Kourarau Power Stations
Engineering Work (eg road, bridge, sawmill, dam)
The Wairarapa Hydro-Electric Investigations Committee of 1916 investigated five rivers in the Wairarapa region before deciding on the development of the 219 metres (m) of fall available on the Kourarau Stream in the area known generally as Tupurupuru east of Gladstone.
The first of two stations which utilises 131 metres of the total fall was built in 1923. Generally known as the Lower or A station the installation comprises a diversion dam on the stream at a point between 4 and 5 kilometres east of Gladstone on the Gladstone-Te Wharau Road, and a 0.78 m diameter concrete pipeline which runs west for 1182 m before dividing into two steel pipelines of 0.53 m diameter. These pipelines supply a Boving twin disc Pelton wheel turbine driving a General Electric 700 kilowatt (kW) generator. A surge tower (described as Number 1) is located near the head of these pipelines. The powerhouse discharges into the lower reach of the Kourarau Stream just before it merges with the Waingongoro Stream, a tributary of the Ruamahanga River.
A year after the A station was commissioned a flash flood breached the diversion dam and damaged the powerhouse. The station was back on line in a month. Later some modifications were made to reduce its vulnerability to floods.
A further 88 m fall was developed by the construction in 1925 of the Upper or B station which includes a dam on the upper level of a bend in the stream (where it turns towards the southeast) a tunnel through the ridge towards the lake behind the 1923 diversion dam, and a surge tower (number 2) and a steel pipeline of 0.61 m diameter passing below the Gladstone-Te Wharau road to a powerhouse at the diversion lake. Here a Boving single disc Pelton wheel turbine drives an ASEA 250 kW generator.
An interesting feature of the schemes operation has been the need to clean a lime deposit off the pipe walls from time to time in order to maintain the power output. This cleaning has been achieved by the use of a device known as the 'hedgehog'. It has been described as “a leather bag resembling an open-ended rugby football. An external frame carries a series of steel wire brushes under tension against the pipe interior applied by a steel spring ring.”
The Kourarau stations were pivotal in initiating the reticulation of electricity in the Wairarapa eighteen months before the arrival of power from Mangahao in 1925 and 5 years before power from Waikaremoana in 1929. With power available from the developing national grid the Kourarau stations took on the role of reducing the Wairarapa Power Board’s peak demand on the State system until in 1930 agreement was reached to feed power from Kourarau into the national grid.
Related IPENZ records:
Mangahao Power Station
New Zealand's electricity system
Waikaremoana Power Stations
The conception, design and construction supervision of the two Kourarau stations was carried out by the engineer Harry Richard Climie who was also responsible for the design of six other hydro-electric schemes for other local bodies between 1913 and 1930. The stations today are operated by Powerco on behalf of Genesis.
Visitors to the area who pass through the Tupurupuru locality from Gladstone on the Gladstone-Te Wharau road will see evidence of the scheme in the two surge towers, the pipeline from the upper dam, and (if a deviation is made on the Kourarau valley road) the upper dam and lake. The latter is well regarded for a trout fishing.
This place has been recognised by Heritage New Zealand as a Category 2 historic place (List no.7814):
Kourarau Hydroelectric Power Scheme: New Zealand Heritage List/Rarangi Korero information (www.heritage.org.nz)
This description of the Kourarau stations has been compiled from Neil Rennie’s book Power to the People and the resources of the Wairarapa Archive of the Masterton District Council courtesy of Gareth Winter (Archivist).
Eastern end Te Wharau-Gladstone Road
Take Gladstone road from Carterton
Nature of Engineering
Electrical Power Generation and Distribution
Lat: -41.092584 Long: 175.702225