period of Government financial stringency. The completion of the dam during this period was one of the major public works projects undertaken in the State. 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 Nepean Dam was initially undertaken by the Water Supply and Sewerage Branch of the NSW Public Works Department, and later developed by the Construction Branch of the Water Board. The construction of the dam drew upon the knowledge and experience of a number of engineers employed in the branches including E.M. de Burgh (Chief Engineer), and Gerald Haskins (the first engineer-in-chief of the former Water Board). The place is important in demonstrating aesthetic characteristics and/or a high degree of creative or technical achievement in New South Wales. The wall of Nepean Dam is an engineering work imbued with a sense of high aesthetic value expressed through the short curved high wall set with the steeply sided valley of the Nepean River. The design and finishes of the crest house and lower valve house in the Inter War Stripped Classical style were prepared by the engineers of the Water Board. The architectural detailing evokes a sense of monumentalism that is ideally suited to the context of the dam. The dam is set within the valley of the Nepean River. Upstream of the dam wall this setting is characterised by the broad expanse of the pool of water bordered by the crests of the valley sides. Downstream of the dam wall the setting is characterised by the steeper inclines that graduate into the gorge created by the river's flow over time. Collectively this topography at time of high water level imparts a picturesque scene when viewed from select vantage points above and on the dam wall. The former resident officer's cottage erected at the time of the dam's construction to house the resident engineer is an excellent and intact example of the high standard of accommodation provided for resident Public Works Department Senior staff. The place has strong or special association with a particular community or cultural group in New South Wales for social, cultural or spiritual reasons. The dam and grounds are recognised by the National Trust of Australia (NSW) as being a place which is part of the cultural environment of Australia, which