RESUMO
Surface water quality is deteriorating due to the increase of urbanization which increases the load of stormwater and wastewater discharged into rivers. To evaluate the quality of an urban river (Annaba, northeastern Algeria), multivariate statistical analyses were applied to the physicochemical measures of 38 parameters. The application of principal component analysis and factor analysis pointed out 19 dominant components, explaining 83.40% of the variance. Reducing the amount of data will allow a reduction in the number of parameters that need to be analysed to have sufficient information on the water quality. An analysis of the statistical tools' results and effective impervious area leads to an estimation of the urbanization threshold level at which the impact on water quality occurs. Estimating the threshold of impervious areas to abide will ensure urban development while protecting the quality of water and environmental health.