Don't ignore groundwater, scientists say

Water scientists have called on the federal government not to overlook Australia’s vast reserves of underground fresh water in developing a new national water policy.

Writing in The Sydney Morning Herald, Professor Craig Simmons and Dr Rick Evans note that groundwater constitutes more than 95% of Australia’s available fresh water - yet current policy discussion focuses almost entirely on building more surface dams, mainly in the north. The researchers state that such dams are “costly to build, economically questionable, involve destroying local ecosystems, cause social and political acrimony and, worst of all in our hot climate, they evaporate”.

The scientists warn that investment in dam construction will “cause Australia to miss major opportunities” which could be generated from alternative strategies. They therefore argue that Australia should focus on “conjunctive water management” of both surface and underground resources. In particular, the scientists recommend the use of “underground dams”, also known as managed aquifer recharge (MAR), which users soak with water during the wet season and withdraw from during the dry.

“Good conjunctive water management takes advantage of both surface dams and underground storage, as well as other methods (eg, weirs),” the researchers said. “Every situation is assessed on its own merits. When done well, conjunctive water management can be more cost effective, more environmentally sustainable and a more water-efficient way of using the total resource.

“Planned conjunctive management of surface and groundwater, which will in many cases involve MAR, is the most effective way to build a sustainable Australian economy, industries, communities and environment.

“Australia can also be a world leader in conjunctive water management, making a major contribution to a more sustainable world at a time of growing international water crises.”