Water quality index in two land use situations in the Mantiqueira Range

Abstract

The use of a large number of water quality indicators increases the costs of streamflow monitoring throughout the time. Principal Component Analysis (PCA) can be considered a promised tool for water resources management, allowing a reduction in the dimensionality of the data and facilitating their analyses. This study aimed to obtain a water quality index (WQI) to characterize the Mantiqueira Range region. Water quality indicators from a sub-basin entirely occupied by Atlantic Forest and from another predominantly occupied by pasture were normalized and used to compose the WQI. The normalized values were submitted to a PCA evaluation and the WQI was then calculated. The Indicators with greatest weight, according to the PCA, were total coliform, nitrate, fecal coliform, chemical oxygen demand and temperature. The Atlantic forest sub-basin presented the best WQI results, demonstrating the importance of the forested environment in the maintenance of water quality in springs of the Mantiqueira Range region.