Regional-scale estimates of groundwater recharge are inherently uncertain, but this uncertainty is rarely quantified. Quantifying this uncertainty provides an understanding of the limitations of the estimates, and being able to reduce the uncertainty makes the recharge estimates more useful for water resources management. This paper describes the development of a method to constrain the uncertainty in upscaled recharge estimates using a rejection sampling procedure for baseflow and remotely sensed evapotranspiration data to constrain the lower and upper end of the recharge distribution, respectively. The recharge estimates come from probabilistic chloride mass-balance estimates from 3,575 points upscaled using regression kriging with rainfall, soils and vegetation as covariates. The method is successfully demonstrated for the 570,000-km² Cambrian Limestone Aquifer in northern Australia. The method developed here is able to reduce the uncertainty in the upscaled chloride mass-balance estimates of recharge by nearly a third using data that are readily available. The difference between the 5^th and 95^th percentiles of unconstrained recharge across the aquifer was 31 mm/yr (range 5–36 mm/yr) which was reduced to 22 mm/yr for the constrained case (9–31 mm/yr). The spatial distribution of recharge was dominated by the spatial distribution of rainfall but was comparatively reduced in areas with denser vegetation or finer textured soils. Recharge was highest in the north-west in the Daly River catchment with a catchment average of 101 (61–192) mm/yr and lowest in the south-east Georgina River catchment with 6 (4–12) mm/yr.

地下水补给的区域规模估算本质上是不确定的，但是这种不确定性很少被量化。对不确定性进行量化可以理解估算的局限性，并且能够减少不确定性使补给估算对于水资源管理更加有用。本文描述了一种方法的开发，该方法使用拒绝采样程序对基流和遥感蒸散数据进行抑制，从而分别限制了补给量分布的下端和上限，从而限制了补给量估算中的不确定性。补给估算值来自氯化物质量平衡的概率估算值，使用降雨，土壤和植被作为协变量的回归克里金法，根据放大的3,575个点进行了放大。该方法已在570,000公里处成功演示²澳大利亚北部的寒武纪石灰岩含水层。在这里开发的方法能够使用易于获得的数据将补给的氯离子质量平衡估算值的不确定性降低近三分之一。5之间的差^次和95^次整个含水层的无约束补给的百分位数为31毫米/年（范围为5-36毫米/年），对于受约束的情况（9-31毫米/年）降低到22毫米/年。补给的空间分布以降雨的空间分布为主，但在植被较密或土壤质地较细的地区相对减少。达利河流域西北部的补给量最高，平均流域为101（61–192）毫米/年，东南格奥尔基纳河流域的补给量最低，为6（4–12）毫米/年。