A Brazilian groundwater dataset for advancing integrated water surface and groundwater management

Groundwater plays a crucial role in meeting both human and ecosystem water needs. Its importance is expected to grow due to increasing water demand and the impacts of climate change on surface water resources, particularly in the Southern Hemisphere, where irrigated agricultural expansion continues to intensify. However, limitations in the spatio-temporal coverage of groundwater monitoring networks constrain our understanding of surface–groundwater interaction dynamics. Here, we present a groundwater well dataset for Brazil. It encompasses compiled and standardized well data from Geological Survey of Brazil projects. The harmonized dataset, which was validated by the Geological Survey of Brazil, underwent rigorous quality assurance and quality control procedures to ensure accuracy, adhering to principles of transparency and data integrity. The dataset includes over 351,000 wells spanning from the early 1900s to 2024, including 472 monitoring wells with daily water level measurements from 2010 to 2024. In addition to information on well location, primary use, and static water level, the dataset includes variables that can support integrated surface and groundwater management, such as distance to the nearest river, land use, and aquifer data. The potential applications of this dataset are wide-ranging. Here, we demonstrate two applications that can be replicated with other groundwater datasets. First, we compared well water levels with nearby river water levels to identify the direction of flow between Brazilian rivers and aquifers. The results indicated that over 55% of the analyzed wells in unconfined aquifers have water levels below those of the nearest river, suggesting that river water may seep into the underlying aquifer. Second, we applied the analytical depletion functions developed by Glover and Balmer to wells in unconfined aquifers to estimate streamflow depletion caused by groundwater pumping. The results suggested that approximately 9% of the analyzed rivers experience a streamflow depletion fraction exceeding 10% of their baseflow. These findings have the potential to enhance the integrated management of surface and groundwater resources in Brazil. Ultimately, we hope this accessible dataset fosters collaboration across the fields of groundwater hydrology, surface water hydrology, and water management.