Trip Overview
Access 13, or the Pillars of Hercules Run, is a very scenic run that can be scratched through at residual flows but is best done on one of the scheduled release days. The tracks in and out are tricky. Above this run is the deadly Tree Trunk Gorge and below it another deadly stretch above Waikato Falls. You must know the take-out as the bottom gorge can not be run (a kayaker died here in late 2019).
Shuttle
If you base yourself at Urchin or Kaimanawa camp sites off Kaimanawa road you can walk to the put in. A car shuttle is easy. Drive back south on SH1 to Tree Trunk Gorge Road and drive until you cross the bridge. Check out the spectacular view of the Tree Trunk Gorge beneath the bridge. Leave a car at the Bridge on Kaimanawa Road. If hitching convince your ride they must see the Tree Trunk Gorge view from the bridge (or walk 4 km).
On Foot
From the Bridge above Waikato Falls walk up the gravel road past the Urchin campsite turn-off until you reach the Kaimanawa campsite (half an hour). Then follow the well-graded tramping/mountain bike track to Tree Trunk Gorge Road (one hour max). Immediately after the last sidestream before the road, there is a signposted access to the river. Use this if you don’t mind missing the spectacular paddle upstream into the bottom of Tree Trunk Gorge (don’t miss it). Carry on up the track until it approaches the cliff-edge. There may be a spike in the ground used for lowering gear (present in Feb 2020). Work your way carefully down to the river. If it’s wet and slippery rig a safety line with your throw bag.
Another access used by kayakers is on river left at the bridge. An obscure entry leads to a well defined track to a cliff edge where boats are lowered. An obscure track (we missed it) winds around to the left and then down to the river. Apparently there are some ropes to assist.

On the River
Paddle upstream a few hundred metres on flat water through an overhanging gorge to the base of the last drop on Tree Trunk Gorge. This upstream gorge has claimed the lives of a number of paddlers including some who were unaware of its existence. Don’t get too close to the base of the waterfall, view it from a safe distance.

From the gorge down it’s pretty straight forward Class II or II+ at low flow. In places the channel splits and it’s a guessing game. Most rapids are boulder banks. At higher flows of say 10m3 after rain it can be Class III or during a release Class III +.

After an hour the river meets a huge cliff, the Pillars of Hercules, with a narrow flat-water gorge cut through it. You can get out before the Pillars gorge on river left where a walking track leads you back to the road between Urchin and Kaimanawa Campsites, but there’s some nice river below so paddle on. After some more Class II/III below the Pillars watch out for overhead transmission lines. There is one rapid after these and then a stretch of flat water to the take-out. Below the take-out is a section that can not and must not be paddled. As recently as 2019 the unpassable gorge took the life of a kayaker.
Do not go past the sign that says “do not pass this point”. The bits that kill can not be seen from the road.

From the sign head perpendicular to the river until you cross a small stream or wet gut. From this point a rather precarious track leads up the cliff angling to the north. Halfway up you may see ropes that are used to pull kayaks up. The difficulty of this portage means it is run a lot less than it might be. But for Packrafters it’s an easy 15 minute walk to the bridge where you can look at the nasty gorge or carry on 5 minutes to the access 10 put in.
Some parties abseil into the pool immediately above Waikato Falls to take the drop. Do some research before even contemplating this.
Gauge
The nature of the river that is visible from the road is quite different to the wide river bed between the gorges so it needs more water than you would think. We ran it at a couple of cumec in February so it should be do-able for much of the year. Release days are scheduled and the river is a mighty Class III+ on those days. I have not been able to determine which gauge is best. This is because the river is part of a hydro scheme which takes much of the water through tunnels around this section and then dumps it back in the river below Waikato Falls. Water is then removed again at the Poutu Canal intake. Have a look at how much water is flowing through Tree Trunk Gorge and then decide.
When we paddled it it may have been only 2m3. This meant we slid down wet boulders in some places and walked in others but it was still a nice trip. Apparently the gauge should be above 10m3 for this trip to shine.