Integração de modelos de outorga, cobrança e análise multicriterial e miltidecisor: uma aplicação na bacia do Rio Paraiba - PB.

Abstract

The answer to growing demands for water for multiple purposes, involving conflicts among users, is one of the major challenges to be solved in the management of water resources, considering that water has different importance for each user, which assigns different priorities for each of its uses. One of the highlights within these challenges is the need to promote advances in the use of water allocation mechanisms, with the integration of water resources management instruments such as: water rights grants and charging mechanisms associated with a multi-criteria and multi-decision maker analysis in order to address the basin water availability to is economic, social and environmental uses. In this context, this study aimed to integrate the water right grant and charging instruments to promote water allocation under a multicriteria analysis view. The priorities to the user’s water right volumes allocation were attained via a multicriteria and multi-decision maker approach and a water right optimization model. The water charging model takes into account the granted water rights volumes as well as technical, economic, social and environmental aspects of the water resources system. The area defined for the research development is the watershed of the Rio Paraiba-PB, which is inserted in the semiarid region of the Brazilian Northeast region. The selected reservoirs for the application of the methodology were Poções, Camalaú, Cordeiro, Epitácio Pessoa and Acauã. The ranking of water uses for granting water rights were attained from the application of the multicriteria Promethee analysis where the weights, representing preferences, were assigned by multi-decision makers, which participate in this research. The water right grant model utilized was adequate for the purpose of optimizing the guarantee of the variable water grants demands according to the users priority order, by adapting the water availability to its demands. The proposed charging model allows one to vary the amount of charged price of the granted water volumes, by incorporating coefficients representing different user profiles: if they make water reserves, use more efficient water systems and treat their effluent. The water rights grant model showed that it can be used to evaluate the possibility of insertion of new water users, as well as to evaluate situations when are added the contribution of flows of the PISF's east axis. The proposed water charging model can be seen as an instrument that play a role to encourage the rational water use, to reduce losses in supply systems, to improve the wastewater treatment and discourage water reservations, among other aspects, besides being a tax collection instrument.