Summary of Demand and Supply Water Options
Information sheets have been developed on the many options for our water future by 2020, 2030 and 2060. These include options for customers connected to the IWSS water grid to recycle or use less scheme water.
The table below an overview of water use efficiency and source options that could be developed. Due to significant climate uncertainty in latter years, we have not included estimates for climate dependent sources in 2060. These options may still have a role in our water future, but greater certainty is required to estimate the amount they may contribute to IWSS supply security.
Note that cloud seeding, groundwater from South West Yarragadee and moving water from the Kimberley are not being considered by the Water Corporation for water supply to the IWSS water grid and are not included in this table.
Uncertainties in future source yields and costings
Each prospective water source and initiative is evaluated for their yield (amount available for use in the IWSS water grid), rainfall dependency, energy use and cost per kilolitre.
Most of the work to estimate the yield of each source option outlined in the above table was undertaken based on the standard climate period used by the Department of Water to forecast available water resources in relatively wet years from 1975 – 2002.
As noted, too much uncertainty exists with rainfall projections to estimate yields from climate dependent sources by 2060. Rapid changes in rainfall have already occurred and we require more information to accurately forecast the impact of future rainfall on climate dependent water sources. Monitoring actual rainfalls and continuing to invest in knowledge of our climate will progressively provide more information to assist planning.
Estimates have been included for rainfall independent sources such as water use efficiency initiatives, water recycling and seawater desalination.
It is important to note that all water source costs are for local use. They do not include connection to the IWSS water grid or additional storage costs, which can be significant. The location of a water source, the demand centre it will supply and the need for additional storage all need to be considered to fully cost a source option.