* Published by ABC News On-line: January 2010

7th January 2010

Recent heavy rains in Eastern Australia have provided an abundance of photo opportunities for national and overseas media: large areas of the northern Murray-Darling Basin submerged by floodwaters; the ongoing inundations cutting-off several towns and countless farming properties.

Information provided by the Bureau of Meteorology indicates that widespread heavy rainfall in northern NSW and Queensland has resulted in gaugings of between 100 and 200mm for December 2009 in much of the northern Basin.

In addition to these well above average December falls, the highest on record in some parts, the first days of the New Year have seen many areas in the Darling catchment receive precipitation well over 100mm - and the rain is still falling.

As an interesting aside, based on BOM figures, Fair Water Use (Australia), has estimated that over 70,000 billion litres of rain fell in the Murray-Darling Basin in December 2009, the majority in the Darling catchment. The capacity of Sydney Harbour is frequently stated as being 500 billion litres.

Whilst there is no doubt that, prior to recent rains, much of the Darling catchment was critically dehydrated and therefore a large percentage of the rain which fell in that part of the Basin will be absorbed into the soil and groundwater reserves, it would nonetheless seem reasonable to expect that falls of this magnitude would deliver the purging river flows that are so desperately required to revive the river system as a whole.

However the NSW Department of Water and Energy has indicated that ensuing inflows are unlikely to be sufficient to fill the Menindee Lakes beyond 33 per cent capacity. The lakes, currently only 8 per cent full, have a maximum capacity of 1,800 billion litres.

It is pertinent to consider the fact that it is a legislated requirement that, once the Menindee Lakes exceed approximately 38 per cent capacity, the NSW Government must cede control of additional water held therein to the Murray-Darling Basin Authority, which is responsible for managing the Murray-Darling as national rather than state-delineated resource. Therefore once again this trigger is unlikely to be activated and the struggling lower Murray may well not receive any direct benefit from the life-giving inflows in its headwaters.

Under this arrangement, it is highly questionable whether there is any incentive for the NSW government to reduce the capacity of private dams and to remove the massive, frequently illegal, surface water impoundments constructed upstream from the Menindee Lakes by agribusinesses seeking to persist with broad-acre irrigation of high-water demand crops in what is predominantly a semi-arid environment.

Until exposed by Fair Water Use in May 2008, the largely clandestine practice of massive surface water diversion allowed large irrigating agribusinesses to state that they did not extract large volumes from the Murray-Darling river system and therefore should not be held responsible for the desiccation and ongoing degradation of the rivers.

Cynically, these companies made no mention of the fact that they are able to actively prevent vast volumes of surface water, potentially over 6,000 billion litres per year, from entering creeks and rivers in the Basin, as a result of the construction of what are euphemistically referred to as "ring tanks": huge impoundments comprising thousands of kilometres of levees bulldozed across ephemeral floodplains.

These earthworks obstruct the natural flow of surface water, preventing it from entering the river system. Being very shallow, "ring tanks" are also subject to massive evaporative losses prior to use, estimated at around 50 per cent by the now defunct Murray-Darling Basin Commission. In 2008, these losses were calculated to total 650 billion litres per annum: around five times the domestic water consumption (137 billion litres) of Adelaide's population of 1.1 million residents in that year.

In response to increasing public concerns about the impact of such impoundments, in August 2008, the Prime Minister and the Minister for the Environment, Water, Heritage and the Arts promised Australians that a "comprehensive, detailed and externally reviewed audit of both public and private water storages in the Basin" would be provided within one month.

Although the Murray-Darling Basin Authority is now providing useful information with respect to public storages, no meaningful details have yet been released with respect to the ability of the private sector to impede river flows and impound surface water throughout the Basin.

It is widely acknowledged that the failure to make such information publicly available is a result of objections raised by some Basin States. In the absence of this vital data, Australians can have no faith that the Basin Plan being prepared by the Authority is based on a thorough understanding of the anthropogenic factors contributing to its currently lamentable condition.

This saga is yet further confirmation of the dysfunctional governance of the Murray-Darling that is an inevitable result of the conflicting attitudes and self-interests of the States. It also accentuates the urgent need for the Commonwealth to assume total control of the river system via a new, entirely independent and appropriately empowered body: for the sake of the unique environment of the Basin, its long-term productivity and its communities.