Showing posts with label River Reconnaissance. Show all posts
Showing posts with label River Reconnaissance. Show all posts

Sunday, 31 January 2016

Otira River Crossing Reconnaisance: 30th January

A look at the ford over the Otira River.... 

My six day trip over Harper's Pass is coming up in two weeks time , so I went to the West Coast over the weekend to scout the crossing points on the Otira River.

(NB: It didn't happen due to a massive sodding rain event...)

The Otira River at Aickens Corner, Arthurs Pass National Park

Travel up the Taramakau means river crossings....

To get over Harper's Pass you must be able to cross the Otira, Otehake and Taramakau Rivers on the first and second days of the tramp. There are no bridges crossing any of these rivers, so you need to utilise those river crossing skills to get through. The Otira is generally the worst of the three, if you can cross this river at Aickens Corner you should be able to cross the other two as well. 

Otira Ford point at Aickens Corner

For more information on river crossing technique you should read the relevant sections of the MSC books:  Bushcraft : outdoor skills for the New Zealand bush and River Safety: Be river safe.

Every serious tramper should have a copy of both of these books at home.

The Bushcraft bible: Bushcraft in New Zealand

MSC River Safety Manual: must know river crossing techniques

The Otira, Otehake and Taramakau Rivers are all killers: numerous people have been swept away trying to cross them in unfavourable conditions. They are always cold and can be deep and swift with even a hint of rain in the surrounding mountains.

This is the West Coast remember: it is always raining in the surrounding mountains.

Track to the Taramakau Valley from near the Aickens car-park

The photo below is of the Otira directly opposite the track from Aickens. The water looks deep but I watched a party of three trampers cross here, the water only reached their knees so this is the first of three potential crossing points.

It is about 20-30 meters wide so it is a long way to back-track if things started to look dicey during your crossing. I would still think about fording here but I would think long and hard before wading in. 

Otira River: First possible ford near Aickens Corner
About 100 meters up the river it is a different story: it looked sphincter puckering! Deep and fast flowing as the river is confined to one very narrow channel. You can see an obvious pressure wave in the river which is a classic danger sign.


Otira river view towards the flood track near Aickens Corner
I headed up the river about 400 meters and found a good crossing point where the river breaks into three braids. You can just see the potential crossing point about 50 meters upstream of this spot, the river crosses a shingle fan and becomes shallow.

View upstream: Otira River ford near Aickens Corner
 I walked over the first two braids and it was halfway between ankle and knee depth. Provided it doesn't rain too much I should be able to get over the river easily enough here. 

The multi braided section of Otira River near Aickens I walked across
Multi braided section of Otira River, Aickens Corner
You would basically cross from channel to channel via the intersecting island's.  Also, there is good run out into relatively shallow water if something goes wrong. Run out is what happens with the water downstream of your crossing. You want it to be clear, preferably shallow with no boulders, snags or rapids..if you go for a swim you don't wont to be colliding with anything.

Piece of piss then: No... not really but at least you would be safer crossing here.You are never 100% safe crossing any river in New Zealand, you need to respect them.

Multi braided section of Otira River looking towards the Taramakau

Just a note, there used to be a small shelter on the tongue of land between the Otira and Taramakau. It was about 300 metres from the river got carried off in a flood in 2014!

 Something to think about....

Multi braided section of Otira River at Aickens,  looking downstream...

There was also a potential crossing point about 50 meters downstream of the straight through route, again the river breaks into two wide channels slowing the speed and force of the water. It is a possibility but I wasn't as fond of the run-out, it looked deep just downstream of the crossing point, if you went swimming you might find it hard to get out again. This would be my least favoured option.

Different day...the Otira River after 1-2 hours light rain in the headwaters...
Please note: If you are unable to cross the Otira River at the ford then you will not be able to cross the Taramakau or Otehake Rivers.
Anyway that's what this beast looks like, whether it is the same in two weeks remains to be seen. 

P.S: I gave a couple of TA walkers a ride from Arthur's Pass to Lagoon Saddle Track. One of them got swept away by the Otehake a couple of days earlier but managed to make it to shore. He freely admitted he just waded into the river and didn't take the time to study it well. Always study a river before entering.

Crossing the Morrison Footbridge just west of Otira

Access: Aickens Corner is approximately 5 km's west of Otira township, there is a parking area on the right hand side of the road.
Track Times: The ford over the Otira River is located 10 minutes along the track to the Taramakau Valley, please follow the marked track as it crosses farmland.
Miscellaneous:The Otira can also be crossed via the Morrison Bridge, this is approximately 1 km west of Otira. Then use the Otira Flood Track to access the Taramakau- note that the flood track is overgrown and in poor condition, it takes 1.5-2 hours.