Lake Waikaremoana lies 610m above sea level and the fall of the Waikaretaheke River is 448m within 8km. The hydroelectric generation potential of the area was noted towards the end of the First World War when extensive surveys were carried out. An initial local scheme to supply power to Wairoa was completed in 1923. This was necessary because river bar conditions at Wairoa often stopped the supply of coal to the town and freezing works.
Until hydro-electric developments, the lake’s normal outflow was by leakage through underground channels near the outlet into the Waikaretaheke River. Before Kaitawa was built only in very wet seasons did the lake overflow at the outlet. When construction started, leakage had to be sealed off so that the lake’s flow could be controlled. Divers pinpointed the underground leakage channels and barges dropped rock-fill to seal them.
The Tuai Power Station, designed to accommodate three generators, was officially opened in 1929 with only two units in place , the third generator being added in 1939. Work on the Kaitawa Power Station began in the early 1930s. Some delays were experienced and the two generators did not begin delivering electricity until 1948. Construction of Piripaua began in 1939 and the two generators began producing in 1943, becoming fully operational a year later.
Today the scheme makes use of Waikaremoana’s water by carrying it to Kaitawa Power Station and then, via Tuai Station into Lake Whakamarino. The water then passes on to Piripaua Station before being finally discharged into the Waikaretaheke River.
Maori Legend
Having created Lake Waikaremoana during her wild frenzy, the taniwha Haumapuhia heard the roar of the great ocean of Kiwa far to the east and decided to try and reach the ocean before daylight broke. She thrashed her way through a cleft in the mountain range at Te Whangaromanga near Onepoto but suddenly daylight, which is fatal to taniwha, came upon her. Haumapuhia was turned to stone and lay in the river bed with her head facing the ocean and her legs towards Waikaremoana. The water filled the gouges she had left, so forming Lake Waikaremoana. Maahu, her father was so overcome with remorse at having drowned his daughter that he went to the ocean of Kiwa and brought the river up to her with fishes and food for her sustenance. In so doing he earned her forgiveness. Haumapuhia lay undisturbed in the river bed for many many years until the waters of the Waikaretaheke River were diverted for the hydro-electricity scheme. It was then, just before the completion, that a landslide completely covered her and she can be seen no more.