The old O-K Venturi Meter House was erected no later than 1926. Today it is concealed within the native bush of Wainuiomata Regional Park.
The Old O-K Venturi Meter House was likely constructed as part of the O-K pipeline and is one of several structures built as part of Wainuiomata’s water supply infrastructure over the years. This small concrete hut sits directly above both the cast iron pipeline and the earlier concrete water race, and probably dates to the early 1920s. Inside, the faint outline of the original flow-meter installation is still visible, once used to measure water passing through the pipe below. Water pressure readings were taken hourly, and a contemporary newspaper report notes that the Venturi meter itself was purchased on 13 June 1924.
Further, near the entrance and a window, is concrete sealing at each end of the hut marking what was once entry points to the water race. The race itself begins at Lower Dam and extends to Colemans Tunnel near Richard Prouse Park.
The concrete hut / house is of a rectangular design, measuring 3.365 meters along its longer side, corresponding to the track side or the south/north orientation. On the shorter side, measuring 2.455 meters, lies the east/west alignment. The height from the exterior to the arched concrete roof peaks at 2.5 meters. Positioned on the east side, the entrance features a window opposite on the west side, both fashioned from molded concrete.
Until the mid-1980s (perhaps later), the hut was visible from The Meadow which is known today as Hine Road Recreation Area. Over time, dense tree growth has obscured the structure from view. Its exact location is on an old track that ran parallel with Reservoir Road that use to accommodate four-wheel drive vehicles until about 2008. It was initially carved out for the Orongorongo Pipeline, since then, nature has almost completely reclaimed this stretch of the old track.
It is interesting that both the water race and the pipeline run underground. As a result, their maintenance tracks intersected at this point, though elsewhere along the hillside they followed different levels. It remains unclear whether the hut’s position directly above both was intentional or merely coincidental. If intentional, then the hut could date back earlier to the time of the water race.
At this stage of understanding, it is considered that the hut was constructed for the Orongorongo pipeline, but positioned above the water race. The measurements suggest that the hut replaced a section of the water race, rather than the race continuing directly beneath it.
