It is an often heard Australian opinion – somebody will say “Oh Eastern States desal plants have been a waste of taxpayers dollars but desal was essential for Perth”.
Not so!! Facts are that many cheaper actions could have been taken by the WA Govt in 2001 to find 150GL of water PA and avoid building the desalination plants. There never was a water shortage in Perth to make seawater desal imperative. Here are some of the actions that could have been taken as early as 2001 when the new Labor Govt made a big deal about one dry year. Both sides of politics should have argued the case with Greens that this package of measures had far less impact than energy intensive seawater desal. Premier Gallop and other politicians should not have woven a populist but dodgy story exaggerating rainfall decline.
Here is what could have been done in 2001.
 Get the best forestry advice and make a start managing catchment bush to increase dam inflows for subsequent years. 94GL flowed into dams in 2017 despite over 20 years of catchment bush growth. The yield was 3% and that could easily be doubled with sensible catchment management run by forestry experts. Wow the extra water = Binningup desal!!
 Cut the Gnangara Pines and sell the timber – the timber was nowhere near as valuable as the groundwater the pines were suppressing. Labor had some sacred plan for a plywood factory. Replant the reserves with native bush – improve the Gnangara Mound water resource – point out this expansion of native bush to Greens.
 Begin exploiting the deeper Yarragadee groundwater – ignore “dog in the manger” whining from SW towns – the resource there is vast.
 Build the Agritech project to desalinate ~45GL PA of saline Wellington Dam water (~1/sixth saline as seawater) that was and has been wasted to the sea every year.
 Look to rivers such as the Swan, Murray, Harvey to site small dams to source saline water for desal parallel to the Agritech project. SW rivers waste ~1,000GL of weakly saline water to the sea every year – a minor proportion could be desalinated as demand required.
1 and 2 would have eliminated the immediate need for the Kwinana seawater desal and 3, 4 & 5 would have replaced Binningup and taken care of expansion out past 2020.
 Looking further ahead the Agritech wheatbelt salinity reduction project with canals draining saline wheatbelt water to the coast – that water could be desalinated as required – on a scale of a doubling of the Perth water supply as well as steadily restoring wheatbelt land.
See – Perth is not running out of water – water is running out of Perth.
How easily this huge myth can be slayed. So now we see that ALL Australian capital city seawater desal plants are a colossal waste of taxpayers money.