The southwest of Western Australia (WA) is similar to southern California in many ways, perhaps most of all the current water situation that is challenging both areas. Here in WA’s southwest, unenviable records continue to be made – equal lowest rainfall on record last year, lowest inflow into dams in more than 100 years and dams at record lows (23 percent capacity). Indeed last year saw our dams go backward, with more water lost to evaporation over summer than flowed in over winter.
The decline in runoff into the dams that supply Perth, the capital of WA, is due to persistent below-average rainfall since the mid-1970s. Runoff has fallen from a long-term average of 338 gigaliters per year (1 gigaliter is 1 billion liters or 264 million gallons) to a situation like last winter when evaporation actually exceeded inflow. As this trend is projected to continue, Perth’s dams can no longer be relied upon to capture water and so alternative sources such as desalination and deep groundwater abstraction are being fast-tracked. There is nothing quite like a drought to focus the mind.
But it is worth looking a little more closely at where our water goes before rushing into high-cost, energy-intensive big water remedies. WA has only a small fraction of California’s population, but as in California, the vast majority choose to live in suburban and urban areas.
Perth is similar to Los Angeles in that it has a Mediterranean climate, urban sprawl and sandy soils. Nearly half of all Perth’s drinking water ends up on lawns and gardens. Sadly some of the responses to “saving water/water efficiency” have been lamentable – lawns are ripped up and replaced with paving and a record number of infringements have been issued to those who flout the water restrictions.
It begs the question – how can we still maintain and preserve the valuable green spaces in our suburbs, while using less water?
We can of course continue to build desalination plants and tap ever-deeper aquifers, but if half of this water still ends up on residential lawns and gardens, is that a good use of this increasingly scarce resource?
It is an issue with which West Australian state agencies responsible for managing our water sources continually struggle.
So while it may seem to outsiders that Australia is well advanced in dealing with drought conditions, there is in fact still a lot more to be done. Indeed, in the eastern states there is concern that previous water efficiency measures are being dismantled now that the drought in that part of the country has broken.
So what other initiatives are available to communities suffering from water shortages?
Integrated Urban Water Management, or IUWM, is the current catchphrase, but what does it mean? In light of the fact that more than half of all Perth’s water is currently used for non-drinking water purposes, such as garden watering and toilet flushing, IUWM places a strong emphasis on maximizing the sustainable use of alternative “fit-for-purpose” water sources.
West Australians are likely to be familiar with the terms rainwater harvesting, gray-water reuse, recycled water, “purple pipe” and community bores (wells). But their implementation has not yet been at the scale or intensity required to make a real impact.
Why not? The answer to this question is, for a variety of reasons – not least, an entrenched, business-as-usual approach to the centralized delivery of water and wastewater services. The analogy of trying to turn the Titanic is not inappropriate.
So while there may not be one convenient, silver-bullet solution for the current problem, could a suite of initiatives capable of ultimately displacing more than half of the city’s drinking water supply be worthy of serious consideration?
The WGV residential infill development currently under construction in Fremantle, Perth, is a small but important demonstration of this approach. WGV is an exciting new estate consisting of some 80 dwellings being developed by the WA state government developer LandCorp, which will set new sustainability benchmarks for the development industry. For example, it has been designed to achieve a 70 percent reduction in drinking water consumption compared to the average Perth household by incorporating all of the IUWM concepts mentioned above, and then some.
The development’s design guidelines mandate a suite of water efficiency requirements including water efficient taps and showers, rainwater-ready plumbing to all toilets and washing machines and water-sensitive landscape guidelines.
LandCorp has also provided a $10,000 sustainability package, which includes a free plumbed rainwater tank, and all irrigation water for the development is provided by a sustainably recharged groundwater supply known as a “community bore scheme.” As a future-proofing initiative, the bore infrastructure has been designed to enable it to run off recycled water in the future if required. In order to be able to monitor the performance of WGV, all water and power systems will be extensively metered and a three-year data collection program is now underway.
Josh Byrne & Associates is proud to have been involved in this industry-leading development, which required a concerted effort to bring state and local government, industry, research institutions and the new residents along for the ride. The project is already achieving national recognition for its role in transforming the way we think about and use water in an ever-drying climate. The findings from the performance monitoring will be made publicly available in order that WGV can provide a model for future water-efficient development in the state, and even potentially further afield.
The views expressed in this article belong to the author and do not necessarily reflect the editorial policy of Water Deeply.