Cave Stream is one of the more unique adventures in the area around Christchurch. As the name suggests, it is a stream that runs through one of the limestone caves up in the mountains. However, this doesn’t begin to describe the experience of walking through a stream underground for over an hour with no light and just the sound of the running water.
The adventure starts in a small car park just off one of the main trans-alpine highways, there are a number of trails, but one zig-zags down the hillside to the banks of the river. After a short walk along the river you come to the mouth of the cave. The wide open mouth is by far the largest section of the cave and the water in this section is also the deepest, making it the gauge for the rest of the trek.
Quite quickly the cave makes a turn and you loose all daylight. The steep sides close in quickly creating a underground canyon. The river varies in depth through the cave, at times flowing quite quickly through steeper sections.
Even with powerful headlamps, the scale of the cave makes it hard to see more than a short distance in front of you. Occasionally you get glimpses of waterfalls off to the side or carved rocks high up on the cave walls. Despite the cave system being just off the highway and open to anyone who wants to explore, once you start heading into the cave you rarely see other people.
You become accustomed to just seeing the clear water below you and a small area of the cave walls on either side. The rocks amplify the sound of the water in the river, which combined with the darkness makes you loose all sense of time.
Further into the cave, the canyon narrows further and twists and turns more sharply, creating what feels like the slot canyons we used to explore in Utah. The deep pools that form around the sharp bends can be quite a cold shock and you have to tread carefully through the fast flowing water.
The canyon ends abruptly and a series of metal rungs appear in the cave wall just in front of a large waterfall. Climbing up the ladder you are hit with the warm air coming in from the exit of the cave.
The final adventure involves crawling along the narrow ledge to reach the main level of the river. You can just about make out the metal steps and chain that help guide you along this section in the picture above. From here it is just a few minutes walk back to the car park. Despite having been underground for more than an hour and covering almost 600 metres (over a third of a mile), when not following the meandering course of the river there is very little distance between the mouth and the exit of the cave.