Here is presented a HEC-HMS hydrological modeling in a small experimental urban watershed, located in a mountainous area of the city of Manizales, Colombia. The study is realized to determine hydrological response in high mountain urban watersheds, where urbanization has created an acute problem relating to floods. This process has produced changes in natural dynamics of watersheds, resulting increases in runoff volumes, peak flows and flow velocities, what in turn increases the floods risk. This problem is most critical in urban mountain watersheds, due to steep slopes, it rises even more flow velocities. From the analysis in the selected watershed, it was found that land use exerts greater control over the hydrological response than high slopes.&nbsp