Factors controlling flooding at the Tonalá river mouth (Mexico)

Abstract

AbstractThis investigation presents an integrated study for the identification of coastal and fluvial forcing, in the generation of flood events in the lower area of the Tonalá River. The methodology is designed to reduce some of the uncertainties in the results and is comprised by high‐quality field measurements, a two‐dimensional numerical model and light ranging and detection data. Under typical conditions, results show good agreement between numerical and measured data. Investigation of mesh resolution effects and roughness parameterisation along the floodplain demonstrates the grid independence of the results and enabled the selection of a realistic roughness value for the floodplain. Results imply a sensitivity of the region to the combined river and coastal forcing. This study demonstrates that a good description of the terrain elevation, acquisition of high‐quality bathymetric data and proper calibration of the roughness parameters provide the adequate set‐up for the identification of vulnerable areas to flood events generated by river discharges and storm surges. The combined scenarios of high discharges and storm surges showed a delicate balance between river and coastal fluxes within this system. The approach could be useful for both, the generation of flood management strategies and the understanding of the role of driving physical processes.