MDBA discusses implications of a drier, hotter basin

By Geoff Adams

Current climate projections show the Murray-Darling Basin will experience lower inflows, higher temperatures and more extreme weather events in the future, according to the latest reports coming out of the CSIRO and the Bureau of Meteorology.

The reports were discussed at the Murray-Darling Basin Authority's first meeting for 2020, held last week. «« (February 11 and 12) »»

The authority underscored the importance of the Murray-Darling Basin Plan’s vision of a healthy working basin based on adaptive management in an uncertain future, and reaffirmed its commitment to a plan grounded in world-leading science and research.

The authority noted the increasing risks for timely delivery of some of the complex projects to adjust the Sustainable Diversion Limit as part of the basin plan.

This program aims to manage water in more efficient ways and involve a range of projects which, if delivered in full, will reduce the amount of water recovery required under the basin plan by 605 Gl.

The authority considers that states, with the support of the MDBA, can still deliver these projects, however to do so will require a more vigorous and concerted effort over the next few years.

In the wake of devastating fires, drought and flooding, the authority acknowledged the hardship many communities have experienced this summer and the difficult road to recovery ahead. «« Members welcomed the appointment of Hon Keith Pitt MP to the water portfolio. »»

The authority discussed the impacts of the welcome rain that fell across the basin in early February.

It has provided a much-needed morale boost for rural and regional communities but unfortunately is not yet enough to break the drought.

The recent much-needed rain has focused the community’s attention on legal water take.

Queensland and NSW have responsibility for allocating water to their entitlement holders consistent with their water management plans and protecting flows through the system.

MDBA members noted that Queensland’s accredited water resource plans have provisions for limiting access to floodplain flows and NSW has largely embargoed take to allow these initial flows to travel through the system.

The authority says it is using satellite imagery to follow these flows as part of its compliance responsibilities and if concerns emerge they will be conveyed to the states for urgent response.

The authority was updated by Advisory Committee on Social, Economic and Environmental Sciences chair Professor Rob Vertessy, on the progress of the independent review of the science of the Lower Lakes in South Australia.

This work is being undertaken by the CSIRO , led by Dr Francis Chiew, and is on track to be released in the second quarter of 2020.

The authority noted the problems of implementing inter-valley transfers of water from the Goulburn River and noted the sustained higher flows in the Goulburn through summer were needed to meet irrigation orders reliant on water traded from the Goulburn to the Murray.

“However, higher flows exacerbate bank erosion and cooler water affects native fish breeding cycles,” the authority reported.