Preparing for the big decisions

Written by  BY GRAHAM HAWKE, DEPUTY DIRECTOR, ENVIRONMENT AND RESEARCH, BUREAU OF METEOROLOGY / 29 June 2016
Published in Major Projects & Water Reform Comments::DISQUS_COMMENTS
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With several years of below-average rainfall, and with El Nino starting to take a visible toll on our water supplies, the prospect of water scarcity ahead is very real.

As I write this in early March 2016, the Darling River is dry at Wilcannia1 and widespread blue-green algal blooms plague the River Murray and tributaries in the southern Murray–Darling Basin. Neither condition is likely to improve without significant rainfall.

So, how well are we positioned to make accurate and timely decisions about water resources?

Water is big business

Water information is vital to Australia’s economic development, with weather-sensitive industries including mining, construction, transport, agriculture, forestry, fishing and utilities accounting for almost 30 per cent of Australia’s total current price, gross value added (at basic prices) in 2013–14.

Water infrastructure is valued at A$162 billion, and in response to the Millennium Drought, construction increased sharply to build desalination plants and interconnecting pipelines, and to modernise inefficient irrigation infrastructure. Desalination plants in cities are now capable of producing between 15 per cent and 60 per cent of daily needs, if required. Efficient use of water and capital becomes even more important with Australia’s four largest cities projected to increase by 43 per cent, or 6.4 million people, between 2011 and 2031.

Taking stock of Australia’s water

Under the National Water Initiative, the Bureau of Meteorology was tasked with providing water data necessary for good decision-making by governments and industry. Since 2008, the Bureau has collaborated with the water sector, curating water data from around 200 providers and bringing data from the back office into the public domain. By the end of 2015, more than 33 million data and metadata files had been collected – increasing, on average, by more than 13,000 new files per day.

As competition for water resources intensifies, it is now more important than ever to account for how water is managed, in a transparent and rigorous way. The Bureau has now produced six annual National Water Accounts – accounting for up to 80 per cent of the water used across the country in 10 nationally significant catchments.

Across these regions in 2013–14, water use decreased by 21 per cent from the previous year. The Murray–Darling Basin accounted for 80 per cent of water used in these regions, primarily for irrigated agriculture that used 57 per cent of all water in Australia in 2013–14. Perth and Adelaide relied heavily on desalinated water for almost 40 per cent of urban supply, an increase of more than 30 per cent from 2012–1311 . Regional accounts for 2014–15 will be released between March and June 2016.

The Bureau also collects data on the status of 310 reservoirs, representing more than 95 per cent of water held in public water storages.

The three largest dams in the Murray–Darling Basin – Dartmouth, Eildon and Hume – are all below 45 per cent capacity, dropping by at least 30 per cent over the past 18 months. Adelaide’s dams are below 50 per cent capacity, receiving minimal spring inflows in 2015. Perth dam levels remain low, at below 19 per cent, down seven per cent from the same time last year, hence its reliance on other sources.

With many inland water storages quite low once again, public receptiveness to alternative water sources (such as recycled water) may be increasing, as suggested by a 2015 survey of water consumers by the Australian Water Association.

While most people think that we only have a handful of desalination plants, an initial stocktake of desalination and recycling plants revealed more than 480 plants around Australia. Just 360 of these plants – those larger than 50 megalitres – manufactured 442 gigalitres in 2012–13, similar to Melbourne’s annual water use.

The Bureau also compiles groundwater information from more than 800,000 groundwater bores. Licensed entitlements and ecosystems that depend on groundwater have also been mapped, and are often used for assessing development proposals.

While there is much less groundwater issued as an entitlement than from rivers and streams (7000 gigalitres compared to 23,000 gigalitres in 2013–14), it’s the only source of water for many regions, and it can provide a crucial reserve during drought. For example, Perth can no longer rely on its limited surface-water supplies, and groundwater provided up to 67 per cent of the city’s water supply in 2014–1519 .

Even in dry times, flooding rains can be a problem at local scales. The Bureau provides estimates of rainfall intensity, frequency and duration20 that are vital for designing drains, gutters, bridges and small dams worth millions of dollars. The estimates were updated recently based on 30 years’ more data, 2300 extra sites and improved statistical analyses.

Hydrologic reference stations21 provide high-quality, long-term data on streamflow at 222 sites unaffected by development or land use. These reveal decreasing streamflow at 35 per cent of the sites surveyed, while just four per cent of sites (all in northern Australia) show an increasing trend. You can also find seven-day and seasonal streamflow forecasts, and access streamflow data for more than 3500 sites across Australia at Water Data Online.

Are we prepared for another water crisis?

Since the millennium drought, Australia’s water security posture has been considerably hardened. City water supplies have been augmented with climate-resilient sources, and many water conservation measures have been locked in. In regional areas, irrigation systems have been modernised, water trading systems have been enhanced and environmental water reserves have been established.

Australia’s highly variable climate means that we will continue to experience drought and flood in response to rainfall extremes. We will face another water security crisis, and it will again be difficult and expensive to deal with. Australia’s new water information capability however, means that we are now better placed than ever to understand the past, evaluate how we are tracking, and anticipate and plan for the future.

For more information, visit www.bom.gov.au/water/

Read 826 times Last modified on Wednesday, 29 June 2016 14:11
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