scholarly journals Balance sedimentario del embalse de Ribarroja

2021 ◽  
Author(s):  
A. Tena ◽  
D. Vericat ◽  
R.J. Batalla
Keyword(s):  
Suspended Sediment ◽  
Sediment Load ◽  
Land Use Changes ◽  
Suspended Sediment Transport ◽  
Suspended Sediment Load ◽  
Lower Reach ◽  
Iberian Range ◽  
Intermittent Rivers ◽  
Sediment Transfer

The aim of this study was to build up a sediment budget of the Ribarroja Reservoir, which is located in the lower reach of the River Ebro. For this purpose, we analysed continuous discharge and suspended sediment transport data at several river sections entering the reservoir and at the dam outlet, for the period 2008-2011. The sediment load estimated upstream of the Mequinenza reservoir was 0.66×106 t a-1, whereas the estimated output was 0.04×106 t a-1. The sediment input coming from the large but highly regulated Pyrenean tributaries (Segre and Cinca) was 0.16×106 t a-1, whereas intermittent rivers naturally flowing from the Iberian Range (Matarraña and Algars) supplied an average load of 760 t a-1. The suspended sediment load trapped in the Mequinenza and Ribarroja reservoirs for the study period was estimated at 0.78×106 t a-1, which implies a reduction of ca. 95% of the sediment load of the river. The results illustrate the role of reservoirs in interrupting the sediment transfer in the lower reach of the Ebro, within a context of structural sediment deficit, following widespread land use changes (afforestation) that took place in the catchment after the 1940s.

scholarly journals Geomorphological factors influencing hysteresis patterns between suspended load and flow rate in Alpine rivers

2018 ◽  
Vol 40 ◽  
pp. 04004
Author(s):  
Clément Misset ◽  
Alain Recking ◽  
Cédric Legout ◽  
Alain Poirel ◽  
Marine Cazilhac
Keyword(s):  
Time Series ◽  
Suspended Sediment ◽  
Sediment Load ◽  
Hysteresis Loops ◽  
Total Solid ◽  
Suspended Load ◽  
Suspended Sediment Transport ◽  
Suspended Sediment Load ◽  
Fine Sediments ◽  
Erosion Processes

Suspended sediment load represents a large part of total solid fluxes transported in most rivers. Thus, for hydropower plan management or for environmental issues, it is crucial to understand how these sediments are produced, stored and transported in a given catchment. Hysteresis loops in discharge-suspended load signals are commonly used to assess sediment sources and production processes but most of the time the shape of this relation is analyzed qualitatively on short time series or for few events. In this study we analyzed quantitatively 10 long time series of suspended sediment load of various alpine catchments. This method allows us to compare events and to assess to which extent fine sediments originate from hillslope erosion processes or from river bed remobilization. We found that watersheds with braided bed morphology are dominated by clockwise loops while those with narrower bed as step-pool morphology are dominated by counter-clockwise hysteresis or have no general trend. These results suggest that storage and remobilization of fine sediments within the bed could play a major role in suspended sediment transport in Alpine streams, especially in large braided rivers.

Spatial and temporal variations of suspended sediment responses from the subtropical Richmond River catchment, NSW, Australia

Soil Research ◽  
2002 ◽  
Vol 40 (3) ◽  
pp. 419 ◽  
Author(s):  
Shahadat Hossain ◽  
Bradley Eyre ◽  
David McConchie
Keyword(s):  
Suspended Sediment ◽  
Sediment Load ◽  
Land Use Changes ◽  
Suspended Sediments ◽  
Temporal Variations ◽  
Suspended Sediment Load ◽  
Flood Events ◽  
River Catchment ◽  
Forest Coverage ◽  
Dry Seasons

Suspended sediment exports from the Richmond River catchment were examined during 2 hydrological years (1994–96). On a yearly basis, the Richmond River catchment produced <2% suspended sediment load during dry seasons, whereas about 75–91% of the yearly suspended sediments were exported during floods which occurred <5% of the year. Annual suspended sediment exports from the Richmond River catchment varied more than 7-fold from dry year to wet year. Among the 3 major subcatchments, Richmond and Wilsons River subcatchments generated >93% of the suspended sediment load, while sediment exports from the Bungawalbin Creek subcatchment always remained low due to its flat topography and extensive forest coverage. Suspended sediment hysteresis patterns exhibited a clockwise response for 2 steep and less forested subcatchments and an anti-clockwise response for relatively low gradient and more forested subcatchment during all flood events. Land use changes in the Richmond River subcatchments indicate a possible increase of suspended sediment load of about 6-fold from their pristine condition.

scholarly journals Sub-Bankfull Flow Frequency versus Magnitude of Flood Events in Outlining Effective Discharges. Case Study: Trotuș River (Romania)

2018 ◽  
Author(s):  
Dan Dumitriu
Keyword(s):  
Suspended Sediment ◽  
Sediment Load ◽  
Temporal Variations ◽  
Data Series ◽  
Suspended Sediment Transport ◽  
Suspended Sediment Load ◽  
Flood Events ◽  
Effective Discharge ◽  
Bankfull Discharge

Effective discharge, which represents the flow, or range of flows, that transport the most sediment over long term, was determined based on the mean daily flow discharge and mean daily suspended sediment discharge recorded between 1994 and 2014 at four gauging stations along the Trotuș River. This study proposes an efficient method for the estimation of effective discharge based on observed values of the suspended sediment load. By employing this method the suspended sediment load is no longer either under- or overestimated as in the cases when the assessment is based on sediment rating curves. The assessment on effective discharge was performed at two distinct levels: for the entire data series during the investigated time spans and, subsequently, for flows less than the bankfull discharge. The effectiveness curves of the suspended sediment transport characteristics revealed highly multimodal characteristics with many peaks, indicating ample ranges for the effective discharges. The main effective discharge corresponded to large flood events, which are typical for the upper end of the discharge range, whereas the secondary effective discharges corresponded to sub-bankfull flows, which are more frequent. The changes that occurred in the channel bed are reflected by the temporal variations in the effective discharge.

scholarly journals Sub-Bankfull Flow Frequency versus Magnitude of Flood Events in Outlining Effective Discharges. Case Study: Trotuș River (Romania)

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1292 ◽  
Author(s):  
Dan Dumitriu
Keyword(s):  
Suspended Sediment ◽  
Sediment Load ◽  
Temporal Variations ◽  
Data Series ◽  
Suspended Sediment Transport ◽  
Suspended Sediment Load ◽  
Flood Events ◽  
Effective Discharge ◽  
Bankfull Discharge

Effective discharge, which represents the flow, or range of flows, that transport the most sediment over the long-term, was determined based on the mean daily flow discharge and mean daily suspended sediment discharge recorded between 1994 and 2014 at four gauging stations along the Trotuș River. This study proposes an efficient method for the estimation of effective discharge based on observed values of the suspended sediment load. By employing this method the suspended sediment load is no longer either under- or overestimated as in the cases when the assessment is based on sediment rating curves. The assessment on effective discharge was performed at two distinct levels: for the entire data series during the investigated time spans and, subsequently, for flows less than the bankfull discharge. The effectiveness curves of the suspended sediment transport characteristics revealed highly multimodal characteristics with many peaks, indicating ample ranges for the effective discharges. The main effective discharge corresponded to large flood events, which are typical for the upper end of the discharge range, whereas the secondary effective discharges corresponded to sub-bankfull flows, which are more frequent. The changes that occurred in the channel bed are reflected by the temporal variations in the effective discharge.

Understanding watershed suspended sediment transport

2008 ◽  
Vol 32 (3) ◽  
pp. 243-263 ◽  
Author(s):  
Peng Gao
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Sediment Load ◽  
Transport Processes ◽  
Suspended Sediment Transport ◽  
Suspended Sediment Load ◽  
Watershed Scale ◽  
Rating Curve ◽  
Sediment Rating Curve ◽  
Sediment Monitoring

Suspended sediment at the watershed scale has played a critical role in sediment pollution, water-quality degradation, and the impairment of riparian ecosystems, and thus has been widely studied in many disciplines. This paper synthesizes a variety of methods adopted in suspended sediment monitoring, estimation and modelling for understanding sediment transport processes and determining the suspended sediment load. Methods for sediment monitoring are described in terms of direct and indirect approaches. Estimation of suspended sediment load is commonly achieved by establishing a sediment rating curve. Different approaches toward the establishment of a sediment rating curve are examined thoroughly. Techniques of sediment modelling are summarized via depiction of various hydrological and sediment models at the watershed scale. The paper ends with the discussion of future developments in suspended sediment studies at the watershed scale.

scholarly journals Land-Use/-Cover Changes and Their Effect on Soil Erosion and River Suspended Sediment Load in Different Landscape Zones of European Russia during 1970–2017

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1631
Author(s):  
Artyom V. Gusarov
Keyword(s):  
Soviet Union ◽  
Suspended Sediment ◽  
Sediment Load ◽  
Gully Erosion ◽  
European Russia ◽  
Relative Reduction ◽  
Forest Steppe ◽  
Suspended Sediment Load ◽  
Cultivated Land ◽  
Study Region

Contemporary trends in cultivated land and their influence on soil/gully erosion and river suspended sediment load were analyzed by various landscape zones within the most populated and agriculturally developed part of European Russia, covering 2,222,390 km2. Based on official statistics from the Russian Federation and the former Soviet Union, this study showed that after the collapse of the Soviet Union in 1991, there was a steady downward trend in cultivated land throughout the study region. From 1970–1987 to 2005–2017, the region lost about 39% of its croplands. Moreover, the most significant relative reduction in cultivated land was noted in the forest zone (south taiga, mixed and broadleaf forests) and the dry steppes and the semi-desert of the Caspian Lowland—about 53% and 65%, respectively. These territories are with climatically risky agriculture and less fertile soils. There was also a widespread reduction in agricultural machinery on croplands and livestock on pastures of the region. A decrease in soil/gully erosion rates over the past decades was also revealed based on state hydrological monitoring data on river suspended sediment load as one of the indicators of the temporal variability of erosion intensity in river basins and the published results of some field research in various parts of the studied landscape zones. The most significant reduction in the intensity of erosion and the load of river suspended sediment was found in European Russia’s forest-steppe zone. This was presumably due to a favorable combination of the above changes in land cover/use and climate change.

scholarly journals Prediction of daily suspended sediment load (SSL) using new optimization algorithms and soft computing models

2021 ◽  
Author(s):  
Hamid Darabi ◽  
Sedigheh Mohamadi ◽  
Zahra Karimidastenaei ◽  
Ozgur Kisi ◽  
Mohammad Ehteram ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Soft Computing ◽  
Sediment Load ◽  
Optimization Algorithms ◽  
Training Phase ◽  
Suspended Sediment Load ◽  
Engineering Structures ◽  
Northern Iran ◽  
Taylor Diagram ◽  
Computing Models

AbstractAccurate modeling and prediction of suspended sediment load (SSL) in rivers have an important role in environmental science and design of engineering structures and are vital for watershed management. Since different parameters such as rainfall, temperature, and discharge with the different lag times have significant effects on the SSL, quantifying and understanding nonlinear interactions of the sediment dynamics has always been a challenge. In this study, three soft computing models (multilayer perceptron (MLP), adaptive neuro-fuzzy system (ANFIS), and radial basis function neural network (RBFNN)) were used to predict daily SSL. Four optimization algorithms (sine–cosine algorithm (SCA), particle swarm optimization (PSO), firefly algorithm (FFA), and bat algorithm (BA)) were used to improve the capability of SSL prediction of the models. Data from gauging stations at the mouth of the Kasilian and Talar rivers in northern Iran were used in the analysis. The selection of input combinations for the models was based on principal component analysis (PCA). Uncertainty in sequential uncertainty fitting (SUFI-2) and performance indicators were used to assess the potential of models. Taylor diagrams were used to visualize the match between model output and observed values. Assessment of daily SSL predictions for Talar station revealed that ANFIS-SCA yielded the best results (RMSE (root mean square error): 934.2 ton/day, MAE (mean absolute error): 912.2 ton/day, NSE (Nash–Sutcliffe efficiency): 0.93, PBIAS: 0.12). ANFIS-SCA also yielded the best results for Kasilian station (RMSE: 1412.10 ton/day, MAE: 1403.4 ton/day, NSE: 0.92, PBIAS: 0.14). The Taylor diagram confirmed that ANFIS-SCA achieved the best match between observed and predicted values for various hydraulic and hydrological parameters at both Talar and Kasilian stations. Further, the models were tested in Eagel Creek Basin, Indiana state, USA. The results indicated that the ANFIS-SCA model reduced RMSE by 15% and 21% compared to the MLP-SCA and RBFNN-SCA models in the training phase. Comparing models performance indicated that the ANFIS-SCA model could decrease MAE error compared to ANFIS-BA, ANFIS-PSO, ANFIS-FFA, and ANFIS models by 18%, 32%, 37%, and 49% in the training phase, respectively. The results indicated that the integration of optimization algorithms and soft computing models can improve the ability of models for predicting SSL. Additionally, the hybridization of soft computing models with optimization algorithms can decrease the uncertainty of models.

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