concrete reinforced forebay has a gravel trap and a sluice gate which allows it to be cleared without having to drain the canal. Provision was made in the structure for a second pipeline but it has never been built. From the forebay a long diameter steel pipeline (raised above ground level on concrete cradles) leads to a surge tank. The base of the diameter surge tank is constructed of reinforced concrete rising above ground before continuing in steel to a height of . Three penstocks long take the water from the surge chamber down a one in 10 gradient to directly connect to Francis turbines coupled to synchronous generators in the powerhouse, which is located on the west bank of the Waiau River. The 6.6 kV output from the generator connect via switchgear to two transformers, which transform it to 66 kV for transmission. The outside of the powerhouse foundation raises above the generator floor to form a tank so that the Waiau River into which the station discharges can rise above the floor level before generation has to stop. Operation The power station is subject to 18 resource consents which cover its ongoing operation and maintenance. They control the take, use and discharge of water for power generation, while maintaining minimum flows in all of the existing waterways. The resource consents are valid for 30 more years of operation.. See also List of power stations in New Zealand Notes References Further reading External links Pioneer Energy website Department of Conservation - Lake Monowai/Borland Road information page Energy infrastructure completed in 1926 Hydroelectric power stations in New Zealand Buildings and structures in Southland, New Zealand