Suspended Sediment Budget Research Articles

Delft3D model-based estuarine suspended sediment budget with morphodynamic changes of the channel-shoal complex in a mega fluvial-tidal delta

ABSTRACT Reduced riverine sediment supply and sea-level rise (SLR) threaten land building and ecosystem in deltas. However, the sediment-morphodynamic processes in a channel-shoal complex are not well understood. Here, based on bathymetry and the Delft3D model, geomorphic changes and suspended sediment budgets in the South Passage, Nanhui and Jiuduansha Shoal in the mega-Changjiang Delta were examined. Results reveal that with riverine suspended sediment concentration (SSC) decreased by 75%, the net sediment deposition rate was reduced from 4.20 cm/yr in 1979–1990 to 3.21 cm/yr in 1990–2003, and further declined to 2.21 cm/yr in 2003–2013 and 0.40 cm/yr in 2013–2020. Severe erosion occurred along the upper South Passage and extended toward the mouth bar. Strong accretions accumulated in the Nanhui and Jiuduansha Shoal. After river SSC declined from 0.53 kg/m3 to 0.35 kg/m3, 0.16 kg/m3, and 0.12 kg/m3, net suspended sediment deposition was lowered by 3.13%, 7.35% and 8.67%, respectively. Moreover, SLR of 5 cm, 15 cm, 25 cm, and 50 cm resulted in a further 1.11%, 4.18%, 4.16%, and 14.79% reduction in sediment trapping efficiency. Our findings highlight the strong likelihood that reduced river sediment input, SLRs and intensified anthropogenic effects will exacerbate sediment deficit and erosion in mega fluvial-tidal deltas.

Quantifying the contribution of bank erosion to a suspended sediment budget using boat‐mounted LiDAR and high‐frequency suspended sediment monitoring

AbstractUnderstanding the physical processes as well as the hydrological and morphological factors that influence channel bank erosion is important for river restoration and the management of the floodplain and associated ecosystems. In this study, we introduced an innovative approach to quantify river bank erosion and its contribution to a reach fine sediment budget by combining repeat bank erosion surveys using a jetboat‐mounted LiDAR scanner with concurrent high‐frequency suspended sediment load measurements into and out of the surveyed reach. Using this information, we established a sediment budget for a 5.5‐km‐long study reach of the lower Ōreti River, Southland, New Zealand. A total of three surveys were conducted along the study reach to understand changes in the bank erosion contribution to suspended sediment load at different time scales. The first two surveys were separated by a short period of 8 weeks, and the third survey followed 2.5 years later. The measured volumes of fine sediment rendered from bank erosion equated to 25% and 29% of the measured outflowing suspended load over these two inter‐survey epochs, respectively. By comparison, the net contribution of measured bank erosion and derived fine sediment deposition on the riverbed to the outflowing suspended load was 12% over the first, shorter epoch and 25% for the second, 2.5‐year epoch. These results highlight the important role of in‐channel sediment deposition in the variability of net suspended sediment exports from channel reaches experiencing bank erosion. The approach used in this study has a unique capability to accurately monitor bank erosion and obtain high‐resolution topography data capturing changes in river banks over different time periods.

Assessment of Suspended Sediment Budget of the Lena River Delta Based on the Remote Sensing Dataset

Assessment of Suspended Sediment Budget of the Lena River Delta Based on the Remote Sensing Dataset

North to South Variations in the Suspended Sediment Transport Budget within Large Siberian River Deltas Revealed by Remote Sensing Data

This study presents detailed suspended sediment budget for the four Siberian river deltas, representing contrasting conditions between Northern and Southern environments. Two of the studied rivers empty their water and sediments into the marine located in the permafrost zone in the Arctic region (Lena and Kolyma), and the other two (Selenga and Upper Angara) flow into Lake Baikal located in the steppe and forest-steppe zone of Southern Siberia. For the first time, these poorly monitored areas are analyzed in terms of the long-term and seasonal changes of spatial patterns of suspended sediment concentrations (SSC) over distributaries systems. Remote sensing reflectance is derived from continuous time series of Landsat images and calibrated with the onsite field measurements of SSC. Seasonal variability of suspended sediment changes over deltas was captured for the period from 1989 to 2020. We identify significant variability in the sedimentation processes between different deltas, which is explained by particularities of deltas networks and geomorphology and the existence of specific drivers—continuous permafrost impact in the North and abundant aquatic vegetation and wetland-dominated areas in the South. The study emphasizes that differences exist between Northern and Southern deltas regarding suspended sediments transport conditions. Mostly retention of suspended sediment is observed for Southern deltas due to sediment storage at submerged banks and marshlands located in the backwater zone of the delta during high discharges. In the Northern (arctic) deltas due to permafrost impacts (melting of the permafrost), the absence of sub-aquatic banks and river to ocean interactions of suspended sediment transport is mostly increased downwards, predominantly under higher discharges and along main distributary channels. These results shine light on the geochemical functions of the deltas and patterns of sequestering various metals bound to river sediments.

Suspended sediment budget and intra-event sediment dynamics of a small glaciated mountainous catchment in the Northern Caucasus

The sediment dynamics of (peri-)glacial catchments can be highly variable and complex. Understanding these dynamics and their underlying causes is not only of interest from a scientific perspective but also required to address the practical problems with which they are often associated. In order to better understand the sediment dynamics of glaciated mountainous catchments, suspended sediment fluxes in the 9.1 km2 Djankuat catchment (North Caucasus, Russia) were monitored intensively during the 2017 ablation season. The intra-event suspended sediment dynamics were studied using a newly proposed simple hysteresis index (SHI), quantifying to what extent evolutions in sediment concentration are characterized by a clockwise or anticlockwise hysteresis loop. The resulting catchment suspended sediment yield was 1033 t km−2 year−1, with the glacier itself contributing 72% of the suspended sediment load. However, during rainfall events, also hillslope erosion in the proglacial area became a very significant sediment source. Clockwise hysteresis loops occurred in 61.8% of the events, while anticlockwise in 11.8%. On the other hand, only 47.8% of the total suspended sediment flux was transported during clockwise events. Our observations clearly indicate that events showing a stronger clockwise pattern (i.e., a higher SHI) are associated with a larger sediment input from the proglacial area. Overall, our results provide data and insights on sediment dynamics in an understudied environment. They illustrate that the type and characteristics of sediment concentration hysteresis loops are to some extent linked to the dominant sediment sources during the event. As such, the proposed methodology and SHI may also help with a better understanding of sediment dynamics in other environments.

Evolution of Suspended Sediment Budget in the Deltas of Lake Baikal Tributaries

The monitoring, field, and satellite datasets are used to estimate changes in suspended sediment budget for the Selenga and Upper Angara river deltas. Sediment deficit during recent decades dominates delta evolution due to decrease in the sediment delivery to the delta since the middle of the 1970s by 51% for the Selenga River and by 70% for the Upper Angara River. The observed decline in the sediment runoff and peak water flows associated with the sediment deposition within the inundated flood-plain of the deltas leads to the reduction of the sediment aggradation rates over both deltas. Under low water flows we observed longitudinal increase of the sediment transport rates along Selenga River delta; the Upper Angara constantly reduces sediment transport rates under various hydrological conditions.

Water and Suspended Sediment Budgets in the Lower Mekong from High-Frequency Measurements (2009–2016)

Based on a new dataset of high temporal resolution of water discharge (hourly frequency) and suspended sediment concentration (twice daily frequency at ebb and flood tides) at Can Tho and My Thuan stations during the 2009–2016 period, monthly and annual flow and suspended sediment flux of the lower Mekong River were calculated. The present water discharge of the Mekong River to the sea can be estimated to be 400 km3 yr−1, +/− 100 km3 yr−1 depending on El Niño Southern Oscillation (ENSO), and the present sediment supply to the sea can be estimated to be 40 Mt yr−1, +/− 20 Mt yr−1 depending on ENSO. The ENSO influence (proxied by the Southern Oscillation Index—SOI) on Q (water discharge) and Qs (sediment flux) is at maximum at a time lag of 8–9 months. The 2010–2011 La Niña event increased the water supply by almost 30% and the sediment supply by 55% in 2011. The 2015–2016 El Niño event decreased the water supply by 20% and the sediment supply by 50% in 2015–2016. The average net water discharge was 12,550 m3 s−1 in neutral years. The Tien River at My Thuan accounted for ~52%, and the Hau River at Can Tho for ~48% of the total Mekong River discharge, with small variations (of the order 1%) amongst years. In terms of suspended sediment delivery to the sea, the Tien River accounted for a more variable portion of 55% in neutral years, 57.3% in 2015–2016 (El Niño) and 62% in 2011 (La Niña). 80% of water discharge occurred during the flood season (July–December) and 20% occurred in the low flow season (January–June), the proportion being 91% and 9% for the sediment supply. Previous estimates of annual sediment supplies to the sea (145–160 Mt yr−1) had been established before 2003. Possible origins of the recent reduction by ~75% of sediment supply are presented and discussed.

Contemporary fluvial geomorphology and suspended sediment budget of the partly confined, mixed bedrock-alluvial South River, Virginia, USA

Contemporary fluvial geomorphology and suspended sediment budget of the partly confined, mixed bedrock-alluvial South River, Virginia, USA

Impact of the spatial resolution of satellite remote sensing sensors in the quantification of total suspended sediment concentration: A case study in turbid waters of Northern Western Australia.

The impact of anthropogenic activities on coastal waters is a cause of concern because such activities add to the total suspended sediment (TSS) budget of the coastal waters, which have negative impacts on the coastal ecosystem. Satellite remote sensing provides a powerful tool in monitoring TSS concentration at high spatiotemporal resolution, but coastal managers should be mindful that the satellite-derived TSS concentrations are dependent on the satellite sensor’s radiometric properties, atmospheric correction approaches, the spatial resolution and the limitations of specific TSS algorithms. In this study, we investigated the impact of different spatial resolutions of satellite sensor on the quantification of TSS concentration in coastal waters of northern Western Australia. We quantified the TSS product derived from MODerate resolution Imaging Spectroradiometer (MODIS)-Aqua, Landsat-8 Operational Land Image (OLI), and WorldView-2 (WV2) at native spatial resolutions of 250 m, 30 m and 2 m respectively and coarser spatial resolution (resampled up to 5 km) to quantify the impact of spatial resolution on the derived TSS product in different turbidity conditions. The results from the study show that in the waters of high turbidity and high spatial variability, the high spatial resolution WV2 sensor reported TSS concentration as high as 160 mg L-1 while the low spatial resolution MODIS-Aqua reported a maximum TSS concentration of 23.6 mg L-1. Degrading the spatial resolution of each satellite sensor for highly spatially variable turbid waters led to variability in the TSS concentrations of 114.46%, 304.68% and 38.2% for WV2, Landsat-8 OLI and MODIS-Aqua respectively. The implications of this work are particularly relevant in the situation of compliance monitoring where operations may be required to restrict TSS concentrations to a pre-defined limit.

Evaluation of stream water quality data generated from MODIS images in modeling total suspended solid emission to a freshwater lake

Modeling of suspended sediment emission into freshwater lakes is challenging due to data gaps in developing countries. Existing models simulate sediment concentration at a gauging station upstream and none of these studies had modeled total suspended solids (TSS) emissions by inflowing rivers to freshwater lakes as there are no TSS measurements at the river mouth in the upper Blue Nile basin. In this study a 10year TSS time series data generated from remotely sensed MODIS/Terra images using established empirical relationship is applied to calibrate and validate a hydrology model for Lake Tana in Upper Blue Nile Basin. The result showed that at a monthly time scale TSS at the river mouth can be replicated with Nash–Sutcliffe efficiency (NS) of 0.34 for calibration and 0.21 for validation periods. Percent bias (PBIAS) and ratio of the root-mean-square error to the standard deviation of measured data (RSR) are all within range. Given the inaccessibility and costliness to measure TSS at river mouths to a lake the results found here are considered useful for suspended sediment budget studies in water bodies of the basin.

Effects of placer mining on suspended sediment budget: case study of north of Russia’s Kamchatka Peninsula

Placer mines are located in river valleys, along river benches, or along the pathways of ancient channels. Open-pit mining alters the stream hydrology and enhances sediment transport. The present study focuses on sediment transport in the area of the platinum placer mining located at the north of Russia’s Kamchatka Peninsula (Seynav-Galmoenan placer deposits). Based on hydrological field investigations, a conceptual model was derived to assess anthropogenic effects on the total sediment budget of rivers. The model illustrates key processes controlling sediment dynamics in the Vyvenka River basin. Field work included water-discharge and sediment-load measurements, assessment of annual channel change in rivers in mining site areas, and evaluation of the relative importance of sediment sources and transport processes. In this study, we estimated total sediment delivery from opencast placer mining of 60 t year-1; the annual mass wasting rate ranges from 2 to 5.5 kg m-2 year-1, which is three orders of magnitude higher than from non-mined streams. Mass wasting dominates surface erosion on the hillslopes and produces significant wastewater effluents; however, erosion of the artificially stratified channel reaches is the primary contributor to the annual sediment yield of the mined rivers (21.4%).Editor D. KoutsoyiannisCitation Chalov, S.R., 2014. Effects of placer mining on suspended sediment budget: case study of north of Russia’s Kamchatka Peninsula. Hydrological Sciences Journal, 59 (5), 1081–1094.

Storage, properties and seasonal variations in fine‐grained bed sediment within the main channel and headwaters of the River Sanginjoki, Finland

AbstractLowland catchments in Finland are intensively managed, promoting erosion and sedimentation that negatively affects aquatic environments. This study quantified fine‐grained bed sediment in the main channel and upstream headwaters of the River Sanginjoki (399.93 km2) catchment, Northern Finland, using remobilization sediment sampling during the ice‐free period (May 2010–December 2011). Average bed sediment storage in river was 1332 g m−2. Storage and seasonal variations were greater in small headwater areas (total bed sediment storage mean 1527 g m−2, range 122–6700 g m−2 at individual sites; storage of organic sediment: mean 414 g m−2, range 27–3159 g m−2) than in the main channel (total bed sediment storage: mean 1137 g m−2, range 61–4945 g m−2); storage of organic sediment: mean 329 g m−2, range 13–1938 g m−2). Average reach‐specific bed sediment storage increased from downstream to upstream tributaries. In main channel reaches, mean specific storage was 8.73 t km−1, and mean specific storage of organic sediment 2.45 t km−1, whereas in tributaries, it was 126.94 and 34.05 t km−1, respectively. Total fine‐grained bed sediment storage averaged 563 t in the main channel and 6831 t in the catchment. The proportion of mean organic matter at individual sites was 15–47% and organic carbon 4–455 g C m−2, with both being highest in small headwater tributaries. Main channel bed sediment storage comprised 52% of mean annual suspended sediment flux and stored organic carbon comprised 7% of mean annual total organic carbon load. This indicates the importance of small headwater brooks for temporary within‐catchment storage of bed sediment and organic carbon and the significance of fine‐grained sediment stored in channels for the suspended sediment budget of boreal lowland rivers. Copyright © 2013 John Wiley & Sons, Ltd.

The sediment budget of a large river regulated by dams (The lower River Ebro, NE Spain)

Purpose The aim of this work was to develop a comprehensive fluvial suspended sediment budget for a large regulated river, the lower River Ebro (NE Spain).

A suspended sediment budget for the agricultural Can Revull catchment (Mallorca, Spain)

Extensive rainfed herbaceous crops are one of the most representative agricultural elements of Mediterranean region, which should be one of the major factors affecting erosion processes. Although land use is commonly seen as resulting in increased sediment yields, the implementation of soil and water conservation practices can have the reverse effect. A sediment budget has been established in Can Revull, a small agricultural catchment (1.03 km2) on the island of Mallorca, by using 137Cs measurements, sediment source fi ngerprinting and more traditional monitoring techniques to quantify the individual components of the budget. A large proportion of the material mobilized from cultivated fi elds without conservation practices (gross erosion of 775 t yr 1, 1,270 t km 2 yr 1) was subsequently deposited either within the fi eld of origin (112 t yr 1, 180 t km 2 yr 1) or at intermediate locations between the source fi eld and the channel network (fi eld-to-channel conveyance loss was 454 t yr 1, 744 t km 2 yr 1). The estimates of sediment accumulation rates on the fl oodplain in the lower reaches of the catchment indicate that the mean sedimentation rate was 0.14 g cm-2 yr-1. This value was extrapolated to the total area of the fl oodplain to estimate a total annual conveyance loss or storage of 445 t yr 1. Monitoring at the catchment outlet over the study period (2004–2008) indicated a mean annual suspended sediment yield of 7 t km-2 yr-1. The sum of the estimates of sediment yield and fl oodplain storage (452 t yr-1) was taken to represent the total annual input of suspended sediment to the channel system. This value was subsequently apportioned using the information provided by the fi ngerprinting investigation, to estimate the mass of sediment reaching the channel network from cultivated fi elds and from eroding channel banks. Thus the annual contribution from channel banks was estimated to be 242 t yr-1. In the case of the contributions from cultivated fi elds, the estimates obtained were, as expected, signifi cantly less than the values of net soil loss from these zones provided by the 137Cs measurements due to conveyance losses associated to fi eld-to-channel conveyance loss. The overall sediment delivery ratios (< 1 %) indicate that approximately 99 % of the sediment mobilized by erosion within the Can Revull catchment is subsequently deposited before reaching the monitoring station. As such, the low sediment outputs from the study catchment should be seen as refl ecting the importance of conveyance losses and storage rather than a lack of sediment mobilization from the catchment surface, although part of the catchment headwaters was modifi ed historically by means of terraces and transverse walls to prevent erosion.

Fluxo de sedimentos em suspensão nos rios da Amazônia

The Amazon River Basin extends over 6 million km² and releases a fresh water volume of 6.000 109 m³.ano-¹ to the Atlantic Ocean. About 50% of the area of the basin corresponds to the pre-Cambrian lands, the shields, 12% correspond to the Andean chain and the remain corresponds to the Amazonian plain. As a result of the Andean chain erosion, the transport of sediments at the Amazon basin until the Ocean, has in the rivers its main agent. The studies concerning this transport, have been rarefaied and most of them concentrated a long of the great central valley and sometimes,very rare, in some of its main tributaries. This study presents a vision of that subject since the level of the measurement sections at hydrometric stations until the continental scale. We evaluate the distribution of the total suspended sediment budget at the Amazonian Basin and some methods to calculate suspended sediment discharge as well. We also quantifying the contributions of the main sources of sediments, including the shields, until know inedit. Finally, we analyze distinct databases and evaluate the total contributions of the River Amazon in terms of annual flow of suspended sediments to the Atlantic Ocean, considering a new value, which resulted in a variation between 600 to 800 million tons.

A review of the suspended sediment budget at the confluence of the Paraná and Paraguay Rivers

AbstractIn this paper, the sediment budget at the confluence of the Paraná–Paraguay Rivers is updated on the basis of new suspended sediment concentration data, obtained during the 1990s at carefully located cross‐sections, after the construction of several large reservoirs. With these data, it was possible to estimate that the suspended sediment load transported by the Upper Paraná River had decreased by 60% due to the influence of the dams. This decrease occurred in spite of the influence of climate change across the Upper Paraná and Paraguay basin, which increased the precipitation and surface runoff. As a consequence of these anthropogenic and natural processes, the Bermejo River (the main source of wash load to the system) accounts for an increasing proportion of the sediment transport along the middle and lower reaches of the Paraná River. The Paraná River currently transports about 120 × 106 t year−1 of wash load, with nearly 90% of this being supplied by the Bermejo. The contribution from the Bermejo is now about 35% larger than its contribution during the 1970s, when it accounted for approximately 60% of the sediment load of the Paraná River. These changes that have occurred over the last 30 years have enhanced the natural asymmetrical distribution of solid and water discharges in the Paraná River basin. Copyright © 2009 John Wiley &amp; Sons, Ltd.

A suspended sediment budget of the yichang‐wuhan reach of the yangtze river, china

.The amount of the sediment deposition in the Yichan‐Wuhan reach of the middle Yangtze River (also known as Changjiang River) has been determined using the concept of sediment budget at the channel‐reach scale. The fill‐scour processes of the middle Yangtze River were studied during the period 1956–1997 in response to the variation in sediment load and flow inputs. The results show that 13.3% of the net input of sediment was deposited in the studied river reach. Since 1956, the output sediment load of the studied reach increased with time to 1981, followed by a decline. The increase in output before 1981 can be related to the man‐made bend neck‐cutoff which caused a decrease in the sediment load diverted through the ‘three outfalls’ (i.e. the three distributaries from the Yangtze main stem to the Dongting Lake) and increased the sediment‐carrying capacity of the river. Thereby, the river could transport more sediment to the outlet of the studied river reach. The decrease in the sediment load output after 1984 was directly due to the decreased sediment load at Yichang station. Multiple regression equations have been established to assess the contributions of influencing factors to the variation in sediment deposition amount in the studied river reach.

SEDIMENT YIELD AND SUSPENDED SEDIMENT TRANSPORT IN THE CHIKUGOGAWA RIVER BASIN

Turbidity was measured continuously and suspended sediment samples were collected at the 17 gage stations in the Chikugogawa River basin, the suspended sediment budget and the characteristics of sediment rating curve were studied. The relationship between turbidity and suspended sediment concentration were analyzed for each stream, the nephelometric backscatter became much weaker with steep and small stream. The suspended sediment load was integrated for flood period of 2006, the sediment budget in the whole basin, the reservoir sedimentation by fine solids and the additional sediment supply to the flood water by river bed erosion in the estuarine channel were explained. The sediment rating curve for each stream were developed, it is shown that the coefficients of power function were affected by the watershed conditions such as topography, land use, rainfall and area.

Suspended sediment and discharge relationships to identify bank degradation as a main sediment source on small agricultural catchments

AbstractVariability of suspended sediment concentration (SSC) versus discharge relationships in streams is often high and illustrates variable particle origins or availability. Particle availability depends on both new sediment supply and deposited sediment stock. The aim of this study is to improve SSC–discharge relationship interpretation, in order to determine the origins of particles and to understand the temporal dynamics of particles for two small streams in agricultural catchments from northwestern France. SSC and discharge were continuously recorded at the outlets and data were examined at different time‐scales: yearly, monthly, with distinction between flood periods and non‐flooding periods, and individual flood events. Floods are classified in relation to SSC–discharge hysteresis, and this typology is completed by the analysis of SSC–discharge ranges during rising and falling flow. We show that particles are mainly coming from channel, banks, either by hydraulic erosion or by cattle trampling. Particle availability presents a seasonal dynamics with a maximum at the beginning of autumn when discharge is low, decreasing progressively during autumn to become a minimum in winter when discharge is the highest, and increasing again in spring. Bank degradation by cattle is the determining factor in the suspended sediment dynamics. Cattle bank‐trampling produces sediment, mostly from spring to autumn, that supplies the deposited sediment stock even outside floods. This hydrologically independent process hides SSC–discharge correlation classically linked to hydraulic erosion and transport. Differences in SSC–discharge relationships and suspended sediment budgets between streams are related to differences in transport capacity and bank degradation by cattle trampling and channelization. Copyright © 2007 John Wiley &amp; Sons, Ltd.

Suspended Sediment Budget of Paddy Fields in Rainfall-runoff Events on the Ishigaki Island

Suspended Sediment Budget of Paddy Fields in Rainfall-runoff Events on the Ishigaki Island