ESTIMACIÓN DE SEDIMENTOS EN LA CUENCA PILCOMAYO USANDO UN PRODUCTO DE PRECIPITACIÓN COMBINADO CON SENSORES ABORDO DE SATÉLITES
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Abstract
El objetivo de este estudio es la obtención de un producto de precipitación combinando sensores remotos con mediciones en tierra y explorar sus posibles aplicaciones para estimar caudal líquido y sólido. El presente estudio se concentra en la porción de la cuenca Pilcomayo en territorio boliviano. Se emplearon dos productos de precipitación con base satelital: GSMaP y CHIRPS. Empleando un ajuste iterativo de estos productos con pluviómetros se han obtenido dos productos denominados GS y CH respectivamente. Para realizar la validación de los productos generados se comparó con la grilla GMET de 5km de resolución del Balance Hídrico Superficial de Bolivia (BHSB). Como se ha encontrado que el producto GS muestra un performance un poco mayor al de CH, usando la precipitación combinada GS se ha procedido a estimar el caudal por subcuencas. Para este último proceso se ha utilizado los coeficientes de escorrentía reportado en el BHSB. Se ha logrado estimar el caudal líquido empleando el producto de precipitación combinado GS y coeficientes de escorrentía reportados en el BHSB. Primeramente, se ha estimado los caudales específicos por subcuenca para el periodo 2001-2015. Se ha evidenciado que las magnitudes de caudal líquido son mayores en la zona de los llanos y congruente con los valores de precipitación. Posteriormente se ha estimado el caudal líquido en las áreas de aporte de nueve estaciones hidrométricas para comparar con los caudales reportados en los 70s, 80s y 90s. Si bien son periodos diferentes de análisis, se ha notado consistencia de los caudales simulados con los reportados en la mitad de las estaciones. En la estación hidrométrica de Villamontes, que cubre 91 % de la zona de estudio, se ha estimado 6310 millones de m³ de agua en promedio interanual para el periodo 2001-2015. Posteriormente se ha estimado el caudal sólido en las mismas estaciones. En Villamontes se ha estimado 159 millones de Toneladas al año de producción de sedimento. De esta manera en el presente estudio se ha aprovechado del producto de precipitación combinado por subcuenca para estimar la variación espacial del caudal líquido y sólido en la zona de estudio. Se ha notado la importancia de la estimación de la precipitación como variable clave de los procesos hidrológicos, que bien puede ser aún mejor aprovechado utilizando modelos hidrológicos distribuidos para convertir la precipitación en caudal y a su vez en estimar la producción de sedimentos en una cuenca.
The objective of this study is to obtain a precipitation product combining remote sensors with ground measurements and to explore potential applications to estimate liquid and solid flow. This study focuses on the upper portion of the Pilcomayo basin within Bolivia. Two satellite-based precipitation products were used: GSMaP and CHIRPS. Using an iterative adjustment of these products with rain gauges, two products were generated namely GS and CH, respectively. To carry out the validation of generated products, they were compared against GMET grid of 5 km resolution. As it has been found that the GS product showing a slightly higher performance than CH, the combined GS product was employed to estimate the river discharge at sub-basin level. The discharge has been estimated using the combined precipitation product GS and reported runoff coefficients. Firstly, the specific flow at each sub-basin has been estimated for the period 2001-2015. It has been shown that the magnitudes of the river discharged were greater in the plain area and consistent with the precipitation pattern. Subsequently, the discharge in the contribution areas of nine hydrometric stations has been estimated to compare with the observations reported in the 70s, 80s and 90s. Although they are different periods of analysis, the simulated flows have been noted to be consistent with those reported in some stations. For example, at Villamontes hydrometric station, which covers 91% of the study area, 6310 million m³ of water have been estimated on an annual basis for the period 2001-2015. Subsequently, the solid flow at the same stations has been estimated. At Villamontes, it was estimated 159 million tons per year of sediment production. In this way, the present study has taken advantage of the combined precipitation product per sub-basin to estimate the spatial variation of the liquid and solid flow in the study area. The importance of estimating precipitation has been noted as a key variable in the hydrological processes, which may be even better exploited using distributed hydrological models to convert precipitation to flow and estimate the production of sediments in a basin.
The objective of this study is to obtain a precipitation product combining remote sensors with ground measurements and to explore potential applications to estimate liquid and solid flow. This study focuses on the upper portion of the Pilcomayo basin within Bolivia. Two satellite-based precipitation products were used: GSMaP and CHIRPS. Using an iterative adjustment of these products with rain gauges, two products were generated namely GS and CH, respectively. To carry out the validation of generated products, they were compared against GMET grid of 5 km resolution. As it has been found that the GS product showing a slightly higher performance than CH, the combined GS product was employed to estimate the river discharge at sub-basin level. The discharge has been estimated using the combined precipitation product GS and reported runoff coefficients. Firstly, the specific flow at each sub-basin has been estimated for the period 2001-2015. It has been shown that the magnitudes of the river discharged were greater in the plain area and consistent with the precipitation pattern. Subsequently, the discharge in the contribution areas of nine hydrometric stations has been estimated to compare with the observations reported in the 70s, 80s and 90s. Although they are different periods of analysis, the simulated flows have been noted to be consistent with those reported in some stations. For example, at Villamontes hydrometric station, which covers 91% of the study area, 6310 million m³ of water have been estimated on an annual basis for the period 2001-2015. Subsequently, the solid flow at the same stations has been estimated. At Villamontes, it was estimated 159 million tons per year of sediment production. In this way, the present study has taken advantage of the combined precipitation product per sub-basin to estimate the spatial variation of the liquid and solid flow in the study area. The importance of estimating precipitation has been noted as a key variable in the hydrological processes, which may be even better exploited using distributed hydrological models to convert precipitation to flow and estimate the production of sediments in a basin.
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Vol. 20, No. 1