Return to the Dam Bypass

Jim outside the Wild Mare with low water levels

After several months away from Spain Jim and I could take the suspense no longer. We returned to Matienzo, our goal being to find where the water flows into lake Buttermere in the Toca la Vaca system. We know it probably enters between the Whitworth series and the upstream end of lake Buttermere but the exact route in is still a mystery. If we are right we have narrowed the search down to only 25 meters of sumped passage.

The week before coming away I had been off sick from work and things were not improved by the ferry crossing of the Bay of Biscay. Perhaps the best that can be said of the crossing was that it gave me ample opportunity to get things out of my system; an opportunity I took full advantage of, it was not a pleasant crossing.

Sunday started with us worrying about food, we had brought very little and health issues forced a slow start. The time difference and the clocks changing didn’t help us either so we ended up with a visit to the supermarket followed by an optimistically long line preparation session and social calls.

Looking out of our flat towards the hills that the cave is the other side of those (roughly).
Looking out of our flat towards the hills that the cave is the other side of those (roughly).

Monday started at a reasonable time but overnight rain dulled enthusiasm and slowed the pace. The whole area had seen more rain than was needed in the run-up to our visit so we knew the cave would be wet. Once the river, visible from the flat, had dropped in level from the overnight rise we headed off to the cave. Our plan was for a short trip to carry kit in and put a ladder into the breakthrough window. Jim took on the latter job and completed it in good time despite the high water conditions and very poor visibility in the sump. I made an easy (recovery) day of things by helping Jim with kit before moving most of mine into the cave while he was sorting out the ladder.

Jim outside the Wild Mare with low water levels
Jim outside the Wild Mare with low water levels

First thing on Tuesday we were unable to see the river from the flat so we knew that the water levels had dropped further. At the cave the water level had dropped considerably so we moved two more cylinders in to the dive base this side of the duck before the rock bridge. Having the dive base nearer to the sump of the wild eels is preferable but the risk of having our kit cut off by a rise in water level is too high. After kitting up we headed off upstream, through the duck, over the rock bridge and eventually arrived at the sump. (On the way flow was visible from the inlet on the right but most of the flow seemed to be coming from the wild eels sump ahead.) Visibility in the sump had improved considerably from the previous day and the water level at the far end had dropped by about 60 cm; some 36 hours after the rainfall. We climbed up through the breakthrough window and moved Jim’s kit down to the water in AGM bypass from where he dived off to inspect the lines upstream. Upon returning he reported that all was well with the lines and that the visibility had not improved until the water from upper Whitworth was encountered. This water flowing over the cascade was cleared and appeared to be colder than the water in downstream Whitworth. Unfortunately the visibility around the dam bypass area was still too poor to see where the murky water was flowing in. On the return journey the water levels throughout then cave had dropped further and the inlet in Wild Mare was much more noticeable.

Outside the cave after Tuesday's trip
Outside the cave after Tuesday’s trip

Series - Matienzo Caving

  1. Exploring Spain
  2. The rain in Spain…
  3. Using the back entrance
  4. A Wild Mare kicks out
  5. Whitworth Upstream
  6. (Not Really) Making New Ground
  7. Return to the Dam Bypass
  8. The Dam Water
  9. Matienzo epilogue
  10. Matienzo July/August 2013, Pt 1
  11. Matienzo July/August 2013, Pt 2
  12. Matienzo July/August 2013, Pt 3

2 thoughts on “Return to the Dam Bypass”

Leave a Reply

Your email address will not be published. Required fields are marked *