Arcachon is one of the 23 main French ports defined by the national hydrographic services.
So to draw our tide curves for the Bassin d'Arcachon, we use the official predictions issued by the national hydrographic services.
Therefore the predictions used are those of the port of Arcachon (Eyrac pier)
Here are the coordinates: Latitude 44°40'N / longitude 001°10'W.
The Arcachon-Eyrac tidal zone is delimited by the SHOM. It results both from tradition and from a very ancient observation.
In Arcachon the hydrographic datum is located 6.518 m below the NGF mark (general level of France) located on the facade of the ROC hotel.
In the Bassin d'Arcachon the average tide level is 2.48 meters
By way of comparison, this average level is 6.76 m for the main port of Saint-Malo and 3.20 m for Les Sables-D'Olonne.
Fixes on the tidal zone
SHOM, the reference hydrographic service, defines so-called “attached” ports spread over the Bassin d'Arcachon which require corrections to times and heights in relation to those of the Eyrac pier.
Thus below 3 places of the Basin and the corresponding corrections:
First at Pilat plage: times from – 5 mins (low tide, neap tide) to – 25 mins (high tide, spring tide)
Pilat beach: heights of – 0.20 m to – 0.30 m for the open sea.
Second at Grand Piquey: times from 0 min to + 15 min (high tide, spring tide)
Grand Piquey: heights from – 0.05 m to – 0.15 m
Third in Cap Ferret: times from 0 min (low tide, neap tide) to – 20 min (high tide, spring tide)
Cap ferret: heights of – 0.05 m to – 0.15 m (high tide) and + 0.10 m to + 0.15 m (low tide)
How are the tides in the Bassin d'Arcachon?
We can say that the Bassin d'Arcachon fully experiences the tides and that this phenomenon has a strong impact on its geography and its ecosystem.
The particularities of the tides in the Bassin d'Arcachon
Description of the Arcachon Bay
First of all, the Bassin d'Arcachon is a semi-enclosed lagoon with very diverse landscapes.
On the side of the La Leyre estuary on the Teich and Biganos side, the landscape is more “Pré-salés style”.
Then many esteys and channels in the lagoon as well as sandbanks, beaches and passes at the level of the opening towards the ocean change according to the tides, the wind and the swell.
Indeed the tides move the sandbanks, modify the passes, and carry millions of M3 of water at each tide.
The delta of the mouth is different according to the rising tide or the falling tide. Therefore it is important to inquire at the harbor master's office to obtain the latest information on the positioning of the sandbanks and passes at the entrance to the lagoon. Obviously this depends on the tide and the period of this tide.
High tide or low tide
At low tide we discover the sand banks of the Bassin d'Arcachon as well as the omnipresent mud, more than 100 km2 of foreshore.
When the sea recedes, it uncovers more than half of the Basin.
The times of rising and falling tides are not the same.
Indeed, it takes longer for the tide to rise, and the slack of high tide is longer than that of low tide.
Evening and winter high tides are always weaker than morning or summer highs.
During spring tide, the tide delays less from one day to the next.
The Bassin is a space in perpetual motion ¡
It is necessary to take into account the wind which can modify the values of heights of more than one meter. A strong southwesterly wind can generate significant corrections. Caution !
The importance of the tides for professionals in the Bassin d'Arcachon
Many of them live from the sea, around 300 oyster farms and a hundred professional fishermen in the Basin.
Oyster farmers must know the tides to be able to work in their oyster beds. They start their barges (flat-bottomed boat) to go to their parks at low tide, time is running out.
The work lasts between 4 to 5 hours at the right time of the tide. The oyster farmers take advantage of the low tide to turn the oyster bags and carry out all their work.
Then you have to leave at the rising tide.
The tide will rise to gradually submerge the Bassin d'Arcachon and the oyster beds.
You can spot the oyster beds thanks to the Pignottes (wooden sticks planted in the sand). They make it possible to locate the parks at high tide and to delimit them.
To the rhythm of the tides of the Bassin d'Arcachon
What to do depending on the tide Ɂ
The bench of Arguin
Start by visiting the vast Banc d'Arguin at the entrance to the Bassin. This sandbank is a natural reserve of blond sand and clear waters. At low tide it extends over 4 km long and 2 km wide, a small island of paradise!
Try to sail on the Basin and head for the ocean. However, before any departure, check the tide times and the coefficient as well as the weather, the wind and its direction and generally know the state of the sea.
Pay attention to the passes!
At low tide
Then visit the oyster beds with an oyster farmer at low tide.
Also go fishing on foot to discover the fauna, flora and other shellfish. But “not touch the oysters”.
If you do not know the territory well, come back as soon as the tide begins to rise.
Note that the Pereire sandbank at low tide is ideal for discovering seagrass beds, seaweed and its entire ecosystem and for starting shore fishing.
The Tchanquées cabins
Finally, discover the island of birds, its Tchanquées cabins and its ornithological wealth. Boats can only approach the huts at high tide.
Tides and weather in the Bassin d'Arcachon
During the change of tide on the Bassin d'Arcachon, the sunshine, the wind and the cloud cover are sometimes brought to turn.
Meteorologists attribute it to 2 local specificities:
At the change of tide, a huge volume of water enters or leaves the Basin. This generates strong sea currents and temperature variations that influence the movement of clouds.
In addition, the Pilat dune at the entrance to the Bassin creates hot air updrafts.
The locals say that the weather in their basin is better than in the region as a whole.
Tide times for Arcachon
The Tide Calendar allows you to visualize at a glance 12 months of tides. This wide-angle visualization makes it possible to better plan and anticipate all maritime activities.
The tide calendar is an essential tool in the Bassin d'Arcachon.
It will be a nice souvenir of your visit to the Bassin d'Arcachon.
Concept The Tides
Our concept is innovative and aesthetic, it dusts off the presentation of predictions.
The title of the calendar corresponds to the tidal zone: BASSIN D'ARCACHON
We draw twelve curves for 12 months of tidal predictions.
The curves are proportional to the tidal coefficients established for each high tide. The coefficients tell us about the relative importance of the tidal range (difference in water height between 2 successive tides, high and low).
The tidal coefficients are plotted on the middle of each curve.
The high tide times and heights are above the curve as well as the day of the week and the date. Dotted lines bring together the 2 daily high tides.
Times and low tide heights are below the curve with day and date. Dotted lines bring together the 2 daily low tides.
A didactic calendar
A child can follow the curve with their finger to visualize and understand the movement of water.
The tides and the moon
The calendar is also a lunar calendar. The phases of the moon are shown there. The link between the phase of the moon and the tidal cycle becomes obvious. Indeed during the new moon and the full moon the curve is wide, the tide is of the spring tide type (the water rises and falls a lot).
During the first or last quarter, the curve is tighter, the tide is of the neap tide type (the water rises and falls less).
Spring and neap tide
At a glance, by looking at the curve on the desired date, you know if the period is spring tide or neap tide. The tidal ranges range from 3.90 m during spring tide to 2.1 m during neap tide.
High tide periods are highlighted by a yellow bar on the line of tidal coefficients in the middle of each curve.
At a glance, all the high tides of the year and their dates are visible, which makes it possible to plan and anticipate these periods.
By convention in France, high tides exist when the tidal coefficient is equal to or greater than 100 on our coast.
The hours of the calendar are the legal hours in force, summer hours UT + 2h and winter hours UT + 1h in progress.
Heights are expressed in meters. They are expressed in relation to the hydrographic level 0 of the zone. The 0 of the nautical chart to which we add the water height. The water levels are always positive on the French coast because the hydrographic 0 has been positioned at the lowest.
We specify the reference port of the data used to draw the tide curves at the bottom of the calendar.
Likewise, we carry our license number for the use of official data on the calendar. It is forbidden to reproduce the data and our design without prior permission.
Exhibit The Tides of the Bassin d'Arcachon
The Tides posters and paintings are carefully printed on matte or light wood paper in the classic 60 x 80 cm format.
Each table and poster bears the title of the tidal zone to which it corresponds.
But Les Marées also offers a choice of content. Why not personalize the Calendar with the recipient's nickname, the name of an unknown little cove in a tidal zone or the name of your family home? Choose your title!
Offer the predictions of the tides of the Bassin d'Arcachon, it is the gift appreciated by all surfers, fishermen, sailors, oyster farmers, swimmers or simple walkers.
The Tide Calendar exists for all the tide zones of the Atlantic coast, the English Channel and the North Sea.
We print on demand, no stock or superfluous manufacturing.
we print on matte paper and on poplar wood from sustainably managed forests.