Loch Lomond And Trossachs National Park Planning Authority
John F Bateman 1856-59; James M Gale 1880-1. 2 adjacent aqueduct bridges carrying syphon pipes across the River Duchray.
1859 BRIDGE: 3-span bridge with central segmental-arched cast-iron span with open spandrels over river and small round-headed masonry arches to each side. Slightly battered pilastered piers flanking each masonry arches; battered masonry abutments. Squared whinstone rubble with red sandstone ashlar dressings. String course; projecting cope. Later (probably circa 1880) railings to parapet with flower motif to top section of uprights and spiked ball finials to principal uprights. Timber-boarded carriageway. Standard GCWW cast-iron gates at each end set between random rubble walls.
1880 BRIDGE: mild steel trussed girder bridge supported on tapered masonry piers with battered abutments to each end. Coursed, bull-faced red sandstone piers; roughly-coursed whinstone rubble abutments.
Statement of Special Interest
A-Group with Duchray Valley Valve House.
The finest of the 6 syphon pipe aqueduct bridges built as part of the first phase of the Glasgow Corporation Water Works system (see below for significance of the scheme as a whole) from 1856 onwards. The conduit is predominantly subterranean, but the valleys of Duchray, Endrick and Blane, which were too deep and broad for the use of normal aqueduct bridges, necessitated the use of syphon pipes to carry the water across them. The pipes are predominantly carried underground, but at a small number of points bridges were required to carry them over roads or rivers. This bridge is of particular interest largely because of the use of cast-iron in its construction (necessitated by the lack of suitable building stone in this area), but also because of its clear grouping with the nearby valve house (listed separately) and other related structures (not listed) including the keeper's cottage and retaining walls on the steep slope leading down to bridge. Because the Duchray Valley is narrower, steeper and less built-up than the other two syphon valleys, the engineering of the syphon system is much more readable here and its is easy to discern the course of the pipes.
The 1856 bridge carries two 48 inch diameter cast-iron pipes. The pipes themselves represent a considerable technical achievement, using newly-developed vertical casting technologies. The scheme was originally opened with only 1 pipe, but expanded in the 1860s and again in the 1880s, when the second bridge was built. Bateman's drawings show that he originally intended the third pipe to be carried on top of the other two, but this was evidently not felt to be practical, possibly because the 3rd pipe (42 inch diameter) was larger than Bateman had anticipated. It should be noted that the 2nd bridge is not connected with the duplication scheme of 1885, which by-passed the Duchray valley altogether.
The Glasgow Corporation Water Works system, which brings water down to Glasgow from Loch Katrine, was admired internationally as an engineering marvel when it was opened in 1860. It was one of the most ambitious civil engineering schemes to have been undertaken in Europe since Antiquity, employing the most advanced surveying and construction techniques available, including the use of machine moulding and vertical casting technologies to produce the cast-iron pipes. The scheme represents the golden age of municipal activity in Scotland and not only provided Glasgow with fresh drinking water, thereby paving the way for a significant increase in hygiene and living standards, but also a source of hydraulic power that was indispensable to the growth of Glasgow's industry as a cheap and clean means of lifting and moving heavy plant in docks, shipyards and warehouses. The civic pride in this achievement is visible in every structure connected with the scheme, from the neatly-detailed gates and railings along its route, to the massive masonry structures and iron troughs that carry the conduit and, in most cases, have withstood without failure or noticeable deterioration the daily pressure of many millions of gallons of water for well over 100 years.
Glasgow's Lord Provost, Robert Stewart (1810-66) was the driving force behind the implementation of a municipally-owned water scheme to provide clean water to Glasgow's rapidly increasing population. Loch Katrine was identified as a suitable supply and after some objections from various parties, an Act of Parliament authorising the scheme was passed in 1855. The scheme was built in two main phases following this Act and another 1885. The 1855 scheme, which was opened by Queen Victoria in 1859 and was fully operational by 1860, had been designed to allow for significant expansion as demand increased, and this work was carried in the 20 years following the opening. The 1885 Act allowed a second aqueduct to be built, which followed a slightly shorter course than the earlier scheme. The capacity of the second aqueduct was also expanded during the first half of the 20th century.
John Frederick Bateman (1810-1889) was chosen as the engineer for the scheme and construction work commenced in 1856. Bateman was to become one of the world's most eminent water engineers, and worked on a number of other water supply schemes in Britain, Europe and Asia. He was assisted by James Morrison Gale (1830-1905), who on the completion of the initial scheme in 1859 was appointed Water Engineer for the City of Glasgow, a post he held till 1902. Gale was responsible for over-seeing the incremental expansion of the first scheme during the 1860s and '70s and the building of the second aqueduct from 1885 onwards.
Previously listed as 'River Duchray Aqueduct Bridge and Aqueduct at NS 46326 / 99333'. Category changed from C(S) to A in 2008 following the thematic review of Loch Katrine water supply system.