The Derwent Dams

At the northern end of Derbyshire the rain that falls on the Dark Peak of the Peak District gathers into the River Derwent, a tributary of the Trent, which cuts a deep valley through the millstone grit plateau.

The valley here is dammed by the Howden and Derwent Dams, and then, after conflux of the Derwent with the Ashop, by Ladybower Dam, to form one of Britain's major water supply systems and quench the thirst of the industrial towns of South Yorkshire and the East Midlands.

The solid stone neo-Gothic Howden and Derwent dams were constructed first, starting in 1901, with a narrow gauge railway constructed to carry rock up the valley from their quarry to Birchinlee, the temporary "Tin Town" of the builders. The upper of the two, Howden, was completed a hundred years ago, in July 1912, and Derwent followed at the end of the following year.

It immediately became clear that the dams weren't catching enough to support the growing populations and industries of the areas, and so a weir-culvert-tunnel system was constructed to divert the Ashop from the neighbouring valley into Derwent Reservoir. But even after with this source added in 1920, the problem was not really solved. In 1935 work began on Ladybower Reservoir, capturing further tributaries and extending the catchment area from 21 to 26 square kilometres, and adding 6.3 billion gallons of storage capacity to the 2.1 billion of Derwent and 1.9 billion of Howden.

These photos were all taken in May last year. I'll have to go back for more one day, though: after prolonged rain, the dam faces become huge spillways.

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