Resumo A vulnerabilidade dos recursos hídricos à curto e longo prazo está relacionada à diversos fatores como alterações no uso e cobertura da terra e mudanças climáticas. Dada a necessidade de mais informações para auxiliar na gestão da seca e no planejamento do uso da água no semiárido brasileiro, este trabalho segue duas linhas: (I) Analisar a variabilidade espaço-temporal das componentes hidroclimáticas da Bacia Hidrográfica do Submédio São Francisco; (II) Criar um índice de Vulnerabilidade Hídrica a partir da análise fatorial. Foram identificados dois fatores predominantes na bacia, solo e clima, os quais são constituídos por variáveis hidroclimaticas distribuídas espaço e temporalmente. Com o IVH, foi possível identificar as áreas que possuem o menor índice, ou seja, aquelas que são mais vulneráveis aos efeitos das mudanças climáticas, indicando que com a instabilidade no regime de chuvas deverá ocorrer menor recarga dos aquíferos, impedindo que, na época da estiagem, os reservatórios continuem a manter sua produção para o abastecimento, podendo ainda, apresentar riscos como aumento da temperatura e alterações no regime hídrico. climáticas brasileiro linhas I (I espaçotemporal temporal Francisco II (II fatorial bacia clima temporalmente IVH seja aquíferos estiagem abastecimento ainda hídrico

Abstract The vulnerability of water resources in the short and long term is related to several factors such as changes in land use and cover and climate change. Given the need for more information to assist in drought management and water use planning in the Brazilian semi-arid region, this work follows two lines: (I) To analyze the spatio-temporal variability of the hydroclimatic components of the Submédio São Francisco Watershed; (II) Create a Water Vulnerability Index from factor analysis. Two predominant factors were identified in the basin, soil and climate, which are constituted by hydroclimatic variables distributed in space and time. With the IVH, it was possible to identify the areas that have the lowest index, that is, those that are more vulnerable to the effects of climate change, indicating that with the instability in the rainfall regime, there should be less recharge of the aquifers, preventing that, at the time of the drought, the reservoirs continue to maintain their production for supply, and may also present risks such as increased temperature and changes in the water regime. change semiarid semi arid region lines I (I spatiotemporal spatio temporal Watershed II (II analysis basin IVH index regime aquifers supply

Abstract The impacts of anthropogenic degradation are becoming increasingly more evident in the Amazon and are jeopardizing its environmental systems and water resources, particularly in low monitored watersheds. Thus, the use of hydrological models is necessary to gain an understanding of these impacts on Amazonian river systems. The aim of this study was to analyze the simulation of some hydrological processes in the Itacaiúnas River watershed and its relation with human-induced impacts in the Southeast region of the Pará state using the Soil and Water Assessment Tool (SWAT) model. SWAT modeling requires several databases, such as relief, land use and land occupation, soil type, and climatic and hydrological variables. These data are input parameters for the SWAT model. The results showed that the hydrological variables in the Amazon tend to follow the seasonal precipitation cycle, with the highest values occurring between January and June and lowest between July and November. It was evident that base and lateral flows are responsible for maintaining perennial river flow during the dry season. Regarding anthropogenic actions in the watershed, precipitation, evapotranspiration, and sediment transportation are clearly affected by environmental degradation, as well as by the replacement of forest by grassland and mining activities. The results may assist in public policy including mitigation and adaptation of environmental systems in the region. In addition, they can improve the management of natural resources in the Itacaiúnas River watershed.