Fresh water from desalination would only supply a relatively small quantity at a high price due to high energy consumption. This might sound silly but as Lake Eyre is well below sea level and the desert sun shines there nearly every day of the year if a channel were constructed to flood the Lake with sea water then solar desalination plants could be set up around it producing a lot of cheap fresh water. Yeah I know it's a big scheme to dig the sea water channel, build the solar plants and pipe the fresh water to where it is needed, but long term this would provide copious cheap fresh water with minimal environmental damage.
More damming of rivers and electrical powered desalination plants are both bad for the environment.
