Vadose – pheratic – what on earth has that got to do with caving?
As I neared the pit the tunnel became narrow and tight as would be expected with water running in a vadose channel. Underground the water is either running above the water table or beneath – resulting in either vadose or pheratic tunnels.
A vadose tunnel such as this one tends to be deep and narrow while a tunnel formed beneath the water table is tubular or elliptical in crossection. With free flowing water – above the water table – most of the wear is at the bottom of the tunnel – both from corrosion and abrasion. The greater the bedload in the river the more the abrasive effect of the running water. Corrosion – chemical erosion is dependant upon many things – the temperature and carbonic acid concentration are the factors that most readily spring to mind.
Another unusual feature of the tunnels that preceed a pit is that they often tend to show increased wear as the lip of the drop is approached – this is the case here as well. Just beyond the water spills over about a 15 foot drop, the tunnel curving under itself and according to those who have descended – gets very wet and muddy.
I looked over the edge and the skinny little rope that someone had looped over a protrusion and opted for a later descent with a rope of my own choosing. I recall my first visit to Dewdney’s Cave (Another Ontario cave) some 15 years ago. I was negotiating “Ongley’s Hole” and using a 1 inch rope that I had not installed. The rope snapped and I fell a short distance landing on my backpack full of photographic equipment.
Hi there, I am interested in exploring dewdney’s cave in May or June and will be travelling there from ottawa. I was wondering if there are any difficulties there somone should be aware of before exploring there or certain times of year which are more dangerous than others.
any information would be greatly appreciated
-James
James – It is private Property.Make sure you have permission. It also not acessible like it once was. And to top it all off,its right beside a hunting camp. That means guys with guns looking for moving objects. PERMISSION!!!!!