Resumen en español

The streams La Cristalina and La Risaralda are the water sources for the urban area of the Municipality of San Luis, Antioquia. The intention of this study was to develop a map of water quality that serves as base as comparison of the evolution of the streams and allows the high-priority destination of the resources of the Municipality in the improvement of those more critical sections. In order to determine the quality of the water, parameters and some characteristics of the stream that can alter the quality of the water were measured, like substrate of the bed, cover of banks, aquatic habitats, temperature, conductivity, oxygen, pH, coliforms, and aquatic macroinvertebrates. The indices calculated with base in the collected data were: BMWP, ASPT, ETP, Index of Diptera, and equity Index. With the data of the ASPT the map of water quality of both streams was elaborated. The streams are well oxygenated and the rocky conformation of its bed allows the diversity of aquatic macroinvertebrates, nevertheless, in some sections, they are subjected to contamination of domestic and farming origin, which limits their conditions of use.