Evaluation of the environmental quality of urban streams, through the use of rapid assessment protocols

Water constitutes one of the most important natural resources of our planet, however, the expansion of urban areas, has caused great degradation in its quality, with diverse associated environmental problems. The diagnosis and monitoring of the aquatic ecosystems are essential to the management of hydric resources. For this endeavour, some Rapid Assessment Protocols has been proposed, in order to make a quick and satisfactory characterization of the environmental quality of different ecosystems. Thus, this study aims to contribute to an evaluation of the degree of deterioration of urban streams in a municipality of the southern Brazil, using an adapted Rapid River Assessment Protocol. The results obtained showed a strong impact of urbanization on the headstream region, the most urbanized of each micro-basin, being the substrate modification, the parameter that most negatively influenced the protocol scores, unlike vegetation, which presented the best indexes. A gradient of environmental quality was observed between the streams, apparently determined by greater or lesser extent of their course in the urban area. As such, it is suggested that conservation and restoration actions focus especially on aspects related to the substrate and, even with better scores, actions to restore the abundance and quality of riparian forests, must be considered.