Loch Lomond And Trossachs National Park Planning Authority
J R Sutherland, 1910-15, based on designs by James M Gale prior to 1902. 350 yard long dam with crenellated parapet and curved buttresses. Concrete construction faced with coursed, bull-faced red Annan sandstone. Off-centre 9-bay spillway towards N end falling into exit channel basin with curved sides. Buttresses flanking spillway and at regular intervals with shallow machicolated detailing to string course. Crenellated parapet to reservoir side of dam-top walkway; walkway carried over spillway on series of masonry piers; tubular cast-iron railings to land side and over spillway. Crenellated curved wing wall at N end bearing large cast-bronze commemorative plaque.
VALVE TOWERS: 2 octagonal-plan valve houses with deeply crenellated tops and mutulled eaves courses house cast-iron regulating mechanism for compensation supply which flows through dam. Masonry-clad walls to exit channels.
BRIDGE: single-span, segmental-arched bridge with pyramidal-capped piers at each end and standard GCWW railings to parapet. Bull-faced coursed red Annan sandstone; prominent voussoirs. Situated a short distance down stream from the exit channels.
Statement of Special Interest
A well-detailed dam which has a picturesque and prominent position in the landscape and is a relatively early example of concrete construction in Scotland. It was constructed as part of the Glasgow Corporation Water Supply system. Due to its remote location, the materials for the dam were taken up Loch Lomond by barge and then carried to the site by a specially-built cableway that was powered by a hydro-electric plant at Inversnaid.
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. 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.
The continued expansion of the scheme during the late 19th century meant that a larger supply of water was required to keep Loch Katrine topped-up. Loch Arklet was an obvious source of supply and James Gale, who had been Water Engineer to the City of Glasgow since the opening of the scheme in 1859, drew up plans to increase the capacity of the loch and create a connection to Loch Katrine. An Act of 1902 allowed the work to take place and it was carried out by Gale's successor, J R Sutherland from about 1910 onwards. The other structures connected with this scheme, the Loch Arklet intake and outlet to Loch Katrine are listed separately.
Category changed from B to A following the thematic review of Loch Katrine water supply system in 2008.