Análise dos impactos gerados no sistema de abastecimento de água, devido à evacuação de moradores, em área afetada pela subsidência do solo na cidade de Maceió/AL

Abstract

Due to their configuration and extension, water supply systems (WSS) are susceptible to suffer important technical problems and also be affected by unpredictable environmental conditions, such as disasters. In view of the public emergency situation experienced in the city of Maceió, this paper aims to evaluate the impact of residential eviction due to terrain instability in neighborhoods of Maceió, in the water supply system of the affected region, aiming at the proposition of strategies to reduce the implications generated. The study area and its supply system were characterized, the network registration and insertion of parameters were performed through the QGIS software and the model was exported to the EPANET software for the execution of the hydraulic simulation and calibration of two scenarios, prior to the event and current. Finally, the strategy that could be beneficial to the WSS was identified and a new simulation was performed to verify the pressure. With the eviction of the houses in the neighborhoods of the affected region, there was a reduction of 41.30% in the number of active water connections, 44.45% in water consumption and 31.72% in billing, representing a loss of more than 500 thousand Reais per month. Through the hydraulic simulation, it was observed that 55.46% of the network presented an increase in pressure between 0 and 5 mca, and 15.14% an increase greater than 10 mca, at the time of highest consumption, which could cause leaks in the pipes. The pressure drop values decreased due to the reduction in friction of the liquid with the walls of the conduits, caused by the variation in consumption throughout the day. The strategy used for the OSS was to cap the entire distribution network, keeping only the main water mains that supply water to other areas. The simulation of this scenario showed that the pressures obtained are sufficient for supply, with a variation between 0 and 1 mca in 87.34% of the nodes in relation to the current scenario. Thus, the proposed strategy to minimize the impacts generated in the WSS proved to be effective.