Blue Creek Resurgence

By Paul Berry

Diving the Cumberland

Diving the Cumberland

In New Zealand’s South Island region of Nelson the river running underneath Mt Owen has carved its way through the karst limestone and quartz laden granite to erupt from its base forming the Blue Creek resurgence.

The Nelson region is stunning! Surrounded by mountains clad in native forest. Waterfalls and aerated rapids cascade down the mountain slopes, running over moss covered rocks, sustaining the moisture laden flora. The native bird population is amazing, blue ducks were paddling in the river’s pools while a beautiful black, white crested South Island robin shared our lunch and generally serenaded us with its beautiful song. We were on an expedition to explore the resurgence. Our team comprised myself, Australian Chris Ross and Tony Smith. The resurgence cave entrance is extremely remote and entailed a phenomenal logistical effort just to get our equipment in.

Four-wheel drives were utilised to negotiate the seemingly endless metal roads, plagued with ruts and hidden ‘airborne fords’ as we made our way towards the head of the valley.

We made camp by the riverbed in a small clearing just big enough for a tent/trailer/4WD. We then deployed our trusty three wheeler motorbike with custom trailer (especially fabricated for the project by Eric Simmons and Johnny Little) to tow our gear as far as we could up the narrow Department of Conservation (DoC) track. Then we had to down size to a hand cart!

The trek entailed rappelling deco and stage cylinders along with bags of dive gear and all manner of paraphernalia down steep cliff faces, negotiating slippery/unstable riverbeds and finally climbing the last boulder choke to the cave entrance with me wearing my twin set and Chris his shiny new Halcyon RB80 rebreather.

Needless to say by the end of the day’s labours we were very excited about our first dives…so we decided a twilight exploratory dive was in order.

Gearing up in the small entrance pool we discussed our comprehensive dive plan and did our pre-dive system checks.

We utilized Global Underwater Explorers (GUE) Cave 2 level techniques to plan gas use from side slung cylinders for our bottom stages for the majority of our exploration dives, leaving our back mounted cylinder gas reserves for emergencies. All dives used GUE standardised gases.

I was to lead the dive, laying a primary line down to the determined 42 metre tie off point.

The granite/limestone tunnel is worn smooth from the relentless blasting of fingernail sized pebbles of predominately granite and pure white quartz. During heavy rains the volume of water causes a ‘rooster tail’ at the cave entrance which is why we paid close attention to the weather.

It had not rained for three weeks so conditions were perfect! We quickly moved down the 45 degree slope to depth, clipping off our deco stages to the line 100% Oxygen at 6m and 50% at 21m.

For quite some distance the ceiling and gravel floor nearly met, leaving just enough room for us to squeeze through. There’s nothing like good old ‘titties and tanks’ to get you going!

In places we would have our chests up to 10cm deep in the gravel with our cylinders scraping the ceiling which then caused the gravel to spontaneously avalanche downward from behind, threatening to potentially wedge us in tight against the ceiling!

Where it was difficult to maintain forward movement due to no handholds on the smoothed ceiling, or by plunging our hands into the unstable gravel, we reverted to an old cavers trick of walking our fins on the ceiling to propel us forward…good old rubber jetfins…ever faithful, fitted with Halcyon stainless springheels.

We hit depth, plus a nippy 6oC. We soon reached our planned bottom time of 20 minutes and my turnaround stage pressure of half plus 15bar. Chris’s RB80 was running on the smell of an oily rag compared to me on open circuit. He would use an estimated seventh of the gas I would, even though we were breathing at the same rate and volume.

Our ascent went as planned. At our deco stops it was getting more than a little chilly in the 7oC surface water temperature. I was shivering near the end even in my new DUI 400 gram Thinsulate undergarment with Argon suit inflation.

Chris’s hands were freezing in his three finger mitts…whereas my hands were nice and warm in my Nordic Blue dry gloves.

The look on both our faces at the surface in the near dark was priceless; here we were in the middle of nowhere fulfilling our dreams – we were two very happy divers.

Tomorrow promised us a virgin cave and wide open passage. Tony, our fantastic surface support had sorted out the camp site during our dive. We had a bite to eat then hit the sleeping bags. A night under the stars in the middle of the wilderness, fantastic! The next morning saw us up bright and early amping to get in the water. One of the challenges would be if Chris and his rebreather would fit through the restriction at 60 metres.

Today was a double bottom stage dive for me and was Chris’s turn to lead the dive. On descent Chris took an interesting looking side route which closed right down to a point where he just couldn’t quite get through the end restriction. So we simply reverse frogged kicked upward at a 45 degree angle for six metres in single file then slid sideways into another route downward…great stuff and made us appreciate the DIR skills (Doing it Right) we have both learned as it required a technically proficient reverse frog and impeccable buoyancy, especially with two bottom stages clipped on.

Once we reached my reel left from the previous day I took over and finished laying the remaining line. Chris then took the lead heading into the wild blue yonder, laying line up to and through the 60 metres restriction, which he ever so gracefully wiggled through with millimetres to spare with the breather on. Awesome, this meant we had game on!

We achieved 66.5m when we reached our 20 minute planned outward bound time limit.

Run time for this dive was 77 minutes.

Our final dive for the week has us again hitting 66.5m and toughing out a 100 minute run time in the glacial conditions. This time allowed us to just ‘take the end of the line’ but not extending it more than a few metres. While Chris tied off his reel as my turnaround gas pressure point was reached, I just managed to stick my nose into a virgin passage which ended in a direct line of sight within a round bowl shaped room, which carried on left or right?

You will just have to wait until our next project together to find out where it goes on from here…

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