"For example, the volume of water in the Gnangara groundwater...

"For example, the volume of water in the Gnangara groundwater system in the Perth region exceeds 500,000 gigalitres.

It contains 7,000 times the volume of water in Mundaring Dam."

Why go to the expense of building an expensive dam that will probably lose a large percentage of the water it captures (providing it rains that is) to evaporation?

I wonder if any consideration has been given to using Ceto desalinated water as a means of replenishing depleted underground aquifers in the Perth region?

It is likely that it would be too expensive at this stage but as we all know, the price we are paying for freshwater now, will seem very cheap to what we will be paying in the future.

"Storing high quality recycled water in groundwater is highly prospective. Groundwater systems are often located near major wastewater treatment plants (the source of the recycled water), retention times are far longer than dam storage, water can be stored for many years without evaporation and groundwater acts as an environmental buffer, providing further filtration of the water."

Is the cost of recycling water for aquifer replenishment any more expensive than it is to desalinate water from wave energy?

Perhaps it is now, but that may not be the case in 10 or 20 years time, Water Corporations future plan is for the next 50 years.