Pricing Change
New pricing for orders of material from this site will come into place shortly. Charges for supply of digital images, digitisation on demand, prints and licensing will be altered.
Glencorse Reservoir, Dam
Dam (19th Century)
Site Name Glencorse Reservoir, Dam
Classification Dam (19th Century)
Alternative Name(s) Logan Burn; Glencorse Reservoir, Embankment; Glencorse Reservoir, Bank
Canmore ID 276989
Site Number NT26SW 63.02
NGR NT 22143 63532
Datum OSGB36 - NGR
Permalink http://canmore.org.uk/site/276989
- Council Midlothian
- Parish Glencorse
- Former Region Lothian
- Former District Midlothian
- Former County Midlothian
NT26SW 63.02 22143 63532
Sluice Tower [NAT] (at NT 22108 63551)
Overflow [NAT] (at NT 22205 63576)
OS 1:10,000 map, 1976.
For adjacent Glen Cottage, see NT26SW 63.03.
Not to be confused with the minor dam carrying the track along the N side of the reservoir across a burn, for which see NT26SW 63.04.
The earthern dam ('bank') measures up to 77ft (23.5m) in height and 86,335 cu yds (66,005 cu m) in volume. Situated at a point where the stream channel was narrowed by a projecting rocky spur, its construction gave considerable difficulties. In excavating the foundation, it was discovered that the gravel bed was no less than 53ft (16.2m) deep; when this was removed to make the required clay-puddle dyke, the hill on the S side (comprising loose and friable felspathic trap) collapsed.
J Colston 1890.
Construction (1820 - 1824)
Compensation Reservoir forming part of water supply system to the City of Edinburgh. Dam designed by James Jardine, with Thomas Telford consulting engneer for the water company and Rennie consulting engineer for the mill owners.
Project (2007)
This project was undertaken to input site information listed in 'Civil engineering heritage: Scotland - Lowlands and Borders' by R Paxton and J Shipway, 2007.
Publication Account (2007)
Glencorse Dam retains the 50-acre Glencorse Reservoir which forms part of the water supply system to Edinburgh. It is located in the Pentland Hills about six miles south-west of the city and was built between 1820–24 to provide compensation water to mill owners for the water taken from Crawley Spring and Glencorse Burn to supply the city. The project was designed by Jardine, the Water Company’s engineer, with Telford acting as consulting engineer for the Company’s interest and Rennie for the mill owners.The earth dam, when built one of the tallest in Britain, is 330 ft long, 450 ft thick at the base, and about 110 ft high measured from rock level in the bottom of the cut-off trench some 50 ft below the bed of the burn. The illustration is based on Jardine’s 1819 specification before work started. There is an oval-section ashlar masonry tunnel carried through the embankment with cast-iron valve-work under a shaft to the top of the dam. Reaching an impervious bottom for the clay puddle cut-off wall proved a great problem which nearly resulted in abandonment of the dam; 10 000 cu yards of puddle clay being required to effect a seal. Crawley Cistern, a distinctive masonry building 60 ft long with a stone-slab roof surmounting a semicircular vault springing from 3 ft above floor level containing the 45ft by 15 ft open-topped masonry cistern, was designed by W. H. Playfair under Jardine’s direction. The tank is at the head of a nine-mile cast-iron aqueduct, with a maximum diameter of 20 inches, passing via Liberton and under Castle Hill to Hanover Street in the New Town on a plinth in a 6 ft by 5 ft wide tunnel.
The pipes were supplied by the Butterley Company and each was proved by subjecting it to a pressure equal to that of a column of water from 300 to 800 ft high. The whole works cost £145 000 and were dubbed by The Scotsman in 1825, ‘the most extensive, perfect and complete ever executed in modern times’.
R Paxton and S Shipway 2007
Reproduced from 'Civil Engineering heritage: Scotland - Lowlands and Borders' with kind permission of Thomas Telford Publishers.
