Emprego de geoprocessamento para identificação de mananciais com disponibilidade hídrica estudo de caso: abastecimento urbano da cidade de Itabira-MG

Abstract

The city of Itabira-MG, like many Brazilian cities, faces serious problems of water scarcity in its public supply system. This work seeks, through the use of geoprocessing and water quality assessment, to identify and propose new water sources that have sufficient flow to meet the demand and present water quality standards that fit to the current treatment system adopted by the city. In the present study, two methodologies for regionalization of minimum flows were used to identify the water streams with sufficient flow to support a unitary collection capable of meeting the projected demand of the city by the year 2047. Subsequently, sampling points were selected in these water courses where measurements of water quality parameters were performed to calculate the WQI and land use and occupation maps were drawn up for each drainage basins for these points. Thus, it was analyzed the correlation between the characteristics of the drainage basins with the values of the Water Quality Index (WQI) and with the concentrations of the parameters that compose it at each point. From the evaluation of the concentrations of the analyzed parameters, it was possible to conclude that the water at the analyzed points may be used for public supply after conventional treatment, considering that control measures must be applied to minimize the contamination by faecal material and also to reduce the turbidity. Through the land use and occupation maps it was possible to identify the regions that need interventions and may represent dangers for water quality at the studied streams, and the efficiency of its use would be increased if these maps were elaborated on a smaller scale and with a greater number of incursions in field to identify the pollution points. With the aid of GIS, the flow rates Q7,10 were calculated for all water courses in the basins under study and, based on the study of the water availability of the area, it was identified that the potential for conflict over the use of water resources is relatively low. Finally, considering the flow available for abstraction, the land use and occupation and the quality of the water found in the basins, it is recommended as the best place for the implementation of a unitary abstraction capable of serving the city of Itabira-MG the Tanque River, somewhere between the analyzed points. And we do not recommend a new abstraction point neither in the Santa Bárbara river, nor in the Jirau stream nor in the Peixe river.