Some hiking routes fall into the adventure category. By rights, the route should not exist and over time may not be viable. For now, the Kaapoko Trail was unknown even to island residents until an adventure writer found enough information to describe the route in the best-selling The Ultimate Kauai Guidebook. With each revision, more information was added and each year adventurers attempt the route. In time, it may a real trail (if the tunnels remain passable).
The tunnels were built to divert water from the north-facing slopes of Mount Waialeale, near the source of the Hanalei River, to the east side sugar cane fields. A dam was built in the high valley in the 1920’s and 23 million gallons of water each day was diverted into gullies and ditches for the cane fields of the east shore hills. When sugar production dwindled on the Hawaian Islands, the dam, diversion ditches, and tunnels fell into disuse and disrepair. Right below the wettest spot on the planet, the rains and torrents eroded away many of the man-made structures and the jungle began to take over. But the tunnels were cut through solid rock and even after almost 100 years, they are still mostly clear, but they are deep below the mountain, dark, wet, and a little creepy.
The route from the trailhead to the tunnels and through to the Hanalei River and back is about 8 miles. It takes most groups about 8 hours to complete. This is slow progress, but this no ordinary route. The back road to the trailhead is rough, with rocky sections, potholes, and stream crossings. 4WD. The trailhead (at N22 04.850 W159 27.688) is unmarked, a mud path into the jungle.
From the first step to the last, the hiker will be in the mud. Even in drier periods, some sections will leave you covered in mud up to mid calf. The whole route is slippery, overgrown, and difficult. Route-finding is an issue. A few prices of flagging tape helped and I used a whole roll myself to help mark the route. Climbing over logs, stumps, and rocks, crossing streams on slippery rocks, scrambling up banks, pushing away the vines and clinging branches, and traversing mud holes is just the reality of the route. You will get wet, muddy, scratched, and battered. You will slip and fall. And this is just the first 2.5 miles.
If you can stay on the trail, you will arrive at the entrance to the first tunnel.
This section is one mile long and straight. A distant point of light can be seen. The tunnel is about 6 feet high in the middle (it is lower at the sides) but there are places I needed to duck. The floor is rocky and ankle to calf-deep water is in the whole tunnel. The tunnel becomes very dark quickly and a headlamp or flashlight is needed to avoid tripping over rocks or bashing your head. At about 2/3 of the way through, light gauge rail lines can be seen on the floor of the tunnel, left from the excavation process.
After a lot of sloshing, an exit is reached, although it is not the route to the river. Out from this exit is a stream gorge, waterfall, and exotic tropical growth.
With a little bit of exploration, I found wild orchids and flowering impatiens. The route to the Hanalei River is not out this exit. It is down a dark side tunnel. This second tunnel was utterly black. It had support beams that require some scrambling through. The tunnels make several turns and the water was deeper, colder, and muddier. It was at this point that my hat and headlamp were torn off and fell in the muddy water. I rescued the headlamp first. Going back through these tunnels alone without a light didn’t seem possible. The light survived its swim, but the hat was forever stained and grimed by the mud. Eventually I found the exit, came out in the sunshine, but lost the path. I found myself in another tunnel crawling on hands and knees, and emerged at a waterfall below the old dam. A beautiful spot, but the wrong one. Back through the low tunnel, I found a side trail over a ridge, then down to the Hanalei River. Already a big river with clear water, I picked a spot for lunch and a rest before heading back.
Even though I knew what to expect on the way back, I found the second tunnel very creepy, with echoes from my sloshing feet and old items on the floor of the tunnel making dark shapes under the water.
After about an hour and half underground, I was happy to be out in the afternoon sun and on a muddy slog back to the jeep.
The route took me 6 and a half hours. I made several wrong turns and took many pictures so I was happy with my overall speed. But, I was muddy everywhere. Scratches on my legs are still healing. Some of my gear is permanently stained.
It was a challenging day, but a memorable one. Next time, I won’t go alone. The challenge will be to find someone who won’t resent it afterwards!
On the way back out, I met a young man who was busy with a machete, cutting back shrubs growing over the trail. He and his friends were going to backpack the trail and camp on the Hanalei River. This variation is now on my list too.
