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Llanishen Reservoir

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Llanishen Reservoir
Llanishen reservoir in a semi-drained state
Llanishen reservoir (semi-drained)
LocationLlanishen, Cardiff, Wales
Coordinates51°31′43″N 3°10′21″W / 51.52861°N 3.17250°W / 51.52861; -3.17250Coordinates: 51°31′43″N 3°10′21″W / 51.52861°N 3.17250°W / 51.52861; -3.17250
Primary inflowsRainfall
Primary outflowsDrainage
Basin countriesUnited Kingdom
First flooded1886
Surface area23.8 ha (59 acres)
Max. depthm (30 ft)
Water volume1,440,909 m3 (50,885,200 cu ft)
Surface elevation45 m (148 ft)
FrozenLast frozen during Winter 09/10

Llanishen Reservoir (Welsh: Cronfa Ddŵr Llanisien) is a Victorian reservoir in North Cardiff in Wales. The reservoir is one of the reservoirs constructed as part of the Taff Fawr scheme for supplying water to Cardiff and was completed in 1886. It forms part of the Nant Fawr Corridor from the top of Roath Park to the countryside beyond Cyncoed.

The reservoir was used for water supply until the mid-1970s when it became redundant. It was then used for leisure activities and for 'topping up' the adjacent Lisvane Reservoir until it was drained completely.[1] After buying Hyder plc, its new owner Western Power Distribution (WPD), proposed to redevelop the reservoir site, but after a series of objections from national governing bodies, the County Council, local residents and both local and national politicians this was blocked. On 30 August 2013 WPD sold both Llanishen and Lisvane reservoirs to CELSA Group.[2]

In January 2016, Welsh Water acquired both Llanishen and Lisvane reservoirs from CELSA Group on a 999-year lease, which allows Welsh Water to use both reservoirs for water supply and recreational purposes while also allowing CELSA UK to continue to take its water supply from the Lisvane reservoir.[3]


Many original features are still intact.

In 1881, a report was commissioned on water resources within a reasonable distance of Cardiff. The report concluded that the Taff Fawr scheme would fulfil the town's requirements at the least cost and it was decided to create Llanishen Reservoir.[4] Construction of the reservoir started in 1882[4] by the engineer James Simpson for the Cardiff Waterworks Company and was completed in 1886.[5]

The reservoir is retained by an earth-filled embankment with a clay core some 10 metres (33 ft) high and about 1,173 metres (3,848 ft) long. The external embankment face is grassed whilst the internal face has stone pitching over the upper part and concrete over the lower part. It has a maximum surface area of water of 23.8 hectares (59 acres) and a capacity of 1,440,909 cubic metres (50,885,200 cu ft).[6]

The reservoir is underlain by the St Maughan's Formation of the Lower Devonian age.[5] Glacial till deposits of the Devonian age form part of the northern shore of the reservoir. The reservoir may be on the northern limb of the Cowbridge anticline.

The reservoir was transferred to Welsh Water in 1973[7] when the Welsh Water Authority was formed, and it supplied water until the mid-1970s. In 1996 Welsh Water's holding company was renamed as Hyder plc and the group acquired South Wales Electricity plc.[7] After Hyder's share price collapsed in 1999 and 2000,[7] the Hyder Group was sold to WPD on terms recommended by the Hyder Board[8] after a competitive and hostile takeover battle.[9] WPD is the American-owned electricity distribution network operator for South West England and South and West Wales.

Welsh Assembly members were concerned that the takeover would mean jobs being transferred to Bristol and Cheshire, and at its effect "on consumers' interests, on the environment, and on the wider economy".[9][10]

WPD acquired the reservoir from Welsh Water in 2001 when Welsh Water was acquired by the not-for-profit organisation Glas Cymru:[11][12][13] the reservoir was sold to a WPD subsidiary, Hyder Industrial Group Ltd,[12] which was later renamed Western Power Distribution Investments Ltd.

The reservoir, which forms part of the Nant Fawr corridor,[14] has been redundant since the 1970s[15] and has only been used for leisure purposes and for 'topping up' the adjacent Lisvane Reservoir.[1]


Hygrocybe punicea is one of the many Hygrocybe species found on the reservoir banks.

The reservoir is listed as a Site of Nature Conservation Interest (SNCI) as it has pondweed and stonewort, and common toads breed there.[16] The grassland and scrub surrounding the reservoir is also an SNCI due to the grass snakes and slowworms there.[16]

The banks of the reservoir are listed as a Site of Special Scientific Interest (SSSI) due to the diversity of waxcap fungi discovered growing on them.[5][17] WPD appealed against this listing stating the Countryside Council for Wales's (CCW) decision was 'premature, arbirtrary and unfair',[18] but in January 2007 a High Court Judge upheld the SSSI designation and said it was 'an important site'.[19]

The reservoir was also listed by Cadw in July 2009 as a building of special architectural or historic interest, despite an appeal from WPD against the listing.[20]


Sailing tuition taking place on Llanishen Reservoir

Until Spring 2010, Cardiff Sailing Centre operated at the reservoir offering dinghy sailing, windsurfing, powerboating and canoeing courses. The centre, which is owned and managed by Cardiff County Council had been running at the reservoir for 30 years, though had to relocate to Cardiff Bay to continue operating due to the drain-down.[21]

The Centre has gained national recognition as both a 'grass-roots' training centre through the RYA's OnBoard scheme[22] and as a first class race training centre & club.[23][24] The Centre has also produced National & International class sailors over the years.[25]

The reservoir was also once popular with anglers (through the Cardiff Fly Fishing Club), picnickers, birdwatchers and walkers. Fishing at the reservoir stopped in 1998[26] and many of the other activities have been curtailed since 2004 due to the security fence that was constructed around the banks of the reservoir and (less securely) to the site boundary.[27]

Many people still walk between the 'inner' and 'outer' fences, due to a number of natural and man-made gaps in the outer fence and the natural hedges. Although the site is monitored, only some of the 'gaps' are resecured.

Proposed redevelopment[edit]

The reservoir, currently drained until further notice.
The inner surrounding fence, with surveillance sign.

WPD have proposed redevelopment since 2002.[28] The latest proposal is for 300 new homes, surrounding a much reduced water area, and a connected 'wetland area', as well as a new sailing club and wildlife and education centre.[29][30] This proposal was recommended by the Planning Inspector,[15] but rejected by the Environment Minister.[31] WPD requested a judicial review of the decision and the minister withdrew her defence after considering WPD's submission.[32] The Court referred the decision back to the minister and a decision is awaited.

In March 2010, work started to drain the legal limit of 3 metres (9.8 ft) of water[21] from the reservoir into the nearby Nant Fawr stream.[33] WPD say that the drain-down is required as a result of a statutory inspection carried out by WS Atkins PLC.[15] But the Environment Agency have disagreed.[34][35][36] The drainage is opposed by opponents of the redevelopment, who claim that the reservoir will take 8 years to refill if totally emptied.

The public enquiry considered the requirement for drain-down and the ecological effects in detail. On the drain-down the Planning Inspector concluded that opponents' suspicions had been "fully rebutted".[15] And after considering a lot of evidence the Inspector concluded that CCW were content for development to proceed and that "significant ecological benefits would result from the development".[15]

In May 2010, WPD applied to the Environment Agency for a discharge licence in order to completely drain the reservoir, which was granted in July 2010.[37] The issue was taken to UK Parliament by Jonathan Evans where he stated that an independent report by the Halcrow Group (advising for the Environment Agency) explained that draining the reservoir could create 'new risks to reservoir safety'.[38][39] Evans' predecessor, Julie Morgan, had previously taken the issue of saving the reservoir site to parliament,[40] and had garnered support from politicians such as Peter Hain (the Welsh Secretary) and Ed Miliband (later leader of the Labour Party), who visited the site during the May 2010 general election campaign, commenting on the site's tranquillity.[41][42]

In March 2011, WPD applied to Cardiff County Council for planning permission for a miniroundabout on Lisvane Road and listed building consent to alter the structure of the reservoir. Both of these were called in by the Welsh Government. During the appeal a number of changes to the original appeal were submitted by WPD and accepted by all parties.[43] The appeal was heard during the Summer of 2011.

On 25 April 2013, The Welsh Government refused the planning appeal from WPD which was for 324 homes.[43][44][45]

On 30 August 2013, CELSA Group bought both Llanishen and Lisvane reservoirs from their owner Western Power Distribution, to assure its Cardiff rod mill plant a consistent supply of water from Lisvane.[46]

In January 2016, Welsh Water acquired both Llanishen and Lisvane reservoirs from CELSA Group on a 999-year lease. The campaign against development of the site led by the Reservoir Action Group welcomed the move and hoped that the site could be reopened to the public in future.[3]


  1. ^ a b Waldram, Hannah (20 July 2010). "Llanishen reservoir draining permitted". The Guardian. London. Retrieved 2 September 2010.
  2. ^ "Celsa steel buys Llanishen and Lisvane reservoirs". BBC Wales. 3 September 2013. Retrieved 3 September 2013.
  3. ^ a b "Victory at last! Battle to save Llanishen Reservoir finally won after Welsh Water acquires 999-year lease". WalesOnline. 18 January 2016. Retrieved 4 April 2016.
  4. ^ a b "The Corporation Waterworks undertaking". British History Online: Cardiff Records: volume 5 (1905). pp. 457–469. Retrieved 2 September 2010.
  5. ^ a b c "SSSI Citation for Llanishen and Lisvane Reservoir Embankments" (PDF). Countryside Council for Wales. Retrieved 2 September 2010.
  6. ^ "Environment Agency – Permit to Drain Llanishen Reservoir" (PDF). Environment Agency. 19 July 2010. Retrieved 2 September 2010.
  7. ^ a b c "Hyder plc – Company Profile, Information, History etc". Reference for Business. Retrieved 2 September 2010.
  8. ^ "Hyder directors approve WPD takeover". 8 August 2000. Retrieved 2 September 2010.
  9. ^ a b "The Hyder takeover countdown". BBC. 14 August 2000. Retrieved 2 September 2010.
  10. ^ "Sue Essex concerned at uncertainty surrounding Hyder take-over". Welsh Assembly Government. 14 August 2000. Retrieved 2 September 2010.
  11. ^ "Glas Gymru Company Information". Welsh Water. Retrieved 25 April 2013.
  12. ^ a b "Dwr Cymru Company Report (Part 2)" (PDF). Dwr Cymru. 4 May 2001. p. 172.
  13. ^ "Glas acquires Welsh Water" (PDF). Glas Cymru. 11 May 2000. Retrieved 2 September 2010.
  14. ^ "Nant Fawr Corridor". Cardiff County Council. Retrieved 3 September 2010.
  15. ^ a b c d e "WAG Planning Inspectors Report" (PDF). Welsh Assembly Gofernment. p. 30, Paragraph 97. Retrieved 2 September 2010.
  16. ^ a b "WPD Planning Appeal". Welsh Assembly Government. 16 April 2009. Retrieved 2 September 2010.
  17. ^ "Fungi may halt luxury homes plan". BBC. 10 March 2005. Retrieved 2 September 2010.
  18. ^ "Judge backs rare fungi protection". BBC. 26 January 2007. Retrieved 2 September 2010.
  19. ^ "Statutory listing of Llanishen Reservoir as a building of special architectural or historic interest". Welsh Assembly Government. 23 July 2009. Retrieved 2 September 2010.
  20. ^ a b "Sailing club's frustration as Llanishen reservoir levels fall". 15 March 2002. Retrieved 31 October 2010.
  21. ^ "Cardiff school children get OnBoard". Yachts and Yachting. 25 June 2009. Retrieved 2 September 2010.
  22. ^ "Sailing Centre lands top award". South Wales Echo. 10 September 2002. Retrieved 2 September 2010.
  23. ^ "List of RYA Volvo Champion Clubs". Royal Yachting Association. Retrieved 2 September 2010.
  24. ^ "Hannah's in the frame for 2012 Games". South Wales Echo. 21 October 2009. Retrieved 2 September 2010.
  25. ^ "Fishing History of Llanishen Reservoir". Reservoir Action Group. Retrieved 2 September 2010.
  26. ^ "Gates closed at reservoir". 31 December 2004. Retrieved 2 September 2010.
  27. ^ "Action group prepares for reservoir battle". BBC. 29 November 2002. Retrieved 31 October 2010.
  28. ^ "Redevelopment Plan" (PDF). Llanishen Water. Retrieved 3 September 2010.
  29. ^ "Fight over Llanishen reservoir in Cardiff continues". BBC. 24 July 2010. Retrieved 3 September 2010.
  30. ^ "'Excellent' decision on reservoir". BBC. 20 April 2009. Retrieved 3 September 2010.
  31. ^ "Successful challenge to Welsh Ministers' planning appeal decision". Welsh Assembly Government. 7 September 2009. Retrieved 3 September 2010.
  32. ^ "Pipes in place to drain Llanishen Reservoir". 26 February 2010. Retrieved 3 September 2010.
  33. ^ "Environment Agency – Briefing Note". Environment Agency. 24 October 2010. Archived from the original on 2 February 2011. Retrieved 19 November 2010.
  34. ^ "Company told Llanishen Reservoir claims are 'erroneous'". 25 March 2010. Retrieved 3 September 2010.
  35. ^ "Call to stop draining Llanishen Reservoir". BBC. 4 March 2010. Retrieved 3 September 2010.
  36. ^ Waldram, Hannah (20 July 2010). "Llanishen reservoir draining permitted". The Guardian. London. Retrieved 3 September 2010.
  37. ^ Waldram, Hannah (7 July 2010). "Cardiff MP shows safety risks of Llanishen reservoir drain down". The Guardian. London. Retrieved 3 September 2010.
  38. ^ "Second engineer has fears on draining Llanishen Reservoir". 8 July 2010. Retrieved 3 September 2010.
  39. ^ "House of Commons Main Chamber Debates 25 February 2010". UK Parliament. Retrieved 31 October 2010.
  40. ^ "Peter Hain listens to concerns of reservoir campaigners". 5 March 2010. Retrieved 31 October 2010.
  41. ^ "An early glimpse of the leader he was destined to become". 27 September 2010. Retrieved 31 October 2010.
  42. ^ a b "WAG Inquiry Decision Letter" (PDF). Welsh Government. Retrieved 25 April 2013.
  43. ^ Owen, Cathy (25 April 2013). "Welsh Government throws out plans to build on Llanishen Reservoir". Retrieved 25 April 2013.
  44. ^ "Llanishen reservoir: Homes plan appeal rejected by Cardiff Council". BBC. 25 April 2013. Retrieved 25 April 2013.
  45. ^ "Steel Giant Celsa buys up Cardiff Reservoirs".

External links[edit]