The reservoir is located at Dunford Bridge in Barnsley 25 miles (40 km) northwest of Sheffield,[3] and is just inside the Peak District National Park on the Pennine watershed.

Dunford Bridge Dam was built in the 1850s[4] and was used to supply water not only for the River Don, but also to towns in the Spen Valley.

An iron and brick conduit was used to convey the water the 18 miles (29 km) to a processing works at Heckmondwike.

[9][10] Plans for a larger reservoir at Dunford Bridge were submitted in the early 1970s[11] as it was deemed necessary to store more water in fear of shortages in places such as Halifax and Brighouse.

Winscar was also the site of former quarry workings and the Scar suffix is typical of describing rough layers of rock projecting through the surface.

This had an adverse effect on the spawning fish grounds in the upper catchment, which necessitated the release of water in flushes to disperse the silted riverbed.

[22] The centre of the dam head is compacted rock and layered over with asphaltic concrete that covers over 270,000 square feet (25,000 m2).

Many smaller leaks had developed between 1975 and 2001, some relatively small, and initially, many of these were due to the settlement of rocks being at a different rate of stabilisation to the culverts and other grouted areas.

[37] Emergency services also use Winscar Reservoir to practise for water rescues and possible major events with mass casualties.