The present investigation was carried out to estimate the degree of vulnerability to eutrophication by phosphorus in surface waters of the basins of the Rímac, Lurín and Chillón rivers of the Pacific basin, Nanay river of the Atlantic basin and the Azángaro river of the Titicaca basin. The data was collected from the National Water Resources Information System (SNIRH), the National Water Authority (ANA) and the National Meteorology and Hydrology Service (SENAMHI). The Kruskall-Wallis non-parametric test and a Post Hoc analysis between pairs, with Bonferroni adjustment, were used to determine which of the sample groups are significant in terms of vulnerability. For the prediction analyzes of the time series of the variations of the total phosphorus concentration in the basins, the Holt-Winters mathematical model with exponential smoothing was used. It was found, according to the Holt ...