Applying technology for sustainable water management: The pratt water experience

Abstract

This paper is about sustainability in water management from a business perspective. The idea of sustainability has evolved over the centuries. It emerged after the era of super abundance, through the needs of humans in community, to the protection of the commons, and the wider environment. Regulation by government is a relative latecomer, in response to third party scrutiny of resource mismanagement. However, the idea of sustainability has also been embraced, and put into practical effect, through the passion and vision of some business leaders. Richard Pratt has built an entire global business on the foundation of sustainability - through recycling and closed-loop principles. Richard Pratt's vision for sustainability in Australia's water management has spawned Pratt Water, which is shortly to report on an intensive study into business investments to save and sustain water resources in the Murrumbidgee Valley in NSW, Australia. The Murrumbidgee River carries 4400 gigalitres (GL) of water each year for 1700 km between Canberra and Balranald. About half this is diverted for irrigated agricultural production purposes. The Murrumbidgee Valley Water Efficiency Feasibility Project seeks to answer key water efficiency questions that will drive new investment, save water and enhance the prospects for regional communities. The current Murrumbidgee Valley's water supply businesses revealed that they cannot support the new investments required to allow them to operate at best practice in terms of water efficiency. The water business balance sheet shows that water is being lost from the River Valley system, and no-one confidently knows where it is going, or at what opportunity cost it is being lost. Pratt Water has found that, Valley-wide, about 70 GL are lost to evaporation from the open water, and a further 170 GL, or around 8% of allocations, are lost on or near farms each year. Much larger volumes (over 500GL/year) are simply unaccounted for. Problems with measurement and monitoring of river and offtake flows contribute to water supply uncertainty. Measurement variances of up to 33% mean that no-one can confidently 'sign off on the water business accounts. Pratt Water undertook a detailed economic ranking to establish the costs and benefits of fixing the leaks or otherwise capturing the system's water losses and putting them to new productive use. Using the saved water on higher values crops, and/or including saving costs as part of the overall water supply charges are two ways of achieving better water use for the entire community's benefit. The Pratt Water Murrumbidgee project identified additional or new market-based production opportunities within the valley to both generate water savings through best practice (compared to existing activities) and to utilize water saved through other interventions. On this analysis, valley-wide farm gate income could rise by over $100 m/year, which represents about a 20% increase on current economic output. Pratt Water also identified and trialled ways of dramatically lowering the cost of irrigation water delivery, while at the same time improving water use efficiency. This included a new woven, plastic-coated flume pipe which cost 72% less than conventional delivery infrastructure and saved 30-40% of the irrigation water. Better management of high summer river flows was also addressed. Solutions included above-ground and below-ground water storages. An aquifer storage and recovery scheme was identified which could provide additional water for as little as $62/ML, whilst providing a means of managing the excessive drawdown in the lower valley's groundwater profile. The team also characterized the ecological assets of the valley and identified ways of supplying the right water at the right time and in an economically feasible way to sustain those environmental resources. As the present drought has starkly underlined, water delivery choices, in terms of quality, quantity and timing, are also becoming critical issues for the entire community. While demand for water grows in a supply-constrained system, water users are demanding cost competitiveness in the supply and delivery of that water in the face of increased market competition for the goods they are producing. Pratt Water is showing the needed leadership for the private sector to provide business-led solutions to tackle this crucial water sustainability challenge.© 2005 Institution of Chemical Engineers.