Grottes des Planches

Cave of the Planks


Useful Information

The ceiling with corrosion forms.
The profile of the passage.
Location: A36 exit Dole, N55 km from Arbois. N83 via Poligny and Besançon.
Open: closed.
[2020]
Fee: closed.
[2020]
Classification: SpeleologyKarst cave Speleologyriver cave.
Light: LightIncandescent Electric Light System
Dimension: L=7,860 m, A=400 m asl., T=12 °C, 6 °C (water).
Guided tours: D=60 min. V=30,000/a [2010]
Tours in English Deutsch - German after appointment.
Explainatory texts in English Deutsch - German Italiano - Italian Netherlands Español - Spanish
Photography: allowed
Accessibility: no
Bibliography: Frédéric Poggia (2017): La grotte des Planches Scialet: bulletin of the CDS of Isère, Grenoble, Departmental Committee of Speleology of Isère, no 46, 2017, p. 101-105 (ISSN 0336-0326).
Address: Grotte des Planches, 14 rue de la Baume, 39600 Les Planches pres Arbois, Tel: +33-384-661374, Tel: +33-384-660793, Fax: +33-384-665610.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then.
Please check rates and details directly with the companies in question if you need more recent info.

History

The lower water filled passage, the path is mounted to the wall high above the river.
1813 kids from Arbois enter the cave entrance and discover Bronze Age tombs.
1904 first scientific exploration, first survey.
1935 start of development.
1936 opened to the public.
1946 cave reopened after World War II.
1947 giant dolly tubs added to the tour.
1975 archaeologic excavations.
2006 rockfall from the cliff face.
2010 rockfall from the cliff face.
2011 closed for security reasons.

Description

A typical passage in the cave, the path is built to the wall of the river cave.
Two dolly tubs connected by a canal, formed by the flowing water.

Grotte des Planches is located at the end of a typical reculee, as the steep valleys of the Jura are called. The cave at the end of the Planches Blind Valley is the source of a small river, one of the sources of the Cuisance river, and most of the cave passages contain a cave river. The path is most of the time attached at the cave walls, high above the river.

The cave is entered through a higher level, a now dry cave passage with impressive profiles and very little speleothems. Here is a small collection of items which were used to develop the cave, like a wooden boat and a wooden wheelbarrow. Then the path narrows and a winding stair leads down to the still water filled level.

The tour visits two different passages of nearly the same level. One is a little lower and is the bed of the cave river. First the path is high above the river, attached to the wall of the cave. The river below is calm and deep, as the cave passage is quite big. But when the passage narrows, the trail is only one or two meters above the water. The river forms rapids and the passage is gorge-like. Then the character of the cave changes again and the path is only a bit above the river bed. This part of the trails is sometimes flooded after heavy rains.

A short connection leads to a parallel passage, which is a little higher. It is flooded only in times of high water, like the snow melt in spring. At this time the passage is filled with a roaring stream of water. But most of the time this passage is very dry.

It is obvious that this was much different once. The floor of this passage is covered by enormous and extraordinary Explaindolly tub, which are the unique and impressive main sight of this cave. Nearly circular bowls with steep walls and flat bottom, typically between 50 cm and 100 cm in diameter and up to one metre deep. Some of them show the extremely rare child tubs, where the flat floor of the dolly tub shows three small child tubs, arranged in an equilateral triangle. The absolute highlight is a tub where one child tub shows "grandchild" tubs. Most of the tubs are dry during the summer, a few contain some remains of standing water. They cover the floor of the 100 m long passage.

The cave was developed in 1935 by Emile Bonnivard. He bought land, leased the cave from the commune, built a road and channeled the river below the cave. Inside the cave he installed wooden bridges and lowered the water level by digging a channel between the Grand Auditorium and the top of the waterfalls outside. Actually the modern tour is still based on the route he designed 70 years ago. The cave was operated by the Bonnivard family until its closure.

From 1990 to 2011 some cave divers regularly explored the cave and the surveyed length of the cave was extended to 7,860 m. The divers Frédéric Poggia and Thomas Parnet made several dives into the siphons upstream. The exploration was supported by the operator Guy Bonnivard and Bernard Guillot the mayor of La Châtelaine. There is a municipal ban on diving in the cave which was temporarily lifted for the exploration. The explorations ended when the cave was closed.

Unfortunately the cave was closed in 2011 due to security reasons. The cliff face above the cave entrance produces falling rocks which are loosened by frost weathering. But in 2006 there was a bigger rockfall and it was necessary to secure the cliff face. The cost of EUR 16.000 was divided by the three neighbour towns and the operator Guy Bonnivard. But another rockfall in winter 2010/2011 was even bigger and more costly, it was estimated EUR 60,000. Again the operator asked the towns to pay for the cleanup, but this time the towns refused. Quite understandable as they are really small and all three towns together have only 800 inhabitants. Hubert Darbon, mayor of Planches-près-Arbois, explained that the original lease from 1934 was never updated and the rent of EUR 247 per year not realistic. Also the expert from the Bureau de Recherches Géologiques et Minières, who checked the situation, discovered numerous security issues with the show cave. The operator obviously decided to close the cave instead of doing all necessary upgrades. In Autumn 2011 the cave was finally closed.

As the Grotte des Planches is now closed for 10 years it is unlikely it will be reopened. That's quite sad, as this cave was unique, it is a river cave with exceptional dolly tubs, you can see nowhere else. It was not only unique in Jura, we have actually never seen such tubs in any other cave.


Grottes des Planches Gallery