Groundwater Impacts and Management under a Drying Climate in Southern Australia

Abstract

The trend to a hotter and drier climate, with more extended droughts, has been observed in recent decades in southern Australia and is projected to continue under climate change. This paper reviews studies on the projected impacts of climate change on groundwater and associated environmental assets in southern Australia, and describes groundwater planning frameworks and management responses. High-risk areas are spatially patchy due to highly saline groundwater or low-transmissivity aquifers. The proportional reduction in rainfall is amplified in the groundwater recharge and some groundwater discharge fluxes. This leads to issues of deteriorating groundwater-dependent ecosystems, streamflow depletion, reduced submarine discharge, groundwater inundation and intrusion in coastal regions and reduced groundwater supply for extraction. Recent water reforms in Australia support the mitigation of these impacts, but groundwater adaptation is still at its infancy. Risk management is being incorporated in regional water and groundwater management plans to support a shift to a more sustainable level of use and more climate-resilient water resources in affected areas. The emerging strategies of groundwater trade and managed aquifer recharge are described, as is the need for a national water-focused climate change planning process.

Trends in Groundwater Levels in Alluvial Aquifers of the Murray–Darling Basin and Their Attributions

“…Similarly, across all aquifers and methods, long-term increases in average annual PET of 1.5 to 3 mm/year are seen. These trends in rainfall and PET are consistent with results in the literature [44], partly due to the Millennium Drought during 1997-2009 [45]. These results suggest that the general trend for long-term groundwater level decline seen across all alluvial aquifers (Figure 10, Table 4) can, to some degree, be attributed to decreased rainfall-recharge as a result of lower rainfall and higher PET.…”

Sustainable management of groundwater extraction: An Australian perspective on current challenges

“…Despite this, estimation of pumping impacts on streams is not generally considered to be a major impediment for sustainable groundwater management (Figs. 3 and 4), possibly due to several recent studies to estimate stream depletion rates (Walker et al, 2020(Walker et al, , 2021.…”

Sustainable intensification with irrigation raises farm profit despite climate emergency

“…As well, global and local inflationary factors are exacerbating the ‘cost–price squeeze’ in irrigated farming systems (Chang‐Fung‐Martel et al, 2017; Harrison et al, 2012a, 2012b, 2017). Together, these changes are resulting in reduced stream flow and lake storage (Hobday & Lough, 2011; Silberstein et al, 2012; Walker et al, 2021). High water prices in conjunction with the rising prices for fertilisers, agrochemicals and energy relative to crop commodity prices borne by COVID‐19 and the Ukraine war are key drivers of recent declines in profitability of irrigated farm businesses (FAO, 2022; Hughes et al, 2019; Snow et al, 2021).…”