Hewn through solid rock with pick, drill and the sweat of hundreds of men, this engineering feat was completed with the desire to divert the raw power of Holts Creek that flows relentlessly from the deep narrow canyon above.
A waterfall cascading into the riverbed below drains a high pool that was once blocked by an ancient dam and it is from here that the power of Holts Creek was harnessed, diverted into the tunnel and onwards on a wild rollercoaster ride through wooden pipes two kilometres down to the Otira valley below.
The pipes followed a remarkable track constructed by the tunnel contractors. It was cut across rocky cliffs, carved through vertical bush slopes, crossed deep ravines on truss bridges, and down to a powerhouse constructed at the junction of the Otira and Rolleston Rivers, directly opposite the newly opened Otira tunnel entrance.
This harnessed power of Holts Creek would spin the pelton wheels and dynamos to generate power for compressing air to drive rock drills and bore through the main divide towards Arthur’s Pass. The race to finish the Otira tunnel was on!
Reading these fascinating stories of ancient tunnels, tracks and waterfalls in 100 year old newspapers in mid Christchurch winter ignited our spirit of exploration. Lots of excited emails and conversations with Grant Prattley were had, and a mission was hatched to go and explore this forgotten piece of history. On a map the canyon above was a dark incision, deep and impenetrable with marked waterfalls of 70m and 106m. Clearly a recce was in order!
At the junction of the Rolleston River and Holts Creek, we excitedly discovered the remains of the old powerhouse, and the start of a wide 100 year old track through the undergrowth. As we climbed up the steep rugged terrain of lower Holts Creek, initial clues of human presence were evident. We found old metal grates and timber jammed under boulders. After 90 minutes the valley terminated abruptly with a spectacular barrier waterfall pouring in from the neighbouring branch. As we climbed higher to get a closer look at this we heard roaring water coming in from our right, and the true exit of Holts Creek was revealed!
A narrow canyon with towering, dark, vertical walls exited high above us, and a torrent of water poured through the narrow slot canyon exit and dropped 15m onto the river bed below. At the top of the waterfall we could see a concrete structure with old rusty reinforcing bar sticking out of it. We had found the dam and the end of Holts Creek canyon!
Little did we know that the next time we would see this dam would be from above, after 16 hours solid travel, in pitch blackness and the dead of night.
Mt Barron has a well-graded track, constructed almost to its summit. This track was constructed in connection with the tunnel works, for at the top there stands what is known to surveyors as a monument; a column of concrete on which is set a copper plate giving the exact centre line of the Otira tunnel, and from this point can be seen a similar monument at a distance of five miles. Much work was entailed in constructing this monument, as the cement and shingle had to be carried by men from the riverbed below and it involved several tons of material.
This recce confirmed there was no possibility of accessing the canyon from below. The only way in would be the long and steep climb up Mount Barron and a rugged descent into the headwaters of Holts Creek. It was not until March 2017 when the unstable westerly weather systems ceased and a window of opportunity opened. Otira has one of the highest rainfalls in New Zealand and the area had been hammered through the summer period. After the mandatory steak and cheese pie for breakfast at the Sheffield Pie Shop we headed over Arthurs Pass and parked next to the Rolleston River. With heavy packs we began the climb of Mount Barron grateful for the track as we ascended steeply through dense West Coast bush to the tussock tops.
After 3 hours enduring intense heat and a wasp attack we were standing high above the bushline in thick mist gazing down narrow gutted screes, occasionally glimpsing the creek head far below.
The wild narrow bush clad valley dropped steeply away below us and the first high horizon line was fast approaching.
Amphitheatres of rock with vertical sides surrounded us and successive multiple waterfalls exited into wide aqua blue pools. Huge jumps into these beautiful pools were imagined, but we had a big job to do and time was ticking by.
As we descended deeper towards the lower canyon a massive house-sized chockstone blocked our path, and the water siphoned away down a hole to our left. To our right was a narrow dark cave that lead around the side of the massive boulder.
We abseiled into this opening and found ourselves perched on a high horizon line looking out over the narrow lower canyon far below. We still had a long way to go!
This barrier presented us with the crux of the canyon. A traverse through the flow to river left was necessary, balancing on the edge of the 40m waterfall. Grant was like a rubber clad Spiderman, clinging to the super slippery surface whilst fixing anchors, as we held our breath in suspense.
The sky beyond was dimming and the late season sun was gone. After overcoming this obstacle we found ourselves swimming across yet another deep pool in fading light as the walls closed in around us. The next 20m waterfall dropped away into a deep inescapable slot canyon.
As the light finally vanished, a further waterfall channeled us down a constricted corridor and a long pool stretched out in front of us. Even in the near darkness we could tell that the water was a strikingly beautiful blue colour.
At the end of this pool the creek tumbled away into the darkness, veered right, and then out of sight over a large noisy waterfall far below. It was nearing 8.30pm and becoming pitch black.
Above us were dark, slick overhanging walls with no option of escape. There was no way we were standing here all night on this tiny inhospitable perch. We donned headlamps and got ourselves into night canyoning mode, determined to continue our descent.
A ledge presented itself on the true right allowing a dry but precarious high traverse to an access point, which offered a direct line down this next dark, unknown drop. The beam of our headlamps faintly made out a wide amphitheatre and the shallow tail of a large pool approximately 40m below.
A detailed discussion ensued and a plan of action and communication was made. Grant fully took one for the team, and descended away into the inky blackness; his headlamp illuminating the pour-over as he disappeared from view. We stood in the blackness, our eyes focussed and unblinking, waiting for him to reappear. In what seemed like no time a small light could be seen moving out of the pool. The flashing of headlamps confirmed the prearranged signals and the team was soon descending and assembled safely at the bottom marvelling at the beautiful pitch we had just negotiated by torchlight.
Once out of the pool we were relieved to now be safe on a wide, dry shingle shelf. We looked at each other and considered the possibility that this was where we were going to be spending Sunday night. Thoughts crossed our minds of puzzled colleagues on Monday morning wondering where we were at the start of a new week. Grant walked to the far edge of our shingle sanctuary and gazed down the next waterfall by headlamp. At the far end of a sheer sided pool he could just make out the remains of a concrete structure blocking the path. He beckoned Nola over and asked what she thought.
“I recognise that shape, we have made it!” was her reply. We could see the dam and the end of the canyon.
We were going home tonight!
Once again we descended down a dark unexplored waterfall, and suddenly found ourselves standing in a high pool next to the dam we had gazed up at on our original recce trip earlier in the summer. Water had broken through the dam over the last century but a surprising amount of the original structure remained.
Just as the ancient papers had described, to the left of the dam was a large smooth tunnel carved into solid rock heading towards Otira. It was very eerie and surreal to stand there 110 years later, in the dead of night, eating chocolate and marvelling at this incredible feat of human engineering hidden high within the slick, dark canyon walls.
A quick exploration down the tunnel lead us to a cliff opening and a sheer 30m drop into the creek where the wooden pipes would have collected the diverted torrent of water.
We retreated to the pool behind us. Anchoring a hand-line off the dam, we traversed to river right and descended the final pitch into the other branch of Holts Creek.
It was 11.00pm as we exited the canyon and completed the first descent. We were now on familiar ground.
One and a half hours away down this rugged West Coast creek was the car. There were no celebrations; just a quick refuelling and we began the walkout. Our spirits soared as the lights of the Otira tunnel finally came into view and we gained the access road down the Rolleston River. Never was there a more joyful feeling than reaching the car in those early hours of Monday morning. It was 1.40am when we finally removed our canyoning gear, packed the car, and began our journey East.
With tag team driving, it took all three of us to make it back to Sheffield where we had started our mission 21 hours earlier. A repeat was already being talked about and the possibility of big jumps into blue pools and exploring the beautiful and historic lower canyon and tunnel in daylight this time!
Fast forward one year to March 2018.
We once again met in the darkness at Sheffield pie shop HQ. The second descent was on a perfect blue sunny day.
It was a day of pure joy reminiscing and delighting in seeing the lower part of this magnificent canyon in sunlight rather than by torchlight.
We gleefully explored the tunnel and this time descended through its entrance, abseiling past an ancient wooden water pipe down to the creek bed below.
The car was reached at 8.30pm – just on dark. Arthurs Pass township was closed up for the night, so we drove on to the Bealey Pub for our traditional aprės canyon. And with a group of noisy locals in high spirits, and live music playing in the background, we finally celebrated, one year on, and raised our glasses to Holts Creek.
First descent team: Grant Prattley, James Abbott, Nola Collie
Second descent team: Grant Prattley, James Abbott, Nola Collie, Victor Mendes
You can take a look at the route guide and canyon diagram for Holts Creek on KiwiCanyons.org. Grant Prattley, James Abbott and Nola Collie spend a lot of time exploring and descending canyons in the Canterbury/Arthurs Pass region. They are all on the executive of the NZ Canyoning Association, which is affiliated to FMC.
Victor Mendes spent the Summer of 2018 in Christchurch and was a team member on a number of alpine canyon descents. Victor is also a member of the NZ Canyoning Association.