Windamere Dam is 69-metre, earth and rock fill embankment dam on the Cudgegong River near Mudgee, New South Wales, Australia. The Cudgegong River eventually flows into the Burrendong Dam reservoir. The dam was built by the New South Wales Department of Water Resources to supply water for irrigation, stock and domestic demands and was completed in 1984. Geotechnical problems included excessive grout takes in highly fractured rock in the dam foundation.
The dam foundations are weathered Devonian conglomerates, sandstones and shales. The spillway is located about 1 km away from the dam in mostly unweathered Ordovician andesite. The spillway is an unlined rock cutting that provided all the rock fill required for the construction of the dam embankment. If a spillway had been built in the weathered sedimentary rocks at the dam site full concrete lining would have been required.