Thirlmere Aqueduct

The Thirlmere Aqueduct is part of a water supply system built by the Manchester Corporation Water Works between 1890 and 1925.

The aqueduct was built to carry approximately convert|55000000|impgal|m3 per day of water from Thirlmere Reservoir to Manchester. The construction of the reservoir and aqueduct was authorised by the Manchester Waterworks Act of Parliament. The first phase was completed in 1897 and, for the pipeline sections, subsequent phases were completed in 1925. The first water to arrive in Manchester from the Lake District was marked with an official ceremony on October 13 1894.

History

In 1874 John Frederick Bateman advised Manchester Corporation that the increasing demand for water, then averaging convert|18000000|impgal|m3 per day, would soon exhaust the available supply from Longdendale. His first recommendation was to source water from Ullswater, but it was eventually decided to seek powers to acquire Thirlmere and build a dam there. In the face of local opposition [cite web |title=Essays on Science and Society |work=Fighting for Thirlmere—The Roots of Environmentalism |url=http://www.sciencemag.org/cgi/content/full/300/5625/1510 |accessdate=2007-10-26] the project received Royal Assent in 1879. Under this act Manchester was granted priority of right to convert|25|impgal|L per person per day. A pumping station was built at Heaton Park Reservoir in 1954–1955 incorporating a large relief by Mitzi Cunliffe signed and dated 1955. The building materials and the reliefs are all symbolic of the achievement in bringing water from the Lake District to Manchester. The building was given grade II listing in 1988. [http://www.bury.gov.uk/VisitorGuidesAndMaps/Prestwich/Prestwich_visit.htm Retrieved 2008-01-04]

Thirlmere Dam

The dam at Thirlmere rises convert|64|ft|m|0 above the old stream bed, and the reservoir when full has a surface area of convert|814|acre|km2, and a holding capacity of convert|8235000000|impgal|m3 above the level to which water may be drawn (540 O.D.) The total dry weather yield of Thirlmere reservoir is reckoned at about convert|40500000|impgal|m3 per day, out of which compensation water in respect of the area now draining into the Lake convert|10120|acre|km2), amounting to convert|4658000|impgal|m3 per day average), is sent down the St. John's Beck. Manchester Corporation has acquired the drainage area of convert|10800|acre|km2 (in addition to other lands).

Aqueduct technical data

The aqueduct is almost convert|96|mi|km|0 long from Thirlmere reservoir to Heaton Park reservoir, Prestwich. [cite web | title= Thirlmere Aqueduct Construction Facts | work= The Hodder and Thirlmere Aqueduct Access Gates | url= http://www.aquila-management.co.uk/gates/thirlmere/facts.asp | fdormat= HTTP | accessdate= 2007-08-24] Its most common form of construction is cut-and-cover, which consists of a of "D" section concrete covered channel, approximately convert|7.1|ft|m|1 wide and between convert|7.1|ft|m|1 and convert|7.9|ft|m|1 high. There are convert|37|mi|km|1 [cite web | title= Aqueduct | work= Encyclopaedia Britannica 1911 | url= http://www.1911encyclopedia.org/Aqueduct | accessdate= 2007-12-27] of cut and cover, made up of 12-inch (30 cm) thick concrete horseshoe shaped sections. Typically, the conduit has convert|3|ft|m|0 of cover and traverses the contours of hillsides.

It is the longest gravity-fed aqueduct in the country, with no pumps along its route. The water flows at a speed of convert|4|mph|km/h|0 and takes just over a day to reach the city. The level of the aqueduct drops by approximately 20 inches per mile (30 cm/km) of its length.

Construction history

Sections of the route of the aqueduct have over time been modified for the construction of modern motorways. During the construction of the M6 and M61 connection a short section was diverted. [cite web |title=History of the M61 |work=M61 Motorway |url=http://www.lancashire.gov.uk/environment/historichighways/m61.asp |accessdate=2007-10-27] A short section of the aqueduct near Worsley in Greater Manchester was also re-routed in the late 1960s during the construction of the M62/M63/M602 motorway interchange. [cite web |title=The Motorway Archive |work=History of the M602 |url=http://www.lancashire.gov.uk/environment/historichighways/m602.asp |accessdate=2007-10-27]

References

External links

* [http://www.salford.gov.uk/living/planning/heritage-and-conservation/listedbuilding/listed-building-register/listed-building-register-a.htm Salford council website showing listed status and an image]
* [http://www.nwpho.org.uk/reports/bulletin/jan2001/index.htm North West Public health Observatory: Crytosporidium in the North West water supply]