Celebrating 125 years of the 125 years

s the Upper Nepean Scheme that water to to provide far away from a city, transported Acelebrates its 125th anniversary, a reliable supply. by canals and pipelines, and stored it’s remarkable that so little is known The solution that was completed in a major . It would also require by Sydneysiders about such an in 1888 was ingenious: two weirs no energy – water would simply important piece of infrastructure on the Upper Nepean rivers collect flow by gravity. that once saved Sydney from water which is sent by gravity It was a scheme of many firsts drought and continues to supply along a series of tunnels, canals in Australian engineering and water more than a century later. and aqueducts to a large water supply history and in this The vision for the scheme was simple in Sydney’s west, from where it flows commemorative publication yet far-sighted: collect water on the by gravity to the city and suburbs. we celebrate the remarkable Southern Highlands where it rains It was the first time in achievements of those who planned, frequently and heavily, and transfer that water would be collected designed and built the scheme. Celebrating 125 years of the Upper Nepean Scheme

The Upper Nepean – a scheme of firsts

(Continued from front cover) Barely a decade after its completion in 1888, Sydney ran dangerously For all its simplicity and ingenuity, low on water during the Federation the Upper Nepean Scheme still drought in 1901-02. needed to be funded and constructed. It took two major government Fortunately, the scheme’s original inquiries over 13 years before funding design lent itself to progressive was allocated and work finally started expansion. As Sydney’s population in 1880. It was then built in just grew from 296,000 in 1888 to nearly eight years. 1.5 million in 1939, four new Engineering of the highest standard were built on the Upper Nepean to was required to build the tunnels, supplement the scheme’s supply. canals and aqueducts, because the Seventy-eight years have passed since gradient was so small and yet water the fourth dam was added to the needed to flow by gravity all the Upper Nepean Scheme, during which A scheme of firsts: way to the city. time Sydney built , •  The Upper Nepean Scheme – one of the world’s largest domestic was another Sydney becomes first Australian water supply dams. engineering feat. Not only was it city to harvest water far from Australia’s first dam with an earth fill Yet even today, the Upper Nepean the city and transfer it by canals and rock embankment, it is still an Scheme continues to supply 20 to and pipelines, and store it in a impressive example of such a 40 percent of Sydney’s water. major dam. reservoir even by today’s standards. Water continues to flow along the • Upper Canal – unique example Before the canals or the reservoir Upper Canal to Sydney, just as it did of nineteenth century hydraulic could be completed, Sydney was 125 years ago. Prospect Reservoir engineering in Australia, using again gripped by drought in 1885. remains an important part of the canal building techniques often An enterprising engineering firm water supply system. at very small grades, relying only on gravity. temporarily connected the missing And the engineers and workers who • Prospect Reservoir – Australia’s links in the scheme to provide an designed, built and maintained first earth fill and rock emergency supply of water within the scheme over the past 125 years embankment dam, and still six months (see inside story – continue to deserve our thanks for one of the largest. Hudsons’ temporary scheme). a job well done. But the story of the Upper Nepean Scheme’s ingenuity Above: The blue ribbon of the Upper Canal had only just begun. as it winds its way between Appin and Campbelltown. (Photo: A Hollingsworth)

Left: Pipelines and aqueducts had to cross gullies and rivers to ensure the water could flow by gravity all the way to Prospect Reservoir.

Cover image: The men who constructed Leafs Creek Aqueduct pose for the camera. This photo was taken sometime between 1886 and 1888 by renowned Australian landscape photographer Charles Bayliss and is one of the few images we have of the workers on the Upper Nepean Scheme. 125 years later, the Bayliss family connection continues with the SCA’s own Steven Bayliss, South East Operations Coordinator, overseeing Upper Canal transfers and operation of the Upper Nepean dams. Page 03

How it worked

STAGE 2 – BUILT 1902-1935 STAGE 1 – BUILT BY 1888 NEPEAN SYSTEM

NEPEAN RIVER

NEPEAN DAM

PHEASANTS NEST WEIR

AVON DAM PROSPECT RESERVOIR LOWER CANAL NEPEAN TUNNEL DAM WEIR

BROUGHTONS RESERVOIR PASS WEIR CANAL\PIPELINE TUNNEL CATARACT RIVER RIVER CATARACT UPPER CANAL TUNNEL

How it worked in 1888... The entire 64-kilometre length of ...and Stage 2 open canals (44km), tunnels (19km) Rainfall on the Plateau south Construction of the four Upper and aqueducts (1km) is known as of Sydney flows into the Cordeaux, Nepean dams between 1902 and the Upper Canal. Cataract, Avon and Nepean rivers. 1935 essentially did not alter how the From Prospect Reservoir, water flows A weir at Pheasants Nest, just below Upper Nepean Scheme worked – it by gravity along the 7.7km Lower the junction of the Cordeaux and simply increased the amount of water Canal to a basin at Guildford (known Nepean rivers, diverts some of the the scheme could reliably supply, by as Pipe Head), from where it is piped water into the 7km Nepean Tunnel storing water in upstream dams rather to a service reservoir at Potts Hill, which travels under the town of Wilton than relying solely on river flows. near Auburn. and connects with the Cataract River. Water from Avon, Cordeaux and From Potts Hills Reservoir water is A second weir on the Cataract River Nepean dams flowed to Pheasants piped to the , at Broughtons Pass diverts water into Nest Weir, where it was diverted via and a larger service reservoir at the 3km Cataract Tunnel. the Nepean Tunnel to Broughtons Pass Petersham. Weir. Water from Cataract Dam flowed Water emerges from the Cataract From Crown Street and Petersham directly to Broughtons Pass Weir. Tunnel into a canal at Brooks Point, , Upper Nepean Scheme near Appin and then continues to From Broughtons Pass water flowed water is supplied to the city and flow by gravity to Prospect Reservoir. through the Cataract Tunnel and suburbs previously supplied with Upper Canal to Prospect Reservoir – water from the Botany Swamps as it did before construction of the Scheme. Upper Nepean dams. The Lower Canal was replaced with a tunnel and was decommissioned in the 1990s. The Upper Canal continues to flow by gravity, as it has done for 125 years. Celebrating 125 years of the Upper Nepean Scheme

Built for our ‘health, comfort and prosperity’

ong before Warragamba Dam, Lthe Upper Nepean Scheme was the jewel in the crown of Sydney’s water supply. A Royal Commission recommended the Upper Nepean Scheme to “make Sydney the best watered of Australian cities, as it is at present the worst; and will minister to the health, comfort, and prosperity of its inhabitants to distant times”. Although the scheme needed to be expanded almost as soon as it was completed – with four major dams built in the early 1900s in addition to the two original weirs – it remains an important part of Sydney’s water supply today. Until the Upper Nepean Scheme was completed in 1888, the early settlers relied on local water supplies – originally the , then swamps near Centennial Park and . The early British settlers knew little about conserving or storing water, coming from a place where rivers always flowed and it rained all year round. Nor did they understand much about protecting the water from contamination which could also reduce the supply of drinking water. As a result the colony was regularly on the verge of running out of water. Illustration of the Upper Nepean In 1867, with a growing population, Scheme in the May 1895 ‘Town and frequent droughts, and continuing Country journal’ which celebrated public anxiety about water supplies, the transformation of Sydney’s the Governor appointed a commission water supply. to find a reliable and plentiful water supply for Sydney’s future. The five-person commission included Edward Orpen Moriarty, Engineer- in-Chief of Harbours and Rivers for the Public Works Department from 1858-88, and the man credited with the design and execution of the Upper Nepean Scheme. Edward Orpen Moriarty, Engineer-in-Chief of Harbours After two years’ investigation, the and Rivers, led the design and commission recommended collecting development of the Upper water from the 1,000 square kilometre Nepean Scheme. Page 05

Upper Nepean catchment south of Sydney, and transferring it through A daring emergency scheme to 64 kilometres of tunnels, canals and pipelines to a huge new reservoir at rescue Sydney from water famine Prospect. From there it would flow Hudsons’ Temporary Scheme by gravity along a Lower Canal to Guildford where it would connect with Before the Upper Nepean Scheme eight creeks in rugged locations and the city’s existing water supply system. could be completed, Sydney was crossing the Great Southern Railway gripped by another drought. In 1885 line near Menangle. More than a decade passed and the Lachlan and Botany swamps Even more remarkably, between the another inquiry was held before the were down to about 10 days’ supply Lower Canal at Guildford and Botany Upper Nepean Scheme was confirmed and the city council asked the they built three kilometres of open as the best solution to Sydney’s water government for urgent help. timber fluming on timber trestles, needs, and work finally began in 1880. With Prospect Reservoir only half some of them 21 metres high. Then in 1885, before the scheme was finished, the Upper Canal still On 30 January 1886, the Mayor of completed, Sydney was gripped by unconnected by pipes across Sydney and the Minister for Public another major drought. With only gullies in many parts, the situation Works officially turned on the flow of 10 days’ supply remaining, urgent was desperate. Nepean water into the Botany lakes. action was required (see ‘Daring The Minister for Public Works seized Hudsons’ Temporary Scheme emergency scheme’ story opposite). on a daring temporary solution continued to operate for several In 1888, the first stage of the Upper proposed by a local engineering more years until the Upper Nepean Nepean Scheme was completed and firm, the Hudson Brothers (who later Scheme was completed as planned water finally flowed from the Upper became Clyde Engineering, now in 1888. It was dismantled soon after, Nepean weirs along the Upper Canal part of Downer EDI). ending one of the most colourful to Prospect Reservoir to supply the The Sydney Morning Herald chapters in the history of Sydney’s city’s needs. reported on 29 May 1885: water supply. That same year the Board of Water “Mr H. Hudson had suggested to However, for more than two years Supply and Sewerage was established the Government that the gaps in Hudsons’ Temporary Scheme served to manage all water supply and the ‘waterworks’ between gorges a noble purpose, as the Sydney sewerage infrastructure owned by should be connected by timber Morning Herald reported on 1 government and city councils. fluming, and that he guaranteed February 1886: bringing 3,000,000 gallons of water Today, manages treated “The real merit of the work consists a day to the Botany Dams at a cost water supply and sewerage. The Upper in it having removed all danger of of 60,000 [pounds].” a water famine.” Nepean Scheme and Sydney’s other That’s 13.6 million litres of water a major dams and raw water supply day in today’s measurements all infrastructure are managed by the delivered to Botany Swamps within Sydney Catchment Authority. six months – a mighty promise to As for the Upper Nepean Scheme, deliver on! 125 years after it was completed With its back against the wall, its legacy continues as a valuable the government immediately part of Sydney’s water supply. commissioned the scheme. Indeed, the Upper Nepean Scheme In just six months of frantic has lived up to predictions that it construction activity, the Hudson “will minister to the health, comfort, Brothers built 16 small concrete and prosperity of its inhabitants to dams along the Upper Canal and laid distant times”. 1200 giant cast iron pipes, bridging

The Hudsons’ Temporary Scheme is shown here as the smaller pipe running alongside the large, permanent Upper Nepean Scheme pipeline. In 1888 the temporary infrastructure was dismantled. Celebrating 125 years of the Upper Nepean Scheme

The Upper Canal – an unsung hero of Sydney’s history

he Upper Canal is an unsung hero Where the ground is soft, the canal Tof Sydney’s history. A precise piece is trapezoidal in shape and the sides The maintenance men of engineering still serving the needs lined with unreinforced concrete of the Upper canal of Sydney 125 years later. slabs. In other sections, the canal is For nearly a century, the Upper Built in the 1880s, now listed on the u-shaped and the sides are lined with Canal was maintained by men State Heritage Register, the Upper sandstone masonry. Where the canal who lived in isolated cottages Canal is still the only way of transferring is cut into solid rock, it is unlined. along the canal. They walked or water to Sydney from the four Upper Tunnels allow the canal to pass under rode horses to patrol the length Nepean dams (Cataract, Cordeaux, hills. These are unlined if cut through of canal assigned to them, a Avon and Nepean). These dams supply solid rock, or lined with brick or length of about eight kilometres. on average 20 per cent of Sydney’s sandstone if cut through softer water, but at times can supply up to material. The cottages were phased out 40 percent of Sydney’s daily demand. Aqueducts allow the canal to in the 1970s and replaced with ‘Green’ before its time, it uses no cross creeks and gullies. These mobile maintenance teams. energy other than the earth’s gravity were inverted iron syphons resting When Garry Smith began on the to transport water 64 kilometres to on sandstone piers. canal 24 years ago, he was part Prospect Reservoir in Sydney’s west. In all, the Upper Canal has one of a team of 15 workers who “The canal drops just 50 metres in kilometre of aqueducts crossing nine travelled the length of the canal elevation over 54 kilometres after the creeks and the Southern railway line, each day. Now with the Sydney Nepean and Cataract tunnels – just nineteen kilometres of tunnels and Catchment Authority, Garry 0.1 percent grade – a marvellous feat 44 kilometres of open canal. supervises the contractors who carry out maintenance tasks. of engineering following the earth’s Many of the original iron pipes remain contours. It is a wonderful legacy left in use, some lined with plastic sleeves “Our main jobs were cleaning the to us by the engineers and surveyors to protect the pipes and keep them trash racks that collect leaves and of the late 1800s,” says Ian Tanner, waterproof. other floating debris, repairing Group General Manager, Assets and Many of the original mechanisms to fences, mowing, and removing Major Projects, with the Sydney control and divert the water’s flow – the occasional stray animal,” Catchment Authority. such as stop logs, penstocks, and Garry says. The canal is built from a variety of gate valves – are also still in use. “Cows and kangaroos were the materials, depending on the nature most common animals that of the country it passes through. would end up in the canal. We’d average one or two of each a year. We could usually rescue most of them safely. 1886 2012 “These days kids swimming illegally in the canal is the biggest problem. Suburbia is getting closer every year, and the canal is not as isolated as it used to be.” The Upper Canal occupies a continuous corridor between 15 to 50 metres wide. Public access is totally restricted for Construction of the Upper Canal in The Upper Canal as seen from a similar public health, water quality, 1886. The primitive huts which housed vantage point in 2012, located south security and safety reasons. the workers can be seen on the far right of Glen Alpine in Sydney’s south-west. of the photograph. Page 07

The Lower Canal –gone but not forgotten Arthur Streeton’s 1895 painting of the magnificent new Prospect Reservoir. emarkable for its impressive The painting is now part of the NSW Art Gallery’s collection. Rbrick aqueduct and very low grade, the Lower Canal connected Prospect Reservoir the new Prospect Reservoir to the city’s existing water supply system – the centrepiece at Guildford. Relying on gravity like the Upper rospect Reservoir was the of compacted earth placed in Canal, the Lower Canal dropped just Pcentrepiece of the Upper layers 30 centimetres thick, and 77 centimetres over its 7.7 kilometre Nepean Scheme when completed compacted by rolling. length – a grade of 1 in 10,000. It in 1888. After travelling 64 A stone roller of a type used in was another remarkable engineering kilometres from Pheasants Nest engineering works of bygone days feat for its time. Weir, water emptied into the giant was used to compact the earth. new 50,000 megalitre reservoir. The Boothtown aqueduct – built as Made from volcanic stone and part of the scheme – allowed the canal Located 35 kilometres west of the built in sections with an irregular to flow across a 225-metre wide valley. city, Prospect’s elevation meant that circumference, a team of 10 horses Its 22 brick arches, each with a span of water could continue to flow by was needed to pull the roller. nine metres, are still intact today. gravity all the way to Crown Street Known as Pincott’s roller, it is Reservoir in the city. After a series of structural failures in on display in the grounds of the 1890s, in 1907 the aqueduct was Prospect was the first earth fill and Prospect Reservoir. replaced with a three-metre wide rock embankment dam in Australia, inverted concrete syphon. Built in the and is still large by today’s standards. NOTE: Prospect Reservoir grounds will be earth bank beside the aqueduct, at The top of the embankment was closed to the public during the SCA’s dam upgrade works from 1 September 2013 to the time it was the longest continuous raised by half a metre in 1898. December 2014. These works will ensure concrete work of its kind in Australia. The embankment is 26 metres the dam meets the highest standards of The Lower Canal was decommissioned high and 2.2 kilometres long. It safety and continues to provide flexibility after a pipeline was completed in consists of a clay core with shoulders for Sydney’s water supply. the 1990s, and the bush reserve surrounding the canal opened to the public in 2003 as a cycleway. Today, you can walk or cycle along this unique parcel of bushland as it winds through a densely populated area of Western Sydney, and spot many reminders of the ground-breaking Upper Nepean Scheme and its Lower Canal.

The 22 arches of the spectacular Boothtown aqueduct still stand today in Greystanes and is a reminder of the former Lower Canal. Celebrating 125 years of the Upper Nepean Scheme

Changes over time

Features of the 1888 scheme Expansion of the scheme • Pheasants Nest Weir – 3 metre (1902-1935) high weir just below the junction A Royal Commission after the of the Cordeaux and Nepean rivers. Federation drought of 1901-02 • Nepean Tunnel – 7km tunnel from recommends expansion of the Upper the Nepean River under the town Nepean Scheme. Four dams are built of Wilton to the Cataract River at above the original two weirs which Broughtons Pass. do not alter the way the scheme works – they simply increase the amount of • Broughtons Pass Weir – 3.5 metre Cataract Dam, built by 1907 to expand water the scheme can reliably supply, high weir across the Cataract River. the Upper Nepean Scheme. by storing water in upstream dams (Photo: A Hollingsworth) • Cataract Tunnel – 3km tunnel rather than relying solely on river Improvements and from Broughtons Pass Weir to flows. Brooks Point, near Appin. maintenance (1935 to today) Cataract Dam 1902-07 • Upper Canal – 64 kms of canals, The main features of the Upper Nepean Created by damming the Cataract tunnels and aqueducts to Scheme continue to operate today just River, Cataract was the first of the four Prospect Reservoir. as they were designed. Upper Nepean dams. Together with • Prospect Reservoir – Australia’s Cordeaux Dam, Cataract supplies To meet modern dam safety standards, first earth fill and rock embankment water to Camden, Campbelltown Prospect Reservoir and the four dam, designed to store 50,000 and Wollondilly council areas via the Upper Nepean dams were upgraded megalitres of water at Prospect, Macarthur water filtration plant as between the 1970s and the 1990s. 35km west of the city. well as Prospect Reservoir. A tunnel linking Avon and Nepean dams, to enable the transfer of water • Lower Canal – 7.7 km canal from Cordeaux Dam 1918-26 Prospect Reservoir to a basin at between dams in either direction, Created by damming the Cordeaux was completed in 1973. Guildford, known as Pipe Head, River, Cordeaux was the second of In 2008 a $56 million Raw Water where Nepean water is connected four Upper Nepean dams. Together Pumping Station was built at Prospect to the city’s water supply system. with Cataract Dam, Cordeaux supplies Reservoir to create greater flexibility • Potts Hill Reservoir – service the Camden, Campbelltown and in Sydney’s water supply and to access reservoir built near . Wollondilly council areas via the an additional 28,000 million litres from • Petersham Reservoir – reservoir Macarthur water filtration plant as the reservoir. capacity increased from 3.6 to well as Prospect Reservoir. In the second half of 2013 the Sydney 9 megalitres. 1921-28 Catchment Authority will commence Created by damming the Avon Stage 1 of rehabilitation works for the River, Avon was the third and largest canal worth $9 million. This project of the four Upper Nepean dams. aims to reduce risks of failure for such Today, it’s main role is to supply the an important piece of water supply Illawarra region. infrastructure. Works will stabilise 1925-35 sections of the canal wall where Created by damming the Nepean it is vulnerable, increase security River, Nepean was the last and fencing, improve local stormwater smallest of the four Upper Nepean management, upgrade maintenance dams, but it has the largest access, rehabilitate inlet and outlet catchment. Today it supplies nearby points on the aquaducts and install Bargo, Thirlmere, Picton and The new penstocks, which control the Oaks, as well as the Macarthur and flow of waters. Prospect water filtration plants. These works will ensure the reliable supply of Upper Nepean water to Damaged photo from circa 1888 Sydney into the future. showing some of the surveying instruments used to mark out the route of the Upper Nepean Scheme.

www.sca.nsw.gov.au Sydney Catchment Authority (02) 4724 2200