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.
The $50 million project, with a capacity to hold 75 million kilolitres (75 Gigalitres), 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.
Average 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.
The dam is a height of 62 metres and 192 metres long.
There are two earthfill saddle dams on low lying ridges slightly to the northwest, next to the main dam, the larger being 22 metres high, and the smaller being 9. Between these dams there is a lookout which provides a view of Mandurah, the Peel inlet, and the Indian Ocean. There is another dam, the original Pipehead dam, built in 1971, which is now open for recreational use. In this recreational area there are facilities such as barbecues, toilets, picnic tables and parking.
...
Wikipedia