Leclused
Active member
This is the story of the elimination of Siphon 2/3 in ?Chantoir de Fagnoules ? Belgium?.
When I joined the club SC Avalon in 2005 they were just starting with the elimination of the S2/S3 in the Fagnoules. The cave was then a recent discovery of Avalon but they were stopped at a S2 downstream. This S2 was dived by M Pauwels en J Petit and the two divers discovered a large extension of the cave after they also dived a S3 that followed the S2 directly. This extension had large galleries, a river and even an 8m waterfall. They were eventually stopped by an S5 some 500m further in the cave. So no need to tell that all club members were eager to see this part of the cave too. And in order to help the divers at the S5 we needed to be able to go through the S2/S3 without diving.
So Paul made a masterplan to pump the S2/S3 empty by pumping the water further downstream beyond S2/s3. In a nutshell here is how we did it:
- 200m uptstream of the S2/S3 a small dam was build and the river was captured and channeled through a firehose (320mm diameter).
- The divers pulled the 320mm firehose through the S2/S3 and the river that was running through the firehose was dumped in the S4
- At the S2/S3 a smaller firehose was used to pump the water that was still standing in the S2/S3 upstream and then into the firehose of 320mm at an Y-junction with a valve.
Installing and finetuning this setup took us already 3 months to complete. But now we were able to pass the sump dry and visit the cave post siphon. Months went by and the sump was pumped several times. The part beyond was explored and surveyed and we were able to help the divers at the S5. This S5 was dived and again the divers were stopped by an S6 and later by an S7. The S7 was not diveable but there was a small dry passage passing the S7. This passage required some heavy desobstruction techniques which the divers couldn?t do.
In the meanwhile we were already started with the elimination of the S2/S3 siphon by pulling of the roof of the S2/S3. This was a huge work. The S2 was 13m long and went to -3m. During 2.5 years countless trips (almost every 2 weeks) were undertaken and step by step we pulled of the roof using heavy drills with a drill bit of 1m long to drill the holes. Every time we went down the power engine used liters of fuel outside the cave to provide us of enough power to drill and pump.
Usage of a heavy powerdrill to drill 1m long holes.
But then the day 21/7/2006 came and we arrived at the S2 where we felt an airflow over the water. The siphon was no more and Paul and myself went through the S2/S3 without diving. A big relief for us and we were happy to have completed this tremendous task.
But this was not the end of course. We repeated the same method to eliminate the S5 and S6 so that we could tackle the small passage at the S7 to see what was beyond the S7. But that is another part of the Fagnoules Saga. Beyond the S7 we discovered again several hundred meters of cave leading to an S9. The cave was connected with another nearby discovery ?Chantoir de Buc? of us and currently the cave is almost 3km long. A trip in the system Fagnoules-Buc is nowdays a wet and sporting trip. Exploration is still going on but is going slow nowdays, other discoveries in Belgium are keeping us busy.
The river post S2/S3 in high water conditions.
The complete Saga (so far and in dutch) can be read here :http://www.scavalon.be/avalonnl/discov/chantoir_des_fagnoules.htm
I wrote this report to encourage other cavers to write trip reports / project descriptions. I know writing is not always easy, but if you start doing it you will see it is really fun to do. I'm not a British caver so if this report is not counting for the competition then it's not a problem for me and if there are any grammar faults in it. Sorry for that
Text : Dagobert L?Ecluse (Sc Avalon)
Photos : Paul de Bie (Sc Avalon)
When I joined the club SC Avalon in 2005 they were just starting with the elimination of the S2/S3 in the Fagnoules. The cave was then a recent discovery of Avalon but they were stopped at a S2 downstream. This S2 was dived by M Pauwels en J Petit and the two divers discovered a large extension of the cave after they also dived a S3 that followed the S2 directly. This extension had large galleries, a river and even an 8m waterfall. They were eventually stopped by an S5 some 500m further in the cave. So no need to tell that all club members were eager to see this part of the cave too. And in order to help the divers at the S5 we needed to be able to go through the S2/S3 without diving.
So Paul made a masterplan to pump the S2/S3 empty by pumping the water further downstream beyond S2/s3. In a nutshell here is how we did it:
- 200m uptstream of the S2/S3 a small dam was build and the river was captured and channeled through a firehose (320mm diameter).
- The divers pulled the 320mm firehose through the S2/S3 and the river that was running through the firehose was dumped in the S4
- At the S2/S3 a smaller firehose was used to pump the water that was still standing in the S2/S3 upstream and then into the firehose of 320mm at an Y-junction with a valve.
Installing and finetuning this setup took us already 3 months to complete. But now we were able to pass the sump dry and visit the cave post siphon. Months went by and the sump was pumped several times. The part beyond was explored and surveyed and we were able to help the divers at the S5. This S5 was dived and again the divers were stopped by an S6 and later by an S7. The S7 was not diveable but there was a small dry passage passing the S7. This passage required some heavy desobstruction techniques which the divers couldn?t do.
In the meanwhile we were already started with the elimination of the S2/S3 siphon by pulling of the roof of the S2/S3. This was a huge work. The S2 was 13m long and went to -3m. During 2.5 years countless trips (almost every 2 weeks) were undertaken and step by step we pulled of the roof using heavy drills with a drill bit of 1m long to drill the holes. Every time we went down the power engine used liters of fuel outside the cave to provide us of enough power to drill and pump.
Usage of a heavy powerdrill to drill 1m long holes.
But then the day 21/7/2006 came and we arrived at the S2 where we felt an airflow over the water. The siphon was no more and Paul and myself went through the S2/S3 without diving. A big relief for us and we were happy to have completed this tremendous task.
But this was not the end of course. We repeated the same method to eliminate the S5 and S6 so that we could tackle the small passage at the S7 to see what was beyond the S7. But that is another part of the Fagnoules Saga. Beyond the S7 we discovered again several hundred meters of cave leading to an S9. The cave was connected with another nearby discovery ?Chantoir de Buc? of us and currently the cave is almost 3km long. A trip in the system Fagnoules-Buc is nowdays a wet and sporting trip. Exploration is still going on but is going slow nowdays, other discoveries in Belgium are keeping us busy.
The river post S2/S3 in high water conditions.
The complete Saga (so far and in dutch) can be read here :http://www.scavalon.be/avalonnl/discov/chantoir_des_fagnoules.htm
I wrote this report to encourage other cavers to write trip reports / project descriptions. I know writing is not always easy, but if you start doing it you will see it is really fun to do. I'm not a British caver so if this report is not counting for the competition then it's not a problem for me and if there are any grammar faults in it. Sorry for that
Text : Dagobert L?Ecluse (Sc Avalon)
Photos : Paul de Bie (Sc Avalon)