Groundwater provides a critical buffer for urban water security, yet contamination by nitrate from deteriorating sewer networks poses a persistent and globally underestimated threat. Unlike agricultural pollution, urban-derived nitrate is sustained by diffuse, chronic leakage from buried infrastructure, producing plumes that can persist for decades. Here, coupled groundwater flow and solute transport models (MODFLOW–MT3D) were...

Following recent prolonged regional droughts, reliance on groundwater resources in São Paulo State, Brazil, has increased, emphasizing the need for robust evaluations of groundwater availability to support integrated water resources management. For this purpose, dependable methods for estimating groundwater recharge were applied. This paper focuses on one of the region’s most important aquifers, the Bauru Aquifer System (BAS),...