AVALIAÇÃO DA SUSTENTABILIDADE HÍDRICA DOS RESERVATÓRIOS ESTRATÉGICOS DA SUB-BACIA DO ALTO PIRANHAS - PB

Abstract

The semi-arid region in northeastern Brazil faces drought episodes constantly. The Alto Piranhas Sub-basin, which is located in Paraíba, is inserted in this scenario, containing three strategic reservoirs: Bartolomeu I, Engenheiro Ávidos and São Gonçalo. Given this, the supply of water to important municipalities such as Cajazeiras and Sousa is being compromised, raising the need for efficient management to ensure the supply of water for current and future generations. This work aims to evaluate the water sustainability of strategic reservoirs of the Alto Piranhas Sub-basin, aiming to provide subsidies for managers in decision making regarding water allocation. The Piancó-Piranhas-Açu River Basin Water Resources Plan – PRH-PPA (ANA, 2016) was the motivation of this work, whose hydrological studies covered the period from 1962 to 2009. However, the worst drought faced by the Northeast in the last 50 years started in 2012. In order to cover it, the simulation period was extended to 2017. For the historical series of rainfall, rainfall anomalies were analyzed to identify dry and rainy years. The regularized flow rates with 100%, 99% and 90% guarantee were also defined. Five scenarios were then simulated using the AcquaNet flow network model. In some of these scenarios, the conclusion of the São Francisco River Integration Project with the Northeast Basins was considered, whose northern axis foresees a water delivery point upstream of the Engenheiro Ávidos reservoir. The simulations showed the unsustainability of Bartolomeu I from the lower demands, highlighted the importance and urgency of completing the PISF works for Engenheiro Ávidos and São Gonçalo reservoirs and drew attention to the need for efficient management in São Gonçalo, even with the PISF inflows in order to prevent its collapse. The results of this study demonstrate the usefulness of mathematical models for the simulation of reservoirs immersed in water scarcity scenarios and can guide managers in decision making in water management.