Metodologia para identificação de áreas críticas quanto à disponibilidade hídrica superficial no estado do Paraná

Abstract

The escalating demand for water, inadequate planning, climate change, and insufficient investments in water infrastructure have significantly impacted various sectors and users, giving rise to water crises and consequent conflicts over water utilization. In Brazil, numerous regions, including the state of Paraná, bear witness to issues pertaining to water unavailability for extraction and effluent dilution, necessitating the identification of critical hydrographic regions. Nevertheless, at present, a consensus is lacking between the National Water and Basic Sanitation Agency and the respective state entities responsible for water resource management regarding the criteria that categorize hydrographic basins as critical. Consequently, procedures, terminologies, concepts, and tools employed vary across institutions nationwide. The principal objective of the methodological approach adopted in this research is to devise a methodology for ascertaining hydrographic areas afflicted by compromised surface water availability, specifically within the framework of the water rights granting instrument applicable to the state of Paraná. Guided by the stipulations outlined in Resolution CERH nº. 09/2020, this methodology hinges upon defining the parameters for surface water extraction and effluent discharge rights, and encompasses four distinct stages: delineation of the coverage area, identification of water resource uses, assessment of water availability, and classification based on the degree of criticality. To evaluate the feasibility and efficacy of the proposed approach, the hydrographic sub­basins of the Toledo River and Quatro Pontes Stream, situated in the western region of Paraná, were selected as case studies. The findings indicate that both hydrographic areas exhibit degrees of criticality ranging from 5 to 6, signifying complete water compromise and absence of water availability, with 96.7% and 119.1% of the maximum permissible flow compromised, respectively. The formulation of this methodology holds the potential to expedite the identification of compromised hydrographic areas, enabling the establishment of criticality levels based on the interplay between water demand and availability. Additionally, it may serve as a valuable methodology to inform and prioritize decision­making processes within the domain of water resource management, benefiting the executive governing body responsible for water resources, the Water and Land Institute, as well as relevant governing bodies within the system.