Influência da transferência de água entre bacias hidrográficas na operação de sistemas hídricos em regiões semiáridas

Abstract

Water scarcity is a recurrent problem in semi-arid regions, mainly due to the low incidence of precipitation and high evapotranspiration, which result in reduced water availability and low reliability for the supply of water demands. From this perspective, water transfer projects between river basins are an important solution to ensure access to water for the populations of these regions. The present study has as its general objective the definition of a methodology for the operation of water systems in hydrographic basins in semi-arid regions, in the context of water transfer between basins, in order to achieve greater assurance in meeting the demands for water. For this, two specific objectives were defined: (i) define the hydrological status of the reservoirs that are part of the water system and that trigger the need for water transfer and; (ii) optimize the transferred volumes that result in the greatest synergic gain in the use of water resources in the system. In order to meet these objectives, four scenarios were simulated, where the hydrological states of the reservoirs that are part of the hydrographic system of the ApodiMossoró river hydrographic basin (BHAM) were defined, in order to know the capacity of regularization of these reservoirs, considering the entry or not of the exogenous flow of the São Francisco River Integration Project with the Northern Northeast Basins (PISF), in addition to optimizing the volumes transferred by it, considering the hydrological status of the two main reservoirs of this basin, the dams of Pau dos Ferros and of Santa Cruz do Apodi. The results obtained demonstrated the current situation of this system, where it was possible to identify deficits in meeting the demands of the reservoirs, especially for the Santa Cruz dam. Through the analysis of the regularized flow of the reservoirs with the constant transfer of water, it was observed that this has an increase proportional to the transferred volume, enhancing the efficiency for the different uses in the basin, in addition to the reduction of losses in the main reservoirs, the dams of Pau dos Ferros and of Santa Cruz. In addition, the optimization of the transfer of water from the PISF, based on the hydrological status of the reservoirs under study, allows the reduction of the total volume to be requested by the State to meet its demands, reducing the costs of transferring water. Therefore, the application of adequate policies and rules for the operation of reservoirs plays a fundamental role in the management of water resources in this region, being essential for planning and aiding in decision-making on when and how much to transfer water.