Prospect Reservoir

1886 - 1888

Two timber flumes, constructed from Prospect to Botany.  Carried water into the Botany Swamps for use in the Botany - Lachlan Swamps, water supply system.

 

1888

Dam Wall suffered a series of slips in the earth wall. Concern due to the well-known Failure of the dam at Sheffield, England. Commission of enquiry set up.  Further slips in 1893, 1898, 1899 and 1982. Various remedial works carried out.

 

1905

Embankment finally stabilised.

 

1907

Construction of Cataract Dam as main storage reservoir made Prospect the principal service reservoir.

 

1926

Supply provided by lower canal exceeded by summer demand. Supplementary supply from the upper canal to the pipe head became a matter of urgency.

 

1927  

1400 mm wood stay main completed, capable of supplying 50,000,000 gallons a day to the pipe head.

 

1929

1800 mm steel main proposed to serve the same function with a branch connected to Prospect Reservoir.

 

1931  

Construction of steel main commenced, but halted due to economic depression.

 

1933

Project resumed providing jobs for the unemployed.

 

1937

Pipeline completed.

 

1946

Plans for Warragamba Dam approved.

 

1954

New 2100mm pipeline proposed to run alongside the 1800mm pipeline.

 

1959

New 2100mm pipeline completed.

 

 1960  

Chlorination facilities provided at prospect Reservoir.

 

1979

Dam strengthened by placement of stabilising beams on the downstream face.

 

1987

Construction of a new southern outlet completed and a connection to the 2100mm pipeline made.

 

1997  

Further stabilisation by placement of stabilising beings on the upstream face.

 

© Prospect Heritage Trust Inc.
Building Prospect Reservoir
PROSPECT RESERVOIR
In 1869 a Commission appointed by Governor Young recommended the Upper Nepean Scheme as the best solution to Sydney’s water supply problems. The scheme involved tapping the headwaters of the Nepean River and its tributaries, the Cataract, Cordeaux and Avon Rivers. A number of diversion weirs were built across the streams, which fed into tunnels, canals and aqueducts known as the Upper Canal, which carried the water to Prospect Reservoir. From Prospect the water was carried down the Lower Canal to a basin at Guildford, now known as Pipe Head. The city of Sydney finally received its water after it was piped from Guildford to a      
service reservoir at Potts Hill and from there to Crown Street and several other reservoirs around the city. Work on the Upper Nepean Scheme began in 1880, and was finished eight years later, at a cost of two million, seventy six thousand, three hundred and thirteen pounds. The man responsible for the design and implementation of the works was Edward Orpen Moriarty, M.A., M. Inst. C.E., Engineer-in-Chief for Harbours and Rivers.  In 1881 necessary lands belonging to the family of William Lawson were resumed to build the Prospect Reservoir, which when completed had a storage capacity of 10,812 million gallons.  The dam is an earth and rockfill bank with a puddled clay core. Work to repair slumps in the upstream face were carried out in 1889 and 1890, with other remedial work being done in 1899-1902 and in the 1970s. The walls of the dam were compacted with a volcanic roller now known as ‘Pincott’s Roller’, which is still at the site. It was used to build a dam for a Mr Pincott at Ballarat in1867 and brought to Prospect by two of his sons, George and Thomas. They used a wagon and team of ten horses to bring it to Prospect, were a team of bullocks pulled it up and down the embankment. The Reservoir has an Outlet Tower that is connected to the Valve House by an interconnecting tunnel. The Outlet Tower has three levels of valves that draw water from the Reservoir and the Valve House has valves and meters that control and measure the flow of water. The valves were supplied by Glenfield of Kilmarnock, Scotland and were installed in 1882. The meters were added in1907. Both buildings are gothic revival style, octagonal in shape, of English bond brick construction. Their decorative detail consists of a castellated parapet, sandstone base course and quoins and hood mouldings on window and door openings. The Upper Canal is still bringing water to Prospect, either into the Reservoir or into the water filtration plant that opened in 1996. Approximately 80% of Sydney’s water comes by a pipeline from Warragamba Dam to the filtration plant and approximately 20% comes from the Upper Canal or from the Prospect Reservoir. The Lower Canal closed in 1996, being replaced by an underground pipeline that now takes the water to Pipe Head at Guildford. The water in Prospect Reservoir is kept ready for emergency use by strict quality control monitoring.

VALVE HOUSES
The Upper and Lower Valve Houses were built in 1887 of rosy bricks with stone trim and whiter painted crenellated parapets. They are an excellent example of Colonial Architecture. Under the Upper  Valve House are 3 levels of Vales that were used for drawing off water from the Reservoir.
The downstream house contains valves and meters that controlled and      measured the flow of water. Glenfield of Kilmarnock supplied the valves, Scotland, and installed in 1882. The meters were added in 1907.  8        
kilometres of Water Supply Canal was completed the Public Works   Department in 1888 as the 3rd component of the Prospect Reservoir Works, thereby completing the Upper Nepean Scheme. Laid on a grade of 1 in 10,000, the Canal was a good example of 19th century hydraulic engineering. It included spillways, stormwater plumes and the Boothtown Aqueduct and conveyed Sydney’s water to Pipehead at Guildford.
PROSPECT RESERVOIR is no longer used as major source for Sydney’s water supply. Since the opening of the Prospect Water Filtration Plant in November 1996, most of Sydney’s water supply now comes directly from Warragamba Dam, through the filtration plant below rhe Reservoir wall and down to Guildford through the underground pipeline.
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