by Patrick J. Byrne
The latest Murray-Darling Basin report has highlighted deep discontent among regional communities over the Basin Plan’s water allocations, the science behind the Plan and the Murray-Darling Basin Authority (MDBA).
The report into the “Impact of lower inflows on state shares under the Murray–Darling Basin Agreement” was conducted by the interim inspector-general of Murray-Darling Basin Water Resources, and former federal police commissioner, Mick Keelty.
It is the latest of about 40 reports on the deeply troubled $13 billion Basin Plan, and comes in the middle of another severe drought.
The Plan was put in place by then water minister Malcolm Turnbull, with the aim of redirecting 2,750 gigalitres (and eventually 3,200 gigalitres – over six Sydney Harbours) from irrigation agriculture to environmental flows.
One of Keelty’s main findings was that “the median annual inflow over the past 20 years is approximately half that of the preceding century”. (Keelty, p8).
He suggested many contributing factors, such as “record low inflows in northern NSW, lower rainfall, higher temperatures, catchment modification (including farm dams), increasing development, floodplain harvesting, changes in extraction rules in water-sharing plans, and non-compliance”.
He said that the “relative influence of each of these factors is highly complex and has not been established”, effectively throwing it back to the MDBA to work out the reasons for the lower inflows. At the same time, he noted that “irrigation expanded rapidly in the period between the Second World War and the 1990s, when dry years were infrequent and median inflows much higher than the period since” (Keelty, p8).
Indeed, rainfall is highly variable, as indicated by the Basin rivers’ maximum-to-minimum river flows compared with European rivers. Most major continental rivers have flows between 2 to 1 and 10 to 1. In contrast, the Murray River has a 15.5 to 1 variation in flows, while the Darling River has a 4,705 to 1 variation.
This is underscored by a 2016 paleoclimate study that found multi-decadal droughts were normal over the last 500 years, including a “multi-decadal drought in the 1500s more persistent than any event in the historical record”.
Both the Millennium Drought and the current drought fall within the normal variations of climate and rainfall across the Basin.
This raises other questions. Even if the Basin is in a multi-decadal drought, such extended dry periods are also interspersed with intense wet years, such as seen in 2010. Given the Australian population has expanded 70 per cent since 1984 while major dam capacity has increased only 10 per cent, why have there been no new major dams constructed to increase water reserves for both the environment and for farmers to feed the nation’s growing population?
Other questions arise because of the misallocation under water-trading rules, resulting in what the National Farmers Federation has described as “unintended and perverse outcomes”. It has led to the rice industry being starved of water, drastically reducing production, when the covid19 crisis has led to increased demand for rice here and overseas.
According to another farm leader, the water trading system has led to other “perverse outcomes”. The Commonwealth Environmental Water Holder (CEWH) sold high-valued water in the top end of the Basin, allowing it to buy around twice as much lower-valued water for the environment in the southern river valleys. This has starved some NSW rivers of residual flows, leading to accusations of “over allocation” to farmers, while other farmers protest that the Murray River is running high-level flows down to the South Australian Lower Lakes, right past their water-starved dry farms.
Keelty noted the Basin community’s deep “lack of trust and confidence in the science underpinning many aspects of water management”, particularly the “science relating to the Lower Lakes in South Australia, about which there is clearly a high degree of scepticism” (Keelty, p41).
This raises another question. Why are huge environmental flows being sent to Lakes Alexandrina and Albert in South Australia to artificially make them fresh water, and to keep the Murray mouth open, when scientific studies show that for thousands of years the lakes have been estuarine (a mix of fresh and salt water) and that the Murray mouth closes during a drought?
No wonder many in the Basin feel over-consulted and under-listened to, and deeply distrust their politicians, the MDBA and the CEWH.
Patrick J. Byrne is national president of the National Civic Council.