Dec 172014

Empty reel returned!

About the cave

Growling Swallet is a major sink in the Junee Florentine karst area in Tasmania. Water from the river that rushes into the cave entrance has been dye traced to emerge in the Junee resurgence, several miles away. Unlike other caves in the area Growling has an entrance that doesn’t require ropes or SRT, just a few very sketchy free climbs. The name describes the noise of the river rushing in when in flood, and as you would expect caving is only possible in low water conditions.

The way through the cave alternates between following the water and climbing up and over it. From a caving perspective this means that even on the way in (usually downhill) there are several large ups to be climbed. On the other hand this provides some downhill on the way out…

Watching and waiting

About the trip

The intention for the weekend was to carry one set of dive gear, plus a suit for a second diver to the terminal downstream sump. Dreamtime sump is where both water from the entrance and water from a terminal branch disappear underground. The water here is next seen in Niggly Cave before eventually resurfacing in Junee. The estimated distance to the mapped passage in Niggly is only a few hundred metres. More interestingly, the data suggests that a major branch of water should flow into this gap between the two known systems. The sump was dived years ago without success, but with sidemounts and improved equipment and techniques we were somewhat optimistic about making progress.

About the dive

After nearly 5 hours of hauling packs through the cave, we lined up on the bank and watched Steve put his dive gear on. The plan was for him to dive first using the two 7L tanks. Andreas was then going to dive second with the remains of the gas to see if further progress could be made. He crawled off into the water and after watching for about 5 minutes it became obvious this was going to take a while. 35 minutes later he appeared, with survey distances and directions memorised. After a quick transcription onto paper we got the full story.

The sump continues 50m or more through a wide and low silty flattener, requiring a bit of wriggling to get through. It then surfaces briefly into an airbell with no “dry” land, but remains shallow enough that you could stand up. Following this the dive heads back into the water and the passage opens up into swimmable territory. All of this was shallow at less than 3m depth. Despite the feeling that we might get somewhere, I definitely had the view that carrying in the full reel of knotted line was slightly delusional. As it turned out, Steve ran out of line well before approaching his gas limits.

The first photo here is the triumphant return, following survey transcription. The reel has a bit of line left on it due to a lack of suitable tie-offs on the silty floor at the further point reached. And the second photo here is the chorus line of cavers, finding out what happened underwater. Sump diving is not generally a spectator sport so a successful return with news of ongoing exploration is always good news.

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