In 1876 a report was written for the Dunedin City Council outlining the various options available for the supply of water to the low-lying areas in the city. The two options available were the Leith Valley supply which was to be very expensive, or the Silverstream supply which would be cheap and effective but would supply water to only the low levels.
In December 1877, during the on-going debate over the two systems there came a dry spell and Ross Creek Reservoir was so low that a fire in the city drained the reservoir. This incident served to motivate a decision and in December 1877 the Silverstream project was decided on.
By 1880 13 miles of water race was constructed out of a total of 18 miles and in 1881 it consisted of 29 km of winding open earth ditch 3 to 4 feet across, timber sluices, tunnels, weirs and steel pipes. It began at the top weir on Silver Stream and wound around the western slopes of Swampy Summit, Flagstaff and Three Mile Hill to the Southern Reservoir in Kaikorai Valley. It was opened on 15th December, 1881. All eastern tributaries of Silver Stream from the top weir to the Three Mile Hill Road were diverted into the open race by small masonry inlets.
Water shortages still recurred from time to time and it was soon found that the Silverstream scheme was not as wonderful as previously thought. In times of heavy rain the open water-race could not cope with the volume of water while there was not enough storage at the Southern Reservoir for a long period of heavy draw-off.
In 1895 it was decided that additional pumping and storage was required. The final location for a pumping station was at Powder Creek. In 1920 an electric pump was installed at the bottom weir, pumping water up a pipeline and into the water-race when needed. Apart from in 1890, it was not used again until 1928. By 1933 the population growth and the increase in water use made it practical to appoint a full-time attendant at the pumping station.
Since the early 1940s, land subsidence and the need for constant maintenance resulted in much of the open water-race being replaced with pipeline. The water-race in this area of tracks was the only major part that was not piped. Following a severe flood in 1957, the water-race above the pumping station was closed. After this, water for the race was pumped from the pumping station directly up the hill into the open water race.
The Silver Stream Water-Race was abandoned in the late 1960s. The current pumping station moves water along a buried pipeline following a new route to the Southern Reservoir.
In the late 1980s the Track Clearing Group began to re-open and develop the Silver Stream Water-Race Tracks. This group, with the assistance from the WEA over 50s Tramping Club continues to do great work in maintaining these tracks. The late Steve Amies was the founder of both groups and instrumental in re-opening the tracks.
Other matters receiving attention during this time were the afforestation of the water reserves and the detection and prevention of pollution. Considerable planting was done around the Leith and Silverstream catchments. The aim of this policy was commercial as well as functional. It was claimed that afforestation kept down noxious weeds, kept the area free from stock and rabbits, and increased the efficiency of the area as a water catchment as well as increasing the beauty of the country.
Since 1948 the open water race has been progressively replaced with a pipeline. The catchment lies to the West of the Flagstaff-Silverpeak divide, and comprises 4275 hectares which is largely council owned with much of it in native bush, some in tussock and some in exotic plantation.
– Adapted From City Forests Ltd hard copy information sheet and DoC Silver Stream Water-Race Tracks.
