This study aimed to propose a methodology for charging for the use of water resources based on the allocation of costs - among sectors that demand water - of projects related to improvements in a river basin. This methodology consists of a rule of allocation known as Shapley value, belonging to the theory of cooperative games, and to show its applicability, we performed a case study in a sub-basin of the Paraíba do Sul river basin. As criteria for allocation of costs, we used the volumes of water withdrawn and consumed, and the amount of effluent discharged into the river. In applying the methodology, we considered three different scenarios: "clean" basin, polluted basin, and an intermediate situation, closer to real situation now found in the sub-basin analyzed. The obtained results showed high dependence of the cost allocation criteria (weights assigned to the volumes of water withdrawn and consumed, and the quantity of effluent discharged), and, in the case of intermediate scenario considered, the values found indicate that the urban users should pay the greatest part of the costs when compared to the fees currently in use, since these users are among those that greatly discharge effluents, being the deterioration of water quality the most relevant problem in this basin.
water resources; cost allocation; Shapley value; river basin
