.

 

 

 

The Wild Life Of The Bay

The dredging of the area will certainly have an effect on the wild life of the bay, the reduction of the meadow zones and as a result the number of sheep that graze on the salt marsh. This unique race was selectively bred in the Avranchin in the Nineteenth century and can be very easily recognized by the form of the head and the dark coloured legs. Feeding upon these types of grasslands, their tasty meat is famous and appreciated in areas faraway from Mont-Saint-Michel.

The wildlife, which is made up mainly of wild birds, is a lot more heterogeneous. The bay constitutes a perfect sanctuary for migratory birds, particularly the anatides that spend the winter months here. There's also several ducks, prevalently mallards but additionally rarer varieties such as the Sheldrake’s of Belon, which nest about the polder dams and the reefs of Tombelaine. With a little good luck, watching the shore it may also be possible to see a barnacle-goose or perhaps some other type of wild bird. Whilst these types of migratory birds winter here, there are others for whom the bay of Mont-Saint-Michel is but a way station: herons, pink flamingos, and more rarely a wild swan.

By far the most numerous, however, are those birds whose natural environment is the bay. All sorts of gulls, sea swallows, and even an occasional big cormorant.

The bay is also inhabited by additional wildlife but they are more challenging to see the fish, primarily grey mullet, flounders, bass. In the Nineteenth century, fishing had been one of the principal actions from the occupants of Mont-Saint-Michel while the ladies collected the small clams which resided within thick banks in the sand. So we can only hope that the wild life of the bay will adapt to these changes well.

Photo of Mont Saint Michel And its Bay

Photo of the Bay

Photo of the effects of Silting

Photo showing sourounding water ways of the bay

Photo of the Couesnon River msm in the back drop

Photo showing construction of the new dam

Photo of the new Couesnon dam

Photo of the Avranchin sheep