Volume 42 Number 2 Article 8
Grotte de Bournillon
29 August 2005
Samuel, Julian and Carl Carradice, and Andy Whitney
On the day after our visit to Gour Fumant we experienced "real" Vercors rain! Fortunately this only lasted one day, after which the weather steadily improved (with one exception that Andy may cover in another article). However, it was sufficient to result in some spectacular flooding at the various resurgence caves, and our visit to Bournillon, which can discharge up to 80m3 per second, was postponed for several days.
The 80m high entrance porch of Bournillon is the largest in France. I had seen this before on my previous visit to the Vercors, but had not entered the cave beyond. It is situated at the base of a cirque of massive cliffs on the south side of the Gorges de là Bourne, almost opposite the Choranche show-caves.
We approached the hydro-electric station (fed from the cave) on the road from Choranche village, but were stopped a few hundred metres early by a locked gate. A notice warned of impending death from "chutes of stones" and prohibited all vehicular and pedestrian access. Naturally, we chose not to understand the French text, got changed, and followed the well-worn path around the edge of the fence. The walk to the cave takes about 30 minutes, beginning with a steep but brief climb, then a traverse among trees and patches of scree, and a section below an overhanging cliff before turning right at the head the cirque. The entrance is so big that you are not quite sure when you are inside it.
Samuel in Bournillon entrance
Normally, the stream (or river) emerges over a cascade into a lake. On this day the stream was dry, but the lake remained, and was deep, and we didn't fancy the traverse around the walls. The alternative is to ascend a massive boulder field to reach a ledge overlooking the passage beyond the lake. We soon found the way down, for which the guidebook suggests a hand-line for novices - it didn't look particularly stable!
The passage was completely different from my expectations - I had always imaged a clean-washed streamway. Instead, one is faced with continuous boulder-hopping, with the stream never seen but occasionally heard far below. Clearly, the water rises to this level in times of flood as the rocks were scalloped and covered in an unusual thin black slime.
After about 250m an area of large formations is reached called the Village Négre, and after another 300m the stream is reached at a point that sumps quickly when levels rise. There's a lot of cave beyond this point, but Julian and Carl had already turned back as this was intended to be a short trip, so Andy and I decided to follow.
Samuel at VillageNégre
Before leaving, Andy and I also had a quick look in the second entrance just outside the main porch. Again, this ascends a boulder pile in a colossal phreatic passage that defeated all attempts at a photographic record. At the top, the dimensions dwindle to something more like Ease Gill upper level, and then a crawl connects the to main cave near the Village Négre.
Bournillon is an amazing place, even for a short "tourist" trip. In many respects, I regret not having seen it in full flood - it must be awesome!
(Photos by AW)