Modelo de cobrança pelo uso dos recursos hídricos em sistemas controlados por reservatórios.

Abstract

Despite the fact that more than four decades have passed since the actual start of discussions on sustainable development, many countries still face serious problems related to the environment and especially to water resources. In fact, the growing process of environmental degradation, as well as the guidelines established by Law 9.433/97, has established mandatory and driven the creation of systems of law grant and charging for the use of water resources, aiming at a greater efficiency in the use of resources water resources in Brazil. The charging for the use, while one of the management tools of the National Water Resources Policy (PNRH), has become one of the main mechanisms used by the federative states to manage their water resources. In this sense, the goal of this research was to develop a charging model for the water resources use capable of inducing a more rational water use through greater objectivity, completeness, parsimony and transparency of the processes involved in water resource systems controlled by reservoirs. In Brazil, water management has your legal and institutional apparatus, as main regulatory element, supported by the Law 9,433/97, which is the basis of the PNRH of the National System of Water Resources Management (SNGRH). According to the Law 9,433/97, water resources that were submitted to the granting process will be charged, in accordance with the established guidelines. In this sense, based on the existing models, progress has been made in the implementation of new processes in a water charging model for the use of surface water resources in systems controlled by reservoirs. Among the characteristics intended and incorporated into the model, it’s worth to point out the interrelation between water resources granting and charging with the scope of the rational water use induction. In addition, was included other possible and operationally viable aspects that may exist in any water resources system controlled by reservoirs. The way it was designed allows its perfect adequacy, implementation and operation, especially in the brazilian semi-arid region watersheds. As a case study, the region made up of the Planning Unit of the Alto Piranhas (UPHAP), in the Piancó-Piranhas-Açu/PB river basin, which includes two interdependent reservoirs (Engenheiro Ávidos and São Gonçalo), was used. This characteristic was of fundamental importance for the construction and validation of the water use charging model linked to the amount of water flow allowed by the granted water resources use right. From the obtained data, , it was analyzed, integrated through an optimization model, the flows provided by the system to attend the water use licenses, the ix volume of reservoirs, as well as the flows in the stretch of the river between the two reservoirs. Four system operation optimizations were performed assuming two possible scenarios: involving or not the transposition of the São Francisco River. For each of these two scenarios, two distinct situations were considered: water demands with or without flow measurement. The test demonstrated: 1. The values charged by the cubic meter of water are compatible with local and national reality; 2. Possibility of encourage, through the model, the rational use of water, inhibiting the inefficient uses of water, practice of reservation of water, through grants, and potential extra abstractions of water by users; 3. The ability to adapt the model to various realities and scenarios, especially in the semi-arid region; 4. The proposed water charging model can be applied in any watershed, being possible to resize the used parameter values via a more participatory and democratic process within the river basin Committee; and 5. The parsimony and efficiency of the model.