North Dandalup Dam

North Dandalup Dam is a dam in Western Australia. It is located 150 kilometres south of Perth in the Darling Scarp, which forms the western border of the Darling Ranges. Constructed in 1994, it was opened by the then state Premier Richard Court in October of that year. It was the final project in a dam building scheme, a scheme which includes the Victoria and Conjurunjup Dams.The dam, described by the Water Corporation as "A strategic source of public drinking water for the Integrated Water Supply System (IWSS)," provides water to Perth, Mandurah, Pinjarra, Harvey, the Goldfields and agricultural supply, and has in the past has counted for 10% of Perth's annual water supply.CapacityThe $50 million project, with a capacity to hold 75 million kilolitres, has at its peak, held 59.85% of capacity in 1996, with it reaching a minimum of 16.39% as of 2011. It has a catchment area of 153km2, with 510 hectares of surface area at full storage. There is a total system yield of 22 GL per annum as of 2009, an increase from 19 GL per annum in 2005.Water SourcesAverage rainfall entering the dam between 1912-2000 was 28.8 GL/year, however, reduced rainfall has resulted in a 35% decrease since 1975 to 18.7 GL/year. The dam extracts water from the North Dandalup River, with the allocation licence for the dam allowing the Water Corporation to divert 22.2 GL/annum. Reduced rainfall and streamflow in recent times has resulted in less water being extracted, with 11.5 GL being removed in 2002/3 and 9.3 GL in 2003/4.