19 September 2005

Report on weekend 10-11 September 2005

Within the framework of the SELAS Caving Club's ongoing project of exploration at the Dersios sinkhole in Arcadia, an expedition was planned for 10-11 September with the following aims:

Ι. Survey from the second sidebranch to the large chamber / junction at -151m (green on chart)
ΙΙ. Survey from the end of the surveyed section in the sidebranch until the third sidebranch sump (in red colour)
ΙΙΙ. Survey from the large chamber / junction at -151m to the beginning of the third sidebranch sump (yellow colour)
IV. Cave dive with survey equipment in the second sump and evaluation of continuation potential. (blue colour)
V. Cave dive with survey equipment in the third sump (loop closure - the loop will be more than 1km long) (blue colour)

click on image for enlargement

So we all got to the plateau at some point on Friday evening and all four cars made their way to the cheesevault next to the entrance of Dersios. The electrification of the plateau had reached the cheesevault and we now had the added luxury of electric lighting at night. We got ready for bed intending to organize the expedition the next morning during breakfast. The aims of the weekend were well known. The survey team would also de-rig the new section, the diving team would only deal with the diving. After a good dose of omelette (with sausage and other goodies) the diving team (Nikos, Komninos and Panagiotis) set off straight for the second sump while the de-rigging team (Nontas, Maggie and myself) set off for the sidebranch a little later with Olga and Panagiotis.

Reaching the point a little before the scree slope linking the two sumps (point 0504 on the survey) we found the water very much higher than on all previous visits coming after the original emptying of the sump. The water was up to chest height and the low passage to the scree chamber was only a little more than 40cm from water to ceiling. We made the decision to go for it - seeing as we would be getting wet anyway that day and I got into the water on my back to get through. I made it through and up the scree through an even smaller gap and waited for the others. Approaching the chamber from which the passageway began we realised that we had lost the passageway in the five weeks since the last visit - it had sunk once again under the water.

In mythology, in Hades, the Danaids perpetually filled a leaky pot with water which never filled... in the Dersios sinkhole this year, we have been perpetually emptying sumps which refuse to remain empty. Next year will be different - we will approach the whole sump thing differently.

We stayed inside for a little longer - Maggie took Panagiotis and Olga round the cyclical route through the sidebranches and then a little deeper, while I made my way out into the sun with Nontas. Maggie's team found Panagiotis on the way down, the first sump was full as well and needed a dive to get through. Nikos and Komninos had gone through and deeper to make the dive in the second sump.

While we were outside with Nontas, two young shepherds passed, brothers with a shared flock and we got chatting with them about the area and about the sinkhole itself. The information we received was the usual mix of myths, folklore and local knowledge about the area around the sinkhole. An important piece of information is that from the beginning of the summer it had rained only once - and that for only half an hour. This shows that the sumps re-fill without rainfall - something to keep in mind in the future.

Nontas talks to the shepherd while still in the wet and cold neoprene outfit - commitment to information collection requires local info to be gathered to come before personal comfort. In the background, the cheesevault.

We began to prepare snacks and waited for the diving team to come out so we could begin to make the pasta. At some point Theodossis came as well and brought wine and set the fireplace alight. When the diving team came, we put the food on and listened to their news.

Theodossis gets the fireplace started

As we had been told - the boys passed the first sump by diving - Komninos' first cave diving experience, may he have many more! - and headed straight for the second sump for Nikos to dive. Nikos dived successfully and took survey data within the sump (which is about 30m long). The data will soon be added to the rest of the cave and announced. Nikos then walked to the next sump about 150m away. He had a look inside and it seems deeper than the rest. Nikos then made his way back to the second sump taking care to look for return routes which would bypass the sump, but found none. The next goal is now to empty the second sump and dive the third to look for continuation.

Two divers

In 2003, the second sump seemed to be impossible to empty but now, with the accumulated experiences which we have gained both as individuals and as a club, it seems that it will be possible to empty the second sump despite the small but continuous influx of water.

On the second day, most of the team set off early for Athens so I was left with Nontas and Panagiotis to go do some rescue work in the cave. First priority was to get the 120m of hosepipe out of the sidebranch so we didn't lose it when the sumps get completely filled again. Next, there was a need to re-rig the pitch after the lake in the chamber with the stalagmite. As we set off for the entrance we found some friends of Thoedossis who had come to join us from "Spena". We were happy to have the opportunity to share our descent with Yiannis and Makis, both active members of "Speleology of Nafplio".

We went in and re-rigged the worn rope and went down to the now completely empty first sump to close the taps on the hosepipe to ensure the hosepipe didn't fill up with air again. The kids from Argos left for outside and we gathered up the hosepipe from the sidebranch and hid it away above ground in a place where the winter waters shouldn't reach it.

So what's left now? Well, we need to de-rig the whole cave before the winter starts and that includes getting all the rope out of the sidebranch - something which will need another cave-dive.

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