Fifty-four water samples were collected between July and December 2019 at nine monitoring stations and fifteen parameters were analysed to provide an updated diagnosis of the Piabanha River water quality. Further, forty years of monitoring were analysed, including government data and previous research projects. A georeferenced database was also built containing water management data. The Water Quality Index from the National Sanitation Foundation (WQINSF) was calculated using two datasets and showed an improvement in overall water quality, despite still presenting systematic violations to Brazilian standards. Principal components analysis (PCA) showed the most contributing parameters to water quality and enabled its association with the main pollution sources identified in the geodatabase. PCA showed that sewage discharge is still the main pollution source. The cluster analysis (CA) made possible to recommend the monitoring network optimization, thereby enabling the expansion of the monitoring to other rivers. Finally, the diagnosis provided by this research establishes the first step towards the Framing of water resources according to their intended uses, as established by the Brazilian National Water Resources Policy.

RESUMO No Brasil, mais de 80% da população brasileira vive em cidades. Como consequência desse crescimento populacional, há impermeabilização do solo, ocupação das faixas marginais de proteção dos rios, desmatamentos, canalização de rios, quantidade crescente de resíduos sólidos que são jogados nesses corpos hídricos, dentre outras. Quando ocorre grande precipitação pluvial, os corpos hídricos transbordam provocando inundações com danos materiais, humanos, ambientais que impactam a saúde da população. No mundo, 20 milhões de pessoas sofrem anualmente com enchentes. O Brasil ocupa a 11ª colocação no ranking com 270 mil pessoas atingidas pelas inundações. Este artigo, pesquisa histórica, descritiva com pesquisa bibliográfica e documental, faz uma reflexão da evolução do processo de manejo de águas pluviais urbanas desde a fase da drenagem tradicional, com a implantação de medidas estruturais e não estruturais com o propósito de afastar as águas, passando pela drenagem sustentável, quando, com intuito de retardar o fluxo das águas são construídos reservatórios subterrâneos até a fase atual quando são propostas soluções baseadas ou em sintonia com a natureza, com estruturas cinzas e verdes. Deseja-se contribuir para a sensibilização de gestores e da população para que cada um cumpra o seu papel no consciente manejo adequado das águas pluviais urbanas.

The Framing of Water Bodies in Preponderant Uses Classes, according to Conama Resolution nº 357/2005, enables the establishment of goals to be achieved, or maintained, in a body of water according to its predominant uses. Its proposal is the responsibility of the River Basin Committees, in the Mountain Region of the state of Rio de Janeiro; The Piabanha Committee has set the Framing of the Piabanha River as a priority. In this sense, the objective of this article was to compare the extent to which the Framing behaves as a process of rehabilitation of river health. It seeks to build a theoretical approach and define methodological guidelines for water resources framing projects. In the conclusions, five recommendations that are considered key to the framing process are emphasized. KEYWORDSWater use. River pollution. Water quality. RESUMO O Enquadramento dos Corpos Hídricos em Classes de Usos Preponderantes, de acordo com a Resolução Conama nº 357/2005, possibilita o estabelecimento de metas a serem alcançadas, ou mantidas, em um segmento de corpo d'água de acordo com seus usos preponderantes. Sua proposição é responsabilidade dos Comitês de Bacia Hidrográfica, na Região Serrana do estado do Rio de Janeiro; o Comitê Piabanha definiu como prioridade o Enquadramento do Rio Piabanha. Nesse sentido, o objetivo deste artigo foi comparar em que medida o Enquadramento comporta-se como um processo de reabilitação da saúde dos rios. Busca-se construir um referencial teórico e definir diretrizes metodológicas para projetos de enquadramento de recursos hídricos. Nas conclusões, são destacadas cinco recomendações consideradas chave para o processo de enquadramento. PALAVRAS-CHAVE Usos da água. Poluição de rios. Qualidade da água.

Water quality has been a global concern, as evidenced by UN Sustainable Development Goals. The current paper has focused on the Piabanha River rehabilitation as a case study which can be generalized to other similar watersheds. A monitoring program during a hydrological year was carried out, and different databases were used to calibrate and validate the QUAL-UFMG water quality model. Sanitation is the major problem in the watershed, notably in its headwater catchments, which concentrate the most urbanized regions where water quality is worse in the dry season due to low river flows. Thus, simulations of the river water quality have been performed through computational modeling suggesting organic load reductions in some sub-basins. In conclusion, some strategies to improve water quality have been discussed: (i) The water quality rehabilitation must consider progressive goals of pollution reduction starting with an initial implementation in a reduced area. The monitoring should be based on a few parameters relevant and simple to monitor. (ii) Pollution reduction ought to be carried out strategically with deadlines and intermediate goals that must be agreed upon between the stakeholders in the watershed. (iii) Watershed committees should supervise projects to improve water quality in partnership with the State Prosecutor’s Office.