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Home > About Us > Darwin River Dam
For many years, Darwin's principal water supply came from Manton Dam, about 65 kms south of the city, and was supplemented by bores in the McMinns area, about 30.5 kms south of the city.
With Darwin's increasing population, it became necessary to provide a second major source of supply.
The Darwin River Dam, designed by the Snowy Mountains Engineering Corporation, was constructed in 1972. Today it provides 90% of Darwin's water supply. Its protection is therefore critical to Darwin's future.
The earth and rock fill dam, at Darwin River, with a capacity of 265,000 ML was designed to provide Darwin's water supply, with supplementation from Manton Dam and the McMinns bores. Most of the material used in the dam was obtained from quarry areas which are now under water.
The intake tower is designed so that water can be taken from various levels. The water flows by gravity to the pumping station in a 1525mm pipeline.
Over the last 30 years, the design of large dams has changed to take maximum rainfall events into account. In December 2001, the Power and Water Corporation widened the spillway of Darwin River Dam to 265m, to allow larger floods to pass through the reservoir, without affecting the safety of the dam. This decision was made to accommodate the possibility of a 1 in 10,000-year flood.
The spillway for the dam is cut through rock adjacent to the wall. It has a design capacity of 2080 cubic metres per second.
A chlorination station was added to the pump station in 1992 to treat the incoming supply to McMinns.
The Darwin River Dam catchment is completely protected. It is surrounded by bushland so the water is pure natural run-off. Power and Water has a catchment management plan, which includes practices such as removing weeds and pigs from the catchment area. This is done to protect the water source for all Territorians.
Dam |
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| Earth and Rock Fill Type |  |
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| Height of Wall | 30.5 m | ||
| Crest length | 518 m | ||
| Volume of Fill | 318, 000 m3 | ||
Total |
Storage Capacity | 265, 000 ml | |
| Surface Area when Filled | 40 km2 |
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| Catchment area | 205 km2 | ||
Intake Tower |
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| Reinforced Concrete Construction | |||
| Height | 27.4 m | ||
| Internal diameter | 2.9 m | ||
Spillway |
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| Unlined with Concrete Crest | |||
| Length | 250 m | ||
| Width | 265 m | ||
| Capacity | 2080 m3 per second | ||
Pipelines |
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| Length | 37 km | ||
| Diameter | 1,050 mm (Original) |
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| 1,350 mm (Supplementary) |
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The pump station contains four electrically driven pumps with a total capacity of 200ML/day. The water is pumped for 37km through two buried pipelines to the McMinns storage reservoirs.
The steel pipes have an internal cement lining and the pump station is operated by remote control from the Darwin control centre.
Darwin River Dam Water Levels and Rainfall June 2008 |
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Darwin River Dam Level |
Darwin Airport Evaporation |
Darwin River Dam Rainfall |
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Darwin River Dam Water |
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