Simulation of flood hydrographs in urban channels: a tool for urban planning

Abstract

Floods caused by extreme hydrological events and their consequences are one of the major challenges faced by local government authorities about urban planning. In this context, we studied the urban cross channel sections behaviour located in the Jatobá stream catchment, in the city of Belo Horizonte, Brazil. Different precipitation scenarios were used as input parameters for the hydraulic simulation. For this purpose, the accumulated rainfall was disaggregated and a frequency analysis was performed to compute different duration times (from 10 to 120 minutes) and return periods (from 2 to 100 years). Then, hydrological and hydraulic simulations were carried out using HEC-HMS and HEC-RAS models, respectively. The results showed that the average time until the channel overflows was 58 minutes and the average duration time for the overflow was 28 minutes. The channel overflowed in 77.14% of the simulated scenarios. The simulations were carried out for different rainfall return periods and time duration to characterize extreme events for this catchment, aiding the decision- making process and assisting in the development of strategies to improve the drainage system.