There are a large number of reservoirs in Wales reflecting the need for the supply of water for both industry and for consumption, both within the country itself and in neighbouring England. A number also provide hydroelectricity and many old reservoirs also provided motive power for industries, especially for the processing of minerals such as metal ores and slate.
Wales has a relatively high rainfall and significant areas of mountainous topography which are sparsely populated which ensures that water is a plentiful natural resource. Much of the south and east of England has significantly lower rainfall [1] and a high population density which puts significant strain on the water supply infrastructure there. Collecting water in deep valleys with high river flows is far more efficient that trying to collect sparse rainfall in a generally flat landscape. Because of this engineers have viewed Wales as a potential supply of water. The rapidly growing populations of the industrial centres of Britain in the industrial revolution made the need for high volume supplies of clean water even more important and Wales was seen as the ideal source. Such engineering and economic views paid scant regard to the social, cultural and linguistic impacts that the constructions of large reservoirs in Wales would create.
Some reservoirs have been formed by the raising of dams on water courses, others are natural water bodies, the levels of which have been raised to various degrees both for direct supply of water or else for regulation of supply with water being extracted from the river some way downstream. Many reservoirs which were constructed for one purpose e.g. industry, may now serve different or additional purposes e.g amenity or, as in many cases, have been abandoned entirely. Reservoirs range in size with many under 1 acre in area serving local needs, up to Llyn Trawsfynydd which extends to 1,128 acres (456 ha). Bala Lake (Llyn Tegid) is a natural lake which at 1,192 acres (482 ha), [2] slightly exceeds Llyn Trawsfynydd in size, but whose height has been slightly raised.
Within Snowdonia, numerous existing natural lakes were co-opted to provide local water supplies during the late 19th and early 20th centuries. Within the Carneddau, Llyn Dulyn and Llyn Melynllyn were dammed in 1881 and 1887 respectively, to provide water to Llandudno. [3] Llyn Anafon was dammed in 1931 to allow water supply for Abergwyngregyn, Llanfairfechan and the surrounding areas. [4]
Cardiff Corporation Waterworks opened both Llanishen Reservoir and Lisvane Reservoir in 1886. It later commissioned the construction of three reservoirs in Cwm Taf to supply water to the capital. Beacons Reservoir was the first to take shape, between 1893–97, Cantref Reservoir was built between 1886–92 and the damming of the largest of the three, Llwyn-on Reservoir began in 1911 with the supply of water starting in the mid 1920s. [5]
The construction of Cray Reservoir was completed in 1907 and supplied Swansea with water. [6] Llandegfedd Reservoir was opened by the Newport Corporation in May 1965, covering 434 acres (1.76 square kms). It was originally built to supply water to Spencer Steelworks in Llanwern. [7]
Grwyne Fawr Reservoir, the only reservoir within the Black Mountains massif was completed by Abertillery and District Water Board in 1928, serving to supply water to various towns in the traditional county of Monmouthshire. [8] A holding reservoir in Cwmtillery was constructed as a part of the scheme. Blaenycwm Reservoir to the northwest of Brynmawr, was originally constructed as a water supply for Nantyglo Ironworks but enlarged for public supply during the 20th century. [9]
Llyn Brianne was constructed in the late 1960s to provide additional water supply to South Wales via the Felindre water treatment works. The original intention was to supplement supplies of water to Swansea, Neath and Port Talbot. [10]
This is a list of the 20 largest reservoirs in Wales defined by Natural Resources Wales. [13]
Dŵr Cymru is the water and sewerage company that supplies most of Wales and also supplies some bordering areas of England. Dŵr Cymru supplies over three million people. Since 2001, Dŵr Cymru has been owned by Glas Cymru, which is a one purpose company that manages and finances Dŵr Cymru as a "company limited by guarantee". It does not have any shareholders, and financial surpluses are reinvested into the company. [14]
The areas of Wales previously served by Severn Trent and Dee Valley in north east Wales were merged after Dee Valley Water was bought by Severn Trent in 2017 for £84 million. Hafren Dyfrdwy (owned by Severn Trent) replaced these areas in 2018 and is aligned with the national border, serving 115,000 people in Wales. [14]
In 1891, the village of Llanwddyn was flooded to supply water to Liverpool by damming of the River Vyrnwy. The reservoir became the largest man made reservoir in Europe. [15]
In 1964, residents of the small community of Aberbiga, composed of six farms, including Gronwen, Eblid, Ystradynod, Pen y Rhynau and Bwlch y Gle were evicted from their homes to create the Clywedog reservoir to supply the English midlands. Among those evicted were the parents of harpist Elinor Bennett and family of the tenor Aled Wyn Davies. There were protests against the flooding at the time. [16] [17]
In the early 1960s, 70 people were forced to leave their homes in Capel Celyn before the whole valley was flooded, and the Llyn Celyn reservoir built in order to supply water to Liverpool, England, 60 miles (95 km) away. Birmingham Corporation had one hundred occupants moved out of their homes in the Elan Valley, Powys, in order to build the reservoirs. [18] [19]
In total, up to 243 billion litres of water can be supplied from Wales to England annually. Water from Elan Valley is supplied to Birmingham, whilst water from Lake Vyrnwy is supplied to Cheshire and Liverpool. Welsh Water is licensed to give 133 billion litres annually from Elan Valley reservoirs to Severn Trent customers. United Utilities is able to take up to 252 million litres daily from Lake Vyrnwy in Powys (owned by Severn Trent) and 50 million litres daily from the River Dee. [20]
In 2022, Professor Roger Falconer said that England should "pay for the water", with the revenue being invested back into local communities in Wales. He added, "We would supply directly under drought conditions to the south east of England and I would see this as the oil of Wales for the future in terms of revenue." [21]
Former lecturer at Swansea University, John Ball has suggested that Welsh water is supplied to England is worth around £2bn annually. It has also been estimated that a low extraction fee of 0.1p per litre could generate £400 million for Wales. [22]
In 2022, John Armitt said that English water companies did not want to build new reservoirs which can be unpopular with communities. He added that Severn Trent (Hafren Dyfrdwy) and Thames Water were discussing water supply from Wales to southern England, including water from Lake Vyrnwy supplied via pipes or canal to the Thames basin. [23]
In February 2023, Powys council said it had written to the Welsh Government and UK government about permission to raise tax on water supplies to England. Jane Dodds, leader of the Welsh Liberal Democrats, stated that she was "totally behind" the council's proposal plans, adding that they are a "step in the right direction". [24]
In March 2023, United Utilities, Severn Trent Water and Thames Water were reportedly planning new pipeline for supply of up to 155million litres of water per day from Lake Vyrnwy in Powys to south east England. [22]
The Government of Wales Act 2006 (GoWA 2006) devolved multiple Water industry powers to the then Welsh Assembly. These powers included water supply, management of water resources including reservoirs, water quality, consumer representation, management of flood risk and coastal protection. [25]
The GoWA 2006 was changed by the Wales Act 2017 which includes devolution of water and sewerage powers as recommended by the Silk Commission. [25]
The secretary of state for Wales' intervention powers over cross-border water matters were repealed and replaced by the water protocol in 2018. [25]
The management of reservoir water quality and water resources are the responsibility of Natural Resources Wales in so far as they relate to the relevant abstraction licences and the agreed drawn down arrangements. Issues relating to the water industry in general are devolved to the Senedd. This is however subject to the reservations in Schedule 7A to the Government of Wales Act 2006 (GoWA 2006). [26]
Natural Resources Wales is responsible for managing water resources in Wales and is the regulatory body for this purpose. [27] On 1 April 2013, Natural Resources Wales took over the responsibilities of the Countryside Council for Wales, Environment Agency Wales and the Forestry Commission Wales. [28] [29] The Welsh government has decided not to pursue deregulation of the water industry, except for large industrial users that consume over 50 million litres of water annually. [30]
River regulation reservoirs may play a role in winter flood mitigation. Operational rules may prescribe a maximum water height at the end of Autumn to ensure that the reservoir can absorb any extreme winter rainfall events in the uplands thus mitigating high flows downstream, the Clywedog Reservoir performs this function on the River Severn. River regulation reservoirs are marginally cheaper to construct since there is no requirement for a take-off tower or associated large volume pipe-work or aqueducts piercing the dam wall. However a number of such reservoirs have installed hydro-electric generating sets to extract power from the released water. Examples of river regulation reservoirs include Llyn Brianne on the River Towy and Llyn Celyn and Llyn Brenig on the River Dee. [ citation needed ]
Proposals in the past have also included complex inter-river transfer schemes with, in one case, the enlargement of Craig Goch reservoir, [31] the release of water into the River Severn [32] via the Afon Elan and then a pumped transfer into the headwaters of the River Thames. [33]
It was, in part, the failure of the Llyn Eigiau dam, and consequent collapse of the dam of a second reservoir (Coedty) downstream, in the then Caernarvonshire (modern Gwynedd) in 1925 with the loss of 16 lives in the village of Dolgarrog which led to the enactment of the Reservoirs (Safety Provisions) Act in 1930. Under this legislation, all reservoir owners in Wales and England were required to have them inspected by a suitably qualified civil engineer, if the capacity exceeded five million gallons (22,700 cubic metres). The Reservoirs Act of 1975 placed further duties upon both owners and local authorities in respect of the safety of those with a capacity of more than 25,000 cubic metres. The Environment Agency assumed safety responsibilities in September 2004 and Natural Resources Wales became the responsible environmental body in 2013. [34] [29]
The Rheidol hydropower plant is the largest hydropowerplant of its kind in Wales. It has generated renewable energy since 1962, using rainfall from the nearby mountains. The plant includes a combination of reservoirs, dams, pipelines, aqueducts and power stations, over 162 square kilometres producing around 85 GWh annually which can power around 12,350 homes. [35] The Ffestiniog power station opened in Gwynedd in 1963, and Dinorwig pumped hydro plant was commissioned in 1984. Ffestiniog power station produces 360 MW whilst Dinorwig produces 1.7 GW. [36]
Since 2014 Natural Resources Wales (NRW) have enabled developers and small community groups to build 15 small scale hydro schemes in Wales, which can produce 1300 kW of energy annually. NRW have also finished building the 17 kW Garwnant small scale hydro scheme in 2017. [37]
Powys is a county and preserved county in Wales. It borders Gwynedd, Denbighshire, and Wrexham to the north; the English ceremonial counties of Shropshire and Herefordshire to the east; Monmouthshire, Blaenau Gwent, Merthyr Tydfil, Caerphilly, Rhondda Cynon Taf, and Neath Port Talbot to the south; and Carmarthenshire and Ceredigion to the west. The largest settlement is Newtown, and the administrative centre is Llandrindod Wells.
The Elan Valley Reservoirs are a chain of man-made lakes created from damming the Elan and Claerwen rivers within the Elan Valley in Mid Wales. The reservoirs, which were built by the Birmingham Corporation Water Department, provide clean drinking water for Birmingham in the West Midlands of England. The five lakes are known as the Claerwen, Craig-goch, Pen-y-garreg, Garreg-ddu, and Caban-coch.
The Cambrian Mountains are a series of mountain ranges in Wales. The term Cambrian Mountains used to apply to most of the upland of Wales, and comes from the country's Latin name Cambria. Since the 1950s, its application has become increasingly localised to the geographically homogeneous Mid Wales uplands, known in Welsh as Elenydd, which extend from Plynlimon (Pumlumon) to Radnor Forest in the east and Mynydd Mallaen to the south. This barren and sparsely populated 'wilderness' has been referred to as the Desert of Wales. The area includes the sources of the River Severn and River Wye and was unsuccessfully proposed as a national park in the 1960s and 1970s. The highest point of the range is Plynlimon, at 2,467 feet (752 m).
Lake Vyrnwy is a reservoir in Powys, Wales, built in the 1880s for Liverpool Corporation Waterworks to supply Liverpool with fresh water. It flooded the head of the Vyrnwy valley and submerged the village of Llanwddyn.
The Desert of Wales, or Green Desert of Wales, is an archaic term for an area in central Wales, so called for its lack of roads and towns, and its inaccessibility. The term was coined by English travel writers in the nineteenth century and has no equivalent in the Welsh language. The area corresponds roughly to the upland area called Elenydd in Welsh.
Perry Barr Reservoir is a covered drinking water reservoir, in north Birmingham, England, operated by Severn Trent Water. Built for the then Birmingham Corporation Water Department, on the site of the former Perry Barr Farm, it is not, despite its name, in the modern Perry Barr area, but nearby Kingstanding, at grid reference SP083951.
Llyn Celyn is a reservoir constructed between 1960 and 1965 including the highly controversial Tryweryn flooding in the valley of the River Tryweryn in Gwynedd, Wales. This included the forcible removal of the Capel Celyn village residents despite protest and opposition of Welsh MPs.
Llyn Brenig is a reservoir located on Denbigh Moors in North Wales. The artificial lake, which was constructed between 1973 and 1976, was created by building an embankment dam across the Afon Brenig valley. It lies at 1,200 ft (370 m) above sea level on the border between the counties of Conwy and Denbighshire. It is used to manage the flow in the River Dee as part of the River Dee regulation system.
Dŵr Cymru Welsh Water is a not-for-profit company which supplies drinking water and wastewater services to most of Wales and parts of western England that border Wales. In total, it serves around 1.4 million households and businesses and around three million people - and supplies nearly 830 million litres of drinking water per day.
The Clywedog Reservoir is a reservoir near Llanidloes, Wales on the head-waters of the River Severn. The construction of the reservoir was enabled by an Act of Parliament which asserted that "At certain times the flow of water in the river is inadequate ... unless that flow were regulated so as to ensure that at those times water in addition to the natural flow will flow down the river."
Llyn Brianne is a man-made lake or reservoir in the headwaters of the River Towy in Wales.
Llanwddyn is a village and community in Montgomeryshire, Powys, Wales. The community is centred on the Lake Vyrnwy reservoir. The original Llanwddyn village, about 2 miles (3.2 km) northwest, was submerged when the reservoir was created in the 1880s.
Severn Trent Water Authority was one of ten regional water authorities established in 1974. Its area of operation was the catchments of the River Trent and River Severn. It assumed the powers and responsibilities of existing water supply authorities in those catchment areas, the Severn River Authority, the Trent River Authority and the sewage and sewage disposal responsibilities of the councils within its area.
Public water supply and sanitation in England and Wales has been characterised by universal access and generally good service quality. In both England and Wales, water companies became privatised in 1989, although Dwr Cymru operates as a not-for-profit organisation. Whilst independent assessments place the cost of water provision in Wales and England as higher than most major countries in the EU between 1989 and 2005, the government body responsible for water regulation, together with the water companies, have claimed improvements in service quality during that period.
The Grand Contour Canal in England and Wales was intended to enhance and upgrade the British canal system, but was never built. This canal was proposed in 1943, and again ten years later, by J F Pownall. Pownall observed that there was a natural 'contour' down the spine of England, around the 300 ft level that connected several of the most populated areas. He put forward the idea that this contour could be used to define the course of a large European sized canal which contained no locks except at its entry and exit points. It would also serve as a water grid capable of distributing domestic water supply around England as need arises.
The Afon Clywedog is an upland headwater tributary of the River Severn in Powys, Wales. It is approximately 29 km long and has its source on the flanks of Plynlimon and has its confluence with the Severn in Llanidloes. The annual rainfall over the catchment is between 1737 mm and 1836 mm.
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