DECISION SUPPORT IN WATERSHED MANAGEMENT: EVALUATION AND MAPPING OF WATER QUALITY FOR POTABILITY

The increasing pressure on water resources demands robust methods for assessing water quality and prioritizing sanitation actions. This work aims to establish a ranking of criticality of the hydrographic basins of the State of Rio de Janeiro regarding the quality of the raw water collected, based on physicochemical and microbiological indicators. For this, a hybrid multicriteria model is applied, combining the MEREC method, for objective determination of the weights of the criteria, and the CoCoSo method, for the final ranking of the basins. Historical data from 325 monitoring stations (2012–2023) from ANA, INEA, and CEDAE were used, aggregated by basin and treated for missing values. The results show basins with improved water quality, such as Guandu, and others with persistent degradation, such as the Baixada Fluminense, in addition to identifying benchmark basins to support public policies for sanitation and water recovery.