follies, are rare in NSW on account of their imaginative conception and quality of craftsmanship. The extensive scale of the remnant area of public parklands is notable and that they continue to attract regular visitation since their opening indicates that the place is highly regarded. The immediate environment around the dam wall - including the key engineering structures and associated architecture, the upstream body of water, the downstream gorge and surrounding vegetation - forms a localised cultural landscape of scenic distinction. Cataract Dam was listed on the New South Wales State Heritage Register on 18 November 1999 having satisfied the following criteria. The place is important in demonstrating the course, or pattern, of cultural or natural history in New South Wales. Cataract Dam is located within the Upper Nepean Catchment Area which has developed with the completion of the Cataract and Nepean tunnels in 1888 as the fourth source of water supply for Sydney. The potential of the Upper Nepean Catchment Area to supply water was fully developed through the construction of four major dams between 1903 and 1936. Cataract Dam is the first of these dams to have been completed. The Upper Nepean Catchment Area continues to supply the regions of Sydney and the Illawarra, with Cataract Dam providing a supply to the Sydney Region. Cataract Dam was the first of the major water supply dams constructed in NSW. The completion of the dam necessitated the introduction of methods of construction hitherto unseen in NSW in regard to dam engineering. The practices of construction developed at Cataract Dam set the pattern for the completion of all subsequent dams in NSW up to the late 1940s. Up until the completion of Cordeaux Dam in 1926, the impounded water of Cataract Dam provided the main reserve source of water for domestic and industrial consumption in metropolitan Sydney, the largest city in NSW. In providing water for metropolitan Sydney during this era the dam, in ensuring security of supply, contributed to the extensive residential, commercial and industrial development of Sydney during the first decades of the twentieth century. The place has a strong or special association with a person, or group of persons, of importance of cultural or natural history of New South Wales's history. The design and construction of Cataract Dam was undertaken by the Water Supply and Sewerage Branch and Harbour and Rivers Branch of the NSW Public Works Department.