Aurs Road, Balgray Reservoir Draw-Off Tower Mearns, Scotland

Text courtesy of Historic Environment Scotland. © Crown Copyright, reprinted under the Open Government License.

A good and early working example of a reservoir draw-off tower. Its function was to draw water out of the reservoir, which was then discharged into Ryatt Linn Falls Basin on the other side of Aurs Road and thence would enter either Ryatt Linn, Waulkmill Glen or Littleton reservoir, depending on the level of demand. Balgray reservoir was the last, and largest reservoir built for the Gorbals Gravitation Water Company (GCWC) as part of an extension to their original scheme, which was constructed 1847-8. The GCWC scheme was one of the first large-scale water supply schemes in Scotland and, although eclipsed by the slightly later scheme from Loch Katrine, is nevertheless of considerable historical and engineering interest. Balgray reservoir covers an area of 153.5 acres with a capacity of nearly 120 million cubic feet. This more than doubled the size of the original scheme, the three reservoirs of which (Waulkmill Glen, Ryatt Linn and Littleton) have a capacity of roughly 50 million cubic feet. As well as significantly increasing capacity, Balgray was designed to allow sediment in the water to settle out before the water passed through to the smaller reservoirs. The principal feature of Balgray reservoir is this crenellated draw-off tower, which encases a large cast-iron cylinder with openings at various heights controlled by sluices that feed into two 24-inch diameter pipes. A similar arrangement exists at Waulkmill Glen reservoir. The Gorbals Gravitation Water Company was originally a private firm established to supply water to the Gorbals, the inhabitants of which were keen to establish their own water supply as water provision in the area was poor, relying largely on wells. The Brockburn was identified as a good potential source, and after some opposition an Act of Parliament was passed in 1846 allowing this. The first phase of the scheme (which was always intended for expansion) comprised Waulkmill Glen, Ryatt Linn and Littleton reservoirs and associated filters, and supplied water to the Gorbals, Pollokshaws and Govan. It was built in 1847-8 by the engineer William Gale, elder brother of James M Gale who worked on the Loch Katrine scheme. The construction of the scheme was a considerable engineering achievement and the cast-iron pipes used to carry the water from the reservoirs to the filters and thence into the city were made using newly-developed vertical casting technologies. In 1853 a further Act of Parliament was passed to allow the expansion of the scheme with the construction of Balgray reservoir. This enabled it to supply Rutherglen, Nitshill, Hurlet, Barrhead, Renfrew and surrounding areas with water as well as the places mentioned above. In 1855 the company was bought out by Glasgow Corporation Waterworks, and therefore became publically-owned. Listed as part of the thematic review of the Glasgow water supply system (2008).