In-situ hydrological monitoring is essential for a proper decision-making process and modelling. Efforts have been made in Brazil to carry out field activities at the basin scale, but how complete and comprehensive are those studies? Where are they located? How long have they been carried out? What are the main findings? To answer these questions, an overview of experimental monitoring basins in Brazil is presented, listing their geographical locations, monitored variables, operational status, monitoring periods and main publications. We identified 60 monitored sites, spread across most Brazilian biomes, with an average monitoring period of 12 years. However, some publications from these monitoring studies are not fully accessible to the international community. Field hydrology activities in Brazil contribute to a better understanding of hydrological processes in humid and semi-arid regions and inform us about the impacts of land-use change on water quality and quantity.

This paper aims to evaluate the characteristics of rainfall events of three experimental basins located in northeast Brazil. The study areas are located, one in Ceará State and two in Paraíba State. Thus, the definition of rainfall events was based on two characteristics: minimum inter-event time and minimum event depth. Then, they were classified according to the shape of the hyetograph: to the left rectangular, triangular, and triangular with peak, and to the right, bimodal and unshaped. Evaluation of the percentages of each type of hyetograph and the main characteristics of rainfall events (peak, duration and intensity) was carried out. The results shows that the two experimental basins located in the semi-arid region have similar characteristics, and shapeless events have significant accumulated rainfall.

Global assessments have exposed considerable inconsistencies among precipitation datasets, particularly over regions with complex terrain or sparse observation networks. These uncertainties are especially critical in Brazil, where climatic diversity, topographic complexity, and uneven gauge distribution make reliable rainfall monitoring challenging. This study conducts a comprehensive evaluation of rainfall trends and distributional similarity across Brazil using five long‐term gridded datasets—gauge‐based (BR‐DWGD), satellite‐gauge blends (CHIRPS and PERSIANN‐CDR), and reanalysis products (ERA5‐Land and MERRA‐2)—and for four precipitation indices: PRCPTOT, R20, R99PTOT, and TDD. We assess the similarity between the gauge‐based BR‐DWGD and the other four gridded precipitation products using normalised Mann–Whitney U statistics. Regarding temporal distribution, CHIRPS shows the highest agreement with BR‐DWGD ( U = 1.00 for PRCPTOT, R99PTOT and TDD), while ERA5‐Land performs better for R20 ( U = 0.59) but shows moderate to low agreement for other indices ( U = 0.25–0.47). PERSIANN‐CDR and MERRA‐2 exhibit poor similarity, with U values generally below 0.12 and close to zero, respectively. However, trend detection using the Mann–Kendall test with Trend‐Free Pre‐Whitening and False Discovery Rate correction reveals substantial regional disparities, with MERRA‐2 and ERA5‐Land partially replicating BR‐DWGD's drying trends for total precipitation ( U = 0.83 and U = 0.69, respectively), but identifying more extensive significant trends, especially in Southeast and Northern Brazil. Conversely, CHIRPS and PERSIANN‐CDR detect few significant trends. Factors such as gauge density and satellite‐based corrections influence dataset performance. Despite limitations, annual trends offer valuable insights into precipitation alterations over the past four decades in Brazil, with implications for climate change impacts and regional hydrological cycles. However, the significance of trends varies spatially, underscoring the need for careful dataset selection in regional climatological studies and highlighting the persistent challenges of representing rainfall trends in tropical and subtropical climates using global gridded products.

Managed Aquifer Recharge (MAR) is a useful tool for the treatment and use of sewage effluent because it complements conventional treatment, recovers the aquifer and minimizes risk of saltwater intrusion. This study aims to investigate technical data to determine the treatment of wastewater stabilization pond effluent using undisturbed soil columns collected from a coastal watershed study area within the BRAMAR (BRAzil Managed Aquifer Recharge) project. The treatment efficiency was monitored by measuring physico-chemical parameters (BOD ₅, COD, DOC, TSS, NH₃ and NO₃) in two columns filled with undisturbed sandy soil in which sewage effluent was infiltrated under unsaturated condition for 72 days with an average input flow of 10 mm h^-1. Results indicated reduction greater than 60% of organic matter, suspended solids and ammoniacal nitrogen. However, high concentrations of nitrate in the outflow were detected originating from nitrification of ammoniacal nitrogen. Moreover, difficulties in relation to soil clogging were observed. Furthermore, this study brought relevant contributions to understanding the influence of the infiltration rate and ability to treat effluent from wastewater stabilization ponds using undisturbed soil columns. Future research should be undertaken to improve the pretreatment methods and the operation of a MAR system in the study area.