Chester Weir
Encyclopedia
Weir
A weir is a small overflow dam used to alter the flow characteristics of a river or stream. In most cases weirs take the form of a barrier across the river that causes water to pool behind the structure , but allows water to flow over the top...
which crosses the River Dee
River Dee, Wales
The River Dee is a long river in the United Kingdom. It travels through Wales and England and also forms part of the border between the two countries....
at Chester
Chester
Chester is a city in Cheshire, England. Lying on the River Dee, close to the border with Wales, it is home to 77,040 inhabitants, and is the largest and most populous settlement of the wider unitary authority area of Cheshire West and Chester, which had a population of 328,100 according to the...
, Cheshire
Cheshire
Cheshire is a ceremonial county in North West England. Cheshire's county town is the city of Chester, although its largest town is Warrington. Other major towns include Widnes, Congleton, Crewe, Ellesmere Port, Runcorn, Macclesfield, Winsford, Northwich, and Wilmslow...
, England, slightly upstream from the Old Dee Bridge . The weir and the associated salmon
Salmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...
leap have been designated by English Heritage
English Heritage
English Heritage . is an executive non-departmental public body of the British Government sponsored by the Department for Culture, Media and Sport...
as a Grade I listed building.
This was originally the site of a causeway
Causeway
In modern usage, a causeway is a road or railway elevated, usually across a broad body of water or wetland.- Etymology :When first used, the word appeared in a form such as “causey way” making clear its derivation from the earlier form “causey”. This word seems to have come from the same source by...
across the River Dee. The weir was built in sandstone
Sandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
in 1093 for Hugh Lupus, 1st Earl of Chester
Hugh d'Avranches, 1st Earl of Chester
Hugh d'Avranches , also known as le Gros and Lupus was the first Earl of Chester and one of the great magnates of early Norman England.-Early career:...
, for the Benedictine
Order of Saint Benedict
The Order of Saint Benedict is a Roman Catholic religious order of independent monastic communities that observe the Rule of St. Benedict. Within the order, each individual community maintains its own autonomy, while the organization as a whole exists to represent their mutual interests...
Abbey of St Werburgh (now Chester Cathedral
Chester Cathedral
Chester Cathedral is the mother church of the Church of England Diocese of Chester, and is located in the city of Chester, Cheshire, England. The cathedral, formerly St Werburgh's abbey church of a Benedictine monastery, is dedicated to Christ and the Blessed Virgin Mary...
). It was designed to provide a head of water for the medieval mills on the river. The mills were demolished during the 20th century and the weir was restored to serve the Chester City Council's hydro-electric
Hydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...
power station, which operated from 1913 to 1939 on the site of the former mills.
The weir continues to provide three essential roles in maintaining the very substantial water abstractions from the River Dee. It prevents tidal water ingress up-river for all but the highest tides; it provides the water head for an abstraction immediately behind the weir and it holds back what is a long linear lake which enables that largest abstraction to be taken at Huntington
Huntington, Cheshire
Huntington is a civil parish on the southern outskirts of Chester in the unitary authority of Cheshire West and Chester and the ceremonial county of Cheshire, England...
for the North West Water
North West Water
North West Water was a water supply company serving north west England. It was originally the North West Water Authority, one of ten regional authorities created by the Water Act 1973. In 1989 it became North West Water plc, and was privatised...
supply to the Wirral
Wirral Peninsula
Wirral or the Wirral is a peninsula in North West England. It is bounded by three bodies of water: to the west by the River Dee, forming a boundary with Wales, to the east by the River Mersey and to the north by the Irish Sea. Both terms "Wirral" and "the Wirral" are used locally , although the...
and surrounding areas.
The weir can navigated, by crossing over the top during high spring tides. On the city-side of the weir is the United Kingdom's only example of a weirgate, a low height single lock gate that can be opened to provide extra draft once the water levels on each side of the weir have equalised. This allows carefully planned passage from the non-tidal River Dee, via the short tidal estuary section, onto the Dee Branch of the Shropshire Union Canal
Shropshire Union Canal
The Shropshire Union Canal is a navigable canal in England; the Llangollen and Montgomery canals are the modern names of branches of the Shropshire Union system and lie partially in Wales....
(originally the Chester Canal) at certain times of year.
United Utilities are due to vacate the turbine building by 2013, allowing installation of a new hydro electric generating plant
Low head hydro power
Low head hydro power applications use river current or tidal flows of 20 meters or less to produce energy. These applications do not need to dam or retain water to create hydraulic head; the head is only a few metres...
.