Arnfield Reservoir is a man-made

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

Longdendale Longdendale is a valley in the Peak District of England, north of Glossop and southwest of Holmfirth. The name means "long wooded valley" and the valley is mostly in the counties of Derbyshire and Greater Manchester. Geography The eastern part ...

in north

Derbyshire Derbyshire ( ) is a ceremonial county in the East Midlands, England. It includes much of the Peak District National Park, the southern end of the Pennine range of hills and part of the National Forest. It borders Greater Manchester to the nor ...

. It was constructed in 1854 as part of the Longdendale chain to supply water from the

River Etherow The River Etherow is a river in northern England, and a tributary of the River Goyt. Although now passing through South Yorkshire, Derbyshire and Greater Manchester, it historically formed the ancient county boundary between Cheshire and Derby ...

to the urban areas of

Greater Manchester Greater Manchester is a metropolitan county and combined authority, combined authority area in North West England, with a population of 2.8 million; comprising ten metropolitan boroughs: City of Manchester, Manchester, City of Salford, Salford ...

.The Peak District National Park - Fact Zone 21. Longdendale in the National Park
Unlike the other reservoirs in the chain, Arnfield and

Hollingworth Reservoir Hollingworth Reservoir is a former reservoir near Hollingworth, Tameside, Greater Manchester. The reservoir straddles the Greater Manchester–Derbyshire border. It was constructed in 1854 as part of the Longdendale Chain, but was abandoned in 1 ...

are not in the Etherow valley but lie in the valley of tributary brooks to the north and above (Arnfield lies around 1 mile from Bottoms Reservoir in the

Longdendale Chain The Longdendale Chain is a sequence of six reservoirs on the River Etherow in the Longdendale Valley, in northern Derbyshire. They were constructed between 1848 and 1884 to a design by John Frederick Bateman to supply the growing population of M ...

). From Arnfield the water is extracted to pass through the Mottram Tunnel to Godley. The Manchester Corporation Waterworks Act 1847 gave permission for the construction of the Woodhead, Arnfield and

s and an aqueduct to convey waters to a service reservoir at Godley. The Manchester Corporation Waterworks Act 1848 allowed the construction of Torside and

Rhodeswood Reservoir Rhodeswood Reservoir is a man-made lake in Longdendale in north Derbyshire. It was constructed by John Frederick Bateman between 1849 and June 1855 as part of the Longdendale chain to supply water from the River Etherow to the urban areas of Great ...

, and an aqueduct to convey the water to the Arnfield reservoir. The earthen embankment is 17m high and the five sections total 953 m in length. It was constructed of local clay; a masonry overflow weir protects the reservoir from overtopping. Beneath it lay the trapezoidal Longdendale aqueduct that followed the contour to take water from the reservoirs to the Godley reservoir. Until the 1960s, water was treated by passing it through straining frames at Godley. In the 1960s, a more sophisticated system of treatment was employed. Treatment plants were built at Arnfield and Godley. At Arnfield, lime, ferric sulphate and

polyelectrolyte Polyelectrolytes are polymers whose repeating units bear an electrolyte group. Ion#Anions and cations, Polycations and polyanions are polyelectrolytes. These groups dissociation (chemistry), dissociate in aqueous solutions (water), making the pol ...

are added to the water in mixing chambers. This

flocculating agent Flocculation, in the field of chemistry, is a process by which colloidal particles come out of suspension to sediment under the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. The action differs from p ...

binds together the impurities, which sink and are removed in sedimentation tanks. At Godley lime is added to remove

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

, and the water is filtered and chlorinated and fed into the distribution network. In the 1960s, part of the Longdendale aqueduct was replaced with 1200mm diameter pipes. In 1990 the Hollingworth Reservoir (now part of Swallows Wood nature reserve) was decommissioned and levelled and waters from the Ogden Brook fed into Arnfield. In 2004, two sections of the embankment were strengthened.

References

{{Authority control Reservoirs of the Peak District Reservoirs in Derbyshire

See also

References