All of these reservoirs were built in the late 19th century for the Dewsbury and Heckmondwike Waterworks Board. Lower Windleden was the first to be completed in 1872, with Upper Windleden following in 1890. Winscar, Snailsden and Harden were all completed in 1899, although Winscar was called Dunford Bridge at the time. A new dam was built at Winscar between 1972 and 1975, and replaced the earlier earth dam. To fit it in, without destroying the village of Dunford Bridge, the dam is built of rock fill, which allows the faces to be much steeper than those of an earth dam, and the inner face is covered with two layers of asphaltic concrete, the first such use of this material on a dam in Britain. The dam is high and contains around of rock fill. Another innovation in its construction was the use of a hydraulic jump pool at the foot of the overflow chute, which dissipates the energy of the cascading water. The reservoir supplies drinking water to the Calder Valley, some to the north, and is also the base for Pennine Sailing Club, who offer basic training in sailing skills, on courses certified by the Royal Yachting Association.
All of these reservoirs were built in the late 19th century for the Dewsbury and Heckmondwike Waterworks Board. Lower Windleden was the first to be completed in 1872, with Upper Windleden following in 1890. Winscar, Snailsden and Harden were all completed in 1899, although Winscar was called Dunford Bridge at the time. A new dam was built at Winscar between 1972 and 1975, and replaced the earlier earth dam. To fit it in, without destroying the village of Dunford Bridge, the dam is built of rock fill, which allows the faces to be much steeper than those of an earth dam, and the inner face is covered with two layers of asphaltic concrete, the first such use of this material on a dam in Britain. The dam is high and contains around of rock fill. Another innovation in its construction was the use of a hydraulic jump pool at the foot of the overflow chute, which dissipates the energy of the cascading water. The reservoir supplies drinking water to the Calder Valley, some to the north, and is also the base for Pennine Sailing Club, who offer basic training in sailing skills, on courses certified by the Royal Yachting Association.