Discovering new depths in cave diving, New Zealand

A small group of super adventurous divers are mapping ever more of New Zealand’s underground cave systems. Their explorations are linking up cave systems hitherto at a dead end, using the full range of caving and diving technology and skills available while developing new approaches along the way.

Exploring dry and underwater caves in New Zealand is hard work! It’s physically and mentally challenging. Dragging cylinders and dive equipment sometimes through quite small sections of a dry cave just to jump in a pool of water to see if the cave continues under- water is not for everyone, including many cave divers.

But for some of us, that challenge is the very reason we keep on exploring. To overcome the challenges, and be the very first people to see and map a new passage underground or underwater is incredibly satisfying.

The WEKA (Wet Exploration of Karst Areas!) team of which I’m a member, reside in different parts of New Zealand and get together whenever we can to share our enthusiasm for exploration.

Over the last 10 years we’ve explored and mapped a significant amount of underwater cave passage in various parts of New Zealand. However this article focuses on our recent discoveries in the Marlborough/ Tasman district and the West Coast, then I’ll discuss some of the attributes you need if you yourself were thinking of beginning to explore cave systems underwater.

Marlborough/Tasman

The Spitalls System lies in the Takaka Valley Karst, a network of dry and underwater caves accessed on land owned by Rob Davies and Michele Allison. Rob and Michelle are very experienced dry cavers from Wales who moved here about 10 years ago and who purchased the land in Takaka because of
the caving opportunities on offer!

The Spitalls is prone to flooding so can only be explored in the right conditions. Rob and Michelle spend their summers exploring dry sections and
call in cave divers for the submerged areas.

The original cave diving explorers here were Martyn Farr, a renowned Welsh cave diver, and Kieran Mckay, a kiwi caving and cave diving legend.

In 2019, Tom Crisp and myself made an important contribution by connecting two of the caves in the Spitalls System - Cottage Cave and Totara Cave - in a two hour long dive. This link meant the Spitalls system then became over 12 km of passage, placing it the 10th longest cave in New Zealand.

The Spitalls System was also the location of the first Cave Diving SAREX (Search and Rescue Exercise) in November 2019, a highly successful event run by Dr Richard Harris. Richard was involved in the Thai Cave Rescue of 2018 and the experience we gained from him during the SAREX was invaluable.

Riuwaka

A half hour drive from the Spitalls and near Motueka is the Riuwaka system. Kieran Mckay and myself have made two trips here in the last six months, exploring further into this spectacular cave system than any previous expeditions.

The Riuwaka consists of a series of sumps and dry cave passages so climbing, rope rigging and dry caving experience is needed as well as cave diving skills. This is technically and physically a very challenging cave.

However the possibility we might be able to connect the Riuwaka system to the MiddleEarth/ Greenlink system, which lies approximately one km to
the northwest, is an enticement to further exploration. If connected this system of caves would be the second largest in New Zealand.

Pearse Resurgence

No update of the Malborough/ Tasman area would be complete without mentioning the Pearse Resurgence!
The Pearse Resurgence offers the mother of all cave dives. At the base of Mt Arthur water from the Nettlebed cave system surges out of the limestone to form the head of the Pearse River.

In February 2020, Australians Dr Richard Harris and Dr Craig Challen dived to 245 metres depth in the Pearse using twin rebreathers – the dive lasted 17 hours (of which 16 hours was decompression).

The Pearse was still descending at the deepest point they reached. Richard and Craig were planning another expedition this year but Covid 19 postponed the trip. The WEKA team are proud to have assisted Richard and Craig on their last few trips there.

The Pearse is a cave dive requiring very specific skills and experience. The use of underwater habitats, heated under-suits, underwater communication systems,
and multiple rebreathers are required for the extreme depths of this cave. So far only seven people have ventured past 150 metres and only three of these continued past 200 metres. Keen anyone?

West Coast

The West Coast has multiple cave systems, both under- water and dry. The biggest challenge exploring here is the weather. Heavy rainfall often floods these cave systems so completely that any expedi- tion planned must be prepared to lose time waiting for the weather to clear.

The Nile River near Charleston flows over a large area of West Coast limestone that has a number of caves which for the past five years have been explored by Mike Batey, Guy Bates, Tom Crisp, Kieran Mckay and myself, with Matt Coutts joining the team this year, on a the water flow to manageable levels. We were able to explore a further 600 metres or so of cave passage at depths up to 37 metres.

Kieran Mckay explored another 300 metres of passage in a cave approximately one kilometre away and we think it probably connects to DBS, but a rock fall at the furthest point in the cave blocked our way forward. In future we think we will be able to move those rocks out of the way to continue onwards.

So what attributes do you need if you’re thinking this cave diving exploration might be for you?

Obviously being trained as a cave diver is an absolute neces- sity! Cave diving involves more risk than normal recreational diving. Special procedures, training and equipment are necessary to manage the risks.

Diving experience plays a large part, not just in cave diving but also for general technical diving as well. Modern cave exploration quite often requires rebreathers, mixed gases, staged cylinders and decompression diving. Our expedition this year to the Nile River near Charleston involved dives lasting three hours and at depths up to 37 metres.

We used sidemount and back mounted rebreathers (Kiss Sidekick and JJs), Trimix gas mixes, and Diver Propulsion Vehicles (DPVs) as the flow
in the caves was too high to swim against without over exertion. The temperature of New Zealand’s water means dry suits are an absolute necessity for longer dives!

Keep an open mind. Work in a team

Just as important as experience is an open mind and the ability to work in a team. If you can look at a challenge and say: “How can we overcome this safely and efficiently?” Or “What’s the best equipment for this job?” then you are well on the way to becoming a successful cave explorer.

Being mentally and physically fit is also of course key attributes. If you aren’t able to cope with some hard work then you would quickly become a liability to yourself and team mates.

Cave diving is a very niche part of recreational diving with training to become a cave diver usually taking place overseas due to the lack of instructors and appropriate training environments locally. It requires dedication and a substantial investment of time and money to become qualified, and then experienced enough to start exploration diving.

But the satisfaction from completing a successful exploration cave dive is definitely worth it!