Dec 11 1980

Dunedin’s Water Supply

The first settlers drew their water from the creeks and springs in the area below the Town Belt, the principal sources being the Maclaggan Street, London Street and Regent Road creeks. In 1860 the Town Board tapped a spring in High Street and erected a public pump at the Manse Street corner.

A private waterworks company was mooted in 1863 and a public company was formed in 1864. The scheme was designed by the Company’s engineer, Ralph Donkin, and after many trials and tribulations the reservoir, now known as Ross Creek was completed. The Chairman of the Company, John Bathgate, name it the Royal Albert Reservoir and water was turned on on 9 December 1967. The occasion was something of an anti-climax because of a break in the main.

There was continuing friction between the City Council and the Company and the City finally took over the system in 1875.

The only area served was that below the Town Belt and it was not long before further water was required here as well as for the boroughs on the hills above.

The headwaters of the Silverstream and the Waitati-Leith became rival sources of supply and it is recorded that one day in November 1877 the Council set off on horseback to inspect the rival sites. Not all covered the whole course! In the face of severe shortage following drought and a major outbreak of fire, the Council decided in December 1877 to proceed with the Silverstream supply. There was much dissatisfaction from the hill boroughs which could not be served by this supply but construction of the 18 mile SIlverstream Race and Southern Reservoir proceeded and this system was officially opened in 1881. The supply was brought to the City via the old Caversham railway tunnel.

Considerable debate continued on the question of supply to the hill areas and there was doubt about the wisdom of constructing a reservoir in the upper Leith, sitting as it would above the City itself. However water was brought in from the main tributaries of the Leith by pipeline by 1904 and  reticulation of Maori Hill, Roslyn and Mornington could proceed.

The much-debated dam at the head of the Leith finally went ahead and was completed in 1916. It was name after Mr A J Sullivan, the Chairman of the Water Committee when the project was authorised.

Proposals for bringing water from Lee Stream were advanced about this time but did not proceed and the next major step was augmentation of the Sinverstream supply by installation of a pumping station at Powder Creek above Whare Flat in 1920.

The next year a poll of ratepayers turned down by a large majority a 160,000 pounds scheme to bring in water from Lee Stream.

in 1923 the capacity of the Southern Reservoir was increased from its original cubic metres to its present 295,500 cubic metres.

There were no major moves on water supply until Mr J G Alexander, then City Engineer, reported in 1929 in favour of using the Deep Stream rather than Lee Stream and bringing 23000 cubic metres per day from an intake a few miles upstream of Rocklands Station. Unfortunately, the Council – in  those depression days of the early 30s – turned this down and a modified scheme of less than half this capacity and drawing from Deep Creek, a high level tributary of Deep Stream, was authorised by poll and work commenced in 1934. It was commissioned in 1936 and could serve suburbs more than 300 metres above sea level.

In the late 1940s the supply position was again serious. Some minor additions were made to the catchments and a deep bore at Wingatui provided some temporary relief. This bore water had a very high iron content and was unsuitable for permanent supply. After lengthy consideration between 1947 and 1951 of various alternatives – development of reservoirs in the Silverstream, supply from Deep Stream, from Waipori and from the Taieri – the scheme to draw 23,000 cubic metres per day from bores near the Taieri River upstream of the Outram bridge won Council approval in 1951. The scheme was completed in  1956.

By 1967 it was becoming apparent once again that the City’s water supply system would not be able to meet increasing demands in the foreseeable future. After a period of investigation and planning, construction of the Deep Stream Water Supply Scheme was commenced in 1971 and completed in 1977.

The Dunedin City Council supplied, treated and distributed water to consumers in Dunedin City. The only areas at that time excluded from the supply were undeveloped areas, mostly at high levels, and some parts of the Otago Peninsula. In addition, treated water was supplied in bulk to the Boroughs of St Kilda and Green Island. Reticulation in those areas was the responsibility of the Borough concerned.

A bulk supply of treated water was also extended to Silverpeaks County, which distributed it to consumers in the Wingatui, Fairfield and Waldronville areas.

The Ross Creek storage reservoir at 115 m above sea level held 227,000 cubic metres and was fed from a 364 hectare catchment when comprised Ross Creek, Nicols Creek and the lower part of Morrison’s Creek. The catchment was uninhabited, Council owned and in native bush and tussock.

The dry weather yield of the catchment compared favourably with the adjacent Waitati-Leith catchment. The average rainfall at the Reservoir was 1040 mm per year, and of this, some 30% was collected.

The Waitati-Leith Catchment covered 790 hectares on the eastern side of the Flagstaff-Swampy ridge. It provided the greatest quantity of water at the lowest unit cost of any of the City’s water sources. The significant factor in the effectiveness of this source was Sullivan Dam, which impounded 136,000 cubic metres at an elevation of 297 metres above sea level near the head of the Leith Valley. The annual rainfall at Sullivan Dam averaged 1250 mm. Nearly half of this precipitation on the catchment was collected, treated and distributed to consumers in the City. The catchment was uninhabited, Council owned and covered with native bush and tussock.

-From two pages of typing in Leader’s file.

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