|04- Water Tunnels|
A little-known aspect of subterranean Sydney is the network of high pressure pipes through which the Sydney Hydraulic Power Company once supplied the force to drive lifts, operate wool presses, and even open bank doors around the city and inner suburbs. Today, the only remnants of the company's operations are the pipes, which are still lying unused in the ground and are dug up every now and again by the various public utilities that dig holes in the road to lay their own lines.
The date 30 June 1975 marked the end of eighty-four years of operation by this unique public utility. Incorporated in 1889 as the Sydney and Suburban Hydraulic Power Company Limited it had, since. 1891, provided a multitude of businesses in the Sydney city area . with an extremely reliable source of power. The service extended from Grace Bros, Broadway to Pyrmont wharves on one side and almost to Garden Island on the other, through almost thirty kilometres of ten-centimetre and fifteen-centimetre mains.
The exploitation of high pressure water as a means of providing power was not restricted to goods and passenger lifts. Indeed, it has been used in a wide variety of applications, including cranes operating from the exterior walls of buildings, wool dumping presses, sprinkler systems, bank doors, sump pumps and a variety of motors. In the first instance, water for the power supply was taken from the city water supply system through a fifteen-centimetre main. The cost of obtaining water from this source proved prohibitive, and a dam was erected above a natural water supply on the five hectares of land lying between Mount Rennie (Moore Park Golf Course) and Waterloo, to provide a storage capacity of some 3 375 000 litres (which was later increased to approximately 4 500 000 litres. A low pressure pumping station, capable of delivering 112 500 litres per hour, was then built and connected to the just-completed Pier Street pumping station via four kilometres of 25-centimetre main. The water from the dam was pumped into a cast iron tank that formed the roof of the Pier Street pumping station measuring fifteen by twelve by three metres deep, and capable of holding some 675 000 litres.
In 1920, the Waterloo pumping station was converted to electric operation. The original steam pump was retained as a standby unit until the early 1950s to supplement the electric pump which, despite many overhauls, was in use until 30 June 1975.
By 1922 the demand for hydraulic power had become so great that substations were built in Cowper Wharf Road, Woolloomooloo, and at No.19 Wharf, Pyrmont, to cope with that extra demand imposed on the service, particularly by the many wool dumping preikes in the immediate vicinity of those substations. As a result of increased activities in the electric lift field, the original company name was changed in 1926 to Hydraulic Power
Electric and Hydraulic Lifts
Under the private Act of Parliament governing the company, the Council of the City of Sydney had the right. at the expiration of specified ten year periods. to take it over. The directors realised that should the Council exercise its right,-it could wholly acquire the company. Accordingly, since the electric lift section was producing at greater return than the hydraulic power side, it was decided to form a holding company (Hydelec Holdings Limited) with the subsidiaries Elevators Pty. Ltd. and Hydraulic Power Pty. Ltd. The registration of these new companies was finalised in January 1955, and, in January 1960, both companies joined the Lend Lease Corporation.
1952 saw the original steam plant, installed in the Pier Street pumping station in the 1890s wholly replaced by electrically operated equipment capable of meeting the then requirements of approximately 234 million litres a year.
In fact, one of the old steam pumps was dismantled and replaced in 1924 by a centrifugal pump capable of greater output. The last time the remaining steam pumps operated was during an emergency in 1943. Under wartime regulations the company was classified as a public utility and arrangements made so that an electricity supply should always be available. One morning the supply was unexpectedly cut off before there had been time to raise the accumulators to the appropriate height to give adequate pressure. With only a few hours in which to provide sufficient head for pressure, the old boiler was stoked to full pressure, and despite its age, worked immediately. It prevented a disastrous shutdown.
The dam at Waterloo remained the prime source of supply until 1968 when it was filled and the area used for bulk storage, as well as for car parking facilities for Elevators Pty. Ltd. By this time the demand for hydraulic power had decreased significantly due mainly to high rise development within the city. A bore was then sunk adjacent to the Elevators Pty. Ltd. test tower that was capable of delivering some 45 000 litres per hour. Its capacity had, by the end of June 1975, diminished to such an extent that under certain circumstances water again had to be purchased from the city supply to maintain adequate pressure, even for the few remaining units still in use.
The hydraulic power supply was terminated in three stages: stage 1 being the area bounded by Millers Point, Martin Place and Macquarie Street, closed down on 30 June 1974; stage 2 (closed down on 31December 1974) included that area lying between Martin Place and Druitt Street. The final stage was all customers south of Druitt Street and terminated on 30 June 1975.
Thus Sydney's unique hydraulic power system was closed down completely.
Sydney's first source of water, the Tank Stream is now a dark stormwater drain beneath the city. Busby's Bore is a sealed and scarcely remembered tunnel.
The Botany Swamps, Sydney's third source of water, have mostly been filled in for use as golf courses or for Sydney airport. The Upper Nepean Scheme built in the 1880s was a major engineering feat in its day,. Its 100-kilometre length included twenty kilometres of tunnels. Later pressure tunnels had to be dug through sandstone to distribute water to the growing population.
The Lachlan Water Tunnel, better known as Busby's Bore, was Sydney's first piped water supply. The tunnel was cut by convicts mostly through solid rock between 1827 and 1837, and supplied Sydney with water for nearly sixty years.
The water was drained from the Lachlan Swamps (now Centennial and Queens Parks) and flowed by gravitation under what is now the Sydney Showground, the Sportsground and Victoria Barracks -thence in a north-westerly direction below Oxford Street.
It surfaced near the corner of Liverpool and College Streets and continued diagonally across Hyde Park in elevated wooden pipes to an outlet point near the corner of Elizabeth and Park Streets -about where the Ladies Rest Rooms now stand.
The tunnel is no longer used but it is still mostly intact. There is an entry shaft at Victoria Barracks and you can still walk through parts of the tunnel if the water level is right. However, the springs which fed the original supply are still there and tend to fill up the tunnel for most of the year. Seepage from the tunnel is drained off into the Bondi sewer under Oxford Street near College Street.
In 1934 the Water Board's inspector Lewis was overcome by gas given off from the sedentary black mud which he disturbed while inspecting the stretch of tunnel between Riley and College Streets. He revived after two hours resuscitation at Sydney Hospital.
People have been throwing things into Busby's Bore for a number of years. In 1849, a cartage contractor was fined 4s.6d. for dumping 200 tonnes of nightsoil near the mouth of the tunnel. In 1910, workmen at the showground polluted the Botanic Gardens water supply by shoving cattle droppings into one of the shafts as an easy means of disposal. During the first World War dissident soldiers tossed their rifles down one of the shafts in protest. In 1979, the Royal Agricultural Society decided to restore one of the shafts as an historical feature. They located one under the Slippery Dip in Sideshow Alley hut work was held up because they found it had been filled with earth and rubble to stop the surcharge that had been flooding the nearby horse stalls.
John Busby, the man whose name the tunnel bears, arrived in the colony from England in February 1824, as Mineral Surveyor to the Government. He recommended that water from the Lachlan Swamps (now Centennial Park) be delivered by a tunnel or "bore" to a fifteen-million gallon (sixty-seven million litre) reservoir at the Racecourse (now Hyde Park). The tunnel, but not the reservoir, was approved, and legislative authority for construction and maintenance was given by the first Water Supply Act of Australia, the Water Tunnel Act passed in 1833.
Work on the tunnel started in September 1827, at the south-eastern corner of Hyde Park. Because of the unmanageable and unskilled nature of the convict labour and unforeseen difficulties in the strata, the tunnel was not completed until 1837, when Sydney was again in the grip of a prolonged drought. As work had proceeded, however, seepage springs were tapped and in 1830 these began to supply sufficient drinkable water to the public by means of a pipe carried on trestles a short distance into Hyde Park to facilitate the filling of water carts. Later, in 1833, the water was carried in pipes to the port for the use of shippage and sold at one shilling per' ton.
The bore was a little more than three kilometres long and averaged 1.5 metres high and
1.2 metres wide. It had twenty-eight vertical shafts ranging from six to eight metres deep. The removal of 204 774 cubic metres of spoil, mostly rock, was involved, and the whole project is reputed to have cost £24 000.
Much of the tunnel went through solid rock, and convicts toiled with pick and shovel within the confined passageway. When the diggers struck sand the walls of the tunnel had . to be cemented and lined with masonry from the rock quarries at Pyrmont. The completed tunnel delivered 1 300 000 to 1 800 000 litres per day, which was considered adequate for the population of Sydney, then 20 000.
A calamitous drought occurred soon after the tunnel was finished and extended from early in 1838 to May 1839. The supply through the tunnel became scanty and the Herald of 5 November 1838 recorded that:
Great distress exists in Sydney, especially at the northern end, in consequence of the scarcity of water. The stream from the pipes at the Racecourse is very small; so small that the men cannot fill the water carts without waiting four or five hours for a turn. Threepence per bucket is the price now asked, a heavy tax upon poor people.
The charge later was sixpence per bucket, with the normal charge one shilling per cask later reduced to sixpence, too. Connection to the bore was permitted for a yearly fee of ten shillings. In 1844 reticulation pipes for a water supply were laid from the tunnel to various parts of Sydney, about seventy houses being immediately connected. The annual charge made for the service. was five shillings per room. Public fountains from which water was drawn by all and sundry were established at various points in the town and proved "a great convenience". Two 225-millimetre diameter mains carried the water to various reticulation lines. One of these mains ran through Hyde Park to the top of King Street, and thence by that street to Clarence Street and Margaret Place; the other ran from Park and Pitt Streets to Hunter Street. In 1854, a small pumping plant was installed at the lower end of the swamp to increase the flow. dams having meanwhile been built at several points to conserve the-water. With this supplementation, Busby's Bore continued to be Sydney's sole source of supply until the Botany Swamps Water Supply Scheme of 1858. Early in 1872 supply from the tunnel almost ceased. In May of that year the tunnel was cleared from Hyde Park to the swamp -the first time it had been completely explored and measured since its construction nearly forty years earlier. More than 10 200 skips -1 473 dray loads -of debris, mostly sand, were removed from the tunnel during the five months between April and October 1872.
When it was cleared the tunnel was found to vary in size from about a one by one metre passage in some places to large caverns nearly three metres high. The line was very irregular and although its measured length was 3.3 kilometres, the surface distance was only
1.8 kilometres. Six blind or exploratory drives, all in a general south-westerly direction, were found between Moore Park Road and the tunnel mouth. They ranged in length from ten metres (the fourth drive) to 160 metres (the first).
The fourth drive had a branch drive for 5.2 metres in a northerly direction. These irregularities seemed to confirm the popular belief that Busby, in view of the character and class of labour employed in driving the tunnel, supervised it from the surface. In this connection a journalist wrote in 1903:
Mr. Busby's workmen were all gentlemen under permanent engagement to the government, having been transferred to the Colonial field of labour by the Imperial Government, who were their former employers. These gentlemen were, in the main, most disagreeable. In fact, they were so disagreeable that Mr. Busby never cared to go down into the tunnel to direct the work. Instead, he had to rely on progress reports supplied by the less disagreeable members of his working staff. He could, therefore, only approximately fix the lines of the tunnel. His instructions were given in the light of the information supplied him. Whether the gentlemen below followed his instructions, or the lines of least resistance, does not appear, but the tunnel zigzags about and rises and dips in an extraordinary way. A fine ten years' work. Yet the water came through it all right and it served all requirements up to the installation of the Botany System.
The irregularities in the floor of the tunnel were removed and cast iron segments built in at various places, thus improving the flow considerably. When the tunnel was returned to
service in October 1872, there was a marked decrease in pumpage required from Botany to less than 27 million litres per week. In other words, the supply to Woolloomooloo and the lower levels of the city via the tunnel had been increased by nearly four million litres per day.
On the morning of 24 August 1881, the office of the City Engineer, Mr Trevor Jones, was besieged by an angry crowd of Woolloomooloo citizens, each with a small bottle of water smelling of carbolic. It was, the citizens thought, an attempt by the Council to disinfect them against the smallpox epidemic then raging. Investigation showed that rainwater had washed traces of tar from the newly-tarred tram tracks in lower Oxford Street and these washings had percolated into the tunnel and tainted the supply. Remedial measures included the laying of two twelve-inch cast-iron pipes within the tunnel from' Riley Street to Hyde Park. The tunnel was out of commission for three months.
In 1902, during a prolonged drought, various means were sought to conserve the available water supply. As a large quantity of water was required for the Botanic Gardens, an arrangement was made with the Chief Secretary's Department, under which the Board laid an 80-millimetremain from a junction in Busby's Bore in Oxford Street at the top of Yurong Street through the Domain to the Gardens. As the water could have been polluted, it was ultimately decided that it would be dangerous even to convey it into a separate garden supply in case children or adults might drink from the garden hose. The use of the water from the Bore was, therefore, confined to flushing the creek and ponds in the Gardens and replenishing them when necessary. In 1934, because of the risk of subsidence under the tram lines in Oxford Street, the portion of the Bore from the intersection of College, Liverpool and Oxford Streets to a point near Riley Street was filled in with sand blown in by compressed air and water jet.
This pump at Barrack Hill in Oxford Street, Paddington, was erected in 1868. It is the only surviving relic of the methods of supplying water from Busby's Bore. Residents in the district used to collect water in buckets from the pump.
THE UPPER NEPEAN SCHEME
By 1867 the population of Sydney and suburbs had so increased, and recurring dry seasons caused so much anxiety, that on 24September the Governor Sir John Young appointed a Commission to recommend a scheme to provide a reliable and plentiful water supply for the future. The result was the development of Sydney's fourth water supply known as the Upper Nepean Scheme -and the building of its initial stage between 1879and 1888 proved to be one of the major engineering feats of its time. In investigations extending over two years, the Commission collected a mass of evidence on proposals for supplies from the Grose and Colo Rivers, Burralow, Wheeney and Little Wheeney Creeks, Couridjah Lagoons near Picton, Georges River and its tributaries, the Warragamba River, the Upper Nepean River and from the Nepean River at Penrith. In 1869 the Commission finally recommended the Upper Nepean Scheme as having the qualities sought in all great water supply projects throughout the world. This scheme embraced the tapping of the headwaters of the Nepean River and its tributaries, the Cataract, Cordeaux and Avon Rivers. The catchment area of these streams consists of 89 874 hectares of country on the top of the South Coast range, extending from opposite Clifton on the north-west. It was described by the Commission as "entirely a sandstone country, of a barren intractable nature, and if not turned to account as a gathering ground for water, is never likely to be of much use for anything else". The Commission's recommendations involved the construction of:
-A weir across the Upper Nepean River at Pheasants Nest, just below its junction with the Avon and Cordeaux Rivers; the flow of these streams to be diverted into a tunnel to connect with the Cataract River.
-A similar weir across the Cataract River at Broughton's Pass to direct the intermingled waters of the four streams into a sixty-kilometre conduit (later known as the Upper Canal) consisting of a series of tunnels, open canals and aqueducts.
-A storage reservoir at Prospect.
-An eight-kilometre canal (now known as the Lower Canal) from Prospect reservoir, ending in a basin at Guildford (now known as Pipe Head reservoir).
-An eight-kilometre wrought-iron pipeline from the basin at Guildford to a service reservoir at Potts Hill, together with pipeline from that reservoir to the existing reservoir at Crown Street with a branch into a new reservoir to be built at Petersham. From these two latter reservoirs, the Nepean water was to be fed into the Sydney and suburban reticulation system previously distributing the Botany supply.
The Commission estimated the cost of its proposed works at £800 000. However, the Commission's proposals were not immediately adopted. After six years, during which a number of alternative schemes were promulgated from various sources and the population had grown to 180 000, the Government of the day decided to obtain an independent opinion. It engaged Mr W. Clark, an eminent civil engineer in England to advise it on the water supply and drainage of the City of Sydney. Clark arrived on 29 November 1876, and, after considering eight schemes, recommended on 15 May 1877 the Upper Nepean Scheme at an estimated cost of £1 086 768. Endorsing the Commission's preference for a reservoir at Prospect, he also recommended that the capacity of the proposed Petersham reservoir should be increased and that additional reservoirs be provided at Newtown, Woollahra, and Waverley:
An Appropriation Act passed in July 1879 authorised a public works' loan, including £1 086 768, for the Upper Nepean Scheme. Work began in the following year, and the whole scheme was completed in 1888 at a cost of £2 076 313.
The total length of the completed work was 100 kilometres including twenty kilometres' of tunnels and fifty kilometres of canals.
Distribution to Sydney and suburbs south of the Parramatta River and Sydney Harbour begins at Potts Hill reservoirs. In 1888, when the Board assumed control, water was carried from Potts Hill through a single line of cast-iron pipes to a branch connected with a reservoir built at Petersham, and continued on to Crown Street reservoir. From here, water was pumped to reservoirs at Paddington and Woollahra, and from Woollahra to a reservoir at Waverley. From these reservoirs the water was distributed through about 600 kilometres of arterial and reticulation mains to the city and twenty-three suburban districts.
A second main pipeline from Potts Hill to Crown Street became necessary almost immediately. It was constructed by the Harbours and Rivers Department (then the constructing department for water-supply works) and was transferred to the Board in 1893.
As the western suburbs developed it was necessary to provide further branches. By the summer of 1911 the mains were barely able to cope with peak consumption. A major means of relieving the situation and providing for future development was the construction of a large pressure tunnel between Potts Hill and Waterloo pumping station.
Investigation was begun in 1914, the desired delivery capacity being 450 million litres per day. This would have required eleven 120-centimetre mains if laid near the' surface without boosting -and the interference with roads, buildings, subways, sewers, and various other services, would have been unthinkable. The alternative, a pressure tunnel deep beneath the surface, was approved by the Board in 1915.
The tunnel was to extend from Potts Hill reservoir to the Waterloo pumping station, a distance of sixteen kilometres.
Trial bores were put down during 1921 and 1922. Preliminary work began in 1923. he first operations involved the sinking of seventeen shafts. The shafts were completed by June 1925, and the driving of the tunnel by two headings at each shaft commenced.
In August 1924, the Board bought two Arrol-Whittaker tunnelling machines of a type used successfully for similar work at Bournemouth and Manchester in England. The machines, delivered in June 1925, proved entirely unsuitable for the task because of the nature of the sandstone and its effect on the cutting tools. They were ultimately withdrawn, and driving was resumed by manual labour. The first drive was completed in August 1925. Other sections quickly followed, and the driving of the tunnel was completed by February 1927.
The tunnel lining, of sandstone concrete more than forty-five centimetres thick, was placed by a Webb concrete gun, installed and operated for some months under the supervision of the patentee, Mr W. Webb. President of the Universal Concrete Gun Co. of USA. The concrete was brought to the gun in trains of four one-cubic yard trucks hauled by battery-operated electric locomotives. The lining was finalised in 1928, as also was the connection between the outlet tower of Potts Hill reservoir and the inlet shaft of the pressure tunnel.
Preparations were made in July 1929, to check the safety of the tunnel before using it. Six heavy steel bulkheads, carried on especially constructed reinforced concrete rings, were provided to divide the line into six sections. The first test was made from Potts Hill No. 1 shaft to No. 5 shaft, a length of four kilometres of the deeper section of the tunnel. The results were satisfactory up to a head of 120 millimetres. When the full head was applied, however, there was an extensive rupture of the lining over a length of 210 millimetres where dykes and poor quality rock had been met.
Although an appreciable quantity of water was escaping, it was decided to place this section of the tunnel in commission immediately because of the urgency of increasing the supply to Sydney. The section was used throughout the summer of 1929-30 to supply the Lakemba pumping station.
When further fractures developed during the testing of the tunnel between shafts 6 and 9, it was decided that remedial measures were necessary. Subsequently, in June 1930, the Board approved of lining the tunnel for its full length with steel tubes. The space between
the tube and the tunnel was to be filled with bluestone concrete.
The Botany Swamps pumping station. The plant was dismantled in 1896 but the chimney stack was for many years used as a sewer vent shaft. Much of its upper portion was demolished during the extension to Kingsford-Smith Airport.
In February 1931, a start was made in placing the steel liners. After extensive tests between January and May 1934 on the section between shafts 1 and 6, the committee reported that the results were highly satisfactory and that it believed the measured leakage to be far less than that ever recorded from a pressure water conduit of such size. The Potts Hill-Sydney pressure tunnel was the third largest in the world. Both the Ritom tunnel in Switzerland and the Moodna-Hudson (New York) tunnels ruptured at trial fillings. The second section of the tunnel between shafts 7 and 17 (Ashfield to Waterloo) was lined with the steel tubing by September 1935, and after equally satisfactory tests the full length of the tunnel was placed in commission in November 1935. During May 1936, it was de-watered and closely inspected by the Testing Committee, which found the entire length of sixteen kilometres in very satisfactory condition.
In a paper on the construction of the pressure tunnel, Mr G. Haskins stated that experience had proven that:
-Sydney sandstone is not in itself a suitable medium for carrying high-pressure water in underground tunnels; -an unreinforced sandstone concrete has little, if any, value as an impervious lining against the considerable hydrostatic pressure for which the Sydney pressure tunnel was designed;
-the leakage through such lining results in high-pressure pockets in the rock strata surrounding the tunnel, with consequent risk of rupture and leakage: and
-any conduit of this nature constructed in sandstone must have an impervious lining of sufficient strength and elasticity to withstand the full hydrostatic pressure to which it may be subjected.
The failure of the Sydney pressure tunnel under test was investigated by a Royal Com-mission, which sat from November 1932 until May 1933, and reviewed several matters connected with the Board's activities. This Commission attributed the failure of the tunnel under test to incorrect design and location, but agreed that the remedial measures would be satisfactory from the point of view of safety. With the pressure tunnel eventually running to its full capacity, an additional tunnel became necessary and, when a schedule of post-war reconstruction works was prepared at the request of the National Works Council in November 1943, the Board gave high priority to a second tunnel. On 13 February 1946, construction of this tunnel was approved. On 26 April 1946, work began on the excavation of shaft No. 5. All shafts were completed by 22 December 1949, with the exception of shaft No. 13, excavation of which was not started until May 1957. It was completed on 28 October 1957. Beginning at Potts Hill, the tunnel passes under Chullora, Bankstown, Enfield, Canter-bury, Ashfield, Petersham, Marrickville, Erskineville, and Waterloo at a depth below ground-level varying from fifteen metres to sixty-five metres, the latter under high ground at Ashfield. Its maximum grade is 1 in 100, and its minimum is 1 in 2000. Of its total length of sixteen kilometres, approximately 8000 metres was driven in sandstone, 7000 metres in shale and the remainder in a mixture of both materials.
UNDER THE PARRAMATTA RIVER
The north side of the Harbour had its own water problems. To meet the ever-increasing demand for water, the construction of a third line of pipes was commenced 'n 1924, the route of the main following as direct a line as possible between Pipe Head add Ryde and crossing the Parramatta River. It was decided to cross the river by tunnel rather than by bridge. By 1925, the pipeline was completed except for the crossing. Boring for the proposed tunnel under the river having been completed by the Mines Department, shaft-sinking was commenced in the latter part of 1926, and the final section
of the main above ground was laid across the swamp on the southern side of the river to the commencement of the tunnel crossing. By the end of 1928, the tunnel and shafts had been completed and lined by concrete, and connection made to the main on both sides of the river.
When the tunnel was placed in service, defects became apparent and it bad to be dewatered. Examination revealed serious ruptures. Some months were spent in sealing-off the inflow of river water by grouting, and this was finally reduced. It was clear, however, that the inflow could not be permanently stopped without more drastic treatment, so it was decided to insert an inner lining of flanged steel cement-lined pipes in both the tunnel and shafts and completely fill the space between the tunnel walls and the steel lining with concrete. This work was completed in 1929.
|This section is based on the excellent book by Brian and Barbara Kennedy. (Subterranean Sydney (The Real Underworld of Sydney Town), Reed, Sydney, 1982. ISBN 0 589 50312 X). Copyright Brian and Barbara Kennedy and Reed Publishing.|