ABSTRACT
The water reservoirs for public supply are environmental assets that need the attention from the whole society. Monitoring limnological variables allows inferring about water resources conditions, besides providing indications of natural or anthropogenic dynamics comprised in the watershed. Rainfall is one of the main mechanisms involved in water quality parameters, and its impact is relevant. The application of Student's t-test and factor analysis/principal components analysis was highly effective for the interpretation of limnological data in the reservoir of the dam of São Pedro, Juiz de Fora, Minas Gerais, Brazil. Student's t-test has enabled to find out which parameters have shown statistically significant seasonal variation. The results of factor analysis/principal components analysis have pointed the most relevant variables in water quality of the source. The analysis of all statistical results has defined the conditioning processes of changes in the variables studied, indicating run-off as the main determinant of the variables that make up the components after rotation of the principal component matrix, Varimax Factor FV1 and FV4, and the organic contribution, not associated with precipitation, reflecting the variables FV2 and FV3.
Keywords:
principal components analysis; water resources; watershed; seasonality.
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