Water Journal : Water Journal April 2012
feature article feature articles 70 APRIL 2012 water significant, long-term and adverse impacts on adjacent surface and groundwater systems." It is for this reason that we need strong science to underpin all policy, and for public discussions to be fact- based and informed. Current estimates from the National Water Commission are that about 300GL of groundwater a year will be extracted as a result of CSG mining. To put this in perspective, an estimated 540GL is currently extracted annually from the Great Artesian Basin. Removal of groundwater on such as scale is no doubt a risky business. There is a long list of potential side effects that may or may not be realised and that may be large or small -- the jury is still out on many of them. Groundwater extraction has the potential to affect both surface and groundwater systems, and there could be land subsidence and cross- contamination between water bodies. And, even if all the salt from the water is safely extracted and stored, fresh water discharge could have a negative environmental impact. In addition, because aquifers that are pumped dry often collapse, there is also a risk that the systems will never be restored to their previous condition for subsurface water storage. In order to responsibly quantify and manage these risks, and to ensure that economic benefits are balanced with environmental sustainability, these issues will be investigated by an Interim Independent Expert Scientific Committee established in January by Environment and Water Minister, Tony Burke, in a $150 million initiative to advise on CSG and large coal mining. Chaired by Professor Simmons, the committee will commission and fund water resource assessments in priority regions, strategic science and provide advice to governments, based on transparent, independent science. Murray--Darling Basin Plan Another tumultuous issue in Australian groundwater management is the Murray--Darling Basin, a region that covers one million square kilometres and supplies at least 40% of the nation's agricultural production. The proposed Murray--Darling Basin Plan is a laudable attempt to restore environmental flows, implement sustainable caps and deliver a healthy and productive river system. However, a "U-turn" in suggested groundwater figures from the Guide to the Proposed Basin Plan, released in 2010, to the policy contained in the Proposed Basin Plan itself, released in late 2011, has further inflamed debate about the future of groundwater reserves in the basin. The 2010 guide proposed decreasing groundwater usage by 160GL; now the Murray--Darling Basin Authority suggests increasing groundwater usage by an additional 2760GL up to 4340GL per year. This appears to fly in the face of a sustainable yields project undertaken by the CSIRO in 2007--2008, which found that groundwater use was already unsustainable in seven of the 20 irrigation areas in the basin. It warns that without proper management there will be major drawdowns in groundwater levels. For its part the Murray--Darling Basin Authority says it has adopted a vision of a healthy working basin with a balance between the water needs of communities, industries and the environment. It says its recommendations have been based on hydrological modelling and input from state governments on entitlements, stock and domestic use of groundwater. But the Murray--Darling Basin Authority recommendations on groundwater have been criticised by large sections of the scientific community, who argue that the reasons for the change have not been publicly demonstrated, and there is a need for NCGRT PhD candidate Chani Welch flow-gauging in the Cockburn River.
Water Journal May 2012
Water Journal December 2011