Planejamento da segurança hídrica em cenário de mudança climática considerando avaliação de custos de múltiplos mananciais

Abstract

Prolonged and severe droughts in various regions of the world show the need to consider water security. The present work aims to propose a methodology for water security planning in a scenario of climate change, considering cost evaluation of multiple water bodies. The methodology was applied to the Jaguaribe-Metropolitan Water Supply System, located in state of Ceará. Then, 26 possible scenarios were framed, incorporating increased demand (population growth, loss reduction) and improved supply (transposition, desalination, industrial reuse, reuse within the lot, construction of cisterns, and well drilling), as well as the cost assessment of each of those alternatives separately. In order to evaluate those scenarios, discharges from a reconstructed series for the period 1911-2017 were used, as well as predicted discharges for the period 2015-2050, generated using precipitation and temperature data from the following CMIP6 global models: BCCCSM2- MR, CanESM5, IPSL-CM6A-LR, MIROC6, and MRI-ESM2-0. The discharges were obtained by coupling the monthly SMAP model. Results showed that the merging of waters from the transposition of São Francisco River will not be enough to avoid failure in the water supply system, that is, water supply alternatives must be sought, and the cost evaluation tool plays a major role in it. Moreover, it was observed that the driest models (BCC-CSM2-MR, CanESM5) presented failure values close to or smaller than those in the reconstructed series. This was due to the fact (observed through correlograms) that the duration and frequency of droughts in these models are shorter than in the reconstructed discharge series