Maraetotara Dam

Description

Mokopeka Dam at Maraetotara with man, possibly a Chambers, standing in middle

From ITravelNZ website –

Site of the historic Havelock North hydro-electric power station, opened May 17 1922 with a 180cm high dam on top of Maraetotara Falls to give a 21.3 metre head of water.

An 0.91m diameter concrete pipe was used as a penstock to carry the water 640 metres to the power house downstream to drive a 250 b.h.p. split wheel spiral case turbine turning a 750 r.p.m. generator.

The surge tower overhead takes care of destructive water hammer when the 430 tons of water in the pipeline, moving at 7km per hour, stopped in tree seconds.

At peak load a three – phase current was generated at 3300 volts and transmitted a distance of 9km over ten tons of cooper wire on ironbark poles through “The Gap” by Te Mata Peak to Havelock North before being stepped down to a standard 230 volts.

The total capacity of the scheme was about 30 000 units per month and designed to operate automatically with no resident attendant, just a service visit twice a week to lubricate machinery and clear intake screens.

The 1931 earthquake did little damage to the plant and in May 1937 the hydro-electric scheme was purchased by the Hawke’s Bay Electric Power Board who ran the plant until 1941 when a lightning surge damaged the generator.