Talla Reservoir, Inner Shaft
Shaft (19th Century) - (20th Century)
Site Name Talla Reservoir, Inner Shaft
Classification Shaft (19th Century) - (20th Century)
Alternative Name(s) Talla Water; Talla Waterworks Scheme
Canmore ID 276338
Site Number NT12SW 17.02
NGR NT 10726 22819
Datum OSGB36 - NGR
Permalink http://canmore.org.uk/site/276338
- Council Scottish Borders, The
- Parish Tweedsmuir
- Former Region Borders
- Former District Tweeddale
- Former County Peebles-shire
NT12SW 17.02 10726 22819
Inner Shaft [NAT]
OS 1:10,000 map, 1989.
The inner shaft is accessed by a gangway, and contains the calves by means of which the water is regulated at three different levels. Each is controlled by a 24 inch (0.61m) valve worked by hydraulic power, the pressure from which is obtained from water stored in a tank 550ft (168m) above the top water level of the reservoir. The shaft is situated on the line of the discharge tunnel.
When the works were sufficiently advanced to allow water storage to begin, a brick plug 18ft (5.5m) long was installed. Two 36in (0.91m) pipes were laid at the proper level while the brickwork was being installed; the discharge through these pipes is controlled by valves. The compensation water is destroyed through the 36in pipe at the bottom of the shaft; this pipe can be used with the other 36in pipe to empty the reservoir or for scouring purposes.
The valves on these two pipes are in duplicate, one being worked by hydraulic power and the other by hand. The water passes along pipes within the tunnel into the measuring house (NT12SW 17.06), where it passes through screens before entering the aqueduct.
The inner shaft valve was closed for the first time on 20 May 1905.
W A Tait 1905.
