Diagnóstico da disponibilidade hídrica superficial da bacia hidrográfica rio Capim - BHRC: como ferramenta de suporte à decisão para outorga de recursos hídricos

Abstract

The dissertation addresses the need to monitor the quantitative water balance in the Rio Capim Watershed (BHRC), Pará, Brazil, due to the variability of precipitation throughout the year and water scarcity in some areas during dry periods. The general objective is to determine the water availability of BHRC based on the regularization of water users (issued and active water permits) as a subsidy for water resource management efficiency. To achieve this objective, the study was conducted in five stages: literature review, data collection of granted water interferences, organization of vector data for ottobasins and surface water availability from the Ottocodified Hydrographic Database of Pará (BHO/PA), data processing, and quantitative water balance assessment. Results revealed that certain municipalities have significantly more granted water permits than others, such as Paragominas (29.5%), Dom Eliseu (25%), and Ipixuna do Pará (17.5%), totaling 72% of all issued permits. Surface water in BHRC is utilized for various purposes, with irrigation being predominant, accounting for 79% of the total captured volume. Other significant uses include mineral extraction and industrial purposes, totaling 18% of the captured volume. It was identified that 180 ottobasins are directly impacted by granted water withdrawals, while 3,081 ottobasins are indirectly impacted downstream, totaling 3,181 impacted ottobasins throughout the watershed. The Surubiju River and its tributaries show the highest impact, with 89 directly impacted segments and a withdrawal flow of 206,355.73 cubic meters per day. These findings underscore the need for continuous and detailed monitoring to ensure water resource sustainability in BHRC and serve as a critical tool for decision-making in water resource allocation in Pará State.