A DOC and iwi initiative in Nelson Lakes National Park has helped protect an alpine lake from a new environmental challenge.
Walking in the footsteps of her ancestors and protecting a lake with the world’s clearest freshwater, made last summer rather special for Kylie Batt (Ngāti Apa ki te Rā Tō).
It certainly made up for leaving her job as a rafting and caving guide with Charleston’s Underwater Adventures, where she’d worked for 11 years before COVID knocked tourism for six.
Instead, Kylie spent the summer at Blue Lake Hut in the upper Sabine Valley, employed as the first-ever dual hut warden/iwi guardian for Rotomairewhenua (Blue Lake).
The hut and its adjacent clear blue lake have long been a popular side trip for trampers walking the Travers-Sabine Circuit. However, since becoming part of Te Araroa Trail the area has been overwhelmed.
People camping and cooking beside, and swimming and washing in, Rotomairewhenua had become particularly problematic from both a cultural and biodiversity perspective.
NIWA scientists have established that Rotomairewhenua contains the clearest natural fresh water in the world.
The lake is spring-fed from Rotopōhueroa / Lake Constance, its water passing through landslide debris that filters out particles and gives Rotomairewhenua its clarity and intense blue-violet colour.
Now there’s a new threat to it staying that way; a microscopic organism known as lake snow, which can pollute lakes with slimy, sludgy brown algae. Lake snow has been detected in lakes Rotoiti and Rotoroa and no one knows how to get rid of it. Fears are that it will spread to Rotomairewhenua and Rotopōhueroa.
Local iwi, Ngāti Apa ki te Rā Tō, used Rotomairewhenua for traditional cleansing ceremonies, to release the spirits of deceased men. Rotopōhueroa was used for ceremonies involving deceased women. Both lakes are regarded as tapu.
The decision to employ a hut warden for Blue Lake Hut revolved around addressing both the biodiversity threat and cultural dimension, says John Wotherspoon, DOC Nelson Lakes operations manager.

