Thesis PRONÓSTICO DE CRECIDAS Y NIVELES DE AGUA EN ESTERO MARGA-MARGA, SECTOR VIÑA DEL MAR
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Date
2017
Authors
DÍAZ GÓMEZ, DOMÉNICA SILVANA
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Abstract
El conocimiento anticipado de los eventos meteorológicos que podrían ocasionar crecidas de importancia permite tomar las precauciones necesarias para minimizar eventuales daños. Desde esta perspectiva la predicción meteorológica constituye una herramienta de apoyo en la medida que permite conocer con cierta precisión los estados de la atmósfera que determinan el comportamiento de los sistemas hidrológicos.En el presente estudio se propone una metodología para pronóstico de crecidas y estimación de niveles de agua asociados en el Estero Marga-Marga en el tramo final de su desembocadura al mar. Para ello se realiza una evaluación de algunos de los modelos meteorológicos existentes en cuanto a su habilidad para predecir acertadamente los eventos de precipitaciones observados, se seleccionan los modelos mejor evaluados y en base a sus pronósticos se realiza el pronóstico de caudales y niveles de agua en el estero mediante un modelo hidrológico y un modelo hidráulico, respectivamente.El modelo hidrológico fue implementado en el Sistema de Modelación Hidrológica HEC HMS y permite simular el proceso Precipitación-Escorrentía en la cuenca del Marga-Marga en base a un modelo geométrico y un modelo meteorológico. Para la elaboración del modelo geométrico se dividió el área total de escurrimiento en 19 subcuencas aportantes al Estero Marga-Marga, para las que se calculó los hidrogramas unitarios y se definió las condiciones de infiltración. El modelo meteorológico varía para cada evento de precipitación y permite el cálculo de los hidrogramas de crecida de cada subcuenca, los que posteriormente son transitados a través de cauces y embalses hasta llegar a su punto de salida.El modelo de Ejes Hidráulicos fue implementado en HEC RAS y permite realizar la modelación hidráulica del estero en el tramo comprendido entre el puente Casino y el puente Villanelo.La validación y pre-calibración de los parámetros empleados para el desarrollo del modelo hidrológico fue realizada simulando crecidas con registros de precipitaciones de los años 2015-2016, ingresando los hidrogramas obtenidos como condición de borde al modelo de Ejes Hidráulicos y comparando los niveles de agua calculados con los observados en diversas secciones del estero para el evento de precipitación correspondiente.Con el modelo hidrológico validado y pre-calibrado se obtuvieron los pronósticos de crecida para la tormenta ocurrida entre los días 05 y 06 de agosto de 2015 que constituye el evento más importante registrado el año 2015 y que presenta un periodo de retorno del orden de 5 años. Las crecidas fueron pronosticadas mediante las salidas numéricas de los modelos GFS, ECMWF y WRF con antelaciones de 5 días, 2 días y 1 día, y fueron comparadas con el hidrograma de crecidas y niveles de agua obtenidos a partir del registro de precipitaciones del evento lo que permitió verificar la aplicabilidad de la metodología propuesta.
Anticipated knoledge of meteorological events that could cause major flooding allows us to foresee and minimize possible damages. From this perspective, weather prediction supports tools as it allows us to know with some precision the states of the atmosphere that determine the behavior of hydrological systems.In this study, a methodology for flood forecasting and estimation of associated water levels in the Marga-Marga River in the final stretch of its outlet to the sea is proposed. For this purpose, some existing weather models are evaluated in relation to its ability to accurately predict rainfall events. The best rated models are selected and based on their forecasts for rainfall forecasting flows and water levels in the river is performed using a hydrological model and a hydraulic model, respectively.The hydrological model was implemented in the Hydrologic Modeling System HEC HMS and can simulate the Precipitation-Runoff process in Marga-Marga basin based on a geometric model and a meteorological model. For the development of the geometric model the total area was split in 19 subbasins contributors to Marga-Marga River, for which the hydrograph unit was calculated and infiltration conditions defined. The meteorological model varies for each precipitation event and allows the calculation of flood hydrographs for each subbasin, which are then transited through channels and reservoirs to reach their outlet point.Axles Hydraulic model was implemented in HEC RAS and allows hydraulic modeling of the river in the section between the Casino bridge and the Villanelo bridge.Validation and pre-calibration of the parameters used for the development of hydrological model was conducted simulating flooding with rainfall records of the years 2015-2016, entering hydrographs obtained as a boundary condition to model hydraulic axes and comparing water levels calculated with those observed in various sections of the river for the corresponding precipitation event.With the hydrological model (validated and pre-calibrated) flood forecasts were obtained for the storm occurred between August 5th and August 6th, which was the most important event registered in 2015 and has a return period of 5 years. The floods were predicted by numerical outputs of the GFS, ECMWF and WRF models at lead times of five days, two days and one day, and were compared with the hydrograph floods and water levels obtained from record rainfall event it which allowed to verify the applicability of the proposed methodology
Anticipated knoledge of meteorological events that could cause major flooding allows us to foresee and minimize possible damages. From this perspective, weather prediction supports tools as it allows us to know with some precision the states of the atmosphere that determine the behavior of hydrological systems.In this study, a methodology for flood forecasting and estimation of associated water levels in the Marga-Marga River in the final stretch of its outlet to the sea is proposed. For this purpose, some existing weather models are evaluated in relation to its ability to accurately predict rainfall events. The best rated models are selected and based on their forecasts for rainfall forecasting flows and water levels in the river is performed using a hydrological model and a hydraulic model, respectively.The hydrological model was implemented in the Hydrologic Modeling System HEC HMS and can simulate the Precipitation-Runoff process in Marga-Marga basin based on a geometric model and a meteorological model. For the development of the geometric model the total area was split in 19 subbasins contributors to Marga-Marga River, for which the hydrograph unit was calculated and infiltration conditions defined. The meteorological model varies for each precipitation event and allows the calculation of flood hydrographs for each subbasin, which are then transited through channels and reservoirs to reach their outlet point.Axles Hydraulic model was implemented in HEC RAS and allows hydraulic modeling of the river in the section between the Casino bridge and the Villanelo bridge.Validation and pre-calibration of the parameters used for the development of hydrological model was conducted simulating flooding with rainfall records of the years 2015-2016, entering hydrographs obtained as a boundary condition to model hydraulic axes and comparing water levels calculated with those observed in various sections of the river for the corresponding precipitation event.With the hydrological model (validated and pre-calibrated) flood forecasts were obtained for the storm occurred between August 5th and August 6th, which was the most important event registered in 2015 and has a return period of 5 years. The floods were predicted by numerical outputs of the GFS, ECMWF and WRF models at lead times of five days, two days and one day, and were compared with the hydrograph floods and water levels obtained from record rainfall event it which allowed to verify the applicability of the proposed methodology
Description
Catalogado desde la version PDF de la tesis.
Keywords
ESTERO MARGA-MARGA , MODELO HIDRAULICO , MODELO HIDROLOGICO , PRONOSTICOS