Avaliação de condições ambientais de nascentes de cursos de água: ferramenta de subsídio à gestão de recursos hídricos e ao planejamento de bacias hidrográficas

Abstract

The protection, conservation, assessment and monitoring of natural water sources are the foundation for integrated water management and environmental planning of a watershed. Springs are important water sources, they are defined as an environmental system established by geomorphological features or geological structures, in which the outcrop of groundwater occurs in a temporary or perennial way, forming drainage channels downstream. The springs have fundamental ecological and ecosystem functions, as the maintenance of the hydrological cycle, therefore it is necessary to develop mechanisms to guarantee its conservation. The aim of this research was to investigate, identify and analyze parameters, indicators and tools related to assessment, conservation, monitoring and sustainable use of springs, in order to elaborate an integrated assessment tool for their environmental conditions that subsidize water resources management and watershed planning. For this, a Systematic Bibliographic Review (SBR) was developed to identify scientific articles and documents related to springs, showing the different approaches through which, the springs have been studied. After that, those articles and documents were analyzed to find proposals or applications of parameters, indicators, tools and instruments related to assessment, conservation, monitoring, management and/or use of springs. As a result, the list of these parameters, indicators, tools and instruments was obtained and validated by a three-step process (3S): self-validation; scientific validation and social validation. The result of this process was the elaboration of an Integrated Assessment and Monitoring Protocol for Springs (PANÁgua), which was tested through field applications and optimized according to the results of this experience and the significant contributions of the specialists who participated in the validation process. The PANÁgua is a protocol composed by three stages of application and some categories of evaluation that integrate a group of parameters and indicators related to the spring’s conservation state. Finally, this protocol was used to evaluate the environmental conditions of some springs of the Ribeirão do Tamanduá and Córrego Mineirinho watersheds located at the state of São Paulo, Brazil. Many impacts were found with the application of PANÁgua, some of them are the low density of natural vegetation coverage, as well as the erosion and silting processes because of agricultural and livestock activities that predominate in the area. In addition, the evaluation of the water quality showed the presence of total coliforms and high values of electrical conductivity in most springs. Both watersheds evaluated presents different characteristics of the land cover use, that’s why some impacts of the Córrego Mineirinho urban springs were evidenced in more critical conditions, for instance the discharge of sewage and solid waste as springs and the severe degradation of soil in general. The PANÁgua has shown to be a useful and efficient tool that synthesizes and assess the environmental conditions of the springs in a coherent way and can be used to help the environmental agencies in the decision-making processes related to integrated water resource management and watershed environmental planning.