Réseau Christian Gathier

The excellent through trip in the Réseau Christian Gathier between the Trou des Anciens and the Scialet du Brudour was undertaken on the first Monday of the CPC Vercors meet (June 29th), by Mike Bottomley, Tom Baker, and myself.  It comprises about 4km of very varied progress, including some 2km of stream passage.  One descends to -327m from the Trou des Anciens entrance, ascending +112m again to exit the Scialet du Brudour.  An excellent description is available in Spéléo 50 (April 2005) pp17-21.  A survey accompanies this article, and the whole thing can – for the time being at least – be found online in PDF format by searching for traversee-anciens.pdf.  As of August 2023, it seems this article is no longer on the internet: contact me if you want a copy (PDF).

The Trou des Anciens starts off with the 48m Puits des Jouisseuses past a rather dodgy-looking boulder slope at the top, held back by faith, and a big piece of netting.  Then down through a boulder choke past a collection of train signs obviously acquired by rather dubious means!  Following a 6m drop, the next 100m are in an unexpectedly awkward narrow twisting rift with the peculiar name of the Méandre de la Gentille Fée.  This arrives at the bottom of a 4m climb up into the much grander Galerie Père et Fils.  Rapid progess can then be made to the remaining pitches (20m, 16m, 6m) down to the junction with the streamway – la riviére de Montué.  All the pitches and traverses up to this point were rigged.

The Montué stream passage is excellent varied going, and in two places it is necessary to ascend fixed ropes into fossil passages to avoid sumps.  Just to give an idea the cascades and pitches in this section are 7m, +9m, 10m, 4m, 5m, +4m, 3m, 7m, +9m, 3m, 7m, 5m, 22m, and another 22m (+ indicates an up pitch with fixed rope).  Actually – I'm not sure if we didn't lose a cascade or two somewhere in this lot!  There are also rigged traverses above pools.  All the down pitches are rigged with traverse lines to easily accessible pull-through points.  None of the pitches in the streamway were rigged.  Two striking images stick in my memory.  The first is a stunning 100m section of canyon streamway with parallel walls stretching up to infinity.  The second is the spectacular still-pristine-white formations.  The final 22m pitch drops into the Salle de la Cascade, where I had been twice before (in 1999 with Karen and Andy, and in 2008 with Carmen).  From here large fossil galleries lead to an obscure route up through a boulder choke into the massive 120m long Salle des Ténébres.  The exit from this chamber leads to the Passage Clé and the beautiful rivière de Bournette.  At the end of this a +10m pitch gains the two Métros, followed by +7m and +5m pitches into rather grottier passages and crawls to the Scialet du Brudour, where we exited after about 6½ hours underground.  All the interior up pitches have fixed ropes, but the 10m (15m ?) entrance pitch requires rigging (20m rope, 3-4 spits).  As of August 2023, an initial Y-hang off P-bolts drops to a roomy ledge at -6m, with a second Y-hang / single-bolt rebelay / deviation according to taste, for the final drop.  Allow 30m of rope if starting from the obvious tree on the surface back from the entrance.

The preceeding day I had spent a frustrating couple of hours looking for the Trou des Anciens, misled by inaccurate co-ordinates on the survey accompanying the Spéléo article.  The written description is more reliable.  The signs in the entrances warning of pollution in the rivière de Bournette are out-of-date and can be ignored.  The signs warning of the risk of flooding in bad weather should be taken seriously – see the Spéléo article! 

For the record, the correct entrance co-ordinates for GPS are:

UTM (WGS84) 31T 682686 4975717  Trou des Anciens

UTM (WGS84) 31T 683304 4977237  Scialet du Brudour

In the Lambert III system:

x = 835,10 y = 3294,41 z = 1468m  Trou des Anciens

x = 835,70 y = 3295,94 z = 1226m  Scialet du Brudour

As gear we took a 50m length of 9mm plus 25m spare, plus a few maillons and a couple of slings just in case.  It is useful to have the long rope as it means that all the pitches can be done on one rope. 

Here is a system to pull down a short pitch on a long rope, where short means less than a third of the rope length.  It assumes that the rope has been packed in a tacklebag with a knot at the bottom end.  It also assumes the pull-through point is a backed-up anchor.

1. Feed the top end of the rope through the anchor and tie a knot in the end.

2. Feed through enough rope so that you are reasonably sure it has reached the bottom (either checking visually, or measuring armlengths approximately) – call this the short side of the rope.

3. Tie a figure-of-8 (or alpine butterfly) in the other half of the rope not fed through the anchor and clip to the anchor with a karabiner – call this the long side of the rope.  At this point its safe to abseil down either side except we don't know for sure yet that the short side reaches the bottom.

4. The first person therefore abseils down the long side of the rope feeding it out of the bag.

5. This person can then check that the short side of the rope genuinely reaches the bottom – if not, it is necessary to adjust the lengths.

6. The last person unclips the karabiner from the anchor and clips it into the short side of the rope, then abseils down the short side of the rope.  If sufficiently paranoid a person at the bottom can tie into the short side to safeguard against the person at the top mistakenly abseiling on the long side.

7. Take the knot out of the short side of the rope – this is absolutely essential to avoid embarrassment (!) – and pull the rope down; repack into the bag.

The advantage of this method is that only just enough rope to double the pitch is ever taken out of the bag. It was perfected on a 2005 Diau pull-through trip with Carmen and Pete Smith.

Adapted from CPC Record 96, 27-28 (Oct 2009). 

Copyright © (2009) Patrick B Warren and Craven Pothole Club Ltd.