A study discovered that Nelsons Blue Lake (Rotomairewhenua), at the top of New Zealand’s South Island, has some of the clearest water in the world. The water is thought to be near as “optically clear” as distilled water. The fact that the lake’s clarity was close to pure water, according to Niwa aquatic optics specialist Rob Davies-Colley, was extremely significant.
Blue Lake In NZ Has Been The Clearest Lake In The World For Many Years Until Today
Blue Lake (Rotomairewhenua in Mori) is a sacred lake in Nelson Lakes National Park, in the northern reaches of New Zealand’s Southern Alps. It is now thought to have the clearest natural fresh water in the world. According to the National Institute of Water and Atmospheric Research, visibility in Blue Lake can reach up to 80 meters (262 feet). The water is thought to be near as “optically clear” as distilled water. It outperforms the nearby Te Waikoropupu, or Pupu, Springs in Golden Bay, where visibility of up to 63m (206 ft) has been reported (Image at the bottom). Water visibility was considered exceptional when it exceeded 40m (131 ft), according to Niwa.
“Nelsons Blue Lake is distinguished by blue-violet hues seen only in the clearest natural waters, and it is unique in its geological and hydrological setting, being spring-fed from nearby glacial Lake Constance. Almost all suspended particles appear to be filtered from the water as it flows through landslide debris that forms a dam between the two lakes, which accounts for the water’s extreme clarity.” According to Niwa scientist Mark Gall.
Researchers suspended a meter-wide black disc under a buoy and then paddled away in a boat while looking at the disc; visibility was measured when the disc vanished. The fact that the lake’s clarity was close to pure water, according to Niwa aquatic optics specialist Rob Davies-Colley, was extremely significant.
Why Is Blue Lake In New Zealand So Clear?
The lake’s clarity is attributed to its underground passage from Lake Constance, which filters out nearly all of the particles suspended in the water. Its clarity reveals the natural blue-violet color of the water.
The Best Time To Visit And Get There
Blue Lake is a multi-day hike that can be accessed from the alpine village of St Arnaud, depending on the direction you want to travel and the amount of time you want to spend. Take the water taxi from the Lake Rotoroa Jetty for a short weekend trip. Longer trips can start from Lake Rotoiti and follow the Travers-Sabine circuit.
The best times to see this natural wonder are late spring, summer, and autumn. Winter and early spring should be avoided because there may be icy rind stretching across the lake.