In southwestern Bangladesh, clean drinking water is scarce, since rainwater is only available during the monsoon, pond water is often bacteriologically polluted, and groundwater may exhibit high salinity and arsenic levels. Managed aquifer recharge (MAR) might potentially provide safe drinking water by storing abundant freshwater from the wet season in aquifers for year-round use. Regional potential for MAR was determined by combining assessments of (1) social necessity for MAR by mapping areas with insufficient drinking water of acceptable quality; (2) regional technical suitability by determining the (a) impact of density-driven flow on freshwater recovery efficiency, and (b) vulnerability of recovered water to mixing with contaminated groundwater. These assessments were based on the largest groundwater quality dataset compiled to date in southwestern Bangladesh, which contains 3,716 salinity and 827 arsenic measurements. The results show there is some mismatch between social necessity and technical suitability. In some northern areas, necessity is low because good quality groundwater is present and hence, despite the high technical suitability, potential for MAR is reduced. In other northern areas, groundwater with unsafe arsenic levels or brackish groundwater is likely used for drinking. There, MAR is a technically suitable and safer option. In southern areas, where saline groundwater is widespread and people consume bacterially unsafe pond water, the high groundwater salinity calls for careful evaluation of MAR design, for which this study presents practical guidelines. The approach developed may be useful for mapping MAR potential based on social necessity and technical suitability in other saline deltas worldwide.

在孟加拉国西南部，清洁的饮用水很少，因为雨水仅在季风期间提供，池塘的水经常被细菌污染，并且地下水可能显示出高盐度和砷含量。有管理的含水层补给（MAR）通过将潮湿季节的大量淡水储存在含水层中以便全年使用，可能潜在地提供安全的饮用水。通过结合以下方面的评估来确定MAR的区域潜力：（1）通过绘制饮用水质量可接受的不足区域来绘制MAR的社会需求；（2）通过确定（a）密度驱动的流量对淡水回收效率的影响，以及（b）回收水与受污染的地下水混合的脆弱性来确定区域技术适用性。这些评估基于迄今为止孟加拉国西南部最大的地下水水质数据集，其中包含3,716个盐度和827个砷测量值。结果表明，社会必要性和技术适用性之间存在一些不匹配。在北部一些地区，由于存在高质量的地下水，因此需求较低，因此尽管技术适用性很高，但MAR的潜力却降低了。在其他北部地区，可能会使用砷含量不安全的地下水或微咸的地下水来饮用。在那里，MAR是一种技术上合适且更安全的选择。在南部地区，地下水含盐量很高，人们消耗了细菌不安全的池塘水，因此，较高的地下水盐度要求对MAR设计进行仔细评估，本研究为此提供了实用指导。