Sedimentary flow quantification of the amazon basin of Peru

Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Recursos HídricosEl presente estudio, trata sobre la cuantificación del flujo sedimentario, el grado de incertidumbre en las metodologías empleadas y la variabilidad temporal de los flujos líquidos y sólidos. Para este trabajo se consideró 8 estaciones hidrológicas y sedimentarias de la cuenca amazónica peruana, tres en el pie de monte y cinco en la llanura, sobre los ríos, Marañón, Huallaga, Ucayali, Amazonas, El Tigre y Napo. El período de observación es del 2004 a 2009. Para la determinación de flujo de sedimentos en suspensión, se utilizó muestreos superficiales recolectados cada diez días por una persona del lugar, además de los datos de caudal sólido, obtenidos en campañas de campo realizadas cada tres meses. La evaluación de los flujos sedimentarios se realizó a través de dos metodologías de cálculo, una de interpolación de los datos de concentraciones especializados cada diez días y la otra de extrapolación, mediante de la relación caudal líquido vs caudal sólido. El cálculo de la carga de fondo se fundamentó en el perfil de concentraciones de Rouse y el perfil de velocidades. Se muestra por primera vez la utilización del perfil de Rouse y la turbiedad como una herramienta para el análisis espacial, para los ríos amazónicos peruanos. Para el período establecido y con un total de 1 547 muestras, se determinó que la cuenca amazónica peruana transporta 629*106 ± 36% t/año de sedimentos en suspensión al año, y un caudal de 36 000 m3/s. El río Ucayali aporta la mayor cantidad de sedimentos con 61.2%, la cuenca del río Marañón 30.4% y la cuenca el Napo 8.4%. En el pie de monte el río Marañón conduce 162 106 ± 24% t/año, el río Huallaga 81 106 ± 19% t/año, y el río Ucayali 239 106 ± 12% t/año. Se observa una fuerte variabilidad temporal tanto en caudales líquidos como sólidos, sobre todo en los ríos de montaña, que se atenúa con forme se acerca a la planicieThe present study deals with the quantification of sedimentary transport, the degree of uncertainty in the methodologies employed, and the temporal variability of the liquid flow and sedimentary transport. In this study, we considered 8 hydrological and sedimentary stations in the Peruvian Amazonian River basin, three on the piedmont and five in the plain, specifically on the Marañón, Huallaga, Ucayali, Amazon, Tigre and Napo rivers. The period of observation is from 2004 until 2009. For the determination of the suspended sediments flow, surface samplings were collected every ten days by a local person, in addition to the collection of sedimentary transport data, obtained during field campaigns made every three months. The evaluation of the sedimentary flows was made through two methodologies of calculation; one of interpolation of the data of concentrations obtained every ten days and the other of extrapolation, using the relation between liquid flow versus sediment transport. The calculation of the bottom load was based on the Rouse´s concentration and velocity profiles. For the first time, Rouse´s profile and the turbidity profile were used as a tool of spatial analysis for the Peruvian Amazonian rivers. For the period of study and with a total of 1 547 samples, we determined that the Peruvian Amazonian River basin transports 629*106 ± 36% t year-1 of sediments in suspension, and a liquid flow rate of 36 000 m3s-1. The Ucayali River contributes the greatest amount of sediments with 61.2%, the Marañon River Basin with 30.4%, and the Napo River Basin with 8.4%. At the piedmont, the Marañon river transports 162*106 t year-1 (± 24%), the Huallaga river 81*106 t year-1 (± 19%) and the Ucayali river 239*106 t year-1(± 12%). Large temporal variability in liquid as well as sediment fluxes is observed, mainly in the mountain rivers, which is attenuated approaching the plainTesi

Propagation of suspended sediment flux in the Amazon river from Tamshiyacu gauging station in Peru to Obidos gauging in Brazil : spatio-temporal variability

Le bassin amazonien est considéré au niveau mondial comme l'un des principaux apports de sédiments à l'Océan Atlantique. Comprendre la distribution spatiale et temporelle des flux sédimentaires est l'objectif de cette étude pour laquelle on a choisi quatre stations hydrométriques de suivi réparties tout au long de l'Amazone depuis sa formation au Pérou jusqu'à environ 800 km de son embouchure au Brésil (Óbidos). Pour atteindre cet objectif, on a mis en place pour chaque station un échantillonnage décadaire en surface et une exploration totale de leur section à différentes périodes de l'année. Des profils de turbidité et des échantillons pour la granulométrie sur toute la section faisaient également partie de ce suivi. Sur les stations andines et sub-andines, la turbulence de l'écoulement jointe aux faibles profondeurs permet l'ascension de sédiments grossiers vers la surface. Par conséquent, on observe une relation directe entre la concentration de sédiments en suspension de surface et la concentration moyenne dans la section, ce qui permet un calcul simple des flux sédimentaires et d'arriver à une valeur de 540 Mt/an pour qui concerne l'apport du basin péruvien de l'Amazone. Dans la plaine brésilienne, le contexte change, les profondeurs moyennes se situent entre 40 et 100 m de telle sorte que la présence de sable en surface est quasi nulle. Cependant, l'analyse des résultats à la station d'Óbidos montre qu'il existe une relation directe entre la concentration de sédiments de surface et la concentration moyenne de sédiments fins dans la section alors que la concentration moyenne de sédiments grossiers dans la section est, elle, em relation directe avec le débit liquide. En différenciant ainsi le calcul suivant ces deux types de sédiments, on arrive à une valeur de flux de 1100 Mt/an transitant par Óbidos, dont 60% correspond au flux des sédiments fins et 40% aux grossiers. On a utilisé la turbidité pour par courbes de calibration em funtion da granulometrie parvenir aux valeurs de concentration. On a utilisé le modèle de Rouse pour différencier le signal de concentration obtenu avec la turbidité résultat du signal de le deux types de sediment. On a constaté que les granulométries en présence sont les mêmes tout au long du régime hydrologique mais que ce sont les proportions de chacune d'entre elles qui varient. Aussi a-t-on abouti à des profils de concentration pour sédiments fins et des profils pour sédiments grossiers. En montée de crue, les profils de concentration présentent un gradient bien marqué pour les sédiments fins, alors qu'en période de crue ce gradient est contrôlé par les sables et les profils de fines sont alors verticaux et constants sur toute la section. Ces résultats montrent qu'il est possible de prédire, en Amazonie, les profils de concentration à partir de la turbidité.The sediments flux in Amazon Basin have an important role on the aquatic biodiversity and richness in the floodplains because the nutrients and organic matter attached on suspended sediments are deposited in these zones. The aim of this study is to understand the spatial and temporal distribution of sediments flux in the Amazon River, therefore were select four gauging station located along of Amazon Riven from Peru to Brazil. In each gauging station was make superficial samples each ten days and samples in the section in different times of hydrological period. Turbidity profiles and granulometry measuring were made too in each gauging station. In the Andean region, it is observed a relationship between the suspended sediments concentration and discharge, however, this relationship become a hysteresis in the plain especially in the Óbidos gauging station located at 870 km before of mouth. This result can be by the contribution of influx poor in suspended sediments from Guyanese and Brazilian shields. In 3000 km of long from Peru to Brazil plain, the suspended sediments is composed by two well-defined types of suspended sediments: fine sediments (10-20 µm) and coarse sediments (100-250 µm). The percentage of each type of sediments in the main river is different during the hydrologic regime. Peak of fine sediments is observed in the same period of peak of rainfall (December to March) and peak of coarse sediments is observed in flood period (May to July). The Andean and sub-Andean basin gauging station show the coarse sediments in surface due to great turbulence and low depths. Therefore, this gauging station show a relationship between the suspended sediments concentration in surface and average suspended sediments concentration in section, with this relation is possible to calculate the suspended sediments flux. Hence the Peruvian basin provide 540 Mt year -1. However in the Brazilian plain the context is different, the depth is from 40 to 100 m, becoming almost null the presence of coarse sediments in the surface. Therefore, cannot use the relationship between suspended sediments concentration in surface and average suspended sediments concentration in section. When the Óbidos gauging station is analysed, it found there is a relationship between suspended sediments concentration in surface and average of fine suspended sediments concentration. It is observed too, that there is the relationship between coarse suspended sediments concentration and discharge. Therefore, it is possible to calculate of suspended sediments flux using these two relationships. The Amazon River export 1100 Mt year-1 of suspended sediments at Óbidos gauging station, of which 60% correspond at fine sediments flux and 40% to coarse sediments flux. It is observed that the suspended sediments are sensitivity of climate variability, generally El Niño events is associate with increase of fine suspended sediments and La Niña events increase a percentage of coarse sediments in Amazon River. It is using the turbidity for determinate of suspended sediments concentration, we use this technique due the high frequency in acquisition of data. However for use the turbidity is necessary the previous calibration. It was observed that the turbidity signal is an addition to the signal emitted by the particles in one sample and with this assumption the Rose model was used to separate the concentration signal obtained by the turbidity of the two types of sediments present in the Amazon River, fine particles and sand. Therefore, it was obtained the concentration profiles to fine sediments and the concentration profiles to the sand. It is observed during the rising period that the fine sediments profiles show a strong gradient, however in the flood periods this gradient reduce come a constant in all section. These results show that turbidity and Rouse model can be used for prediction of suspended concentration in Amazon River

Propagation des flux de sédiments en suspension sur l'Amazone de Tamshiyacu (Pérou) à Obidos (Brésil) : variabilité spatio-temporelle

The sediments flux in Amazon Basin have an important role on the aquatic biodiversity and richness in the floodplains because the nutrients and organic matter attached on suspended sediments are deposited in these zones. The aim of this study is to understand the spatial and temporal distribution of sediments flux in the Amazon River, therefore were select four gauging station located along of Amazon Riven from Peru to Brazil. In each gauging station was make superficial samples each ten days and samples in the section in different times of hydrological period. Turbidity profiles and granulometry measuring were made too in each gauging station. In the Andean region, it is observed a relationship between the suspended sediments concentration and discharge, however, this relationship become a hysteresis in the plain especially in the Óbidos gauging station located at 870 km before of mouth. This result can be by the contribution of influx poor in suspended sediments from Guyanese and Brazilian shields. In 3000 km of long from Peru to Brazil plain, the suspended sediments is composed by two well-defined types of suspended sediments: fine sediments (10-20 µm) and coarse sediments (100-250 µm). The percentage of each type of sediments in the main river is different during the hydrologic regime. Peak of fine sediments is observed in the same period of peak of rainfall (December to March) and peak of coarse sediments is observed in flood period (May to July). The Andean and sub-Andean basin gauging station show the coarse sediments in surface due to great turbulence and low depths. Therefore, this gauging station show a relationship between the suspended sediments concentration in surface and average suspended sediments concentration in section, with this relation is possible to calculate the suspended sediments flux. Hence the Peruvian basin provide 540 Mt year -1. However in the Brazilian plain the context is different, the depth is from 40 to 100 m, becoming almost null the presence of coarse sediments in the surface. Therefore, cannot use the relationship between suspended sediments concentration in surface and average suspended sediments concentration in section. When the Óbidos gauging station is analysed, it found there is a relationship between suspended sediments concentration in surface and average of fine suspended sediments concentration. It is observed too, that there is the relationship between coarse suspended sediments concentration and discharge. Therefore, it is possible to calculate of suspended sediments flux using these two relationships. The Amazon River export 1100 Mt year-1 of suspended sediments at Óbidos gauging station, of which 60% correspond at fine sediments flux and 40% to coarse sediments flux. It is observed that the suspended sediments are sensitivity of climate variability, generally El Niño events is associate with increase of fine suspended sediments and La Niña events increase a percentage of coarse sediments in Amazon River. It is using the turbidity for determinate of suspended sediments concentration, we use this technique due the high frequency in acquisition of data. However for use the turbidity is necessary the previous calibration. It was observed that the turbidity signal is an addition to the signal emitted by the particles in one sample and with this assumption the Rose model was used to separate the concentration signal obtained by the turbidity of the two types of sediments present in the Amazon River, fine particles and sand. Therefore, it was obtained the concentration profiles to fine sediments and the concentration profiles to the sand. It is observed during the rising period that the fine sediments profiles show a strong gradient, however in the flood periods this gradient reduce come a constant in all section. These results show that turbidity and Rouse model can be used for prediction of suspended concentration in Amazon River.Le bassin amazonien est considéré au niveau mondial comme l'un des principaux apports de sédiments à l'Océan Atlantique. Comprendre la distribution spatiale et temporelle des flux sédimentaires est l'objectif de cette étude pour laquelle on a choisi quatre stations hydrométriques de suivi réparties tout au long de l'Amazone depuis sa formation au Pérou jusqu'à environ 800 km de son embouchure au Brésil (Óbidos). Pour atteindre cet objectif, on a mis en place pour chaque station un échantillonnage décadaire en surface et une exploration totale de leur section à différentes périodes de l'année. Des profils de turbidité et des échantillons pour la granulométrie sur toute la section faisaient également partie de ce suivi. Sur les stations andines et sub-andines, la turbulence de l'écoulement jointe aux faibles profondeurs permet l'ascension de sédiments grossiers vers la surface. Par conséquent, on observe une relation directe entre la concentration de sédiments en suspension de surface et la concentration moyenne dans la section, ce qui permet un calcul simple des flux sédimentaires et d'arriver à une valeur de 540 Mt/an pour qui concerne l'apport du basin péruvien de l'Amazone. Dans la plaine brésilienne, le contexte change, les profondeurs moyennes se situent entre 40 et 100 m de telle sorte que la présence de sable en surface est quasi nulle. Cependant, l'analyse des résultats à la station d'Óbidos montre qu'il existe une relation directe entre la concentration de sédiments de surface et la concentration moyenne de sédiments fins dans la section alors que la concentration moyenne de sédiments grossiers dans la section est, elle, em relation directe avec le débit liquide. En différenciant ainsi le calcul suivant ces deux types de sédiments, on arrive à une valeur de flux de 1100 Mt/an transitant par Óbidos, dont 60% correspond au flux des sédiments fins et 40% aux grossiers. On a utilisé la turbidité pour par courbes de calibration em funtion da granulometrie parvenir aux valeurs de concentration. On a utilisé le modèle de Rouse pour différencier le signal de concentration obtenu avec la turbidité résultat du signal de le deux types de sediment. On a constaté que les granulométries en présence sont les mêmes tout au long du régime hydrologique mais que ce sont les proportions de chacune d'entre elles qui varient. Aussi a-t-on abouti à des profils de concentration pour sédiments fins et des profils pour sédiments grossiers. En montée de crue, les profils de concentration présentent un gradient bien marqué pour les sédiments fins, alors qu'en période de crue ce gradient est contrôlé par les sables et les profils de fines sont alors verticaux et constants sur toute la section. Ces résultats montrent qu'il est possible de prédire, en Amazonie, les profils de concentration à partir de la turbidité

Propagation of suspended sediment flux in the Amazon river from Tamshiyacu gauging station in Peru to Obidos gauging in Brazil : spatio-temporal variability

Le bassin amazonien est considéré au niveau mondial comme l'un des principaux apports de sédiments à l'Océan Atlantique. Comprendre la distribution spatiale et temporelle des flux sédimentaires est l'objectif de cette étude pour laquelle on a choisi quatre stations hydrométriques de suivi réparties tout au long de l'Amazone depuis sa formation au Pérou jusqu'à environ 800 km de son embouchure au Brésil (Óbidos). Pour atteindre cet objectif, on a mis en place pour chaque station un échantillonnage décadaire en surface et une exploration totale de leur section à différentes périodes de l'année. Des profils de turbidité et des échantillons pour la granulométrie sur toute la section faisaient également partie de ce suivi. Sur les stations andines et sub-andines, la turbulence de l'écoulement jointe aux faibles profondeurs permet l'ascension de sédiments grossiers vers la surface. Par conséquent, on observe une relation directe entre la concentration de sédiments en suspension de surface et la concentration moyenne dans la section, ce qui permet un calcul simple des flux sédimentaires et d'arriver à une valeur de 540 Mt/an pour qui concerne l'apport du basin péruvien de l'Amazone. Dans la plaine brésilienne, le contexte change, les profondeurs moyennes se situent entre 40 et 100 m de telle sorte que la présence de sable en surface est quasi nulle. Cependant, l'analyse des résultats à la station d'Óbidos montre qu'il existe une relation directe entre la concentration de sédiments de surface et la concentration moyenne de sédiments fins dans la section alors que la concentration moyenne de sédiments grossiers dans la section est, elle, em relation directe avec le débit liquide. En différenciant ainsi le calcul suivant ces deux types de sédiments, on arrive à une valeur de flux de 1100 Mt/an transitant par Óbidos, dont 60% correspond au flux des sédiments fins et 40% aux grossiers. On a utilisé la turbidité pour par courbes de calibration em funtion da granulometrie parvenir aux valeurs de concentration. On a utilisé le modèle de Rouse pour différencier le signal de concentration obtenu avec la turbidité résultat du signal de le deux types de sediment. On a constaté que les granulométries en présence sont les mêmes tout au long du régime hydrologique mais que ce sont les proportions de chacune d'entre elles qui varient. Aussi a-t-on abouti à des profils de concentration pour sédiments fins et des profils pour sédiments grossiers. En montée de crue, les profils de concentration présentent un gradient bien marqué pour les sédiments fins, alors qu'en période de crue ce gradient est contrôlé par les sables et les profils de fines sont alors verticaux et constants sur toute la section. Ces résultats montrent qu'il est possible de prédire, en Amazonie, les profils de concentration à partir de la turbidité.The sediments flux in Amazon Basin have an important role on the aquatic biodiversity and richness in the floodplains because the nutrients and organic matter attached on suspended sediments are deposited in these zones. The aim of this study is to understand the spatial and temporal distribution of sediments flux in the Amazon River, therefore were select four gauging station located along of Amazon Riven from Peru to Brazil. In each gauging station was make superficial samples each ten days and samples in the section in different times of hydrological period. Turbidity profiles and granulometry measuring were made too in each gauging station. In the Andean region, it is observed a relationship between the suspended sediments concentration and discharge, however, this relationship become a hysteresis in the plain especially in the Óbidos gauging station located at 870 km before of mouth. This result can be by the contribution of influx poor in suspended sediments from Guyanese and Brazilian shields. In 3000 km of long from Peru to Brazil plain, the suspended sediments is composed by two well-defined types of suspended sediments: fine sediments (10-20 µm) and coarse sediments (100-250 µm). The percentage of each type of sediments in the main river is different during the hydrologic regime. Peak of fine sediments is observed in the same period of peak of rainfall (December to March) and peak of coarse sediments is observed in flood period (May to July). The Andean and sub-Andean basin gauging station show the coarse sediments in surface due to great turbulence and low depths. Therefore, this gauging station show a relationship between the suspended sediments concentration in surface and average suspended sediments concentration in section, with this relation is possible to calculate the suspended sediments flux. Hence the Peruvian basin provide 540 Mt year -1. However in the Brazilian plain the context is different, the depth is from 40 to 100 m, becoming almost null the presence of coarse sediments in the surface. Therefore, cannot use the relationship between suspended sediments concentration in surface and average suspended sediments concentration in section. When the Óbidos gauging station is analysed, it found there is a relationship between suspended sediments concentration in surface and average of fine suspended sediments concentration. It is observed too, that there is the relationship between coarse suspended sediments concentration and discharge. Therefore, it is possible to calculate of suspended sediments flux using these two relationships. The Amazon River export 1100 Mt year-1 of suspended sediments at Óbidos gauging station, of which 60% correspond at fine sediments flux and 40% to coarse sediments flux. It is observed that the suspended sediments are sensitivity of climate variability, generally El Niño events is associate with increase of fine suspended sediments and La Niña events increase a percentage of coarse sediments in Amazon River. It is using the turbidity for determinate of suspended sediments concentration, we use this technique due the high frequency in acquisition of data. However for use the turbidity is necessary the previous calibration. It was observed that the turbidity signal is an addition to the signal emitted by the particles in one sample and with this assumption the Rose model was used to separate the concentration signal obtained by the turbidity of the two types of sediments present in the Amazon River, fine particles and sand. Therefore, it was obtained the concentration profiles to fine sediments and the concentration profiles to the sand. It is observed during the rising period that the fine sediments profiles show a strong gradient, however in the flood periods this gradient reduce come a constant in all section. These results show that turbidity and Rouse model can be used for prediction of suspended concentration in Amazon River