Browsing by Author "Pinos Flores, Juan Andres"

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Evaluation of 1D hydraulic models for the simulation of mountain fluvial floods: a case study of the Santa Bárbara river in Ecuador
(2019) Pinos Flores, Juan Andres; Timbe Castro, Edison Patricio; Timbe Castro, Luis Manuel
River flooding is a key topic for water managers because of social and economic losses it can cause. The complex topography and dynamics of mountain rivers has limited the analysis of their behavior during flood events (e.g., sediment transport, flooding). This study aims to test the performance of three hydraulic 1D models (HEC-RAS, MIKE 11, and Flood Modeller) to estimate inundation water levels for a mountain river. The evaluation of these models was performed considering steady state conditions through 10 scenarios, i.e. five discharge return periods, and two types of cross sections data (a) type I, a detailed field survey complemented with information extracted from DEM, derived from LiDAR; and (b) type II, cross sections exclusively derived from the DEM. The research was conducted for a reach of 5 km of the Santa Bárbara River, with an average slope of 0.25%. HHEC-RAS model results for cross sections type I, were previously validated and therefore used as reference for comparison between other models and scenarios. The goodness-of-fit between models was measured based on the Nash-Sutcliffe model efficiency coefficient (EF). The main goal of the current study was to determine the variability of inundation level results compared with a validated model as reference, using the same input data for the three modeling packages. Our analysis shows that, when using cross section type I, the evaluated modeling packages yield similar results (EF were between 0.94 and 0.99). On the other hand, the goodness of fit decreased when using type II data, with an average EF of 0.98 (HEC-RAS), 0.88 (Flood Modeller) and 0.85 (MIKE 11) when compared to the reference model. The authors conclude that it is highly recommend for practitioners to use geometric data type I instead of type II in order to obtain similar performance in the tested models. Only HEC-RAS type II has the same performance as type I models (average EF of 0.98).
Métodos para la evaluación del riesgo de inundación fluvial: revisión de literatura y propuesta metodológica para Ecuador
(2017) Pinos Flores, Juan Andres; Timbe Castro, Luis Manuel; Orellana Vintimilla, Daniel Augusto
Las inundaciones representan uno de los peligros naturales más frecuentes a nivel global, ocasionando considerables pérdidas económicas y sociales en las poblaciones afectadas. En las últimas décadas, las propuestas basadas en la evaluación del riesgo son cada vez más aceptadas e incorporadas en la gestión del riesgo de inundaciones. A pesar del progreso considerable en el desarrollo de herramientas de estimación de pérdidas, éstas aún presentan incertidumbres altas y disparidades que a menudo llevan a cuestionar su calidad. Este trabajo presenta una revisión exhaustiva y actualizada de las diferentes herramientas analíticas y metodológicas incorporadas en varios modelos existentes. El análisis comparativo de las metodologías mostró que los componentes y características incluidas por los diferentes métodos son altamente heterogéneos y la gran mayoría no incorporan una validación explícita de los resultados del modelo. Esta comparación requirió de una profunda comprensión de las estructuras, mecanismos y supuestos subyacentes de cada método. Finalmente, el artículo presenta las características generales y los principales componentes de una propuesta metodológica para la evaluación analítica de estimación de pérdidas por inundación para el Ecuador, a partir de la síntesis de todos los métodos evaluados y en función de la información disponible.
Performance assessment of two-dimensional hydraulic models for generation of flood inundation maps in mountain river basins
(2019) Timbe Castro, Luis Manuel
Abstract Hydraulic models for the generation of flood inundation maps are not commonly applied in mountain river basins because of the difficulty in modeling the hydraulic behavior and the complex topography. This paper presents a comparative analysis of the performance of four two-dimensional hydraulic models (HEC-RAS 2D, Iber 2D, Flood Modeller 2D, and PCSWMM 2D) with respect to the generation of flood inundation maps. The study area covers a 5-km reach of the Santa Barbara River located in the Ecuadorian Andes, at 2330 masl, in Gualaceo. The model's performance was evaluated based on the water surface elevation and flood extent, in terms of the mean absolute difference and measure of fit. The analysis revealed that, for a given case, Iber 2D has the best performance in simulating the water level and inundation for flood events with 20- and 50-year return periods, respectively, followed by Flood Modeller 2D, HEC-RAS 2D, and PCSWMM 2D in terms of their performance. Grid resolution, the way in which hydraulic structures are mimicked, the model code, and the default value of the parameters are considered the main sources of prediction uncertainty.