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Système de Bretaye - Bomal (No. 4) 


Province: Luxembourg
Locality:  Bomal (Durbuy)

B0 (resurgence):              X 233,410   Y 117,954   Z 145,0 m
B1: (Fosse Crahay)         X 233,496   Y 117,971   Z 174,6 m
B5: (Capture de l'Aisne)  X 233,780   Y 118,203   Z 148,9 m

Map: 49/5-6 & 55/1-2

In the village of Bomal-sur-Ourthe, take direction Juzaine or Aisne.  Pass the tiny village of Juzaine, traverse bridge over river Aisne.  Park the car after 1,5 kilometres at the right of the road, just past an isolated house at the border of the road.  The upper entrance is located at the opposite bank of the river Aisne, 100 m upstream of the parking.
HISTORY: Making the Ultimate Junction
SC Avalon started working in the resurgence of the cave in 1991.  Quickly work shifted towards a sink in the woods (Fosse Crahay) that gave access to an underground river. Then, at the other side of the mountain, an active sinkhole (Capture de l'Aisne) was opened and lead to the discovery of a fine streamway that was later linked to the Fosse Crahay. In 1993 the cave was linked to the resurgence, thus permitting a complete traverse from sink to resurgence. It took about 115 days of labour, spread over a period of 3 years, to reveal this big cavesystem that traversed the whole mountain from one side to the other.
The cave is situated on private land.  Agreements with the landowner have been made.  Access is permitted but controlled by SC Avalon.  If you want to visit the cave, then write to SC Avalon, Jan De Bodtlaan 59, B2650  EDEGEM, BELGIUM one month before your visit. SC Avalon will inform the landowner of your visit and give you a written permission.
It only makes sense to ask for permissions for visits in the months June to October (dry season)!  In all other months, water levels are so high that most low passages are sumped.  You have to follow access regulations very strictly: only 1 team can visit the cave per weekend.  NO CARBIDE lighting, max. 6 cavers etc..

Download hier het toegangsreglement (PDF-formaat) in het Nederlands. 

T??hargez ici le r?lement d'acc? en Fran?is (format PDF)

Length: 1715m,  Depth: 30 m
One thing is sure: this is one of the wettest and most exciting caves in the country.  You'll need a lot of guts to do it!
The cave is entered by the upstream entrance, Capture de l'Aisne.  Some 100 m of often narrow galleries lead to a big room (Salle de la Rivière Perdu).  Unfortunately, this part of the cave that was a few years ago a splendid river passage, is now bone-dry due to bulldozer-works in the riverbed that have sealed off one of the sinkholes...
Anyway, in this big room, a passage between boulders (very selective squeeze!) leads to Salle Annette, then to Salle des Rolling Stones where one has to climb down a muddy pitch that leads to a low and wet water-filled gallery (Korte Leemstraat). Boyau Harakiri After 20 m, a 7 m long and only 50 cm diametre gallery, filled for 2/3 with water has to be taken: Boyau Harakiri.  One arrives in a big gallery where another and more important river flows.  Going upstream and immediately taking a passage at the left, between boulders, one can visit the 300 m long "Rivière Inconnue"-series.   The logical way however is downstream.  The gallery quickly gets very large (10 x 10 m): you are in the "Galerie Avalon I"; well decorated and impressive.  Some 100 m further, the river disappears into a low passage "Passage du President" which is in fact a 4 m long duck with only 5 cm of airspace.  After this exciting obstacle, one is in the "Galerie Avalon II", still very large but extremely muddy.  After 75 m a new and very long duck (Siphon de la Jonction) has to be taken: 10 m long, 5 cm of air.  Luckily, 4 airbells make life a lot easier. The big Galerie Avalon I
One reaches "Galerie Avalon III", still 8 m wide.  After 50 m, follow the river that disappears at the right in another short duck, Passage Blubs.  Then a beautiful phreatic passage (La Ligne Droite), filled chest-deep with water, leads to a section were the river is very large (5 m) and the water deep.  Then one arrives in "Salle du Rêve", where one leaves the river and searches a rather complex passage leading to a big room "Salle du Chaos".  In the lowest part of the room, one can find the river again.  Here a duck has to be free-dived (Passage des Pieds Humides): it is 2 m long; water is deep but airspace unsufficient to breathe...  15 m further one takes the "Jonction Ultime", a 5 m long rift that was enlarged after months of works and that linked the cave to the resurgence.  One arrives in a 5x5 m room (Salle de l'Ange Gardien).  The rest of the trip is rather difficult (lot's of squeezes, wet passages, narrow) and has nothing of the splendor of the big galleries in the middle section of the cave. Finally exit is made through a small opening, only 5 metres away from the resurgence, after an underground trip of +/- 620 m.

No ropes are required.  All SRT-gear that you carry (e.g. sit-harness) will only bother you in the squuezes.
This is a must for every water-loving caver!  Of course, a wetsuit is the only appropriate clothing to wear. The through-trip takes about 2,5 to 3 hours.   Water levels are less high than they used to be, but this also depends on the weather conditions of course. All ducks are best taken feet first while you lie at the back, helmet in the hand, and your lips and nose against the roof! Stay calm and it will go just fine.
DO NOT ENTER THIS CAVE IF WEATHER IS UNSTABLE!  If the underground riverlevel rises 5 cm; you are stuck because that is the average airspace in the ducks.  In flood conditions, water rises 300 cm... so be warned!


Link to a Picture gallery (30 picture): a virtual throughtrip of the cave.

Link to the access policy (in Dutch and French).

Link to a big article (in Dutch) about the Bretaye System.

SURVEY: Click here to see the survey


Contacteer/contact us:  SC Avalon vzw
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