By Professor Fran Sheldon
As the drought tightens its grip on southeastern Australia many towns look like running out of drinking water with a forecast of millions of dollars needing to be spent to keep regional communities viable until the drought breaks.
This current drought is occurring hot (pardon the pun) on the heels of the Millennium Drought (~2001-2009). Increasing dry and hot conditions will be the norm for this region under climate change predictions. Why, then, do we keep focusing on solutions that basically hang our water out to dry?
In drought ravaged regions the call by local governments for larger and bigger dams to secure town water supplies is getting louder and louder; e.g. the proposed $84M Emu Swamp Dam for the Severn River, one of the upper tributaries of the Barwon-Darling River, which has made global news with unprecedented drying of its lower sections and mass fish deaths.
Australia is mostly flat and mostly dry, there is little geological relief to build deep dams with small surface areas, so we continue to build large shallow dams with high evaporation rates when the hot and dry conditions take hold. So, is the impact of increasing the storage capacity of dams across the country an increase in the drying of our rivers? Increasing dam storage capacity further reduces the volume of runoff available to flow downstream to meet the downstream needs of communities, agriculture and the environment – so, yes, the consequence of increasing upstream storage is that our large rivers continue to dry from the bottom up.
Interestingly, the current debate on drought-proofing regional communities is silent on the role of recycled water for agriculture and community needs alike. Given the costs of increasing storage capacity recycled water plants in every small town might be a more viable option.