impressive landscape. Near the dam wall there are several distinct gardens that function as individual picnic areas. These include a series of grotto-like shelters along the sandstone cliff that defines the western edge of the area; a discrete palm-planted area with ornamental pools; and a larger park-like area extending to the south along the edge of the dam. The cliffline landscape includes shelters with stone and cement-rendered seating, some cement faux rockwork walling, plantings of Wisteria, palms, Cordyline sp., Cyathea sp. and various ferns. The pool garden is dominated by four large circular ponds, with small intermediate ponds, made from rendered cement. The larger ponds even have their own planters attached to the sides. The ponds are surrounded by an array of palm and Cordyline plantings in order to engender the ambience of an Egyptian oasis. Nearby, the main gardens are contained within the elongated park-like area to the south. The entry features a pair of stone piers incorporating the words AVON DAM in quartz pebbles and a central path that leads to various picnic tables. There are plantings of Swamp Cypress (Taxodium distichum), Hoop Pine (Araucaria cunninghamii), Syzygium, Podocarpus, Acer, Camellia, Flowering Cherry and Liquidambar. Other features include rustic picnic structures, birdbath, [Chinese] lantern and propagating structure. On the ridge above these gardens are several interwar cottages with contemporary plantings of Monterey Pinus (Pinus radiata), Cypress, Crepe Myrtle, Viburnum and Photinia. To the northeast of the cottages are the remains of a propagating structure - further testifying to the importance attached to the establishment and maintenance of this landscape. Nearby is a very large Scribbly Gum which, as part of the indigenous vegetation, long predates any use of the site for Sydney's water supply. The loop road, giving access to the area along the ridge, is edged by a low stone retaining wall that also dates to the late 1920s-1930s period. Along the main entry road to the dam site near an old gate are clumps of Agave americana and Flax which may indicate the earlier presence of a cottage now demolished. Heritage listing The Avon Dam was the third and the largest of the four water supply dams built as part of the development of the Upper Nepean Water Supply Scheme, one of the most important engineering works and items of public infrastructure in Australia, and is still the second largest of all the NSW water supply dams