Nova proposta para o processo de outorga em sistemas de reservatórios - estudo de caso: bacia hidrográfica do Rio Piancó.

Abstract

Water rights instruments are quite important for management of water resources, as it assures the qualitative and quantitative control of water uses, as well as the users accesses to water. The water rights, in Brazil, are ruled by Law 9.433/97, specific state laws and decrees. At Paraíba state, for example, the water rights are ruled by Law 6.308/96, which has been regulated by Decree 19.260/97. Although there is a number of regulations, this instrument is still difficult to implement and administrate. For the Piancó river basin, located at sertão (inland) Paraibano and having the greatest water reservation capacity of the state, the water rights process is more complex due the existing conflicts on water use. Moreover, this basin has most of its water controlled by reservoirs and methodologies for calculating the water rights maximum stream flows seems not to be adequate for determining it. Therefore, this work is concerned with the development of a linear optimization model to couple with this kind of problem, as it deals with the possibility of water rights concession or not through the use of reservoirs sub-basins concepts, as well as it may be able to couple with monthly variable flows concession requests, which seems to be more adequate to the water uses within this basin. The application of this model to Piancó river basin has generated coherent results and may be applied to other basins controlled by reservoirs. The study has also shown that approximately 30% of Coremas-Mãe D Água upstream reservoirs are not able to couple with the demands of water rights concession as they cannot fulfill the requirement of 90% for reliability as ruled by State Decree 19.260. Althouth the Coremas-Mãe D Água reservoir system has the greatest water reservation capacity of the state, one must be careful about water rights concession grants, once the system presents water deficit, which compromises the fulfillment of its already granted water rights concessions. Therefore, a more rigorously reevaluation of its already granted water rights concessions, as well of the new ones, should be performed for the Coremas-Mãe D Água reservoir system and upstream reservoirs.