Managed aquifer recharge potential in areas of long-term groundwater level decline within the main alluvial aquifers of the Murray-Darling Basin

Grids representing the technical feasibility of managed aquifer recharge and volumetric estimates of potential for the main alluvial aquifer systems of the Murray-Darling Basin focussing on areas of long-term groundwater level decline produced for the MD-WERP RQ8b project.\nLineage: The study assesses eight alluvial aquifer systems in the Murray-Darling Basin, which comprise 22 resource units responsible for over 75% of annual groundwater extraction. The assessment focuses on unconfined and confined storage potential, using spatial screening methods based on stochastic iterations of spatial criteria. These criteria included factors like aquifer material extent, hydraulic conductivity, groundwater salinity, and available storage space. For unconfined aquifers, suitable areas for infiltration-based managed aquifer recharge (MAR) were identified, while confined aquifers were assessed for well injection-based MAR. The analysis utilized bore standing water level (SWL) data, groundwater salinity measurements, and potential storage volume calculations. SWL trends were analyzed from 1971 to 2021 using Sen’s Slope estimator, and salinity data were interpolated using Empirical Bayesian Kriging. For unconfined aquifers, potential infiltration volumes were estimated using groundwater level declines and specific yield (Sy), while for confined aquifers, recharge potential was calculated using the Theis solution. The modeling incorporated factors like aquifer thickness, hydraulic conductivity, and injection pressure limits to assess feasible storage and recharge potential across the resource units. Details are available in the attached metadata report.