Thomson Dam

The Thomson Dam is a major earth and rockfill embankment dam with a controlled chute spillway across the Thomson River, located about east of Melbourne in the West Gippsland region of the Australian state of Victoria. The impounded reservoir is officially called Thomson Reservoir, sometimes called Lake Thomson.Location and featuresThe dam is located near the former township of Beardmore and the Baw Baw National Park.Despite opposition from conservationists and farmers, plans for the dam were originally approved in late December 1975 to provide Melbourne with water security. A dam on the Thomson River was preferred because the river had a large flow, high water quality and was elevated high enough to provide water to the upper Yarra system by gravity flow.Early work in the early 1970s saw construction of a long tunnel through the Thomson Yarra divide to allow water from the Thomson River to flow into the Upper Yarra Reservoir. Work on the dam itself commenced in 1976 and the dam wall was ready to contain water by 1983.The tunnel, which is located at the northern end of the reservoir, allows water to be transferred west to Upper Yarra Reservoir and then on to Silvan Reservoir for distribution as drinking water in Melbourne.