A (In)Sustentabilidade dos sistemas de drenagem urbana: proposta de modelo de cobrança baseado em incentivo no uso de técnicas LID para financiamento dos sistemas municipais

Abstract

The unsustainability of municipal drainage systems results from the historical mismanagement of these services and can be observed with both a financial and an environmental bias. The revenue related to these systems is almost always non-existent, and when associated with the IPTU (municipal property tax) does not return to its origin, due to the other municipal priorities. In an environmental approach, the currently existing systems come from a “gray” perspective, without the perspective of nature-based solutions. In this context, the proposal of a model for the cost recovery related to the provision of urban drainage services linked to a system of incentives for the use of Low Impact Development (LIDs) practices was the goal of this dissertation, aiming at structuring a support tool in the management of the system and decision-making by the service provider. From the methodology: we opted for a Case Study, and to support it, it was necessary to carry out a bibliographic and documentary research on the forms of cost recovery adopted worldwide and on the efficiency of LID techniques, in order to enable a proposition of a system of incentives consistent with the reduction of runoff generated on the property. The stormwater fee proposed was given according to a parameter called “Equivalent Impermeable Area”, which takes into account the type of solution adopted in the property to manage the flow generated. It was realized that the proposed methodology can adapt to municipal priorities and can be a solution for promoting the use of LID practices in the municipality, which reduces the possibility of rain events generating financial and social losses, improving the quality of water bodies and the environmental conditions of the territory. For the study carried out in Itamonte, the unit value of 1m² of the “Equivalent Impermeable Area” obtained was R$ 0.15 per year and 90% of the properties would contribute with values below R$ 70.00 per year. It is concluded with this work that the remuneration for the urban drainage service can be a solution both for the cost recovery of this service and for the encouragement and foster of the use of compensatory measures in the properties, bringing sustainability to the systems.