After our Christmas tramping trip was shortened by bad weather we made some tentative plans to return to the area over the holiday weekend in early February with the hopes of finally making it to see Blue Lake in Nelson Lakes National Park.
After spending the days leading up to the trip studying the weather forecast, we eventually decided to trust what they were saying and head to the mountains. As we drove over Lewis Pass and the thermometer in the car read 5 degrees Celsius, and the rain pelted on the roof so hard it was difficult to chat, we started to second guess our decision. However, by the time we arrived at the head of the lake ready to meet our water taxi, the clouds were starting to clear as promised.
After a chilly night, the next morning was ideal for hiking up the Sabine Valley. Although the track climbs steadily through the forest for most of the way, we occasionally had glimpses of the surrounding mountains, each with their fresh dusting of snow! We knew it had been chilly overnight, but we were still quite surprised to see just how much snow there was considering it was high summer.
Although we had only recently walked this track, with the sun out, it felt quite different. The dappled light coming through the forest seemed to highlight all the different shades of green in the forest. In places even the rocks and tree trucks were covered in various plants, mosses and lichens.
The next day we planned to do a day walk up to Blue Lake and were pleasantly surprised when the weather forecast was correct and we were greeted with perfectly clear blue skies. After walking up the valley for a while, we crossed the first of a couple of large, historic avalanche paths which gave us great views up towards the head of the valley. The scenery was different to a lot of the other valleys we had hiked in New Zealand and reminded me a little of parts of the European Alps.
After another couple of steep sections of track we got our first glimpse of Blue Lake. With the angle of the sun, the lake itself actually appeared to be quite an unnatural shade of green, which was quite surprising. However, as our eyes adjusted, we started to see just how clear the water was, and how much of the lakebed we could see.
Tests conducted during 2010 and 2011 found that the water in Blue Lake was some of the clearest in the world. During tests, the visibility in Blue Lake was found to be typically around 75 metres to 80 metres, which is very close to the calculated value for distilled water (83 metres).
The lake is fed by a spring, with the water likely coming from Lake Constance further up the valley. As the water passes though a landslide dam between the two lakes, it is naturally filtered by the rocks removing the impurities. In addition to the naturally filtered spring, the lake sits at an altitude of around 1200 metres above sea level, which keeps the water temperature low, reducing the chance of organic matter clouding the water.
We found a sunny spot with views over the lake for our picnic lunch, and as we ate, we were lucky enough to see a Whio (Blue Duck)paddling around. Blue Ducks are only found in New Zealand and there are thought to be less than 3,000 of them left so we were incredibly lucky to see one. After lunch we made the 140 metre climb up to Lake Constance.
If the scenery on the hike up reminded me of the Alps, Lake Constance felt a lot like some of the high altitude lakes in Colorado. Both Blue Lake and Lake Constance are sacred to the local iwi, with the pure water in both lakes being seen as a taonga (treasure) that helps link past, present and future generations, so you aren’t able to touch the water.
After enjoying the views and the beautiful afternoon by Lake Constance, we started to retrace our steps back towards the hut. The views coming down the old landslide between the two lakes were amazing and the added height above Blue Lake allowed us to really appreciate how clear the water was.
After a relaxing night at the hut, we set off early the next morning to retrace our steps back to the jetty to meet the water taxi. We were lucky and had almost ideal conditions for our trip across the lake, especially as we could already see the high cloud building again over the upper valley.