Construction of Cordeaux Dam commenced in 1918. Cordeaux Dam is a curved dam with an unlined side spillway on the left abutment. Cement and metal were transported to the site from the main southern railway 21 kilometres away, via a 5 kilometre steam operated aerial ropeway built across the Nepean Gorge. The final journey was completed by a narrow gauge rail line.The dam was completed in 1926 at a cost of about $2.5 million. Cordeaux was upgraded in 1988, at a cost of $3 million, with a system of drains in the wall and foundations.
- Height: 57 metres
- Length: 405 metres
- Capacity: 93,640 megalitres
- Catchment: 91 square kilometres
- Lake: 7.8 square kilometres.
Did you know?
The restored locomotive "Kiama" (now owned by the Illawarra Light Railway Museum Society) used to run on a light railway between the Nepean Gorge near Douglas Park and the dam wall along Mount Keira Road during construction of Cordeaux Dam. It was later used to haul sand to build the Sydney Harbour Bridge.
The memorial garden in the picnic grounds and a plaque on the valve house pay tribute to Guy Chalmers Clift, 37, the Resident Engineer in charge of the dam's construction. On 10 March 1924, Clift and Constable James Flynn, 27, a local police officer, were shot while taking a suspect to Appin Police Station after a bungled attempt to steal the Cordeaux payroll. The intoxicated prisoner, William Simpson, 34, was later captured at the Royal Hotel in Appin, and was charged with the two murders. He was hanged at Long Bay Gaol in December 1924.