The Lower Prospect Canal Reserve is a heritage-listed former farm and public water supply canal and now bushy corridor and nature reserve stretching through the heart of suburban Sydney, New South Wales, Australia. The lineal corridor stretches from Prospect Reservoir to Sydney Water Pipehead at Albert Street, Guildford with the majority of the reserve located in Greystanes, which is a suburb within the Cumberland Council area.
The Canal Reserve is one of the last remaining remnants of natural Cumberland Plain Woodland in the Sydney basin and contains a number of rare and endangered plant specimens. The land corridor occupied by the canal is recognised by the local government and documented for conservation and protection measures. Formerly a public water supply for western Sydney, the Lower Prospect Canal was eventually unneeded in May 1995 when Sydney Water authorized an underground pipeline for $54m.
The whole scheme relied on gravity and therefore demanded unerring accuracy during construction. The Lower Prospect Canal falls approximately over its 7.7 kilometre length. The scheme, including the Lower Prospect Canal, was designed by Edward Orpen Moriarty and built from 1880 to 1888 by the NSW Board of Water Supply and Sewerage; Kinchela and Metcalfe. It is also known as Lower Canal, Boothtown Aqueduct, Inverted Syphon, Aqueduct Valve House No 1 & 2 and Culvert, Covered Way, Smithfield Tanks and Sedimentation Channel. The property is Crown land and is administered by the Department of Industry, Skills and Regional Infrastructure Development, a department of the Government of New South Wales. It was added to the New South Wales State Heritage Register on 30 June 2015.
History In the 1860s following droughts and population expansion, the need for a larger and more reliable water source was required for Sydney. A Special Commission, in 1869, recommended the construction of the Upper Nepean Scheme. The proposal was approved in 1877 and work commenced in 1880. The canal was originally a dry-stone masonry construction in 1888. From 1902–12 it was largely reconstructed and relined to decrease outflow and increase capacity and stability. A part of the canal known as the Covered Way, located at the base of Prospect Hill near Hyland Road Greystanes, collapsed in 1904 and was reconstructed in 1905. The Covered Way is a basined component of the canal that protected the water supply from contamination that may have entered the canal due to the steepness and proximity of Prospect Hill.
By the late 1980s, the Lower Canal was incapable of keeping up with the growing need for water from Sydney's large population. At its peak capacity, following alterations, it could still carry only 100 million gallons per day. In addition to that, increasing standards of water quality and security of supply were rising up against the urban development that was encroaching on the setting of the open water Lower Canal.
The Upper Nepean Scheme saw water from the Upper Nepean, Avon, Cordeaux and Cataract Rivers channelled via tunnel, pipes and open canal to Prospect Reservoir. From Prospect Reservoir the water supply moved through an open canal known as the Lower Prospect Canal along the corridor now known as the Lower Prospect Canal Reserve. That use came to an end in May 1995, when the Lower Canal was drained and replaced by an underground pipeline from Prospect Reservoir to Pipehead, thus leaving the community with the chance to gain a spectacular parcel of land for recreational purposes. The pipeline increased the dependability, water quality and amount of water flow from Prospect to Pipehead.
The Lower Canal was made into a public reserve in 1998 which follows the course of the former canal. The reserve has survived the intense urban development that surrounds it, due to its use, for over 100 years, as part of the water supply system for Sydney. August 2003 saw the reserve opened to the community with a cycleway–walkway (Western Sydney Parklands-Canal Reserve cycleway) running its full length and connecting with other cycleways that extend across a great part of the Sydney metropolitan area.
Geography
Connected to Marrong Reserve to the west, the reserve is just over 6.6 km long, starting from Reconciliation Road, Pemulwuy, passing through the suburbs of Greystanes, Smithfield, Merrylands and Woodpark, to its endpoint at Pipehead, Guildford. The Lower Canal snakes its way on the edge of a natural ridge from the western part slowly falling to an artificial constructed embankment at the eastern end.
The elevation of the western end of the canal is approximately 60-70m above sea level, falling to 40m. Three roads with bridges transverse over the Lower Canal: Gipps Road, Cumberland Highway and Sherwood Road. Medium-density housing borders the reserve to the north and south with light industry located to the south near Smithfield. The canal is now surrounded on both sides by managed nature reserves.
Canal Road Park, located on the western outskirts of Greystanes, near Merrylands West, is on an elevated ridge, which provides panoramic views of southwestern Sydney. It also features a children's playground, BBQ area and picnic shelters.Lower Canal—Prospect. Proposed Transitway Intersection, Godden Mackay Logan, 2002
Structure The canal was an open gravity flow with a gradient of approximately per km over its length. The upper width varied between and its depth between 2.4 and 3m. About east of the start of the canal, at Prospect Reservoir, the Lower Canal was diverted underground for . This was designed so to protect the canal water from contamination by the slope of Prospect Hill through which it was cut.
The valve house at the head of the canal at Prospect Reservoir have inlet pipes, which allowed water to pass from the reservoir into the canal to start its journey to Pipehead. The inlet pipe flow was controlled by a set of valves housed within the valve house adjacent to the receiving basin. Inlet pipes in the base of the receiving basin allowed water to pass from the reservoir into the canal to start its journey to Pipehead. The inlet pipe flow was controlled by a set of valves housed within the valve house adjacent to the receiving basin. At the farthest point of the canal, prior to it entering Pipehead, there are two sedimentation chambers and a central bypass which were used to trap sediment from the water before it entered the Pipehead pumphouse. On the south side of the canal, adjacent to Percival Road, there are two in-ground tanks, the first built in 1895, that were used to supply Smithfield with water.
Today, these tanks have been unheeded and are hard to situate due to overgrowth. The upper of canal wall was left open so visitors can observe the canal's path and to stipulate a clear view between the bushland and the retained sod that is used between the concrete cycleway and the canal walls.Archival Record & SOHI, Lower Canal, Prospect to Pipehad (Part of Upper Nepean Scheme) Vol 1 History, Description & Statement of Significance, Edward Higginbotham, 2000
A detention basin (Widemere Detention Basin), which stores stormwater runoffs, exists just north of Wetherill Park between Prospect Highway and Hyland Road in Greystanes. If the rainwater is less than the basin's capacity, there will be no discharge, but if the waters exceed they will overflow into Prospect Creek. The water levels in the basin is supervised and modified to guarantee capacity for a 90th percentile 5 day rainfall event. Though the water in the detention basin is generally recycled.Widemere Operation Environment Management Plan by Boral. 21 January 2001
Modifications and dates The following modifications were made to the structure:
1895Smithfield Tanks (reservoir) constructed for water supply for Smithfield 1902–12Relining of the canal with Monier plates or concrete to increase the capacity of the Lower Canal by around 75%; walls of Smithfield Tank raised 1903Sedimentation Chambers constructed west of Pipehead 1905Rebuilding of the Covered Way in concrete following its collapse 1907Boothtown Aqueduct ceases operation. Inverted Syphon constructed alongside Boothtown Aqueduct 1911Construction of Gipps Road Bridge over Lower Canal 1995Lower Canal replaced by an underground pipeline from Prospect Reservoir to Pipehead, Lower Canal decommissioned and dewatered 2001Work commenced on the Lower Prospect Canal Reserve to create a combined pedestrian/cycleway commencing at Prospect Reservoir and terminating at Pipehead Guildford. Infilling involved protection of the canal walls; installation of drainage measures and infilling with a mix of concrete aggregate and packed soil layers. An aggregate or plain pathway was constructed. The heritage significance of the canal was a consideration in this process and the infilling is reversible 2003Lower Prospect Canal Reserve and pedestrian/cycleway officially opened. Reserve gazetted as Crown Land in 2004 with Holroyd City Council as trustees 2008A section of the infilled Lower Canal on the western boundary of the Prospect Reservoir SHR listing was removed in 2008 for the construction of Reconciliation Road. The Lower Prospect Canal Reserve now commences at Reconciliation Road
Controversy At the end of April 2008, the final section of the canal leading to the Prospect Reservoir was sectioned off and destroyed as Boral, under direction of the RTA, commenced work on extending Reconciliation Drive from the Prospect industrial zone through to Wetherill Park. Work was scheduled to be completed by mid October 2008 but was still continuing as of early 2013.
This work has proved controversial with the community as a section of the historic canal has been destroyed and a bridge originally promised to traverse the new highway and transitway will now not be built. A previous heritage listed feature of the old Widemere Quarry railway line had been preserved by building the main access road around the old bridge supports. The community is now waging a battle with the NSW State Government to have this decision reversed.
Heritage listing
The reserve was listed on the New South Wales State Heritage Register as a site of State significance on 18 November 1999 with the following citation:
The Lower Prospect Canal Reserve is of state significance for the former Lower Canal contained within the reserve and the natural heritage values of the reserve. The Lower Canal, and its associated infrastructure, is state significant as a key component of the Upper Nepean Scheme. This scheme was the outcome of the first major engineering investigation in NSW into the provision of an adequate and reliable water supply to meet the needs of a rapidly growing Sydney.
The Upper Nepean Scheme was Sydney's fourth water supply, and its first reliable, and most enduring, engineered water supply. It marked a major engineering advance from locally sourced to remotely harvested water, obtained from rivers in upland catchment areas, that was stored in dams and transported by weirs, open channels, tunnels and pipelines to its final destination. The Upper Nepean Scheme was one of the largest engineering and public infrastructure works carried out in Australia up to 1888. It was an important determinant of Sydney's growth potential. No other similar water supply canals of the form and scale of those associated with the Upper Nepean Scheme have ever been built in NSW. The scheme is a system that has lent itself to progressive development to meet Sydney's increasing water supply needs. It continues to function for the purpose for which it was designed and constructed.