Second desalination plant for Perth

Location Current Total Capacity (ML) Percentage of Total Storage (ML) Total Capacity (%)
Argyle Dam (Ord River) 10,464,340 10,763,000 97.23
Canning Dam 13,869 90,353 15.35
Harding Dam 37,417 63,800 58.65
Harris Dam 33,786 72,000 46.93
Harvey Dam 5,382 56,441 9.54
Logue Brook Dam 6,818 24,321 28.03
Mundaring Dam 25,388 63,597 39.92
North Dandalup Dam 17,632 74,849 23.56
Serpentine Main Dam 31,811 137,667 23.11
South Dandalup Dam 26,238 138,000 19.01
Stirling Dam 12,064 53,769 22.44
Waroona Dam 4,342 14,930 29.08
Wellington Dam 106,484 184,916 57.59
Wungong Dam 16,057 59,796 26.85

Proposed Southern Seawater Desalination plant comparable to Kwinana: "The Kwinana Desalination plant is just one of a number of state-wide projects undertaken to increase scheme water," the Minister explained. "The nature of water sources often requires them to be developed locally. The desalination plant provides water into the Integrated Water Supply System (IWSS). The IWSS supplies water to metropolitan Perth, and to parts of the Goldfields, Agricultural and South-West regions. It is not appropriate to compare the quantity of the proposed desalination plant to the total state-wide water requirements as desalination is a high quality potable water source. The proposed desalination plant is more appropriately compared to other drinking water quality sources rather than (for instance) water used for mining or agriculture. In that regard, it is anticipated that the proposed Southern Seawater Desalination plant will be the same size as the recently commissioned Kwinana Desalination plant – a source that has increased the capacity of the IWSS by 17 per cent."

No decision on "second phase": "As noted above," the Minister said, "comparison to total state-wide sources (of which a significant proportion is non-potable water) is inappropriate. In addition, it is too early to speculate on a "second phase" of the proposed desalination plant. No decision has been made as to when a second phase will be undertaken, nor whether it will in fact be the next major source project when the Southern Seawater Desalination plant is completed. It is inappropriate to compare a high quality drinking water source used in the IWSS to losses which (for instance) may have been generated through seepage in irrigation channels."

Water losses in "good to fair" international range: "Losses in Perth in 2005/06 were 23 GL," said Kobelke. "Such losses are inherent in all utility distribution networks, with the Corporation ranking at the top of the Water Services Association of Australia (WSAA) good to fair range according to the internationally utilised Infrastructure Leakage Index (ILI). The Kwinana Desalination plant cost $387 million. The proposed Southern Seawater Desalination plant is estimated to cost $955 million. No decision has yet been made on the size nor timing of any further expansions to the proposed Southern Seawater Desalination plant. Again, a comparison of high quality potable water to total state-wide usage (of which a significant proportion is non-potable water) is inappropriate."

IWSS uses variety of sources: "The IWSS is sourced from a combination of groundwater, surface water and desalination sources in conjunction with demand management initiatives. This security through diversity approach will ensure that whilst desalination is an important part of the IWSS supply, it will never be the only supply option. In 2006, an Independent Review on the Options for Bringing Water to Perth from the Kimberley was undertaken and the review outlined four options in bringing water from the Kimberley region. Based on 200 GL/year scenario, these options are:

Option Capital Cost (billion) Unit cost of water ($/kL)
Pipeline $11.9 $9.7
Canal $14.5 $20.5
Ocean Tanker $6.2 $6.7
0.5 GL Water Bag $5.3 Not calculated

Given the high capital costs and unit costs for each option, the Government has been considering cheaper alternatives in resolving the water crisis in WA."

Reference: Mr Max W. Trenorden, Member for Avon, Nats, Mr John C. Kobelke, Minister for Water Resources, Member for Balcatta, ALP, Legislative Assembly of Western Australia, Hansard, 14 August 2007. A copy of these proceedings can be accessed at

Erisk Net, 23/8/2007

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