Temporal variability of suspended sediment sources in an alpine catchment combining river/rainfall monitoring and sediment fingerprinting

Influence of the rainfall regime on erosion and transfer of suspended sediment in a 905‐km² mountainous catchment of the southern French Alps was investigated by combining sediment monitoring, rainfall data, and sediment fingerprinting (based on geochemistry and radionuclide concentrations). Suspended sediment yields were monitored between October 2007 and December 2009 in four subcatchments (22–713 km²). Automatic sediment sampling was triggered during floods to trace the sediment origin in the catchment. Sediment exports at the river catchment outlet (330 ± 100 t km^‐2 yr^‐1) were mainly driven (80%) by widespread rainfall events (long duration, low intensities). In contrast, heavy, local and short duration storms, generated high peak discharges and suspended sediment concentrations in small upstream torrents. However, these upstream floods had generally not the capacity to transfer the sediment down to the catchment outlet and the bulk of this fine sediment deposited along downstream sections of the river. This study also confirmed the important contribution of black marls (up to 70%) to sediment transported in rivers, although this substrate only occupies c. 10% of the total catchment surface. Sediment exports generated by local convective storms varied significantly at both intra‐ and inter‐flood scales, because of spatial heterogeneity of rainfall. However, black marls/marly limestones contribution remained systematically high. In contrast, widespread flood events that generate the bulk of annual sediment supply at the outlet were characterized by a more stable lithologic composition and by a larger contribution of limestones/marls, Quaternary deposits and conglomerates, which corroborates the results of a previous sediment fingerprinting study conducted on riverbed sediment. Copyright © 2012 John Wiley & Sons, Ltd.     

Assessment of suspended sediment transport in four alpine watersheds (France): influence of the climatic regime

High‐frequency water discharge and suspended sediment concentration (SSC) databases were collected for 3 years on four contrasted watersheds: the Asse and the Bléone (two Mediterranean rainfall regime watersheds) and the Romanche and the Ferrand (two rainfall–snowmelt regime watersheds). SSCs were calculated from turbidity recordings (1‐h time step), converted into SSC values. The rating curve was calculated by means of simultaneous SSC measurement taken by water sampling and turbidity recording. Violent storms during springtime and autumn were responsible for suspended sediment transport on the Asse and the Bléone rivers. On the Ferrand and the Romanche, a large share of suspended sediment transport was also caused by local storms, but 30% of annual fluxes results from snowmelt or icemelt which occurred from April to October. On each watershed, SSC up to 50 g l^?1 were observed. Annual specific fluxes ranged from 450 to 800 t km^?2 year^?1 and 40–80% of annual suspended sediment fluxes occurred within 2% of the time. These general indicators clearly demonstrate the intensity of suspended sediment transport on these types of watersheds. Suspended sediment fluxes proved to be highly variable at the annual scale (inter‐annual variability of specific fluxes) as well as at the event scale (through a hysteresis loop in the SSC/Q relationship) on these watersheds. In both cases, water discharge and precipitations were the main processes involved in suspended sediment production and transport. The temporal and spatial variability of hydro‐meteorological processes on the watershed provides a better understanding of suspended sediment dynamics. Copyright © 2009 John Wiley & Sons, Ltd.     

Interannual variation of suspended sediment load and sediment yield in an alpine catchment

Abstract

The results are described of 16 years operation of a measuring station for the automatic recording of water discharge, bed load and suspended sediment transport in the Rio Cordon catchment, a small alpine basin (5 km²) located in northeastern Italy. Hillslope erosion processes were investigated by surveying individual sediment sources repeatedly. Annual and seasonal variations of suspended sediment load during the period 1986–2001 are analysed along with their contribution to the total sediment yield. The results show that suspended load accounted for 76% of total load and that most of the suspended sediment transport occurred during two flood events: an extreme summer flash flood in September 1994 (27% of the 16-years total suspended load) and a snowmelt-induced event in May 2001 accompanied by a mud flow which fed the stream with sediments. The role of active sediment source areas is discussed in relation to the changes in flood peak—suspended load trends which became apparent after both the 1994 and the 2001 events.     

Fluvial transport of suspended sediment and organic carbon during flood events in a large agricultural catchment in southwest France

Water draining from a large agricultural catchment of 1 110 km² in southwest France was sampled over an 18‐month period to determine the temporal variability in suspended sediment (SS) and dissolved (DOC) and particulate organic carbon (POC) transport during flood events, with quantification of fluxes and controlling factors, and to analyze the relationships between discharge and SS, DOC and POC. A total of 15 flood events were analyzed, providing extensive data on SS, POC and DOC during floods. There was high variability in SS, POC and DOC transport during different seasonal floods, with SS varying by event from 513 to 41 750 t; POC from 12 to 748 t and DOC from 9 to 218 t. Overall, 76 and 62% of total fluxes of POC and DOC occurred within 22% of the study period. POC and DOC export from the Save catchment amounted to 3090 t and 1240 t, equivalent to 1·8 t km^?2 y^?1 and 0·7 t km^?2 y^?1, respectively. Statistical analyses showed that total precipitation, flood discharge and total water yield were the major factors controlling SS, POC and DOC transport from the catchment. The relationships between SS, POC and DOC and discharge over temporal flood events resulted in different hysteresis patterns, which were used to deduce dissolved and particulate origins. In both clockwise and anticlockwise hysteresis, POC mainly followed the same patterns as discharge and SS. The DOC‐discharge relationship was mainly characterized by alternating clockwise and anticlockwise hysteresis due to dilution effects of water originating from different sources in the whole catchment. Copyright © 2011 John Wiley & Sons, Ltd.     

Present-day sediment dynamics of the Sanaga catchment (Cameroon): from the total suspended sediment (TSS) to erosion balance

ABSTRACT

Total suspended sediment (TSS) data for 1960–1970 and from recent investigations (1990–2000) are used to evaluate the variability in sediment yield of the Sanaga catchment (Cameroon) and the equivalent rates of erosion. At the annual and seasonal time scales, total suspended sediment concentrations for the Mbam sub-catchment are three to four times higher than for the Sanaga basin, reflecting the higher sensitivity of the former to erosion. Classical clockwise hysteresis loops are observed in both sub-catchments, despite a significant increase in human-induced catchment changes. At the multi-year time frame (over a 40-year period), it appears that the second half of the 1990s is marked by a downward trend in TSS. This shift is due to the control infrastructures (river impoundments and ponds) installed in certain parts of the whole catchment, combined with a drop in annual rainfall and river discharge.

Editor Z.W. Kundzewicz; Associate editor not assigned     

Reintroduced large wood modifies fine sediment transport and storage in a lowland river channel

This paper explores changes in suspended sediment transport and fine sediment storage at the reach and patch scale associated with the reintroduction of partial large wood (LW) jams in an artificially over‐widened lowland river. The field site incorporates two adjacent reaches: a downstream section where LW jams were reintroduced in 2010 and a reach immediately upstream where no LW was introduced. LW pieces were organized into ‘partial’ jams incorporating several ‘key pieces’ which were later colonized by substantial stands of aquatic and wetland plants. Reach‐scale suspended sediment transport was investigated using arrays of time‐integrated suspended sediment samplers. Patch‐scale suspended sediment transport was explored experimentally using turbidity sensors to track the magnitude and velocity of artificially generated sediment plumes. Fine sediment storage was quantified at both reach and patch scales by repeat surveys of fine sediment depth. The results show that partial LW jams influence fine sediment dynamics at both the patch and reach scale. At the patch‐scale, introduction of LW led to a reduction in the concentration and increase in the time lag of released sediment plumes within the LW, indicating increased diffusion of plumes. This contrasted with higher concentrations and lower time lags in areas adjacent to the LW; indicating more effective advection processes. This led to increased fine sediment storage within the LW compared with areas adjacent to the LW. At the reach‐scale there was a greater increase in fine sediment storage through time within the restored reach relative to the unrestored reach, although the changes in sediment transport responsible for this were not evident from time‐integrated suspended sediment data. The results of the study have been used to develop a conceptual model which may inform restoration design. Copyright © 2017 John Wiley & Sons, Ltd.     

Sediment transport in an alpine river before and after a dambreak flood event

Fluvial sediment transport in the high mountain Partnach River (Reintal Valley, Bavarian Alps) was investigated during a 10‐year observation period (2001–2010). During this period, the downstream reach of the Partnach River was decoupled from upstream sediment throughput by a rockslide deposit until 2005. In August 2005, the dam was partially breached during a flood event resulting in renewed sediment coupling between the upstream and downstream reaches. A comparison of pre‐ and post‐dambreak river sediment load data showed that the dissolved load dominated sediment transport prior to August 2005 with a switch to the dominance of bedload transport, post‐dambreak. The higher post‐dambreak bedload rates were particularly evident during the first years after the dam failure due to significant coarse material coupling between active sediment sources (undercut banks/talus cones) and the Partnach River. In the last years of the observation period (2009 and 2010) the dominance of dissolved load transport was re‐established. Copyright © 2011 John Wiley & Sons, Ltd.     

Combining suspended sediment monitoring and fingerprinting to determine the spatial origin of fine sediment in a mountainous river catchment

An excess of fine sediment (grain size <2 mm) supply to rivers leads to reservoir siltation, water contamination and operational problems for hydroelectric power plants in many catchments of the world, such as in the French Alps. These problems are exacerbated in mountainous environments characterized by large sediment exports during very short periods. This study combined river flow records, sediment geochemistry and associated radionuclide concentrations as input properties to a Monte Carlo mixing model to quantify the contribution of different geologic sources to river sediment. Overall, between 2007 and 2009, erosion rates reached 249 ± 75 t km^?2 yr^?1 at the outlet of the Bléone catchment, but this mean value masked important spatial variations of erosion intensity within the catchment (85–5000 t km^?2 yr^?1). Quantifying the contribution of different potential sources to river sediment required the application of sediment fingerprinting using a Monte Carlo mixing model. This model allowed the specific contributions of different geological sub‐types (i.e. black marls, marly limestones, conglomerates and Quaternary deposits) to be determined. Even though they generate locally very high erosion rates, black marls supplied only a minor fraction (5–20%) of the fine sediment collected on the riverbed in the vicinity of the 907 km² catchment outlet. The bulk of sediment was provided by Quaternary deposits (21–66%), conglomerates (3–44%) and limestones (9–27%). Even though bioengineering works conducted currently to stabilize gullies in black marl terrains are undoubtedly useful to limit sediment supply to the Bléone river, erosion generated by other substrate sources dominated between 2007 and 2009 in this catchment. Copyright © 2011 John Wiley & Sons, Ltd.     

Predictability of river flow and suspended sediment transport in the Mississippi River basin: a non‐linear deterministic approach

As the Mississippi River plays a major role in fulfilling various water demands in North America, accurate prediction of river flow and sediment transport in the basin is crucial for undertaking both short‐term emergency measures and long‐term management efforts. To this effect, the present study investigates the predictability of river flow and suspended sediment transport in the basin. As most of the existing approaches that link water discharge, suspended sediment concentration and suspended sediment load possess certain limitations (absence of consensus on linkages), this study employs an approach that presents predictions of a variable based on history of the variable alone. The approach, based on non‐linear determinism, involves: (1) reconstruction of single‐dimensional series in multi‐dimensional phase‐space for representing the underlying dynamics; and (2) use of the local approximation technique for prediction. For implementation, river flow and suspended sediment transport variables observed at the St. Louis (Missouri) station are studied. Specifically, daily water discharge, suspended sediment concentration and suspended sediment load data are analysed for their predictability and range, by making predictions from one day to ten days ahead. The results lead to the following conclusions: (1) extremely good one‐day ahead predictions are possible for all the series; (2) prediction accuracy decreases with increasing lead time for all the series, but the decrease is much more significant for suspended sediment concentration and suspended sediment load; and (3) the number of mechanisms dominantly governing the dynamics is three for each of the series. Copyright © 2005 John Wiley & Sons, Ltd.     

Stereophotogrammetry of archive data and topographic approaches to debris‐flow torrent measurements: calculation of channel‐sediment states and a partial sediment budget for Manival torrent (Isère,France)

This paper focuses on a topographic methodology to characterize the amount of sediment stored in channels and the use of historical photographs for aerial survey by stereophotogrammetry, as part of wider research on debris‐flow magnitude prediction. The topographic methodology uses equidistant four‐point cross‐sections along the long profile of the channel. Each cross‐section is representative of a 50‐m reach of the channel. To calculate the volume of each reach, the difference is calculated between a reference level and the topographic surface. The reference level is the lowest level where the debris flow can erode, and in the current method this level is estimated from fixed points along the long profile of the channel. The accuracy of the method has been estimated by comparing results of a detailed topographic survey, with a standard deviation corresponding to about 6 per cent of the total calculated sediment volume. This topographic methodology has been used on aerial photographs by photogrammetry. This tool was applied to photographs taken on 12 past dates. The scales of the archive photographs used range from 1:3000 to 1:30 000, but results are consistent and permit us to calculate sediment states of the channel for different past dates with an uncertainty of about 6 per cent of the total volume. The application of the technique to the Manival debris‐flow torrent has permitted us to propose some partial sediment budgets and erosion‐rate estimates. Copyright © 2006 John Wiley & Sons, Ltd.     

Temporal variation of suspended sediment transport in the Koga catchment,North Western Ethiopia and environmental implications

Event sediment transport and yield were studied for 45 events in the upstream part of the 260 km² agricultural Koga catchment that drains to an irrigation reservoir. Discharge and turbidity data were collected over a period of more than a year, accompanied by grab sampling. Turbidity was very well correlated with the sediment concentrations from the samples (r = 0.99), which allowed us to estimate the temporal patterns of sediment concentrations within events. The hysteresis patterns between discharge and sediment concentrations were analysed to provide insight into the different sediment sources. Anticlockwise patterns are the dominant hysteresis patterns in the area, suggesting smaller contributions of suspended sediment from the river channels than from the hillslopes and agricultural areas. Complicated types of hysteresis patterns were mostly observed for long events with multiple peaks. For a given discharge, sediment yields in August and September, when the catchment was almost completely covered with vegetation, were much smaller than during the rest of the rainy season. The hysteresis patterns and timing suggest that the sediment availability from the agricultural areas and hillslopes affects sediment yields more strongly than does peak discharge. Two distinct types of sediment rating curves were observed for the season when the agricultural land was covered with vegetation and when it was not, indicating the dominating contribution of land use/cover to sediment yields in the catchment. The rate of suspended sediment transport in the area was estimated as 25.6 t year^?1 ha^?1. Copyright © 2013 John Wiley & Sons, Ltd.     

A discontinuous finite element suspended sediment transport model for water quality assessments in river networks

Suspended sediment plays an important role in the distribution and transport of many pollutants (such as radionuclides) in rivers. Pollutants may adsorb on fine suspended particles (e.g. clay) and spread according to the suspended sediment movement. Hence, the simulation of the suspended sediment mechanism is indispensable for realistic transport modelling. This paper presents and tests a simple mathematical model for predicting the suspended sediment transport in river networks. The model is based on the van Rijn suspended load formula and the advection–diffusion equation with a source or sink term that represents the erosion or deposition fluxes. The transport equation is solved numerically with the discontinuous finite element method. The model evaluation was performed in two steps, first by comparing model simulations with the measured suspended sediment concentrations in the Grote Nete–Molse Nete River in Belgium, and second by a model intercomparison with the sediment transport model NST MIKE 11. The simulations reflect the measurements with a Nash‐Sutcliffe model efficiency of 0.6, while the efficiency between the proposed model and the NST MIKE 11 simulations is 0.96. Both evaluations indicate that the proposed sediment transport model, that is sufficiently simple to be practical, is providing realistic results.     

Assessment of intermediate fine sediment storage in a braided river reach (southern French Prealps)

This paper presents a field investigation on river channel storage of fine sediments in an unglaciated braided river, the Bès River, located in a mountainous region in the southern French Prealps. Braided rivers transport a very large quantity of bedload and suspended sediment load because they are generally located in the vicinity of highly erosive hillslopes. Consequently, these rivers play an important role because they supply and control the sediment load of the entire downstream fluvial network. Field measurements and aerial photograph analyses were considered together to evaluate the variability of fine sediment quantity stored in a 2·5‐km‐long river reach. This study found very large quantities of fine sediment stored in this reach: 1100 t per unit depth (1 dm). Given that this reach accounts for 17% of the braided channel surface area of the river basin, the quantities of fine sediment stored in the river network were found to be approximately 80% of the mean annual suspended sediment yields (SSYs) (66 200 t year^?1), comparable to the SSYs at the flood event scale: from 1000 t to 12 000 t depending on the flood event magnitude. These results could explain the clockwise hysteretic relationships between suspended sediment concentrations and discharges for 80% of floods. This pattern is associated with the rapid availability of the fine sediments stored in the river channel. This study shows the need to focus on not only the mechanisms of fine sediment production from hillslope erosion but also the spatiotemporal dynamics of fine sediment transfer in braided rivers. Copyright © 2010 John Wiley & Sons, Ltd.     

Flow behaviour,suspended sediment transport and transmission losses in a small (sub‐bank‐full) flow event in an Australian desert stream

The behaviour of a discrete sub‐bank‐full flow event in a small desert stream in western NSW, Australia, is analysed from direct observation and sediment sampling during the flow event and from later channel surveys. The flow event, the result of an isolated afternoon thunderstorm, had a peak discharge of 9 m³/s at an upstream station. Transmission loss totally consumed the flow over the following 7·6 km. Suspended sediment concentration was highest at the flow front (not the discharge peak) and declined linearly with the log of time since passage of the flow front, regardless of discharge variation. The transmission loss responsible for the waning and eventual cessation of flow occurred at a mean rate of 13.2% per km. This is quite rapid, and is more than twice the corresponding figure for bank‐full flows estimated by Dunkerley (1992) on the same stream system. It is proposed that transmission losses in ephemeral streams of the kind studied may be minimized in flows near bank‐full stage, and be higher in both sub‐bank‐full and overbank flows. Factors contributing to enhanced flow loss in the sub‐bank‐full flow studied included abstractions of flow to pools, scour holes and other low points along the channel, and overflow abstractions into channel filaments that did not rejoin the main flow. On the other hand, losses were curtailed by the shallow depth of banks wetted and by extensive mud drapes that were set down over sand bars and other porous channel materials during the flow. Thus, in contrast with the relatively regular pattern of transmission loss inferred from large floods, losses from low flows exhibit marked spatial variability and depend to a considerable extent on streamwise variations in channel geometry, in addition to the depth and porosity of channel perimeter sediments. Copyright © 1999 John Wiley & Sons, Ltd.     

Fluvial suspended sediment transport from cold and warm-based glaciers in Svalbard

An analysis of temporal variability in proglacial suspended sediment concentration is undertaken using time series data collected from three Svalbard basins which include one largely cold-based glacier (Austre Brøggerbreen), one largely warm-based glacier (Finsterwalderbreen) and one intermediate polythermal glacier (Erdmannbreen). The temporal variability in proglacial suspended sediment concentration is analysed using multiple regression techniques in which discharge is supplemented by other predictors acting as surrogates for variability in sediment supply at diurnal, medium-term and seasonal timescales. These multiple regression models improve upon the statistical explanation of suspended sediment concentration produced by simple sediment rating curves but need to account for additional stochastic elements within the time series before they may be considered successful. An interpretation of the physical processes which are responsible for the regression model characteristics is offered as a basis for comparing the different arctic glaciofluvial suspended sediment transport systems with that of their better known temperate glaciofluvial counterparts. It is inferred that the largely warm-based glacier is dominated by sediment supply from subglacial reservoirs which evolve in a similar manner to temperate glaciers and which cause a pronounced seasonal exhaustion of suspended sediment supply. The largely cold-based glacier, however, is dominated by sediment supply from marginal sources which generate a responsive system at short time scales but no significant seasonal pattern. The intermediate polythermal glacier basin, which was anticipated to be similar to the warm-based glacier, instead shows a highly significant seasonal increase in suspended sediment supply from an unusual subglacial reservoir emerging under pressure in the glacier foreland. The temperate model of glaciofluvial suspended sediment transport is therefore found to be of limited use in an arctic context. Copyright © 1999 John Wiley & Sons, Ltd.     

Short‐term spatial and temporal patterns of suspended sediment transfer in proglacial channels,small River Glacier,Canada

Alpine glacial basins are a significant source and storage area for sediment exposed by glacial retreat. Recent research has indicated that short‐term storage and release of sediment in proglacial channels may control the pattern of suspended sediment transfer from these basins. Custom‐built continuously recording turbidimeters installed on a network of nine gauging sites were used to characterize spatial and temporal variability in suspended sediment transfer patterns for the entire proglacial area at Small River Glacier, British Columbia, Canada. Discharge and suspended sediment concentration were measured at 5 min intervals over the ablation season of 2000. Differences in suspended sediment transfer patterns were then extracted using multivariate statistics (principal component and cluster analysis). Results showed that each gauging station was dominated c. 80% of days by diurnal sediment transfer patterns and ‘low’ suspended sediment concentrations. ‘Irregular’ transfer patterns were generally associated with ‘high’ sediment concentrations during snowmelt and rainfall events, resulting in the transfer of up to 70% of the total seasonal suspended sediment load at some gauging stations. Suspended sediment enrichment of up to 600% from channel storage release and extrachannel inputs occurred between the glacial front and distal proglacial boundary. However, these patterns differed significantly between gauging stations as determined by the location of the gauging station within the catchment and meteorological conditions. Overall, the proglacial area was the source for up to 80% of the total suspended sediment yield transferred from the Small River Glacier basin. These results confirmed that sediment stored and released in the proglacial area, in particular from proglacial channels, was controlling suspended sediment transfer patterns. To characterize this control accurately requires multiple gauging stations with high frequency monitoring of suspended sediment concentration. Accurate characterization of this proglacial control on suspended sediment transfer may therefore aid interpretation of suspended sediment yield patterns from glacierized basins. Copyright © 2004 John Wiley & Sons, Ltd.     

Bacteria‐sediment associations in an alpine,freshwater environment and their effects on particle size,density and settling velocity

This study measures the presence of bacteria‐sediment associations (BSAs) in an alpine, glacier‐fed watershed in the Southern Coast Mountains of British Columbia, Canada. The impact of BSAs on the creation of flocculated particles and their settling velocity are quantified using a laser transmissometer. Results from the study indicate that BSAs are present in the watershed and vary over both space and time. The percentage of bacteria associated with sediment particles was found to range from < 1% to 40%. Major sources of planktonic bacteria such as agricultural land and wastewater treatment outflow co‐occur with large decreases in the BSA ratio. Laboratory analysis demonstrates that an increase in the concentration of bacteria was associated with a decrease in the volume concentration of small particles, and a decrease in both estimated density and measured settling velocity for particles in larger size classes; consistent with flocculated particles of increasing complexity arising from combinations of primary particles and/or BSAs. Paleoenvironmental reconstructions using laminated lake sediments in alpine, glacier‐fed systems benefit from a fuller understanding of the geomorphologic processes by which they formed. While bacteria are noted to enhance formation of flocculated particles in laboratory systems, their impact upon geomorphic processes in natural systems have yet to be fully explored. © 2018 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.     

Discharge and suspended sediment transport in the Ayeyarwady River,Myanmar: centennial and decadal changes

Among the large rivers rising on the Tibetan Plateau and adjacent high mountains, the discharge and suspended sediment load of the Ayeyarwady (Irrawaddy) River are the least well known. Data collected between 1969 and 1996 at Pyay (Prome) are analysed to provide the best available modern estimate of discharge (379 ± 47 × 10⁹ m³/year) and suspended sediment load (325 ± 57 × 10⁶ t/year) for the river upstream of the delta head. A statistical comparison with data collected in the nineteenth century (1871 to 1879) shows discharge has significantly decreased in the last ～100 years. Regression and correlation analyses between discharge in the modern period and indices of El Niño–Southern Oscillation (ENSO) show a relationship. Copyright © 2009 John Wiley & Sons, Ltd.     

Post‐wildfire changes in suspended sediment rating curves: Sabino Canyon,Arizona

Wildfire has been shown to increase erosion by several orders of magnitude, but knowledge regarding short‐term variations in post‐fire sediment transport processes has been lacking. We present a detailed analysis of the immediate post‐fire sediment dynamics in a semi‐arid basin in the southwestern USA based on suspended sediment rating curves. During June and July 2003, the Aspen Fire in the Coronado National Forest of southern Arizona burned an area of 343 km². Surface water samples were collected in an affected watershed using an event‐based sampling strategy. Sediment rating parameters were determined for individual storm events during the first 18 months after the fire. The highest sediment concentrations were observed immediately after the fire. Through the two subsequent monsoon seasons there was a progressive change in rating parameters related to the preferential removal of fine to coarse sediment. During the corresponding winter seasons, there was a lower supply of sediment from the hillslopes, resulting in a time‐invariant set of sediment rating parameters. A sediment mass‐balance model corroborated the physical interpretations. The temporal variability in the sediment rating parameters demonstrates the importance of storm‐based sampling in areas with intense monsoon activity to characterize post‐fire sediment transport accurately. In particular, recovery of rating parameters depends on the number of high‐intensity rainstorms. These findings can be used to constrain rapid assessment fire‐response models for planning mitigation activities. Copyright © 2006 John Wiley & Sons, Ltd.     

Predicting suspended sediment concentrations in the Meuse river using a supply‐based rating curve

A rating curve provides a reasonable estimate of the suspended sediment concentration at a given discharge. However, analysis of a detailed 9‐year time‐series of suspended sediment concentration (SSC) and discharge Q of the Meuse River in The Netherlands indicates that SSC is (besides discharge) controlled by exhaustion and replenishment of different sediment sources. Clockwise hysteresis and other effects of sediment exhaustion can be observed during and after flood events, and the effects of stockpiling of sediment in the river bed during low‐discharge periods are obvious in the SSC of the next flood. In a single regression equation we have implemented a parameter that represents the presence or absence of stock for sediment uptake. In comparison with a rating curve of SSC and Q, adding this parameter is shown to be a more reliable and comprehensive method to predict SSCs at all discharge regimes with all preceding discharge conditions, for single‐peaked and multi‐peaked runoff events as well as for low flow conditions. The method is probably applicable to other small‐ to medium‐scaled river basins. Copyright © 2007 John Wiley & Sons, Ltd.