Abstract

This work aims to perform a comparative analysis between the Hec-RAS and IBER models, in the hydraulic evaluation of rivers with structures such as bridges. The case of application was the La Guardia creek, located in the road that communicates the cities of Barquisimeto-Quíbor, Venezuela. The first phase of the study consisted in the comparison of the models from the conceptual point of view and the management of both. The second phase focused on the case study, and the comparison of the results obtained from the hydraulic analysis. It was observed that the behavior in both models presented great similarity in the flow profile as in the regime. Upstream of the two bridges predominate the subcritical regime, where the highest depths and the lowest velocities are present. The opposite occurs downstream of the two bridges, where the supercritical regime prevails, high speeds and minimum depths. It is concluded that, for rivers with simple geometry and preferably with a single bridge, the Hec-RAS one-dimensional software is presented as the best alternative of use due to the ease of data entry, providing reliable results in a shorter time. While the IBER package is two-dimensional, it represents a better option for modeling rivers with more irregular geometries, when there is a special interest in the hydraulic behavior of the flow through stirrups and stacks, and having two or more bridges with separation reduced.

Abstract

Iber es un modelo numérico bidimensional de simulación de flujo turbulento en lámina libre en régimen no-permanente, y de procesos medioambientales en hidráulica fluvial. Desde el lanzamiento de la primera versión, que incluía un motor de cálculo hidrodinámico completamente acoplado con procesos de transporte de sedimento y turbulencia, Iber ha ido evolucionando hasta convertirse en una herramienta de modelización de flujo en lámina libre de procesos ambientales de elevada complejidad. En este documento se presentan los desarrollos realizados para la versión 3, donde los avances son principalmente en cuatro líneas de investigación: un nuevo módulo de drenaje urbano, un avance significativo en las capacidades del módulo de hidrología, un nuevo módulo de erosión de suelos, y un nuevo módulo para el cálculo del transporte de sedimentos considerando material no uniforme (mezclas). Asimismo, todos los trabajos han ido acompañados por una tarea transversal de mejora de la interfaz, tanto para los módulos ya existentes, como la creación de nuevas ventanas y menús para los nuevos módulos con el objetivo de mejorar todo el flujo de trabajo.

Abstract

Approximately 70,000 Spanish off-stream reservoirs, many of them irrigation ponds, need to be evaluated in terms of their potential hazard to comply with the new national Regulation of the Hydraulic Public Domain. This requires a great engineering effort to evaluate different scenarios with two-dimensional hydraulic models, for which many owners lack the necessary resources. This work presents a simplified methodology based on machine learning to identify risk zones at any point in the vicinity of an off-stream reservoir without the need to elaborate and run full two-dimensional hydraulic models. A predictive model based on random forest was created from datasets including the results of synthetic cases computed with an automatic tool based on the two-dimensional numerical software Iber. Once fitted, the model provided an estimate on the potential hazard considering the physical characteristics of the structure, the surrounding terrain and the vulnerable locations. Two approaches were compared for balancing the dataset: the synthetic minority oversampling and the random undersampling. Results from the random forest model adjusted with the random undersampling technique showed to be useful for the estimation of risk zones. On a real application test the simplified method achieved 91% accuracy.

Abstract

Floods produce enormous human and material losses every year. Evaluating their extent and severity, and especially simulating possible future scenarios can improve the response, mitigation and prevention of the effects of this phenomenon. This paper presents a methodology to reproduce the extent of floods produced by channel overflows and recorded by satellite images, identifying the maximum discharge that produced it by means of the numerical solution of the 2D shallow water equations and Differential Evolution. The objective is to minimize the difference between the extent of the flooded area recorded in the satellite images, and that obtained in the simulation by adjusting the maximum value of the flow curve used at the entrance of the channel in the solution domain. The proposal is applied to data and images corresponding to an area located south of the city of Villahermosa, in the Mexican state of Tabasco, which is an area susceptible to flooding by the overflow of the Río de la Sierra. Our proposal shows that it is possible to have more accurate information on the extent and height of water in the flooded area than that shown by the satellite, which can be used as information for prevention and mitigation plans for the adverse effects of flooding. Palabras clave: Modelado de inundaciones, gasto máximo en ríos, Iber, evolución diferencial