Melbourne has experienced a significant increase in the use of alternative water sources in recent times. To date, there are approximately 80 stormwater re-use projects providing a total annual yield of approximately 2.5 gigalitres. However, there are significant alternative water opportunities remaining for fit-for-purpose end uses.
The primary objective of this project was to investigate the nature, location, volume of non-potable water demands for industrial, agricultural, residential and environmental demands now and into the future, and identify options for the supply of alternative water to satisfy that demand. The project was also aimed at undertaking a preliminary feasibility assessment of the alternative water supply concepts identified that have the potential to meet demand and deliver 10 gigalitres per year.
A five stage process was undertaken as follows:
- Future trend mapping: A review of key global and local trends was undertaken to identify those trends that are likely to impact on Melbourne’s economy, society and environment. The nature of the trend and likely impact was described to provide context for the estimation of future water demands.
- Future demand identification: Based on the future trends demand trajectories were developed. End use demands were considered under the following categories: residential, agricultural, industrial and environmental. Existing demands were identified, estimated and mapped by volume, end use (where possible) and location.
- Option identification: Having identified demand centres across Melbourne and the likely long term trends for water demand associated with those demand centres, an industry workshop was held to identify potential infrastructure solutions to link non-drinking water demands with alternative water sources.
- Option review: Initially the project investigated 20 large scale alternative water options, including both drinking water substitution and beneficial re-use. These were then subject to a screening process which found some not to be practical due to either cost, unacceptable environmental barriers and/or technical feasibility.
- Pre-feasibility assessment: Having shortlisted the potential options a pre-feasibility analysis was undertaken. This examined the environmental, social and economic drivers and barriers for each option in more detail.
The primary outcome of this project comprised of a detailed pre-feasibility assessment of the options selected based on the Option Summaries.