Woodhead reservoir is a man-made lake near the hamlet of Woodhead in

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 by

John Frederick Bateman John Frederick La Trobe Bateman (30 May 1810 – 10 June 1889) was an English civil engineer whose work formed the basis of the modern United Kingdom water supply industry. For more than 50 years from 1835 he designed and constructed reser ...

between 1847 and June 1877 as part of 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 ...

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
/ref> It is at the top of the chain of reservoirs and was the first to be started, though, due to construction problems, it was the last to be completed.

Act of Parliament

The Manchester Corporation Waterworks Act 1847 gave permission for the construction of the Woodhead and

Arnfield reservoir Arnfield Reservoir is a man-made lake in Longdendale in north Derbyshire. It was constructed in 1854 as part of the Longdendale chain to supply water from the River Etherow to the urban areas of Greater Manchester.Mottram Tunnel. 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 from Rhodeswood to the Arnfield reservoir. These acts were important, as mill owners relied for their livings on water to power their mills and any potential reduction of supply was opposed. The acts guaranteed a flow of 121 million gallons a week.

Construction

The construction of the Woodhead Embankment was ambitious and fraught with difficulties. The embankment was to be about in height; it was sealed to the underlying impermeable rock by a central impermeable clay puddle core or curtain. This was supported on each side by selected strong earth material, and then gravel to form a slope of 1 in 1 upstream and 1 in 2 downstream. The upstream would be pitched, and faced in stone. The turnpike would pass over the crest. Drinking water would be extracted by means of a tunnel from several metres below the water level, while when full, excess water would pass over the overspill or waste weir.

The first embankment

Work started in 1848. The Heyden Viaduct, now known as the Woodhead Bridge, was completed in 1851, and turned over to the Salters Brook turnpike road that year. The Woodhead embankment was from completion. Discharge valves had been supplied by Messrs Armstrong and Co, of Newcastle upon Tyne. There was some leakage but on 10 May 1854 the Woodhead Reservoir was declared complete, with the exception of remedying the leak. To stop the leak, borings had been made, and ash injected under pressure in the hope it would act as a sealant. In 1858, it was concluded that this would not work; the Etherow valley was on multiple fissures relating to a fault that was causing movement in the soft beds of shale underlying the harder rock beneath the valley. This was the cause of the landslides at Rhodeswood, and the continual problems at Woodhead.

The second embankment

In 1862 a second embankment downstream of the first embankment was proposed. This took advantage of a continuous length of shale suitable for a seal. The space between the two embankments was infilled. The new puddle trench was sunk beneath the height of the first embankment, below the old riverbed, in the main through solid rock. It was filled with concrete as clay could not withstand a water head of 160 feet. The reservoir was filled in 1877.

Safety measures

It was stated in a statutory report, under the Reservoir Safety Act 1975, dated 12 June, that all five reservoirs could be over-topped during a Probable Maximum Flood. Woodhead as the fountainhead had the most extensive improvements, relieving the pressure on the other reservoirs. The work took place between 1989 and 1992 at a cost of £3m. The storage level of the reservoir remained the same but the embankment crest was raised by , which meant replacing the B6105 road at a higher level and on a new course. An impervious clay membrane was laid in the upstream face to provide continuity with the 1877 embankment. This was protected with concrete matting faced in stone. The length of the overflow sill was reduced and a new concrete box section installed to throttle the flow, which was directed into the Etherow Pool. A replacement diameter guard valve was installed.

References