Uma análise de regressão para determinação do nível de eutrofização de um reservatório do semiárido brasileiro

Abstract

This study aimed to analyze the relation between physicals, chemicals and biological parameters, and their influence on the level of eutrophication in an aquatic ecosystem, using linear regression analysis to identify the best explanatory correlations of trophic characteristics. The Acarape do Meio supply reservoir, located in the metropolitan area of Fortaleza in Ceará, Brazil, was the site chosen for development of the field study. The monitoring of water quality occurred on a monthly basis, during the period from January 2008 to December 2008, with subsurface sampling distributed in seven stations to cover the full reservoir. This dam has a large seasonal variability, with rainfall being one of the most influential factors in the dynamics of limnological characteristics. Regression analysis provided an adjusted model with good correlation (R2=0.95), that showed to be effective for prediction of the eutrophication state in the reservoir and demonstrated to have a good capacity to estimative the Trophic State Index, so the modeled results approached those measured in situ. Thus, this model can be used as a tool for assessing water quality in the selected reservoir.