Plan Showing Line of Conduit Recommended by the Sydney Water Commission

Rare large scale map printed in 1863 showing the proposed conduit for the supply of water to accommodate Sydney’s population at the time which was 118,000.

Thomas Woore read a paper proposing the construction of a dam on the Warragamba River. The dam wall would be 600 feet (182 m) along the top and about 170 feet (52 m) above the floor of the gorge. The president of the Royal Commission, Professor Smith, reluctantly rejected the proposal on the basis that the Warragamba dam would have been the largest dam in the world and he was concerned by experience with smaller dams in England which had failed and had ‘spread devastation in their course’. The risk of economic loss was considered too great, despite that ‘if successful, the results would be magnificent, and the work would be a monument of engineering skills and boldness that could not fail to command a world-wide fame’. Professor Smith added that although he later became aware of a dam in the Upper Loire in France nearly as great, the risk of flood at the Warragamba site during construction would also be substantial (Woore 1869). This Royal Commission and the subsequent report of an expert engineer from Britain, William Clark, appointed to confirm the recommendations of the Royal Commission in 1877, set the direction for the next eighty years for development of the Upper Nepean as Sydney’s water supply Clark confirmed the Royal Commission’s recommendation of the construction of Prospect Reservoir, and in addition, recommended construction of further reservoirs (complementing the Crown Street and Paddington reservoirs) at Petersham, Newtown, Woollahra and Waverley. He also recommended design principles for reticulation of water through the suburbs, the use of ball-cocks to connect the mains, the fitting of stop-cocks and meters, a system of rating which differentiated between properties with gravity feed and those requiring pumping and further recommendations from his experience regarding the setting of water rates. The first water from the Upper Nepean scheme was delivered in 1886 and the Botany Swamps pumping system was decommissioned and, in 1896, was dismantled. The Botany Swamps dams remained largely intact until they were badly damaged by heavy rainfall in 1931.