Castleton & Cave Dale

Cave Dale was initially formed by glacial meltwater carving a deep narrow valley in the local soluble limestone. The river then found a route underground leaving a dry valley with caverns underneath. Later on the caverns below Cave Dale collapsed making the valley even deeper and gorge-like at the northern end. The Castleton entrance to Cave Dale had a narrow natural arch as recently as 200 years ago

Castleton is situated between the gritstone plateau of the Dark Peak (Northern Peak District) to the north and the gentler limestone scenery of the White Peak to the south. It lies at the western end of the Hope Valley and consequently is surrounded on three sides by hills. Most prominent is the ridge to the north. This is called Great Ridge; it runs east from Mam Tor to Back Tor and Lose Hill, via the pass (hause) of Hollins Cross, where paths from many directions converge and cross over to Edale. 

Views towards Mam Tor show the shale landslips.

Derwent Reservoir (Derbyshire) & Ladybower Reservoir

The filling of Derwent reservoir began in November 1914, and overflowed for the first time in January 1916, with the water almost immediately passing into supply. The dam can support a total of 9.64 million cubic metres of water. On the day I visited (Monday) a sign stated it is currently at 76% capacity.

Only two years after the dam's completion in 1916, it was decided that the flow from the reservoir was insufficient to support the surrounding population. As a result, between 1920 and 1931 the rivers Alport and Ashop were also diverted from the Ashop valley into the reservoir using tunnels and a Venturi flume.

The diversion helped hold back water during the construction of the Ladybower Reservoir to the south, which was constructed between 1935 and 1945.

During the Second World War, Derwent reservoir was used by pilots of the 617 Squadron for practising the low-level flights needed for Operation Chastise (commonly known as the "Dam Busters" raids), due to its similarity to the German dams.