Constraining probabilistic chloride mass-balance recharge estimates using baseflow and remotely sensed evapotranspiration: the Cambrian Limestone Aquifer in northern Australia

Abstract Regional-scale estimates of groundwater recharge are inherently uncertain, but this uncertainty is rarely quantified. Quantifying provides an understanding the limitations estimates, and being able to reduce makes more useful for water resources management. This paper describes development a method constrain in upscaled using rejection sampling procedure baseflow remotely sensed evapotranspiration data lower upper end distribution, respectively. The come from probabilistic chloride mass-balance 3,575 points regression kriging with rainfall, soils vegetation as covariates. successfully demonstrated 570,000-km 2 Cambrian Limestone Aquifer northern Australia. developed here by nearly third that readily available. difference between 5 th 95 percentiles unconstrained across aquifer was 31 mm/yr (range 5–36 mm/yr) which reduced 22 constrained case (9–31 mm/yr). spatial distribution dominated rainfall comparatively areas denser or finer textured soils. Recharge highest north-west Daly River catchment average 101 (61–192) lowest south-east Georgina 6 (4–12) mm/yr.