Blue Lake Nelson – the cleanest in the world

Blue Lake (Rotomairewhenua in the Maori language) is a small freshwater lake located in the Nelson Lakes National Park, in the Southern Alps of New Zealand. Scientific research conducted in 2011 by the National Institute of Water and Atmospheric Research of New Zealand (NIVA) showed that the Blue Lake is the most transparent and bright natural body of fresh water known to man. 

According to the results of NIVA's research, the visibility in the lake is 80 meters — this means that the water as "optically transparent" is equal to distilled water.

The Blue Lake became known from the local tribe after the opening of the park in 1956. The indigenous people of the tribe consider the lake sacred and carefully ensure that no one enters its waters. The only exception was the Danish ecologist and photojournalist Klaus Timann, who was granted an exclusive permit to shoot and study the lake.

The lake is fed by a source from the nearby glacial Lake Constance, but the water passes through landslide layers that form a dam between these two lakes. A natural dam filters out the water, giving the lake the most intense natural purple-blue color.

Nelson National Park in the northern part of the South Island has become a popular place for fishing and recreation. The route along the lake is a two-day hike from the border of the park. There are also observation decks and, if desired, you can book helicopter flights to admire the natural beauty from a bird's-eye view.

The height of the lake above sea level is 1200 m. The water of the Blue Lake is always cold, within 5-8 ° C.