Power Stations

Construction of the powerhouse and penstocks. Karapiro was completed in 1947.

The large concrete deflectors shown in the photo above are normally underwater in the canal that provides water to the maraetai 2 power station. The defectors are designed to smoothly direct the flow toward the turbine intakes without whirlpools and eddies that would otherwise dissipate some of the energy.

Left abutment stability enhancement.

Left abutment stability enhancement 1999.

Waka are a rare sight on the hydro lakes, but are often used at major events to pay respect to and symbolise the special significance of the river to Maori.

Waipapa power station is sited in picturesque surroundings near the junction of the Waikato and Waipapa Rivers. As the smallest power station on the Waikato River, the role of Waipapa is to supplement other stations during periods of heavy demand.

The Whakamaru power station plays a pivotal part in the Waikato River hydro system. As well as being a significant contributor of electricity to the national grid, the main switching station receives the power generated from all the upper Waikato stations, and supplies the transmission system that leads north to Otahuhu and South to Bunnythorpe and Haywards.

The two Maraetai stations have a combined capacity of 360MW - the largest output from any lake on the Waikato River. Pictured Maraetai II.

At times and for various reasons such as floods or machine outages not all water stored in a reservoir can be channelled through a power station and so must be released through a spillway.

Karapiro is the ninth and last hydro power station on the Waikato River and is 188km downstream of Lake Taupo. The lake is probably best known as a world-class rowing venue and the location for many other water sports events including yachting, powerboating and water-skiing.

Lake Ohakuri is the largest lake on the Waikato River and plays an important role in the management of daily water flows in the Waikato hydro system.

The Arapuni power station has eight generating units, giving it the largest capacity of any single station in the Waikato hydro system. The station's close proximity to Waikato's large urban and industrial area means the station is available to provide voltage support and frequency keeping in the area.

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.

Atiamuri power station is 8 km downstream of Ohakuri and takes water directly from the larger upstream station. The relatively small storage of lake Atiamuri means the timing of its generation production is critical, particularly if Ohakuri is generating at full capacity.

The Maraetai dam site lies in a narrow gorge where the Waikato River cuts through ignimbritic sands and gravels. On completion of the dam, the gorge was filled to create Lake Maraetai.

The site has been de-watered with the drilling of a diversion tunnel (521m long and 7.6m diameter) and building of coffer dams. In the foreground, the foundations for the base of the dam (width 15.2m) are being excavated. In the centre of the photo, the power station is taking shape.

By April 1951, construction on the power station (centre right) and dam (centre) is well-advanced. Clearly visible is the upstream coffer dam diverting water through the diversion tunnel. A cableway, with gantries mounted on both sides of the gorge, moved heavy materials around the site.

The spillway, seen here under construction, was used to form part of the diversion tunnel and is sited on the left abutment of the dam.

The two Maraetai stations have a combined capacity of 360MW - the largest output from any lake on the Waikato River. Pictured Maraetai II.