About the site
Olwolgin Cave is located on the Roe Plains, south of the escarpment that curves across above the Great Australian Bight. Unlike the Nullarbor Caves above the escarpment, where the water table averages 100m below the desert, on the Roe Plains the water table is only 10m under your feet. This makes for much easier access. On the other hand, there aren’t the spectacular dolines that punctuate the Nullarbor and act as great big signposts of cave formation.
Olwolgin Cave is shallow, up to 14m deep, has small, twisting passages in multilevel formation and a greenish tint to the water. From my dives here in 2010 I’d admired the massive hanging root formations. As I mentioned, I didn’t get a chance to do a dedicated photo dive to the hanging roots, but only snapped some opportunistic shots on the way through. This trip, that was about to change…
About the dive
While the 2012 expedition was focussed on pushing new passages and exploring Unnamed Cave, after we had completed a number of dives it became apparent that the restriction had moved. Whereas previously it had been relatively easy to navigate by following the rope in zero vis, it now required a 90 degree turn in two dimensions to pass through. After a little bit of gardening, we decided to leave it to settle out as required, and went for a dive in Olwolgin Cave instead.
This was a dual purpose exercise, with the first half of the dive being dedicated to video and the second half stills. The shallow depths involved gave us a two hour dive time on a set of twins and no deco to complete. After videoing the roots and the passage beyond I switched to stills. These shots were captured on our way home.
About the photo
This area of Olwolgin is known as Babylon Lake for its hanging gardens. The area above is enclosed by the cave but above the water table. Unfortunately it’s not a breathable air mix, with decomposing organic matter creating a nasty concoction. As the air chamber is completely enclosed there are no surface breezes above and the surface is glassy still. From underneath the still surface creates beautiful reflections. Photography here is about floating rather than swimming, trying not to disturb the water towards the roots or create too many ripples on the surface.
The area behind the roots contains a lower roof and the entrance to the passage we had just returned from. You can see the lights of my dive buddies, Ken and Grant, through the root mat formations. At the top of the picture, the very slight rippling of the surface has duplicated the pinpoints of light three times. In the second photo Ken has appeared around the side, trying to work out if I’m finishing taking shots yet. While the first shot is my favourite, the diver in the second provides scale and context for the whole strange scene.