Impact of Rheology on Hyperconcentrated Flow Applying FLO-2D in the Buena Vista Creek

This article deals with the impact of rheological parameter variation on the choice of the type of sample of alluvial material from the Buena Vista stream in the city of Arequipa, Peru. In the last 4 years, the urbanisation of the Buena Vista hill has witnessed 3 flooding events due to hyper-concentrated flows during the rainy season. The lack of urban planning in the city of Arequipa and the growth of the population has caused the population to invade the bed of this dry creek, which is a latent danger to the lives of these people. For this reason, simulations and analysis of hyper-concentrated flows were carried out in this study to predict flood plains in the event of extreme events by varying the rheology. The topography, soils, geomorphology, and precipitation were characterised by means of satellite maps using ArcGIS software. A hydrological analysis was also carried out using rainfall data from the city of Arequipa for a return period of 5 years. For the simulation of hyperconcentrated flows, the FLO-2D software and the input data from the characterisation stage were used. Three simulations were performed with different rheological parameters. Then, calibration and validation was carried out with the event occurring on 2 January 2021 for each type of sample, and the flooding currents at 2 control points were obtained by means of maps. Finally, the modelling results show that the Gleenwood Type 2 sample is the one that adequately represents the event with a simulated flood flow of 0.40 m at the control points.