Proposta de um índice para avaliação de desempenho de sistemas de drenagem de águas pluviais em cidades de pequeno porte do Estado da Paraíba.

Abstract

The changes suffered by the drainage basins during the urbanization process of the municipalities result in the recurrence of extreme events that directly impact the population. In small municipalities the situation is aggravated by the lack of planning, inexperience of the authorities and by inexistent conventional rainwater drainage systems. Evaluating and monitoring the performance of the service makes it possible to identify critical areas and their greatest difficulties. The creation of performance indexes has become a frequent practice for this purpose, mainly in the area of Environmental Sanitation. Under this context, the present study aimed to develop a performance index for the rainwater drainage service, adapted to the limitations of small municipalities in Paraíba through the aggregation of indicators that summarize the main aspects related to the systems, such as: existing infrastructure; maintenance; urbanization; health; risk management; and legislation. The indicators were selected through the proposition of other published works and consolidated and reliable databases. The composition of the index was based on seven methodological steps: selection of indicators; definition and characterization of case studies; consultation with experts and validation of indicators; determination of classification categories; application of the Multicriteria Analytic Hierarchy Process (AHP) method; sensitivity analysis and results analysis. The municipalities of Areia, Cabaceiras, Natuba, Nova Olinda, São Bento, São José de Piranhas, São José dos Ramos and Serra Grande were selected as case studies. The consultation with specialists indicated a greater importance attributed to the indicators of risk management, existing system and urbanization. It was possible to verify the precarious infrastructure and risk management policies as the main problems faced by municipalities in Paraíba. The index proved to be robust in assessing the performance of drainage systems and consistent with reality, but was considered more sensitive when comparing municipalities. Among the case studies, Serra Grande obtained the best and Natuba the worst performance. It is expected that this work will contribute to the management of the urban rainwater drainage service by directing public policies and investments that reduce the population's vulnerability and accelerate the decision-making process.