The lake, close to
Mount Cook National Park, is the second-largest of three roughly parallel alpine lakes running north-south along the northern edge of the
Mackenzie Basin. The other two lakes are
Lake Tekapo and
Lake Ohau; all three were created by receding glaciers which blocked their respective valleys with their final moraine that in turn acted like a ‘dam’ and therewith created the lakes. The glacial waters which feed the lake gives it the distinctive turquoise-icy colour. The lake is fed at its northern end - near the village of
Mount Cook - by the Tasman River, that has its source near
Mount Aoraki. The lake covers an area of 170 km2 and it forms part of the Waitaki Hydroelectricity system which results in water levels to rise and fall according to demand, snow melt and rainfall in the area.