For one year now, I have been working on an incredible dive project which is not just a simple spring, but a legend. The place is located in France, in the little city of Tonnerre, in Burgundy, land of good wines and old castles.
This spring is unique, located in an old town, known since the dawn of time. Diving has been prohibited since 1996 following dramatic diving fatalities. That year, 1996, was also the beginning of my life as a cave diver. For 23 years I had dreamt about diving in the Fosse Dionne.
Two years ago, I read in a newspaper that the new mayor had authorised some dives, but only under control and for specific projects. Immediately, I sent my book about cave diving, some pictures and my project for the Fosse Dionne. I didn't request access just for cave divers or for myself. I offered to clean the pool, to put in a new line, to carry out a survey, to take pictures and make videos and to make a global study of the place.
After a long wait and some meetings, the mayor of Tonnerre accepted to open the spring for a short time on my behalf. Bingo....! Authorization was given for 2018 and later for 2019. Now, each month, I dive in the Fosse Dionne to do as I proposed - clean the pool and its entrance.
For 23 years, people have dropped phones, toys, bottles, beer cans and even a fire extinguisher in to the water. I laid a rope in the first part of the cave and we started to take pictures and make videos. Of course, we also started a survey of the cave. I can't do everything alone, and have invited a few divers to help me on this project, to clean, take pictures and survey.
Why isn't this a simple spring ? Why is it a place of legend ?
The place is incredible and unique. A wash-house was built here in the 17th century and no place in the world looks like it. Many old legends are attached to the spring. Famous French cave divers, the Le Guen brothers followed by Patrick Jolivet, took the line deeper and as far as possible. There are three squeezes, two close to the entrance (or the exit) and one at the beginning of the deepest section. All fatalities took place between the two restrictions when divers tried to exit the cave. In these cases, divers pushed the twinset backmount in front them, in a very significant slope, and most of the time with no visibility. Actually, with a sidemount and a good trim, the dive becomes easier.
The cave is really beautiful. The stone's textures and colors are absolutely fantastic. The Fosse Dionne is a “small cave” but a jewel. You never get bored of it and each dive is a privilege, a great journey deep in to the Earth.
This is just the beginning of the story. More pictures, videos, the survey and maybe some exploration will complete what has already been accomplished, and I will be very happy to share all these with you.
Pierre Eric
20th May 2019
14 Rue de la Fosse Dionne, 89700 Tonnerre, France 
