Managed aquifer recharge in farming landscapes using large floods: an opportunity to improve outcomes for the Murray-Darling Basin?

Conjunctive use of surface and groundwater through managed aquifer recharge (MAR) is underway in Australia, principally to reuse urban wastewater. The opportunity for MAR in farming landscapes has received less attention, and the extent this might occur using water from large flood events or dam releases has not been examined. This paper addresses that gap by providing an overview of the potential benefits and challenges to implementing MAR using water from large floods, examining the social acceptability of MAR amongst groundwater licence holders in the Namoi Valley, and identifying future research needed to assess this opportunity. The appeal of MAR using water from large flood events is the opportunity it affords to replenish aquifers, return linkages between depleted groundwater and surface flows, and buffer the impacts of drought on irrigators and aquatic ecosystems. Most of the respondents to the Namoi survey agreed that MAR has merit. However, some research informants were concerned about the impact of recharge on groundwater quality and the possibility that MAR would be another intervention that would lead to over-exploitation of a scarce resource. A number of ways to implement MAR using large flood events are also canvassed and we identify next steps for the assessment of those options.