The aqueduct comprises 54 kilometres (34 mi) of open canals, tunnels, and closed pipelines that connect the Upper Nepean Scheme with the Prospect Reservoir.

The Upper Nepean Scheme supplies water from the Cataract River at Broughtons Pass to the Crown Street reservoir, a distance of 101.79 kilometres (63.25 mi).

The Upper Canal commences by tunnel from Pheasant's Nest Weir on the Nepean River and extends through the local government areas of Wollondilly, Camden, Campbelltown, Liverpool, Fairfield, and Cumberland,[1] to terminate at the Prospect Reservoir.

This scheme was to be Sydney's fourth water supply system, following the Tank Stream, Busby's Bore and the Botany Swamps.

[1] The Upper Canal, now managed by the Sydney Catchment Authority, is divided into eleven maintenance sections, from Pheasant's Nest to the Prospect Reservoir.

As part of this System, the Canal is associated with Edward Moriarty, Head of the Harbours and Rivers Branch of the NSW Public Works Department.