Scale-breaks of suspended sediment rating in large rivers in Germany induced by organic matter

Abstract. Understanding the dynamics of suspended sediment and associated nutrients is of major relevance for sustainable sediment management aiming to achieve healthy river systems. Sediment rating curves are frequently used to analyze the dynamics of suspended sediments and their potential sources and sinks. Here we are using more than 750 000 measurements of the suspended sediment concentrations (SSC) and discharge at 62 gauging stations along 19 waterways in Germany based on the suspended sediment monitoring network of the German water and shipping authority, which started in the 1960ties. Furthermore, we analyse more than 2000 measurements of the loss on ignition (LOI) of suspended matter at two stations along the rivers Moselle and Rhine to asses the mineral and organic fraction of the suspended matter. SSC and LOI are analysed in terms of the power law rating to identify discharge depended process regimes of suspended matter. Our results indicate that for most studied gauging stations, rating coefficients are not constant over the full discharge range, but there is a distinct break in the sediment rating curve, with specific SSC-Q domains above and below this break. The transition of the rating exponent is likely to be a result of a change of controlling factors of the suspended sediment from intrinsic organic matter formation at low flows to extrinsic sediment supply (including mineral and organic fractions) due to hillslope erosion at high flows. Based on these findings we developed a conceptual rating model separating the mineral and organic fraction of the suspended matter in the Germany waterways. This model allows evaluating the sources of the mineral and organic fraction of the suspended matter and gain new insights into the first order control of discharge dynamics of suspended sediments.

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Scale breaks of suspended sediment rating in large rivers in Germany induced by organic matter

Earth Surface Dynamics ◽

10.5194/esurf-8-661-2020 ◽

2020 ◽

Vol 8 (3) ◽

pp. 661-678

Author(s):

Thomas O. Hoffmann ◽

Yannik Baulig ◽

Helmut Fischer ◽

Jan Blöthe

Keyword(s):

Organic Matter ◽

Suspended Sediment ◽

Suspended Matter ◽

Monitoring Network ◽

Suspended Sediments ◽

Low Flow ◽

Rating Curve ◽

Organic Fraction ◽

Sediment Rating Curve ◽

Aquatic Biomass

Abstract. Understanding the transport of suspended sediment and associated nutrients is of major relevance for sustainable sediment management aiming to achieve healthy river systems. Sediment rating curves are frequently used to analyze the suspended sediments and their potential sources and sinks. Here we use more than 750 000 measurements of suspended sediment concentrations (SSCs) and discharge (Q) collected at 62 gauging stations along 19 waterways in Germany based on the suspended sediment monitoring network of the German water and shipping authority, which started in the 1960s. Furthermore, we analyze more than 2000 measurements of the loss on ignition (LOI) of suspended matter at two stations along the rivers Moselle and Rhine to provide a proxy for the relative contributions of mineral load and organic matter. SSC and LOI are analyzed in terms of the power-law rating curve to identify discharge-dependent controls of suspended matter. Our results indicate that for most studied gauging stations, rating coefficients are not constant over the full discharge range, but there is a distinct break in the sediment rating curve, with specific SSC–Q domains above and below this break. The transition of the rating exponent likely results from increased supply of mineral suspended sediments from hillslope erosion at high flow and a shift of the organic matter sources from aquatic biomass-derived organic matter (i.e., high % LOI) at low flow, to mineral-associated organic matter with low % LOI eroded from hillslopes at higher flow. Based on these findings we developed a conceptual rating model for large (>10 000 km2) and low-turbidity (SSC < 1000 mg L−1) rivers separating the mineral and organic fraction of the suspended matter in German waterways. This model allows evaluating the sources of the mineral and organic fraction of the suspended matter and facilitates new insights into the first-order control of discharge on the quality and quantity of suspended sediments.

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Curvas-chave de descargas de sedimentos em suspensão no Baixo São Francisco

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v13.3.p1248-1262 ◽

2020 ◽

Vol 13 (3) ◽

pp. 1248 ◽

Cited By ~ 1

Author(s):

Solange Cavalcanti de Melo ◽

José Coelho de Araújo Filho ◽

Renata Maria Caminha Mendes de Oliveira Carvalho

Keyword(s):

Suspended Sediment ◽

Suspended Sediment Concentration ◽

Suspended Sediments ◽

Sediment Concentration ◽

Gradual Reduction ◽

Sao Francisco River ◽

Sediment Loads ◽

São Francisco River ◽

Historical Series ◽

Suspended Sediment Concentrations

RESUMOO conhecimento da análise quantitativa das concentrações de sedimentos em suspensão transportados pelo rio São Francisco bem como sua relação com as vazões é de muita importância, pois pode auxiliar na identificação dos efeitos da intervenção humana e ou ocasionados pelas condições naturais da região. As regiões a jusante dos barramentos no rio São Francisco apresentam como principal consequência a regularização das vazões e a diminuição das concentrações de sedimentos. O objetivo da pesquisa foi determinar as curvas-chave de sedimentos em suspensão (CCS) nas estações fluviométricas instaladas no Baixo São Francisco (BSF) após a barragem de Xingó. Para o estabelecimento dessas curvas foram utilizados dados de vazão e concentração de sedimentos em suspensão, obtidos do sistema Hidroweb no site da Agência Nacional da Água (ANA) no período de 1999 a 2018. Foram obtidas CCS para todo o trecho do BSF as quais apresentaram bons coeficientes de determinação. Na análise dos dados também foi possível perceber que nos últimos anos, desde 2013 houve redução gradativa das vazões disponibilizadas na barragem de Xingó. Consequentemente, houve também a redução gradativa das cargas de sedimentos em suspensão geradas nas estações de Piranhas, Traipu e Propriá, ou seja, os menores valores já registrados no BSF correspondendo as menores séries históricas tanto de vazão como de sedimentos em suspensão. Keys curves of sediment discharges in suspension in the Lower São Francisco A B S T R A C TThe knowledge of the quantitative analysis of suspended sediment concentrations carried by the São Francisco River as well as its relation with the flows is of great importance, since it can help in the identification of the effects of human intervention and/or caused by the natural conditions of the region. In the downstream regions of the São Francisco riverbanks, the main consequence was the regularization of flow rates and the reduction of sediment concentrations. The objective of the research was to determine the key curves of suspended sediments (CCS) at the fluviometric stations installed in the lower São Francisco river after Xingó dam. For the evaluation, flow data and suspended sediment concentration were used. These data were obtained from the Hidroweb system on the website of the National Water Agency (ANA) from 1999 to 2018. CCS were plotted for all stretches and presented good coefficients of determination (R2). Based on the analysis of the data it was also possible to notice that in recent years, since 2013 there has been a gradual reduction of the flows available in the Xingó dam. Consequently, there was also a gradual reduction of suspended sediment loads generated at the Piranhas, Traipu and Propriá stations, that is, the lowest values already recorded in lower São Francisco, corresponding to the lower historical series of both discharge and suspended sediments.Keywords: dam, flow, sediments

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Impact of Chelicorophium curvispinum on the concentration-discharge response of suspended sediment in the Rhine River

10.5194/egusphere-egu21-9199 ◽

2021 ◽

Author(s):

Marcel van der Perk

Keyword(s):

Suspended Sediment ◽

Suspended Sediment Concentration ◽

Sediment Concentration ◽

Sudden Increase ◽

Rhine River ◽

Rating Curve ◽

Independent Evidence ◽

Sediment Rating Curve ◽

Suspended Sediment Concentrations

In an ongoing study to the decline in suspended sediment concentrations and loads in the Rhine river since the mid-1950s, the temporal changes in the power-law sediment rating curve parameters were examined. This revealed that the rating exponent of the rating curve increased substantially between the early and late 1980s. Until the early 1980s, the ratings curves were relatively flat with values of the rating exponent b varying around 0.2. In the mid-1980s, the exponent suddenly increased to a value between 0.4 and 0.6 and since then has remained within this range. This change in the rating exponent was mainly caused by a decrease in suspended sediment concentrations during low discharges. During high discharges, the suspended sediment concentration initially increased during the late 1980s, but this increase was nullified soon afterwards due to the declining trend in suspended sediment concentration.The sudden increase of the rating exponent coincided with the period that the Ponto-Caspian Chelicorophium curvispinum (Caspian mud shrimp) invaded the Rhine river basin. This suggests that this suspension-feeder species bears the prime responsibility for this increase, although this hypothesis requires further independent evidence. The sudden increase in the rating exponent does however not manifest itself in the long-term gradual trend of declining suspended sediment concentrations and vice versa. Apparently, the sequestration of sediment by Chelicorophium curvispinum is only temporary: the suspended sediment sequestered during periods of relatively low discharges is likely remobilised again during periods of high discharge. This implies that the invasion of Chelicorophium curvispinum has not played a significant role in the decline of suspended sediment concentrations. The precise reasons for the gradual long-term decline in suspended sediment concentration remain yet unknown.

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Marsh Processes and Their Response to Climate Change and Sea-Level Rise

Annual Review of Earth and Planetary Sciences ◽

10.1146/annurev-earth-082517-010255 ◽

2019 ◽

Vol 47 (1) ◽

pp. 481-517 ◽

Cited By ~ 18

Author(s):

Duncan M. FitzGerald ◽

Zoe Hughes

Keyword(s):

Climate Change ◽

Carbon Dioxide ◽

Sea Level Rise ◽

Suspended Sediment ◽

Sea Level ◽

Salt Marshes ◽

Biomass Productivity ◽

Sediment Supply ◽

Marsh Vegetation ◽

Suspended Sediment Concentrations

In addition to their being vital components of mid- to high-latitude coastal ecosystems, salt marshes contain 0.1% of global sequestered terrestrial carbon. Their sustainability is now threatened by accelerating sea-level rise (SLR) that has reached a rate that is many times greater than the rate at which they formed and evolved. Modeling studies have been instrumental in predicting how marsh systems will respond to greater frequencies and durations of tidal inundation and in quantifying thresholds when marshes will succumb and begin to disintegrate due to accelerating SLR. Over the short term, some researchers believe that biogeomorphic feedbacks will improve marsh survival through greater biomass productivity enhanced by warmer temperatures and higher carbon dioxide concentrations. Increased sedimentation rates are less likely due to lower-than-expected suspended sediment concentrations. The majority of marsh loss today is through wave-induced edge erosion that beneficially adds sediment to the system. Edge erosion is partly offset by upland marsh migration during SLR. ▪ Despite positive biogeomorphic feedbacks, many salt marshes will succumb to accelerating sea-level rise due to insufficient mineral sediment. ▪ The latest multivariate marsh modeling is producing predictions of marsh evolution under various sea-level rise scenarios. ▪ The least well-known variables in projecting changes to salt marshes are suspended sediment concentrations and net sediment influx to the marsh. ▪ We are in the infancy of understanding the importance and processes of marsh edge erosion and the overall dynamicism of marshes. ▪ This review defines the latest breakthroughs in understanding the response of salt marshes to accelerating sea-level rise and decreasing sediment supply. ▪ Climate change is accelerating sea-level rise, warming temperatures, and increasing carbon dioxide, all of which are impacting marsh vegetation and vertical accretion.

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Effects of River-Ice Breakup on Sediment Transport and Implications to Stream Environments: A Review

Water ◽

10.3390/w13182541 ◽

2021 ◽

Vol 13 (18) ◽

pp. 2541

Author(s):

Spyros Beltaos ◽

Brian C. Burrell

Keyword(s):

Suspended Sediment ◽

Sediment Supply ◽

River Ice ◽

Sediment Erosion ◽

Ice Jams ◽

Form And Function ◽

Ice Breakup ◽

Sharp Waves ◽

Suspended Sediment Concentrations ◽

And Function

During the breakup of river ice covers, a greater potential for erosion occurs due to rising discharge and moving ice and the highly dynamic waves that form upon ice-jam release. Consequently, suspended-sediment concentrations can increase sharply and peak before the arrival of the peak flow. Large spikes in sediment concentrations occasionally occur during the passage of sharp waves resulting from releases of upstream ice jams and the ensuing ice runs. This is important, as river form and function (both geomorphologic and ecological) depend upon sediment erosion and deposition. Yet, sediment monitoring programs often overlook the higher suspended-sediment concentrations and loads that occur during the breakup period owing to data-collection difficulties in the presence of moving ice and ice jams. In this review paper, we introduce basics of river sediment erosion and transport and of relevant phenomena that occur during the breakup of river ice. Datasets of varying volume and detail on measured and inferred suspended-sediment concentrations during the breakup period on different rivers are reviewed and compared. Possible effects of river characteristics on seasonal sediment supply are discussed, and the implications of increased sediment supply are reviewed based on seasonal comparisons. The paper also reviews the environmental significance of increased sediment supply both on water quality and ecosystem functionality.

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Detection of the Minute Variations of Total Suspended Matter in Strong Tidal Waters Based on GaoFen-4 Satellite Data

Remote Sensing ◽

10.3390/rs13071339 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1339

Author(s):

Qiong Chen ◽

Bin Zhou ◽

Zhifeng Yu ◽

Jie Wu ◽

Shilin Tang

Keyword(s):

Suspended Sediment ◽

Suspended Matter ◽

Bottom Topography ◽

Observation Time ◽

Total Suspended Matter ◽

Tidal Range ◽

Hangzhou Bay ◽

Time Interval ◽

Suspended Sediment Concentrations ◽

The Impact

Hangzhou Bay (HZB) is the largest macro-tidal bay in China, where suspended sediment concentrations are significantly modulated by tidal oscillations. This makes it an ideal area for the study of the impact of tide on temporal–spatial variation in suspended sediment. The GaoFen-4 (GF-4) satellite is the first high-resolution geosynchronous orbiting satellite of China. It exhibits the unique advantages of capturing minute variations and finer details of total suspended matter (TSM) due to the enhancement in spatial resolution (50 m) and observation time interval (20 s). In this study, TSM concentration of the HZB was retrieved based on the GF-4 satellite. The spatial distribution and minute variations of TSM concentration under the ebb tide from 7:30 to 7:40 a.m. on 28 August 2017, were analyzed. The results showed that the average TSM concentration inside HZB was (371.8 ± 1.8) mg/L. There was a linearly increasing trend of TSM concentration at ebb tide, with an increment of (3.96 ± 0.31) (mg/L)/min, and a more significant increase was observed in the high TSM areas. This increase in TSM concentration was associated with both the bottom topography and tide processes. The tidal potential energy generated by the tidal range and the strong shear stress generated by the high current velocity both led to the re-suspension of the sedimentary particles, which affected the variation of TSM concentration. In addition, the influence of bottom topography changed the intensity of re-suspension and also affected the distribution of TSM concentration in HZB.

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Monitoring of seasonal variability and movement of suspended sediment concentrations along the Thiruvananthapuram coast, southern India, using the Landsat OLI sensor

Ocean Science ◽

10.5194/os-14-1085-2018 ◽

2018 ◽

Vol 14 (5) ◽

pp. 1085-1092 ◽

Cited By ~ 2

Author(s):

Bismay Ranjan Tripathy ◽

Kaliraj Seenipandi ◽

Haroon Sajjad ◽

Pawan Kumar Joshi ◽

Bhagwan Singh Chaudhary ◽

...

Keyword(s):

Suspended Sediment ◽

Coastal Water ◽

Seasonal Variability ◽

Spectral Reflectance ◽

Suspended Sediments ◽

Southern India ◽

Landsat 8 ◽

Post Monsoon ◽

Suspended Sediment Concentrations ◽

Multi Temporal

Abstract. Studies on suspended sediment concentrations at a seasonal scale play a vital role in understanding coastal hydrodynamic processes in an area. Assessment of spatio-temporal changes in suspended sediments in nearshore areas has gained complexity due to the utilization of conventional methods; this issue can be successfully solved nowadays using multi-temporal remotely sensed images with the help of advanced image processing techniques. The present study is an attempt to demonstrate the model algorithm used to extract suspended sediment concentrations using Landsat 8 OLI (Operational Land Imager) sensor images. The study was executed in a near-offshore area of the Thiruvananthapuram coast, southern India, and focused on the extraction of suspended sediment concentrations and their seasonal variability during pre-monsoon and post-monsoon periods. The OLI images were pre-processed to obtain the actual reflectance using the FLASSH module of the ENVI v5.5 software. The generic model developed herein is designed to compute the spectral reflectance variability between coastal water and suspended sediments and to differentiate the spatial accumulation of the suspended sediment concentrations from the coastal water at the pixel scale. Maximum (0.8 % in near-infrared bands) and minimum (0.6 % in blue bands) spectral reflectance indicates the occurrence of suspended sediments in the coastal water. The model-derived results revealed that the suspended sediment concentration gradually decreased with increasing depth and distance from the shoreline. Higher sediment concentrations accumulated at lower depths in coastal water due to wave and current action that seasonally circulated the sediments. This higher concentration of the suspended sediment load was estimated to be 0.92 mg L−1 at the shallow depths (<10 m) of the coastal waters and 0.30 mg L−1 at a depth of 30 m. Seasonal variability of suspended sediments was observed in a north–south direction during the pre-monsoon; the reverse was noted during the post-monsoon period. The spatial variability of suspended sediments was indirectly proportional to the depth and distance from the shoreline, and directly proportional to offshore wave and littoral current activity. This study proves that the developed model coupled with the provided computational algorithm can be used as an effective tool for the estimation of suspended sediment concentrations using multi-temporal OLI images; furthermore, the output may be helpful for coastal zone management and conservation planning and development.

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Influence of distributary channels on sediment and organic carbon supply in event-dominated coastal margins: the Po prodelta as a study case

Biogeosciences Discussions ◽

10.5194/bgd-7-7849-2010 ◽

2010 ◽

Vol 7 (5) ◽

pp. 7849-7902

Author(s):

T. Tesi ◽

S. Miserocchi ◽

M. A. Goñi ◽

M. Turchetto ◽

L. Langone ◽

...

Keyword(s):

Water Column ◽

Suspended Sediment ◽

Surface Waters ◽

Sediment Cores ◽

Sediment Supply ◽

Channel Network ◽

The North ◽

Depositional Processes ◽

Suspended Sediment Concentrations ◽

Peak Flood

Abstract. From November 2008 through May 2009, the North Italy experienced the highest precipitation period recorded over the last century. As a result, a long series of flood events occurred in the Po river (North Italy). This series of events ended with a large flood in early May 2009. An event-response sampling was carried out in the Po prodelta in April–May 2009 to characterize this latter event and to investigate the strata preservation in the stratigraphy record as a result of this series of floods. The water sampling was carried out during two periods of the flood, including early in the event under conditions of moderate river flow (~5000 m3 s−1) and 24 h later during the peak discharge (~8000 m3 s−1). At each station, profiles of conductivity, transmittance, and fluorescence were acquired whereas surface and bottom waters were sampled to collect sediments in suspension. In addition, sediment cores were collected in the Po prodelta before and after the peak flood. Biogeochemical compositions and sedimentological characteristics of suspended and sediment samples were investigated using a multi-proxy approach that included bulk and biomarkers analyses. Furthermore, 7Be down-core profiles and radiographs were used to analyze the internal stratigraphy of sediment cores. During moderate discharge, the water column did not show evidence of plume penetration. In surface waters, suspended sediment concentrations were found to be similar to low river discharge periods whereas the main OC was autochthonous. After 24 h, during the peak flood, water column properties and biogeochemical parameters exhibited marked changes indicating significant penetration of the turbid plume. However, suspended sediment concentrations and terrigenous OC content in surface waters were still less then expected based on the discharge. These results suggested that, since material enters the Adriatic as buoyancy-driven flow with a reduced transport capacity, settling and flocculation processes result in trapping a significant fraction of land-derived material prior to reaching the subaqueous prodelta. In spite numerous floods occurred from November 2008 through April 2009, sediment cores collected in late April 2009 did not exhibited significant evidence of event-strata preservation. Since these floods were ordinary (2–3 y return period), the lack of preservation indicates that most of the sediment supply during these oridinary events does not reach the subaqueous prodelta. However, it is likely that modest sediment deposition occurs during these oridinary floods but thicknesses of these event-strata are not sufficient to compete with post-depositional processes. Stations in the north and central prodelta were re-occupied after the peak of the May 2009 flood. Based on 7Be and radiographs, we estimated that 17 and 6 cm event-layers, respectively. Selective trapping of coarse material occurred in the central prodelta likely because of the geomorphologic setting of the central outlet characterized by an estuary-like mouth. Despite these settling processes, lignin-based parameters indicated that sources of the terrigenous OC were fairly homogenous throughout the channel network and between size-fractions.

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Hindcasting and Forecasting Total Suspended Sediment Concentrations Using a NARX Neural Network

Sustainability ◽

10.3390/su13010363 ◽

2021 ◽

Vol 13 (1) ◽

pp. 363

Author(s):

Vladimir J. Alarcon

Keyword(s):

Neural Network ◽

Suspended Sediment ◽

Urban Areas ◽

Input Data ◽

Suspended Sediments ◽

Efficiency Index ◽

Open Loop ◽

Model Parameters ◽

Creek Watershed ◽

Suspended Sediment Concentrations

Estimating and forecasting suspended sediments concentrations in streams constitutes a valuable asset for sustainable land management. This research presents the development of a non-linear autoregressive exogenous neural network (NARX) for forecasting sediment concentrations at the exit of Francia Creek watershed (Valparaiso, Chile). Details are presented on input data selection, data splitting, selection of model architecture, determination of model structure, NARX training (optimization of model parameters), and model validation (hindcasting and forecasting). The study explored if the developed artificial neural network model is valid for forecasting daily suspended sediment concentrations for a complete year, capturing seasonal trends, and maximum and baseflow concentrations. Francia Creek watershed covers approximately 3.24 km2. Land cover within the catchment consists mainly of native and exotic vegetation, eroded soil, and urban areas. Input data consisting of precipitation and stream flow time-series were fed to a NARX network for forecasting daily suspended sediments (SST) concentrations for years 2013–2014, and hindcasting for years 2008–2010. Training of the network was performed with daily SST, precipitation, and flow data from years 2012 and 2013. The resulting NARX net consisted of an open-loop, 12-node hidden layer, 100 iterations, using Bayesian regularization backpropagation. Hindcasting of daily and monthly SST concentrations for years 2008 through 2010 was successful. Daily SST concentrations for years 2013 and 2014 were forecasted successfully for baseflow conditions (R2 = 0.73, NS = 0.71, and Kling-Gupta efficiency index (K-G) = 0.84). Forecasting daily SST concentrations for year 2014 was within acceptable statistical fit and error margins (R2 = 0.53, NS = 0.47, K-G = 0.60, d = 0.82). Forecasting of monthly maximum SST concentrations for the two-year period (2013 and 2014) was also successful (R2 = 0.69, NS = 0.60, K-G = 0.54, d = 0.84).

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Classifications of runoff and sediment data to improve the rating curve method

Journal of Agricultural Engineering ◽

10.4081/jae.2017.641 ◽

2017 ◽

Vol 48 ◽

Cited By ~ 4

Author(s):

Hossein Khaledian ◽

Homayoun Faghih ◽

Ata Amini

Keyword(s):

Suspended Sediment ◽

River Flow ◽

Data Classification ◽

Suspended Sediments ◽

Sediment Concentration ◽

Low Flow ◽

Rating Curve ◽

Sediment Rating Curve ◽

Curve Method ◽

Sediment Data

In this study, data classification method was evaluated to increase accuracy of estimating suspended sediment load. To achieve this objective, suspended sediment in Chehelgazi and Khalifeh-Tarkhan rivers in Kurdistan, Iran, were estimated using Sediment Rating Curve (SRC) method in three different approaches of data classification. At first, measured data were modeled without classification. Then, data based on flow statues were divided into two series as high and low flow. Eventually, based on sediment concentration, the data were divided into low and high sediment concentration. Long-term runoff and sediment data were used to calibrate rating curve model. The estimated values were compared with recorded data and the performances of these models were evaluated using statistical criteria. The results indicated an effective role of data classification to improve estimating sediment transportation by rating curve method. In one of the stations, it was observed that due to classification based on river flow and sediment concentration, model efficiency was increased about 45% and 28%, respectively. Furthermore, in case of improving efficiency of SRC method, classifying data based on flow statues was found to be more effective than sediment concentration. The results of this study can be used to improve the management of the basin by more accurately estimating the amount of suspended sediments transporting in the rivers draining to reservoirs.

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