Validación de una metodología empírica para evaluar modificaciones del riesgo de inundación urbana ante escenarios hipotéticos de uso del suelo

Abstract

In order to analyze the incidence of urban and peri-urban green spaces in the water dynamics of urban subbasins of the city of Rosario, a methodology was proposed in previous papers to estimate the changes in the urban flood risk in front of land use changes. The methodology is an empirical approach and is based on Mulvaney's rational formula together with the expression of Kieffer and Chu for the IDR curves, being applied to 5 urban watersheds of Rosario, considering a base (current) scenario of land use and three future scenarios with / without availability of green spaces. In this work the empirical methodology is validated applying a conventional statistical estimation to the previous basins. It contemplates the estimation of geomorphological and hydrological parameters of the basins for the base scenario and future scenarios, applying the Colorado Urban Hydrograph Procedure, CUHP. Rosario Aero's rainfall series (71 years of extension, around 7,000 events) are processed, constructing total and net rainfall hyetographs by means of a runoff coefficient by basin and scenario. Series of daily flows are generated and annual maxima are selected, assigning probability distribution functions (Gumbel). Finally, for each basin and scenario the exceedance probability changes are obtained for the current and future series of flows. When comparing the results with the empirical methodology, very high correlation coefficients (0.9975) and high Nash-Sutcliffe efficiency coefficients (0.9929) are achieved. Consequently, the so-called empirical methodology is a simple and effective tool for estimating changes in flood risk in the face of changes in land use evaluated through the runoff coefficient.