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Confluences are places of complex interaction of flow and sediments coming from different channels. Studies at large confluences have advanced the understanding of these environments on a larger scale. This study is carried out at the confluence formed by the Paraná and Piquiri rivers in the state of Paraná - Brazil. It characterizes the morphology, flow structure and sediment dispersion for these two channels. The methodology consists of: interpoling bathymetric data; analyze the ADCP data – Acoustic Doppler Current Profiler and quantify the suspended and bottom sediments. ADCP data was processed in VMT software and generated the following information: flow direction, sediments load (bed and suspended) and also used to calculate the moment ratio (Mr), discharge ratio (Qr), flow power (Ω), and specific flow power (ꞷ) in both channels. The results reveal the variation of channel depth, and specific morphological areas for the confluence with a sediment accumulation zone, submerged lateal bar and excavation area. The flow dynamics shows an increase in velocity in the Paraná River downstream of the confluence, and a decrease in the flow velocity of the Piquiri River as it approaches the junction. The confluence has flow stagnation zone, acceleration and shear layer. The concentration of suspended sediment is higher in the Piquiri River, on the other hand the Paraná River presents thicker fractions of bed material.

The dynamics of suspended sediment production and transport in large rivers are essential geomorphologicalprocesses that can influence biodiversity. The aim of this work was to analyze the spatio-temporal variation of suspendedsediment transport in the lower Negro River using Sentinel-2 images. The suspended sediment concentration (SSC) wasestimated from the reflectance of band 4 of the MSI sensor onboard the Sentinel-2A and Sentinel-2B. The results indicate thatthe hydrological regime controls the temporal variability of SSC, being higher in the low water period and lower duringflooding, with a mean concentration of 5.28 mg L-1 for the period 2015–2019. Analysis of the spatial variation of SSC inSentinel-2 images indicated a zone of active sediment deposition located downstream of the islands of the AnavilhanasArchipelago. Geology, forest cover, and hydrological variability are the main factors controlling the low sediment yield of thebasin, with an estimated suspended solid flux of 5.76×106 ton∙year-1 and a specific yield of 8 ton∙km-2∙year-1. Despite the lowerquantity of images between February and April, due to high cloud cover, this study showed that Sentinel-2 images could beused to monitor the temporal and spatial dynamics of suspended sediment transport in Amazonian blackwater rivers.

Szatten Dawid. Ocena transportu rumowiska zawieszonego z wykorzystaniem nefelometrycznych i tradycyjnych pomiarów mętności wody na przykładzie kaskady dolnej Brdy = The estimation of suspended sediment transport using nefelometric and traditional measurements of turbidity of water on an example of the cascade lower Brda River. Journal of Education, Health and Sport. 2016;6(1):64-72. eISSN 2391-8306. DOI http://dx.doi.org/10.5281/zenodo.44629 http://ojs.ukw.edu.pl/index.php/johs/article/view/44629 http://pbn.nauka.gov.pl/works/692137 Formerly Journal of Health Sciences. ISSN 1429-9623 / 2300-665X. Archives 2011–2014http://journal.rsw.edu.pl/index.php/JHS/issue/archive The journal has had 7 points in Ministry of Science and Higher Education parametric evaluation. Part B item 755 (23.12.2015). 755 Journal of Education, Health and Sport (null) 2391-8306 7 © The Author (s) 2016; This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland and Radom University in Radom, Poland Open Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited. The authors declare that there is no conflict of interests regarding the publication of this paper. Received: 21.12.2015. Revised 25.12.2015. Accepted: 09.01.2016. Ocena transportu rumowiska zawieszonego z wykorzystaniem nefelometrycznych i tradycyjnych pomiarów mętności wody na przykładzie kaskady dolnej Brdy The estimation of suspended sediment transport using nefelometric and traditional measurements of turbidity of water on an example of the cascade lower Brda River Dawid Szatten Uniwersytet Kazimierza Wielkiego w Bydgoszczy, Wydział Kultury Fizycznej, Zdrowia i Turystyki, Instytut Geografii, 85-428 Bydgoszcz, ul. Mińska 15 Streszczenie Ocenę transportu rumowiska zawieszonego, dla zbiorników retencyjnych kaskady dolnej Brdy, przeprowadzono w celu porównania metod: tradycyjnej (wagowej) oraz nefelometrycznej (optycznej). Analizy dokonano na podstawie badań terenowych przeprowadzonych poniżej Zbiornika Smukała w latach 2014 - 2015. Obejmowały one pobór prób w celu oznaczenia wartości wskaźnika zawiesina ogólna (metoda tradycyjna) oraz nefelometrycznej mętności wód (metoda laserowa). Pobór połączony był z obserwacjami stanów wody, umożliwiając określenie sytuacji hydrologicznej. Zebrane dane zinterpretowano za pomocą podstawowych metod statystycznych. Stwierdzono, iż rzeka Brda charakteryzuje się niewielkim obciążeniem w materiał zawieszony. Obserwacje zmącenia wód, umożliwiły określenie chwilowej dynamiki zawiesin oraz wskazanie głównego źródła pochodzenia analizowanej składowej transportu fluwialnego. Otrzymane dane wskazują na możliwość zamiennego stosowania porównywanych w artykule metod. Abstract The evaluation of the suspended sediment transport was conducted on artificial reservoir of cascade of lower Brda River, to compare methods: traditional (weight) and nephelometric (optical). The analysis was based on field research conducted below the Smukała Reservoir in the years 2014 - 2015. These included sample collection for determining the value of total suspension (traditional method) and nephelometric turbidity of water (laser method). Sampling was connected with the observations of water levels, for specifying the hydrological situation. The collected data were interpreted using basic statistical methods. Was found that the the Brda River is characterized by a low suspended sediments load. Observations turbidity of water was possible to determine temporary dynamics of suspended sediments and indicate the main source of the suspended material. Received in article data indicate that the compare methods are interchangeability. Słowa kluczowe: transport rumowiska zawieszonego, mętność wód, zawiesina ogólna, nefelometryczne pomiary mętności, sztuczne zbiorniki wodne. Key words: suspended sediment transport, turbidity of water, total suspension, nefelometric measurements, artificial reservoir.

An aggregated model to estimate mean denudation rates of tropical mountain basins with limited data is presented, which is calibrated for Antioquia (Colombia); based on the transport equation of Engelund-Hansen. Two complementary approaches are purposed: (1) alluvial river reach model, dependent on discharge, slope and hydraulic geometry and (2) hillslope model dependent on discharge minus base flow, slope, drainage density and flow convergence degree. Both models are closed with a regression for the Shields parameter, depending on sediment yield (t/km2/yr) and an erodibility factor, which is considered robust due to the diversity of scale, morphology and weather of the 23 basins analyzed. Both model approaches predicts inside a +/- 50% margin of error the sediment yields of 70% of the basins, those with less peculiarities; correcting it with a bed load portion, additional to the suspended transport measured, analytically estimated and proved with field data.

Sediment yield is affected by many factors, such as climate, geology, geomorphology, land use and human activities. Sediment signatures are the statistic indices or curves that are able to effectively describe the temporal and spatial characteristics of sediment transport and evaluate the ability of the streamflow to deliver the sediment. In this study, the sediment signatures of Upper Sangamon River Basin, which is an intensively managed watershed for agriculture development, are analyzed. Firstly, a semi-distributed model of sediment transport is built up based on the Tsinghua Representative Elementary Watershed (THREW) model, and it is applied to Upper Sangamon River Basin. The result of sediment simulation is analyzed by four sediment signatures, i.e. specific sediment yield, sediment delivery ratio, cumulative sediment curve and effective discharge. The sediment signatures are consistent with each other and accord with the fact of the agricultural production in Upper Sangamon River Basin.

The research on the hydro-geomorphology, sediment transport and human impact of large rivers has recently increased in South America. The GLOCOPH (Global Commission on Continental Paleohydrology) Working Group on Large Rivers chaired by us, organized Symposiums and Field Conferences on key large fluvial systems since 1997 such as the Paraná (1997 and 2006), the Araguaia (1999) and the Amazon (2003). Presently, the activities of GLOCOPH are also linked to TERPO (Terrestrial Processes, Deposits and History) Program supported by the Commission of INQUA- Focus area group Hydrological change and climate. Additionally, joint efforts were made with the IGCP Project 518 Fluvial sequences as evidence for landscape and climatic evolution in the Late Cenozoic and two important meetings were organized in China and Brazil during 2006 when the Paraná River Field Conference, an activity related to the GLOCOPH International Symposium, was held at Guarulhos.

Las tendencias espaciales de los parámetros texturales (tamaño medio de grano, selección y asimetría) en Bahía Magdalena, Baja California Sur, México, se calcularon a partir de 58 estaciones de muestreo, con la finalidad de inferir la trayectoria de los vectores residuales de transporte de sedimentos. Los análisis de las tendencias espaciales y de componentes principales aplicados a los parámetros texturales indicaron que el sedimento, con una buena selección, está asociado con arenas finas a muy finas. Los vectores residuales de transporte sugieren la presencia de dos giros en la dispersión de material clástico: (1) giro ciclónico en la parte central y profunda, y (2) giro anticiclónico en la región sureste de la bahía. Las trayectorias de las partículas sedimentarias tienen una excelente correlación con las corrientes residuales de marea dentro de la Bahía Magdalena.The grain-size trend analysis (grain size, sorting asymmetry) was determined at 58 stations in order to infer the residual vectors of sediment transport in Magdalena Bay, Baja California Sur, Mexico. Grain-size trend analysis and principal components analysis were applied to textural sediment parameters. The results indicated that well-sorted sediment is associated with fine to very fine sand. The residual vector transport suggests the presence of two gyres in the dispersion of clastic material: (1) acycloneic gyre in the deeper, central part and (2) an acycloneic gyre in the southeast part of the bay. The sediment transport pattern is highly correlated with the residual tidal currents in Magdalena Bay.

La cuantificación del transporte sólido es muy importante en estudios de ingeniería y en el diseño de diques o puentes y, al mismo tiempo, es una operación muy difícil de realizar. El costo de las mediciones del transporte sólido es alto, sobretodo en pequeñas cuencas de montaña, y requiere además un monitoreo prolongado en el tiempo dada su extrema variabilidad. Este trabajo resume la cuantificación de la carga de transporte de materiales y la validación de diferentes modelos de transporte en una cuenca de montaña de 5,93 km² en el sur de Chile. Entre octubre 1997 y mayo 2005 la producción sólida total fue 7,1 * 10³ toneladas (tasa media de 171 ton/año/km²) con el 55,7% de sedimentos en suspensión. La producción de sedimentos en suspensión varió entre 17 y 1084 ton/año mientras que el transporte sólido de fondo fue entre 14 y 677 ton/año. Las fórmulas de transporte sólido aplicadas a un rango de caudales inferiores a 2,14 m³/s tienden a sobrestimar la producción de sedimentos, a excepción de los modelos de Van Rijn y Bathurst. Se sugiere el uso del modelo de Bathurst para estimar el transporte de sedimentos en cuencas sin información cercanas a la zona de estudio.The quantification of sediment transport is very important in engineering studies and in the design of dams and bridges, but at the same time is one of the most difficult tasks to undertake. Sediment transport monitoring is expensive especially in small mountain catchments, and requires long records to account for its very high variability. This study summarizes the quantification of sediment transport and the validation of different sediment transport models in a 5.93 km² catchment located in the Andes Mountains in Southern Chile. From October 1997 to May 2005, total sediment transport was 7.1 * 10³ tons (mean sediment transport rate of 171 ton/year/km²) in which suspended sediment participated with the 55.7%. Suspended sediment transport varied between 17 and 1084 ton/year while bedload ranged from 14 to 677 ton/year. For a range of discharges lower than 2.14 m³/s the different transport models overestimated sediment transport, the exception being those proposed by Van Rijn and Bathurst. The Bathurst model is proposed for sediment transport estimation in ungauged mountain catchments near the study area.

El estuario de Bahía Blanca, ubicado al sur de la provincia de Buenos Aires (Argentina), constituye una costa baja con extensas llanuras de marea, islas y una compleja red de canales de diferentes magnitudes. Estos últimos integran un sistema de canales interconectados. El objetivo de este trabajo es establecer la circulación sedimentaria como carga de fondo en un sistema de canales interconectados (Cabeza de Buey, El Alambre, La Lista y Principal) mediante el análisis de los rasgos morfológicos de fondo, utilizando métodos acústicos (ecosonda y sonar lateral). El canal Cabeza de Buey se comunica con el canal La Lista a través del canal El Alambre. Los dos primeros vierten sus aguas en el canal Principal. El canal Cabeza de Buey posee un lecho plano constituido por material pelítico con arena muy fina. En su tramo más interno se presentan dunas medianas compuestas por arena fina, con un perfil asimétrico según el reflujo. Estas formas, continúan su desarrollo ininterrumpidamente hacia el canal El Alambre, donde se originan dunas grandes (altura 1,5 m) formadas por arena muy fina. Sus crestas son sinuosas o barjanoides y poseen su talud hacia la corriente de bajante. En el canal La Lista se determinan dunas asimétricas medianas orientadas según el reflujo y grandes linea-ciones sedimentarias (sand ribbons) sobre un fondo consolidado. El sedimento movilizado por la corriente corresponde a la fracción limo-arena fina. La distribución y configuración de las geoformas evidencian que el transporte sedimentario como carga de fondo se concentra principalmente en el canal La Lista. Es así como en el sistema de canales estudiado, sólo un canal de marea regula la dispersión de arena, transportando un importante volumen hacia el canal de navegación.Bahia Blanca estuary located in the south of Buenos Aires province, Argentina, is characterized by a low coastal area with large tidal plains, islands, and a complex network of tidal channels of different dimensions. The latter form an interconnected tidal channel system. The aim of this study was to determine the net bed load sediment transport in an interconnected channel system (Cabeza de Buey, El Alambre, La Lista, and Principal channels) through an analysis of the morphological features of the bottom using acoustic data (echo sounder and side scan sonar). Cabeza de Buey channel is connected to La Lista channel through El Alambre channel. The first two flow into the Principal channel. Cabeza de Buey channel has a fiat bed of mud with very fine sand and medium-sized dunes of fine sand in its inner sector that display an asymmetrical section according to the ebb flow. These dunes continue to develop uninterrupted towards El Alambre channel, where large dunes (1.5 m high) of very fine sand originate. Their crest lines are either sinuous or barchanoid and they have their lee towards the ebb current In La Lista channel, medium-sized asymmetrical dunes and large sand ribbons form on a rocky bottom according to the ebb flow. The sediment mobilized by the currents is characterized by the fine sand - silt fraction. The distribution and configuration of bed forms reveal that the bed load sediment transport is mainly concentrated in La Lista channel. Thus, only one tidal channel regulates the dispersal of sandy material, transporting a significant volume of sediment towards the shipping channel.

The quantification of sediment transport is very important in engineering studies and in the design of dams and bridges, but at the same time is one of the most difficult tasks to undertake. Sediment transport monitoring is expensive especially in small mountain catchments, and requires long records to account for its very high variability. This study summarizes the quantification of sediment transport and the validation of different sediment transport models in a 5.93 km2 catchment located in the Andes Mountains in Southern Chile. From October 1997 to May 2005, total sediment transport was 7.1 * 103 tons (mean sediment transport rate of 171 ton/year/km2) in which suspended sediment participated with the 55.7%. Suspended sediment transport varied between 17 and 1084 ton/year while bedload ranged from 14 to 677 ton/year. For a range of discharges lower than 2.14 m3/s the different transport models overestimated sediment transport, the exception being those proposed by Van Rijn and Bathurst. The Bathurst model is proposed for sediment transport estimation in ungauged mountain catchments near the study area.

A two-dimensional, nonlinear, finite-difference, hydrodynamic/suspended-sediment transport coupled model was applied to the San Pedro tidal creek (Cadiz Bay, Spain) to study the characteristics of the principal tidal constituents (M2, S2, K1, and O1) and sediment transport. Results show a clear predominance of the semidiurnal tide, with more than 95% of the system’s total energy and related currents up to 1 m s–1 in some areas. Current velocity asymmetries, related to nonlinear interaction effects, are mainly flood-directed all along the creek except at the mouth, where they are influenced by morpho-bathymetric characteristics. In these areas, the local asymmetries are clearly correlated to the net transport of sediment through the creek’s course, which suggests the absence of morphodynamical balance in the present creek’s evolution after human interventions that have modified its natural configuration. Key words: San Pedro creek, numerical model, tidal hydrodynamics, sediment transport.

Most erosion models applied at basin scale are based on spatially aggregated representation, for example, in a space subdivision of the surfaces to which behavior is assumed homogeneous (sub-basins, hydrological units, etc.). This approach leads to a desirable simplification of the calculations, but presents difficulties in addressing problems related to sediment transport and identification of sediment source areas, which should be treated by a continuous spatial representation. Spatially distributed models, however, allow a more accurate approach to this problem, at the cost of an increased computational complexity. The objective of this work is the calibration and validation of the model WATEM/SEDEM, an empirical-conceptual spatially distributed model, to predict erosion and sediment yield in two watersheds in the Central Spanish Pyrenees: i) the watershed of the Barasona Reservoir (1504 km2), which is drained by the Ésera and Isábena Rivers, the model calibration and validation was based on the depositional history of the Barasona Reservoir and suspended sediment records over 3 years (May 2005–May 2008) at the outlet of the Isábena River; ii) the experimental Arnás catchment (2.84 km2), the model calibration was performed based on a dataset of soil redistribution rates derived from point 137Cs inventories, allowing capture differences per land use in the main model parameters. The validation process was carried with the registration of six years of suspended sediment at the outlet of the Arnás catchment. The calibration process for watershed of the Barasona Reservoir showed the problem you have when trying to calibrate the parameters of transport capacity with a single variable (the export of sediment to the basin outlet), making impossible to find a single set of parameters that optimize the error function, making it necessary to adopt a compromise solution. For the experimental Arnás catchment the model calibration processes using spatially distributed sediment yield derived from 137Cs inventories allowed calibrating the empirical parameters of transport capacity in a satisfactory way, finding a single combination of values that optimizes the error function. These results show that the calibration parameters of transport capacity are a fundamental aspect of the model WATEM/SEDEM and other similar models. To obtain a reliable estimate of the spatial distribution of erosion and sediment transport requires a calibration and validation by means of spatially distributed data of soil loss, which in turn allows a calibration of spatially distributed parameters concerning transport capacity

Runoff and sediment transport during the snowmelt period (May June, 2004) in the Izas catchment (Central Pyrenees) were studied to obtain a sediment balance and to assess the relative importance of sediment transport during that period. The results demonstrated the importance of the snowmelt period and showed that most sediment was exported in the form of solutes (76% of the total for the May-June time span); 24% was exported as suspended sediment and no bedload was recorded. Suspended sediment mostly occurred during the second phase of the snowmelt period, when an expanding area of the catchment was free of snow. Sediment transport during the snowmelt period represented 43% of the annual sediment yield.

Today, beaches are in a critical situation due to erosion. These places are very significant for the economy and tourism. For this reason is important to know the rate of sediment transport and the behavior of it. This work proposes a methodology based in used international models to estimate magnitude and direction of the littoral sediment transport. The method that expose propose to use Longuet-Higgins's velocity formula in Bijker's method to obtain cross shore distribution of alongshore sediment transport. Even, values in surf zone are required for this, it can solve through methodology shown in Coastal Engineering (2000) of Technical University of Delft. Calibration is make for two study.

Os objetivos do presente trabalho foram desenvolver rotina computacional para a solução da equação de Yalin e do diagrama de Shields e avaliar uma equação simplificada para modelar a capacidade de transporte de sedimento num Latossolo Vermelho Distrófico que possa ser utilizada no Water Erosion Prediction Project - WEPP, assim como em outros modelos de predição da erosão do solo. A capacidade de transporte de sedimento para o fluxo superficial foi representada como função-potência da tensão cisalhante, a qual revelou ser aproximação da equação de Yalin. Essa equação simplificada pôde ser aplicada em resultados experimentais oriundos de topografia complexa. A equação simplificada demonstrou acuracidade em relação à equação de Yalin, quando calibrada utilizando-se da tensão média cisalhante. Testes de validação com dados independentes demonstraram que a equação simplificada foi eficiente para estimar a capacidade de transporte de sedimento.The objectives of the present work were to develop a computational routine to solve Yalin equation and Shield diagram and to evaluate a simplified equation for modeling sediment transport capacity in a Dystrophic Hapludox that could be used in the Water Erosion Prediction Project - WEPP, as well as other soil erosion models. Sediment transport capacity for shallow overland flow was represented as a power function of the hydraulic shear stress and which showed to be an approximation to the Yalin equation for sediment transport capacity. The simplified equation for sediment transport could be applied to experimental data from a complex topography. The simplified equation accurately approximated the Yalin equation when calibrated using the mean hydraulic shear stress. Validation tests using independent data showed that the simplified equation had a good performance in predicting sediment transport capacity.

Soil management influences water erosion and sediment size in runoff. With the objective of quantifying sediments in runoff and their relation to runoff velocity (Rv), random roughness (RR), and Ir index, this experiment was carried out from 2003 to 2006, on a typical Hapludox with the following soil management systems submitted to chiseling: i) bare soil with plowing+two disking tillage (BSC); ii) plowing+two disking tillage (CTC); iii) no tillage with crop residues burned (BNTC); and iv) traditional notillage (TNTC). CTC, BNTC and TNTC treatments were cultivated with crop rotation and the BSC treatment was not cultivated. Five simulated rainfall tests were applied, with intensity of 64 mm h-1 and duration of 20, 30, 40, 50 and 60 min. RR was influenced by the residual effect of soil management and by simulated rainfall, and affected the Rv in the three initial rainfall tests. Sediments carried by runoff were influenced by soil management and by simulated rainfall. Most of the sediments were in the size range from 0.5 to > 2 mm, with a higher quantity of fine sediment in BNTC and TNTC treatments than in the other treatments. The D50 index of sediments changed with soil management system and with rainfall tests, decreasing with the increase of the RR and increasing with the increment of Rv and Ir index.O manejo do solo influencia a erosão hídrica e o tamanho de sedimentos na enxurrada. Com o objetivo de quantificar os sedimentos na enxurrada e relacioná-los com sua velocidade (Ve), com a rugosidade (RR) e com o índice Ir, conduziu-se este estudo entre 2003 e 2006, em um Nitossolo, sob sistemas de manejo do solo submetidos a uma escarificação: i) solo descoberto com aração e duas gradagens (SCE); ii) aração e duas gradagens (PCE); iii) semeadura direta em solo nunca preparado e com resíduos queimados (SQE); e iv) semeadura direta tradicional (STE). Os tratamentos PCE, SQE e STE foram cultivados com rotação de culturas e o SCE não foi cultivado. Foram aplicados cinco testes de chuva simulada, com intensidade constante de 64 mm h-1 e durações de 20, 30, 40, 50 e 60 minutos cada um. A RR foi influenciada pelo efeito residual do manejo do solo e pelas chuvas simuladas e afetou a Ve nos três testes iniciais de chuva. Os sedimentos transportados pela enxurrada foram influenciados pelo manejo do solo e pelas chuvas simuladas; tais sedimentos ocorreram em maior quantidade no tamanho entre 0,5 e > 2 mm do que nos tamanhos menores, com maior quantidade de sedimentos menores nos tratamentos SQE e STE do que nos demais tratamentos. O índice D50 dos sedimentos variou com o manejo do solo e com os testes de chuva, diminuindo com o incremento de RR e aumentando com o incremento de Ve de Ir.

La determinación de los aportes anuales de sedimentos en cuencas montañosas, es de suma importancia para el manejo de los recursos hídricos, así como para el diseño de obras hidráulicas. Los estimados de la producción de sedimentos se basan usualmente en considerar primordialmente los aportes de material fino (sedimentos suspendidos) despreciando, o asignándoles un porcentaje a los aportes de material grueso que son transportado como carga de fondo. El objetivo de este trabajo es el desarrollo de una metodología para estimar la producción total de sedimentos (arrastre suspendido y arrastre de fondo) en cuencas de montaña. Se calculan por separado la erosión laminar en las laderas empleando el modelo MUSLE para el acarreo en suspensión, y las ecuaciones de Schoklitsh y Meyer-Peter/Müller para el acarreo de fondo. Se aplican estos modelos a los hidrogramas de eventos extraordinarios de 10, 25, 50 100 y 500 años de periodo de retorno, para así obtener una relación funcional entre la producción de sedimentos por erosión laminar y la producción por arrastre de fondo, que permite mediante un modelo continuo lluvia-escorrentía estimar la producción media mensual y anual de sedimentos. La metodología se ilustra con una aplicación a las cuencas de la vertiente sur del Parque Nacional El Ávila en Caracas, Venezuela.The determination of the sediment yield in mountain basins is an important task in water resources management, and also in the design of hydraulic works. The estimates of sediment yield are usually obtained by considering mainly the suspended sediment, neglecting or assigning a proportion to the material that is transported as bed load. The paper’s objective is the development of a methodology to estimate the total sediment yield (suspended and bed loads) in mountain streams. Watershed laminar erosion is computed by using the MUSLE model, in order to estimate suspended sediment load. Bed load is calculated by applying the equations of Schoklitsh and Meyer-Peter/Müller. These models are applied using extraordinary events hydrographs, associated with storms of 10, 25, 50 100 and 500 years of return period, in order to obtain a functional relationship between the sediment yield due to laminar erosion and bed load. This relationship allows the estimation of monthly and annual series of total sediment yield, by using a continuous rainfall-runoff model. The methodology is applied on several watersheds located on the Southern slope of El Ávila National Park, in Caracas, Venezuela.

The determination of the sediment yield in mountain basins is an important task in water resources management, and also in the design of hydraulic works. The estimates of sediment yield are usually obtained by considering mainly the suspended sediment, neglecting or assigning a proportion to the material that is transported as bed load. The paper's objective is the development of a methodology to estimate the total sediment yield (suspended and bed loads) in mountain streams. Watershed laminar erosion is computed by using the MUSLE model, in order to estimate suspended sediment load. Bed load is calculated by applying the equations of Schoklitsh and Meyer-Peter/Müller. These models are applied using extraordinary events hydrographs, associated with storms of 10, 25, 50 100 and 500 years of return period, in order to obtain a functional relationship between the sediment yield due to laminar erosion and bed load. This relationship allows the estimation of monthly and annual series of total sediment yield, by using a continuous rainfall-runoff model. The methodology is applied on several watersheds located on the Southern slope of El ívila National Park, in Caracas, Venezuela.

With an area close to 377,000 km2 and a mean annual discharge of ~ 6,420 m3 s-1 the Araguaia River is the main river draining the central highlands of Brazil. The Araguaia Rivers is a particularly sandy anabranching system that has been suffering geomorphologic and sedimentary changes because of the effect of high rates of deforestation during the last decades. Little is known, however, on the amount of wash load transport. We will present the first relatively systematic results on wash load transport for the Araguaia River at the Aruanã gauge station. The drainage area at Aruanã is 77,000 km2 and the mean annual discharge is ~1,200 m3 s-1. A total of 140 samples from 20 field surveys were analyzed and the wash load transport was estimated. We calculated that from 2001-2007 the average annual transport oscillated between 8 Mt yr-1 and 6 Mt yr-1. An interesting aspect that makes the Araguaia unique when compared to other large alluvial rivers of Brazil is the relation between sandy load and wash load. The Araguaia at Aruanã carries up to ~57% of the total sediment load as sandy load. We can now conclude that wash load just represents near 43 to 49% of the total sediment load in this system. Our results demonstrate that previous works overestimated the total wash load transported by the Araguaia. Taking into account that these are the first systematic results on wash load transport in the Araguaia, proposed human interventions in this system affecting sediment flows such as dams can be extremely harmful for the fluvial system. A more systematic analysis of sediment transport and an integrated and multidisciplinary plan of basin management must be done so that the detrimental effects of these human interventions will be understood.

The confluence of the Paraná and Paranapanema Rivers is studied according to morphology and dynamics. It is probably the only example of this type of fluvial environment involving a large, tropical and intensive regulated river. Confluence channels were monitored along a hydrological cycle (high-low water level) in terms of morphology, flow velocity, magnitude, structure, and bedload dynamics. In this case, hydrology is controlled by the flow of the tributary, which develops a continuous and well-defined thalweg since the collector channel (a secondary channel of the Paraná River) that presents relatively large bedforms that reduce stream power by increasing roughness. Although significant differences in channel morphology were not observed along the hydrological year, bed material texture indicates that the channel bottom is suffering a slight armoring process. This is probably the reason for the large asymmetry of channel confluence where the depth of the tributary channel is larger than that of the main collector channel (the Paraná left branch). The Rosana Dam, closed in 1987 and located 26 km upstream from the confluence, is the cause of the changes in sediment transport and the generation of the channel pavement. With the closing of the Porto Primavera Dam (2000) in the Paraná River (27 km upstream from the confluence) a new morphodynamics is foreseen for this environment, and this paper can be seen a relevant pioneer reference for environmental monitoring and management.

This paper summarises twelve years of research undertaken on the lower River Ebro (NE Spain). The research has been undertaken to achieve a fundamental understanding of the fluvial processes in this large Mediterranean river affected by flow regulation. Dams in the whole basin and, in particular, in the lower section of the river alter the Ebro’s flow and sedimentary regimes, thus affecting its physical and ecological functioning. Data obtained on hydrology, sediment transport and river channel dynamics (i.e. particle mobility, bed structure) have aided the design and implementation of flushing flows since 2002; the main objectives of these artificial releases were the control of excess growth of aquatic vegetation (i.e. macrophytes) and the maintenance of certain sedimentary activity in the channel downstream from the Mequinenza-Ribarroja-Flix Dam complex. Results highlight the sedimentary disequilibrium of the river, with the current sediment load equating to 1% of that estimated at the beginning of the 20th century in the absence of dams and under different land uses. Channel platform changes show that the channel has become more stable since dams were closed and a significant reduction of sediment availability has occurred, together reinforcing the sedimentary disequilibrium of the river. Monitoring of flushing flows has demonstrated their high sediment transport capacity. This suggests that, in combination with other restoration measures such as sediment injections, flushing flows could greatly benefit the riverine ecosystem, reducing macrophyte stands and maximizing the sediment delivery to the lowermost river reaches.

The Pantanal wetland is a complex landscape with distinct hydrogeomorphic compartments, with singular and hydrosedimentary processes. Examining these processes draws great interest in understanding Pantanal dynamics for both the management of the system and the geological record predicted by facies models. Hydrosedimentary data in the Pantanal remain scarce, in spite of government efforts to improve and increase data collection in the Upper Paraguay Basin. This study aims to enhance the understanding of active hydrosedimentary processes in the Pantanal Paraguay trunk-river system in the Corumbá reach. Hydrosedimentary surveys were accomplished in the main channel and tributaries of the Paraguay River. These surveys helped characterize the hydrosedimentary dynamics to consider the active sedimentary processes in this reach. The Paraguay River interacts complexly with its floodplain, which functions as a reservoir retaining flood water and disturbing river discharge. Bathymetric surveying showed that Paraguay River channel has longitudinal compound bar bedforms built by superimposition of ripples. The backwater effect, possibly related with both hydrological regime and geomorphological characteristics of the area, was detected by means of rating-curve analysis of the gauge stations. This effect is hydrologically produced by the out-of-phase flood pulse of the Pantanal and geomorphically driven by the hydraulic bottleneck of the Urucum and Bodoquena massifs. Both factors possibly occur simultaneously. The hydrogeomorphic characteristics (morphology, river competence, and stream power) of the Paraguay River denote that the elaboration of models more appropriate to the Pantanal context is needed.

The Immerse Boundary Method (IBM) was used to evaluate the sediment transport over deformable beds. Large Eddy Simulation (LES) procedures were used for the mathematical treatment of turbulence, and the advection-diffusion equation was used to calculate sediment concentration. The Finite Differences Method with staggered grid was applied for the numerical solution of the governing equations (filtered Navier-Stokes, Continuity and advection-diffusion equations). Spatial derivatives were discretized using second order centered differences. A second order explicit Adams-Bashforth scheme was used for the time evolution in the advection-diffusion equation, while a fourth order Adams-Bashforth scheme was used for the filtered Navier-Stokes equations. The numerical simulation reproduced flow structures like large eddies after the dune crests and counter-rotative vortices, which are important in sediment transport. Resuspension fluxes and sedimentation (dependent on particle concentration) were calculated using equations proposed in this study. The deformations of the bed caused by erosion and deposition may be well followed through the present procedures, showing that this methodology is adequate to evaluate bed modifications and sediment transport in alluvial flows.Se utilizó el método de fronteras inmersas para evaluar el transporte de sedimentos en lechos deformables. Los procedimientos de la simulación de gran escala fueron utilizados para el tratamiento matemático de la turbulencia, y se utilizó la ecuación de advección-difusión para calcular la concentración de sedimentos. Se aplicó el método de diferencias finitas con malla desplazada para la solución numérica de las ecuaciones básicas (Navier-Stokes filtrado, continuidad y las ecuaciones de advección-difusión). Las derivadas espaciales fueron discretizadas mediante diferencias de segundo orden centrado. Se utilizó un esquema explícito de Adams-Bashforth de segundo orden para la evolución del tiempo en la ecuación de advección-difusión, mientras que un esquema Adams-Bashforth de cuarto orden fue utilizado para las ecuaciones de Navier-Stokes filtrado. La simulación numérica reproduce estructuras de flujo, como los remolinos grandes después de las crestas de las dunas y los vórtices contrarrotativos, que son importantes en el transporte de sedimentos. Los flujos de resuspensión y sedimentación (dependientes de la concentración de partículas) se calcularon utilizando las ecuaciones propuestas en este estudio. Las deformaciones del lecho por la erosión y la deposición pueden ser bien seguidas a través de los procedimientos aquí presentados, que muestran que esta metodología es adecuada para evaluar las modificaciones del lecho y el transporte de sedimentos en los flujos aluviales.

En este artículo se presenta una propuesta metodológica para hacer el análisis de morfología fluvial y transporte de sedimentos para cuencas altamente intervenidas por la acción humana. En dicha metodología se proponen diferentes actividades las cuales permitirán hacer un análisis detallado de la morfología fluvial y los sedimentos en una cuenca. Entre las etapas que se proponen para implementar esta metodología se tienen: análisis en planta de la cuenca, análisis de los perfiles altimétricos de las principales corrientes, levantamiento de información en campo (aforos líquidos, sólidos y observaciones generales de la morfología de la cuenca) y estimación de la carga y capacidad de carga de sedimentos en la quebrada principal. Una aplicación a la cuenca de la quebrada Doña María (en el Área Metropolitana del Valle de Aburrá, Colombia) es presentada.This paper shows a methodological proposal to carry out river morphology analysis and sediment transport for urban basins highly intervened by human actions. In this methodology, different activities that will allow doing a detailed analysis for the river morphology and sediment transport in the basin are proposed. Among the steps proposed to implement this methodology, there are: analysis in plant of little basin, altitude profiles analysis of the main sub-basins, field measures (measures of liquid and solid discharge and general observations of the basin morphology), and estimations of sediments load and bed load capacity in the stream. An application to basin of Doña María is showed.