Aratiatia is the first hydro station and smallest hydro reservoir on the Waikato River. About 13 km downstream from Taupo, Aratiatia is largely a ‚run of river‘ station passing water released from the Taupo Gates down to Lake Ohakuri.
The Aratiatia rapids are one of the river’s outstanding scenic features. Mighty River Power releases water down the rapids several times each day, attracting more than 60,000 visitors annually. A road bridge across the top of the rapids, tracks and viewing platforms, provide excellent vantage points from which to see the rapids.
The potential of the Aratiatia Rapids for electricity generation was first recognised a century ago. However, because of their scenic qualities and the discovery of geothermal activity at Wairakei, development did not proceed at this time. It wasn’t until 1954 that the government began investigating ways to use the area’s potential to generate electricity, while protecting the distinctive natural features. This meant that Aratiatia was the eighth and second-to-last of the Waikato River power projects to be completed.
Work began on the site in September 1959, and the lake was filled in March 1964 in time to forestall an expected electricity shortage.
For the power station to be constructed, the original channel at the top of the rapids was plugged with earth and the water diverted into an open cut on the riverbank where the spillway now sits. Unlike other power stations on the river, there is no dam other than the earth plug and spellweir. This is because the Waikato River falls sufficiently at this point to provide a natural ‚head‘.
Nearly 750,000 cubic metres of material was excavated to provide sites for the surge tank and powerhouse. The penstocks are buried in the area between the surge tank and the powerhouse. A road now passes over these to the powerhouse tailrace. Extensive landscaping and tree planting after construction provides a very attractive setting today.
How Aratiatia got it’s Name
Aratiatia literally means a series of pegs stuck into a steep ascent in a zig-zag pattern to make climbing easier. It may also refer to the travels of the ancestral explorer Tia of the Arawa canoe who made his way to these rapids while exploring the Waikato River
Source: Mighty River Power