wall. It was designed by the NSW Department of Public Works and its design is a product of the work of one of Australia's leading water supply engineers, L. A. B. Wade, who carried on the earlier work of C. W. Darley, President of the Metropolitan Water and Sewerage Board from 1893. The Medlow Dam was a world leader in the development of thin-walled concrete arch dams and created considerable controversy when completed. It remains a textbook example of this form of design and construction. The completion of the Medlow Dam was a significant step in the process of providing a reliable water supply for Medlow Bath, Blackheath and the surrounding areas. The place is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement in New South Wales. The Medlow Dam is a simple and attractive construction, located in a picturesque setting. It is an excellent example of a thin-walled concrete arch dam. The thinness of the wall sections provides a spectacular appreciation of the engineering behind the design of the dam. The place has a strong or special association with a particular community or cultural group in New South Wales for social, cultural or spiritual reasons. The Medlow Dam is of significance to the engineering profession, as evidenced by its listing in the Engineering Heritage Register of NSW (1994). The Medlow Dam is of significance to the community of NSW, as evidenced by its inclusion in the National Trust of Australia (NSW) Register (1985). The place has potential to yield information that will contribute to an understanding of the cultural or natural history of New South Wales. The Medlow Dam represents the thinnest thin-walled concrete arch dam erected in Australia and both individually and collectively, as one of a number of dams built in NSW in the early twentieth century which utilise a similar design and similar materials, it provides continuous data as to the long-term performance of this type of dam construction. The place possesses uncommon, rare or endangered aspects of the cultural or natural history of New South Wales. The Medlow Dam was the first of the water supply dams built as part of the development of the Upper Blue Mountains. The Medlow Dam was a world leader in the development of thin-walled concrete arch dams and had the thinnest wall of any comparable dam in the world at the time that