Estresse hidrológico: aplicação às bacias dos rios Paraopeba e Sapucaí, Minas Gerais

Abstract

O cotejo entre as demandas e as disponibilidades hídricas, em meio às diversas variáveis a serem consideradas na atividade de gerenciamento, apresenta diferentes cenários, cujas avaliações e interpretações são muito úteis às tomadas de decisão pelo órgão gestor de recursos hídricos. Uma das possíveis alternativas para se realizar tal cotejo refere-se ao conceito de estresse hidrológico, o qual estabelece o balanço entre a vazão disponível, obtida com base na curva de permanência de vazões de uma dada seção fluvial,e a soma das demandas. O princípio é definir um valor limiar para a proporção entre o valor de pico do conjunto das vazões de demanda e um dado percentil da curva de permanência, acima do qual se estabelece uma situação de estresse hidrológico. Assim, objetivou-se neste trabalho, empregar este conceito, por meio de um estudo de caso envolvendo as bacias dos rios Paraopeba e Sapucaí, avaliando o nível de estresse distribuído por sub-bacia. Os resultados referentes aos índices de estresse hidrológico no qual as bacias se encontram situam-se em níveis desde baixo a alto, apontando para a necessidade de alterações na política de gestão de recursos hídricos no Estado de Minas Gerais.

Determination of hydrological stress in a river basin in northeastern Brazil

“…According to Durães et al (2015), this methodology takes into account the analysis of the permanence curve, which reflects seasonality, physiographic characteristics of the sub-basins, location, and geology. It therefore provides management bodies with a hydrological stress assessment tool.…”

“…The efficient allocation of water among the usage demands required by the various economic sectors, as well as the maintenance of necessary minimum flows in the watercourses to protection the river ecosystems are tasks frequently required of water resource managers and governmental agencies (Durães et al, 2015). According to Harris et al (2006), hydrological stress (HS) is an index that determines the amount of discharge reduced from a watercourse due to concessions to meet the various water usage demands.…”

“…|It is necessary to assess the degree of commitment of rivers, using indices that describe the current and future situation of water resources. The creation of limits and criteria for framing water bodies, similar to those for quality, which are based on availability and demand, improves water allocation among the various uses and users, according to Durães et al (2015).…”

“…A methodology adopted by the Department of Natural Resources of New South Wales (2006), called Macro Water Sharing Plans (MWSP), determines the degree of hydrological stress (HS) on a basin or sub-basin, based on the climatic vulnerability and use of water resources in the basin. This methodology was also applied in Brazil by Galvão (2008) and Durães et al (2015). Durães et al (2015) pointed out that determining hydrological stress provides water resources management agencies with a tool that assists in decision-making with regard to future permits to be granted, in the assessment of the impact of current demands, and in rational water management.…”

“…This methodology was also applied in Brazil by Galvão (2008) and Durães et al (2015). Durães et al (2015) pointed out that determining hydrological stress provides water resources management agencies with a tool that assists in decision-making with regard to future permits to be granted, in the assessment of the impact of current demands, and in rational water management. The same authors studied the hydrological stress in Minas Gerais, considering a reference flow determined from the entire series of available flow data as a discharge corresponding to 90% of permanence (Q90).…”