By Kerry Magnuson

Trip: West Mathias River (Grade IV-V, Length 4km, 2km @ 60m/km + 2km @ 30m/km)

Paddlers: Ben Longworth, Matt Hansen, Kerry Magnuson, Paul Mason

Date: First descent on December 10th, 2021

Duration: 5-6 hours

The West Mathias is the middle branch tributary to the Rakaia river, adjacent to the Wilberforce. It stretches deep into the Southern Alps. Being a remote region, it is prone to weather extremes and only frequented by hunters or hikers. This story is of its first descent by kayak, exploring the white water potential.

A small team of hardy paddlers ventured into the Mathias valley with whitewater kayaks, shouldering them to the top of the rapids. On the way in, Kerry tripped and broke his thumb. However, that did not deter from the excitement of doing a first descent – the pinnacle of white water kayaking.

Paul Mason and Matt Hansen scout a long technical rapid (this all got paddled)

The section above the West Mathias bivouac is steep! It is a short two kilometres, but falls at 60m/km in a series of tight rapids with fast lines and micro eddies. The water is a typical clear blue, reflecting its origins from glaciers off Mt Warner and the Agassiz range, and the mountain tops rise so high they rest among the clouds. It is breathtaking scenery.


Paul Mason starts at the headwaters

The rapids reflect West Coast boating; tight technical moves among steep rocky rapids with little let-up between. The team cautiously took their time descending the top two kilometres, eddying out where possible to scout the next drop.


Ben Longworth powers across a steep section

Three rapids of note reached grade V and most rapids were grade III+ to IV+, with one double drop being a hoot!


Paul Mason exits the cool double drop

Approximately 90% of the run was paddled and we had the good fortune of not experiencing any incidents, while the top two kilometres took five and a half hours back to the bivvy and another hour or so to the North Mathias confluence. There were still a few rapids below the bivvy.


Paul Mason comes out of a tricky section

Scouting the Mathias during a storm had proven difficult; however, tackling it in optimum conditions had produced an absolute pearler. When the Rakaia was 200 cumecs, a storm spilt over the Alps into the Mathias and made that too high to paddle. Yet when the Rakaia was 400 cumecs, most of that was dropping into the Rakaia headwaters and the Mathias was a perfect flow.


Photo 1:  Ben Longworth on a clean boof; Photo 2:  Paul Mason drops into a drop-to-shoot rapid

It is always going to be a guessing game to get the optimum flow to paddle the West Mathias again and due to the steepness of the run, you would not want high water up there. Another factor to consider is the high wind in this area, which whips up wind funnels and stinging sands. But aside from the challenges to get to the river, this one is worth the effort!


Kerry Magnuson giving chase

We launched our Outdoor Community campaign in 2015 to showcase the diverse range of recreational pursuits that our member clubs and individuals are passionate about.

Our celebrated activity for 2022/23 is Whitewater Kayaking. Kayaking is a chance to explore the backcountry in a different way from tramping on land, and instead of being an obstacle to get past, paddlers can use rivers as a method of travel and source of adventure.

So, keep an eye out in places like Backcountry magazine and our blog for stories, articles and resources on water kayaking. As always, if you or your club has ideas or stories to share, please get in touch. We would love to hear from you.