The River Nidd flows for approximately 2 miles (3 km) from the flanks of Great Whernside before joining the reservoir.

[5] The reservoir was built to supply water to the Bradford area of West Yorkshire.

Haden Carr reservoir was first built in the 1890s, just below Angram, and the works included the Nidd Aqueduct, by which water was transferred from Haden Carr to Chellow Heights via the Nidd Aqueduct using gravity only and no pumping.

[6] A small village was constructed at Angram site to house workers.

Once Scar House Reservoir was constructed, these become obsolete, but control machinery can still be seen on the Nidd and Stone beck inlets.