This article focuses on the simulation of the hydraulic behavior of the Rimac river in a 200-meter section in the Carapongo area of Lima, Peru, in order to determine the floodable areas in the event of increases in flows that exceed historical averages, calculating the levels of water and flow speeds to characterize the effects of flooding on the inhabitants who settle in nearby areas, as happened in March 2017 in the presence of flows of greater magnitudes in the Rimac river. [1] For the development of this article, the hydraulic simulation software called Hec Ras 6.2 was used using a fixed bed model with a fixed cross section channel, for which a topographic survey, granulometric analysis and subsequent estimation of the roughness coefficient were carried out, finally the review of the hydrological information with reference to the events that occurred in March 2017 in the Coastal Niñ...