Aplicación de fotogrametría y termografía aérea como herramientas para la gestión de un tramo de río.
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Date
2019
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Publisher
Universidad de Concepción
Abstract
El estudio que se presenta a continuación, tiene como objetivo evaluar el uso de técnicas como la fotogrametría y la termografía aérea como herramientas para la gestión de un tramo de río, en específico, analizar el uso de la fotogrametría para modelar eje hidráulico y la termografía para el uso de imágenes térmicas con el fin de detectar puntos de ingreso de agua superficiales y subterráneas esto en un tramo del río Diguillín, ubicado en la zona centro-sur de Chile. Con la elaboración de planes de vuelo y utilizando vehículos no tripulados (UAV) tanto de ala fija como rotatoria, se obtuvieron las imágenes en el espectro visible y térmico, los cuales, a través de diferentes softwares de procesamiento, permitieron generar un ortomosaico, modelo digital de terreno, superficie de agua y ubicación georeferenciadas
de las imágenes térmicas de interés del tramo. Las imágenes térmicas permitieron determinar el ingreso de 2 puntos de aguas superficiales y 2 de aguas subterráneas, estas fueron validadas con visitas a terreno y aforos y, adicionalmente en el caso de las aguas subterráneas, a través del aumento de concentración de Radón. De los resultados obtenidos de la técnica de la termografía aérea, se determinó que es una técnica efectiva, simple y rápida para determinar el ingreso de aguas a un río, especialmente cuando se trata de aguas subterráneas, cuya detección es compleja cuando se trata de tramos largos de cauces naturales. Respecto a la evaluación de la fotogrametría aérea, esta se realizó en forma indirecta, siendo parte de un procedimiento que considera la generación de un modelo hidrodinámico obtenido a través del software HEC RAS y aforos. La evaluación se basó en comparar los resultados que se obtuvieron entre las láminas de aguas generadas por el modelo hidrodinámico y las láminas de agua vistas a través del ortomosaico, determinando un nivel de coincidencia del 54%, esto implica que existen diferencias significativas al utilizar este procedimiento en condiciones de caudales mínimos.
This study aims to evaluate the use of the techniques of photogrammetry and aerial thermography as tools for the management of a section of a river. Specifically, to analyze the use of photogrammetry to model steady flow and thermography to detect points of entry of surface water and groundwater in a section of the Diguillín River, located in the center-south of Chile. With the elaboration of flight plans and using unmanned vehicles (UAV) both fixed and rotary wing, the images were obtained in the visible and thermal spectrum, using different processing software. That allowed to generate an ortomosaic, model digital terrain, water surface and georeferenced location of the thermal images of interest of the section. The thermal images allowed the identification of 2 points of where surface water enters to the river and 2 points of groundwater exfiltration, these were validated with visual inspection and streamflow measurements. Additionally, in the case of groundwater, we use Radon, an environmental tracer, to verify the existence of groundwater imputs. From the results obtained from the technique of aerial thermography, we conclude that it is an effective, simple and fast technique to determine the entry of water into a river, especially when it comes to groundwater, whose detection is complex when it comes to stretches long of natural channels. Regarding the evaluation of aerial photogrammetry, this was done indirectly, being part of a procedure that considers the generation of a hydrodynamic model obtained through the HEC RAS software and gauging. The evaluation was based on comparing the results obtained between the sheets of water generated by the hydrodynamic model and the sheets of water seen through the orthomosaic, determining a level of coincidence of 54%, this implies that there are significant differences when using this procedure under conditions of minimum flows.
This study aims to evaluate the use of the techniques of photogrammetry and aerial thermography as tools for the management of a section of a river. Specifically, to analyze the use of photogrammetry to model steady flow and thermography to detect points of entry of surface water and groundwater in a section of the Diguillín River, located in the center-south of Chile. With the elaboration of flight plans and using unmanned vehicles (UAV) both fixed and rotary wing, the images were obtained in the visible and thermal spectrum, using different processing software. That allowed to generate an ortomosaic, model digital terrain, water surface and georeferenced location of the thermal images of interest of the section. The thermal images allowed the identification of 2 points of where surface water enters to the river and 2 points of groundwater exfiltration, these were validated with visual inspection and streamflow measurements. Additionally, in the case of groundwater, we use Radon, an environmental tracer, to verify the existence of groundwater imputs. From the results obtained from the technique of aerial thermography, we conclude that it is an effective, simple and fast technique to determine the entry of water into a river, especially when it comes to groundwater, whose detection is complex when it comes to stretches long of natural channels. Regarding the evaluation of aerial photogrammetry, this was done indirectly, being part of a procedure that considers the generation of a hydrodynamic model obtained through the HEC RAS software and gauging. The evaluation was based on comparing the results obtained between the sheets of water generated by the hydrodynamic model and the sheets of water seen through the orthomosaic, determining a level of coincidence of 54%, this implies that there are significant differences when using this procedure under conditions of minimum flows.
Description
Tesis presentada para optar al grado de Magíster en Ingeniería Agrícola con mención en Recursos Hídricos
Keywords
Fotogrametría, Thermography, Hidráulica, Métodos termográficos, Vida submarina