Sample records for suspended sediment transport

  1. Distribution and transportation of suspended sediment

    International Nuclear Information System (INIS)

    Schubel, J.R.


    A number of studies of the distribution and character of suspended matter in the waters of the Atlantic shelf have documented the variations in the concentration of total suspended matter in both time and space. Very little is known, however, about the ultimate sources of inorganic suspended matter, and even less is known about the routes and rates of suspended sediment transport in shelf waters. Suspended particulate matter constitutes a potential vehicle for the transfer of energy-associated contaminants, radionuclides and oil, back to the coast and therefore to man. The concentrations of total suspended matter in shelf waters are typically so low, however, that the mechanism is ineffective. Studies of suspended particulate matter have a high scientific priority, but in this investigator's opinion the state of knowledge is adequate for preparation of the environmental impact statements that would be required for siting of offshore nuclear power plants and for oil drilling on the Atlantic Continental Shelf

  2. Simulation of suspended sediment transport initialized with satellite ...

    Indian Academy of Sciences (India)

    have described the effective use of satellite remote sensing data in modelling sediment transport. Quillon et al. (2004) have coupled remote sens- ing data with in situ measurements to simulate suspended sediment transport in New Caledonia. Lagoon. Initial distribution of sediment concentrations are of critical importance ...

  3. Simulation of suspended sediment transport initialized with satellite ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 121; Issue 5 ... Suspended sediment concentrations; OCM; sediment transport model; tide. ... Optimization of the model mud parameters, like settling velocity and critical shear stress for erosion are realized with respect to the sediment size distribution and the bottom ...

  4. Simulation of suspended sediment transport initialized with satellite ...

    Indian Academy of Sciences (India)

    vations are inadequate to understand the sedi- ment dispersion by the alternating tidal currents in regions like Gulf of Kachchh, while numerical. Keywords. Suspended sediment concentrations; OCM; sediment transport model; tide. J. Earth Syst. Sci. 121, No. 5, October 2012, pp. 1201–1213. cO Indian Academy of Sciences.

  5. Suspended sediment transport in the Gulf of Lions (NW Mediterranean): Impact of extreme storms and floods

    NARCIS (Netherlands)

    Ulses, C.; Estournel, C.; Durrieu de Madron, X.; Palanques, A.


    In situ observations were combined with 3D modeling to gain understanding of and to quantify the suspended sediment transport in the Gulf of Lions (NW Mediterranean Sea). The outputs of a hydrodynamic–sediment transport coupled model were compared to near-bottom current and suspended sediment

  6. On the influence of suspended sediment transport on the generation of offshore sand waves

    NARCIS (Netherlands)

    Sterlini-Van der Meer, Fenneke; Hulscher, Suzanne J.M.H.; van den Berg, J.; Geurts, Bernardus J.; Clercx, H.J.H.; Uijttewaal, Wim


    Sand waves are bed-forms occurring in shallow seas. Although their characteristics are mainly affected by bed load transport, during rough weather suspended sediment transport can influence their characteristics. As a first step to model these influences, we added suspended sediment transport to a

  7. Summertime Suspended Sediment Transport Patterns in the Partially-mixed Changjiang Estuary (United States)

    Niroomandi, A.; Ma, G.


    Sediment deposition in the Northern Passage of the Changjiang Estuary, where the Deepwater Navigation Channel (DNC) is located, has been a major concern in the past decades. To understand the sediment transport patterns and sediment sources in the navigational channel, field data on tidal flow and suspended sediment concentration are collected and analyzed in this study. It is shown that sediment transport processes are dominated by ebb currents. As a result, the total sediment flux is generally toward the ocean and the maximum value is found to be in the middle of the passage. At the mouth of the estuary, the total sediment flux is toward the river in the lower layer of the water column confirming a two-layer tide-averaged flow pattern in this region. The effects of sediment on stratification and mixing in the northern passage is examined by calculating eddy viscosity. Results show that strong mixing occurs during ebb in the upper reach of the passage where river discharge has high influence on the estuary. Suspended sediment can dampen turbulence and reduce mixing in the water column. To reveal the major suspended sediment sources, bed shear stresses over the entire passage are calculated. It is found that, during ebb, the bed shear stress is generally larger than the critical value for sediment suspension. Sediment in the water column is suspended from the bed. During flood, the suspended sediment in the northern passage are likely coming from a neighboring shoal, where the water depth is shallow and bed shear stress is large.

  8. Residual fluxes and suspended sediment transport in the lower reaches of Muvattupuzha River, southwest coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Revichandran, C.; Balachandran, K.K.; Xavier, J.K.; Rejendran, N.C.

    Spatial and seasonal variation of different physical processes governing the transport of salt and sediment of the Muvattupuzha River, in Kerala, India are discussed. Salt and suspended sediment due to tidal pumping was directed upstream, salt...

  9. Sediment and Fecal Indicator Bacteria Loading in a Mixed Land Use Watershed: Contributions from Suspended and Bed Load Transport (United States)

    Water quality studies that quantify sediment and fecal bacteria loading commonly focus on suspended contaminants transported during high flows. Fecal contaminants in bed sediments are typically ignored and need to be considered because of their potential to increase pathogen load...

  10. Temporal dynamics of suspended sediment transport in a glacierized Andean basin (United States)

    Mao, Luca; Carrillo, Ricardo


    Suspended sediment transport can affect water quality and aquatic ecosystems, and its quantification is of the highest importance for river and watershed management. Suspended sediment concentration (SSC) and discharge were measured at two locations in the Estero Morales, a Chilean Andean stream draining a small basin (27 km2) hosting glacierized areas of about 1.8 km2. Approximately half of the suspended sediment yield (470 t year- 1 km- 2) was transported during the snowmelt period and half during glacier melting. The hysteresis patterns between discharge and SSC were calculated for each daily hydrograph and were analysed to shed light on the location and activity of different sediment sources at the basin scale. During snowmelt, an unlimited supply of fine sediments is provided in the lower and middle part of the basin and hysteresis patterns tend to be clockwise as the peaks in SSC precede the peak of discharge in daily hydrographs. Instead, during glacier melting the source of fine sediments is the proglacial area, producing counterclockwise hysteresis. It is suggested that the analysis of hysteretic patterns over time provides a simple concept for interpreting variability of location and activity of sediment sources at the basin scale.

  11. Numerical Modelling of Suspended Transport and Deposition of Highway Deposited Sediments

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby; Larsen, Torben; Bach, Christine

    Good data for calibration and validation of numerical models are of high importance. In the natural environment data can be hard to archive and the stochastic nature have governing influence on the data archived. Hence for modelling of suspended transport and deposition of particles, originating...... from the highway surfaces, in highway detention ponds, four experiments are carried out. To simplify the complexity of a real pond and for easy control and measurement the sediment transports where carried out in two rectangular channels....

  12. Suspended sediment transport trough a large fluvial-tidal channel network (United States)

    Wright, Scott A.; Morgan-King, Tara L.


    The confluence of the Sacramento and San Joaquin Rivers, CA, forms a large network of interconnected channels, referred to as the Sacramento-San Joaquin Delta (the Delta). The Delta comprises the transition zone from the fluvial influences of the upstream rivers and tidal influences of San Francisco Bay downstream. Formerly an extensive tidal marsh, the hydrodynamics and geomorphology of Delta have been substantially modified by humans to support agriculture, navigation, and water supply. These modifications, including construction of new channels, diking and draining of tidal wetlands, dredging of navigation channels, and the operation of large pumping facilities for distribution of freshwater from the Delta to other parts of the state, have had a dramatic impact on the physical and ecological processes within the Delta. To better understand the current physical processes, and their linkages to ecological processes, the USGS maintains an extensive network of flow, sediment, and water quality gages in the Delta. Flow gaging is accomplished through use of the index-velocity method, and sediment monitoring uses turbidity as a surrogate for suspended-sediment concentration. Herein, we present analyses of the transport and dispersal of suspended sediment through the complex network of channels in the Delta. The primary source of sediment to the Delta is the Sacramento River, which delivers pulses of sediment primarily during winter and spring runoff events. Upon reaching the Delta, the sediment pulses move through the fluvial-tidal transition while also encountering numerous channel junctions as the Sacramento River branches into several distributary channels. The monitoring network allows us to track these pulses through the network and document the dominant transport pathways for suspended sediment. Further, the flow gaging allows for an assessment of the relative effects of advection (the fluvial signal) and dispersion (from the tides) on the sediment pulses as they

  13. Monitoring suspended sediment transport in an ice-affected river using acoustic Doppler current profilers (United States)

    Moore, S. A.; Ghareh Aghaji Zare, S.; Rennie, C. D.; Ahmari, H.; Seidou, O.


    Quantifying sediment budgets and understanding the processes which control fluvial sediment transport is paramount to monitoring river geomorphology and ecological habitat. In regions that are subject to freezing there is the added complexity of ice. River ice processes impact flow distribution, water stage and sediment transport. Ice processes typically have the largest impact on sediment transport and channel morphodynamics when ice jams occur during ice cover formation and breakup. Ice jams may restrict flow and cause local acceleration when released. Additionally, ice can mechanically scour river bed and banks. Under-ice sediment transport measurements are lacking due to obvious safety and logistical reasons, in addition to a lack of adequate measurement techniques. Since some rivers can be covered in ice during six months of the year, the lack of data in winter months leads to large uncertainty in annual sediment load calculations. To address this problem, acoustic profilers are being used to monitor flow velocity, suspended sediment and ice processes in the Lower Nelson River, Manitoba, Canada. Acoustic profilers are ideal for under-ice sediment flux measurements since they can be operated autonomously and continuously, they do not disturb the flow in the zone of measurement and acoustic backscatter can be related to sediment size and concentration. In March 2012 two upward-facing profilers (1200 kHz acoustic Doppler current profiler, 546 KHz acoustic backscatter profiler) were installed through a hole in the ice on the Nelson River, 50 km downstream of the Limestone Generating Station. Data were recorded for four months, including both stable cover and breakup periods. This paper presents suspended sediment fluxes calculated from the acoustic measurements. Velocity data were used to infer the vertical distribution of sediment sizes and concentrations; this information was then used in the interpretation of the backscattered intensity data. It was found that

  14. Transport of phosphorus, wash load and suspended sediment in the River Varde A in southwest Jutland, Denmark

    DEFF Research Database (Denmark)

    Thodsen, Hans; Hasholt, Bent; Pejrup, Morten


    Total phosphorus (TP) concentrations, suspended sediment concentrations (SSC) and wash load have been measured at three river monitoring stations in the River Varde Angstrom system since 1998. This provides the possibility of studying the link between SSC and wash load and concentrations of TP....... Transport rates of TP, suspended sediment and wash load at the three stations, calculated using rating curves, indicate the dependence of TP transport on the transport of suspended sediment and wash load. Two stations are located on tributaries flowing upstream of the third station located at a weir...... at the end of a small impoundment. Transport rates at the upstream stations were 57% higher for suspended sediment and 27% higher for wash load than at the downstream station, while transport of TP was the same. This indicates that phosphorus is transported adhered to the finest grain size fractions that do...

  15. Runoff and suspended sediment transport after plantation interventions in experimental catchments with contrasting rainfall conditions, Chile (United States)

    Iroume, A.; Schuller, P.; Bronstert, A.; Carey, P.; Palacios, H.; Ulloa, H.


    Experimental catchments located in sites with contrasting annual rainfall (Nacimiento, 37° 28" S, 72° 42" W, long term mean annual rainfall ~ 1,200 mm, and Los Ulmos, 40° 02" S, 73° 06" W, long term mean annual rainfall ~ 2,500 mm) are been monitored to study the long term effects of different forest plantation practices on runoff and suspended sediment transport. In each site, one control and one treatment catchment (12.6 and 7.7 ha in Nacimiento and 19.8 and 7.7 ha in Los Ulmos) are monitored. All the catchments are controlled by purpose-built V-notch weir gauging stations equipped with continuous water level recorders and suspended sediment is quantified in these stations from automatically collected integrated water samples. After a calibration period the plantation of one paired catchment in each site was clearfelled. Treated and control catchments will be from now on identified as NT and LUT and NC and LUT respectively. The Pinus radiata plantation in NT was clearfelled during the first half of April 2010, while the Eucalyptus globulus plantation in LUT was partially clearfelled in November 2009 and then completed in April 2010. After clearfelling runoff increases were observed in both harvested catchments as compared with the pre-treatment runoff trend between treatment and control catchments. In the Nacimiento site, mean monthly values for suspended sediment loads registered for the pre, during and post-treatment periods are not much different for NT and NC. For the pre-treatment period (April 2008 to March 2010), mean monthly suspended sediment loads were 12.8 kg/ha in NC and 16.2 kg/ha in NT, and 0.9 kg/ha in NC and 2.7 kg/ha in NT during the harvesting operations (April 2010). Mean monthly suspended sediment loads during the first year of the post-harvesting period (May to December 2010) were 69.9 kg/ha in NC and 59 kg/ha in NT and 0.9 kg/ha in NC and 6.2 kg/ha in NT during the year after clearfelling (January to June 2011). Year 2010 was extremely

  16. Suspended sediment transport in a semiarid watershed, Wadi Abd, Algeria (1973 1995) (United States)

    Achite, Mohamed; Ouillon, Sylvain


    SummaryA quantification of the fine sediment budget of a wadi (dryland river) in NW Algeria is presented for a period of 22 hydrological years (1973-1995). The climate is Mediterranean over the Wadi Abd basin (2480 km 2), the mean annual precipitation is 250 mm and the mean annual discharge is 1.0 m 3 s -1 at the gauging station. Regression relationships between water discharge Q and suspended sediment concentration C are calculated from 1432 paired measurements in the Wadi Abd, leading to power-law equations of the type C = a Qb. The variability of coefficients a and b, calculated for 138 floods and flood stages, is analyzed. The median value of b is 0.757, indicating that C is almost proportional to Q3/4. Given that the ( a, b) pairs are correctly aligned ( r2 = 0.578), the coefficients a and b are not independent. Regression relationships between daily Q and daily suspended sediment concentration and discharge Qs are calculated from 702 input data. The performances of these regression relationships are shown to be equivalent, leading to over-estimations of 20-25% of the suspended sediment flux. The non-biased C- Q sediment rating curve is used to extrapolate a time series of C measurements, and thus to analyze the long-term patterns in suspended sediment transport. Average sediment wash-down (136 t km -2 yr -1) is similar to the mean global value. The ratio of sediment wash-down to the river water discharge is 10.7 × 10 6 t km 3, 20 times greater than the average ratio in the Earth's eastern hemisphere, and illustrates the highly erosive power of wadis. Variability is shown to be significant at the seasonal scale (CV = 89%) and higher at the interannual scale (CV = 139%). The fine sediment flux mainly occurs in autumn (48.4%) and spring (32.7%). Although precipitation decreased, it was more irregular from one year to another over the period 1985-1995 than during the period 1973-1985, and the Wadi Abd, which was a perennial river, became intermittent in the late

  17. The role of suspension events in cross-shore and longshore suspended sediment transport in the surf zone (United States)

    Jaffe, Bruce E.


    Suspension of sand in the surf zone is intermittent. Especially striking in a time series of concentration are periods of intense suspension, suspension events, when the water column suspended sediment concentration is an order of magnitude greater than the mean concentration. The prevalence, timing, and contribution of suspension events to cross-shore and longshore suspended sediment transport are explored using field data collected in the inner half of the surf zone during a large storm at Duck, NC. Suspension events are defined as periods when the concentration is above a threshold. Events tended to occur during onshore flow under the wave crest, resulting in an onshore contribution to the suspended sediment transport. Even though large events occurred less than 10 percent of the total time, at some locations onshore transport associated with suspension events was greater than mean-current driven offshore-directed transport during non-event periods, causing the net suspended sediment transport to be onshore. Events and fluctuations in longshore velocity were not correlated. However, events did increase the longshore suspended sediment transport by approximately the amount they increase the mean concentration, which can be up to 35%. Because of the lack of correlation, the longshore suspended sediment transport can be modeled without considering the details of the intensity and time of events as the vertical integration of the product of the time-averaged longshore velocity and an event-augmented time-averaged concentration. However, to accurately model cross-shore suspended sediment transport, the timing and intensity of suspension events must be reproduced.

  18. Transport and Sources of Suspended Sediment in the Mill Creek Watershed, Johnson County, Northeast Kansas, 2006-07 (United States)

    Lee, Casey J.; Rasmussen, Patrick P.; Ziegler, Andrew C.; Fuller, Christopher C.


    The U.S. Geological Survey, in cooperation with the Johnson County Stormwater Management Program, evaluated suspended-sediment transport and sources in the urbanizing, 57.4 mi2 Mill Creek watershed from February 2006 through June 2007. Sediment transport and sources were assessed spatially by continuous monitoring of streamflow and turbidity as well as sampling of suspended sediment at nine sites in the watershed. Within Mill Creek subwatersheds (2.8-16.9 mi2), sediment loads at sites downstream from increased construction activity were substantially larger (per unit area) than those at sites downstream from mature urban areas or less-developed watersheds. Sediment transport downstream from construction sites primarily was limited by transport capacity (streamflow), whereas availability of sediment supplies primarily influenced transport downstream from mature urban areas. Downstream sampling sites typically had smaller sediment loads (per unit area) than headwater sites, likely because of sediment deposition in larger, less sloping stream channels. Among similarly sized storms, those with increased precipitation intensity transported more sediment at eight of the nine monitoring sites. Storms following periods of increased sediment loading transported less sediment at two of the nine monitoring sites. In addition to monitoring performed in the Mill Creek watershed, sediment loads were computed for the four other largest watersheds (48.6-65.7 mi2) in Johnson County (Blue River, Cedar, Indian, and Kill Creeks) during the study period. In contrast with results from smaller watersheds in Mill Creek, sediment load (per unit area) from the most urbanized watershed in Johnson County (Indian Creek) was more than double that of other large watersheds. Potential sources of this sediment include legacy sediment from earlier urban construction, accelerated stream-channel erosion, or erosion from specific construction sites, such as stream-channel disturbance during bridge

  19. Suspended-sediment transport from the Green-Duwamish River to the Lower Duwamish Waterway, Seattle, Washington, 2013–17 (United States)

    Senter, Craig A.; Conn, Kathleen E.; Black, Robert W.; Peterson, Norman; Vanderpool-Kimura, Ann M.; Foreman, James R.


    The Green-Duwamish River transports watershed-derived sediment to the Lower Duwamish Waterway Superfund site near Seattle, Washington. Understanding the amount of sediment transported by the river is essential to the bed sediment cleanup process. Turbidity, discharge, suspended-sediment concentration (SSC), and particle-size data were collected by the U.S. Geological Survey (USGS) from February 2013 to January 2017 at the Duwamish River, Washington, within the tidal influence at river kilometer 16.7 (USGS streamgage 12113390; Duwamish River at Golf Course at Tukwila, WA). This report quantifies the timing and magnitude of suspended-sediment transported in the Duwamish River. Regression models were developed between SSC and turbidity and SSC and discharge to estimate 15- minute SSC. Suspended-sediment loads were calculated from the computed SSC and time-series discharge data for every 15-minute interval during the study period. The 2014–16 average annual suspended-sediment load computed was 117,246 tons (106,364 metric tons), of which 73.5 percent or (86,191 tons; 78,191 metric tons) was fine particle (less than 0.0625 millimeter in diameter) suspended sediment. The seasonality of this site is apparent when you divide the year into "wet" (October 16– April 15) and "dry" (April 16–October 15) seasons. Most (97 percent) of the annual suspended sediment was transported during the wet season, when brief periods of intense precipitation from storms, large releases from the Howard Hanson Dam, or a combination of both were much more frequent.

  20. Suspended sediment transport and shoaling in the Munambam fishery harbour, Kerala

    Digital Repository Service at National Institute of Oceanography (India)

    Revichandran, C.; Abraham, P.; Josanto, V.; Sankaranarayanan, V.N.

    Results of the monthly synoptic field observations of vertical profiles of suspended sediment concentration, current velocity and salinity carried out in the Azhicode Estuary are presented with a view to understand the shoaling and siltation...

  1. Unified theory of non-suspended sediment transport mediated by a Newtonian fluid (United States)

    Pähtz, Thomas; Durán, Orencio


    We present a unified theory of steady, homogeneous, non-suspended transport of nearly uniform spheres mediated by an arbitrary Newtonian fluid. The theory consists of elements that are rigorously derived from Newton's axioms and of semi-empirical elements that well describe simulation data, obtained using a coupled DEM/RANS numerical model of sediment transport in a Newtonian fluid (Durán et al., POF 103306, 2012), for the entire simulated range of the particle-fluid-density ratio s=ρ_p/ρ_f, particle Reynolds number Re_p=√{(s-1)gd^3}/ν, and Shields number Θ=τ/[(ρ_p-ρ_f)gd], where g is the gravitational constant, d the mean particle diameter, and ν the kinematic viscosity. The theory takes into account our recent numerical finding that the mode of entrainment of bed sediment is controlled by the `impact number' Im=Re_p√{s+0.5} (, with entrainment through particle-bed impacts dominating most conditions (including turbulent bedload transport). Despite not being fitted to experimental data, the theory simultaneously reproduces measurements in air (s≈2100) and liquids (s≈1{-}5) of the transport cessation threshold Θ^ext (, obtained from extrapolation to vanishing transport, and the dimensionless value Q^\\ast=Q/(ρ_p√{(s-1)gd^3}) of the sediment transport rate Q. From the theory and simulations, we learn that considering added-mass, lubrication, fluid lift, and/or history forces is not required to quantitatively reproduce measurements. However, collisions between transported particles cannot be neglected as they are strongly influencing the scaling of Q_\\ast with Θ. We find such collisions are behind the asymptotic scaling Q_\\ast∝Θ^3Rep measured for transport in viscous liquids and also indirectly behind a transition from a linear scaling Q_\\ast∝√{Θ^ex_t}(Θ-Θ^ex_t) to a non-linear scaling Q_\\ast∝√{Θ}(Θ-Θ^ex_t) of the transport rate in turbulent bedload and

  2. A regional sediment transport modeling for fluvial influx and redistribution of suspended radionuclide in the Fukushima coast

    International Nuclear Information System (INIS)

    Uchiyama, Yusuke; Yamanishi, Takafumi; Tsumune, Daisuke; Miyazawa, Yasumasa


    Fluvial discharge from the rivers is viewed as a missing piece for the inventory of the radionuclides in the ocean during the accident at the Fukushima Daiichi Nuclear Power Plant. The land-derived input introduces a time lag behind the direct release through hydrological process because these radionuclides mostly attach to suspended particles (sediments) that are transported quite differently to the dissolved matter in the ocean. We therefore develop a regional sediment transport model consisting of a multi-class non-cohesive sediment transport module, a wave-enhanced bed boundary layer model and a stratigraphy model proposed by Blaas et al. (2007) based on ROMS. (author)

  3. Impacts of Land-Cover Change on Suspended Sediment Transport in Two Agricultural Watersheds (United States)

    Schilling, K.E.; Isenhart, T.M.; Palmer, J.A.; Wolter, C.F.; Spooner, J.


    Suspended sediment is a major water quality problem, yet few monitoring studies have been of sufficient scale and duration to assess the effectiveness of land-use change or conservation practice implementation at a watershed scale. Daily discharge and suspended sediment export from two 5,000-ha watersheds in central Iowa were monitored over a 10-year period (water years 1996-2005). In Walnut Creek watershed, a large portion of land was converted from row crop to native prairie, whereas in Squaw Creek land use remained predominantly row crop agriculture. Suspended sediment loads were similar in both watersheds, exhibiting flashy behavior typical of incised channels. Modeling suggested that expected total soil erosion in Walnut Creek should have been reduced 46% relative to Squaw Creek due to changes in land use, yet measured suspended sediment loads showed no significant differences. Stream mapping indicated that Walnut Creek had three times more eroding streambank lengths than did Squaw Creek suggesting that streambank erosion dominated sediment sources in Walnut Creek and sheet and rill sources dominated sediment sources in Squaw Creek. Our results demonstrate that an accounting of all sources of sediment erosion and delivery is needed to characterize sediment reductions in watershed projects combined with long-term, intensive monitoring and modeling to account for possible lag times in the manifestation of the benefits of conservation practices on water quality. ?? 2011 American Water Resources Association.

  4. Numerical Simulation of Suspended Sediment Transportation Based on Particle Tracking Model (United States)

    Yao, W. W.; Ying, C.; Mu, J. B.


    Coastal engineering that carried out on the muddy seabed were always accompanied by diffusion of suspended sediment, and that would impact on the surrounding marine environment. A 2-D tidal flow mathematical model of the Yueqing Bay was established based on the Lagrange particle tracking model, the diffusion of suspended sediment in pile foundation construction process of a new wharf in the Yueqing Bay was simulated through a continuous moving points method, the calculation results were compared with the one calculated by the traditional convection diffusion method, it showed that the results calculated from the two different methods were similar, therefore it proved the suitability of the Lagrange particle tracing model in the suspended sediment diffusion problems.

  5. The use of modeling and suspended sediment concentration measurements for quantifying net suspended sediment transport through a large tidally dominated inlet (United States)

    Erikson, Li H.; Wright, Scott A.; Elias, Edwin; Hanes, Daniel M.; Schoellhamer, David H.; Largier, John; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.


    Sediment exchange at large energetic inlets is often difficult to quantify due complex flows, massive amounts of water and sediment exchange, and environmental conditions limiting long-term data collection. In an effort to better quantify such exchange this study investigated the use of suspended sediment concentrations (SSC) measured at an offsite location as a surrogate for sediment exchange at the tidally dominated Golden Gate inlet in San Francisco, CA. A numerical model was calibrated and validated against water and suspended sediment flux measured during a spring–neap tide cycle across the Golden Gate. The model was then run for five months and net exchange was calculated on a tidal time-scale and compared to SSC measurements at the Alcatraz monitoring site located in Central San Francisco Bay ~ 5 km from the Golden Gate. Numerically modeled tide averaged flux across the Golden Gate compared well (r2 = 0.86, p-value

  6. Processes affecting suspended sediment transport in the mid-field plume region of the Rhine River, Netherlands. (United States)

    Flores, R. P.; Rijnsburger, S.; Horner-Devine, A.; Souza, A. J.; Pietrzak, J.


    This work will describe dominant processes affecting suspended sediment transport along the Dutch coast, in the mid-field plume region of the Rhine River. We will present field observations from two long-term deployments conducted in the vicinity of the Sand Engine, a mega-nourishment experiment located 10 km north of the Rhine river mouth. To investigate the role of density stratification, winds, tides, waves and river plume processes on sediment transport, frames and moorings were deployed within the excursion of the tidal plume front generated by the freshwater outflow from the Rhine River for 4 and 6 weeks during years 2013 and 2014, respectively. The moorings were designed to measure vertical profiles of suspended sediment concentration (SSC) and salinity, using arrays of CTDs and OBS sensors. Mean tidal velocities were measured using bottom-mounted ADCPs. The near-bed dynamics and the near-bottom sediment concentrations were measured as well using a set of synchronized ADVs and OBSs. By combining the two deployments we observe hydrodynamics and suspended sediment dynamics under a wide range of forcing conditions. Preliminary observations indicate that stratification is highly dependent on wind magnitude and direction, and its role is primarily identified as to induce significant cross-shore sediment transport product of the generation of cross-shore velocities due to the modification of the tidal ellipses and the passage of the surface plume front. The passage of the surface plume front generates strong offshore currents near the bottom, producing transport events that can be similar in magnitude to the dominant alongshore transport. Preliminary results also indicate that storms play an important role in alongshore transport primarily by wave-induced sediment resuspension, but as stratification is suppressed due to the enhancement of mixing processes, no significant cross-shore transport is observed during very energetic conditions.

  7. Suspended sediment concentration and particle size distribution ...

    Indian Academy of Sciences (India)

    , zinc and nickel) transported in ... Suspended sediment concentration; heavy metal concentration; regression model; particle size distribution;. Kojour watershed; Iran. ..... contaminants in a uranium mine pite–Lake; Water Res. 39 3055–3061.

  8. The Effect of Suspended Sediment Transport and Deposition on Streambed Clogging Under Losing and Gaining Flow Conditions (United States)

    Fox, A.; Packman, A. I.; Preziosi-Ribero, A.; Li, A.; Arnon, S.


    Sediment transport and deposition in streams can affect streambed hydraulic characteristics due to clogging, reduce water fluxes through the hyporheic zone, and thus expected to affect biogeochemical processes. Processes affecting deposition of suspended particles were systematically studied under various overlying velocities but without taking into account the interactions with groundwater. This is despite the fact that the interaction with groundwater were shown to play an important role in deposition patterns of fine sediments in field studies. The objective of this study was to evaluate the effect of losing and gaining fluxes on suspended sediment depositional patterns and on hyporheic exchange fluxes. Experiments were conducted in a laboratory flume system (640 cm long and 30 cm wide) that has a capacity to enforce losing or gaining flow conditions. The flume was packed with homogenous sand, while suspended sediment deposition was evaluated by adding kaolinite particles to the water and following the deposition rate by particle disappearance from the bulk water. Consecutive additions of kaolinite were done, while hyporheic exchange fluxes were evaluated by conducting NaCl tracer experiments between each kaolinite additions. Furthermore, dye injections were used to visualize the flow patterns in the streambed using time-lapse photography through the transparent sidewalls of the flume. Hyporheic exchange and particle tracking simulations were done to assess the results of particle deposition and feedbacks between hyporheic flow, particle transport, and streambed clogging. Experimental results showed that the deposition of clay decreases with increasing amount of clay concentration in the sediment. Hyporheic exchange flux decreases linearly with increasing amount of clay added to the system and the region of active hyporheic exchange was confined to the upper part of the sediment. Understanding the particle deposition mechanisms under losing and gaining flow

  9. Fingerprint methods for suspended sediment transport processes by using X-ray fluorescence analysis (United States)

    Nakayama, K.; Beitia, C.; Ohtsu, N.; Yamasaki, S.; Yasuyuki, M.; Yamane, M.


    Suspended sediment (SS) can have significant impacts on ecological system, and high SS concentration can have significant impacts on human life. In the previous studies, radionuclide analysis has been applied to evaluate the production of SS in the river basins, which demonstrated that the surface soil erosion can be estimated by using radionuclide Pb-210ex. However, radionuclide analysis cannot indicate the relative amounts of SS transported from each individual sub-basin to the downstream end. Thus, X-ray Fluorescence Analysis (XRF Analysis) can be considered as an alternative method to radionuclide analysis because the XRF Analysis can measure 21 chemical compositions, Na2O, MgO, Al2O3, SiO2, P2O5, SO3, Cl, K2O, CaO, TiO2, Cr2O3, MnO, Fe2O3, Co2O3, NiO, CuO, ZnO, Rb2O, SrO, BaO, and Y2O3 by using X-ray Fluorescence Analyzer. In June of 2007, high turbidity, which is more than 10,000 (NTU), was measured in the Oromushi River basin of Hokkaido in Japan. Therefore, this study aims to clarify the mechanism of the transport of SS in the Oromushi River basin. We measured chemical compositions of soil with diameter less than 63 μm in the Oromushi River basin in order to pay attention to SS by using XRF. The Principal Component Analysis revealed that SiO2, Al2O3, Fe2O3, CaO and Na2O are the dominant chemical compositions. Although the predominant composition was the same in a river basin including the downstream end, significant differences were found in the pattern of chemical compositions. Therefore, by using the chemical compositions of SiO2, Al2O3, Fe2O3, CaO and Na2O, the Mixing Stable Isotope Analysis in R model (MixSIAR) based on Bayesian statistics was applied to estimate the transportation rate of SS from each sub-basin to the downstream end, which agreed with the field experiment results very well. As a result, spatial patterns of SS transportation rate are found to be strongly related to surface soil type.

  10. Longshore suspended sediment transport and its implications for submarine erosion off the Yangtze River Estuary (United States)

    Deng, Bing; Wu, Hui; Yang, Shilun; Zhang, Jing


    Coastal currents that originate from large rivers play a key role in delivering sediment to shelf regions. Quantifying their transport capability is therefore essential to understanding the sediment budgets and the consequent deposition or erosion of coastal areas. In February 2012, we observed the sediment transport carried by the Min-Zhe Coastal Current that originates from the Yangtze River mouth and calculated a flux of 18.7 tons per second on a cross-shore section. In this period the coastal current was at a typical status, which allowed us to estimate a total annual sediment transport of 0.27billion tons southward. This result was more than three times the present annual Yangtze River sediment discharge, suggesting that considerable net sediment removal occurs in the coastal regions. The sediment transport 0.27 billion tons/year is probably the deposition/erosion threshold for the East China Sea coast north of our study site. Analysis of historical Yangtze River sediment influx records showed, that the onset and acceleration of coastal erosion was closely linked with the operation of the Three Gorges Dam (TGD) upstream of the Yangtze River.

  11. Suspended-sediment inflows to Watts Bar Reservoir. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, L.K.


    Suspended-sediment inflows to Watts Bar Reservoir are important data that are required in numerical modeling of transport and deposition of sediment in the reservoir. Acceptable numerical modeling requires sediment inflow rates and locations in order to be able to compute the location and quantity of sediment deposited within the reservoir. Therefore, the representativeness of modeling results is highly dependent on the characteristics of sediment input to the model. The following recommendations, that account for suspended-sediment inflows to be used in the numerical modeling of sediment transport and deposition in Watts Bar Reservoir, were developed through an evaluation of available watershed and sediment deposition data. (1) Use the suspended-sediment rating regression equations of Gaydos et al., for Emory River at Oakdale, TN, and for Poplar Creek near Oak Ridge, TN, to represent the suspended-sediment inflows into Watts Bar Reservoir from its tributaries; (2) Use a suspended-sediment rating regression equation that was derived from suspended-sediment and streamflow data of the Little Tennessee River at McGhee, TN, to represent sediment inflow from the Little Tennessee River for simulation of any historical year before the completion of Tellico Dam; (3) Check the appropriateness of any assumption for suspended-sediment inflows from upstream reservoirs by using its long-term relationship to local suspended-sediment inflows and to the suspended-sediment outflow through Watts Bar Dam; and (4) Focus refinements to suspended-sediment inflow rates on the Clinch arm of Watts Bar Reservoir.

  12. Suspended sediment transport in the Deepwater Navigation Channel, Yangtze River Estuary, China, in the dry season 2009: 2. Numerical simulations (United States)

    Song, Dehai; Wang, Xiao Hua


    A three-dimensional wave-current-sediment coupled numerical model with wetting and drying process is developed to understand hydrodynamics and sediment transport dynamics in the Deepwater Navigation Channel (DNC), the North Passage of the Yangtze River Estuary (YRE), China. The model results are in good agreement with observed data, and statistics show good model skill scores and correlation coefficients. The model well reproduces the spring-neap variation between a well-mixed estuary and a highly stratified estuary. Model results indicate that the estuarine gravitational circulation plays the most important role in the estuarine turbidity maximum (ETM) formation in the DNC. The upstream nonlocal sediment intrusion through the spillover mechanism is a major source of sediment trapping in the North Passage after the morphological changes. Numerical studies are conducted to show scenarios in the YRE under the effects of different forcings (river discharges, waves, and winds). Between these study cases, surface-wave-breaking relieves the sediment trapping and bottom-wave-current-interaction aggravates the bed erosion and elevates the SSC in the ETM; the former and the latter have the least and largest influence on the suspended sediment transport in the DNC. The wind effects have a greater influence on sediment trapping than the river discharges, and the steady northwesterly wind condition favors the siltation in the DNC most. The significance of density-driven turbidity current is also assessed, which can enhance the saline-water intrusion and suppress the turbulent mixing in the bottom boundary layer.

  13. An inversion of the estuarine circulation by sluice water discharge and its impact on suspended sediment transport (United States)

    Schulz, Kirstin; Gerkema, Theo


    The Wadden Sea is characterized by a complex topography of branching channels and intertidal flats, in which the interplay between fresh water discharges, wind forcing and the tidal current causes sediment transport rates and direction to be highly variable in space and time. During three field campaigns, indications of a negative estuarine circulation have been found in a channel adjacent to the coast in the Western Dutch Wadden Sea. Contrary to the classical picture of estuarine circulation, a periodic density stratification was observed that builds up during flood and breaks down during ebb. This can be related to a large freshwater source at the mouth of the channel, the sluice in Kornwerderzand. In this study, observations of this phenomenon are presented, and with the help of a numerical model the different drivers for residual suspended matter transport in this area, namely tidal asymmetries in the current velocity and the above mentioned periodic stratification, are investigated. It is found that the residual current in the area of interest points in ebb direction, caused by both the elongated ebb flow phase and the periodic stratification. On the contrary, the stronger flood currents cause a transport of suspended matter in flood direction. This transport is counteracted and therefore diminished by the effects of the sluice discharge.

  14. Two-dimensional Lagrangian simulation of suspended sediment (United States)

    Schoellhamer, David H.


    A two-dimensional laterally averaged model for suspended sediment transport in steady gradually varied flow that is based on the Lagrangian reference frame is presented. The layered Lagrangian transport model (LLTM) for suspended sediment performs laterally averaged concentration. The elevations of nearly horizontal streamlines and the simulation time step are selected to optimize model stability and efficiency. The computational elements are parcels of water that are moved along the streamlines in the Lagrangian sense and are mixed with neighboring parcels. Three applications show that the LLTM can accurately simulate theoretical and empirical nonequilibrium suspended sediment distributions and slug injections of suspended sediment in a laboratory flume.

  15. Particle Tracking Model for Suspended Sediment Transport and Streambed Clogging Under Losing and Gaining Conditions (United States)

    Preziosi-Ribero, A.; Fox, A.; Packman, A. I.; Escobar-Vargas, J.; Donado-Garzon, L. D.; Li, A.; Arnon, S.


    Exchange of mass, momentum and energy between surface water and groundwater is a driving factor for the biology, ecology and chemistry of rivers and water bodies in general. Nonetheless, this exchange is dominated by different factors like topography, bed morphology, and large-scale hydraulic gradient. In the particular case of fine sediments like clay, conservative tracer modeling is impossible because they are trapped in river beds for long periods, thus the normal advection dispersion approach leads to errors and results do not agree with reality. This study proposes a numerical particle tracking model that represents the behavior of kaolinite in a sand flume, and how its deposition varies according to different flow conditions, namely losing and gaining flow. Since fine particles do not behave like solutes, kaolinite dynamics are represented using settling velocity and a filtration coefficient allowing the particles to be trapped in the bed. This approach allows us to use measurable parameters directly related with the fine particle features as size and shape, and hydraulic parameters. Results are then compared with experimental results from lab experiments obtained in a recirculating flume, in order to assess the impact of losing and gaining conditions on sediment transport and deposition. Furthermore, our model is able to identify the zones where kaolinite deposition concentrates over the flume due to the bed geometry, and later relate these results with clogging of the bed and hence changes in the bed's hydraulic conductivity. Our results suggest that kaolinite deposition is higher under losing conditions since the vertical velocity of the flow is added to the deposition velocity of the particles modeled. Moreover, the zones where kaolinite concentrates varies under different flow conditions due to the difference in pressure and velocity in the river bed.

  16. Suspended-sediment transport and storage: A demonstration of acoustic methods in the evaluation of reservoir management strategies for a small water-supply reservoir in western Colorado (United States)

    Williams, Cory A.; Richards, Rodney J.; Collins, Kent L.


    The U.S. Bureau of Reclamation (USBR) and local stakeholder groups are evaluating reservoir-management strategies within Paonia Reservoir. This small reservoir fills to capacity each spring and requires approximately half of the snowmelt-runoff volume from its sediment-laden source waters, Muddy Creek. The U.S. Geological Survey is currently conducting high-resolution (15-minute data-recording interval) sediment monitoring to characterize incoming and outgoing sediment flux during reservoir operations at two sites on Muddy Creek. The high-resolution monitoring is being used to establish current rates of reservoir sedimentation, support USBR sediment transport and storage models, and assess the viability of water-storage recovery in Paonia Reservoir. These sites are equipped with in situ, single-frequency, side-looking acoustic Doppler current meters in conjunction with turbidity sensors to monitor sediment flux. This project serves as a demonstration of the capability of using surrogate techniques to predict suspended-sediment concentrations in small streams (less than 20 meters in width and 2 meters in depth). These two sites provide the ability to report near real-time suspended-sediment concentrations through the U.S. Geological Survey National Water Information System (NWIS) web interface and National Real-Time Water Quality websites (NRTWQ) to aid in reservoir operations and assessments.

  17. Sediment Transport

    DEFF Research Database (Denmark)

    Liu, Zhou

    Flow and sediment transport are important in relation to several engineering topics, e.g. erosion around structures, backfilling of dredged channels and nearshore morphological change. The purpose of the present book is to describe both the basic hydrodynamics and the basic sediment transport...... mechanics. Chapter 1 deals with fundamentals in fluid mechanics with emphasis on bed shear stress by currents, while chapter 3 discusses wave boundary layer theory. They are both written with a view to sediment transport. Sediment transport in rivers, cross-shore and longshore are dealt with in chapters 2...

  18. Effect of algae on flocculation of suspended bed sediments in a large shallow lake. Consequences for ecology and sediment transport processes (United States)

    de Lucas Pardo, Miguel Angel; Sarpe, Dirk; Winterwerp, Johan Christian


    Lake Markermeer, a large shallow lake in The Netherlands, suffers from turbidity and ecology problems. As part of a study aiming to mitigate these problems, we study flocculation processes in the lake; in particular, the possible mutual flocculation between algae and re-suspended bed sediments. We show that sediment re-suspended from the bed of the lake can flocculate, forming flocs for which size is a function of the turbulence level in the water column. Moreover, we also demonstrate that algae and re-suspended bed sediments can mutually flocculate, yielding organic-inorganic aggregates. These aggregates have different features to those of their individual components, some of which have been measured and characterized in this paper. Furthermore, the characteristics of the resulting organic-inorganic flocs are strongly influenced by the type of algae in the aggregate. We found that, in the case of flocs consisting of bed sediments and filamentous algae, flocculation yields smaller flocs than for bed sediments only, resulting in an increased turbidity in the water column. In the case of flocs consisting of bed sediments and colonial algae, flocs grow faster and become larger than bed sediment flocs, which may result in the depletion of most colonies from the water column.

  19. Measuring suspended sediment in small mountain streams (United States)

    Robert B. Thomas


    Measuring suspended sediment concentration in streams provides a way of monitoring the effects of forest management activities on water quality. Collecting data on suspended sediment is an act of sampling. The nature of the delivery process and the circumstances under which data are collected combine to produce highly variable results that are difficult to analyze and...

  20. Temperature signal in suspended sediment export from an Alpine catchment (United States)

    Costa, Anna; Molnar, Peter; Stutenbecker, Laura; Bakker, Maarten; Silva, Tiago A.; Schlunegger, Fritz; Lane, Stuart N.; Loizeau, Jean-Luc; Girardclos, Stéphanie


    Suspended sediment export from large Alpine catchments ( > 1000 km2) over decadal timescales is sensitive to a number of factors, including long-term variations in climate, the activation-deactivation of different sediment sources (proglacial areas, hillslopes, etc.), transport through the fluvial system, and potential anthropogenic impacts on the sediment flux (e.g. through impoundments and flow regulation). Here, we report on a marked increase in suspended sediment concentrations observed near the outlet of the upper Rhône River Basin in the mid-1980s. This increase coincides with a statistically significant step-like increase in basin-wide mean air temperature. We explore the possible explanations of the suspended sediment rise in terms of changes in water discharge (transport capacity), and the activation of different potential sources of fine sediment (sediment supply) in the catchment by hydroclimatic forcing. Time series of precipitation and temperature-driven snowmelt, snow cover, and ice melt simulated with a spatially distributed degree-day model, together with erosive rainfall on snow-free surfaces, are tested to explore possible reasons for the rise in suspended sediment concentration. We show that the abrupt change in air temperature reduced snow cover and the contribution of snowmelt, and enhanced ice melt. The results of statistical tests show that the onset of increased ice melt was likely to play a dominant role in the suspended sediment concentration rise in the mid-1980s. Temperature-driven enhanced melting of glaciers, which cover about 10 % of the catchment surface, can increase suspended sediment yields through an increased contribution of sediment-rich glacial meltwater, increased sediment availability due to glacier recession, and increased runoff from sediment-rich proglacial areas. The reduced extent and duration of snow cover in the catchment are also potential contributors to the rise in suspended sediment concentration through

  1. Suspended sediment transport in the Deepwater Navigation Channel, Yangtze River Estuary, China, in the dry season 2009: 1. Observations over spring and neap tidal cycles (United States)

    Song, Dehai; Wang, Xiao Hua; Cao, Zhenyi; Guan, Weibing


    The in situ data in the Deepwater Navigation Channel (DNC), Yangtze River Estuary (YRE), China, in the dry season 2009, shows spring tides associated with greater maximum velocities, more mixing, less stratification, and diffused fluid mud; whereas neap tides are associated with smaller maximum velocities, greater stratification, inhibited mixing, and stratified fluid muds. The balance of salt flux indicates the seaward salt transport is dominated by fluvial flows, and the landward salt transport is generated by compensation flows during spring tides, but shear effects during neap tidal cycles. The balance of suspended sediment flux illustrates the offshore sediment transport is dominated by fluvial flows as well, but the onshore transport is induced by tidal-pumping effects on spring tides, and shear effects on neaps. The suspended sediment transport is strongly affected by the salinity distribution and salinity-gradient-induced stratification in the DNC. The spring-neap asymmetry is generated by the estuarine gravitational circulation during low-flow conditions; while the flood-ebb asymmetric stratification within a tidal cycle is due to the semidiurnal tidally movement of the salt front.

  2. Effect of algae on flocculation of suspended bed sediments in a large shallow lake. Consequences for ecology and sediment transport processes

    NARCIS (Netherlands)

    de Lucas Pardo, MiguelAngel; Sarpe, Dirk; Winterwerp, JohanChristian


    Lake Markermeer, a large shallow lake in The Netherlands, suffers from turbidity and ecology problems. As part of a study aiming to mitigate these problems, we study flocculation processes in the lake; in particular, the possible mutual flocculation between algae and re-suspended bed sediments. We

  3. Estimated Loads of Suspended Sediment and Selected Trace Elements Transported through Milltown Reservoir in the Upper Clark Fork Basin, Montana, Water Years 2004-07 (United States)

    Lambing, John H.; Sando, Steven K.


    The purpose of this report is to present estimated daily and annual loads of suspended sediment and selected trace elements for water years 2004-07 at two sites upstream and one site downstream from Milltown Reservoir. Milltown Reservoir is a National Priorities List Superfund site in the upper Clark Fork basin of western Montana where sediments enriched in trace elements from historical mining and ore processing have been deposited since the construction of Milltown Dam in 1907. The estimated loads were used to quantify annual net gains and losses (mass balance) of suspended sediment and trace elements within Milltown Reservoir before and after June 1, 2006, which was the start of Stage 1 of a permanent drawdown of the reservoir in preparation for removal of Milltown Dam. This study was done in cooperation with the U.S. Environmental Protection Agency. Daily loads of suspended sediment were estimated for water years 2004-07 by using either high-frequency sampling as part of daily sediment monitoring or regression equations relating suspended-sediment discharge to streamflow. Daily loads of unfiltered-recoverable arsenic, cadmium, copper, iron, lead, manganese, and zinc were estimated by using regression equations relating trace-element discharge to suspended-sediment discharge. Regression equations were developed from data for eriodic water-quality samples collected during water years 2004-07. The equations were applied to daily records of either streamflow or suspended-sediment discharge to produce estimated daily loads. Variations in daily suspended-sediment and trace-element loads generally coincided with variations in streamflow. For most of the period before June 1, 2006, differences in daily loads transported to and from Milltown Reservoir were minor or indicated small amounts of deposition; however, losses of suspended sediment and trace elements from the reservoir occurred during temporary drawdowns in July-August 2004 and October-December 2005. After the

  4. Suspended sediments of the modern Amazon and Orinoco rivers (United States)

    Meade, R.H.


    The Amazon and Orinoco Rivers are massive transcontinental conveyance systems for suspended sediment. They derive about 90% of their sediment from the Andes that support their western headwaters, transport it for thousands of kilometers across the breadth of the continent and deposit it in the coastal zones of the Atlantic. At their points of maximum suspended-sediment discharge, the Amazon transports an average of 1100-1300 ?? 106 tons per year and the Orinoco transports about 150 ?? 106 tons per year. Relations of sediment discharge to water discharge are complicated by unusual patterns of seasonal storage and remobilization, increased storage and reduced transport of sediment in the middle Orinoco during periods of peak water discharge, and storage of suspended sediment in the lower Amazon during rising discharge and resuspension during falling discharge. Spatial distributions of suspended sediment in cross-sections of both rivers are typically heterogeneous, not only in the vertical sense but also in the lateral. The cross-channel mixing of tributary inputs into the mainstem waters is a slow process that requires several hundred kilometers of downriver transport to complete. Considerable fine-grained sediment is exchanged between rivers and floodplains by the combination of overbank deposition and bank erosion. ?? 1994.

  5. Fluvial geomorphology and suspended-sediment transport during construction of the Roanoke River Flood Reduction Project in Roanoke, Virginia, 2005–2012 (United States)

    Jastram, John D.; Krstolic, Jennifer L.; Moyer, Douglas; Hyer, Kenneth


    Beginning in 2005, after decades of planning, the U.S. Army Corps of Engineers (USACE) undertook a major construction effort to reduce the effects of flooding on the city of Roanoke, Virginia—the Roanoke River Flood Reduction Project (RRFRP). Prompted by concerns about the potential for RRFRP construction-induced geomorphological instability and sediment liberation and the detrimental effects these responses could have on the endangered Roanoke logperch (Percina rex), the U.S. Geological Survey (USGS) partnered with the USACE to provide a real-time warning network and a long-term monitoring program to evaluate geomorphological change and sediment transport in the affected river reach. Geomorphological change and suspended-sediment transport are highly interdependent and cumulatively provide a detailed understanding of the sedimentary response, or lack thereof, of the Roanoke River to construction of the RRFRP.

  6. Spatial and temporal variability in the concentration and speciation of metals in suspended sediment transported by the River Aire, Yorkshire, UK (United States)

    Carter, Julie; Walling, Desmond E.; Owens, Philip N.; Leeks, Graham J. L.


    In recent years, there has been an increasing awareness of the important role of fine sediment in the transport and storage of metals in fluvial systems. However, there has been little research on the behaviour of contaminated sediment in industrial rivers in the UK. This paper examines spatial and temporal variations in the concentration and speciation of lead, copper and chromium associated with suspended sediment in the River Aire in Yorkshire, UK. An increase in the total concentration of all three metals in sediment was identified in the lower reaches, which reflected inputs of road dust, sewage and industrial effluents. Spatial variations in the chemical speciation of the metals were also identified. The iron-manganese oxides and organic fractions were the most significant for the adsorption of metals by sediment. Both the concentrations and speciation of sediment-associated metals exhibited substantial temporal variation. Such variation reflected the accumulation of metals and organic matter on the river-bed during low flows, the subsequent remobilization of the sediment at high flows and the additional supply of sediment from uncontaminated and contaminated sources, including pulse inputs of road dust, sewage and industrial effluent. The findings presented have important implications for the development of effective catchment management strategies for the control of point- and diffuse-source pollution.

  7. Effects of urban best management practices on streamflow and phosphorus and suspended-sediment transport on Englesby Brook in Burlington, Vermont, 2000-2010 (United States)

    Medalie, Laura


    An assessment of the effectiveness of several urban best management practice structures, including a wet extended detention facility and a shallow marsh wetland (together the "wet extended detention ponds"), was made using data collected from 2000 through 2010 at Englesby Brook in Burlington, Vermont. The purpose of the best management practices was to reduce high streamflows and phosphorus and suspended-sediment loads and concentrations and to increase low streamflows. Englesby Brook was monitored for streamflow, phosphorus, and suspended-sediment concentrations at a streamgage downstream of the best management practice structures for 5 years before the wet extended detention ponds were constructed in 2005 and for 4 years (phosphorus and suspended-sediment concentrations) or 5 years (streamflow) after they were constructed. The period after construction of the best management practice structures was wetter and had higher discharges than the period before construction. Despite the wetter conditions, streamflow duration curves provided evidence that the streamflow regime appeared to have shifted so that the percentages of low streamflows have increased and those of high streamflows may have slightly decreased. Two other hydrologic measures showed improvements in the years following construction of the best management practices: the percentage of annual discharge transported during the 3 days with highest discharges and the number of days with zero streamflow have both decreased. Evidence was mixed for the effectiveness of the best management practices in reducing phosphorus and suspended-sediment concentrations and loads. Annual phosphorus and suspended-sediment loads, monthly loads, low-streamflow concentrations, storm-averaged streamflow-adjusted concentrations, and total storm loads either did not change significantly or increased in the period after construction. These results likely were because of the wetter conditions in the period after construction. For

  8. Improving suspended sediment measurements by automatic samplers. (United States)

    Gettel, Melissa; Gulliver, John S; Kayhanian, Masoud; DeGroot, Gregory; Brand, Joshua; Mohseni, Omid; Erickson, Andrew J


    Suspended solids either as total suspended solids (TSS) or suspended sediment concentration (SSC) is an integral particulate water quality parameter that is important in assessing particle-bound contaminants. At present, nearly all stormwater runoff quality monitoring is performed with automatic samplers in which the sampling intake is typically installed at the bottom of a storm sewer or channel. This method of sampling often results in a less accurate measurement of suspended sediment and associated pollutants due to the vertical variation in particle concentration caused by particle settling. In this study, the inaccuracies associated with sampling by conventional intakes for automatic samplers have been verified by testing with known suspended sediment concentrations and known particle sizes ranging from approximately 20 μm to 355 μm under various flow rates. Experimental results show that, for samples collected at a typical automatic sampler intake position, the ratio of sampled to feed suspended sediment concentration is up to 6600% without an intake strainer and up to 300% with a strainer. When the sampling intake is modified with multiple sampling tubes and fitted with a wing to provide lift (winged arm sampler intake), the accuracy of sampling improves substantially. With this modification, the differences between sampled and feed suspended sediment concentration were more consistent and the sampled to feed concentration ratio was accurate to within 10% for particle sizes up to 250 μm.

  9. An inversion of the estuarine circulation by sluice water discharge and its impact on suspended sediment transport

    NARCIS (Netherlands)

    Schulz, K.; Gerkema, T.


    The Wadden Sea is characterized by a complex topography of branching channels and intertidal flats, in which the interplay between fresh water discharges, wind forcing and the tidal current causes sediment transport rates and direction to be highly variable in space and time. During three field

  10. Chlor-alkali industrial contamination and riverine transport of mercury: Distribution and partitioning of mercury between water, suspended matter, and bottom sediment of the Thur River, France

    International Nuclear Information System (INIS)

    Hissler, Christophe; Probst, Jean-Luc


    Total dissolved and total particulate Hg mass balances were estimated during one hydrological period (July 2001-June 2002) in the Thur River basin, which is heavily polluted by chlor-alkali industrial activity. The seasonal variations of the Hg dynamics in the aquatic environment were assessed using total Hg concentrations in bottom sediment and suspended matter, and total and reactive dissolved Hg concentrations in the water. The impact of the chlor-alkali plant (CAP) remains the largest concern for Hg contamination of this river system. Upstream from the CAP, the Hg partitioning between dissolved and particulate phases was principally controlled by the dissolved fraction due to snow melting during spring high flow, while during low flow, Hg was primarily adsorbed onto particulates. Downstream from the CAP, the Hg partitioning is controlled by the concentration of dissolved organic and inorganic ligands and by the total suspended sediment (TSS) concentrations. Nevertheless, the particulate fluxes were five times higher than the dissolved ones. Most of the total annual flux of Hg supplied by the CAP to the river is transported to the outlet of the catchment (total Hg flux: 70 μg m -2 a -1 ). Downstream from the CAP, the bottom sediment, mainly composed of coarse sediment (>63 μm) and depleted in organic matter, has a weak capacity to trap Hg in the river channel and the stock of Hg is low (4 mg m -2 ) showing that the residence time of Hg in this river is short

  11. Continuous water-quality and suspended-sediment transport monitoring in the San Francisco Bay, California, water years 2011–13 (United States)

    Buchanan, Paul A.; Downing-Kunz, Maureen; Schoellhamer, David H.; Shellenbarger, Gregory; Weidich, Kurt


    The U.S. Geological Survey (USGS) monitors water quality and suspended-sediment transport in the San Francisco Bay. The San Francisco Bay area is home to millions of people, and the bay teems with both resident and migratory wildlife, plants, and fish. Fresh water mixes with salt water in the bay, which is subject both to riverine and marine (tides, waves, influx of salt water) influences. To understand this environment, the USGS, along with its partners, has been monitoring the bay’s waters continuously since 1988. Several water-quality variables are of particular importance to State and Federal resource managers and are monitored at key locations throughout the bay. Salinity, which indicates the relative mixing of fresh and ocean waters in the bay, is derived from specific conductance measurements. Water temperature, along with salinity, affects the density of water, which causes gravity driven circulation patterns and stratification in the water column. Turbidity is measured using light-scattering from suspended solids in water, and is used as a surrogate for suspended-sediment concentration (SSC). Suspended sediment often carries adsorbed contaminants; attenuates sunlight in the water column; deposits on tidal marsh and intertidal mudflats, which can help sustain these habitats as sea level rises; and deposits in ports and shipping channels, which can necessitate dredging. Dissolved oxygen, which is essential to a healthy ecosystem, is a fundamental indicator of water quality, and its concentration is affected by water temperature, salinity, ecosystem metabolism, tidal currents, and wind. Tidal currents in the bay reverse four times a day, and wind direction and intensity typically change on a daily cycle: consequently, salinity, water temperature, suspendedsediment concentration, and dissolvedoxygen concentration vary spatially and temporally throughout the bay, and continuous measurements are needed to observe these changes. The purpose of this fact sheet

  12. Studying Suspended Sediment Mechanism with Two-Phase PIV (United States)

    Matinpour, H.; Atkinson, J. F.; Bennett, S. J.; Guala, M.


    Suspended sediment transport affects soil erosion, agriculture and water resources quality. Turbulent diffusion is the most primary force to maintain sediments in suspension. Although extensive previous literature have been studying the interactions between turbulent motion and suspended sediment, mechanism of sediments in suspension is still poorly understood. In this study, we investigate suspension of sediments as two distinct phases: one phase of sediments and another phase of fluid with turbulent motions. We designed and deployed a state-of-the-art two-phase PIV measurement technique to discriminate these two phases and acquire velocities of each phase separately and simultaneously. The technique that we have developed is employing a computer-vision based method, which enables us to discriminate sediment particles from fluid tracer particles based on two thresholds, dissimilar particle sizes and different particle intensities. Results indicate that fluid turbulence decreases in the presence of suspended sediments. Obtaining only sediment phase consecutive images enable us to compute fluctuation sediment concentration. This result enlightens understanding of complex interaction between the fluctuation velocities and the fluctuation of associated mass and compares turbulent viscosity with turbulent eddy diffusivity experimentally.

  13. Temperature signal in suspended sediment export from an Alpine catchment

    Directory of Open Access Journals (Sweden)

    A. Costa


    Full Text Available Suspended sediment export from large Alpine catchments ( >  1000 km2 over decadal timescales is sensitive to a number of factors, including long-term variations in climate, the activation–deactivation of different sediment sources (proglacial areas, hillslopes, etc., transport through the fluvial system, and potential anthropogenic impacts on the sediment flux (e.g. through impoundments and flow regulation. Here, we report on a marked increase in suspended sediment concentrations observed near the outlet of the upper Rhône River Basin in the mid-1980s. This increase coincides with a statistically significant step-like increase in basin-wide mean air temperature. We explore the possible explanations of the suspended sediment rise in terms of changes in water discharge (transport capacity, and the activation of different potential sources of fine sediment (sediment supply in the catchment by hydroclimatic forcing. Time series of precipitation and temperature-driven snowmelt, snow cover, and ice melt simulated with a spatially distributed degree-day model, together with erosive rainfall on snow-free surfaces, are tested to explore possible reasons for the rise in suspended sediment concentration. We show that the abrupt change in air temperature reduced snow cover and the contribution of snowmelt, and enhanced ice melt. The results of statistical tests show that the onset of increased ice melt was likely to play a dominant role in the suspended sediment concentration rise in the mid-1980s. Temperature-driven enhanced melting of glaciers, which cover about 10 % of the catchment surface, can increase suspended sediment yields through an increased contribution of sediment-rich glacial meltwater, increased sediment availability due to glacier recession, and increased runoff from sediment-rich proglacial areas. The reduced extent and duration of snow cover in the catchment are also potential contributors to the rise in suspended sediment

  14. Continuous water-quality and suspended-sediment transport monitoring in the San Francisco Bay, California, water years 2014–15 (United States)

    Buchanan, Paul A.; Downing-Kunz, Maureen; Schoellhamer, David H.; Livsey, Daniel N.


    The U.S. Geological Survey (USGS) monitors water quality and suspended-sediment transport in the San Francisco Bay (bay) as part of a multi-agency effort to address management, water supply, and ecological concerns. The San Francisco Bay area is home to millions of people, and the bay teems both with resident and with migratory wildlife, plants, and fish. Freshwater mixes with salt water in the bay, which is subject both to riverine influences (floods, droughts, managed reservoir releases and freshwater diversions) and to marine influences (tides, waves, effects of salt water). To understand this environment, the USGS, along with its partners (see “Acknowledgements”), has been monitoring the bay’s waters continuously since 1988. Several water-quality variables are of particular importance to State and Federal resource managers and are monitored at key locations throughout the bay (fig. 1). Salinity, which indicates the relative mixing of fresh and ocean waters in the bay, is derived from specific conductance measurements. Water temperature, along with salinity, affects the density of water, which controls gravity-driven circulation patterns and stratification in the water column. Turbidity, a measure of light scattered from suspended particles in the water, is used to estimate suspended-sediment concentration (SSC). Suspended sediment affects the bay in multiple ways: attenuation of sunlight in the water column, affecting phytoplankton growth; deposition on tidal marsh and intertidal mudflats, which can help sustain these habitats as sea level rises; deposition in ports and shipping channels, which can necessitate dredging; and often, adsorption of contaminants, affecting their distribution and concentrations in the environment. Dissolved oxygen concentration, essential to a healthy ecosystem and a fundamental indicator of water quality, is affected by water temperature, salinity, ecosystem metabolism, tidal currents, and wind. Tidal currents in the bay

  15. Introduction to suspended-sediment sampling (United States)

    Nolan, K. Michael; Gray, John R.; Glysson, G. Douglas


    Knowledge of the amount and timing of sediment transport in streams is important to those directly or indirectly responsible for developing and managing water and land resources. Such data are often used to judge the health of watershed and the success or failure of activities designed to mitigate adverse impacts of sediment on streams and stream habitats. This training class presents an introduction to methods currently used by the U.S. Geological Survey (USGS) to sample suspended-sediment concentrations in streams. The presentation is narrated, but you control the pace of the presentation. If the computer you are using can view 'MPEG' videos you will be able to take advantage of videos interspersed in the presentation. A test, found at the end of the presentation, can be taken to assess how well you understood the training material. The class, which is registered as class SW4416 with the National Training Center of the USGS, should take two or three hours to complete. In order to use the presentation provided via this Web page, you will need to download a large disc images (linked below) and 'burn' it to a blank CD-ROM using a CD-ROM recorder on your computer. The presentation will only run on a Windows-based personal computer (PC). The presentation was developed using Macromedia Director MX 20041 and is contained in the file 'SIR05-5077.exe' which should autolaunch. If it does not, the presentation can be started by double-clicking on the file name. A sound card and speakers are necessary to take advantage of narrations that accompany the presentation. Text of narrations is provided, if you are unable to listen to narrations. Instructions for installing and running the presentation are included in the file 'Tutorial.htm', which is on the CD. 1 Registered Trademark: Macromedia Incorporated

  16. Sedimentation of suspended solids in ultrasound field

    Directory of Open Access Journals (Sweden)

    Vikulina Vera


    Full Text Available Physical and chemical effects of aquatic environment that occur in an ultrasonic field change the sedimentation rate of coagulated suspension. This might only happen in case of cavitation of ultrasonic filed that causes a change of potentials of the medium. Research of the influence of ultrasonic vibrations on coagulation of suspended solids within water purification allows expanding their scope of implementation. The objective of the research is to estimate the effect of ultrasound on the sedimentation of the suspended solids, to determine of the efficiency of the process in relation to the dose of the coagulant, and to calculate the numerical values of the constants in the theoretical equation. The experiment condition was held in the water with the clay substances before the introduction of the coagulant. The method of magnetostriction ultrasonic generator was applied to receive ultrasonic vibration. Estimate of concentration of clay particles in water was performed using photometry. As a result of the research, the obtained data allow determining the increase in efficiency of suspended particles sedimentation related to the dose of coagulant, depending on time of ultrasonic treatment. The experiments confirmed the connection between the effect of sedimentation in the coagulation process, the coagulant dose and the time of scoring. Studies have shown that the increase in the duration of ultrasonic treatment causes a decrease of administered doses of coagulant.

  17. Remote Sensing of Suspended Sediment Dynamics in the Mississippi Sound (United States)

    Merritt, D. N.; Skarke, A. D.; Silwal, S.; Dash, P.


    The Mississippi Sound is a semi-enclosed estuary between the coast of Mississippi and a chain of offshore barrier islands with relatively shallow water depths and high marine biodiversity that is wildly utilized for commercial fishing and public recreation. The discharge of sediment-laden rivers into the Mississippi Sound and the adjacent Northern Gulf of Mexico creates turbid plumes that can extend hundreds of square kilometers along the coast and persist for multiple days. The concentration of suspended sediment in these coastal waters is an important parameter in the calculation of regional sediment budgets as well as analysis of water-quality factors such as primary productivity, nutrient dynamics, and the transport of pollutants as well as pathogens. The spectral resolution, sampling frequency, and regional scale spatial domain associated with satellite based sensors makes remote sensing an ideal tool to monitor suspended sediment dynamics in the Northern Gulf of Mexico. Accordingly, the presented research evaluates the validity of published models that relate remote sensing reflectance with suspended sediment concentrations (SSC), for similar environmental settings, with 51 in situ observations of SSC from the Mississippi Sound. Additionally, regression analysis is used to correlate additional in situ observations of SSC in Mississippi Sound with coincident observations of visible and near-infrared band reflectance collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor aboard the Aqua satellite, in order to develop a site-specific empirical predictive model for SSC. Finally, specific parameters of the sampled suspended sediment such as grain size and mineralogy are analyzed in order to quantify their respective contributions to total remotely sensed reflectance.

  18. Acoustic measuring techniques for suspended sediment (United States)

    Gruber, P.; Felix, D.; Storti, G.; Lattuada, M.; Fleckenstein, P.; Deschwanden, F.


    Acoustic signals can be used in various ways for suspended sediment monitoring. One possibility which lends itself particularly well in the context of hydropower plants (HPPs), is to use installations for acoustic discharge measurement (ADM). Such installations already exist at waterways of many HPPs. Similar to certain turbidimeters, the attenuation of the forward scattered signal travelling through the water-sediment mixture is correlated with suspended sediment concentration (SSC). This correlation can be based on reference SSCs, e.g. from gravimetric analyses of bottle samples. Without the need of additional sensors and practically maintenance-free, this method is used successfully in the HPP Fieschertal to warn the HPP operator of high SSC to prevent excessive turbine abrasion. Acoustic methods and systems that allow for estimating both SSC and particle size distribution (PSD) are under development. The simultaneous determination of SSC and PSD is not possible using a single frequency. Therefore, multi-frequency approaches are investigated for generally scattered signals. When backscattered signals are used, a stronger frequency dependency can be exploited. However, the reliable simultaneous determination of particle size (and distribution) and concentration is still a major challenge due to a low signal-to-noise ratio and an ill- posed problem of estimating concentration and size from recorded signals. The optimal setup configuration (angles, frequencies) for such a system is not unique and further investigations are recommended.

  19. Residual fluxes of water, salt and suspended sediment in the Beypore Estuary

    Digital Repository Service at National Institute of Oceanography (India)

    AnilKumar, N.; Revichandran, C.; Sankaranarayanan, V.N.; Josanto, V.

    The monthly trends of the residual fluxes of salt and water and the transportation of suspended sediments in the Beypore estuarine system, Kerala, India were examined. At the river mouth the water flux was directed seaward during the postmonsoon...

  20. Near bed suspended sediment flux by single turbulent events (United States)

    Amirshahi, Seyed Mohammad; Kwoll, Eva; Winter, Christian


    The role of small scale single turbulent events in the vertical mixing of near bed suspended sediments was explored in a shallow shelf sea environment. High frequency velocity and suspended sediment concentration (SSC; calibrated from the backscatter intensity) were collected using an Acoustic Doppler Velocimeter (ADV). Using quadrant analysis, the despiked velocity time series was divided into turbulent events and small background fluctuations. Reynolds stress and Turbulent Kinetic Energy (TKE) calculated from all velocity samples, were compared to the same turbulent statistics calculated only from velocity samples classified as turbulent events (Reevents and TKEevents). The comparison showed that Reevents and TKEevents was increased 3 and 1.6 times, respectively, when small background fluctuations were removed and that the correlation with SSC for TKE could be improved through removal of the latter. The correlation between instantaneous vertical turbulent flux (w ‧) and SSC fluctuations (SSC ‧) exhibits a tidal pattern with the maximum correlation at peak ebb and flood currents, when strong turbulent events appear. Individual turbulent events were characterized by type, strength, duration and length. Cumulative vertical turbulent sediment fluxes and average SSC associated with individual turbulent events were calculated. Over the tidal cycle, ejections and sweeps were the most dominant events, transporting 50% and 36% of the cumulative vertical turbulent event sediment flux, respectively. Although the contribution of outward interactions to the vertical turbulent event sediment flux was low (11%), single outward interaction events were capable of inducing similar SSC ‧ as sweep events. The results suggest that on time scales of tens of minutes to hours, TKE may be appropriate to quantify turbulence in sediment transport studies, but that event characteristics, particular the upward turbulent flux need to be accounted for when considering sediment transport

  1. Trends in suspended-sediment loads and concentrations in the Mississippi River Basin, 1950–2009 (United States)

    Heimann, David C.; Sprague, Lori A.; Blevins, Dale W.


    Trends in loads and concentrations of suspended sediment and suspended sand generally were downward for stations within the Mississippi River Basin during the 60-, 34-, and 12-year periods analyzed. Sediment transport in the lower Mississippi River has historically been, and continues to be, most closely correlative to sediment contributions from the Missouri River, which generally carried the largest annual suspended-sediment load of the major Mississippi River subbasins. The closure of Fort Randall Dam in the upper Missouri River in 1952 was the single largest event in the recorded historical decline of suspended-sediment loads in the Mississippi River Basin. Impoundments on tributaries and sediment reductions as a result of implementation of agricultural conservation practices throughout the basin likely account for much of the remaining Mississippi River sediment transport decline. Scour of the main-stem channel downstream from the upper Missouri River impoundments is likely the largest source of suspended sand in the lower Missouri River. The Ohio River was second to the Missouri River in terms of sediment contributions, followed by the upper Mississippi and Arkansas Rivers. Declines in sediment loads and concentrations continued through the most recent analysis period (1998–2009) at available Mississippi River Basin stations. Analyses of flow-adjusted concentrations of suspended sediment indicate the recent downward temporal changes generally can be explained by corresponding decreases in streamflows.

  2. Transport of suspended particles in turbulent open channel flows

    NARCIS (Netherlands)

    Breugem, W.A.


    Two experiments are performed in order to investigate suspended sediment transport in a turbulent open channel flow. The first experiment used particle image velocimetry (PIV) to measure the fluid velocity with a high spatial resolution, while particle tracking velocimetry (PTV) was used to measure

  3. Suspended-Sediment Budget for the North Santiam River Basin, Oregon, Water Years 2005-08 (United States)

    Bragg, Heather M.; Uhrich, Mark A.


    Significant Findings An analysis of sediment transport in the North Santiam River basin during water years 2005-08 indicated that: Two-thirds of sediment input to Detroit Lake originated in the upper North Santiam River subbasin. Two-thirds of the sediment transported past Geren Island originated in the Little North Santiam River subbasin. The highest annual suspended-sediment load at any of the monitoring stations was the result of a debris flow on November 6, 2006, on Mount Jefferson. About 86 percent of the total sediment input to Detroit Lake was trapped in the lake, whereas 14 percent was transported farther downstream. More than 80 percent of the sediment transport in the basin was in November, December, and January. The variance in the annual suspended-sediment loads was better explained by the magnitude of the annual peak streamflow than by the annual mean streamflow.

  4. Concentrations and transport of suspended sediment, nutrients, and pesticides in the lower Mississippi-Atchafalaya River subbasin during the 2011 Mississippi River flood, April through July (United States)

    Welch, Heather L.; Coupe, Richard H.; Aulenbach, Brent T.


    High streamflow associated with the April–July 2011 Mississippi River flood forced the simultaneous opening of the three major flood-control structures in the lower Mississippi-Atchafalaya River subbasin for the first time in history in order to manage the amount of water moving through the system. The U.S. Geological Survey (USGS) collected samples for analysis of field properties, suspended-sediment concentration, particle-size, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, and up to 136 pesticides at 11 water-quality stations and 2 flood-control structures in the lower Mississippi-Atchafalaya River subbasin from just above the confluence of the upper Mississippi and Ohio Rivers downstream from April through July 2011. Monthly fluxes of suspended sediment, suspended sand, total nitrogen, nitrate plus nitrite, total phosphorus, orthophosphate, atrazine, simazine, metolachlor, and acetochlor were estimated at 9 stations and 2 flood-control structures during the flood period. Although concentrations during the 2011 flood were within the range of what has been observed historically, concentrations decreased during peak streamflow on the lower Mississippi River. Prior to the 2011 flood, high concentrations of suspended sediment and nitrate were observed in March 2011 at stations downstream of the confluence of the upper Mississippi and Ohio Rivers, which probably resulted in a loss of available material for movement during the flood. In addition, the major contributor of streamflow to the lower Mississippi-Atchafalaya River subbasin during April and May was the Ohio River, whose water contained lower concentrations of suspended sediment, pesticides, and nutrients than water from the upper Mississippi River. Estimated fluxes for the 4-month flood period were still quite high and contributed approximately 50 percent of the estimated annual suspended sediment, nitrate, and total phosphorus fluxes in 2011; the largest fluxes were estimated at

  5. Suspended sediment and sediment-associated contaminants in San Francisco Bay (United States)

    Schoellhamer, D.H.; Mumley, T.E.; Leatherbarrow, J.E.


    Water-quality managers desire information on the temporal and spatial variability of contaminant concentrations and the magnitudes of watershed and bed-sediment loads in San Francisco Bay. To help provide this information, the Regional Monitoring Program for Trace Substances in the San Francisco Estuary (RMP) takes advantage of the association of many contaminants with sediment particles by continuously measuring suspended-sediment concentration (SSC), which is an accurate, less costly, and more easily measured surrogate for several trace metals and organic contaminants. Continuous time series of SSC are collected at several sites in the Bay. Although semidiurnal and diurnal tidal fluctuations are present, most of the variability of SSC occurs at fortnightly, monthly, and semiannual tidal time scales. A seasonal cycle of sediment inflow, wind-wave resuspension, and winnowing of fine sediment also is observed. SSC and, thus, sediment-associated contaminants tend to be greater in shallower water, at the landward ends of the Bay, and in several localized estuarine turbidity maxima. Although understanding of sediment transport has improved in the first 10 years of the RMP, determining a simple mass budget of sediment or associated contaminants is confounded by uncertainties regarding sediment flux at boundaries, change in bed-sediment storage, and appropriate modeling techniques. Nevertheless, management of sediment-associated contaminants has improved greatly. Better understanding of sediment and sediment-associated contaminants in the Bay is of great interest to evaluate the value of control actions taken and the need for additional controls. ?? 2007 Elsevier Inc. All rights reserved.

  6. Turbulence Flow Characteristics of Suspended Sediments and its ...

    African Journals Online (AJOL)

    This paper presents an attempt to describe velocity distribution of suspended sediment laden flow by using a theory based on Monin-Obukhov Length L. It will be shown that experimental results from open channel flow with suspended sediments are better accounted for by this theory. The method involves the coupling of ...

  7. The particle size characteristics of fluvial suspended sediment in the Humber and Tweed catchments, UK (United States)

    Walling; Owens; Waterfall; Leeks; Wass


    This paper presents information on the absolute (chemically-dispersed) particle size characteristics of the suspended sediment transported by rivers in the Humber and Tweed basins during the period 1994-1998. For most of the rivers, > 95% of the suspended sediment load at the time of sampling was 63 microm (i.e. sand-sized material). The sediment transported in the two basins were similar. There were, however, noticeable spatial variations in the particle size composition of suspended sediment within the study basins, which reflected the particle size of the sediment sources and their spatial variation, and the selectivity of the sediment mobilization and delivery processes. When particle size parameters were plotted against discharge, there were no significant relationships, although there was some evidence of trends varying between sites. The lack of significant relationships with discharge reflects the fact that sediment particle size is largely supply-controlled, rather than a function of flow and hydraulics. When particle size variations were examined during individual storm events, there was evidence of a pulse of coarse sediment on the rising limb of the hydrograph. This may reflect the remobilization of coarse channel bed sediment as flow velocity and shear stress increase. Finer sediment was transported subsequently during the hydrograph peak and on the falling limb. The findings reported have important implications for understanding and modelling suspended sediment, and associated contaminant, dynamics in river basins.

  8. A Spatially Distributed Conceptual Model for Estimating Suspended Sediment Yield in Alpine catchments (United States)

    Costa, Anna; Molnar, Peter; Anghileri, Daniela


    Suspended sediment is associated with nutrient and contaminant transport in water courses. Estimating suspended sediment load is relevant for water-quality assessment, recreational activities, reservoir sedimentation issues, and ecological habitat assessment. Suspended sediment concentration (SSC) along channels is usually reproduced by suspended sediment rating curves, which relate SSC to discharge with a power law equation. Large uncertainty characterizes rating curves based only on discharge, because sediment supply is not explicitly accounted for. The aim of this work is to develop a source-oriented formulation of suspended sediment dynamics and to estimate suspended sediment yield at the outlet of a large Alpine catchment (upper Rhône basin, Switzerland). We propose a novel modelling approach for suspended sediment which accounts for sediment supply by taking into account the variety of sediment sources in an Alpine environment, i.e. the spatial location of sediment sources (e.g. distance from the outlet and lithology) and the different processes of sediment production and transport (e.g. by rainfall, overland flow, snowmelt). Four main sediment sources, typical of Alpine environments, are included in our model: glacial erosion, hillslope erosion, channel erosion and erosion by mass wasting processes. The predictive model is based on gridded datasets of precipitation and air temperature which drive spatially distributed degree-day models to simulate snowmelt and ice-melt, and determine erosive rainfall. A mass balance at the grid scale determines daily runoff. Each cell belongs to a different sediment source (e.g. hillslope, channel, glacier cell). The amount of sediment entrained and transported in suspension is simulated through non-linear functions of runoff, specific for sediment production and transport processes occurring at the grid scale (e.g. rainfall erosion, snowmelt-driven overland flow). Erodibility factors identify different lithological units

  9. Development of an Integrated Suspended Sediment Sampling System - Prototype Results (United States)

    Nerantzaki, Sofia; Moirogiorgou, Konstantia; Efstathiou, Dionissis; Giannakis, George; Voutsadaki, Stella; Zervakis, Michalis; Sibetheros, Ioannis A.; Zacharias, Ierotheos; Karatzas, George P.; Nikolaidis, Nikolaos P.


    The Mediterranean region is characterized by a unique micro-climate and a complex geologic and geomorphologic environment caused by its position in the Alpine orogenesis belt. Unique features of the region are the temporary rivers that are dry streams or streams with very low flow for most of the time over decadal time scales. One of their key characteristics is that they present flashy hydrographs with response times ranging from minutes to hours. It is crucial to monitor flash-flood events and observe their behavior since they can cause environmental degradation of the river's wider location area. The majority of sediment load is transferred during these flash events. Quantification of these fluxes through the development of new measuring devices is of outmost importance as it is the first step for a comprehensive understanding of the water quality, the soil erosion and erosion sources, and the sediment and nutrient transport routes. This work proposes an integrated suspended sediment sampling system which is implemented in a complex semi-arid Mediterranean watershed (i.e. the Koiliaris River Basin of Crete) with temporary flow tributaries and karstic springs. The system consists of sensors monitoring water stage and turbidity, an automated suspended sediment sampler, and an online camera recording video sequence of the river flow. Water stage and turbidity are continuously monitored and stage is converted to flow with the use of a rating curve; when either of these variables exceeds certain thresholds, the pump of the sediment sampler initiates sampling with a rotation proportional to the stage (flow weighted sampling). The water passes through a filter that captures the sediment, the solids are weighted after each storm and the data are converted to a total sediment flux. At the same time, the online camera derives optical measurements for the determination of the two-dimensional river flow velocity and the spatial sediment distribution by analyzing the Hue

  10. Suspended particles, colloids and radionuclide transport

    International Nuclear Information System (INIS)

    Chapman, N.; McKinley, I.; Shea, M.; Smellie, J.


    Radionuclide can be transported either in true solution or associated with suspended particles and colloids. The definitions of colloids and suspended particles are introduced and the mechanisms by which they can influence radionuclide transport discussed. The aim of the Pocos de Caldas investigations was to characterise the natural particulate material in the groundwater, to investigate the association of trace elements with this material and to obtain information on the stability and mobility of the particles. The concentration of suspended particles measured in the groundwater samples were low; the particles also appear to be immobile. (author) 4 figs

  11. The effects of Hurricane Hugo on suspended-sediment loads, Lago Loiza Basin, Puerto Rico (United States)

    Gellis, A.


    In the two main tributaries that enter Lago Loiza, Rio Grande de Loiza and Rio Gurabo, 99 600 tonnes of suspended sediment was transported by 58.2??106 m3 of runoff in a 48 h period. The storm-average suspended-sediment concentration in the Rio Grande de Loiza for Hurricane Hugo was 2290 mgl-1, the second lowest for the 12 storms that have been monitored at this site. In Rio Gurabo the storm-average suspended-sediment concentration was 1420 mg l -1, the sixth lowest recorded out of 15 monitored storms. In Quebrada Salvatierra, a small tributary to Rio Grande de Loiza, suspended-sediment concentrations were as low as 33 mg l-1 during peak runoff of 20m3s-1. Normally the suspended-sediment concentrations at this discharge are 300 mg l-1. Hurricane force winds seem to be the most important factor contributing to the lower than expected suspended-sediment loads. High winds caused vegetation and debris to be dislodged and displaced. Debris accumulated on hillslopes and in small channels, blocked bridges and formed debris dams. These dams caused local backwater effects that reduced stream velocities and decreased suspended-sediment loads. -from Author

  12. Sediment transport dynamics in the Central Himalaya: assessing during monsoon the erosion processes signature in the daily suspended load of the Narayani river (United States)

    Morin, Guillaume; Lavé, Jérôme; Lanord, Christian France; Prassad Gajurel, Ananta


    The evolution of mountainous landscapes is the result of competition between tectonic and erosional processes. In response to the creation of topography by tectonics, fluvial, glacial, and hillslope denudation processes erode topography, leading to rock exhumation and sediment redistribution. When trying to better document the links between climate, tectonic, or lithologic controls in mountain range evolution, a detailed understanding of the influence of each erosion process in a given environment is fundamental. At the scale of a whole mountain range, a systematic survey and monitoring of all the geomorphologic processes at work can rapidly become difficult. An alternative approach can be provided by studying the characteristics and temporal evolution of the sediments exported out of the range. In central Himalaya, the Narayani watershed presents contrasted lithologic, geochemical or isotopic signatures of the outcropping rocks as well as of the erosional processes: this particular setting allows conducting such type of approach by partly untangling the myopic vision of the spatial integration at the watershed scale. Based on the acquisition and analysis of a new dataset on the daily suspended load concentration and geochemical characteristics at the mountain outlet of one of the largest Himalayan rivers (drainage area = 30000 km2) bring several important results on Himalayan erosion, and on climatic and process controls. 1. Based on discrete depth sampling and on daily surface sampling of suspended load associated to flow characterization through ADCP measurements, we were first able to integrate sediment flux across a river cross-section and over time. We estimate for 2010 year an equivalent erosion rate of 1.8 +0.35/-0.2 mm/yr, and over the last 15 years, using past sediment load records from the DHM of Nepal, an equivalent erosion rate of 1.6 +0.3/-0.2 mm/yr. These rates are also in close agreement with the longer term ( 500 yrs) denudation rates of 1.7 mm

  13. Sources of suspended sediment in the Waikele watershed, Oʻahu, Hawaiʻi (United States)

    Izuka, Scot K.


    Data from streamflow/sediment gages and measurements of changes in channel-bed sediment storage were gathered between October 1, 2007, and September 30, 2010, to assess the sources of suspended sediment in the Waikele watershed, Oʻahu, Hawaiʻi. Streamflow from the watershed averaged 33 cubic feet per second during the study period, with interannual variations corresponding with variations in the frequency and magnitude of storm-flow peaks. Average streamflow during the study period was lower than the long-term average, but the study period included a storm on December 11, 2008, that caused record-high streamflows in parts of the watershed. Suspended-sediment yield from the Waikele watershed during the study period averaged 82,500 tons per year, which is 2.7 times higher than the long-term average. More than 90 percent of the yield during the study period was discharged during the December 11, 2008, storm. The study-period results are consistent with long-term records that show that the vast majority of suspended-sediment transport occurs during a few large storms. Results of this study also show that all but a small percentage of the suspended-sediment yield came from hillslopes. Only a small fraction of bed sediments is fine enough to be transported as suspended load; most bed sediments in the watershed are coarse. Silt and clay constitute less than 3 percent of the bed-sediment volume on average. Some larger clasts, however, can disintegrate during transport and contribute to the suspended load downstream. During the study period, suspended-sediment yield from the urbanized Mililani subbasin averaged 25 tons per year per square mile (tons/yr/mi2), which was much smaller than the yield from any other subbasin; these results indicate that urban land use yields much less sediment than other land uses. The wet, forested Kipapa subbasin had an average normalized hillslope suspended-sediment yield of 386 tons/yr/mi2; the average yield for forested areas in the

  14. Unravelling the relative contribution of bed and suspended sediment load on a large alluvial river (United States)

    Darby, S. E.; Hackney, C. R.; Parsons, D. R.; Leyland, J.; Aalto, R. E.; Nicholas, A. P.; Best, J.


    The world's largest rivers transport 19 billion tonnes of sediment to the coastal zone annually, often supporting large deltas that rely on this sediment load to maintain their elevation in the face of rising sea level, and to sustain high levels of agricultural productivity and biodiversity. However, the majority of estimates of sediment delivery to coastal regions pertain solely to the suspended fraction of the sediment load, with the bedload fraction often being neglected due to the difficulty in estimating bedload flux and the assumption that bedload contributes a minor (define suspended sediment rating curves using the inversion of acoustic return data from a series of acoustic Doppler current profiler surveys conducted through the Lower Mekong River in Cambodia, and into the bifurcating channels of the Mekong delta in Vietnam. Additionally, we detail estimates of bed-load sediment transport determined using repeat multibeam echo sounder surveys of the channel bed. By combining estimates of both fractions of the sediment load, we show the spatial and temporal contribution of bedload to the total sediment load of the Mekong and refine estimates of sediment transport to the Mekong delta. Our results indicate that the time-averaged suspended load transport rates for the Mekong River are 87 MT/yr, whilst bedload transport forms c. < 5% of the total sediment load within the Mekong River. Such estimates are integral to future channel management within this highly threatened river basin.

  15. Ensemble Modeling of Suspended Sediment in Steep Mountain Catchments (United States)

    Stewart, J.; Raseman, W. J.; Kasprzyk, J. R.; Livneh, B.


    Climatic and land cover changes present important uncertainties into the rates of soil erosion and sedimentation in watersheds. Soil erosion adds constituents to streams, altering water chemistry and streambed morphology, which can adversely affect aquatic life and poses a critical challenge for water treatment and reservoir management. The goal of this research is to establish estimates of sediment transport within large-scale mountainous catchments (>1000 km2). As sedimentation rates are impacted by numerous physical processes including soil, land cover, slope and climate; the results from seven models will be presented to quantify uncertainty and improve predictability. A broader inquiry made here is into the efficacy of model structure under different conditions. We present the results from empirical, stochastic, conceptual and physical models. These include empirical models: monovariate rating curve, multivariate regression and the Modified Universal Soil Loss Equation (MUSLE), to models with conceptual components: Soil Water Assessment Tool (SWAT) to more physically based models: Water Erosion Prediction Project (WEPP), Precipitation Runoff Modeling System (PRMS) and Distributed Hydrology Soil Vegetation Model (DHSVM). Key uncertainties will be characterized resulting from forcing inputs, parameter selection, scale discretization, and model structure. Calibration results from a multi-objective optimization routine will be presented that optimize parameters and identify performance trade-offs that will be used to develop uncertainty estimates in both streamflow and sediment projections. The outcomes of this research will highlight critical issues relevant to large-scale hydrologic and suspended sediment prediction initiatives.

  16. Substantial export of suspended sediment to the global oceans from glacial erosion in Greenland (United States)

    Overeem, I.; Hudson, B. D.; Syvitski, J. P. M.; Mikkelsen, A. B.; Hasholt, B.; van den Broeke, M. R.; Noël, B. P. Y.; Morlighem, M.


    Limited measurements along Greenland's remote coastline hamper quantification of the sediment and associated nutrients draining the Greenland ice sheet, despite the potential influence of river-transported suspended sediment on phytoplankton blooms and carbon sequestration. Here we calibrate satellite imagery to estimate suspended sediment concentration for 160 proglacial rivers across Greenland. Combining these suspended sediment reconstructions with numerical calculations of meltwater runoff, we quantify the amount and spatial pattern of sediment export from the ice sheet. We find that, although runoff from Greenland represents only 1.1% of the Earth's freshwater flux, the Greenland ice sheet produces approximately 8% of the modern fluvial export of suspended sediment to the global ocean. Sediment loads are highly variable between rivers, consistent with observed differences in ice dynamics and thus with control by glacial erosion. Rivers that originate from deeply incised, fast-moving glacial tongues form distinct sediment-export hotspots: just 15% of Greenland's rivers transport 80% of the total sediment load of the ice sheet. We conclude that future acceleration of melt and ice sheet flow may increase sediment delivery from Greenland to its fjords and the nearby ocean.

  17. Suspended sediment apportionment in a South-Korean mountain catchment (United States)

    Birkholz, Axel; Meusburger, Katrin; Park, Ji-Hyung; Alewell, Christine


    Due to the rapid agricultural expansion and intensification during the last decades in South-Korea, large areas of hill slope forests were transformed to paddies and vegetable fields. The intensive agriculture and the easily erodible soils in our catchment are a major reason for the increased erosion causing suspended sediments to infiltrate into the close drinking water reservoir. The drinking water reservoir Lake Soyang provides water supply for over ten million people in Seoul. Landscape managers need to know the exact origin of these sediments before they can create landscape amelioration schemes. We applied a compound-specific stable isotope (CSSI) approach (Alewell et al., 2015) to apportion the sources of the suspended sediments between forest and agricultural soil contribution to the suspended sediments in a different catchment and applied the same approach to identify and quantify the different sources of the suspended sediments in the river(s) contributing to Lake Soyang. We sampled eight soil sites within the catchment considering the different landuse types forest, rice paddies, maize and vegetables. Suspended sediments were sampled at three outlets of the different sub-catchments. Soils and suspended sediments are analysed for bulk carbon and nitrogen isotopes, compound-specific carbon isotopes of plant-wax derived long-chain fatty acids and long-chain n-alkanes. Fatty acid and alkane isotopes are then used in mixing calculations and the mixing model software IsoSource to find out the contribution of the different source soils to the suspended sediments. We present first data of the source soils and the suspended sediments. C. Alewell, A. Birkholz, K. Meusburger, Y. Schindler-Wildhaber, L. Mabit, 2015. Sediment source attribution from multiple land use systems with CSIA. Biogeosciences Discuss. 12: 14245-14269.

  18. A suspended sediment yield predictive equation for river basins in ...

    African Journals Online (AJOL)

    The fit was found to be better than those relating mean annual specific suspended sediment yield to basin area or runoff only. Since many stream gauging stations in the country have no records on fluvial sediment, the empirical equation can be used to obtain preliminary estimates of expected sediment load of streams for ...

  19. Sediment transport in an active erodible channel bend of ...

    Indian Academy of Sciences (India)

    Vertical distribution of suspended sediment concentration follows a power function with normalized depth. Average bed-material concentration at the reach level is computed from observed sediment profiles, and is compared against various sediment transport functions. Results show that the sediment transport function ...

  20. Estimation of suspended sediment concentration in rivers using acoustic methods. (United States)

    Elçi, Sebnem; Aydin, Ramazan; Work, Paul A


    Acoustic Doppler current meters (ADV, ADCP, and ADP) are widely used in water systems to measure flow velocities and velocity profiles. Although these meters are designed for flow velocity measurements, they can also provide information defining the quantity of particulate matter in the water, after appropriate calibration. When an acoustic instrument is calibrated for a water system, no additional sensor is needed to measure suspended sediment concentration (SSC). This provides the simultaneous measurements of velocity and concentration required for most sediment transport studies. The performance of acoustic Doppler current meters for measuring SSC was investigated in different studies where signal-to-noise ratio (SNR) and suspended sediment concentration were related using different formulations. However, these studies were each limited to a single study site where neither the effect of particle size nor the effect of temperature was investigated. In this study, different parameters that affect the performance of an ADV for the prediction of SSC are investigated. In order to investigate the reliability of an ADV for SSC measurements in different environments, flow and SSC measurements were made in different streams located in the Aegean region of Turkey having different soil types. Soil samples were collected from all measuring stations and particle size analysis was conducted by mechanical means. Multivariate analysis was utilized to investigate the effect of soil type and water temperature on the measurements. Statistical analysis indicates that SNR readings ob tained from the ADV are affected by water temperature and particle size distribution of the soil, as expected, and a prediction model is presented relating SNR readings to SSC mea surements where both water temperature and sediment characteristics type are incorporated into the model. The coefficients of the suggested model were obtained using the multivariate anal ysis. Effect of high turbidity

  1. Environmental controls, sediment sources and spatiotemporal variability of suspended sediment yields in partly glacierized catchment systems in western Norway (United States)

    Beylich, Achim A.; Laute, Katja; Storms, Joep E. A.


    This work focuses on environmental controls, sediment sources and the spatiotemporal variability of suspended sediment yields in the neighboring, partly glacierized and steep Erdalen (79.5 km2) and Bødalen (60.1 km2) catchment systems in the fjord landscape of the inner Nordfjord in western Norway. Field work, including extended samplings and measurements, was carried out since 2004 in Erdalen and since 2008 in Bødalen. Fluvial suspended sediment transport in the inner Nordfjord is altogether supply-limited and larger thermally and/or pluvially generated runoff events occurring mostly during the period April-November are needed to mobilize and transport significant amounts of suspended sediments. The distinct intra- and inter-annual temporal variability of suspended sediment transport found is mostly controlled by meteorological events, with most suspended sediment transport occurring during pluvial events in autumn (September-November), followed by mostly thermally determined glacier melt in summer (July-August), and by mostly thermally determined snowmelt in spring (April-June). Extreme rainfall events (>70 mm/d) in autumn can trigger relevant debris-flow activity that can cause significant transfers of suspended sediments from ice-free surface areas with sedimentary covers into main stream channels and is particularly important for fluvial suspended sediment transport. In years with occurring relevant debris-flow activity the total annual drainage-basin wide suspended sediment yields are strongly determined by these single extreme events. The share of glacier coverage, followed by steepness of slopes, and degree of vegetation cover in ice-free surface areas with sedimentary covers are the main controls of the detected spatial variability of suspended sediment yields. The contemporary sediment delivery from glacierized surface areas through different outlet glaciers shows a high spatial variability which is mostly explained by a spatially variable availability

  2. Attribution of climate change, vegetation restoration, and engineering measures to the reduction of suspended sediment in the Kejie catchment, southwest China

    NARCIS (Netherlands)

    Ma, X.; Lu, X.; Noordwijk, van M.; Li, J.T.; Xu, J.C.


    Suspended sediment transport in rivers is controlled by terrain, climate, and human activities. These variables affect hillslope and riverbank erosion at the source, transport velocities and sedimentation opportunities in the river channel, and trapping in reservoirs. The relative importance of

  3. Sources of suspended-sediment flux in streams of the chesapeake bay watershed: A regional application of the sparrow model (United States)

    Brakebill, J.W.; Ator, S.W.; Schwarz, G.E.


    We describe the sources and transport of fluvial suspended sediment in nontidal streams of the Chesapeake Bay watershed and vicinity. We applied SPAtially Referenced Regressions on Watershed attributes, which spatially correlates estimated mean annual flux of suspended sediment in nontidal streams with sources of suspended sediment and transport factors. According to our model, urban development generates on average the greatest amount of suspended sediment per unit area (3,928 Mg/km2/year), although agriculture is much more widespread and is the greatest overall source of suspended sediment (57 Mg/km2/year). Factors affecting sediment transport from uplands to streams include mean basin slope, reservoirs, physiography, and soil permeability. On average, 59% of upland suspended sediment generated is temporarily stored along large rivers draining the Coastal Plain or in reservoirs throughout the watershed. Applying erosion and sediment controls from agriculture and urban development in areas of the northern Piedmont close to the upper Bay, where the combined effects of watershed characteristics on sediment transport have the greatest influence may be most helpful in mitigating sedimentation in the bay and its tributaries. Stream restoration efforts addressing floodplain and bank stabilization and incision may be more effective in smaller, headwater streams outside of the Coastal Plain. ?? 2010 American Water Resources Association. No claim to original U.S. government works.

  4. Flow fields, bed shear stresses, and suspended bed sediment dynamics in bifurcations of a large river (United States)

    Szupiany, R. N.; Amsler, M. L.; Hernandez, J.; Parsons, D. R.; Best, J. L.; Fornari, E.; Trento, A.


    Channel bifurcations associated with bars and islands are important nodes in braided rivers and may control flow partitioning and thus affect downstream confluences, as well as the formation and dynamics of bars. However, the morphodynamic processes associated with bar formation are poorly understood, and previous studies have largely concerned laboratory experiments, small natural streams, or numerical analyses with large Froude numbers, high slopes, and low Shields stresses. In these cases, the morphologic changes at bifurcations are relatively rapid, with predominant bed load transport and the suspended load playing a minor role. In this paper, the evolution of the flow structure and suspended bed sediment transport along four expansion-diffluence units in the Rio Paraná, Argentina, are described. The Rio Paraná is a large multichannel river with a bed composed of medium and fine sands and possesses low Froude numbers and high suspended bed material transport. Primary and secondary flow velocity components were measured with an acoustic Doppler current profiler (ADCP) along the expansion-diffluence units, and the backscatter signal of the ADCP was calibrated to allow simultaneous measurements of suspended bed sediment concentrations. The interactions between these variables show that the cores of primary flow velocity and suspended bed sediment concentration do not necessarily follow the thalweg at the bifurcation and that inertial effects on the suspended bed sediment may influence the morphodynamics of bar formation. It is suggested that changes in flow stage, as well as the presence of vegetation, may further increase the deposition of suspended bed sediment at the bar head. This study suggests that the ratio of suspended bed material to bed load is an important factor controlling the morphodynamics of bifurcations in large sand bed braided rivers.

  5. Quantifying suspended sediment loads delivered to Cheney Reservoir, Kansas: Temporal patterns and management implications (United States)

    Stone, Mandy L.; Juracek, Kyle E.; Graham, Jennifer L.; Foster, Guy


    Cheney Reservoir, constructed during 1962 to 1965, is the primary water supply for the city of Wichita, the largest city in Kansas. Sediment is an important concern for the reservoir as it degrades water quality and progressively decreases water storage capacity. Long-term data collection provided a unique opportunity to estimate the annual suspended sediment loads for the entire history of the reservoir. To quantify and characterize sediment loading to Cheney Reservoir, discrete suspended sediment samples and continuously measured streamflow data were collected from the North Fork Ninnescah River, the primary inflow to Cheney Reservoir, over a 48-year period. Continuous turbidity data also were collected over a 15-year period. These data were used together to develop simple linear regression models to compute continuous suspended sediment concentrations and loads from 1966 to 2013. The inclusion of turbidity as an additional explanatory variable with streamflow improved regression model diagnostics and increased the amount of variability in suspended sediment concentration explained by 14%. Using suspended sediment concentration from the streamflow-only model, the average annual suspended sediment load was 102,517 t (113,006 tn) and ranged from 4,826 t (5,320 tn) in 1966 to 967,569 t (1,066,562 tn) in 1979. The sediment load in 1979 accounted for about 20% of the total load over the 48-year history of the reservoir and 92% of the 1979 sediment load occurred in one 24-hour period during a 1% annual exceedance probability flow event (104-year flood). Nearly 60% of the reservoir sediment load during the 48-year study period occurred in 5 years with extreme flow events (9% to 1% annual exceedance probability, or 11- to 104-year flood events). A substantial portion (41%) of sediment was transported to the reservoir during five storm events spanning only eight 24-hour periods during 1966 to 2013. Annual suspended sediment load estimates based on streamflow were, on

  6. Numerical modelling of hydro-morphological processes dominated by fine suspended sediment in a stormwater pond (United States)

    Guan, Mingfu; Ahilan, Sangaralingam; Yu, Dapeng; Peng, Yong; Wright, Nigel


    Fine sediment plays crucial and multiple roles in the hydrological, ecological and geomorphological functioning of river systems. This study employs a two-dimensional (2D) numerical model to track the hydro-morphological processes dominated by fine suspended sediment, including the prediction of sediment concentration in flow bodies, and erosion and deposition caused by sediment transport. The model is governed by 2D full shallow water equations with which an advection-diffusion equation for fine sediment is coupled. Bed erosion and sedimentation are updated by a bed deformation model based on local sediment entrainment and settling flux in flow bodies. The model is initially validated with the three laboratory-scale experimental events where suspended load plays a dominant role. Satisfactory simulation results confirm the model's capability in capturing hydro-morphodynamic processes dominated by fine suspended sediment at laboratory-scale. Applications to sedimentation in a stormwater pond are conducted to develop the process-based understanding of fine sediment dynamics over a variety of flow conditions. Urban flows with 5-year, 30-year and 100-year return period and the extreme flood event in 2012 are simulated. The modelled results deliver a step change in understanding fine sediment dynamics in stormwater ponds. The model is capable of quantitatively simulating and qualitatively assessing the performance of a stormwater pond in managing urban water quantity and quality.

  7. Estimation of suspended sediment concentration by acoustic ...

    African Journals Online (AJOL)

    concentration of sediments such as glass spheres or sand. However, the acoustic properties of natural sediments vary and depend on many parameters such as particle size, shape, mineralogy and distribution of those parameters in sample. Therefore, this study was conducted to determine the possibility of soil sediment ...

  8. Sediment Characteristics of Tennessee Streams and Reservoirs

    National Research Council Canada - National Science Library

    Trimble, Stanley W; Carey, William P


    Suspended-sediment and reservoir sedimentation data have been analyzed to determine sediment yields and transport characteristics of Tennessee streams Data from 31 reservoirs plus suspended-sediment...

  9. Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations (United States)

    Voichick, Nicholas; Topping, David J.; Griffiths, Ronald E.


    Turbidity, a measure of water clarity, is monitored for a variety of purposes including (1) to help determine whether water is safe to drink, (2) to establish background conditions of lakes and rivers and detect pollution caused by construction projects and stormwater discharge, (3) to study sediment transport in rivers and erosion in catchments, (4) to manage siltation of water reservoirs, and (5) to establish connections with aquatic biological properties, such as primary production and predator-prey interactions. Turbidity is typically measured with an optical probe that detects light scattered from particles in the water. Probes have defined upper limits of the range of turbidity that they can measure. The general assumption is that when turbidity exceeds this upper limit, the values of turbidity will be constant, i.e., the probe is pegged; however, this assumption is not necessarily valid. In rivers with limited variation in the physical properties of the suspended sediment, at lower suspended-sediment concentrations, an increase in suspended-sediment concentration will cause a linear increase in turbidity. When the suspended-sediment concentration in these rivers is high, turbidity levels can exceed the upper measurement limit of an optical probe and record a constant pegged value. However, at extremely high suspended-sediment concentrations, optical turbidity probes do not necessarily stay pegged at a constant value. Data from the Colorado River in Grand Canyon, Arizona, USA, and a laboratory experiment both demonstrate that when turbidity exceeds instrument-pegged conditions, increasing suspended-sediment concentration (and thus increasing turbidity) may cause optical probes to record decreasing false turbidity values that appear to be within the valid measurement range of the probe. Therefore, under high-turbidity conditions, other surrogate measurements of turbidity (e.g., acoustic-attenuation measurements or suspended-sediment samples) are necessary to

  10. Bankfull discharge and sediment transport in northwestern California (United States)

    K. M. Nolan; T. E. Lisle; H. M. Kelsey


    Abstract - High-magnitude, low-frequency discharges are more responsible for transporting suspended sediment and forming channels in northwestern California than in previously studied areas. Bankfull discharge and the magnitude and frequency of suspended sediment discharge were determined at five gaging stations in northwestern California. Although discharges below...

  11. Estimated Loads of Suspended Sediment and Selected Trace Elements Transported through the Milltown Reservoir Project Area Before and After the Breaching of Milltown Dam in the Upper Clark Fork Basin, Montana, Water Year 2008 (United States)

    Lambing, John H.; Sando, Steven K.


    This report presents estimated daily and cumulative loads of suspended sediment and selected trace elements transported during water year 2008 at three streamflow-gaging stations that bracket the Milltown Reservoir project area in the upper Clark Fork basin of western Montana. Milltown Reservoir is a National Priorities List Superfund site where sediments enriched in trace elements from historical mining and ore processing have been deposited since the construction of Milltown Dam in 1907. Milltown Dam was breached on March 28, 2008, as part of Superfund remedial activities to remove the dam and contaminated sediment that had accumulated in Milltown Reservoir. The estimated loads transported through the project area during the periods before and after the breaching of Milltown Dam, and for the entire water year 2008, were used to quantify the net gain or loss (mass balance) of suspended sediment and trace elements within the project area during the transition from a reservoir environment to a free-flowing river. This study was done in cooperation with the U.S. Environmental Protection Agency. Streamflow during water year 2008 compared to long-term streamflow, as represented by the record for Clark Fork above Missoula (water years 1930-2008), generally was below normal (long-term median) from about October 2007 through April 2008. Sustained runoff started in mid-April, which increased flows to near normal by mid-May. After mid-May, flows sharply increased to above normal, reaching a maximum daily mean streamflow of 16,800 cubic feet per second (ft3/s) on May 21, which essentially equaled the long-term 10th-exceedance percentile for that date. Flows substantially above normal were sustained through June, then decreased through the summer and reached near-normal by August. Annual mean streamflow during water year 2008 (3,040 ft3/s) was 105 percent of the long-term mean annual streamflow (2,900 ft3/s). The annual peak flow (17,500 ft3/s) occurred on May 21 and was 112

  12. Optimal estimation of suspended-sediment concentrations in streams (United States)

    Holtschlag, D.J.


    Optimal estimators are developed for computation of suspended-sediment concentrations in streams. The estimators are a function of parameters, computed by use of generalized least squares, which simultaneously account for effects of streamflow, seasonal variations in average sediment concentrations, a dynamic error component, and the uncertainty in concentration measurements. The parameters are used in a Kalman filter for on-line estimation and an associated smoother for off-line estimation of suspended-sediment concentrations. The accuracies of the optimal estimators are compared with alternative time-averaging interpolators and flow-weighting regression estimators by use of long-term daily-mean suspended-sediment concentration and streamflow data from 10 sites within the United States. For sampling intervals from 3 to 48 days, the standard errors of on-line and off-line optimal estimators ranged from 52.7 to 107%, and from 39.5 to 93.0%, respectively. The corresponding standard errors of linear and cubic-spline interpolators ranged from 48.8 to 158%, and from 50.6 to 176%, respectively. The standard errors of simple and multiple regression estimators, which did not vary with the sampling interval, were 124 and 105%, respectively. Thus, the optimal off-line estimator (Kalman smoother) had the lowest error characteristics of those evaluated. Because suspended-sediment concentrations are typically measured at less than 3-day intervals, use of optimal estimators will likely result in significant improvements in the accuracy of continuous suspended-sediment concentration records. Additional research on the integration of direct suspended-sediment concentration measurements and optimal estimators applied at hourly or shorter intervals is needed.

  13. Suspended sediment concentration and particle size distribution ...

    Indian Academy of Sciences (India)

    K, Fukushima T, Mizugaki S and Onda Y 2008 Devel- opment, evaluation and interpretation of sediment rat- ing curves for a Japanese small mountainous reforested watershed; Geoderma 144 198–211. Sadeghi S H R and Saeidi P 2010 Reliability of sediment rating curves for a deciduous forest watershed in Iran; J. Hydrol ...

  14. Suspended sediment diffusion mechanisms in the Yangtze Estuary influenced by wind fields (United States)

    Wang, Lihua; Zhou, Yunxuan; Shen, Fang


    The complexity of suspended sediment concentration (SSC) distribution and diffusion has been widely recognized because it is influenced by sediment supply and various hydrodynamic forcing conditions that vary over space and over time. Sediment suspended by waves and transported by currents are the dominant sediment transport mechanisms in estuarine and coastal areas. However, it is unclear to what extent the SSC distribution is impacted by each hydrodynamic factor. Research on the quantitative influence of wind fields on the SSC diffusion range will contribute to a better understanding of the characteristics of sediment transport change and sedimentary geomorphic evolution. This study determined SSC from three Envisat Medium-Resolution Imaging Spectrometer acquisitions, covering the Yangtze Estuary and adjacent water area under the same season and tidal conditions but with varying wind conditions. SSC was examined based on the Semi-Empirical Radiative Transfer model, which has been well validated with the observation data. Integrating the corresponding wind field information from European Centre for Medium-Range Weather Forecasts further facilitated the discussion of wind fields affecting SSC, and in turn the influence of water and suspended sediment transportation and diffusion in the Yangtze estuarine and coastal area. The results demonstrated that the SSC present much more distinctive fluvial features in the inner estuary and wind fields are one of the major factors controlling the range of turbid water diffusion.

  15. The Scientific and Societal Need for Accurate Global Remote Sensing of Marine Suspended Sediments (United States)

    Acker, James G.


    Population pressure, commercial development, and climate change are expected to cause continuing alteration of the vital oceanic coastal zone environment. These pressures will influence both the geology and biology of the littoral, nearshore, and continental shelf regions. A pressing need for global observation of coastal change processes is an accurate remotely-sensed data product for marine suspended sediments. The concentration, delivery, transport, and deposition of sediments is strongly relevant to coastal primary production, inland and coastal hydrology, coastal erosion, and loss of fragile wetland and island habitats. Sediment transport and deposition is also related to anthropogenic activities including agriculture, fisheries, aquaculture, harbor and port commerce, and military operations. Because accurate estimation of marine suspended sediment concentrations requires advanced ocean optical analysis, a focused collaborative program of algorithm development and assessment is recommended, following the successful experience of data refinement for remotely-sensed global ocean chlorophyll concentrations.

  16. Modeling suspended sediment discharge from the Waipaoa River system, New Zealand : The last 3000 years

    NARCIS (Netherlands)

    Kettner, A.J.; Gomez, B.; Syvitski, J.P.M.


    HydroTrend, a hydrologic-transport model, is used to simulate the water and suspended sediment discharge of the Waipaoa River system over the last 3 Kyr, a time period in which a well-documented sequence of natural events and anthropogenic activities that profoundly impacted drainage basin processes

  17. [Distributions of phosphorus fractions in suspended sediments and surface sediments of Tiaoxi mainstreams and cause analysis]. (United States)

    Chen, Hai-Long; Yuan, Xu-Yin; Wang, Huan; Li, Zheng-Yang; Xu, Hai-Yan


    Phosphorus is a primary nutrient showing the water quality status of river and inducing eutrophication, and a different phosphorus fraction can make diverse contributions to water quality. Four phosphorus forms of suspended sediments and surface sediments in Tiaoxi mainstreams were measured using a sequential extraction procedure, and the distributions of their forms were discussed. The results showed that the tropic status of Xitiaoxi River was inferior to that of Dongtiaoxi River as a whole, and the water quality in the middle reach of Dongtiaoxi River was better than that in the upper and lower reaches. The contents of nutrient elements in suspended sediments were significantly higher than those in surface sediment, which indicated an enrichment of nutrient in fine sediment. The percentages of the loosely absorbed phosphorus ( NH4Cl-P), the reductant phosphorus (BD-P) and the metal oxide bound phosphorus (NaOH-P) in the suspended sediment were higher than those in surface sediment, while the percentage of the calcium bound phosphorus (HCl-P) showed a reverse trend. Correlation analyses between phosphorus forms and chemical compositions of suspended sediments and surface sediments were performed. The results showed the phosphorus forms in suspended sediments and surface sediments of Xitiaoxi River had weak relationships with mineral components, while those in the Dongtiaoxi River had strong relationships with mineral, especially OM and clay mineral. The cause was associated with the geological setting and material sources in Tiaoxi watershed.

  18. A spatially explicit suspended-sediment load model for western Oregon (United States)

    Wise, Daniel R.; O'Connor, Jim


    We calibrated the watershed model SPARROW (Spatially Referenced Regressions on Watershed attributes) to give estimates of suspended-sediment loads for western Oregon and parts of northwestern California. Estimates of suspended-sediment loads were derived from a nonlinear least squares regression that related explanatory variables representing landscape and transport conditions to measured suspended-sediment loads at 68 measurement stations. The model gives estimates of model coefficients and their uncertainty within a spatial framework defined by the National Hydrography Dataset Plus hydrologic network. The resulting model explained 64 percent of the variability in suspended-sediment yield and had a root mean squared error value of 0.737. The predictor variables selected for the final model were (1) generalized lithologic province, (2) mean annual precipitation, and (3) burned area (by recent wildfire). Other landscape characteristics also were considered, but they were not significant predictors of sediment transport, were strongly correlated with another predictor variable, or were not as significant as the predictors selected for the final model.

  19. Modelling of sediment transport at Muria peninsula coastal, Jepara

    International Nuclear Information System (INIS)

    Heni Susiati; Yarianto SBS; Wahyu Pandoe; Eko Kusratmoko; Aris Poniman


    Modelling of transport sediment modelling at Muria Peninsula have been done. In this study we had been used mathematical model that consist of hydrodynamics and sediment transport . Data input for modelling has been used tidal, monsoon wind, and river debit. Simulation result of sediment transport modelling showed that tides pattern and seasonal variations are the main causes of variations in the suspended sediment distribution in Muria Peninsula. (author)

  20. Element Geochemical Analysis of the Contribution of Aeolian Sand to Suspended Sediment in Desert Stream Flash Floods

    Directory of Open Access Journals (Sweden)

    Xiaopeng Jia


    Full Text Available The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.

  1. Element geochemical analysis of the contribution of aeolian sand to suspended sediment in desert stream flash floods. (United States)

    Jia, Xiaopeng; Wang, Haibing


    The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.

  2. Oscillatory infragravity wave contribution to surf zone sediment transport

    DEFF Research Database (Denmark)

    Aagaard, Troels; Greenwood, Brian


    Field measurements reported in the literature demonstrate that suspended sediment transport due to infragravity wave motions can sometimes be very large and dominate the net sediment transport at a given measurement location within the surf zone. At other times, however, this transport component...

  3. Modelling of Suspended Sediment Discharge for Masinga ...

    African Journals Online (AJOL)

    Masinga reservoir is experiencing high rates of siltation due to accelerated soil erosion in the catchment occasioned by rapid deforestation. There is ... basins at the two mouths of the reservoir and flushing out sediments through bottom outlet gates are suggested to provide solution to Masinga's myriad siltation problems.

  4. Quantifying ratios of suspended sediment sources in forested headwater streams following timber-harvesting operations (United States)

    Rachels, A. A.; Bladon, K. D.; Bywater-Reyes, S.


    Historically, timber-harvesting has increased fine sediment inputs to streams due to increased hillslope and streambank erosion and mass wasting along roads. However, under modern best management practices, the relative importance and variability of these sources is poorly understood. We present preliminary results from an ongoing study investigating the primary sources of suspended sediment in Oregon Coast Range streams influenced by timber harvesting. We instrumented two catchments, Enos Creek (harvested 2016) and Scheele Creek (reference) in fall 2016. Phillips samplers (5-6 per catchment) have been deployed longitudinally down the streams to enable robust characterization of suspended sediments—the collected samples integrate the chemical signatures of upstream sediment exports. We will collect samples monthly over 2 wet seasons and return to the laboratory to analyze the sediment using source fingerprinting approaches. The fingerprinting technique compares the chemical properties of stream sediment samples with the chemical properties of potential source areas, including 1) roads, 2) stream banks, and 3) hillslopes. To design a robust model for sediment-source identification, different types of chemical data are required—we will analyze sediment samples using a combination of: a) stable isotopes and C/N ratios (i.e., δ15N, δ13C, and C/N), b) geochemistry (Fe, K, and Ca), and c) radiogenic isotopes (137Cs and 210Pb). At the harvested site, the C/N ratios of the streambanks (17.9 ± 3.8) and the hillslopes (26.4 ± 4.8) are significantly different from one another (p = .016). C/N ratios of the suspended sediment (20.5 ± 2.0) are intermediate values between potential endmembers and behave conservatively with transport. The C/N ratios of the suspended sediment appear unaffected by roads (18.9 ± 8.7) along specific sections of the stream, suggesting that roads are not a primary sediment contributor. Under this assumption, the suspended sediment is, on

  5. Heavy metal ions adsorption by suspended particle and sediment of ...

    African Journals Online (AJOL)



    Jan 10, 2012 ... 7000, and 11000 mg/l, increased the samples of river water; and then they are mixed in JAR TEST apparatus twice for one and ... Key words: Chalus River, adsorption, heavy metal, suspended particle, sediment. INTRODUCTION .... concentrations using the conventional method of flame atomic absorption ...

  6. Reduction in density of suspended - sediment - laden natural waters

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A; Desa, E.; Desa, E.; Smith, D.; Peshwe, V.B.; VijayKumar, K.; Desa, J.A

    to 0.4% - 4.5%) that of the density of the same water without suspended sediment. Teh values of peff in a given site differed from one tidal cycle to another (approx equal to 1.9%). These values varied slightly (less than 0.8%) from mid-tide to slack...

  7. Estimated loads of suspended sediment and selected trace elements transported through the Clark Fork basin, Montana, in selected periods before and after the breach of Milltown Dam (water years 1985-2009) (United States)

    Sando, Steven K.; Lambing, John H.


    Milltown Reservoir is a National Priorities List Superfund site in the upper Clark Fork basin of western Montana where sediments enriched in trace elements from historical mining and ore processing have been deposited since the completion of Milltown Dam in 1908. Milltown Dam was breached on March 28, 2008, as part of Superfund remediation activities to remove the dam and excavate contaminated sediment that had accumulated in Milltown Reservoir. In preparation for the breach of Milltown Dam, permanent drawdown of Milltown Reservoir began on June 1, 2006, and lowered the water-surface elevation by about 10 to 12 feet. After the breach of Milltown Dam, the water-surface elevation was lowered an additional 17 feet. Hydrologic data-collection activities were conducted by the U.S. Geological Survey in cooperation with U.S. Environmental Protection Agency to estimate loads of suspended sediment and trace elements transported through the Clark Fork basin before and after the breach of Milltown Dam. This report presents selected results of the data-collection activities.

  8. Suspended-sediment dynamics in the tidal reach of a San Francisco Bay tributary (United States)

    Shellenbarger, Gregory; Downing-Kunz, Maureen; Schoellhamer, David H.


    To better understand suspended-sediment transport in a tidal slough adjacent to a large wetland restoration project, we deployed continuously measuring temperature, salinity, depth, turbidity, and velocity sensors in 2010 at a near-bottom location in Alviso Slough (Alviso, California, USA). Alviso Slough is the downstream reach of the Guadalupe River and flows into the far southern end of San Francisco Bay. River flow is influenced by the Mediterranean climate, with high flows (∼90 m3 s−1) correlated to episodic winter storms and low base flow (∼0.85 m3 s−1) during the summer. Storms and associated runoff have a large influence on sediment flux for brief periods, but the annual peak sediment concentrations in the slough, which occur in April and May, are similar to the rest of this part of the bay and are not directly related to peak discharge events. Strong spring tides promote a large upstream sediment flux as a front associated with the passage of a salt wedge during flood tide. Neap tides do not have flood-directed fronts, but a front seen sometimes during ebb tide appears to be associated with the breakdown of stratification in the slough. During neap tides, stratification likely suppresses sediment transport during weaker flood and ebb tides. The slough is flood dominant during spring tides, and ebb dominant during neap tides. Extreme events in landward (salt wedge) and bayward (rainfall events) suspended-sediment flux account for 5.0 % of the total sediment flux in the slough and only 0.55 % of the samples. The remaining 95 % of the total sediment flux is due to tidal transport, with an imbalance in the daily tidal transport producing net landward flux. Overall, net sediment transport during this study was landward indicating that sediment in the sloughs may not be flushed to the bay and are available for sedimentation in the adjacent marshes and ponds.

  9. Development of Rating Curve Estimators for Suspended-Sediment Concentration and Transport in the C-51 Canal Based on Surrogate Technology, Palm Beach County, Florida, 2004-05

    National Research Council Canada - National Science Library

    Lietz, A. C; Debiak, Elizabeth A


    .... The major cause of these sediment deposits most likely is due to stormwater heavily laden with fluvial sediment, discharging through the S-155 control structure on the West Palm Beach (C-51) Canal...

  10. Investigating suspended sediment dynamics in contrasting agricultural catchments using ex situ turbidity-based suspended sediment monitoring (United States)

    Sherriff, S. C.; Rowan, J. S.; Melland, A. R.; Jordan, P.; Fenton, O.; hUallachain, D. O.


    Soil erosion and suspended sediment (SS) pose risks to chemical and ecological water quality. Agricultural activities may accelerate erosional fluxes from bare, poached or compacted soils, and enhance connectivity through modified channels and artificial drainage networks. Storm-event fluxes dominate SS transport in agricultural catchments; therefore, high temporal-resolution monitoring approaches are required, but can be expensive and technically challenging. Here, the performance of in situ turbidity sensors, conventionally installed submerged at the river bankside, is compared with installations where river water is delivered to sensors ex situ, i.e. within instrument kiosks on the riverbank, at two experimental catchments (Grassland B and Arable B). The in situ and ex situ installations gave comparable results when calibrated against storm-period, depth-integrated SS data, with total loads at Grassland B estimated at 12 800 and 15 400 t, and 22 600 and 24 900 t at Arable B, respectively. The absence of spurious turbidity readings relating to bankside debris around the in situ sensor and its greater security make the ex situ sensor more robust. The ex situ approach was then used to characterise SS dynamics and fluxes in five intensively managed agricultural catchments in Ireland which feature a range of landscape characteristics and land use pressures. Average annual suspended sediment concentration (SSC) was below the Freshwater Fish Directive (78/659/EEC) guideline of 25 mg L-1, and the continuous hourly record demonstrated that exceedance occurred less than 12 % of the observation year. Soil drainage class and proportion of arable land were key controls determining flux rates, but all catchments reported a high degree of inter-annual variability associated with variable precipitation patterns compared to the long-term average. Poorly drained soils had greater sensitivity to runoff and soil erosion, particularly in catchments with periods of bare soils. Well

  11. Fluvial sediment transport: Analytical techniques for measuring sediment load

    International Nuclear Information System (INIS)


    Sediment transport data are often used for the evaluation of land surface erosion, reservoir sedimentation, ecological habitat quality and coastal sediment budgets. Sediment transport by rivers is usually considered to occur in two major ways: (1) in the flow as a suspended load and (2) along the bed as a bed load. This publication provides guidance on selected techniques for the measurement of particles moving in both modes in the fluvial environment. The relative importance of the transport mode is variable and depends on the hydraulic and sedimentary conditions. The potential user is directed in the selection of an appropriate technique through the presentation of operating principles, application guidelines and estimated costs. Techniques which require laboratory analysis are grab sample, pump sample, depth sample, point integrated and radioactive tracers. Techniques which will continuously record data are optical backscattering, nuclear transmission, single frequency acoustic and laser diffraction

  12. Composite fingerprinting of suspended-sediments in Sorsogon , Philippines

    International Nuclear Information System (INIS)

    Ramirez, J.D.; Sta Maria, E.J.; Madrid, J.F.; Asa, A.D.D.; Aniago, R.J.; Bulos, A.D.; Zombrito, E.Z.


    Sediment-related environmental problems pose a threat not only in land management sustainability but also in management of aquatic ecosystem. Sediments often serve as sinks of nutrients and contaminants that regularly recharge overlying waters and could trigger harmful algal blooms (HAB) together with unfavorable environment conditions. One HAB affected area in the southernmost tip of Luzon, Philippines is Sorsogon Bay. In Sorsogon Bay, the harvest and consumption ban was declared for several years due to the level of toxins in shellfish which exceeded the regulatory limit. Identification of sediment sources is useful tool in planning effective sediment management strategies. A method to determine possible sources of sediment-associated nutrients is sediment fingerprinting. It characterizes land-based sediment sources to derive estimates of the portions of suspended sediment originating from discrete upstream source areas. There are wide ranges of diagnostic properties which can be possible fingerprints such as mineralogic, mineral-magnetic, geochemical, organic, isotopic, physical and radiometric parameters. This study investigates on potential source of sediments from Sampaloc River using different chemical, radiometric and isotopic parameters, Range test and Kruskal-Wallis H-test were employed and indicated that the calcium, titanium, δ”1”3C signal, and to tal carbon content are possible fingerprint parameters that will identify the sources of sediments. Results of a mathematical mixing model showed that channel banks (81.0%) are the largest sediment load contributors in Sampaloc River, followed by cultivated areas (15.5%) and woodlands (3.5%). (author)

  13. Suspended sediment in a high-Arctic river

    DEFF Research Database (Denmark)

    Ladegaard-Pedersen, Pernille; Sigsgaard, Charlotte; Kroon, Aart


    -2012) of daily measurements from the high-Artic Zackenberg River in Northeast Greenland to estimate annual suspended sediment fluxes based on four commonly used methods: M1) is the discharge weighted mean and uses direct measurements, while M2-M4) are one uncorrected and two bias corrected rating curves......-1 and 61,000±16,000ty-1. Extreme events with high discharges had a mean duration of 1day. The average suspended sediment flux during extreme events was 17,000±5000ty-1, which constitutes a year-to-year variation of 20-37% of the total annual flux. The most accurate sampling strategy was bi......-agreements and accuracies sediment concentrations. The discharge weighted mean...

  14. Particle Size Characteristics of Fluvial Suspended Sediment in Proglacial Streams, King George Island, South Shetland Island (United States)

    Szymczak, Ewa


    In this study, the characterization of particle size distribution of suspended sediment that is transported by streams (Ornithologist Creek, Ecology Glacier Creeks, Petrified Forest Creek, Czech Creek, Vanishing Creek, Italian Creek) in the area of the Arctowski Polish Antarctic Station is presented. During the first period of the summer season, the aforementioned streams are supplied by the melting snow fields, while later on, by thawing permafrost. The water samples were collected from the streams at monthly intervals during the Antarctic summer season (January - March) of 2016. The particle size distribution was measured in the laboratory with a LISST-25X laser diffraction particle size analyser. According to Sequoia Scientific Inc., LISST-25X can measure particle sizes (Sauter Mean Diameter) between 2.50 and 500 μm. The results of particle size measurements were analysed in relation to flow velocity (0.18–0.89 m/s), the cross-sectional parameters of the streams, suspended sediment concentration (0.06–167.22 mg/dm3) and the content of particulate organic matter (9.8–84.85%). Overall, the mean particle size ranged from 28.8 to 136 μm. The grain size of well-sorted sediments ranged from 0.076 to 0.57, with the skewness and kurtosis values varying from -0.1 to 0.4, and from 0.67 to 1.3, respectively. Based on the particle size characteristics of suspended sediment, the streams were divided into two groups. For most of the streams, the sediment was very well sorted, while fine sand and very fine sand were dominant fractions displaying symmetric and platykurtic distributions, respectively. Only in two streams, the suspended sediment consisted of silt-size grains, well or moderately well sorted, with coarse-skewness and mostly mesokurtic distribution. The C-M chart suggested that the transportation processes of suspended sediment included the suspended mode only. The grain-size distribution of suspended sediment was mainly influenced by the stream runoff

  15. Suspended-sediment concentrations, loads, total suspended solids, turbidity, and particle-size fractions for selected rivers in Minnesota, 2007 through 2011 (United States)

    Ellison, Christopher A.; Savage, Brett E.; Johnson, Gregory D.


    Sediment-laden rivers and streams pose substantial environmental and economic challenges. Excessive sediment transport in rivers causes problems for flood control, soil conservation, irrigation, aquatic health, and navigation, and transports harmful contaminants like organic chemicals and eutrophication-causing nutrients. In Minnesota, more than 5,800 miles of streams are identified as impaired by the Minnesota Pollution Control Agency (MPCA) due to elevated levels of suspended sediment. The U.S. Geological Survey, in cooperation with the MPCA, established a sediment monitoring network in 2007 and began systematic sampling of suspended-sediment concentrations (SSC), total suspended solids (TSS), and turbidity in rivers across Minnesota to improve the understanding of fluvial sediment transport relations. Suspended-sediment samples collected from 14 sites from 2007 through 2011 indicated that the Zumbro River at Kellogg in the driftless region of southeast Minnesota had the highest mean SSC of 226 milligrams per liter (mg/L) followed by the Minnesota River at Mankato with a mean SSC of 193 mg/L. During the 2011 spring runoff, the single highest SSC of 1,250 mg/L was measured at the Zumbro River. The lowest mean SSC of 21 mg/L was measured at Rice Creek in the northern Minneapolis- St. Paul metropolitan area. Total suspended solids (TSS) have been used as a measure of fluvial sediment by the MPCA since the early 1970s; however, TSS concentrations have been determined to underrepresent the amount of suspended sediment. Because of this, the MPCA was interested in quantifying the differences between SSC and TSS in different parts of the State. Comparisons between concurrently sampled SSC and TSS indicated significant differences at every site, with SSC on average two times larger than TSS concentrations. The largest percent difference between SSC and TSS was measured at the South Branch Buffalo River at Sabin, and the smallest difference was observed at the Des Moines

  16. Numerical Simulations of Suspended Sediment Dynamics Due to Seasonal Forcing in the Mekong Coastal Area

    Directory of Open Access Journals (Sweden)

    Vu Duy Vinh


    Full Text Available The Mekong River is ranked as the 8th in terms of water discharge and as the 10th in terms of sediment load in the world. During the last 4500 years, its delta prograded more than 250 km to the south due to a tremendous amount of sediments deposited, and turned from a “tide-dominated” delta into a “wave-and-tide dominated” delta. This study aims at completing our knowledge on the fate of sediments that may be stored in estuarine or coastal systems, or dispersed over the continental shelf and slope. Sediment transport in the Mekong River Delta (MRD coastal area was studied by numerical simulations using the Delft3D model. The model configuration was calibrated and validated from data collected in situ during 4 periods from 2012 to 2014. Then, 50 scenarios corresponding to different wave conditions (derived from the wave climate and river discharge values typical of low flow and flood seasons enabled us to quantify the dispersal patterns of fluvial sediments close to the mouths and along the coast. Sediments mostly settled in the estuary and close to the mouths under calm conditions, and suspended sediment with higher concentrations extend further offshore with higher waves. Waves from the Southeast enhanced the concentration all along the MRD coastal zone. Waves from the South and Southwest induced coastal erosion, higher suspended sediment concentrations in front of the southern delta, and a net transport towards the Northeast of the delta. Because of episodes of Southern and Southwestern waves during the low flow season, the net alongshore suspended sediment transport is oriented Northeastward and decreases from the Southwestern part of the coastal zone (~960 × 103 t yr−1 to the Northeastern part (~650 × 103 t yr−1.

  17. Event-based total suspended sediment particle size distribution model (United States)

    Thompson, Jennifer; Sattar, Ahmed M. A.; Gharabaghi, Bahram; Warner, Richard C.


    One of the most challenging modelling tasks in hydrology is prediction of the total suspended sediment particle size distribution (TSS-PSD) in stormwater runoff generated from exposed soil surfaces at active construction sites and surface mining operations. The main objective of this study is to employ gene expression programming (GEP) and artificial neural networks (ANN) to develop a new model with the ability to more accurately predict the TSS-PSD by taking advantage of both event-specific and site-specific factors in the model. To compile the data for this study, laboratory scale experiments using rainfall simulators were conducted on fourteen different soils to obtain TSS-PSD. This data is supplemented with field data from three construction sites in Ontario over a period of two years to capture the effect of transport and deposition within the site. The combined data sets provide a wide range of key overlooked site-specific and storm event-specific factors. Both parent soil and TSS-PSD in runoff are quantified by fitting each to a lognormal distribution. Compared to existing regression models, the developed model more accurately predicted the TSS-PSD using a more comprehensive list of key model input parameters. Employment of the new model will increase the efficiency of deployment of required best management practices, designed based on TSS-PSD, to minimize potential adverse effects of construction site runoff on aquatic life in the receiving watercourses.

  18. Interactions of radionuclides with sediments and suspended particles

    International Nuclear Information System (INIS)

    Carpenter, R.


    This chapter reviews fundamental principles of the rates and extents of radionuclide uptake by sedimentary and suspended particles, defines sediment-water partition coefficients, and shows how they can explain first order features of radionuclide partitioning in aquatic environments. It then explains how sediment accumulation and mixing rates can be calculated from profiles of radionuclide activity measured in sediment cores. Such rates can be combined with profiles of other chemicals to establish the extent of temporal changes in chemical composition of the overlying water body. Since sediment processing and counting in the laboratory take much longer than the time required to collect the sample, suggestions are made to ensure that the sediment samples are not ruined or comprised during collection and handling in the field, and so are worth all the subsequent time and effort to analyze. (author)

  19. Sediment transport in an active erodible channel bend

    Indian Academy of Sciences (India)

    Local variation of sediment transport is primarily controlled by active bank erosion, land spur and sand bar formation. Vertical distribution of suspended sediment concentration follows a power function with normalized depth. Average bed-material concentration at the reach level is computed from observed sediment profiles, ...

  20. System Identification Theory Approach to Cohesive Sediment Transport Modelling




    Two aspects of the modelling sediment transport are investigated. One is the univariate time series modelling the current velocity dynamics. The other is the multivariate time series modelling the suspended sediment concentration dynamics. Cohesive sediment dynamics and numerical sediment transport model are reviewed and investigated. The system identification theory and time series analysis method are developed and applied to set up the time series model for current velocity a...

  1. Chemical composition of sediments, suspended matter, river water and ground water of the Nile (Aswan-Sohag traverse). (United States)

    Dekov, V M; Komy, Z; Araújo, F; Van Put, A; Van Grieken, R


    Sediment, suspended matter, river water and ground water samples were collected at twelve sites in the drainage valley of the Nile River, around Sohag (Central Egypt) and close to the Aswan High Dam. Elemental composition of the river water (27 elements), ground water (eight elements), suspended matter (12 elements) and sediments (12 elements) was studied. Aswan High Dam construction, agricultural and industrial human activities have led to dramatic changes in the Nile River chemistry. Nowadays, the Nile River has the highest dissolved salt content among the major African rivers. Dissolved transport is a major process for Ca, K, Sr, Zn, Cu, Ni and V. Manganese, Fe and Cr are mainly carried by suspended matter. The Nile suspended matter is exhausted in almost all elements studied (except for Mn) compared to the world average river suspended matter. Along the course of the river, the distribution of elements in the suspended matter and sediments is generally controlled by natural processes: the relative importance of elemental transport phases; and the oxidation, precipitation and sedimentation of mineral species through the varying physico-chemical conditions of the environment. Pollution input in the Nile particulate load is not major, as compared to the natural inputs. Eight genetic particle types describe the composition of the Nile suspended matter and sediments: (1) biogenous-aeolian (or silica); (2) terrigenous (Fe-aluminosilicate); (3) authigenic (calcium carbonate); (4) biogenous (apatite); (5) authigenous-terrigenous (Fe-oxyhydroxide-montmorillonite); (6) diagenetic (iron-sulfide); (7) terrigenous (titanium oxide); (8) authigenous (Mn-Fe-oxyhydroxide).

  2. Aeolian Sediment Availability and Transport

    NARCIS (Netherlands)

    Hoonhout, B.M.


    This thesis explores the nature of aeolian sediment availability and its influence on aeolian sediment transport. The aim is to improve large scale and long term aeolian sediment transport estimates in (nourished) coastal environments. The generally poor performance of aeolian sediment transport

  3. Do suspended sediment and bedload move progressively from the summit to the sea along Magela Creek, northern Australia?

    Directory of Open Access Journals (Sweden)

    W. D. Erskine


    Full Text Available Soil erosion rates on plots of waste rock at Ranger uranium mine and basin sediment yields have been measured for over 30 years in Magela Creek in northern Australia. Soil erosion rates on chlorite schist waste rock are higher than for mica schist and weathering is also much faster. Sediment yields are low but are further reduced by sediment trapping effects of flood plains, floodouts, billabongs and extensive wetlands. Suspended sediment yields exceed bedload yields in this deeply weathered, tropical landscape, but the amount of sand transported greatly exceeds that of silt and clay. Nevertheless, sand is totally stored above the topographic base level. Longitudinal continuity of sediment transport is not maintained. As a result, suspended sediment and bedload do not move progressively from the summit to the sea along Magela Creek and lower Magela Creek wetlands trap about 90.5% of the total sediment load input.

  4. Sediment transport mechanics (United States)

    Ballio, Francesco; Tait, Simon


    The Editor of Acta Geophysica and the Guest Editors wish to dedicate this Topical Issue on Sediment Transport Mechanics to the memory of Stephen Coleman, who died recently. During his career, Stephen had made an outstanding scientific contribution to the topic of Sediment Transport. The level of his contribution is demonstrated in the paper by Aberle, Coleman, and Nikora included in this issue, on which he started working before becoming aware of the illness that led to his untimely death. For scholars and colleagues Stephen remains an example of intellectual honesty and scientific insight.

  5. Suspended-sediment concentrations, yields, total suspended solids, turbidity, and particle-size fractions for selected rivers in Minnesota, 2007 through 2011 (United States)

    Ellison, Christopher A.; Savage, Brett E.; Johnson, Gregory D.


    Excessive sediment transport in rivers causes problems for flood control, soil conservation, irrigation, aquatic health, and navigation, as well as transporting harmful contaminants like organic chemicals and eutrophication-causing nutrients. In Minnesota, more than 5,800 miles of streams are identified as impaired by the Minnesota Pollution Control Agency (MPCA) due to elevated levels of suspended sediment. The U.S. Geological Survey, in cooperation with the MPCA, established a sediment monitoring network in 2007 and began systematic sampling of suspended-sediment concentration (SSC), total suspended solids (TSS), and turbidity in rivers across Minnesota to improve the understanding of fluvial sediment transport relations. Suspended-sediment samples were collected from 14 sites from 2007 through 2011. Analyses of these data indicated that the Zumbro River at Kellogg in southeast Minnesota had the highest mean SSC of 226 milligrams per liter (mg/L) followed by the Minnesota River at Mankato with a mean SSC of 193 mg/L. The single highest SSC of 1,250 mg/L was measured at the Zumbro River during the 2011 spring runoff. The lowest mean SSC of 21 mg/L was measured at Rice Creek in the northern Minneapolis-St. Paul metropolitan area. Total suspended solids (TSS) have been used as a measure of fluvial sediment by the MPCA since the early 1970s; however, TSS concentrations have been known to underrepresent the amount of suspended sediment. For this study, comparisons between concurrently sampled SSC and TSS indicated significant differences at every site, with SSC on average two times larger than TSS concentrations. Regression analysis indicated that 7 out of 14 sites had poor or no relation between SSC and streamflow. Only two sites, the Knife River and the Wild Rice River at Twin Valley, had strong correlations between SSC and streamflow, with coefficient of determination (R2) values of 0.82 and 0.80, respectively. In contrast, turbidity had moderate to strong

  6. Dynamics of suspended sediment concentration, flow discharge and sediment particle size interdependency to identify sediment source (United States)

    Sadeghi, Seyed Hamidreza; Singh, Vijay P.


    Spatiotemporal behavior of sediment yield is a key for proper watershed management. This study analyzed statistical characteristics and trends of suspended sediment concentration (SCS), flow discharge (FD) and sediment particle sizes using data from 24 gage stations scattered throughout the United States. Analysis showed significant time- and location-specific differences of these variables. The median values of SSC, FD and percentage of particle sizes smaller than 63 μm (P63) for all 24 gage stations were found to be 510.236 mg l-1 (right skewed), 45.406 m3 s-1 (left skewed) and 78.648% (right skewed), respectively. Most of the stations exhibited significant trends (P type and erosivity, watershed area, and soil erodibility) and human-affected (i.e., land use and hydraulic structures and water resources management) factors governing the study variables.

  7. Measurements of Sediment Erosion and Transport with the ASSET Flume (United States)

    Jepsen, R. A.; Roberts, J. D.; James, S. C.


    Soil and sediments play an important role in water management and water quality. Issues such as water turbidity, associated contaminants, reservoir sedimentation, undesirable erosion and scour, and aquatic habitat are all linked to sediment properties and behaviors. In situ analysis is necessary to develop an understanding of the erosion and transport of sediments. Sandia National Laboratories has recently patented the ASSET Flume that quantifies in situ erosion of a sediment core with depth while affording simultaneous examination of transport modes (bedload vs. suspended load) of the eroded material. Core erosion rates and ratios of bedload to suspended load transport of quartz sediments were studied with the ASSET Flume. The erosion and transport of a fine-grained natural cohesive sediment were also observed. Experiments using quartz sands revealed that the ratio of suspended load to bedload sediment transport is a function of grain diameter and shear stress at the sediment surface. Data collected from the ASSET Flume were used to formulate a novel empirical relation for predicting the ratio of bedload to suspended load as a function of shear stress and grain diameter for non-cohesive sediments.

  8. Distribution of suspended sediment in the coastal sea off the Ganges Brahmaputra River mouth: observation from TM data (United States)

    Islam, Mohammad Rezwanul; Begum, Syeda Fahliza; Yamaguchi, Yasushi; Ogawa, Katsuro


    Remote sensing technique was applied to estimate suspended sediment concentration (SSC) and to understand transportation, distribution and deposition of suspended sediment in the estuary and throughout the coastal sea, off the Ganges-Brahmaputra River mouth. During low river discharge period, zone of turbidity maximum is inferred in the estuary near the shore. SSC map shows that maximum SSC reaches 1050 mg/l in this period. Magnitude of SSC is mainly owing to resuspension of the bottom surface sediments induced by tidal currents flowing over shallow water depths. The influence of depth on resuspension is farther revealed from the distribution and magnitude of SSC along the head of Swatch of No Ground (SNG) submarine canyon. During high river discharge period, huge river outflow pushed the salt wedge and flashes away the suspended sediments in the coastal sea off the river mouth. Zone of turbidity maximum is inferred in the coastal water approximately within 5-10 m depth of water, where the maximum SSC reaches 1700 mg/l. In this period, huge fluvial input of the suspended sediments including the resuspended bottom sediments and the particles remaining in suspension for longer period of time since their initial entry control mainly the magnitude of SSC. In the estuary near the shore, seasonal variation in the magnitude of SSC is not evident. In the coastal sea (>5 m water depth), seasonal influence in the magnitude of SSC could be concluded from the discrepancy between SSC values of two different seasons. Transportation and deposition of suspended sediments also experiences seasonal variations. At present, suspended sediments are being accumulated on the shallow shelf (between 5 and 10 m water depth) in low discharge period and on the mid-shelf (between 10 and 75 m water depth) during high discharge period. An empirical (exponential) relationship was found between gradual settle down of suspended sediments in the coastal sea and its lateral distance from the

  9. Comparability of river suspended-sediment sampling and laboratory analysis methods (United States)

    Groten, Joel T.; Johnson, Gregory D.


    Accurate measurements of suspended sediment, a leading water-quality impairment in many Minnesota rivers, are important for managing and protecting water resources; however, water-quality standards for suspended sediment in Minnesota are based on grab field sampling and total suspended solids (TSS) laboratory analysis methods that have underrepresented concentrations of suspended sediment in rivers compared to U.S. Geological Survey equal-width-increment or equal-discharge-increment (EWDI) field sampling and suspended sediment concentration (SSC) laboratory analysis methods. Because of this underrepresentation, the U.S. Geological Survey, in collaboration with the Minnesota Pollution Control Agency, collected concurrent grab and EWDI samples at eight sites to compare results obtained using different combinations of field sampling and laboratory analysis methods.Study results determined that grab field sampling and TSS laboratory analysis results were biased substantially low compared to EWDI sampling and SSC laboratory analysis results, respectively. Differences in both field sampling and laboratory analysis methods caused grab and TSS methods to be biased substantially low. The difference in laboratory analysis methods was slightly greater than field sampling methods.Sand-sized particles had a strong effect on the comparability of the field sampling and laboratory analysis methods. These results indicated that grab field sampling and TSS laboratory analysis methods fail to capture most of the sand being transported by the stream. The results indicate there is less of a difference among samples collected with grab field sampling and analyzed for TSS and concentration of fines in SSC. Even though differences are present, the presence of strong correlations between SSC and TSS concentrations provides the opportunity to develop site specific relations to address transport processes not captured by grab field sampling and TSS laboratory analysis methods.

  10. Mesoscale eddies transport deep-sea sediments. (United States)

    Zhang, Yanwei; Liu, Zhifei; Zhao, Yulong; Wang, Wenguang; Li, Jianru; Xu, Jingping


    Mesoscale eddies, which contribute to long-distance water mass transport and biogeochemical budget in the upper ocean, have recently been taken into assessment of the deep-sea hydrodynamic variability. However, how such eddies influence sediment movement in the deepwater environment has not been explored. Here for the first time we observed deep-sea sediment transport processes driven by mesoscale eddies in the northern South China Sea via a full-water column mooring system located at 2100 m water depth. Two southwestward propagating, deep-reaching anticyclonic eddies passed by the study site during January to March 2012 and November 2012 to January 2013, respectively. Our multiple moored instruments recorded simultaneous or lagging enhancement of suspended sediment concentration with full-water column velocity and temperature anomalies. We interpret these suspended sediments to have been trapped and transported from the southwest of Taiwan by the mesoscale eddies. The net near-bottom southwestward sediment transport by the two events is estimated up to one million tons. Our study highlights the significance of surface-generated mesoscale eddies on the deepwater sedimentary dynamic process.

  11. An inventory of suspended sediment stations and type of data analysis for Pennsylvania streams, 1947-1970 (United States)

    Ott, Arthur N.; Commings, Allen B.


    Data concerning suspended sediment concentrations and loads, frequency of occurrence of suspended sediment concentrations, and long-term trends of annual suspended sediment loads are important tools for today's environmental manager. These data are required background for those concerned with establishing and enforcing erosion and sedimentation control regulations and sediment concentration or turbidity standards for water-quality criteria, or those concerned with designing for adequate long-term water storage in reservoirs (sediment load), for efficient municipal and industrial plant operation (sediment concentration frequency), etc.This is a compilation of the location, period of record, sampling frequency and type of data synthesis for suspended sediment carried by Pennsylvania streams. Figures 1 and 2 show the approximate locations of sediment sampling stations in Pennsylvania. All of the sediment data listed were collected by the U. S. Geological Survey mainly in cooperation with the following Federal, State, and local agencies.Pennsylvania Department of Environmental Resources     Bureau of Engineering and Construction     Soil and Water Conservation CommissionPennsylvania Department of TransportationCity of PhiladelphiaBrandywine Valley AssociationDelaware Geological SurveyConestoga Valley AssociationLehigh County Soil and Water Conservation DistrictCorps of Engineers, U. S. Army

  12. Water and suspended sediment dynamics in Selangor River estuary

    International Nuclear Information System (INIS)

    Abdul Kadir Ishak; Kamarudin Samuding; Nazrol Hizam Yusoff


    Observations of salinity, temperature, suspended sediment concentration (SSC) and tidal current velocity were made in the lower and along the longitudinal axis of Sungai Selangor estuary over neap-spring cycles. The variations of these parameters at the measurement stations and along the channel are presented to illustrate the water and sediment dynamics in the estuary. The results shows that the Sungai Selangor estuary changes from a partially-mixed type during neaps to a well-mixed one during springs, promoted by stronger tidal energy during the higher tidal ranges. The strong neap density stratification is also promoted by the high river discharges during the measurement period. Maximum concentration of suspended sediment (> 2000 mg/l) occurs during maximum current velocities both during flood and ebb. The maximum salinity was achieved during high water slack but the salt water was totally flushed out of estuary during low water springs. The longitudinal axis measurement indicates that a partially-developed zone of turbidity maximum with a sediment concentration over 1000 mg/l was observed at the limit of salt water intrusion in salinity range less than 1 ppt. Tidal pumping as oppose to the estuarine circulation is the more dominant factor in the maximum formation as the salt water is totally excluded at low water. (Author)

  13. Calibration of Optical Back Scatterance for Suspended Sediment Concentration With San Francisco Bay Sediment (United States)

    Keller, B.


    Optical back scatterance (OBS) is used by USGS to indirectly quantify suspended sediment concentration in the waters of San Francisco Bay. The use of one of the types of OBS instruments that is used in the Bay was evaluated for quantification of discharge water from sand yards, where dredged bay floor sand is brought on land for commercial purposes. The instrument response was calibrated with synthetic samples prepared from settled, previously suspended fine sediment, collected on various dates and derived from the same general area of central San Francisco Bay. The sediment samples were washed with fresh water, oven dried, sieved, and mixed into water in a test chamber. The responses of various sediment samples were compared with that of silica flour, a commercially available industrial material with similar particle size and density, that is white in color. Multiple tests with sediment samples from individual dates yielded extremely repeatable, almost linear instrument responses as a function of varying concentration. Sediment samples from different dates yielded varying responses, ranging from 2.0 to 2.8 times the response of silica flour. This response difference, a factor of approximately 1.4, is interpreted to be due to small differences in the darkness ("color") of the sediment samples. In a comparison with an EPA test method that uses filtration and weighing, performed at commercial laboratories, the "total suspended solids" (TSS, used synonymously with the term "suspended sediment concentration") analyses of the mixed synthetic sample waters yielded very poor results. Saline water samples were often associated with TSS test results that were higher than the known synthetic sample concentrations, indicating that the lab tests were often measuring dissolved salt rather than suspended sediment.

  14. Suspended-sediment and suspended-sand concentrations and loads for selected streams in the Mississippi River Basin, 1940-2009 (United States)

    Heimann, David C.; Cline, Teri L.; Glaspie, Lori M.


    This report presents suspended-sediment concentration and streamflow data, describes load-estimation techniques used in the computation of annual suspended-sediment loads, and presents annual suspended-sediment loads for 48 streamgaging stations within the Mississippi River Basin. Available published, unpublished, and computed annual total suspended-sediment and suspended-sand loads are presented for water years 1940 through 2009. When previously published annual loads were not available, total suspended-sediment and sand loads were computed using available data for water years 1949 through 2009. A table of suspended-sediment concentration and daily mean streamflow data used in the computation of annual loads is presented along with a table of compiled and computed annual suspended-sediment and suspended-sand loads, annual streamflows, and flow-weighted concentrations for the 48 stations.

  15. Quantification of suspended sediment transfers in a lowland agricultural catchment (United States)

    Salvador-Blanes, Sebastien; Manière, Louis; Grangeon, Thomas; Cerdan, Olivier; Evrard, Olivier; Foucher, Anthony; Vandromme, Rosalie


    Lowland agricultural landscapes underwent important changes since the second half of the XXth century such as hedges removal, implementation of drainage systems, stream redesign and land reallocation. It resulted in changes in sediment transfer processes, and in widespread morphological alterations of water bodies. However, little is known about the sediment dynamics in these environments. The Louroux catchment (25 km2) is located in central France. It is a typical intensively cultivated and tile drained lowland catchment. The Xth century pond located at its outlet (52 ha) is undergoing large siltation, with a current sedimentation rate 60 fold higher than the pre-1950 period. Five monitoring stations, measuring water levels and turbidity at high frequency (15 mn and 1 mn respectively), combined with automatic samplers, were implemented in 2013. Three stations are located at the main tributaries outlets of the pond, one in a sub-catchment, and one at a tile drain outlet. 45 floods were observed during the three studied hydrological years. They occurred mostly between December and March (33 floods) and in May-June (8 floods). Specific sediment yields ranged from 0.02 to 0.38 t.ha-1.yr-1 depending on the monitoring site and the considered year. The vast majority of suspended sediment transfers occur during the winter floods. While large water volumes were also measured during spring floods, the sediment yields remained low. Suspended sediment yields present large inter-annual (ratio ranging between 2 and 6 depending on the monitoring station) and spatial variations, due to significant differences in total rainfall amounts during the winter season and variations in land use, respectively. The processes related to sediment transfers are most likely linked to soil saturation during winter despite the presence of a tile drainage network, with transfers occurring both at the soil surface and through the drainage system. While sediment transfer rates can be considered as

  16. Characteristics of sediment data and annual suspended-sediment loads and yields for selected lower Missouri River mainstem and tributary stations, 1976-2008 (United States)

    Heimann, David C.; Rasmussen, Patrick P.; Cline, Teri L.; Pigue, Lori M.; Wagner, Holly R.


    Suspended-sediment data from 18 selected surface-water monitoring stations in the lower Missouri River Basin downstream from Gavins Point Dam were used in the computation of annual suspended-sediment and suspended-sand loads for 1976 through 2008. Three methods of suspended-sediment load determination were utilized and these included the subdivision method, regression of instantaneous turbidity with suspended-sediment concentrations at selected stations, and regression techniques using the Load Estimator (LOADEST) software. Characteristics of the suspended-sediment and streamflow data collected at the 18 monitoring stations and the tabulated annual suspended-sediment and suspended-sand loads and yields are presented.

  17. Geomorphic versus land use controls on suspended sediment rating curves (United States)

    Belmont, P.; Vaughan, A. A.; Fisher, A. C. N.


    The relation between river discharge (Q) and suspended sediment (SS) concentration reflects the degree to which sediment sources are accessed or depleted across the range of flow conditions. Increased availability of high resolution topography and land use data greatly enhance our ability to evaluate linkages between characteristics of these sediment rating curves (SRCs) and the geomorphic features that influence them. We evaluated Q-SS relations at 45 gages throughout Minnesota, USA representing a wide variety of landscape settings in terms of topography, land use, and geologic history. We characterized the SRCs according to the overall shape, steepness (exponent), vertical offset (coefficient) and SS concentration under low flow (90% exceedance) conditions. Rivers exhibited three distinct SRC shapes, simple power functions, threshold power functions and peaked power functions. We used random forest models to analyze relations between SRC parameters and attributes of the watershed as well as the near-channel environment. The model correctly classified 78% of SRC shapes and explained 60% of variance in the SRC exponent, 43% of the SRC coefficient for rising limb samples, and 45% of variance under low flow conditions. Notably, the random forest models predict that near-channel morphology predominately controls both the shape and steepness of the sediment rating curves. Land use predominately controls the vertical offset (coefficient) and SS concentration under low flow conditions. These findings suggest that land use and watershed restoration practices may have little capacity to alter the shape and steepness of these curves as these characteristics may be dictated by the geologic and geomorphic setting. Rather, human influences in the watershed may exhibit the greatest influence on suspended sediment concentrations at moderate to low flows. Criteria to evaluate improvements in water quality as a result of changes in land management might be most meaningful if they

  18. Variability of suspended sediment yields within the Loire river basin (France) (United States)

    Gay, A.; Cerdan, O.; Delmas, M.; Desmet, M.


    Suspended sediment fluxes and their variability in time and space have received much attention over the past decades. Large databases compiling suspended sediment load (SL) data are often used to serve these purposes. Analyses of these databases have highlighted the following two major limitations: (i) the role of lowland areas in sediment production and transfer has been minimised, and studies on small-scale catchments (with a drainage area of ⩽ 102 km2) are practically non-existent in the literature; and (ii) inhomogeneous data and calculation methods are used to estimate and compare the SL values. In this context, the present study aims to complete the existing studies by providing a reliable comparison of SL values for various catchments within lowland river basins. Therefore, we focused on the Loire and Brittany river basins (France). 111 small to large catchments covering 78% of this area and representative of the basins landscape diversity were chosen. We first present a large database of area-specific suspended sediment yields (SY) calculated from the suspended sediment concentration and flow discharge data over 7-40 yr of measurements at gauging stations. Two calculation methods are used, and the calculated loads are confined within a factor of 0.60-1.65 of the real values. Second, we analyse the temporal and spatial variability of the calculated SY values. Finally, using a nested catchment approach, we provide insight into sediment transport from upstream to downstream gauging stations and into the role of small- and medium- scale catchments in sediment production and transfers. The SL values at the outlet of the catchments range from 2.5 * 102 to 8.6 * 105 t yr-1, and the SY values range from 2.9 to 32.4 t km-2 yr-1. A comparison with the limited values available in the literature for this region corroborates our estimations. Sediment exports from the Loire and Brittany river basins are very low compared with mountainous regions and European exports

  19. Estimation of suspended sediment concentration from turbidity measurements for agrarian watersheds of Navarre (Spain) (United States)

    Madrona, Cecilia; Campo-Bescós, Miguel A.; Giménez, Rafael


    Studies of soil erosion at watershed scales have addressed this phenomenon from a holistic perspective, linking and prioritizing the dominant influence of the different factors involved in this complex process. Thus, the pattern of sediment transport in a watershed is an excellent indicator of the type and intensity of the dominant erosion processes as well as of the relationships between precipitation, infiltration and runoff. An optimal characterization of the dynamics of sediment requires reliable measurements and recording of the suspended sediment concentration (SSC) at the watershed outlet at a small time scale (minutes) since SSC normally fluctuates rapidly during storm events. But the latter is economically feasible only through indirect measurements; for example, by using turbidimeter. In fact, turbidity is a common subrogate of suspended sediment concentration; but for this purpose it is necessary first to define a suitable (empirical) turbidity-SSC model. But this is not an easy task since the wide range of possible suspended particles of different nature and composition (e.g., silt, clay, organic matter and microorganisms) often lead to a weak association between SSC and turbidity. In Navarre (Spain), soil erosion is an important problem affecting agricultural land. For this reason, the local Government owns and maintains a network of four experimental watersheds to assess the impact on the environment of typical agrarian activities. So that, the amount of sediment and solutes evacuated at the exit of each watershed has been recorded, along with other relevant hydrological and meteorological data. Furthermore, turbidity has been measured every ten minutes. But turbidity-SSC model - determined from average daily data of SSC- currently in use is unsatisfactory, especially for spring and summer events. The aim of this study is to find an appropriate turbidity-SSC relationship for (each of) the agrarian experimental watersheds of Navarre. Regression

  20. Sediment acoustic index method for computing continuous suspended-sediment concentrations (United States)

    Landers, Mark N.; Straub, Timothy D.; Wood, Molly S.; Domanski, Marian M.


    Suspended-sediment characteristics can be computed using acoustic indices derived from acoustic Doppler velocity meter (ADVM) backscatter data. The sediment acoustic index method applied in these types of studies can be used to more accurately and cost-effectively provide time-series estimates of suspended-sediment concentration and load, which is essential for informed solutions to many sediment-related environmental, engineering, and agricultural concerns. Advantages of this approach over other sediment surrogate methods include: (1) better representation of cross-sectional conditions from large measurement volumes, compared to other surrogate instruments that measure data at a single point; (2) high temporal resolution of collected data; (3) data integrity when biofouling is present; and (4) less rating curve hysteresis compared to streamflow as a surrogate. An additional advantage of this technique is the potential expansion of monitoring suspended-sediment concentrations at sites with existing ADVMs used in streamflow velocity monitoring. This report provides much-needed standard techniques for sediment acoustic index methods to help ensure accurate and comparable documented results.

  1. Sediment transport and depth variation study of the Gulf of Kutch using remote sensing

    Digital Repository Service at National Institute of Oceanography (India)

    Kunte, P.D.; Wagle, B.G.; Sugimori, Y.

    of actual data and principal components were generated to study sediment transport, depth variation and associated processes by mapping coastal and underwater geomorphic features and suspended sediment plumes. Submerged shoals, located as deep as 20 m below...

  2. Sediment transport in two mediterranean regulated rivers. (United States)

    Lobera, G; Batalla, R J; Vericat, D; López-Tarazón, J A; Tena, A


    Mediterranean climate is characterized by highly irregular rainfall patterns with marked differences between wet and dry seasons which lead to highly variable hydrological fluvial regimes. As a result, and in order to ensure water availability and reduce its temporal variability, a high number of large dams were built during the 20th century (more than 3500 located in Mediterranean rivers). Dams modify the flow regime but also interrupt the continuity of sediment transfer along the river network, thereby changing its functioning as an ecosystem. Within this context, the present paper aims to assess the suspended sediment loads and dynamics of two climatically contrasting Mediterranean regulated rivers (i.e. the Ésera and Siurana) during a 2-yr period. Key findings indicate that floods were responsible for 92% of the total suspended sediment load in the River Siurana, while this percentage falls to 70% for the Ésera, indicating the importance of baseflows on sediment transport in this river. This fact is related to the high sediment availability, with the Ésera acting as a non-supply-limited catchment due to the high productivity of the sources (i.e. badlands). In contrast, the Siurana can be considered a supply-limited system due to its low geomorphic activity and reduced sediment availability, with suspended sediment concentration remaining low even for high magnitude flood events. Reservoirs in both rivers reduce sediment load up to 90%, although total runoff is only reduced in the case of the River Ésera. A remarkable fact is the change of the hydrological character of the River Ésera downstream for the dam, shifting from a humid mountainous river regime to a quasi-invariable pattern, whereas the Siurana experiences the opposite effect, changing from a flashy Mediterranean river to a more constant flow regime below the dam. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Ratios of total suspended solids to suspended sediment concentrations by particle size (United States)

    Selbig, W.R.; Bannerman, R.T.


    Wet-sieving sand-sized particles from a whole storm-water sample before splitting the sample into laboratory-prepared containers can reduce bias and improve the precision of suspended-sediment concentrations (SSC). Wet-sieving, however, may alter concentrations of total suspended solids (TSS) because the analytical method used to determine TSS may not have included the sediment retained on the sieves. Measuring TSS is still commonly used by environmental managers as a regulatory metric for solids in storm water. For this reason, a new method of correlating concentrations of TSS and SSC by particle size was used to develop a series of correction factors for SSC as a means to estimate TSS. In general, differences between TSS and SSC increased with greater particle size and higher sand content. Median correction factors to SSC ranged from 0.29 for particles larger than 500m to 0.85 for particles measuring from 32 to 63m. Great variability was observed in each fraction-a result of varying amounts of organic matter in the samples. Wide variability in organic content could reduce the transferability of the correction factors. ?? 2011 American Society of Civil Engineers.

  4. Mixing Model Analysis of Suspended Sediment and Particulate Organic Carbon Sources in White Clay Creek, Pennsylvania (United States)

    Karwan, D. L.; Aufdenkampe, A. K.; Aalto, R. E.; Marquard, J.; Pizzuto, J. E.; Newbold, J. D.


    Material exports from watersheds have consequences to upstream catchment elemental budgets, downstream ecosystem processes and water resources management. Despite this importance, quantifying exports of all major and trace elements associated with suspended sediments is challenging due to the highly episodic nature of that export. Constraining sediment sources using various mixing model approaches is further complicated by the diversity of potential sources. In this study, we leveraged the infrastructure of the Christina River Basin Critical Zone Observatory (CRB-CZO) to collect large volume (200 L) samples from 17 storms, including some of the biggest storms of the decade (i.e. Hurricane Irene and Sandy), and 95 potential source soils and sediments within the White Clay Creek watershed, a third-order watershed in southeastern Pennsylvania. On all samples we analyzed major and minor elements, rare earth elements, and radioisotopes in order to determine the erosional source category of stream suspended material, such that differences in the chemical composition of source materials can be used in a multivariate statistical model to predict the chemical composition of suspended sediment. For example, 137Cs is higher in surface and near-surface terrestrial soils and low in streambanks, deeper soils, road cuts, and road dust. Elemental chromium is much higher in road dust than any other source. We integrate sediment fingerprinting analyses common in geomorphological studies of mineral suspended material with biological and ecological characterizations of particulate organic carbon. Through this combination, we determine particle source, a necessary first step to calculating the amount of excess carbon that has complexed with particles during erosion and transit through the watershed. This interdisciplinary project is conducted as one of many studies in the CRB-CZO and directly contributes to the overall research focus of this CZO: to quantify the net carbon sink or

  5. Contemporary suspended sediment yield of a partly glaciated catchment, Riffler Bach (Tyrol, Austria) (United States)

    Weber, Martin; Baewert, Henning; Morche, David


    Due to glacier retreat since the LIA (Little Ice Age) proglacial areas in high mountain landscapes are growing. These systems are characterized by a high geomorphological activity, especially in the fluvial subsystem. Despite the long tradition of geomorphological research in the European Alps there is a still a lack of understanding in the interactions between hydrology, sediment sources, sediments sinks and suspended sediment transport. As emphasized by ORWIN ET AL. (2010) those problems can be solved by gathering data in a higher frequency and/or in a higher spatial resolution or density - both leading to a big amount of data. In 2012 a gauging station was installed at the outlet of the partly glaciated catchment of the Riffler Bach (Kaunertal valley, Tyrol). During the ablation seasons in 2012 and 2013 water stage was logged automatically every 15 minutes. In both seasons discharge was measured at different water levels to calculate a stage-discharge relation. Additionally, water samples were taken by an automatic water sampler. Within 16 sampling cycles with sampling frequencies ranging from 1 to 24 hours 389 water samples have been collected. The samples were filtered to calculate the suspended sediment concentration (SSC) of each sample. Furthermore, the climate station Weißsee provided meteorological data at a 15 minute interval. Due to the high variability in suspended sediment transport in proglacial rivers it is impossible to compute a robust annual Q-SSC-relation. Hence, two other approaches were used to calculate the suspended sediment load (SSL) and the suspended sediment yield (SSY): A) Q-SSC-relations for every single sampling cycle (e.g. GEILHAUSEN ET AL. 2013) B) Q-SSC-relations based on classification of dominant runoff-generating processes (e.g. ORWIN AND SMART 2004). The first approach uses commonly operated analysis methods that are well understood. While the hydro-climatic approach is more feasible to explain discharge generation and to

  6. Remote sensing of suspended sediment water research: principles, methods, and progress (United States)

    Shen, Ping; Zhang, Jing


    In this paper, we reviewed the principle, data, methods and steps in suspended sediment research by using remote sensing, summed up some representative models and methods, and analyzes the deficiencies of existing methods. Combined with the recent progress of remote sensing theory and application in water suspended sediment research, we introduced in some data processing methods such as atmospheric correction method, adjacent effect correction, and some intelligence algorithms such as neural networks, genetic algorithms, support vector machines into the suspended sediment inversion research, combined with other geographic information, based on Bayesian theory, we improved the suspended sediment inversion precision, and aim to give references to the related researchers.

  7. Classification and Prediction of Event-based Suspended Sediment Dynamics using Artificial Neural Networks (United States)

    Hamshaw, S. D.; Underwood, K.; Wemple, B. C.; Rizzo, D.


    Sediment transport can be an immensely complex process, yet plays a vital role in the transport of substances and nutrients that can impact receiving waters. Advancements in the use of sensors for indirect measurement of suspended sediments have allowed access to high frequency sediment data. This has promoted the use of more advanced computational tools to identify patterns in sediment data to improve our understanding of physical processes occurring in the watershed. In this study, a network of weather stations and in-stream turbidity sensors were deployed to capture more than three years of sediment dynamics and meteorological data in the Mad River watershed in central Vermont. Monitoring sites were located along the main stem of the the Mad River and on five tributaries. Separate storm events were identified from the data at each site to study event sediment dynamics associated with erosion and deposition over space and time. Two types of artificial neural networks (ANNs), a self-organizing map (SOM) and a radial basis function (RBF), were used to cluster the storm event data based on hydrometeorological metrics and were subsequently compared to traditional classes of hysteresis patterns in suspended sediment concentration - discharge (SSC-Q) relationships. Hysteresis patterns were also directly used as inputs to both ANNs to identify distinct patterns and test the applicability of performing pattern recognition on hysteresis patterns. The results of this study will be used to gain insight into the dynamic physical processes (both spatial and temporal) occurring in the watershed based on patterns observed in SSQ-Q data.

  8. Documentation of particle-size analyzer time series, and discrete suspended-sediment and bed-sediment sample data collection, Niobrara River near Spencer, Nebraska, October 2014 (United States)

    Schaepe, Nathaniel J.; Coleman, Anthony M.; Zelt, Ronald B.


    The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers, monitored a sediment release by Nebraska Public Power District from Spencer Dam located on the Niobrara River near Spencer, Nebraska, during the fall of 2014. The accumulated sediment behind Spencer Dam ordinarily is released semiannually; however, the spring 2014 release was postponed until the fall. Because of the postponement, the scheduled fall sediment release would consist of a larger volume of sediment. The larger than normal sediment release expected in fall 2014 provided an opportunity for the USGS and U.S. Army Corps of Engineers to improve the understanding of sediment transport during reservoir sediment releases. A primary objective was to collect continuous suspended-sediment data during the first days of the sediment release to document rapid changes in sediment concentrations. For this purpose, the USGS installed a laser-diffraction particle-size analyzer at a site near the outflow of the dam to collect continuous suspended-sediment data. The laser-diffraction particle-size analyzer measured volumetric particle concentration and particle-size distribution from October 1 to 2 (pre-sediment release) and October 5 to 9 (during sediment release). Additionally, the USGS manually collected discrete suspended-sediment and bed-sediment samples before, during, and after the sediment release. Samples were collected at two sites upstream from Spencer Dam and at three bridges downstream from Spencer Dam. The resulting datasets and basic metadata associated with the datasets were published as a data release; this report provides additional documentation about the data collection methods and the quality of the data.

  9. Mucous Secretion and Cilia Beating Defend Developing Coral Larvae from Suspended Sediments.

    Directory of Open Access Journals (Sweden)

    Gerard F Ricardo

    Full Text Available Suspended sediments produced from dredging activities, or added to the sediment budget via river runoff, are a concern for marine resource managers. Understanding the impact of suspended sediments on critical life history stages of keystone species like corals is fundamental to effective management of coastlines and reefs. Coral embryos (Acropora tenuis and A. millepora and larvae (A. tenuis, A. millepora and Pocillopora acuta were subjected to a range of suspended sediment concentrations of different sediment types (siliciclastic and carbonate to assess concentration-response relationships on ecologically relevant endpoints, including survivorship and ability to metamorphose. Embryos were subjected to short (12 h suspended sediment exposures from ages of 3-12 hours old or a long (30 h exposure at 6 hours old. Neither the survivorship nor metamorphosis function of embryos were significantly affected by realistic sediment exposures to ~1000 mg L-1. However, some embryos exhibited a previously undescribed response to dynamically suspended sediments, which saw 10% of the embryos form negatively buoyant cocoons at siliciclastic suspended sediment concentrations ≥35 mg L-1. Scanning electron and optical microscopy confirmed the presence of a coating on these embryos, possibly mucus with incorporated sediment particles. Cocoon formation was common in embryos but not in larvae, and occurred more often after exposure to siliciclastic rather than carbonate sediments. Once transferred into sediment-free seawater, functional ~36-h-old embryos began emerging from the cocoons, coinciding with cilia development. Ciliated (> 36-h-old larvae exposed to suspended sediments for 60 h were also observed to secrete mucus and were similarly unaffected by suspended sediment concentrations to ~800 mg L-1. This study provides evidence that mucous secretion and cilia beating effectively protect coral embryos and larvae from suspended sediment and that these mechanisms

  10. Hysteresis in suspended sediment to turbidity relations due to changing particle size distributions (United States)

    Landers, Mark N.; Sturm, Terry W.


    Turbidity (T) is the most ubiquitous of surrogate technologies used to estimate suspended-sediment concentration (SSC). The effects of sediment size on turbidity are well documented; however, effects from changes in particle size distributions (PSD) are rarely evaluated. Hysteresis in relations of SSC-to-turbidity (SSC~T) for single stormflow events was observed and quantified for a data set of 195 concurrent measurements of SSC, turbidity, discharge, velocity, and volumetric PSD collected during five stormflows in 2009–2010 on Yellow River at Gees Mill Road in metropolitan Atlanta, Georgia. Regressions of SSC-normalized turbidity (T/SSC) on concurrently measured PSD percentiles show an inverse, exponential influence of particle size on turbidity that is not constant across the size range of the PSD. The majority of the influence of PSD on T/SSC is from particles of fine-silt and smaller sizes (finer than 16 microns). This study shows that small changes in the often assumed stability of the PSD are significant to SSC~T relations. Changes of only 5 microns in the fine silt and smaller size fractions of suspended sediment PSD can produce hysteresis in the SSC~T rating that can increase error and produce bias. Observed SSC~T hysteresis may be an indicator of changes in sediment properties during stormflows and of potential changes in sediment sources. Trends in the PSD time series indicate that sediment transport is capacity-limited for sand-sized sediment in the channel and supply-limited for fine silt and smaller sediment from the hillslope.

  11. Suspended sediment dynamics in Cochin estuary, West coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Vinita, J.; Revichandran, C.; Manoj, N.T.

    was the main contributing process for residual fluxes during the dry-spring period. The residual sediment transport at the inlet was directed outward irrespective of tidal ranges and seasons due to the strong ebb currents with longer duration. These findings...

  12. An at-grade stabilization structure impact on runoff and suspended sediment (United States)

    Minks, Kyle R.; Lowery, Birl; Madison, Fred W.; Ruark, Matthew; Frame, Dennis R.; Stuntebeck, Todd D.; Komiskey, Matthew J.


    In recent years, agricultural runoff has received more attention as a major contributor to surface water pollution. This is especially true for the unglaciated area of Wisconsin, given this area's steep topography, which makes it highly susceptible to runoff and soil loss. We evaluated the ability of an at-grade stabilization structure (AGSS), designed as a conservation practice to reduce the amount of overland runoff and suspended sediment transported to the surface waters of an agricultural watershed. Eight years of storm and baseflow data collected by the US Geological Survey–Wisconsin Water Science Center on a farm in west central Wisconsin were analyzed for changes in precipitation, storm runoff volume, and suspended sediment concentration before and after installation of an AGSS. The agricultural research site was designed as a paired watershed study in which monitoring stations were installed on the perennial streams draining both control and treatment watersheds. Linear mixed effects model analyses were conducted to determine if any statistically significant changes occurred in the water quality parameters before and after the AGSS was installed. Results indicated no significant changes (p = 0.51) in average event precipitation and runoff volumes before and after installation of the AGSS in either the treatment (NW) or control (SW) watersheds. However, the AGSS did significantly reduce the average suspended sediment concentration in the event runoff water (p = 0.02) in the NW from 972 to 263 mg L–1. In addition, particle size analyses, using light diffraction techniques, were conducted on soil samples taken from within the AGSS and adjacent valley and ridge top to determine if suspended sediments were being retained within the structure. Statistical analysis revealed a significantly (p < 0.001) larger proportion of clay inside the AGSS (37%) than outside (30%). These results indicate that the AGSS was successful in reducing the amount of suspended

  13. Rainfall, runoff and sediment transport in a Mediterranean mountainous catchment. (United States)

    Tuset, J; Vericat, D; Batalla, R J


    The relation between rainfall, runoff, erosion and sediment transport is highly variable in Mediterranean catchments. Their relation can be modified by land use changes and climate oscillations that, ultimately, will control water and sediment yields. This paper analyses rainfall, runoff and sediment transport relations in a meso-scale Mediterranean mountain catchment, the Ribera Salada (NE Iberian Peninsula). A total of 73 floods recorded between November 2005 and November 2008 at the Inglabaga Sediment Transport Station (114.5 km(2)) have been analysed. Suspended sediment transport and flow discharge were measured continuously. Rainfall data was obtained by means of direct rain gauges and daily rainfall reconstructions from radar information. Results indicate that the annual sediment yield (2.3 t km(-1) y(-1) on average) and the flood-based runoff coefficients (4.1% on average) are low. The Ribera Salada presents a low geomorphological and hydrological activity compared with other Mediterranean mountain catchments. Pearson correlations between rainfall, runoff and sediment transport variables were obtained. The hydrological response of the catchment is controlled by the base flows. The magnitude of suspended sediment concentrations is largely correlated with flood magnitude, while sediment load is correlated with the amount of direct runoff. Multivariate analysis shows that total suspended load can be predicted by integrating rainfall and runoff variables. The total direct runoff is the variable with more weight in the equation. Finally, three main hydro-sedimentary phases within the hydrological year are defined in this catchment: (a) Winter, where the catchment produces only water and very little sediment; (b) Spring, where the majority of water and sediment is produced; and (c) Summer-Autumn, when little runoff is produced but significant amount of sediments is exported out of the catchment. Results show as land use and climate change may have an important

  14. State-shifting at the edge of resilience: River suspended sediment responses to land use change and extreme storms (United States)

    Abbott, Samantha; Julian, Jason P.; Kamarinas, Ioannis; Meitzen, Kimberly M.; Fuller, Ian C.; McColl, Samuel T.; Dymond, John R.


    The interaction of climate, geomorphology, and land use dictates catchment sediment production and associated river sediment loads. Accordingly, the resilience of catchments to disturbances can be assessed with suspended sediment regimes. This case study in the hill country of the lower North Island of New Zealand was a decade-long examination of the short- and long-term effects of an extreme storm event on sediment supply and exhaustion in the Oroua and Pohangina catchments, two catchments that have experienced intense land use changes and frequent broad-scale landslides. Indicators of Hydrologic Alteration, a program developed to characterize hydrologic regimes, was used to analyze daily suspended sediment records over a period of a decade in order to characterize sediment regimes of the Oroua and Pohangina. An aggregated data set of sediment-bearing events for the period of record was analyzed to examine the suspended sediment response of individual storms relative to runoff magnitudes. The findings of this study demonstrate that large storms that generate extreme landsliding and flooding have the ability to produce enough sediment to temporarily convert catchments from a supply-limited state to a transport-limited state. Landsliding and thus sediment supply was disproportionately high in locations where livestock grazing occurred on steep hillslopes. The timing and intensity of previous storms, or the antecedent catchment condition, was also shown to influence the response of the catchments. In both catchments, suspended sediment loads were elevated for a period of 4 years following the landslide-generating February 2004 storm. The methods and findings we present are useful for assessing the resilience of catchments exposed to frequent disturbances such as land use changes and landslides.

  15. Suspended sediment behavior in a coastal dry-summer subtropical catchment: Effects of hydrologic preconditions (United States)

    Variation in fluvial suspended sediment–discharge behavior is generally thought to be the product of changes in processes governing the delivery of sediment and water to the channel. The objective of this study was to infer sediment supply dynamics from the response of suspended ...

  16. Satellite estimates of wide-range suspended sediment concentrations in Changjiang (Yangtze) estuary using MERIS data

    NARCIS (Netherlands)

    Shen, F.; Verhoef, W.; Zhou, Y.; Salama, M.S.; Liu, X.


    The Changjiang (Yangtze) estuarine and coastal waters are characterized by suspended sediments over a wide range of concentrations from 20 to 2,500 mg l-1. Suspended sediment plays important roles in the estuarine and coastal system and environment. Previous algorithms for satellite estimates of

  17. Sediment budget and interannual variations of suspended sediment load in the Rio Cordon (Italy). Three decades of monitoring and investigations (1987-2014). (United States)

    García-Rama, Adriana; Rainato, Riccardo; Mao, Luca; Picco, Lorenzo; Aristide Lenzi, Mario


    This work shows the results of 28 years of measurements carried out in the Rio Cordon catchment, an Alpine watershed where a measuring station continuously recorded water discharge, bedload and suspended sediment transport since 1987. Hourly values of discharge and suspended sediment transport (or 5 min interval during flood events) have been studied throughout the whole study period. Annual and seasonal variations of suspended sediment load during the study period were analyzed along with their contribution to the total sediment yield. Comparing these almost three decades, the highest suspended solid transport occurred in 1994, 2001, 1987, 1998, 2002 and 2009, during which it was 2521.5, 1568.5, 792, 745, 551 and 514.8 t year-1, respectively. Summer and autumn contributions were significant in 1989, 1994, 1996, 1998, 2002, and 2005; on the other hand 2001 was characterized by a snowmelt flood that generated almost all the suspended load. A notable variability of the suspended solid transport can be observed taking in count snowmelt floods. Also 1987, 2001, 2008, 2009 and 2010 are characterized by a very important role of this kind of runoff. Data collected in the Rio Cordon for 28 years show that 75.2% of the total sediment load (10597.8 t of 14088.8 t) was due to suspended sediment transport. In 1994 and 2001, a large portion of the suspended sediment load was mainly supplied during the flood events that occurred in September 1994 and May 2001, which produced 198 and 1017.5 t respectively. Averaging 28 years of data, the mean annual specific sediment yield turns out to be around 102,9 t km-2 year-1. However, this value includes the 1986-1993 period characterized by ordinary flood events during which de mean sediment production was 65.34 t km-2 year-1, the massive sediment yield in 1994 (803.4 t km-2 year-1), the 1995-2000 period (93.2 t km-2 year-1), the 2001 (343.8 km-2 year-1) and the 2002-2014 period(54.5 t km-2 year-1). The highest values correspond to 1994

  18. Sediment Size Effects in Acoustic Doppler Velocimeter-Derived Estimates of Suspended Sediment Concentration

    Directory of Open Access Journals (Sweden)

    Mehmet Öztürk


    Full Text Available Backscatter output from a 10 MHz acoustic Doppler velocimeter (ADV was used to quantify suspended sediment concentrations in a laboratory setting using sand-sized particles. The experiments included (a well-sorted sand samples ranging in size from 0.112 to 0.420 mm, obtained by the sieving of construction sand, (b different, known mixtures of these well-sorted fractions, and (c sieved natural beach sand with median sizes ranging from 0.112 to 0.325 mm. The tested concentrations ranged from 25 to 3000 mg•L−1. The backscatter output was empirically related to concentration and sediment size, and when non-dimensionalized by acoustic wavelength, a dimensionless sediment size gradation coefficient. Size-dependent upper and lower bounds on measurable concentrations were also established empirically. The range of measurable conditions is broad enough to make the approach useful for sand sizes and concentrations commonly encountered in nature. A new method is proposed to determine concentrations in cases of mixed-size sediment suspensions when only calibration data for well-sorted constituent sands are available. This approach could potentially allow better estimates when the suspended load is derived from but is not fully representative of the bed material, and when the size characteristics of the suspended material are varying in time over the period of interest. Differences in results between the construction and beach sands suggest that sediment shape may also need to be considered, and point to the importance of calibrating to sediments encountered at the site of interest.

  19. Contemporary suspended sediment dynamics within two partly glacierized mountain drainage basins in western Norway (Erdalen and Bødalen, inner Nordfjord) (United States)

    Beylich, Achim A.; Laute, Katja; Storms, Joep E. A.


    This paper focuses on environmental controls, spatiotemporal variability and rates of contemporary fluvial suspended sediment transport in the neighboring, partly glacierized and steep Erdalen (79.5 km2) and Bødalen (60.1 km2) drainage basins in the fjord landscape of the inner Nordfjord in western Norway. Field work, including extended samplings and measurements, was conducted since 2004 in Erdalen and since 2008 in Bødalen. The distinct intra- and inter-annual temporal variability of suspended sediment transport found is mostly controlled by meteorological events, with most suspended sediment transport occurring during pluvial events in autumn (September-November), followed by mostly thermally determined glacier melt in summer (July-August), and by mostly thermally determined snowmelt in spring (April-June). Extreme rainfall events (> 70 mm d- 1) in autumn can trigger significant debris-flow activity that can cause significant transfers of suspended sediments from ice-free surface areas with sedimentary covers into main stream channels and is particularly important for fluvial suspended sediment transport. In years with occurring relevant debris-flow activity the total annual drainage-basin wide suspended sediment yields are strongly determined by these single extreme events. The proportion of glacier coverage, followed by steepness of slopes, and degree of vegetation cover in ice-free surface areas with sedimentary covers are the main controls for the detected spatial variability of suspended sediment yields. The contemporary sediment supply from glacierized surface areas and the Jostedalsbreen ice cap through different defined outlet glaciers shows a high spatial variability. The fact that the mean annual suspended sediment yield of Bødalen is with 31.3 t km- 2 yr- 1 almost twice as high as the mean annual suspended sediment yield of Erdalen (16.4 t km- 2 yr- 1) is to a large extent explained by the higher proportion of glacier coverage in Bødalen (38% of

  20. Anthropogenic Impact on Sediment Transport in the Mississippi River (United States)

    Gregory, Brittney; Herrmann, Achim; Clift, Peter


    Many of the most prominent deltas in the world are suffering from sediment starvation and subsidence due to human alteration of the upper catchments. The Mississippi River Delta is not immune to these problems which are accentuated by the addition of dams and artificial levees diverting sediment from the delta and coast throughout the last century. The Missouri, Ohio, and Arkansas Rivers have historically supplied most of the suspended sediment load to the Lower Mississippi over the last 60 years, with the Missouri being the largest single contributor. While suspended sediment load plays an important role in floodplain and delta construction, the transport of coarser sediment is also important to a healthy coastline. Very little data exists to constrain how coarser sediment is mixed and transported down the Mississippi despite its invaluable importance to the coastal beaches and barrier islands. Using traditional provenance tools it is possible to study both the coarse and fine load of the modern Mississippi River to quantify transportation and mixing models. This, in turn, will demonstrate human impact on both the suspended and bedload of the Mississippi and its tributaries. This study uses apatite rare earth element geochemistry and zircon U-Pb dating in conjunction with Sr-Nd isotope ratios and clay mineralogy to interpret the transportation of both fine and coarse sediment within the modern Mississippi and its tributaries. These data are preliminary and are part of a larger study that will determine anthropogenic impact on the aggradation of the modern delta floodplain over the last 1000 years.

  1. Vertical transport of suspended particulate trace elements in the North Atlantic Ocean

    International Nuclear Information System (INIS)

    Kuss, J.; Kremling, K.; Scholten, J.


    Suspended marine particles play a key role in the exchange processes between rapidly sinking particles and seawater because of their large surface area and long residence times. They are involved in the transport processes of rapidly sinking particles (∼ 100 m/day) through aggregation and disaggregation. This mechanism results in a net downward transport of suspended particulate trace elements (TE). To provide more information to these processes TE in suspended particulate material (SPM) have been measured on three cruises from 1995 to 1997 along 20 deg. W using a large volume in situ filtration between 25 m and 4150 m depth in addition to particle flux measurements with sediment traps. These studies were performed under the framework of German JGOFS

  2. Fluvial sediments a summary of source, transportation, deposition, and measurement of sediment discharge (United States)

    Colby, B.R.


    This paper presents a broad but undetailed picture of fluvial sediments in streams, reservoirs, and lakes and includes a discussion of the processes involved in the movement of sediment by flowing water. Sediment is fragmental material that originates from the chemical or physical disintegration of rocks. The disintegration products may have many different shapes and may range in size from large boulders to colloidal particles. In general, they retain about the same mineral composition as the parent rocks. Rock fragments become fluvial sediment when they are entrained in a stream of water. The entrainment may occur as sheet erosion from land surfaces, particularly for the fine particles, or as channel erosion after the surface runoff has accumulated in streams. Fluvial sediments move in streams as bedload (particles moving within a few particle diameters of the streambed) or as suspended sediment in the turbulent flow. The discharge of bedload varies with several factors, which may include particle size and a type of effective shear on the surface of the streambed. The discharge of suspended sediment depends partly on concentration of moving sediment near the streambed and hence on discharge of bedload. However, the concentration of fine sediment near the streambed varies widely, even for equal flows, and, therefore, the discharge of fine sediment normally cannot be computed theoretically. The discharge of suspended sediment also depends on velocity, turbulence, depth of flow, and fall velocity of the particles. In general, the coarse sediment transported by a stream moves intermittently and is discharged at a rate that depends on properties of the flow and of the sediment. If an ample supply of coarse sediment is available at the surface of the streambed, the discharge of the coarse sediment, such as sand, can be roughly computed from properties of the available sediment and of the flow. On the other hand, much of the fine sediment in a stream usually moves nearly

  3. A Coupled Model of the 1D River Network and 3D Estuary Based on Hydrodynamics and Suspended Sediment Simulation

    Directory of Open Access Journals (Sweden)

    Wei Zhang


    Full Text Available River networks and estuaries are very common in coastal areas. Runoff from the upper stream interacts with tidal current from open sea in these two systems, leading to a complex hydrodynamics process. Therefore, it is necessary to consider the two systems as a whole to study the flow and suspended sediment transport. Firstly, a 1D model is established in the Pearl River network and a 3D model is applied in its estuary. As sufficient mass exchanges between the river network and its estuary, a strict mathematical relationship of water level at the interfaces can be adopted to couple the 1D model with the 3D model. By doing so, the coupled model does not need to have common nested grids. The river network exchanges the suspended sediment with its estuary by adding the continuity conditions at the interfaces. The coupled model is, respectively, calibrated in the dry season and the wet season. The results demonstrate that the coupled model works excellently in simulating water level and discharge. Although there are more errors in simulating suspended sediment concentration due to some reasons, the coupled model is still good enough to evaluate the suspended sediment transport in river network and estuary systems.

  4. How are macroinvertebrates of slow flowing lotic systems directly affected by suspended and deposited sediments?

    Energy Technology Data Exchange (ETDEWEB)

    Kefford, Ben J., E-mail: [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Zalizniak, Liliana [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Dunlop, Jason E. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia); Smart Water Research Facility, Griffith University, Queensland (Australia); Nugegoda, Dayanthi [Biotechnology and Environmental Biology, School of Applied Sciences, RMIT University, PO Box 71, Bundoora, Victoria 3083 (Australia); Choy, Satish C. [Department of Environment and Resource Management (DERM), 120 Meiers Rd, Indooroopilly, Queensland 4068 (Australia)


    The effects of suspended and deposited sediments on the macroinvertebrates are well documented in upland streams but not in slower flowing lowland rivers. Using species found in lowland lotic environments, we experimentally evaluate mechanisms for sediments to affect macroinvertebrates, and in one experiment whether salinity alters the effect of suspended sediments. Suspended kaolin clay reduced feeding of Ischnura heterosticta (Odonata: Coenagrionidae) at high turbidity (1000-1500 NTU) but had no effects on feeding of Hemianax papuensis (Odonata: Aeshnidae) and Micronecta australiensis (Hemiptera: Corixidae). In freshwater (0.1 mS/cm), survival of Ischnura aurora was poor in clear water, but improved with suspended kaolin. Growth and feeding of I. aurora were unaffected by suspended sediments and salinity. Burial (1-5 mm) of eggs with kaolin or sand reduced hatching in Physa acuta (Gastropoda: Physidae), Gyraulus tasmanica (Gastropoda: Planorbidae) and Chironomus cloacalis (Diptera: Chironomidae). Settling sediments may pose greater risk to lowland lotic invertebrates than suspended sediments. - Sediment deposition may be more directly detrimental to macroinvertebrates of lowland rivers than suspended sediments.

  5. Aerial Photo Utilization in Estimating Suspended Sediment in the Wuryantoro Watershed, Wonogiri

    Directory of Open Access Journals (Sweden)

    Sugiharto Budi Santoso


    Full Text Available Suspended sediment load flowing out from a watershed is normally predicated by analysis os suspended sediment of water sample, and the volume of suspended sediment be calculated based on sediment concentration and river discharge. Such field measurements need a lot of field data and they are time consuming. Another method for prediction of suspended sediment by using remote sensing imagery data and recorded rainfall data. The objective of this research is to 1 examine the capability of remote sensing technique to obtain the parameters of the physical data of land in the prediction of suspended sediment; 2 examine the accuracy of the model for prediction suspended sediment. This research is carried out in Wuryantoro watershed, Wonogiri. The main data to obtain the parameters of the physical data of land is infrared aerial photograph on scale 1 : 10.000. the method that used in this research is interpretation of remote sensing imagery data, combined with rainfall data. The result show that the accuracy of landuse is 88.5%, the accuracy of slope is 87.67%. the accuracy of the prediction of suspended sediment by model A3 87.07%, model C1 86.63%, model C2 90.57%, model A8 84.13%, model A9 80.1%, and model C4 78.6%.

  6. Increase in suspended sediment discharge of the Amazon River assessed by monitoring network and satellite data


    Martinez, Jean-Michel; Guyot, Jean-Loup; Filizola, N.; Sondag, Francis


    This study addresses the quantification of the Amazon River sediment budget which has been assessed by looking at data from a suspended sediment discharge monitoring network and remote sensing estimates derived from MODIS spaceborne sensor. Surface suspended sediment concentration has been sampled every 10 days since 1995 (390 samples available) by the international HYBAM program at the Obidos station which happens to be the last gauged station of the Amazon River before the Atlantic Ocean. R...

  7. Effect of suspended-sediment concentration on nitrification in river water: importance of suspended sediment-water interface. (United States)

    Xia, Xinghui; Yang, Zhifeng; Zhang, Xueqing


    High suspended sediment (SPS) concentrations exist in many Asian river systems. In this research, the effects of SPS concentration on nitrification in river water systems were studied. With orwithout introducing ammonium-oxidizing bacteria isolated from the water and sediment samples of the Yellow River, the microbially mediated nitrification rate increased with SPS concentration as described by the power function y = a x x(b), where y is the nitrification rate, x is the SPS concentration, and a and b are constants. With an indigenous ammonium-oxidizing bacteria, nitrification rate constants, i.e., K4 (micromax/Ks) values obtained from the Monod model, were 0.0016, 0.0036, 0.0040, 0.0063, 0.0066, 0.0071, and 0.0077 day(-1) microM(-1) for the systems with SPS concentrations of 0, 0.2 1.0, 5.0, 10, 20, and 40 g/L, respectively. The sorption percentage of NH4+-N increased with SPS concentration as a power function. Bacteria tend to attach onto SPS, and the maximum specific growth rate at the SPS-water interface was about twice that in the water phase. An increase of bacterial population and nitrification rate constant with SPS as a power function resulted in an increase of nitrification rate with SPS as a power function. Therefore, the high SPS concentration caused by erosion and bottom sediment resuspension and other factors will accelerate ammonium oxidation in many turbid river systems. This has useful implications for nitrogen removal from river systems.

  8. Characterization of Suspended-Sediment Loading to and from John Redmond Reservoir, East-Central Kansas, 2007-2008 (United States)

    Lee, Casey J.; Rasmussen, Patrick P.; Ziegler, Andrew C.


    Storage capacity in John Redmond Reservoir is being lost to sedimentation more rapidly than in other federal impoundments in Kansas. The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, initiated a study to characterize suspended-sediment loading to and from John Redmond Reservoir from February 21, 2007, through February 21, 2008. Turbidity sensors were installed at two U.S. Geological Survey stream gages upstream (Neosho River near Americus and the Cottonwood River near Plymouth) and one stream gage downstream (Neosho River at Burlington) from the reservoir to compute continuous, real-time (15-minute) measurements of suspended-sediment concentration and loading. About 1,120,000 tons of suspended-sediment were transported to, and 100,700 tons were transported from John Redmond Reservoir during the study period. Dependent on the bulk density of sediment stored in the reservoir, 5.0 to 1.4 percent of the storage in the John Redmond conservation pool was lost during the study period, with an average deposition of 3.4 to 1.0 inches. Nearly all (98-99 percent) of the incoming sediment load was transported during 9 storms which occurred 25 to 27 percent of the time. The largest storm during the study period (peak-flow recurrence interval of about 4.6-4.9 years) transported about 37 percent of the sediment load to the reservoir. Suspended-sediment yield from the unregulated drainage area upstream from the Neosho River near Americus was 530 tons per square mile, compared to 400 tons per square mile upstream from the Cottonwood River near Plymouth. Comparison of historical (1964-78) to current (2007) sediment loading estimates indicate statistically insignificant (99 percent) decrease in sediment loading at the Neosho River at Burlington. Ninety-percent confidence intervals of streamflow-derived estimates of total sediment load were 7 to 21 times larger than turbidity-derived estimates. Results from this study can be used by natural resource

  9. Characteristics of suspended sediment and river discharge during the beginning of snowmelt in volcanically active mountainous environments (United States)

    Mouri, Goro; Ros, Faizah Che; Chalov, Sergey


    To better understand instream suspended sediment delivery and transformation processes, we conducted field measurements and laboratory experiments to study the natural function of spatial and temporal variation, sediment particles, stable isotopes, particle size, and aspect ratio from tributary to mainstream flows of the Sukhaya Elizovskaya River catchment at the beginning of and during snowmelt. The Sukhaya Elizovskaya River is located in the Kamchatka Peninsula of Russia and is surrounded by active volcanic territory. The study area has a range of hydrological features that determine the extreme amounts of washed sediments. Sediment transported to the river channels in volcanic mountainous terrain is believed to be strongly influenced by climate conditions, particularly when heavy precipitation and warmer climate trigger mudflows in association with the melting snow. The high porosity of the channel bottom material also leads to interactions with the surface water, causing temporal variability in the daily fluctuations in water and sediment flow. Field measurements revealed that suspended sediment behaviour and fluxes decreased along the mainstream Sukhaya Elizovskaya River from inflows from a tributary catchment located in the volcanic mountain range. In laboratory experiments, water samples collected from tributaries were mixed with those from the mainstream flow of the Sukhaya Elizovskaya River to examine the cause of debris flow and characteristics of suspended sediment in the mainstream. These findings and the geological conditions of the tributary catchments studied led us to conclude that halloysite minerals likely comprise the majority of suspended sediments and play a significant role in phosphate adsorption. The experimental results were upscaled and verified using field measurements. Our results indicate that the characteristics of suspended sediment and river discharge in the Sukhaya Elizovskaya River can be attributed primarily to the beginning of

  10. Evaluation of suspended sediment concentrations, sediment fluxes and sediment depositions along a reservoir by using laser diffraction and acoustic backscatter data (United States)

    Lizano, Laura; Haun, Stefan


    The construction of dams and reservoirs disturb the natural morphological behavior of rivers. A natural settling effect occurs due to the reduced turbulences and flow velocities. As a consequence, reservoirs fill up with sediments which results in a reduction of storage volume, influences the operation of hydropower plants and leads in several cases to flood protection problems. The sediment depositions in reservoirs are standardly evaluated by using bathymetric data, obtained by a single beam sonar from pre-defined cross sections or by an extensive evaluation of the reservoir bed by a side scan sonar. However, a disadvantage of this method is that it is not possible to evaluate the pore water content of the depositions, which may lead as consequence to an uncertainty in the measured amount of deposited sediments. Given that a major part of sediments entering reservoirs are transported in suspension, sediment flux measurements along defined transects could give more reliable information on the settled amount of sediments and additional information on the sediment transport mechanism within the reservoir. An evaluation of the sediment fluxes is in practice often conducted by a single suspended sediment concentration (SSC) measurement in combination with a cross sectional calibration factor to take changes in the SSC along the transect into account. However, these calibration factors are often developed only for one specific in-situ condition and may give unreliable results in case that the boundaries change e.g. the hydraulic conditions. Hence an evaluation of the sediment fluxes along the whole transect would give a more reliable number for the amount of transported sediments through the reservoir. This information can afterwards be used to calculate the amount of settled sediments in different sections of the reservoir and the amount of sediments which will enter the intake. For this study the suspended sediment transport within the Peñas Blancas reservoir in

  11. Modelling spatial and temporal variations of annual suspended sediment yields from small agricultural catchments. (United States)

    Rymszewicz, A; Bruen, M; O'Sullivan, J J; Turner, J N; Lawler, D M; Harrington, J R; Conroy, E; Kelly-Quinn, M


    Estimates of sediment yield are important for ecological and geomorphological assessment of fluvial systems and for assessment of soil erosion within a catchment. Many regulatory frameworks, such as the Convention for the Protection of the Marine Environment of the North-East Atlantic, derived from the Oslo and Paris Commissions (OSPAR) require reporting of annual sediment fluxes. While they may be measured in large rivers, sediment flux is rarely measured in smaller rivers. Measurements of sediment transport at a national scale can be also challenging and therefore, sediment yield models are often utilised by water resource managers for the predictions of sediment yields in the ungauged catchments. Regression based models, calibrated to field measurements, can offer an advantage over complex and computational models due to their simplicity, easy access to input data and due to the additional insights into factors controlling sediment export in the study sites. While traditionally calibrated to long-term average values of sediment yields such predictions cannot represent temporal variations. This study addresses this issue in a novel way by taking account of the variation from year to year in hydrological variables in the developed models (using annual mean runoff, annual mean flow, flows exceeded in five percentage of the time (Q5) and seasonal rainfall estimated separately for each year of observations). Other parameters included in the models represent spatial differences influenced by factors such as soil properties (% poorly drained soils and % peaty soils), land-use (% pasture or % arable lands), channel slope (S1085) and drainage network properties (drainage density). Catchment descriptors together with year-specific hydrological variables can explain both spatial differences and inter-annual variability of suspended sediment yields. The methodology is demonstrated by deriving equations from Irish data-sets (compiled in this study) with the best model

  12. Acoustic Measurement of Suspended Sediment Flux Over Ripples and Dunes in Unidirectional Flow (United States)

    Wilson, G.; Hay, A. E.; Zedel, L. J.


    In May 2015, an experiment was conducted in the main channel flume at the St. Anthony Falls Laboratory, to measure suspended- and bed-load sediment transport using a multi-frequency acoustic Doppler instrument (MFDop). The flume was operated with 1 meter water depth over a 50 cm thick bed of naturally-sourced medium sand. The flume uses water diverted from the Mississippi River. Therefore, the experiment closely simulated realistic field conditions, including high flow rates, turbid water, and sediment grain size variability. A series of experiments was conducted at different flow rates, ranging from the threshold of sediment transport ( 1000 L/s) up to a regime with 2 meter wavelength sand ripples ( 2000 L/s). At each flow rate, the MFDop was used to measure profiles of multi-frequency acoustic backscatter and 3-component velocity, from bed level to 10's of cm above-bed, in 4 mm range bins and at 30 Hz sampling rate. A rotary sonar was used to monitor the migration of bedforms under the MFDop during the data collection, until a full ripple phase had been observed. These data are used to quantify the statistics of time-resolved near-bed sediment suspension and flux at different ripple phases, via inversion of a model for multi-frequency acoustic backscatter amplitude as a function of grain size and concentration.

  13. Trend of suspended sediment load in the Velika Morava River in the period 1967-2007

    Directory of Open Access Journals (Sweden)

    Mustafić Sanja


    Full Text Available The paper is concerned with identifying changes in the time series of discharge (Q, suspended sediment concentration (SSC and sediment load (Qs of the Velika Morva River. The catchment area on farthest hydrological profile Ljubičevski most on Velika Morava River is approximately 35,496 km2. In this profile were carried out daily measurements of flow and concetration of silt in the period from 1967 to 2007. Average perennial transport of suspended sediment is 2.57ˣ106 t (72.4 t/km2/yr and ranged from 0.17ˣ106 t (4.8 t/km2/yr to 10.02ˣ106 t (282.2 t/km2/yr. Trends determined for Q, SSC and Qs are statistically obtained using the non-parametric Mann-Kendall test. Results of Mann-Kendall test show that Q has a slight declining trend of annual values which do not show statistical significance. Decline in trendline SSC and Qs is a significant at the level of 0.01. Calculating the standardized regression coefficients, it was found that the relative impact of SSC on sediment load is 3.1 time higher than the impact of discharge. From 1967 to 2007 the average decrease in sediment load at the mouth of the Velika Morava into the Danube was 3.1 t/km2/yr. [Projekat Ministarstva nauke Republike Srbije, br. 43007: The Research on Climate Change Influences on Environment: Influence Monitoring, Adaptation and Mitigation, subproject No. 9: Torrential Floods Frequency, Soil and Water Degradation as the Consequence of Global Changes

  14. Continuous-flow centrifugation to collect suspended sediment for chemical analysis (United States)

    Conn, Kathleen E.; Dinicola, Richard S.; Black, Robert W.; Cox, Stephen E.; Sheibley, Richard W.; Foreman, James R.; Senter, Craig A.; Peterson, Norman T.


    Recent advances in suspended-sediment monitoring tools and surrogate technologies have greatly improved the ability to quantify suspended-sediment concentrations and to estimate daily, seasonal, and annual suspended-sediment fluxes from rivers to coastal waters. However, little is known about the chemical composition of suspended sediment, and how it may vary spatially between water bodies and temporally within a single system owing to climate, seasonality, land use, and other natural and anthropogenic drivers. Many water-quality contaminants, such as organic and inorganic chemicals, nutrients, and pathogens, preferentially partition in sediment rather than water. Suspended sediment-bound chemical concentrations may be undetected during analysis of unfiltered water samples, owing to small water sample volumes and analytical limitations. Quantification of suspended sediment‑bound chemical concentrations is needed to improve estimates of total chemical concentrations, chemical fluxes, and exposure levels of aquatic organisms and humans in receiving environments. Despite these needs, few studies or monitoring programs measure the chemical composition of suspended sediment, largely owing to the difficulty in consistently obtaining samples of sufficient quality and quantity for laboratory analysis.A field protocol is described here utilizing continuous‑flow centrifugation for the collection of suspended sediment for chemical analysis. The centrifuge used for development of this method is small, lightweight, and portable for the field applications described in this protocol. Project scoping considerations, deployment of equipment and system layout options, and results from various field and laboratory quality control experiments are described. The testing confirmed the applicability of the protocol for the determination of many inorganic and organic chemicals sorbed on suspended sediment, including metals, pesticides, polycyclic aromatic hydrocarbons, and

  15. Monitoring suspended sediments and turbidity in Sahelian basins (United States)

    Robert, Elodie; Grippa, Manuela; Kergoat, Laurent; Martinez, Jean-Michel; Pinet, Sylvain; Nogmana, Soumaguel


    Suspended matter can carry viruses and bacteria that are pathogenic to humans and can foster their development. Therefore, turbidity can be considered a vector of microbiological contaminants, which cause diarrheal diseases, and it can be used as a proxy for fecal bacteria. Few studies have focused on water turbidity in rural Africa, where many cases of intestinal parasitic infections are due to the consumption of unsafe water from ponds, reservoirs, lakes and rivers. Diarrheal diseases are indeed the second cause of infant mortality in sub-Saharan Africa. Furthermore, in this region, environment survey is minimal or inexistent. Monitoring water turbidity therefore represents a challenge for health improvement. Turbidity refers to the optical properties of water and it is well suited to monitoring by remote sensing. Because it varies in space and time and because the small water bodies (dry seasons however differ markedly, with a secondary maximum of SSSC in February occurring in 2016, possibly caused by wind-driven sediments remobilization or cattle trampling. The Niger River in Niamey displays a rapid increase in turbidity between mid-June and late August associated to the 'red' flood, with a maximum in late July-early August and then a sharp decline associated with the black flood. Overall, the high turbidity observed at these sites indicates clear risks for human health. The methods developed here for the AMMA-CATCH, RBV sites will be applied to all inland waters in West Africa.

  16. Total Suspended Load and Sediment Yield of Kayan River, Bulungan District, East Kalimantan

    Directory of Open Access Journals (Sweden)

    Suprapto Dibyosaputro


    Full Text Available This research was carried out the the drainage system of Kayan river, Bulungan District, East Kalimantan. The purpose of the research were to study the physical conditions of the Kayan catchment area, calculate the suspended sediment load, and to define the total sediment yield of Kayan River. Observation method were used in this research both of direct field observation as well as laboratory observation. Data acquired in this study were include of climatic data, geology, geomorphology, soil and land cover data. Besides also rain-fall data, temperature, river discharge and suspended sediment load. The total sediment yield were calculated by mean of mathematical and statistical analysis especially of linier regression analysis. The result of the research show that total the sediment yield of Kayan River with drainage area of 6,329.452 km² is about 236,921.25 m³/km²/year. The interesting result of the statistical analysis was that the existing negative correlation between river discharge and suspended sediment load. It is the effect of the location of discharge and suspended measurement. This condition caused by sea tide effect on river discharge at the apex delta. During high tide water river trend rising up on discharge but not on suspended sediment load. Instead, also existing setting down processes takes places of the suspended sediment load into the river bottom upper stream and the apex.

  17. Determination of the origin of suspended matter and sediments in the Elbe estuary using natural tracers

    International Nuclear Information System (INIS)

    Schoer, J.H.


    The clay mineral composition, the concentrations of carbonates, the proportions of carbon and oxygen isotopes in carbonates and organic matter, as well as the concentrations of different nonanthropogenic metals were used to determine the origin of different grain size fractions of sediments and suspended matter in the Elbe estuary. Analysis of the smectite/kaolinite proportion revealed that solid material · 2 μm from the North Sea is transported up the river, about 40 km beyond the most upstream position of the salt wedge. In the 2-20 μm fraction, the 16 O/ 18 O ratio in carbonates and the kaolinite/chlorite proportion demonstrate a transport of North Sea material between 40 and 20 km upstream of the marine water limit. The transport behavior of the 20-63 μm grain size fraction could be determined by the hafnium concentration, representative for the heavy mineral zircon. In this case, the transport distance beyond the salt wedge was up to 20 km. No information was available on the origin of the fine organic matter, whereas the coarser fractions were derived primarily from debris of salt marsh vegetation. The results demonstrate that in the Elbe estuary mixing between marine and fluvial solid material occurs upstream of the salt wedge and is significantly responsible for the observed decrease in the concentration of various pollutants in sediments and suspended matter along the estuary. The cause of the upstream particle transport is probably a scour lag mechanism based on asymmetries of the flood- and ebb-tide current distribution, especially their differing maximum velocities

  18. Effects of suspended culture of the seaweed Laminaria japonica aresch on the flow structure and sedimentation processes (United States)

    Zhang, Zehua; Huang, Haijun; Liu, Yanxia; Yan, Liwen; Bi, Haibo


    The culture of suspended kelp, such as Laminaria japonica Aresch, has arisen in nearshore areas for approximately 30 years since the 1980s. This long-term activity has significant impact on the regional hydrodynamic and sedimentary environments. In this study the impact was investigated, based on synchronized multi-station data from continuous observations made within and around the culture area. In total, three current velocity profiles were identified inside and on the landward side of the culture area. Based on the current velocity profiles we calculated the boundary layer parameters, the fluxes of erosion/deposition, and the rate of sediment transport in different times at each observation site. Comparison between culture and non-culture periods showed that the presence of suspended kelp caused the reduction in the average flow velocity by approximately 49.5%, the bottom friction velocity by 24.8%, the seabed roughness length by 62.7%, and the shear stress and the flux of resuspended sediment by approximately 50%. From analyses in combination with the corresponding vertical variation of the suspended sediment distribution, it is revealed that the lifted sediments by resuspension is mixed with the upper suspended material, which will modify the regional distribution of suspended sediment. These changes in flow structure and sediment movement will accelerate seabed siltation, which corresponds to the changes in seabed erosion/deposition. However, under the influences of the seasonal changes in kelp growth the magnitude of change with the seabed siltation was not obvious inside the culture area, but a fundamental change was apparent around the culture area.

  19. Chemical concentrations in water and suspended sediment, Green River to Lower Duwamish Waterway near Seattle, Washington, 2016–17 (United States)

    Conn, Kathleen E.; Black, Robert W.; Peterson, Norman T.; Senter, Craig A.; Chapman, Elena A.


    From August 2016 to March 2017, the U.S. Geological Survey (USGS) collected representative samples of filtered and unfiltered water and suspended sediment (including the colloidal fraction) at USGS streamgage 12113390 (Duwamish River at Golf Course, at Tukwila, Washington) during 13 periods of differing flow conditions. Samples were analyzed by Washington-State-accredited laboratories for a large suite of compounds, including metals, dioxins/furans, semivolatile compounds including polycyclic aromatic hydrocarbons, butyltins, the 209 polychlorinated biphenyl (PCB) congeners, and total and dissolved organic carbon. Concurrent with the chemistry sampling, water-quality field parameters were measured, and representative water samples were collected and analyzed for river suspended-sediment concentration and particle-size distribution. The results provide new data that can be used to estimate sediment and chemical loads transported by the Green River to the Lower Duwamish Waterway.

  20. Hydroclimatic influence on particle size distribution of suspended sediments evacuated from debris-covered Chorabari Glacier, upper Mandakini catchment, central Himalaya (United States)

    Kumar, Amit; Gokhale, Anupam Anand; Shukla, Tanuj; Dobhal, Dwarika Prasad


    Sediments released from high altitude glaciers exhibit varying evacuation patterns and transport characteristics owing to the presence of thick debris cover over the glacier. Despite the recent needs for integrated hydrometeorological studies in the Himalaya, little is known about the impacts of suspended sediment on hydropower generation, reservoir sedimentation, and abrasion of turbine components. Present study involves analysis of particle size distribution of suspended sediments to understand sediment evacuation patterns and transport characteristics in variable energy conditions during the ablation season. Peak suspended sediments were evacuated during extreme rainfall events. The estimated seasonal modern sediment erosion rate varies from 0.6 to 2.3 mm y- 1 for the study period (2009-2012). The analysis shows dominance of medium silt-sized to fine sand-sized particles having sediment size of 0.0156-0.25 mm corresponding to 70-80% without any significant seasonal variation. These transported sediments show that they are poorly sorted, coarser in nature with a nearly symmetrical to coarse skewed texture and kurtosis analysis suggesting mesokurtic distribution of sediments. The particle size fraction ranges between 4.65 and 5.23 ϕ, which is dominantly medium to coarse silty in texture. Results indicate that suspended sediments are evacuated in highly variable energy conditions through subglacial transport pathways because of increase in availability of meltwater with the progressive ablation season. Bulk geochemical characterization has been carried out to differentiate the source of suspended sediments and intensity of weathering. Chemical Index of Alterations (CIA) values of sediment flux range from 54.68 to 55.18 compared to the Upper Continental Crust (UCC) ~ 50, indicating moderate intensity of weathering. Mean seasonal (2009-2012) elemental fluxes and their contribution to the suspended sediment flux reflect that Si and Al are responsible for about 85% of

  1. Spin Transport in High-Quality Suspended Graphene Devices

    NARCIS (Netherlands)

    Guimaraes, Marcos H. D.; Veligura, A.; Zomer, P. J.; Maassen, T.; Vera-Marun, I. J.; Tombros, N.; van Arees, B. J.; Wees, B.J. van

    We measure spin transport in high mobility suspended graphene (mu approximate to 10(5)cm(2)/(V s)), obtaining a (spin) diffusion coefficient of 0.1 m(2)/s and giving a lower bound on the spin relaxation time (tau(s) approximate to 150 ps) and spin relaxation length (lambda(s) = 4.7 mu m) for

  2. Source and dispersal of suspended sediment in the macro-tidal Gulf of Kachchh

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Nath, B.N.; Vethamony, P.; Ilangovan, D.

    for Rubidium and Gallium. The suspended sediments and geochemical standards were dis- solved following acid dissolution procedure of Balaram and Rao (2002). Analysis of the resulting solutions for trace and rare earth elements was carried out with induc- tively... and movement of suspended material Movement of suspended material largely depends on prevailing hydrodynamics of the water body. Modeling the hydrodynamics coupled with dispersion can lead to a reasonable prediction for the movement pattern of sus- pended...

  3. Formation and development of a breaker bar under regular waves. Part 2: Sediment transport and morphology

    DEFF Research Database (Denmark)

    Jacobsen, Niels Gjøl; Fredsøe, Jørgen


    In Part 2 of this work, the hydrodynamic model described in Part 1 is applied for the simulation of sediment transport and the associated morphological development of breaker bars. The sediment description is split into bed load and suspended load, and like the hydrodynamics the sediment transport...... is phase-resolved in order to get on- and offshore directed contributions to the sediment transport from phase lags between the suspended sediment and the hydrodynamics.First, the sediment transport over a morphologically fixed bed of a constant slope is considered, and the transport rates are discussed......) is discussed relative to the reference simulation.The coupling between sediment transport rate and morphology is analysed and discussed. © 2014 Elsevier B.V....

  4. Parameterization of Time-Averaged Suspended Sediment Concentration in the Nearshore

    Directory of Open Access Journals (Sweden)

    Hyun-Doug Yoon


    Full Text Available To quantify the effect of wave breaking turbulence on sediment transport in the nearshore, the vertical distribution of time-averaged suspended sediment concentration (SSC in the surf zone was parameterized in terms of the turbulent kinetic energy (TKE at different cross-shore locations, including the bar crest, bar trough, and inner surf zone. Using data from a large-scale laboratory experiment, a simple relationship was developed between the time-averaged SSC and the time-averaged TKE. The vertical variation of the time-averaged SSC was fitted to an equation analogous to the turbulent dissipation rate term. At the bar crest, the proposed equation was slightly modified to incorporate the effect of near-bed sediment processes and yielded reasonable agreement. This parameterization yielded the best agreement at the bar trough, with a coefficient of determination R2 ≥ 0.72 above the bottom boundary layer. The time-averaged SSC in the inner surf zone showed good agreement near the bed but poor agreement near the water surface, suggesting that there is a different sedimentation mechanism that controls the SSC in the inner surf zone.

  5. Modeling transport and deposition of the Mekong River sediment (United States)

    Xue, Zuo; He, Ruoying; Liu, J. Paul; Warner, John C.


    A Coupled Wave–Ocean–SedimentTransport Model was used to hindcast coastal circulation and fine sedimenttransport on the Mekong shelf in southeastern Asian in 2005. Comparisons with limited observations showed that the model simulation captured the regional patterns and temporal variability of surface wave, sea level, and suspended sediment concentration reasonably well. Significant seasonality in sedimenttransport was revealed. In summer, a large amount of fluvial sediments was delivered and deposited near the MekongRiver mouth. In the following winter, strong ocean mixing, and coastal current lead to resuspension and southwestward dispersal of a small fraction of previously deposited sediments. Model sensitivity experiments (with reduced physics) were performed to investigate the impact of tides, waves, and remotely forced ambient currents on the transport and dispersal of the fluvial sediment. Strong wave mixing and downwelling-favorable coastal current associated with the more energetic northeast monsoon in the winter season are the main factors controlling the southwestward along-shelf transport.

  6. High temporal resolution in situ measurement of the effective particle size characteristics of fluvial suspended sediment. (United States)

    Williams, N D; Walling, D E; Leeks, G J L


    This paper reports the use of a LISST-100 device to monitor the effective particle size characteristics of suspended sediment in situ, and at a quasi-continuous temporal resolution. The study site was located on the River Exe at Thorverton, Devon, UK. This device has not previously been utilized in studies of fluvial suspended sediment at the storm event scale, and existing studies of suspended sediment dynamics have not involved such a high temporal resolution for extended periods. An evaluation of the field performance of the instrument is presented, with respect to innovative data collection and analysis techniques. It was found that trends in the effective particle size distribution (EPSD) and degree of flocculation of suspended sediment at the study site were highly complex, and showed significant short-term variability that has not previously been documented in the fluvial environment. The collection of detailed records of EPSD facilitated interpretation of the dynamic evolution of the size characteristics of suspended sediment, in relation to its likely source and delivery and flocculation mechanisms. The influence of measurement frequency is considered in terms of its implications for future studies of the particle size of fluvial suspended sediment employing in situ data acquisition.

  7. Effects of cadmium accumulation from suspended sediments and phytoplankton on the Oyster Saccostrea glomerata

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Helena A.; Maher, William A., E-mail:; Taylor, Anne M.; Krikowa, Frank


    Highlights: • Saccostrea glomerata accumulated cadmium from sediments and phytoplankton. • Effects were similar for both pathways. • Antioxidant capacity, lipid peroxidation and lysosomal destabilisation were affected. • Clear exposure–dose–response relationships were demonstrated. - Abstract: Metals are accumulated by filter feeding organisms via water, ingestion of suspended sediments or food. The uptake pathway can affect metal toxicity. Saccostrea glomerata were exposed to cadmium through cadmium-spiked suspended sediments (19 and 93 μg/g dry mass) and cadmium-enriched phytoplankton (1.6–3 μg/g dry mass) and cadmium uptake and effects measured. Oysters accumulated appreciable amounts of cadmium from both low and high cadmium spiked suspended sediment treatments (5.9 ± 0.4 μg/g and 23 ± 2 μg/g respectively compared to controls 0.97 ± 0.05 μg/g dry mass). Only a small amount of cadmium was accumulated by ingestion of cadmium-enriched phytoplankton (1.9 ± 0.1 μg/g compared to controls 1.2 ± 0.1 μg/g). In the cadmium spiked suspended sediment experiments, most cadmium was desorbed from sediments and cadmium concentrations in S. glomerata were significantly related to dissolved cadmium concentrations (4–21 μg/L) in the overlying water. In the phytoplankton feeding experiment cadmium concentrations in overlying water were <0.01 μg/L. In both exposure experiments, cadmium-exposed oysters showed a significant reduction in total antioxidant capacity and significantly increased lipid peroxidation and percentage of destabilised lysosomes. Destabilised lysosomes in the suspended sediments experiments also resulted from stress of exposure to the suspended sediments. The study demonstrated that exposure to cadmium via suspended sediments and to low concentrations of cadmium through the ingestion of phytoplankton, can cause sublethal stress to S. glomerata.

  8. Effects of cadmium accumulation from suspended sediments and phytoplankton on the Oyster Saccostrea glomerata

    International Nuclear Information System (INIS)

    Schmitz, Helena A.; Maher, William A.; Taylor, Anne M.; Krikowa, Frank


    Highlights: • Saccostrea glomerata accumulated cadmium from sediments and phytoplankton. • Effects were similar for both pathways. • Antioxidant capacity, lipid peroxidation and lysosomal destabilisation were affected. • Clear exposure–dose–response relationships were demonstrated. - Abstract: Metals are accumulated by filter feeding organisms via water, ingestion of suspended sediments or food. The uptake pathway can affect metal toxicity. Saccostrea glomerata were exposed to cadmium through cadmium-spiked suspended sediments (19 and 93 μg/g dry mass) and cadmium-enriched phytoplankton (1.6–3 μg/g dry mass) and cadmium uptake and effects measured. Oysters accumulated appreciable amounts of cadmium from both low and high cadmium spiked suspended sediment treatments (5.9 ± 0.4 μg/g and 23 ± 2 μg/g respectively compared to controls 0.97 ± 0.05 μg/g dry mass). Only a small amount of cadmium was accumulated by ingestion of cadmium-enriched phytoplankton (1.9 ± 0.1 μg/g compared to controls 1.2 ± 0.1 μg/g). In the cadmium spiked suspended sediment experiments, most cadmium was desorbed from sediments and cadmium concentrations in S. glomerata were significantly related to dissolved cadmium concentrations (4–21 μg/L) in the overlying water. In the phytoplankton feeding experiment cadmium concentrations in overlying water were <0.01 μg/L. In both exposure experiments, cadmium-exposed oysters showed a significant reduction in total antioxidant capacity and significantly increased lipid peroxidation and percentage of destabilised lysosomes. Destabilised lysosomes in the suspended sediments experiments also resulted from stress of exposure to the suspended sediments. The study demonstrated that exposure to cadmium via suspended sediments and to low concentrations of cadmium through the ingestion of phytoplankton, can cause sublethal stress to S. glomerata

  9. An integrated suspended sediment budgeting of the agricultural Can Revull catchment (Mallorca, Spain) (United States)

    Estrany, J.; Garcia, C.


    The Mediterranean region of Europe has a long history of human settlement and human impacts. The very high spatial and temporal variability of fluvial processes in the region also creates problems for measurement and monitoring and for assessment of effects. Extensive rainfed herbaceous crops are one of the most representative agricultural elements of this region, which should be one of the major factor 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. Sediment budgets offer a means to assess the sources, storage, rates of transport, yields, and efficiency of delivery of sediment for a range of catchment scales. Field measurements were conducted in Can Revull, a small agricultural catchment (1.03 km2) on the island of Mallorca. This study uses 137Cs measurements, sediment source fingerprinting and continuous turbidity records of four hydrological years (2004-2005 to 2007-2008) to quantify the individual components of the budget. A large proportion of the material mobilized from cultivated fields without conservation practices (gross erosion was 775 t yr-1; 1,270 t km-2 yr-1) was, however, subsequently deposited either within the field of origin (112 t yr-1; 180 t km-2 yr-1) or at intermediate locations between the source field and the channel network (field-to-channel conveyance loss was 591 t yr-1; 1,090 t km-2 yr-1). The estimates of sediment accumulation rates on the floodplain in the lower reaches of the catchment indicate that the mean sedimentation rate was 0.47 g cm-2 yr-1. This value was extrapolated to the total area of the floodplain to estimate a total annual conveyance loss or storage of 150 t yr-1. Monitoring at the catchment outlet over the study period indicated a mean annual suspended sediment yield of 7 t km-2 yr-1. The sum of the estimates of sediment yield and floodplain storage (157 t yr-1) was taken

  10. Estuarine Suspended Sediment Dynamics: Observations Derived from over a Decade of Satellite Data

    Directory of Open Access Journals (Sweden)

    Anthony Reisinger


    Full Text Available Suspended sediment dynamics of Corpus Christi Bay, Texas, USA, a shallow-water wind-driven estuary, were investigated by combining field and satellite measurements of total suspended solids (TSS. An algorithm was developed to transform 500-m Moderate Resolution Imaging Spectroradiometer (MODIS Aqua satellite reflectance data into estimated TSS values. The algorithm was developed using a reflectance ratio regression of MODIS Band 1 (red and Band 3 (green with TSS measurements (n = 54 collected by the Texas Commission on Environmental Quality for Corpus Christi Bay and other Texas estuaries. The algorithm was validated by independently collected TSS measurements during the period of 2011–2014 with an uncertainty estimate of 13%. The algorithm was applied to the period of 2002–2014 to create a synoptic time series of TSS for Corpus Christi Bay. Potential drivers of long-term variability in suspended sediment were investigated. Median and IQR composites of suspended sediments were generated for seasonal wind regimes. From this analysis it was determined that long-term, spatial patterns of suspended sediment in the estuary are related to wind-wave resuspension during the predominant northerly and prevalent southeasterly seasonal wind regimes. The impact of dredging is also apparent in long-term patterns of Corpus Christi Bay as concentrations of suspended sediments over dredge spoil disposal sites are higher and more variable than surrounding areas, which is most likely due to their less consolidated sediments and shallower depths requiring less wave energy for sediment resuspension. This study highlights the advantage of how long-synoptic time series of TSS can be used to elucidate the major drivers of suspended sediments in estuaries.

  11. Contaminated sediment transport during floods

    International Nuclear Information System (INIS)

    Fontaine, T.A.


    Over the past 48 years, operations and waste disposal activities at Oak Ridge National Laboratory have resulted in the contamination of parts of the White Oak Creek catchment. The contaminants presenting the highest risk to human health and the environment are particle reactive and are associated with the soils and sediments in the White Oak Creek drainage system. The erosion of these sediments during floods can result in the transport of contaminants both within the catchment and off-site into the Clinch River. A data collection program and a modeling investigation are being used to evaluate the probability of contaminated sediment transport during floods and to develop strategies for controlling off-site transport under present and future conditions

  12. Trapping Efficiency of Fine Sediments in Reservoir Lake in Fukushima Rivers as Revealed by Radiocaesium attached in Suspended Sediment (United States)

    Taniguchi, K.; Onda, Y.; Kuramoto, T.; Smith, H.; Blake, W.; Onuma, S.; Sato, T.; Arai, H.; Blake, W.


    Radiocaesium released from Fukushima Daiichi Nuclear Power Plant were widely distributed in the surrounded area. The radiocaesium deposited inland area were adsorbed to fine particles of the surface soils such as silt and clay particles. The contaminated particles were eroded by rainfall events, and then transported through river systems. The purpose of this research is to investigate the impact of existence of large reservoirs on the riverine transport of fine sediments by using the 137Cs as a kind of tracer. At 30 monitoring sites located in 9 river systems in the area affected by the accident, suspended sediments (SS) ware collected by time-integrated SS samplers. The particulate radiocaesium activity concentration was measured by germanium detector. The water discharge and SS flux each site were calculated by the water level and turbidity data every 10 minutes obtained by monitoring. The 137Cs flux was calculated by multiplying the activity concentration and the SS flux. The Cs-137 flux normalized by the water discharge and initial deposition of 137Cs in the watershed (L/QD) showed a correlation with the coverages of land use types in the watershed in the case of monitoring sites where there was no large reservoir in the watershed. However, at the sites that have large reservoir in the watershed, the value of L/QD were 6.5 -21 % of the values estimated by the coverage of land use types. This result implies that approximately more than 80 % of the fine SS is trapped by the reservoirs.

  13. Rans-Based Numerical Simulation of Wave-Induced Sheet-Flow Transport of Graded Sediments

    DEFF Research Database (Denmark)

    Fuhrman, David R.; Caliskan, Ugur

    An existing one-dimensional vertical (1DV) turbulence-closure flow model, coupled with sediment transport capabilities, is extended to incorporate graded sediment mixtures. The hydrodynamic model solves the horizontal component of the incompressible Reynolds-averaged Navier–Stokes (RANS) equations...... coupled with k–ω turbulence closure. In addition to standard bed and suspended load descriptions, the sediment transport model incorporates so-called high-concentration effects (turbulence damping and hindered settling velocities). The sediment transport model treats the bed and suspended load......, and then translated to a common level, which conveniently enables use of a single computational grid for the simulation of suspended sediments. Parametric study shows that these effects combine to help alleviate an otherwise systematic tendency towards over- and under- predicted transport rates for fine and coarse...

  14. Potential Impact of Climate Change on Suspended Sediment Yield in NW Spain: A Case Study on the Corbeira Catchment

    Directory of Open Access Journals (Sweden)

    M. Luz Rodríguez-Blanco


    Full Text Available Soil losses and the subsequent sediment delivery constitute significant environmental threats. Climate change is likely to have an impact on the availability of water and therefore on sediment yield in catchments. In this context, quantifying the sediment response to an increased atmospheric CO2 concentration and climate change is of utmost importance to the proper management of rural catchments. However, quantitative assessment of climate change impact remains a complex task. In this study, the potential medium (2031–2060 and long-term (2069–2098 impacts of projected changes of temperature, rainfall and CO2 concentration on sediment yield in a small rural catchment located in NW Spain were evaluated using the Soil and Water Assessment Tool (SWAT model. Climate change scenarios were created using future climate data projected by regional climate models from the ENSEMBLES project and two CO2 concentration scenarios (550 and 660 ppm. The results showed that climate change would have a noticeable impact on suspended sediment if the forecast temperature, rainfall and CO2 concentration changes included in this study were met. Overall, suspended sediment is expected to decrease (2031–2060: −11%, 2069–2098: −8% compared to the baseline period (1981–2010, mainly due to decreased streamflow. However, an increase in sediment transport in winter is predicted, possibly associated with increased erosion in cultivated areas (11%–17%, suggesting that, at this time of the year, the effect of soil detachment prevails over sediment transport capacity. Consequently, management practices aimed at reducing soil erosion in cultivated areas should be carried out, because these are the main source of sediment in the study area.

  15. Variable fractal dimension : A major control for floc structure and flocculation kinematics of suspended cohesive sediment

    NARCIS (Netherlands)

    Maggi, F.


    While the fractal dimension of suspended flocs of cohesive sediment is known to vary with the shear rate, electrochemical properties of the sediment and environment, geometrical restructuring, and presence of organic matter, experimental data presented in this work suggest changes in fractal

  16. Occurrence and persistence of fungicides in bed sediments and suspended solids from three targeted use areas in the United States (United States)

    Smalling, Kelly L.; Reilly, Timothy J.; Sandstrom, Mark W.; Kuivila, Kathryn


    To document the environmental occurrence and persistence of fungicides, a robust and sensitive analytical method was used to measure 34 fungicides and an additional 57 current-use pesticides in bed sediments and suspended solids collected from areas of intense fungicide use within three geographic areas across the United States. Sampling sites were selected near or within agricultural research farms using prophylactic fungicides at rates and types typical of their geographic location. At least two fungicides were detected in 55% of the bed and 83% of the suspended solid samples and were detected in conjunction with herbicides and insecticides. Six fungicides were detected in all samples including pyraclostrobin (75%), boscalid (53%), chlorothalonil (41%) and zoxamide (22%). Pyraclostrobin, a strobilurin fungicide, used frequently in the United States on a variety of crops, was detected more frequently than p,p′-DDE, the primary degradate of p,p′-DDT, which is typically one of the most frequently occurring pesticides in sediments collected within highly agricultural areas. Maximum fungicide concentrations in bed sediments and suspended solids were 198 and 56.7 μg/kg dry weight, respectively. There is limited information on the occurrence, fate, and persistence of many fungicides in sediment and the environmental impacts are largely unknown. The results of this study indicate the importance of documenting the persistence of fungicides in the environment and the need for a better understanding of off-site transport mechanisms, particularly in areas where crops are grown that require frequent treatments to prevent fungal diseases.

  17. Dynamic Model Of Suspended Sediment Concentration River Discharge And Rainfall Intensity At Padang Watershed North Sumatra Indonesia

    Directory of Open Access Journals (Sweden)

    Kemala Sari Lubis


    Full Text Available Abstract Sediment transport has relationship with hydrologic input primarily river discharge and rainfall intensity. Fluctuation of river discharge and rainfall intensity have great effect on suspended sediment concentration. Bayesian Dynamic Linear Model DLMs is used to study relation of input hydrology and basin response variables. Response variables were taken from suspended sediment concentration and river discharge from a year July 2012 to June 2013 at two outlets at Padang sub-watershed upstream and Padang Hilir sub-watershed downstream of Padang watershed North Sumatra. Datas were analyzed by regression analysis of Suspended Sediment Concentration SSC as a dependent variables while river discharge and rainfall intensity as independent variables. The results showed that river discharge value are the highest on July 2012 and October 2012 at upstream and downstream of Padang watershed respectively. The SSC value are the highest on July 2012 and April 2013 at upstream and downstream of Padang watershed respectively. There is a weak correlation r2 0.002 between SSC and rainfall intensity at source points of outlet at upstream of Padang watershed. There is decreasing of forest paddy and plantation areas but increasing of bush and farming areas from 2012 to 2015 at upstream of Padang watershed. Meanwhile at downstream of Padang watershed were increasing of plantation areas since 2012 to 2015

  18. Statistical analysis and estimation of annual suspended sediments of major rivers in Japan. (United States)

    Luo, Pingping; He, Bin; Chaffe, Pedro Luiz Borges; Nover, Daniel; Takara, Kaoru; Mohd Remy Rozainy, M A Z


    We evaluate the spatiotemporal trends of recent suspended sediment conditions in Japanese rivers. Statistical and spatiotemporal trend analysis is conducted on the 92 major rivers in Japan based on water quality monitoring data from 1992 to 2005. The Mann-Kendall non-parametric method was used to investigate the spatial and temporal trends for the suspended sediment indicator. Results show that the mean concentration of suspended sediments in Japanese rivers has generally declined in recent years, although there are still water quality problems at some monitoring sites (Kanto, Chubu, Kinki and Kyushu regions). A positive relationship between observed yearly discharge and suspended sediment load was found. Land use maps with 100 meter spatial resolution were used to apply an empirical model and develop a regression model for estimating annual suspended sediment loads directly from land use and hydrologic data. Rivers were assigned to three groups according to statistical cluster analysis of suspended sediment (SS) concentration. The correlation between the simulation result from the empirical model and the observed data had R(2) values of 0.62 and 0.71 for groups 2 and 3, and the correlation between the simulation result from the regression model and the observed data had R(2) values of 0.48 and 0.34 for groups 2 and 3. Results show that the proposed simulation technique can be used to predict the pollutant loads to river basins in Japan. Results also suggest prioritization methods and strategies that policy-makers can use to address suspended sediment pollution in rivers and water quality management in general.

  19. A novel method for sampling the suspended sediment load in the tidal environment using bi-directional time-integrated mass-flux sediment (TIMS) samplers (United States)

    Elliott, Emily A.; Monbureau, Elaine; Walters, Glenn W.; Elliott, Mark A.; McKee, Brent A.; Rodriguez, Antonio B.


    Identifying the source and abundance of sediment transported within tidal creeks is essential for studying the connectivity between coastal watersheds and estuaries. The fine-grained suspended sediment load (SSL) makes up a substantial portion of the total sediment load carried within an estuarine system and efficient sampling of the SSL is critical to our understanding of nutrient and contaminant transport, anthropogenic influence, and the effects of climate. Unfortunately, traditional methods of sampling the SSL, including instantaneous measurements and automatic samplers, can be labor intensive, expensive and often yield insufficient mass for comprehensive geochemical analysis. In estuaries this issue is even more pronounced due to bi-directional tidal flow. This study tests the efficacy of a time-integrated mass sediment sampler (TIMS) design, originally developed for uni-directional flow within the fluvial environment, modified in this work for implementation the tidal environment under bi-directional flow conditions. Our new TIMS design utilizes an 'L' shaped outflow tube to prevent backflow, and when deployed in mirrored pairs, each sampler collects sediment uniquely in one direction of tidal flow. Laboratory flume experiments using dye and particle image velocimetry (PIV) were used to characterize the flow within the sampler, specifically, to quantify the settling velocities and identify stagnation points. Further laboratory tests of sediment indicate that bidirectional TIMS capture up to 96% of incoming SSL across a range of flow velocities (0.3-0.6 m s-1). The modified TIMS design was tested in the field at two distinct sampling locations within the tidal zone. Single-time point suspended sediment samples were collected at high and low tide and compared to time-integrated suspended sediment samples collected by the bi-directional TIMS over the same four-day period. Particle-size composition from the bi-directional TIMS were representative of the array of

  20. A Tidally Averaged Sediment-Transport Model for San Francisco Bay, California (United States)

    Lionberger, Megan A.; Schoellhamer, David H.


    A tidally averaged sediment-transport model of San Francisco Bay was incorporated into a tidally averaged salinity box model previously developed and calibrated using salinity, a conservative tracer (Uncles and Peterson, 1995; Knowles, 1996). The Bay is represented in the model by 50 segments composed of two layers: one representing the channel (>5-meter depth) and the other the shallows (0- to 5-meter depth). Calculations are made using a daily time step and simulations can be made on the decadal time scale. The sediment-transport model includes an erosion-deposition algorithm, a bed-sediment algorithm, and sediment boundary conditions. Erosion and deposition of bed sediments are calculated explicitly, and suspended sediment is transported by implicitly solving the advection-dispersion equation. The bed-sediment model simulates the increase in bed strength with depth, owing to consolidation of fine sediments that make up San Francisco Bay mud. The model is calibrated to either net sedimentation calculated from bathymetric-change data or measured suspended-sediment concentration. Specified boundary conditions are the tributary fluxes of suspended sediment and suspended-sediment concentration in the Pacific Ocean. Results of model calibration and validation show that the model simulates the trends in suspended-sediment concentration associated with tidal fluctuations, residual velocity, and wind stress well, although the spring neap tidal suspended-sediment concentration variability was consistently underestimated. Model validation also showed poor simulation of seasonal sediment pulses from the Sacramento-San Joaquin River Delta at Point San Pablo because the pulses enter the Bay over only a few days and the fate of the pulses is determined by intra-tidal deposition and resuspension that are not included in this tidally averaged model. The model was calibrated to net-basin sedimentation to calculate budgets of sediment and sediment-associated contaminants. While

  1. Spatial and Temporal Patterns of Suspended Sediment Yields in Nested Urban Catchments (United States)

    Kemper, J. T.; Miller, A. J.; Welty, C.


    In a highly regulated area such as the Chesapeake Bay watershed, suspended sediment is a matter of primary concern. Near real-time turbidity and discharge data have been collected continuously for more than four years at five stream gages representing three nested watershed scales (1-2 sq km, 5-6 sq km, 14 sq km) in the highly impervious Dead Run watershed, located in Baltimore County, MD. Using turbidity-concentration relationships based on sample analyses at the gage site, sediment yields for each station can be quantified for a variety of temporal scales. Sediment yields have been calculated for 60+ different storms across four years. Yields show significant spatial variation, both at equivalent sub-watershed scales and from headwaters to mouth. Yields are higher at the headwater station with older development and virtually no stormwater management (DR5) than at the station with more recent development and more extensive stormwater management (DR2). However, this pattern is reversed for the stations at the next larger scale: yields are lower at DR4, downstream of DR5, than at DR3, downstream of DR2. This suggests spatial variation in the dominant sediment sources within each subwatershed. Additionally, C-Q hysteresis curves display consistent counterclockwise behavior at the DR4 station, in contrast to the consistent clockwise behavior displayed at the DR3 station. This further suggests variation in dominant sediment sources (perhaps distal vs local, respectively). We observe consistent seasonal trends in the relative magnitudes of sediment yield for different subwatersheds (e.g. DR3>DR4 in summer, DR5>DR2 in spring). We also observe significant year-to-year variation in sediment yield at the headwater and intermediate scales, whereas yields at the 14 sq km scale are largely similar across the monitored years. This observation would be consistent with the possibility that internal storage and remobilization tend to modulate downstream yields even with spatial

  2. Spatio-temporal monitoring of suspended sediments in the Solimões River (2000-2014) (United States)

    Espinoza-Villar, Raul; Martinez, Jean-Michel; Armijos, Elisa; Espinoza, Jhan-Carlo; Filizola, Naziano; Dos Santos, Andre; Willems, Bram; Fraizy, Pascal; Santini, William; Vauchel, Philippe


    The Amazon River sediment discharge has been estimated at between 600 and 1200 Mt/year, of which more than 50% comes from the Solimões River. Because of the area's inaccessibility, few studies have examined the sediment discharge spatial and temporal pattern in the upper Solimões region. In this study, we use MODIS satellite images to retrieve and understand the spatial and temporal behaviour of suspended sediments in the Solimões River from Peru to Brazil. Six virtual suspended sediment gauging stations were created along the Solimões River on a 2050-km-long transect. At each station, field-derived river discharge estimates were available and field-sampling trips were conducted for validation of remote-sensing estimates during different periods of the annual hydrological cycle between 2007 and 2014. At two stations, 10-day surface suspended sediment data were available from the SO-HYBAM monitoring program (881 field SSS samples). MODIS-derived sediment discharge closely matched the field observations, showing a relative RMSE value of 27.3% (0.48 Mtday) overall. Satellite-retrieved annual sediment discharge at the Tamshiyacu (Peru) and Manacapuru (Brazil) stations is estimated at 521 and 825 Mt/year, respectively. While upstream the river presents one main sediment discharge peak during the hydrological cycle, a secondary sediment discharge peak is detected downstream during the declining water levels, which is induced by sediment resuspension from the floodplain, causing a 72% increase on average from June to September.

  3. Sediment Transport Over Run-of-River Dams (United States)

    O'Brien, M.; Magilligan, F. J.; Renshaw, C. E.


    Dams have numerous documented effects that can degrade river habitat downstream. One significant effect of large dams is their ability to trap sediment delivered from upstream. This trapping can alter sediment transport and grain size downstream - effects that often motivate dam removal decisions. However, recent indirect observations and modeling studies indicate that small, run-of-river (ROR) dams, which do not impede discharge, may actually leak sediment downstream. However, there are no direct measurements of sediment flux over ROR dams. This study investigates flow and sediment transport over four to six different New England ROR dams over a summer-fall field season. Sediment flux was measured using turbidity meters and tracer (RFID) cobbles. Sediment transport was also monitored through an undammed control site and through a river where two ROR dams were recently removed. These data were used to predict the conditions that contribute to sediment transport and trapping. Year 1 data show that tracer rocks of up to 61 mm were transported over a 3 m ROR dam in peak flows of 84% of bankfull stage. These tracer rocks were transported over and 10 m beyond the dam and continue to move downstream. During the same event, comparable suspended sediment fluxes of up to 81 g/s were recorded both upstream and downstream of the dam at near-synchronous timestamps. These results demonstrate the potential for sediment transport through dammed rivers, even in discharge events that do not exceed bankfull. This research elucidates the effects of ROR dams and the controls on sediment transport and trapping, contributions that may aid in dam management decisions.

  4. Assessing the occurrence and distribution of pyrethroids in water and suspended sediments (United States)

    Hladik, M.L.; Kuivila, K.M.


    The distribution of pyrethroid insecticides in the environment was assessed by separately measuring concentrations in the dissolved and suspended sediment phases of surface water samples. Filtered water was extracted by HLB solid-phase extraction cartridges, while the sediment on the filter was sonicated and cleaned up using carbon and aluminum cartridges. Detection limits for the 13 pyrethroids analyzed by gas chromatography-tandem mass spectrometry were 0.5 to 1 ng L-1 for water and 2 to 6 ng g for the suspended sediments. Seven pyrethroids were detected in six water samples collected from either urban or agricultural creeks, with bifenthrin detected the most frequently and at the highest concentrations. In spiked water samples and field samples, the majority of the pyrethroids were associated with the suspended sediments.

  5. Sub-daily variability of suspended sediment fluxes in small mountainous catchments &ndash implications for community-based river monitoring (United States)

    Duvert, C.; Gratiot, N.; Némery, J.; Burgos, A.; Navratil, O.


    Accurate estimates of suspended sediment yields depend on effective monitoring strategies. In mountainous environments undergoing intense seasonal precipitation, the implementation of such monitoring programs relies primarily on a rigorous study of the temporal variability of fine sediment transport. This investigation focuses on seasonal and short-term variability in suspended sediment flux in a subhumid region of the Mexican Volcanic Belt. Intensive monitoring was conducted during one year in four contrasting catchments (3 to 630 km2). Analyses revealed significant temporal variability in suspended sediment export over various time scales, with between 63 and 97% of the annual load exported in as little as 2% of the time. Statistical techniques were used to evaluate the sampling frequency required to get reliable estimates of annual sediment yield at the four sites. A bi-daily sampling scheme would be required at the outlet of the 630 km2 catchment, whereas in the three smaller catchments (3-12 km2), accurate estimates would inevitably require hourly monitoring. At the larger catchment scale, analysis of the sub-daily variability of fine sediment fluxes showed that the frequency of sampling could be lowered by up to 100% (i.e. from bi-daily to daily) if a specific and regular sampling time in the day was considered. In contrast, conducting a similar sampling strategy at the three smaller catchments could lead to serious misinterpretation (i.e. up to 1000% error). Our findings emphasise the importance of an analysis of the sub-daily variability of sediment fluxes in mountainous catchments. Characterising this variability may offer useful insights for improving the effectiveness of community-based monitoring strategies in rural areas of developing countries. In regions where historical records based on discrete sampling are available, it may also help assessing the quality of past flux estimates. Finally, the study confirms the global necessity of acquiring more

  6. Sediment transport under breaking waves

    DEFF Research Database (Denmark)

    Christensen, Erik Damgaard; Hjelmager Jensen, Jacob; Mayer, Stefan


    generated at the surface where the wave breaks as well as the turbulence generated near the bed due to the wave-motion and the undertow. In general, the levels of turbulent kinetic energy are found to be higher than experiments show. This results in an over prediction of the sediment transport. Nevertheless...

  7. Vertical Distribution of Suspended Sediment under Steady Flow: Existing Theories and Fractional Derivative Model

    Directory of Open Access Journals (Sweden)

    Shiqian Nie


    Full Text Available The fractional advection-diffusion equation (fADE model is a new approach to describe the vertical distribution of suspended sediment concentration in steady turbulent flow. However, the advantages and parameter definition of the fADE model in describing the sediment suspension distribution are still unclear. To address this knowledge gap, this study first reviews seven models, including the fADE model, for the vertical distribution of suspended sediment concentration in steady turbulent flow. The fADE model, among others, describes both Fickian and non-Fickian diffusive characteristics of suspended sediment, while the other six models assume that the vertical diffusion of suspended sediment follows Fick’s first law. Second, this study explores the sensitivity of the fractional index of the fADE model to the variation of particle sizes and sediment settling velocities, based on experimental data collected from the literatures. Finally, empirical formulas are developed to relate the fractional derivative order to particle size and sediment settling velocity. These formulas offer river engineers a substitutive way to estimate the fractional derivative order in the fADE model.

  8. On The Ubiquity of Nonstationary Fluvial Suspended Sediment Dynamics: A Call for Long Term Monitoring and Dynamical Sediment Management Strategies (United States)

    Gray, A. B.


    Watersheds with sufficient monitoring data have been predominantly found to display nonstationary suspended sediment dynamics, whereby the relationship between suspended sediment concentration and discharge changes over time. Despite the importance of suspended sediment as a keystone of geophysical and biochemical processes, and as a primary mediator of water quality, stationary behavior remains largely assumed in the context of these applications. This study presents an investigation into the time dependent behavior of small mountainous rivers draining the coastal ranges of the western continental US over interannual to interdecadal time scales. Of the 250+ small coastal (drainage area systems. Temporal patterns of non-stationary behavior provided some evidence for spatial coherence, which may be related to synoptic hydro-metrological patterns and regional scale changes in land use patterns. However, the results also highlight the complex, integrative nature of watershed scale fluvial suspended sediment dynamics. This underscores the need for in-depth, forensic approaches for initial processes identification, which require long term, high resolution monitoring efforts in order to adequately inform management. The societal implications of nonstationary sediment dynamics and their controls were further explored through the case of California, USA, where over 150 impairment listings have resulted in more than 50 sediment TMDLs, only 3 of which are flux based - none of which account for non-stationary behavior.

  9. Storm Event Suspended Sediment-Discharge Hysteresis and Controls in Agricultural Watersheds: Implications for Watershed Scale Sediment Management. (United States)

    Sherriff, Sophie C; Rowan, John S; Fenton, Owen; Jordan, Philip; Melland, Alice R; Mellander, Per-Erik; hUallacháin, Daire Ó


    Within agricultural watersheds suspended sediment-discharge hysteresis during storm events is commonly used to indicate dominant sediment sources and pathways. However, availability of high-resolution data, qualitative metrics, longevity of records, and simultaneous multiwatershed analyses has limited the efficacy of hysteresis as a sediment management tool. This two year study utilizes a quantitative hysteresis index from high-resolution suspended sediment and discharge data to assess fluctuations in sediment source location, delivery mechanisms and export efficiency in three intensively farmed watersheds during events over time. Flow-weighted event sediment export was further considered using multivariate techniques to delineate rainfall, stream hydrology, and antecedent moisture controls on sediment origins. Watersheds with low permeability (moderately- or poorly drained soils) with good surface hydrological connectivity, therefore, had contrasting hysteresis due to source location (hillslope versus channel bank). The well-drained watershed with reduced connectivity exported less sediment but, when watershed connectivity was established, the largest event sediment load of all watersheds occurred. Event sediment export was elevated in arable watersheds when low groundcover was coupled with high connectivity, whereas in the grassland watershed, export was attributed to wetter weather only. Hysteresis analysis successfully indicated contrasting seasonality, connectivity and source availability and is a useful tool to identify watershed specific sediment management practices.

  10. The effect of source suspended sediment concentration on the sediment dynamics of a macrotidal creek and salt marsh (United States)

    Poirier, Emma; van Proosdij, Danika; Milligan, Timothy G.


    Seasonal variability in the sediment dynamics of a Bay of Fundy tidal creek and salt marsh system was analyzed to better understand the ecomorphodynamics of a high suspended sediment concentration intertidal habitat. Data were collected over 62 tides for velocity, suspended sediment concentration, deposition, and grain size at four stations from the creek thalweg to the marsh surface. Five topographic surveys were also conducted throughout the 14-month study. Deposition rates per tide varied spatially from 56.4 g m-2 at the creek thalweg to 15.3 g m-2 at the marsh surface. Seasonal variations in deposition in the creek and marsh surface were from 38.0 g m-2 to 97.7 g m-2 and from 12.2 g m-2 to 19.6 g m-2 respectively. Deposition and erosion were greatest in late fall and winter. This seasonal change, led by higher suspended sediment concentrations, was observed in the creek and at the marsh bank but notably absent from the marsh edge and marsh surface. Sediments were predominantly deposited in floc form (76-83%). Because of high floc content, higher suspended sediment concentrations led to more rapid loss of sediment from suspension. With increasing sediment concentration, deposition increased in the tidal creek and at the marsh bank but not at the marsh edge or marsh surface. This suggests that in highly flocculated environments the water column clears fast enough that very little sediment remains in suspension when the water reaches the marsh and that the sediment concentration during marsh inundation is independent of the initial concentration in the creek.

  11. Longshore sediment transport along the Indian coast

    Digital Repository Service at National Institute of Oceanography (India)

    Chandramohan, P.; Nayak, B.U.

    An empirical sediment transport model has been developed based on longshore energy flux equation. Ship reported waves, published in Indian Daily Weather Reports, are compiled for 19 y and used for estimation of sediment transport. Annual gross...

  12. Streamflow and Suspended-Sediment Loads Before and During Highway Construction, North Halawa, Haiku, and Kamooalii Drainage Basins, Oahu, Hawaii, 1983-91 (United States)

    Hill, Barry R.


    Concern over potential effects from construction of the H-3 highway on Oahu, Hawaii, prompted a long-term study of streamflow and suspended-sediment transport at a network of five stream-gaging stations along the highway route. This report presents results for 1983-91, which included pre-construction and construction periods at all stream-gaging stations. Annual rainfall, streamflow, and suspended-sediment loads were generally higher during construction than before construction. Data collected before and during construction were compared using analysis of covariance to determine whether streamflow and suspended-sediment loads changed significantly during construction after accounting for effects of increased rainfall. Streamflow at stream-gaging stations was compared with streamflow at an index stream-gaging station unaffected by construction. Streamflow data were divided into low- and high-flow classes, and the two flow classes were analyzed separately. Low flows increased 117 percent during construction at one station. This increase probably was related to the removal of vegetation for highway construction. Low flows decreased 28 percent at another station, probably as a result of increased ground-water withdrawals and highway construction activities. No significant changes in low flows were detected at the other stations, and no significant changes in high flows were detected at any stations. Suspended-sediment loads increased significantly during construction at three stations. Highway construction contributed between 56 and 76 percent of the suspended-sediment loads measured at these stations during construction. Loads did not change significantly at a station downstream of a reservoir, and loads decreased at a station downstream of a drainage basin that was heavily used for agriculture before construction. Suspended-sediment concentrations were used to assess compliance with applicable State water-quality standards. State water-quality standards for suspended

  13. A suspended sediment yield predictive equation for river basins in ...

    African Journals Online (AJOL)

    Since many stream gauging stations in the country have no records on fluvial sediment, the empirical equation can be used to obtain preliminary estimates of expected sediment load of streams for engineering design of hydraulic structures such as reservoirs. Journal of Applied Science and Technology (JAST) , Vol. 5, Nos.

  14. Sr and Nd isotopes of suspended sediments from rivers of the Amazon basin (United States)

    Hatting, Karina; Santos, Roberto V.; Sondag, Francis


    The Rb-Sr and Sm-Nd isotopic systems are important tools to constrain the provenance of sediment load in river systems. This study presents the isotopic composition of Sr and Nd isotopes and major and minor elements in suspended sediments from the Marañón-Solimões, Amazonas and Beni-Madeira rivers. The data were used to constrain the source region of the sediments and to better understand the main seasonal and spatial transport processes within the basin based on the variations of the chemical and isotopic signals. They also allow establishing a relationship between sediment concentrations and flow rate values. The study presents data collected during a hydrological year between 2009 and 2010. The Marañón-Solimões River presents low Sr isotopic values (0.7090-0.7186), broad EpslonNd(0) range (-15.17 to -8.09) and Nd model (TDM) ages varying from 0.99 to 1.81 Ga. Sources of sediments to the Marañón-Solimões River include recent volcanic rocks in northern Peru and Ecuador, as well as rocks with long crustal residence time and carbonates from the Marañón Basin, Peru. The Beni-Madeira River has more radiogenic Sr isotope values (0.7255-0.7403), more negative EpslonNd(0) values (-20.46 to -10.47), and older Nd isotope model ages (from 1.40 to 2.35 Ga) when compared to the Marañón-Solimões River. These isotope data were related to the erosion of Paleozoic and Cenozoic foreland basins that are filled with Precambrian sediments derived from the Amazonian Craton. These basins are located in Bolivian Subandina Zone. The Amazon River presents intermediate isotopic values when compared to those found in the Marañón-Solimões and Beni-Madeira rivers. Its Sr isotope ratios range between 0.7193 and 0.7290, and its EpslonNd(0) values varies between -11.09 and -9.51. The Nd isotope model ages of the suspended sediments vary between 1.28 and 1.77 Ga. Concentrations of soluble and insoluble elements indicate a more intense weathering activity in sediments of the Beni

  15. Retrieval of suspended sediment concentrations using Landsat-8 OLI satellite images in the Orinoco River (Venezuela) (United States)

    Yepez, Santiago; Laraque, Alain; Martinez, Jean-Michel; De Sa, Jose; Carrera, Juan Manuel; Castellanos, Bartolo; Gallay, Marjorie; Lopez, Jose L.


    In this study, 81 Landsat-8 scenes acquired from 2013 to 2015 were used to estimate the suspended sediment concentration (SSC) in the Orinoco River at its main hydrological station at Ciudad Bolivar, Venezuela. This gauging station monitors an upstream area corresponding to 89% of the total catchment area where the mean discharge is of 33,000 m3·s-1. SSC spatial and temporal variabilities were analyzed in relation to the hydrological cycle and to local geomorphological characteristics of the river mainstream. Three types of atmospheric correction models were evaluated to correct the Landsat-8 images: DOS, FLAASH, and L8SR. Surface reflectance was compared with monthly water sampling to calibrate a SSC retrieval model using a bootstrapping resampling. A regression model based on surface reflectance at the Near-Infrared wavelengths showed the best performance: R2 = 0.92 (N = 27) for the whole range of SSC (18 to 203 mg·l-1) measured at this station during the studied period. The method offers a simple new approach to estimate the SSC along the lower Orinoco River and demonstrates the feasibility and reliability of remote sensing images to map the spatiotemporal variability in sediment transport over large rivers.

  16. Simulation of hydrologic conditions and suspended-sediment loads in the San Antonio River Basin downstream from San Antonio, Texas, 2000-12 (United States)

    Banta, J. Ryan; Ockerman, Darwin J.


    Suspended sediment in rivers and streams can play an important role in ecological health of rivers and estuaries and consequently is an important issue for water-resource managers. To better understand suspended-sediment loads and transport in a watershed, the U.S. Geological Survey (USGS), in cooperation with the San Antonio River Authority, developed a Hydrological Simulation Program—FORTRAN model to simulate hydrologic conditions and suspended-sediment loads during 2000–12 for four watersheds, which comprise the overall study area in the San Antonio River Basin (hereinafter referred to as the “USGS–2014 model”). The study area consists of approximately 2,150 square miles encompassing parts of Bexar, Guadalupe, Wilson, Karnes, DeWitt, Goliad, Victoria, and Refugio Counties. The USGS–2014 model was calibrated for hydrology and suspended sediment for 2006–12. Overall, model-fit statistics and graphic evaluations from the calibration and testing periods provided multiple lines of evidence indicating that the USGS–2014 model simulations of hydrologic and suspended-sediment conditions were mostly “good” to “very good.” Model simulation results indicated that approximately 1,230 tons per day of suspended sediment exited the study area and were delivered to the Guadalupe River during 2006–12, of which approximately 62 percent originated upstream from the study area. Sample data and simulated model results indicate that most of the suspended-sediment load in the study area consisted of silt- and clay-sized particles (less than 0.0625 millimeters). The Cibolo Creek watershed was the largest contributor of suspended sediment from the study area. For the entire study area, open/developed land and cropland exhibited the highest simulated soil erosion rates; however, the largest contributions of sediment (by land-cover type) were pasture and forest/rangeland/shrubland, which together composed approximately 80 percent of the land cover of the

  17. Suspended sediment measurements in the Llobregat River Mouth

    International Nuclear Information System (INIS)

    Sotillo Membibre, M.


    Sediment concentrations were measured at the Llobregat river mouth near Barcelona, using an ADCP. the ADCP backscatter intensity was corrected fro sound loss in the water column and was calibrated to sediment concentrations on the basis of water samples, that were taken in the water column. This holds for cases where particles are small compared to the acoustic were length so that the Rayleigh scattering law applies, which is true the ADCP. (Author)

  18. RANS-based simulation of wave-induced sheet-flow transport of graded sediments

    DEFF Research Database (Denmark)

    Calistan, Ugur; Fuhrman, David R.


    A one-dimensional vertical (1DV) turbulence-closure flow model, coupled with sediment transport capabilities,is extended to incorporate graded sediment mixtures. The hydrodynamic model solves the horizontalcomponent of the incompressible Reynolds-averaged Navier–Stokes (RANS) equations coupled...... with k–ωturbulence closure. The sediment transport description includes both bed and suspended load descriptions. Socalledhigh-concentration effects (turbulence damping and hindered settling velocities) are likewise included.The sediment transport model treats the bed and suspended load individually....... The sediment transport model is validated against sheet-flow experimentaloscillatory tunnel measurements beneath velocity-skewed wave signals, and demonstrates similar accuracy(transport rates generally within a factor of two) for both graded and uniform sands. The model is likewisevalidated against...

  19. Suspended-sediment loads in the lower Stillaguamish River, Snohomish County, Washington, 2014–15 (United States)

    Anderson, Scott A.; Curran, Christopher A.; Grossman, Eric E.


    Continuous records of discharge and turbidity at a U.S. Geological Survey (USGS) streamgage in the lower Stillaguamish River were paired with discrete measurements of suspended-sediment concentration (SSC) in order to estimate suspended-sediment loads over the water years 2014 and 2015. First, relations between turbidity and SSC were developed and used to translate the continuous turbidity record into a continuous estimate of SSC. Those concentrations were then used to predict suspended-sediment loads based on the current discharge record, reported at daily intervals. Alternative methods were used to in-fill a small number of days with either missing periods of turbidity or discharge records. Uncertainties in our predictions at daily and annual time scales were estimated based on the parameter uncertainties in our turbidity-SSC regressions. Daily loads ranged from as high as 121,000 tons during a large autumn storm to as low as –56 tons, when tidal return flow moved more sediment upstream than river discharge did downstream. Annual suspended-sediment loads for both water years were close to 1.4 ± 0.2 million tons.

  20. Temporal variability in the suspended sediment load and streamflow of the Doce River (United States)

    Oliveira, Kyssyanne Samihra Santos; Quaresma, Valéria da Silva


    Long-term records of streamflow and suspended sediment load provide a better understanding of the evolution of a river mouth, and its adjacent waters and a support for mitigation programs associated with extreme events and engineering projects. The aim of this study is to investigate the temporal variability in the suspended sediment load and streamflow of the Doce River to the Atlantic Ocean, between 1990 and 2013. Streamflow and suspended sediment load were analyzed at the daily, seasonal, and interannual scales. The results showed that at the daily scale, Doce River flood events are due to high intensity and short duration rainfalls, which means that there is a flashy response to rainfall. At the monthly and season scales, approximately 94% of the suspended sediment supply occurs during the wet season. Extreme hydrological events are important for the interannual scale for Doce River sediment supply to the Atlantic Ocean. The results suggest that a summation of anthropogenic interferences (deforestation, urbanization and soil degradation) led to an increase of extreme hydrological events. The findings of this study shows the importance of understanding the typical behavior of the Doce River, allowing the detection of extreme hydrological conditions, its causes and possible environmental and social consequences.

  1. Response of suspended sediment concentration to tidal dynamics at a site inside the mouth of an inlet: Jiaozhou Bay (China

    Directory of Open Access Journals (Sweden)

    S. L. Yang


    Full Text Available Observations of fair weather currents and suspended sediment concentrations (SSC were made using an acoustic Doppler current profiler and two YSI turbidity sensors over a neap to spring time cycle at a site near the inner mouth of a semi-enclosed mesotidal-macrotidal embayment (Jiaozhou Bay to examine the influence of tidal dynamics on concentration and transport of suspended sediment. During the investigation, SSC varied from about 3 to 16 mg L–1 at the surface and about 6 to 40 mg L–1 close to the bed, while the current velocity reached 79 cm s–1 at the surface and 61 cm s–1 near the bed. SSC was tidally cyclic. The near-bed instantaneous SSC was closely related to current velocity with almost no time lag, indicating that the variability of SSC was governed by current-induced settling/resuspension. At the surface, however, instantaneous SSC was poorly related to instantaneous current velocity because the peak SSC tended to occur around ebb slack water. This suggests that the surface SSC was controlled by horizontal advection from landward higher concentration areas. Both at the surface and near the bed, on the other hand, tidally-averaged SSC was well correlated to tidal range and current speed. Current velocity and SSC were flood-dominated for all the tides investigated, which resulted in significant landward residual suspended sediment transport at the study site. The observed flood dominance was mainly attributed to the location of the study site on the landward side of the bay’s inlet where flow separation is favoured during flood tide. It was concluded that tides are the dominant hydrodynamic component controlling the variability of SSC during fair weather at the study area. Keywords: sediment, concentration, suspension, advection, currents, shoalling effect, Jiaozhou Bay, China

  2. Determining the sources of suspended sediment in a Mediterranean groundwater-dominated river: the Na Borges basin (Mallorca, Spain). (United States)

    Estrany, Joan; Martinez-Carreras, Nuria


    Tracers have been acknowledged as a useful tool to identify sediment sources, based upon a variety of techniques and chemical and physical sediment properties. Sediment fingerprinting supports the notion that changes in sedimentation rates are not just related to increased/reduced erosion and transport in the same areas, but also to the establishment of different pathways increasing sediment connectivity. The Na Borges is a Mediterranean lowland agricultural river basin (319 km2) where traditional soil and water conservation practices have been applied over millennia to provide effective protection of cultivated land. During the twentieth century, industrialisation and pressure from tourism activities have increased urbanised surfaces, which have impacts on the processes that control streamflow. Within this context, source material sampling was focused in Na Borges on obtaining representative samples from potential sediment sources (comprised topsoil; i.e., 0-2 cm) susceptible to mobilisation by water and subsequent routing to the river channel network, while those representing channel bank sources were collected from actively eroding channel margins and ditches. Samples of road dust and of solids from sewage treatment plants were also collected. During two hydrological years (2004-2006), representative suspended sediment samples for use in source fingerprinting studies were collected at four flow gauging stations and at eight secondary sampling points using time-integrating sampling samplers. Likewise, representative bed-channel sediment samples were obtained using the resuspension approach at eight sampling points in the main stem of the Na Borges River. These deposits represent the fine sediment temporarily stored in the bed-channel and were also used for tracing source contributions. A total of 102 individual time-integrated sediment samples, 40 bulk samples and 48 bed-sediment samples were collected. Upon return to the laboratory, source material samples were

  3. Sediment transport in the lower Snake and Clearwater River Basins, Idaho and Washington, 2008–11 (United States)

    Clark, Gregory M.; Fosness, Ryan L.; Wood, Molly S.


    Sedimentation is an ongoing maintenance problem for reservoirs, limiting reservoir storage capacity and navigation. Because Lower Granite Reservoir in Washington is the most upstream of the four U.S. Army Corps of Engineers reservoirs on the lower Snake River, it receives and retains the largest amount of sediment. In 2008, in cooperation with the U.S. Army Corps of Engineers, the U.S. Geological Survey began a study to quantify sediment transport to Lower Granite Reservoir. Samples of suspended sediment and bedload were collected from streamgaging stations on the Snake River near Anatone, Washington, and the Clearwater River at Spalding, Idaho. Both streamgages were equipped with an acoustic Doppler velocity meter to evaluate the efficacy of acoustic backscatter for estimating suspended-sediment concentrations and transport. In 2009, sediment sampling was extended to 10 additional locations in tributary watersheds to help identify the dominant source areas for sediment delivery to Lower Granite Reservoir. Suspended-sediment samples were collected 9–15 times per year at each location to encompass a range of streamflow conditions and to capture significant hydrologic events such as peak snowmelt runoff and rain-on-snow. Bedload samples were collected at a subset of stations where the stream conditions were conducive for sampling, and when streamflow was sufficiently high for bedload transport. At most sampling locations, the concentration of suspended sediment varied by 3–5 orders of magnitude with concentrations directly correlated to streamflow. The largest median concentrations of suspended sediment (100 and 94 mg/L) were in samples collected from stations on the Palouse River at Hooper, Washington, and the Salmon River at White Bird, Idaho, respectively. The smallest median concentrations were in samples collected from the Selway River near Lowell, Idaho (11 mg/L), the Lochsa River near Lowell, Idaho (11 mg/L), the Clearwater River at Orofino, Idaho (13 mg

  4. Sediment transport on the Palos Verdes shelf, California (United States)

    Ferre, B.; Sherwood, C.R.; Wiberg, P.L.


    Sediment transport and the potential for erosion or deposition have been investigated on the Palos Verdes (PV) and San Pedro shelves in southern California to help assess the fate of an effluent-affected deposit contaminated with DDT and PCBs. Bottom boundary layer measurements at two 60-m sites in spring 2004 were used to set model parameters and evaluate a one-dimensional (vertical) model of local, steady-state resuspension, and suspended-sediment transport. The model demonstrated skill (Brier scores up to 0.75) reproducing the magnitudes of bottom shear stress, current speeds, and suspended-sediment concentrations measured during an April transport event, but the model tended to underpredict observed rotation in the bottom-boundary layer, possibly because the model did not account for the effects of temperature-salinity stratification. The model was run with wave input estimated from a nearby buoy and current input from four to six years of measurements at thirteen sites on the 35- and 65-m isobaths on the PV and San Pedro shelves. Sediment characteristics and erodibility were based on gentle wet-sieve analysis and erosion-chamber measurements. Modeled flow and sediment transport were mostly alongshelf toward the northwest on the PV shelf with a significant offshore component. The 95th percentile of bottom shear stresses ranged from 0.09 to 0.16 Pa at the 65-m sites, and the lowest values were in the middle of the PV shelf, near the Whites Point sewage outfalls where the effluent-affected layer is thickest. Long-term mean transport rates varied from 0.9 to 4.8 metric tons m-1 yr-1 along the 65-m isobaths on the PV shelf, and were much higher at the 35-m sites. Gradients in modeled alongshore transport rates suggest that, in the absence of a supply of sediment from the outfalls or PV coast, erosion at rates of ???0.2 mm yr-1 might occur in the region southeast of the outfalls. These rates are small compared to some estimates of background natural sedimentation

  5. Estimation of suspended sediment concentration from Acoustic Doppler Current Profiler (ADCP) instrument: A case study of Lembeh Strait, North Sulawesi (United States)

    Dwinovantyo, Angga; Manik, Henry M.; Prartono, Tri; Susilohadi; Ilahude, Delyuzar


    Measurement of suspended sediment concentration (SSC) is one of the parameters needed to determine the characteristics of sediment transport. However, the measurement of SSC nowadays still uses conventional technique and it has limitations; especially in temporal resolution. With advanced technology, the measurement can use hydroacoustic technology such as Acoustic Doppler Current Profiler (ADCP). ADCP measures the intensity of backscatter as echo intensity unit from sediment particles. The frequency of ADCP used in this study was 400 kHz. The samples were measured and collected from Lembeh Strait, North Sulawesi. The highest concentration of suspended sediment was 98.89 mg L-1 and the lowest was 45.20 mg L-1. Time series data showed the tidal condition affected the SSC. From the research, we also made correction from sound signal losses effect such as spherical spreading and sound absorption to get more accurate results by eliminating these parameters in echo intensity data. Simple linear regression analysis at echo intensity measured from ADCP to direct measurement of SSC was performed to obtain the estimation of the SSC. The comparison result of estimation of SSC from ADCP measurements and SSC from laboratory analyses was insignificantly different based on t-test statistical analysis with 95% confidence interval percentage.

  6. Sources of suspended-sediment loads in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary, south Texas, 1958–2010 (United States)

    Ockerman, Darwin J.; Heitmuller, Franklin T.; Wehmeyer, Loren L.


    The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers, Fort Worth District; City of Corpus Christi; Guadalupe-Blanco River Authority; San Antonio River Authority; and San Antonio Water System, developed, calibrated, and tested a Hydrological Simulation Program-FORTRAN (HSPF) watershed model to simulate streamflow and suspended-sediment concentrations and loads during 1958-2010 in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary in south Texas. Data available to simulate suspended-sediment concentrations and loads consisted of historical sediment data collected during 1942-82 in the study area and suspended-sediment concentration data collected periodically by the USGS during 2006-7 and 2010 at three USGS streamflow-gaging stations (08211000 Nueces River near Mathis, Tex. [the Mathis gage], 08211200 Nueces River at Bluntzer, Tex. [the Bluntzer gage], and 08211500 Nueces River at Calallen, Tex. [the Calallen gage]), and at one ungaged location on a Nueces River tributary (USGS station 08211050 Bayou Creek at Farm Road 666 near Mathis, Tex.). The Mathis gage is downstream from Wesley E. Seale Dam, which was completed in 1958 to impound Lake Corpus Christi. Suspended-sediment data collected before and after completion of Wesley E. Seale Dam provide insights to the effects of the dam and reservoir on suspended-sediment loads transported by the lower Nueces River downstream from the dam to the Nueces Estuary. Annual suspended-sediment loads at the Nueces River near the Mathis, Tex., gage were considerably lower for a given annual mean discharge after the dam was completed than before the dam was completed.

  7. River suspended sediment modelling using the CART model: A comparative study of machine learning techniques. (United States)

    Choubin, Bahram; Darabi, Hamid; Rahmati, Omid; Sajedi-Hosseini, Farzaneh; Kløve, Bjørn


    Suspended sediment load (SSL) modelling is an important issue in integrated environmental and water resources management, as sediment affects water quality and aquatic habitats. Although classification and regression tree (CART) algorithms have been applied successfully to ecological and geomorphological modelling, their applicability to SSL estimation in rivers has not yet been investigated. In this study, we evaluated use of a CART model to estimate SSL based on hydro-meteorological data. We also compared the accuracy of the CART model with that of the four most commonly used models for time series modelling of SSL, i.e. adaptive neuro-fuzzy inference system (ANFIS), multi-layer perceptron (MLP) neural network and two kernels of support vector machines (RBF-SVM and P-SVM). The models were calibrated using river discharge, stage, rainfall and monthly SSL data for the Kareh-Sang River gauging station in the Haraz watershed in northern Iran, where sediment transport is a considerable issue. In addition, different combinations of input data with various time lags were explored to estimate SSL. The best input combination was identified through trial and error, percent bias (PBIAS), Taylor diagrams and violin plots for each model. For evaluating the capability of the models, different statistics such as Nash-Sutcliffe efficiency (NSE), Kling-Gupta efficiency (KGE) and percent bias (PBIAS) were used. The results showed that the CART model performed best in predicting SSL (NSE=0.77, KGE=0.8, PBIAS<±15), followed by RBF-SVM (NSE=0.68, KGE=0.72, PBIAS<±15). Thus the CART model can be a helpful tool in basins where hydro-meteorological data are readily available. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Quasi-Three-Dimensional Mathematical Modeling of Morphological Processes Based on Equilibrium Sediment Transport (United States)

    Charafi, My. M.; Sadok, A.; Kamal, A.; Menai, A.

    A quasi-three-dimensional mathematical model has been developed to study the morphological processes based on equilibrium sediment transport method. The flow velocities are computed by a two-dimensional horizontal depth-averaged flow model (H2D) in combination with logarithmic velocity profiles. The transport of sediment particles by a flow water has been considered in the form of bed load and suspended load. The bed load transport rate is defined as the transport of particles by rolling and saltating along the bed surface and is given by the Van Rijn relationship (1987). The equilibrium suspended load transport is described in terms of an equilibrium sediment concentration profile (ce) and a logarithmic velocity (u). Based on the equilibrium transport, the bed change rate is given by integration of the sediment mass-balance equation. The model results have been compared with a Van Rijn results (equilibrium approach) and good agreement has been found.

  9. Sub-daily variability of suspended sediment fluxes in small mountainous catchments - implications for community-based river monitoring (United States)

    Duvert, C.; Gratiot, N.; Némery, J.; Burgos, A.; Navratil, O.


    Accurate estimates of suspended sediment yields depend on effective monitoring strategies. In mountainous environments undergoing intense seasonal precipitation, the implementation of such monitoring programs relies primarily on a rigorous study of the temporal variability of fine sediment transport. This investigation focuses on seasonal and short-term sediment variability in a subhumid region of the Mexican Volcanic Belt. Intensive hydrosedimentary monitoring was conducted during one year on four contrasting catchments (3 to 630 km2). Analyses revealed significant temporal variability in suspended sediment export over various time scales, with between 63 and 97% of the annual load exported in as little as 2% of the time. Statistical techniques were used to evaluate the sampling frequency required to get reliable annual sediment yield estimates at the four sites. A bi-daily sampling would be required at the outlet of the 630-km2 catchment, whereas in the three smaller catchments (3-12 km2), the achievement of accurate estimates would inevitably require hourly monitoring. At the larger catchment scale, analysis of the sub-daily variability of fine sediment fluxes showed that the frequency of sampling could be lowered by up to 100% (i.e. from bi-daily to daily) if considering a specific and regular sampling time in the day. In contrast, conducting a similar sampling strategy at the three smaller catchments could lead to serious misinterpretation (i.e. up to 1000% error). Our findings emphasise the importance of an analysis of the sub-daily variability of sediment fluxes in mountainous catchments. Characterising this variability may offer useful insights for improving the effectiveness of community-based monitoring strategies in rural areas of developing countries. In regions where historical records based on discrete sampling are available, it may also help assessing the quality of past flux estimates. Finally, the study confirms the global necessity of acquiring

  10. Numerical modeling of suspended sediment tansfers at the catchment scale with TELEMAC (United States)

    Taccone, Florent; Antoine, Germain; Delestre, Olivier; Goutal, Nicole


    Water equations. The numerical scheme developed by Chen and Noelle (2015) appears to be the best compromise between robustness and accuracy. The sediment transport module SISYPHE of TELEMAC-MASCARET is also used for simulating suspended sediment transport and erosion in this configuration. Then, an application to a real, well-documented watershed is performed. With a total area of 86.4 ha, the Laval watershed is located in the Southern French Alps. It takes part of the Draix-Bleone Observatory, on which 30 years of collected data are available. On this site, several rainfall events have been simulated using high performance clusters and parallelized computation methods. The results show a good robustness and accuracy of the chosen numerical schemes for hydraulic and sediment transport. Furthermore, a good agreement with measured data is obtain if an infiltration model is added to the Shallow Water equations. This study gives promising perspectives for simulating sediment transfers at the catchment scale with a physically based approach. G. Chen et S. Noelle: A new hydrostatic reconstruction scheme motivated by the wet-dry front. 2015. G. Kirstetter et al: Modeling rain-driven overland fow: empirical versus analytical friction terms in the shallow water approximation. Journal of Hydrology, 2015.

  11. Spatio-temporal Analysis of suspended sediment Concentration in the Yongjiang Estuary Based on GOCI (United States)

    Kang, Yanyan; Dong, Chuan


    The concentration and spatio-temporal variation of suspended sediment concentration in the estuary area are of great significance to the nearshore engineering, port construction and coastal evolution. Based on multi-period GOCI images and corresponding measured suspended sediment concentration (SSC) data, three inversion models (the linear regression model, the power exponent model and the neural network model) were established after rapid atmospheric correction. The results show that the absolute error of the three models is 0.20, 0.16 and 0.10kg/m3 respectively, and the relative errors are 38%, 23% and 18% respectively. The accuracy of the neural network (8-17-17-1) is the best. The SSC distribution diagrams in an ebb and flow cycle are obtained using this ANN model. The results show that with Yongjiang estuary for segmentation, the high concentration area is located in the north and the lower is in the south around Jintang Island deeper water area. When the tide rises, the water flow disturbs a large amount of sediment, and then the sediment concentration increases and high area high concentrations water body moves along the SE-NW. When the tide falls, flow rate decreases and the sediment concentration decreases. However, with the falling tide, the concentration of suspended sediment in the northern sea areas gradually increases, and is higher than 1kg/m3, and gradually moves along the NW-SE until to the estuary.

  12. Regional regression models of watershed suspended-sediment discharge for the eastern United States (United States)

    Roman, David C.; Vogel, Richard M.; Schwarz, Gregory E.


    Estimates of mean annual watershed sediment discharge, derived from long-term measurements of suspended-sediment concentration and streamflow, often are not available at locations of interest. The goal of this study was to develop multivariate regression models to enable prediction of mean annual suspended-sediment discharge from available basin characteristics useful for most ungaged river locations in the eastern United States. The models are based on long-term mean sediment discharge estimates and explanatory variables obtained from a combined dataset of 1201 US Geological Survey (USGS) stations derived from a SPAtially Referenced Regression on Watershed attributes (SPARROW) study and the Geospatial Attributes of Gages for Evaluating Streamflow (GAGES) database. The resulting regional regression models summarized for major US water resources regions 1–8, exhibited prediction R2 values ranging from 76.9% to 92.7% and corresponding average model prediction errors ranging from 56.5% to 124.3%. Results from cross-validation experiments suggest that a majority of the models will perform similarly to calibration runs. The 36-parameter regional regression models also outperformed a 16-parameter national SPARROW model of suspended-sediment discharge and indicate that mean annual sediment loads in the eastern United States generally correlates with a combination of basin area, land use patterns, seasonal precipitation, soil composition, hydrologic modification, and to a lesser extent, topography.

  13. Spatial distribution of soil erosion and suspended sediment ...

    Indian Academy of Sciences (India)

    1983), EPIC (Williams et al. 1984), WEPP (Near- ing et al. 1989), AGNPS (Young et al. 1989), ..... river cells, and the other represents the land cells, which is superimposed upon layers such as soil types, land ...... Ricker M C, Odhiambo B K and Church J M 2008 Spa- tial analysis of soil erosion and sediment fluxes: A paired.

  14. Laboratory and field measurements of upwelled radiance and reflectance spectra of suspended James River sediments near Hopewell, Virginia (United States)

    Whilock, C. H.; Witte, W. G.; Gurganus, E. A.; Usry, J. W.


    Spectral reflectance characteristics of suspended Bermuda Hundred and Bailey Bay bottom sediments taken from the Hopewell, Va., area were measured in the laboratory for water mixture total suspended solids concentrations between 4 and 173 parts per million. Field spectral reflectance measurements were made of the James River waters near Bermuda Hundred on two occasions. The results of these tests indicate that both Bermuda Hundred and Bailey Bay suspended sediments produce their strongest reflectance in the green and red regions of the spectrum.

  15. Toward multi-day-ahead forecasting of suspended sediment concentration using ensemble models. (United States)

    Alizadeh, Mohamad Javad; Jafari Nodoushan, Ehsan; Kalarestaghi, Naghi; Chau, Kwok Wing


    This study explores two ideas to made an improvement on the artificial neural network (ANN)-based models for suspended sediment forecasting in several time steps ahead. In this regard, both observed and forecasted time series are incorporated as input variables of the models when applied for more than one lead time. Secondly, least-square ensemble models employing multiple wavelet-ANN models are developed to increase the performance of the single model. For this purpose, different wavelet families are linked with the ANN model and performance of each model is evaluated using error measures. The Skagit River near Mount Vernon in Washington county is selected as the case study. The daily flow discharge and suspended sediment concentration (SSC) in the current day are considered as input variables to predict suspended sediment concentration in the next day. For more lead times, the input structure is updated by adding the forecast of SSC in the previous time step. Results of this study demonstrate that incorporating both observed and predicted variables in the input structure improves performance of conventional models in which those only employ observed time series as input variables. Moreover, ensemble model developed for each lead time outperforms the best single wavelet-ANN model which indicates superiority of the ensemble model over the other one. Findings of this study reveal that acceptable forecasts of daily suspended sediment concentration up to 3 days in advance can be achieved using the proposed methodology.

  16. Observations of suspended sediment from ADCP and OBS measurements in a mud-dominated environment

    NARCIS (Netherlands)

    Hoitink, A.J.F.; Hoekstra, P.


    The ability of a 1.2-MHz Acoustic Doppler Current Profiler (ADCP) to measure suspended sediment concentration (SSC) and particle size variation in a mud-dominated environment has been investigated. Experiments were conducted in the Bay of Banten, Indonesia, where clays and silts in the range of 3-55

  17. Delivery of suspended sediment and associated phosphorus and heavy metals to small rural Danish streams

    DEFF Research Database (Denmark)

    Laubel, A. R.

    The aim of this study is to examine delivery pathways for suspended sediment, and particulate phosphorus (P) and heavy metals from open rural areas to small Danish streams. A further aim is to quantify the contribution from different path-ways and source areas. Such studies are useful as a basis...

  18. Overview of selected surrogate technologies for high-temporal resolution suspended-sediment monitoring (United States)

    Gray, John R.; Gartner, Jeffrey W.


    Traditional methods for characterizing selected properties of suspended sediments in rivers are being augmented and in some cases replaced by cost-effective surrogate instruments and methods that produce a temporally dense time series of quantifiably accurate data for use primarily in sediment-flux computations. Turbidity is the most common such surrogate technology, and the first to be sanctioned by the U.S. Geological Survey for use in producing data used in concert with water-discharge data to compute sediment concentrations and fluxes for storage in the National Water Information System. Other technologies, including laser-diffraction, digital photo-optic, acoustic-attenuation and backscatter, and pressure-difference techniques are being evaluated for producing reliable sediment concentration and, in some cases, particle-size distribution data. Each technology addresses a niche for sediment monitoring. Their performances range from compelling to disappointing. Some of these technologies have the potential to revolutionize fluvial-sediment data collection, analysis, and availability.

  19. A 2-D process-based model for suspended sediment dynamics: A first step towards ecological modeling (United States)

    Achete, F. M.; van der Wegen, M.; Roelvink, D.; Jaffe, B.


    In estuaries suspended sediment concentration (SSC) is one of the most important contributors to turbidity, which influences habitat conditions and ecological functions of the system. Sediment dynamics differs depending on sediment supply and hydrodynamic forcing conditions that vary over space and over time. A robust sediment transport model is a first step in developing a chain of models enabling simulations of contaminants, phytoplankton and habitat conditions. This works aims to determine turbidity levels in the complex-geometry delta of the San Francisco estuary using a process-based approach (Delft3D Flexible Mesh software). Our approach includes a detailed calibration against measured SSC levels, a sensitivity analysis on model parameters and the determination of a yearly sediment budget as well as an assessment of model results in terms of turbidity levels for a single year, water year (WY) 2011. Model results show that our process-based approach is a valuable tool in assessing sediment dynamics and their related ecological parameters over a range of spatial and temporal scales. The model may act as the base model for a chain of ecological models assessing the impact of climate change and management scenarios. Here we present a modeling approach that, with limited data, produces reliable predictions and can be useful for estuaries without a large amount of processes data.

  20. A 2-D process-based model for suspended sediment dynamics: a first step towards ecological modeling (United States)

    Achete, F. M.; van der Wegen, M.; Roelvink, D.; Jaffe, B.


    In estuaries suspended sediment concentration (SSC) is one of the most important contributors to turbidity, which influences habitat conditions and ecological functions of the system. Sediment dynamics differs depending on sediment supply and hydrodynamic forcing conditions that vary over space and over time. A robust sediment transport model is a first step in developing a chain of models enabling simulations of contaminants, phytoplankton and habitat conditions. This works aims to determine turbidity levels in the complex-geometry delta of the San Francisco estuary using a process-based approach (Delft3D Flexible Mesh software). Our approach includes a detailed calibration against measured SSC levels, a sensitivity analysis on model parameters and the determination of a yearly sediment budget as well as an assessment of model results in terms of turbidity levels for a single year, water year (WY) 2011. Model results show that our process-based approach is a valuable tool in assessing sediment dynamics and their related ecological parameters over a range of spatial and temporal scales. The model may act as the base model for a chain of ecological models assessing the impact of climate change and management scenarios. Here we present a modeling approach that, with limited data, produces reliable predictions and can be useful for estuaries without a large amount of processes data.

  1. Characteristics of Suspended Sediment Loadings under Asian Summer Monsoon Climate Using the Hydrological Simulation Program-FORTRAN

    Directory of Open Access Journals (Sweden)

    Ji-Hong Jeon


    Full Text Available The extreme variation in the amount of annual precipitation and rainfall during single events is typical of the East Asian monsoon climate and may greatly influence the characteristics of the suspended sediment load. The turbidity in Lake Imha which is the eighth largest multipurpose dam in Korea has been the cause of major water quality problems for use as drinking water. The turbidity rose to 882 NTU, and it remained over 30 NTU continuously for 170 days during 2002, as the result of significant amounts of soil erosion from the watershed during the Asian monsoon typhoon. In this study, characteristics of suspended sediment loadings under the Asian summer monsoon climate was investigated by comparing the variation of yearly suspended sediment loads and the ratio of maximum suspended sediment loads in a single event to yearly suspended sediment load from Lake Imha watershed using the Hydrologic Simulation Program-FORTRAN (HSPF. The model calibration is performed according to the 2009–2010 events, and simulation results characterized suspended sediment loadings under the Asian summer monsoon climate for 2001–2010. Water sampling and flow rate measurements were performed every 4–6 h, and calibration was performed using hourly simulated sediment loads. The calibration results demonstrated good agreement with the observed data. The characteristics of suspended sediment loadings under the Asian summer monsoon climate are a high variance of the yearly suspended sediment load and a significant of amount of suspended sediment load during a single event influenced by the typhoon intensity. The maximum yearly suspended sediment load was 10 times higher than the minimum yearly value. About half of the yearly suspended sediment load was loaded with a single event under the Asian summer monsoon climate and the ratio of suspended sediment loads by a single event to total yearly loads ranged from 29% to 90%. Structural best management practices (BMPs to


    Directory of Open Access Journals (Sweden)

    Gabriela Adina MOROȘANU


    Full Text Available This paper aims to assess, from a statistical standpoint, the solid discharge at Corcova hydrometric station for the recent period between 1975 and 2012. The Corcova hydrometric station is located in the lowermost sector of the Coşuştea River Basin, at a distance of 2 km north-west from its confluence with Motru River. The usefulness of this study results from the endeavor to determine the years and months when the river presents an accumulation potential due to a higher transmission rate of the suspended sediment load. The statistical techniques applied in this study made use of the monthly, as well as the annual averages, minimum and maximum values of suspended sediment loads, in order to obtain the multiannual trends, seasonal and monthly differences. Thus, by using the Mann-Kendall test, the statistical distributions and frequency analysis, we could notice that the average solid discharge decreased in the last decades during the winter period, while between April and November, average solid discharge rose slightly, with a greater significance in May. Conversely, minimum solid discharge values were likely to indicate the years and months when the river’s solid intake was low, with the potential for bank erosion. The minimum values of suspended sediment loads showed little variation from year to year in all months, except for May and June, based on the influence of the peak liquid discharge on the potential erosion and sediment transport of Cosustea river. As a general conclusion, the most important aspects turned out to be the variations in April - June period, an interval well known for flash floods and high waters records, as well as for rapid changes in average, minimum and maximum solid flows.

  3. Storage and remobilization of suspended sediment in the lower amazon river of Brazil (United States)

    Meade, R.H.; Dunne, T.; Richey, J.E.; Santos, U.De. M.; Salati, E.


    In the lower Amazon River, suspended sediment is stored during rising stages of the river and resuspended during falling river stages. The storage and resuspension in the reach are related to the mean slope of the flood wave on the river surface; this slope is smaller during rising river stages than during falling stages. The pattern of storage and resuspension damps out the extreme values of high and low sediment discharge and tends to keep them near the mean value between 3.0 ?? 106 and 3.5 ?? 106 metric tons per day. Mean annual discharge of suspended sediment in the lower Amazon is between 1.1 ?? 109 and 1.3 ?? 109 metric tons per year.

  4. Comparison of turbidity to multi-frequency sideways-looking acoustic-Doppler data and suspended-sediment data in the Colorado River in Grand Canyon (United States)

    Voichick, Nicholas; Topping, David J.


    Water clarity is important to biologists when studying fish and other fluvial fauna and flora. Turbidity is an indicator of the cloudiness of water, or reduced water clarity, and is commonly measured using nephelometric sensors that record the scattering and absorption of light by particles in the water. Unfortunately, nephelometric sensors only operate over a narrow range of the conditions typically encountered in rivers dominated by suspended-sediment transport. For example, sediment inputs into the Colorado River in Grand Canyon caused by tributary floods often result in turbidity levels that exceed the maximum recording level of nephelometric turbidity sensors. The limited range of these sensors is one reason why acoustic Doppler profiler instrument data, not turbidity, has been used as a surrogate for suspended sediment concentration and load of the Colorado River in Grand Canyon. However, in addition to being an important water-quality parameter to biologists, turbidity of the Colorado River in Grand Canyon has been used to strengthen the suspended-sediment record through the process of turbidity-threshold sampling; high turbidity values trigger a pump sampler to collect samples of the river at critical times for gathering suspended-sediment data. Turbidity depends on several characteristics of suspended sediment including concentration, particle size, particle shape, color, and the refractive index of particles. In this paper, turbidity is compared with other parameters coupled to suspended sediment, namely suspended-silt and clay concentration and multifrequency acoustic attenuation. These data have been collected since 2005 at four stations with different sediment-supply characteristics on the Colorado River in Grand Canyon. These comparisons reveal that acoustic attenuation is a particularly useful parameter, because it is strongly related to turbidity and it can be measured by instruments that experience minimal fouling and record over the entire range

  5. Potential use of river suspended-sediment observations to evaluate the effects of seismic shaking on sediment yield (United States)

    Avşar, Ulaş


    It has been empirically proved that large earthquakes (M>6) trigger landslides and shattering of landscapes, which increase the sediment yield in drainage basins and hence sediment delivery to the rivers. Besides the historical records reporting eyewitness accounts of muddy rivers after earthquakes, this phenomenon was also supported by quantitative analyses on the suspended sediment load of rivers before and after the Chi-Chi Earthquake (Mw=7.6) in 1999 in Taiwan. Observations and understanding of this phenomenon is crucial to trace the sedimentological fingerprints of paleoearthquakes in marine and lacustrine sedimentary sequences. This study presents the evaluation of the publicly available river discharge and suspended-sediment concentration measurements to assess the possible effects of earthquakes on sediment yields in Turkey. For this purpose, measurements from 10 hydrometric stations are utilized, which are located near the epicentres of the 1998 Adana-Ceyhan Earthquake (Mw=6.2), the 1999 İzmit Earthquake (Mw=7.4) and the 1999 Düzce Earthquake (Mw=7.2). The dataset contains ca. 1600 measurements between 1991 and 2005. At only a few stations, anomalies in sediment concentration are observed immediately after the earthquakes. On the other hand, at most of the stations, the data through longer periods after the earthquakes (3-4 years) reveal slight increases in sediment concentration. The low temporal resolution of the measurements (every 20-30 days) limits the observation of possible sudden increase in sediment concentration immediately after the earthquakes. According to the preliminary results, sediment yield seems to be affected from seismic shaking. However, for more robust results, longer-term measurements with higher temporal resolution are required. The future study will focus on a quantitative evaluation and modelling on expected sediment yield after seismic shaking.

  6. Impacts of Suspended Sediment and Estuarine - Shelf Exchange Pathways on Shelf Ecosystem Dynamics in the Northern Gulf of Mexico (United States)

    Wiggert, J. D.; Pan, C.; Dinniman, M. S.; Lau, Y.; Fitzpatrick, P. J.; O'Brien, S. J.; Bouchard, C.; Quas, L. M.; Miles, T. N.; Cambazoglu, M. K.; Dykstra, S. L.; Dzwonkowski, B.; Jacobs, G. A.; Church, I.; Hofmann, E. E.


    A circulation model based on the Coupled-Ocean-Atmosphere-Wave-Sediment Transport (COAWST) Modeling System, with coupled biogeochemical and sediment transport modules, has been implemented for Mississippi Sound and the adjacent continental shelf region. The model has 400-m horizontal resolution, 24 vertical layers, and includes wetting/drying capability to resolve shallow inshore regions. The circulation model was spun-up using oceanographic initial and lateral boundary conditions provided by a 1-km resolution regional implementation of the Navy Coastal Ocean Model (NCOM) in the Gulf of Mexico. The biogeochemical module includes multiple size classes of phytoplankton, zooplankton and detritus, a fish larvae compartment, and explicitly tracks dissolved oxygen with benthic cycling interaction. The sediment transport model is implemented based on benthic mapping data that provides bottom sediment type distributions and spatio-temporal validation. A regionally specific atmospheric forcing product that provides improved spatial and temporal resolution, including diurnal sea breeze impacts, has been developed and applied. Model experiments focus on periods when comprehensive ship-based sampling was deployed by the CONCORDE (Consortium for Coastal River-Dominated Ecosystems) research program, which was established to investigate the complex fine-scale biological, chemical and physical interactions in a marine system controlled by pulsed-river plume dynamics. Biophysical interactions and biogeochemical variability associated with estuarine - shelf exchanges between nearshore lagoonal estuarine waters and the continental shelf revealed by the model provide new insight into how seasonal variation of hydrological forcing conditions influence ecological and biogeochemical processes in the highly productive Northern Gulf region. Application of the COAWST-based model system with and without inclusion of the sediment transport module demonstrates how suspended sediment in the

  7. Suspended sediment load in northwestern South America (Colombia): A new view on variability and fluxes into the Caribbean Sea (United States)

    Restrepo López, Juan Camilo; Orejarena R, Andrés F.; Torregroza, Ana Carolina


    Monthly averaged suspended sediment load data from seven rivers in northern Colombia (Caribbean alluvial plain) draining into the Caribbean Sea were analyzed to quantify magnitudes, estimate long-term trends, and evaluate variability patterns of suspended sediment load. Collectively these rivers deliver an average of around 146.3 × 106 t yr-1 of suspended sediments to the Colombian Caribbean coast. The largest sediment supply is provided by the Magdalena River, with a mean suspended sediment load of 142.6 × 106 t yr-1, or 38% of the total fluvial discharge estimated for the whole Caribbean littoral zone. Between 2000 and 2010, the annual suspended sediment load of these rivers increased by as much as 36%. Wavelet spectral analyses identified periods of intense variability between 1987-1990 and 1994-2002, where major oscillation processes appeared simultaneously. The semi-annual, annual and quasi-decadal bands are the main factors controlling suspended sediment load variability in fluvial systems, whereas the quasi-biennial and interannual bands constitute second-order sources of variability. The climatic and oceanographic drivers of the oscillations identified through wavelet spectral analyses define a signal of medium-long-term variability for the suspended sediment load, while the physiographic and environmental characteristics of the basins determine their ability to magnify, attenuate or modify this signal.

  8. Estimating concentrations of fine-grained and total suspended sediment from close-range remote sensing imagery (United States)

    Mosbrucker, Adam; Spicer, Kurt R.; Christianson, Tami; Uhrich, Mark A.


    Fluvial sediment, a vital surface water resource, is hazardous in excess. Suspended sediment, the most prevalent source of impairment of river systems, can adversely affect flood control, navigation, fisheries and aquatic ecosystems, recreation, and water supply (e.g., Rasmussen et al., 2009; Qu, 2014). Monitoring programs typically focus on suspended-sediment concentration (SSC) and discharge (SSQ). These time-series data are used to study changes to basin hydrology, geomorphology, and ecology caused by disturbances. The U.S. Geological Survey (USGS) has traditionally used physical sediment sample-based methods (Edwards and Glysson, 1999; Nolan et al., 2005; Gray et al., 2008) to compute SSC and SSQ from continuous streamflow data using a sediment transport-curve (e.g., Walling, 1977) or hydrologic interpretation (Porterfield, 1972). Accuracy of these data is typically constrained by the resources required to collect and analyze intermittent physical samples. Quantifying SSC using continuous instream turbidity is rapidly becoming common practice among sediment monitoring programs. Estimations of SSC and SSQ are modeled from linear regression analysis of concurrent turbidity and physical samples. Sediment-surrogate technologies such as turbidity promise near real-time information, increased accuracy, and reduced cost compared to traditional physical sample-based methods (Walling, 1977; Uhrich and Bragg, 2003; Gray and Gartner, 2009; Rasmussen et al., 2009; Landers et al., 2012; Landers and Sturm, 2013; Uhrich et al., 2014). Statistical comparisons among SSQ computation methods show that turbidity-SSC regression models can have much less uncertainty than streamflow-based sediment transport-curves or hydrologic interpretation (Walling, 1977; Lewis, 1996; Glysson et al., 2001; Lee et al., 2008). However, computation of SSC and SSQ records from continuous instream turbidity data is not without challenges; some of these include environmental fouling, calibration, and

  9. Modeling sediment transport with an integrated view of the biofilm effects (United States)

    Fang, H. W.; Lai, H. J.; Cheng, W.; Huang, L.; He, G. J.


    Most natural sediment is invariably covered by biofilms in reservoirs and lakes, which have significant influence on bed form dynamics and sediment transport, and also play a crucial role in natural river evolution, pollutant transport, and habitat changes. However, most models for sediment transport are based on experiments using clean sediments without biological materials. In this study, a three-dimensional mathematical model of hydrodynamics and sediment transport is presented with a comprehensive consideration of the biofilm effects. The changes of the bed resistance mainly due to the different bed form dynamics of the biofilm-coated sediment (biosediment), which affect the hydrodynamic characteristics, are considered. Moreover, the variations of parameters related to sediment transport after the biofilm growth are integrated, including the significant changes of the incipient velocity, settling velocity, reference concentration, and equilibrium bed load transport rate. The proposed model is applied to evaluate the effects of biofilms on the hydrodynamic characteristics and sediment transport in laboratory experiments. Results indicate that the mean velocity increases after the biofilm growth, and the turbulence intensity near the river bed decreases under the same flow condition. Meanwhile, biofilm inhibits sediment from moving independently. Thus, the moderate erosion is observed for biosediment resulting in smaller suspended sediment concentrations. The proposed model can reasonably reflect these sediment transport characteristics with biofilms, and the approach to integration of the biological impact could also be used in other modeling of sediment transport, which can be further applied to provide references for the integrated management of natural aqueous systems.

  10. Sediment supply versus local hydraulic controls on sediment transport and storage in a river with large sediment loads (United States)

    Dean, David J.; Topping, David J.; Schmidt, John C.; Griffiths, Ronald E.; Sabol, Thomas A.


    The Rio Grande in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, undergoes rapid geomorphic changes as a result of its large sediment supply and variable hydrology; thus, it is a useful natural laboratory to investigate the relative importance of flow strength and sediment supply in controlling alluvial channel change. We analyzed a suite of sediment transport and geomorphic data to determine the cumulative influence of different flood types on changing channel form. In this study, physically based analyses suggest that channel change in the Rio Grande is controlled by both changes in flow strength and sediment supply over different spatial and temporal scales. Channel narrowing is primarily caused by substantial deposition of sediment supplied to the Rio Grande during tributary-sourced flash floods. Tributary floods have large suspended-sediment concentrations, occur for short durations, and attenuate rapidly downstream in the Rio Grande, depositing much of their sediment in downstream reaches. Long-duration floods on the mainstem have the capacity to enlarge the Rio Grande, and these floods, released from upstream dams, can either erode or deposit sediment in the Rio Grande depending upon the antecedent in-channel sediment supply and the magnitude and duration of the flood. Geomorphic and sediment transport analyses show that the locations and rates of sand erosion and deposition during long-duration floods are most strongly controlled by spatial changes in flow strength, largely through changes in channel slope. However, spatial differences in the in-channel sediment supply regulate sediment evacuation or accumulation over time in long reaches (greater than a kilometer).

  11. Quantifying suspended sediment sources during flood events in headwater catchments using diffuse reflectance spectroscopy (United States)

    Legout, Cédric; Poulenard, Jérôme; Nemery, Julien; Navratil, Oldrich; Grangeon, Thomas; Evrard, Olivier; Esteves, Michel


    Increasing the understanding of the hydro-sedimentary dynamics at the catchment scale requires data on the origin of suspended sediments in addition to the classical measurements of suspended sediment concentrations and discharge. In mountainous environments the extremely high spatial and temporal variability of suspended sediment fluxes suggests that the proportions of suspended sediment sources transiting at outlets may also exhibit strong variations during flood events. However, conventional fingerprinting techniques based on geochemical and radionuclide measurements are time-consuming and rather expensive. They constitute a major limitation to conduct routine characterisation of the source of suspended sediment transiting at outlets that would require the analysis of a large number of samples. We investigated how visible or infrared diffuse reflectance spectroscopy coupled with partial least squares chemometrics techniques could be used to predict the proportion of source material in suspended sediment samples and how it could help understanding the hydro-sedimentary processes occurring during floods. The studied catchment is located in the southern French Alps, draining an area of 22-km². It is composed of black marls, limestones, molasses, undifferentiated deposits and gypsum. Forty-eight source material samples were collected in badlands areas and 328 suspended sediment samples were collected at the outlet during 23 flood events. Spectroscopic measurements were carried out on dried samples. Given that the erosion processes are particle size selective, five size fractions of source material were measured in order to assess the potential alteration of the signatures. As the biogeochemical processes occurring in the river such as iron oxidation could also affect the signatures, source materials that were immersed in the river for durations ranging from 1 day to 9 weeks were analysed. Finally, partial least-squares regression models were constructed on 81

  12. A 2D hydro-morphodynamic modelling approach for predicting suspended sediment propagation and related heavy metal contamination in floodplains: a sensitivity analysis (United States)

    Hostache, Renaud; Hissler, Christophe; Matgen, Patrick; Guignard, Cédric; Bates, Paul


    Recent years have seen a growing awareness for the central role that fine sediment loads play in transport and diffusion of pollutants by rivers and streams. Suspended sediment can potentially carry important amounts of nutrients and contaminants, such as trace metals among which some are recognized as Potential Harmful Elements (PHE). These threaten water quality in rivers and wetlands and soil quality in floodplains. Currently, many studies focusing on sediment transport modelling deal with marine and estuarine areas. Some studies evaluate sediment transport at basin scales and often evaluate yearly sediment fluxes using hydrologic and simplified hydraulic models. Some more theoretical studies develop and improve numerical models on the basis of physical model experiments. As a matter of fact, sediment transport modelling in small rivers at reach/floodplain scale is a rather new research field. In this study, we aim at simulating sediment transport at the floodplain scale and the single flood event scale in order to predict sediment spreading on alluvial soils. This simulation will help for the estimation of the potential pollution of soils due to the transport of PHEs by suspended sediments. The model is based upon the Telemac hydro-informatic system (i.e. dynamical coupling of Telemac-2D and Sysiphe). As empirical and semi-empirical parameters need to be calibrated for such a modelling exercise, a sensitivity analysis is proposed. In parallel to the modelling exercise, an extensive hydrological/geochemical database has been set up for two flood events. The most sensitive parameters were found to be the hydraulic friction coefficient and the sediment particle settling velocity in water. Using the two monitored hydrological events for calibration and validation, it was found that the model is able to satisfyingly predict suspended sediment and dissolved pollutant transport in the river channel. In addition, a qualitative comparison between simulated sediment

  13. Assessment of selected contaminants in streambed- and suspended-sediment samples collected in Bexar County, Texas, 2007-09 (United States)

    Wilson, Jennifer T.


    Elevated concentrations of sediment-associated contaminants are typically associated with urban areas such as San Antonio, Texas, in Bexar County, the seventh most populous city in the United States. This report describes an assessment of selected sediment-associated contaminants in samples collected in Bexar County from sites on the following streams: Medio Creek, Medina River, Elm Creek, Martinez Creek, Chupaderas Creek, Leon Creek, Salado Creek, and San Antonio River. During 2007-09, the U.S. Geological Survey periodically collected surficial streambed-sediment samples during base flow and suspended-sediment (large-volume suspended-sediment) samples from selected streams during stormwater runoff. All sediment samples were analyzed for major and trace elements and for organic compounds including halogenated organic compounds and polycyclic aromatic hydrocarbons (PAHs). Selected contaminants in streambed and suspended sediments in watersheds of the eight major streams in Bexar County were assessed by using a variety of methods—observations of occurrence and distribution, comparison to sediment-quality guidelines and data from previous studies, statistical analyses, and source indicators. Trace elements concentrations were low compared to the consensus-based sediment-quality guidelines threshold effect concentration (TEC) and probable effect concentration (PEC). Trace element concentrations were greater than the TEC in 28 percent of the samples and greater than the PEC in 1.5 percent of the samples. Chromium concentrations exceeded sediment-quality guidelines more frequently than concentrations of any other constituents analyzed in this study (greater than the TEC in 69 percent of samples and greater than the PEC in 8 percent of samples). Mean trace element concentrations generally are lower in Bexar County samples compared to concentrations in samples collected during previous studies in the Austin and Fort Worth, Texas, areas, but considering the relatively

  14. Interpreting the suspended sediment dynamics in a mesoscale river basin of Central Mexico using a nested watershed approach (United States)

    Duvert, C.; Némery, J.; Gratiot, N.; Prat, C.; Collet, L.; Esteves, M.


    The Cointzio river basin is located within the Mexican Transvolcanic Belt, in the Michoacán state. Land-use changes undergone over last decades lead to significant erosion processes, though affecting limited areas of the basin. Apart from generating a minor depletion of arable land by incising small headwater areas, this important sediment delivery contributed to siltation in the reservoir of Cointzio, situated right downstream of the basin. During 2009 rainy season, a detailed monitoring of water and sediment fluxes was undertaken in three headwater catchments located within the Cointzio basin (Huertitas, Potrerillos and La Cortina, respectively 2.5, 9.3 and 12.0 km2), as well as at the outlet of the main river basin (station of Santiago Undameo, 627 km2). Preliminary tests realized in 2008 underlined the necessity of carrying out a high-frequency monitoring strategy to assess the sediment dynamics in the basins of this region. In each site, water discharge time-series were obtained from continuous water-level measurements (5-min time-step), and stage-discharge rating curves. At the river basin outlet, Suspended Sediment Concentration (SSC) was estimated every 10 minutes through turbidity measurements calibrated with data from automatic sampling. In the three sub-catchments, SSC time-series were calculated using stage-triggered automatic water samplers. The three upland areas monitored in our study present distinct landforms, morphology and soil types. La Cortina is underlain by andisols, rich in organic matter and with an excellent microstructure under wet conditions. Huertitas and Potrerillos both present a severely gullied landscape, bare and highly susceptible to water erosion in degraded areas. As a result, suspended sediment yields in 2009 were expectedly much higher in these two sub-catchments (≈320 in Huertitas and ≈270 in Potrerillos) than in La Cortina (≈40 The total suspended sediment export was approximately of 30

  15. Study of glyphosate transport through suspended particulate matter (United States)

    Amiot, Audrey; Landry, David; Jadas-Hécart, Alain; La Jeunesse, Isabelle; Sourice, Stéphane; Ballouche, Aziz


    complete (95% in 2 min). (ii) Kd obtained on the erodible fraction are two times higher than on 2 mm sieved soils. (iii) Desorption showed that glyphosate is desorbed from the erodible fraction at 40% after 25 desorptions. The aim of this study was to show the potential transport of glyphosate through suspended particulate matter. The adsorption on the erodible fraction argued to a significant transport potential of glyphosate on this fraction. The desorption of glyphosate from the erodible water fraction have revealed that the adsorption of glyphosate is reversible but it is much slower. These results demonstrate that glyphosate may be stored on the erodible fraction and be transported by these fractions. Keywords: Adsorption, Desorption, Glyphosate, Suspended Solids, Erosion.

  16. Measurement of light attenuation extends the application of suspended sediment monitoring in rivers

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    A. O. Hughes


    Full Text Available Turbidity is often monitored continuously as a proxy for suspended sediment in catchment sediment load studies, but is less often applied to measuring optical ‘loads’ as they affect water quality in downstream waters. We added measurements of visual clarity, from which light (beam attenuation can be estimated, to auto-sampler monitoring over storm events in tributary rivers of the Kaipara Harbour, a large barrier enclosed estuary complex in northern New Zealand. This paper presents, for the first time, evidence of the mutual relationships between turbidity, total suspended sediment (TSS, and visual clarity, from water samples collected under event flow conditions. The mutual relationships between turbidity, TSS and visual clarity for our monitoring sites were fairly close over about three orders of magnitude (TSS ranging from about 1–1000 mg L−1. Our results show that visual clarity (and hence light attenuation can be predicted from turbidity, at least as precisely as more traditional predictions of TSS from turbidity. The estimation of light attenuation and corresponding load estimates from visual clarity measurements, for relatively little marginal extra effort, extends the environmental relevance and application of suspended sediment monitoring.

  17. Total nitrogen and suspended-sediment loads and identification of suspended-sediment sources in the Laurel Hill Creek watershed, Somerset County, Pennsylvania, water years 2010-11 (United States)

    Sloto, Ronald A.; Gellis, Allen C.; Galeone, Daniel G.


    Laurel Hill Creek is a watershed of 125 square miles located mostly in Somerset County, Pennsylvania, with small areas extending into Fayette and Westmoreland Counties. The upper part of the watershed is on the Pennsylvania Department of Environmental Protection 303(d) list of impaired streams because of siltation, nutrients, and low dissolved oxygen concentrations. The objectives of this study were to (1) estimate the annual sediment load, (2) estimate the annual nitrogen load, and (3) identify the major sources of fine-grained sediment using the sediment-fingerprinting approach. This study by the U.S. Geological Survey (USGS) was done in cooperation with the Somerset County Conservation District. Discharge, suspended-sediment, and nutrient data were collected at two streamflow-gaging stations—Laurel Hill Creek near Bakersville, Pa., (station 03079600) and Laurel Hill Creek at Ursina, Pa., (station 03080000)—and one ungaged stream site, Laurel Hill Creek below Laurel Hill Creek Lake at Trent (station 03079655). Concentrations of nutrients generally were low. Concentrations of ammonia were less than 0.2 milligrams per liter (mg/L), and concentrations of phosphorus were less than 0.3 mg/L. Most concentrations of phosphorus were less than the detection limit of 0.02 mg/L. Most water samples had concentrations of nitrate plus nitrite less than 1.0 mg/L. At the Bakersville station, concentrations of total nitrogen ranged from 0.63 to 1.3 mg/L in base-flow samples and from 0.57 to 1.5 mg/L in storm composite samples. Median concentrations were 0.88 mg/L in base-flow samples and 1.2 mg/L in storm composite samples. At the Ursina station, concentrations of total nitrogen ranged from 0.25 to 0.92 mg/L in base-flow samples; the median concentration was 0.57 mg/L. The estimated total nitrogen load at the Bakersville station was 262 pounds (lb) for 11 months of the 2010 water year (November 2009 to September 2010) and 266 lb for the 2011 water year. Most of the total

  18. Suspended-sediment trapping in the tidal reach of an estuarine tributary channel (United States)

    Downing-Kunz, Maureen; Schoellhamer, David H.


    Evidence of decreasing sediment supply to estuaries and coastal oceans worldwide illustrates the need for accurate and updated estimates. In the San Francisco Estuary (Estuary), recent research suggests a decrease in supply from its largest tributaries, implying the increasing role of smaller, local tributaries in sediment supply to this estuary. Common techniques for estimating supply from tributaries are based on gages located above head of tide, which do not account for trapping processes within the tidal reach. We investigated the effect of a tidal reach on suspended-sediment discharge for Corte Madera Creek, a small tributary of the Estuary. Discharge of water (Q) and suspended-sediment (SSD) were observed for 3 years at two locations along the creek: upstream of tidal influence and at the mouth. Comparison of upstream and mouth gages showed nearly 50 % trapping of upstream SSD input within the tidal reach over this period. At the storm time scale, suspended-sediment trapping efficiency varied greatly (range −31 to 93 %); storms were classified as low- or high-yield based on upstream SSD. As upstream peak Q increased, high-yield storms exhibited significantly decreased trapping. Tidal conditions at the mouth—ebb duration and peak ebb velocity—during storms had a minor effect on sediment trapping, suggesting fluvial processes dominate. Comparison of characteristic fluvial and tidal discharges at the storm time scale demonstrated longitudinal differences in the regulating process for SSD. These results suggest that SSD from gages situated above head of tide overestimate sediment supply to the open waters beyond tributary mouths and thus trapping processes within the tidal reach should be considered.

  19. How Much Water and Suspended Sediment Does a Large Tropical Island Shed During a Major Hurricane? Hydrologic and Geomorphologic Effects of Hurricane Georges, September 1998, Puerto Rico (United States)

    Larsen, M. C.; Webb, R. M.; Warne, A. G.


    On September 21-22 1998, Hurricane Georges, a category-3 hurricane on the Saffir-Simpson scale, produced heavy rainfall, flooding, and landslides in the mountains and coastal plains of Puerto Rico. In general, rainfall, runoff, and sediment yield vary across the 8,711 square kilometer island of Puerto Rico because of an orographic barrier, the Cordillera Central. Mean annual runoff for the island is estimated to be 910 mm (equal to 8 billion cubic meters), which is about 57 percent of mean annual precipitation: 1,600 mm (14 billion cubic meters). Mean annual suspended-sediment discharge from Puerto Rico into surrounding coastal waters is estimated at 5.9 (+/- 3.2) million metric tonnes. The largely mountainous watersheds of the island are small (tens to hundreds of square kilometers), channel gradients are steep, and most stream valleys tend to be well-incised and narrow. Major rainstorms are intense but brief. As a consequence, flood waters rise rapidly (minutes to tens of minutes) with peak discharges several orders of magnitude above base discharge, and flood waters recede quickly (hours). Major storms transport a substantial portion of suspended sediment from uplands to the coast, based on data from a set of nine suspended-sediment monitoring stations representative of typical conditions in Puerto Rico. During Hurricane Georges, U. S. Geological Survey and National Weather Service rain-gage networks recorded 2-day rainfalls that ranged from about 100 mm to 630 mm (average was 300 mm, equal to about 2.6 billion cubic meters of water). Many streams rose more than 5 meters, resulting in severe flooding in northern, southwestern, and western watersheds. Landslides dissected roads and isolated communities on both the northern and southern slopes of the Cordillera Central. More than twice the mean annual discharge flowed from some watersheds (approximately 1 billion cubic meters of water for the entire island) carrying with it one to six times the mean annual load of

  20. Suspended sediment concentration–discharge relationships in the (sub- humid Ethiopian highlands

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    C. D. Guzman


    Full Text Available Loss of top soil and subsequent filling up of reservoirs in much of the lands with variable relief in developing countries degrades environmental resources necessary for subsistence. In the Ethiopia highlands, sediment mobilization from rain-fed agricultural fields is one of the leading factors causing land degradation. Sediment rating curves, produced from long-term sediment concentration and discharge data, attempt to predict suspended sediment concentration variations, which exhibit a distinct shift with the progression of the rainy season. In this paper, we calculate sediment rating curves and examine this shift in concentration for three watersheds in which rain-fed agriculture is practiced to differing extents. High sediment concentrations with low flows are found at the beginning of the rainy season of the semi-monsoonal climate, while high flows and low sediment concentrations occur at the end of the rainy season. Results show that a reasonably unique set of rating curves were obtained by separating biweekly data into early, mid, and late rainfall periods and by making adjustments for the ratio of plowed cropland. The shift from high to low concentrations suggests that diminishing sediment supply and dilution from greater base flow during the end of the rainfall period play important roles in characterizing changing sediment concentrations during the rainy season.

  1. Modeling nearshore dispersal of river-derived multi-class suspended sediments and radionuclides during a flood event around the mouth of Niida River, Fukushima, Japan (United States)

    Uchiyama, Y.; Yamanishi, T.; Iwasaki, T.; Shimizu, Y.; Tsumune, D.; Misumi, K.; Onda, Y.


    A quadruple nested synoptic oceanic downscale modeling based on ROMS was carried out to investigate hydrodynamics, multi-class non-cohesive sediment transport and associated dispersal of suspended radionuclides (cesium-137; 137Cs) originated from the nuclear accident occurred at the Fukushima Dai-ichi Power Plant in March 2011. The innermost model has horizontal grid resolution of 50 m to marginally resolve the topography around the river mouth including the surf zone. The model is forced by the JCOPE2 oceanic reanalysis as the outermost boundary conditions, the GPV-MSM atmospheric reanalysis, and an in-house SWAN spectral wave hindcast embedded in the operational GPV-CWM wave reanalysis. A particular attention is paid to nearshore behaviors and inventory of the nuclides attached to terrestrial minerals with grain sizes ranging from 5 to 79 micrometers that have been occasionally discharged out to the coastal ocean through hydrological processes within the river basin even after several years since the accident. We examine oceanic dispersal of sediment and suspended 137Cs influxes from Niida River, Fukushima, evaluated with the iRIC-Nays2DH river model. Our focus is on the first flood event in late May of 2011 after the accident. Alongshore asymmetry in transport of suspended sediments and 137Cs is exhibited, comprising storm-driven southward transport confined in the shallow area due to shoreward Ekman transport associated with strong northerly wind, followed by northwestward wide-spread transport under mild southerly wind condition. About 70 % of the Niida River-derived suspended 137Cs remains near the mouth for 20 days after the flood event. Nevertheless, our model results as well as an observation suggest that the area is dominated by erosion as for high bed shear stress all the time, thus suspended radionuclides are redistributed to dissipate away in long term.

  2. The influence of a semi-arid sub-catchment on suspended sediments in the Mara River, Kenya. (United States)

    Dutton, Christopher L; Subalusky, Amanda L; Anisfeld, Shimon C; Njoroge, Laban; Rosi, Emma J; Post, David M


    The Mara River Basin in East Africa is a trans-boundary basin of international significance experiencing excessive levels of sediment loads. Sediment levels in this river are extremely high (turbidities as high as 6,000 NTU) and appear to be increasing over time. Large wildlife populations, unregulated livestock grazing, and agricultural land conversion are all potential factors increasing sediment loads in the semi-arid portion of the basin. The basin is well-known for its annual wildebeest (Connochaetes taurinus) migration of approximately 1.3 million individuals, but it also has a growing population of hippopotami (Hippopotamus amphibius), which reside within the river and may contribute to the flux of suspended sediments. We used in situ pressure transducers and turbidity sensors to quantify the sediment flux at two sites for the Mara River and investigate the origin of riverine suspended sediment. We found that the combined Middle Mara-Talek catchment, a relatively flat but semi-arid region with large populations of wildlife and domestic cattle, is responsible for 2/3 of the sediment flux. The sediment yield from the combined Middle Mara-Talek catchment is approximately the same as the headwaters, despite receiving less rainfall. There was high monthly variability in suspended sediment fluxes. Although hippopotamus pools are not a major source of suspended sediments under baseflow, they do contribute to short-term variability in suspended sediments. This research identified sources of suspended sediments in the Mara River and important regions of the catchment to target for conservation, and suggests hippopotami may influence riverine sediment dynamics.

  3. Decreasing Suspended Sediment Concentrations and Loads in the Lower Mississippi and Atchafalaya Rivers, 1980 through 2015 (United States)

    Mize, S.


    Suspended-sediment concentration (SSC) and suspended-sediment load (SSL) trends were determined for the lower portion of the Mississippi and the Atchafalaya Rivers from 1980 through 2015 using suspended-sediment data from two stations in the U.S. Geological Survey's National Stream Quality Accounting Network. The Weighted Regressions on Time, Season and Discharge (WRTDS) model was used to derive estimates of SSC and SSL; to relate SSC and SSL with season and discharge; and to identify trends. Use of the WRTDS model reduces uncertainty in suspended-sediment concentrations related to variable streamflow conditions. Flow-normalized SSCs in each river were similar, and decreased by about half from 1980 through 2015 - from about 260 milligrams per liter (mg/L) to 130 mg/L. The annual SSL in both rivers combined decreased from about 200 million metric tons per year (MT/y) to about 100 MT/y over the same time period. SSC and SSL declined in both rivers from 1980 through 2015, although more slowly from 2005 through 2015 and these declines show signs of stabilizing. SSC and streamflow differed in an important way between the two rivers. SSC increased as streamflow increased for the entire range of observed streamflow in the Atchafalaya River. In contrast, in the Mississippi River, SSC followed the same increasing pattern during low and moderate streamflow, but concentrations decreased during the highest streamflow events which tended to occur between January and July. Since much of the water flowing in the Atchafalaya originates from the Mississippi River, the difference suggests a within-basin source of suspended sediment for the Atchafalaya River that is absent in the lower Mississippi River. Accurate estimates of the SSC and SSL available in each river are crucial for understanding how effective diversions of river water into adjacent estuaries will be in sustaining these wetlands. Our study demonstrates that there might be far less sediment available than previously

  4. Using high-resolution suspended-sediment measurements to infer changes in the topographic distribution and grain size of bed sediment in the Colorado River downstream from Glen Canyon Dam (United States)

    Topping, D. J.; Rubin, D. M.; Melis, T. S.; Wright, S. A.


    Eddy sandbars and other sandy deposits in and along the Colorado River in Grand Canyon National Park (GCNP) were an integral part of the pre-dam riverscape, and are still important for habitat, protection of archeological sites, and recreation. Recent work has shown that eddy bars are dynamic landforms and represent the bulk of the ecosystem's sand reserves. These deposits began eroding following the 1963 closure of Glen Canyon Dam that reduced the supply of sand at the upstream boundary of GCNP by about 94% and are still eroding today. Sand transport in the post-dam river is limited by episodic resupply from tributaries, and is equally regulated by the discharge of water and short-term changes in the grain size of sand available for transport (Rubin and Topping, WRR, 2001). During tributary floods, sand on the bed of the Colorado River fines; this causes the suspended sand to fine and the suspended-sand concentration to increase even when the discharge of water remains constant. Subsequently, the bed is winnowed of finer sand, the suspended sand coarsens, and the suspended-sand concentration decreases independently of discharge. This prohibits the computation of sand-transport rates in the Colorado River using stable relations between water discharge and sand transport (i.e., sediment rating curves) and requires a more continuous method for measuring sand transport. To monitor suspended sediment at higher (i.e., 15-minute) resolutions, we began testing a laser-acoustic system at four locations along the Colorado River in Grand Canyon in August 2002. Because they are much easier to acquire, the high-resolution suspended-sediment datasets collected using the laser-acoustic systems greatly outnumber (by >5 orders of magnitude) direct grain-size measurements of the upstream bed sediment. Furthermore, suspension processes effectively provide an average "sample" of the bed sediment on the perimeter of the upstream channel and the underwater portions of the banks and

  5. Impacts of large dams on the complexity of suspended sediment dynamics in the Yangtze River (United States)

    Wang, Yuankun; Rhoads, Bruce L.; Wang, Dong; Wu, Jichun; Zhang, Xiao


    The Yangtze River is one of the largest and most important rivers in the world. Over the past several decades, the natural sediment regime of the Yangtze River has been altered by the construction of dams. This paper uses multi-scale entropy analysis to ascertain the impacts of large dams on the complexity of high-frequency suspended sediment dynamics in the Yangtze River system, especially after impoundment of the Three Gorges Dam (TGD). In this study, the complexity of sediment dynamics is quantified by framing it within the context of entropy analysis of time series. Data on daily sediment loads for four stations located in the mainstem are analyzed for the past 60 years. The results indicate that dam construction has reduced the complexity of short-term (1-30 days) variation in sediment dynamics near the structures, but that complexity has actually increased farther downstream. This spatial pattern seems to reflect a filtering effect of the dams on the on the temporal pattern of sediment loads as well as decreased longitudinal connectivity of sediment transfer through the river system, resulting in downstream enhancement of the influence of local sediment inputs by tributaries on sediment dynamics. The TGD has had a substantial impact on the complexity of sediment series in the mainstem of the Yangtze River, especially after it became fully operational. This enhanced impact is attributed to the high trapping efficiency of this dam and its associated large reservoir. The sediment dynamics "signal" becomes more spatially variable after dam construction. This study demonstrates the spatial influence of dams on the high-frequency temporal complexity of sediment regimes and provides valuable information that can be used to guide environmental conservation of the Yangtze River.

  6. Suspended sediment and phosphorus budget and trophic status of Bukit Merah Reservoir, Perak, Malaysia

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    Najib Sumayyah Aimi Mohd


    Full Text Available Bukit Merah Reservoir (BMR is one of the 51 impoundments in Malaysia. BMR is the oldest reservoir built in the early 1900s originally to store water for irrigation, but nowadays its functions include also flood control and water supply. Nowadays, it is threatened by land use change in the upper catchments and surrounding activities, which feeding eroded material and chemicals into the reservoir. Suspended sediment, as well as, nutrient fluxes into BMR are becoming an increasing threat to the reservoir, as its sedimentation and eutrophication accelerate. This paper discusses our study on the BMR carried out between March 2008 and April 2009 to assess the water quality status, and to determine the sediment and Total Phosphorus (TP influx into the south pool lake. An estimated amount of suspended sediment fluxes of about 2,900 t year−1 came from the north pool lake (18% and 12,900 t year−1 from the main Kurau River inlet (82% of the total input to the BMR. Of these total sediment input (nearly 15,800 t about 5,600 t (36% of the total sediment influx was trapped in the BMR. TP influx was about 18.8 t year−1 and about 7 t (37% was trapped in the reservoir. The amount sediment and TP stored in the BMR affect the water quality of the lake, therefore the mean trophic state of the lake is eutrophic (TSI of 54.4 related to high productivity. Increasing sediment input into the reservoir has affected the reservoir volume and frequent flooding down-stream of the reservoir during rainy seasons, while eutrophication has caused the lake water quality deterioration.

  7. Frequency Selection for Multi-frequency Acoustic Measurement of Suspended Sediment (United States)

    Chen, X.; HO, H.; Fu, X.


    Multi-frequency acoustic measurement of suspended sediment has found successful applications in marine and fluvial environments. Difficult challenges remain in regard to improving its effectiveness and efficiency when applied to high concentrations and wide size distributions in rivers. We performed a multi-frequency acoustic scattering experiment in a cylindrical tank with a suspension of natural sands. The sands range from 50 to 600 μm in diameter with a lognormal size distribution. The bulk concentration of suspended sediment varied from 1.0 to 12.0 g/L. We found that the commonly used linear relationship between the intensity of acoustic backscatter and suspended sediment concentration holds only at sufficiently low concentrations, for instance below 3.0 g/L. It fails at a critical value of concentration that depends on measurement frequency and the distance between the transducer and the target point. Instead, an exponential relationship was found to work satisfactorily throughout the entire range of concentration. The coefficient and exponent of the exponential function changed, however, with the measuring frequency and distance. Considering the increased complexity of inverting the concentration values when an exponential relationship prevails, we further analyzed the relationship between measurement error and measuring frequency. It was also found that the inversion error may be effectively controlled within 5% if the frequency is properly set. Compared with concentration, grain size was found to heavily affect the selection of optimum frequency. A regression relationship for optimum frequency versus grain size was developed based on the experimental results.

  8. Spatial and temporal variability of suspended sediment yield in the Kamchatka Krai, Russian Federation

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    L. Kuksina


    Full Text Available Research into the spatial and temporal variability of suspended sediment flux (SSF, t year−1 has been conducted for rivers in the Kamchatka Krai (in the far east of the Russian Federation. The study of long-term fluctuations in SSF was based on difference-integral curve analysis. Most of the rivers in the region are characterized by two relatively long-term trends in SSF; increases from the late 1970s to the early 1980s, followed by a subsequent decline. Kamchatka was divided into regions based on similar conditions of specific suspended sediment yield (SSSY, t km−2 year−1 followed by a determination of the various factors controlling it. New maps of suspended sediment concentration (SSC, mg L−1 and SSSY for Kamchatka also were constructed and, based on this study, there currently appear to be 18 SSC and 13 SSSY regions, as opposed to 4 and 2 regions, respectively, as had been determined in the 1970s. The influence of volcanoes on SSF can be substantial, and can increase up to 5-fold after eruptions; SSC can reach 6∙105 mg L−1 in rivers draining the flanks of volcanoes.

  9. A spatially referenced regression model (SPARROW) for suspended sediment in streams of the conterminous U.S. (United States)

    Schwarz, Gregory E.; Smith, Richard A.; Alexander, Richard B.; Gray, John R.


    Suspended sediment has long been recognized as an important contaminant affecting water resources. Besides its direct role in determining water clarity, bridge scour and reservoir storage, sediment serves as a vehicle for the transport of many binding contaminants, including nutrients, trace metals, semi-volatile organic compounds, and numerous pesticides (U.S. Environmental Protection Agency, 2000a). Recent efforts to address water-quality concerns through the Total Maximum Daily Load (TMDL) process have identified sediment as the single most prevalent cause of impairment in the Nation’s streams and rivers (U.S. Environmental Protection Agency, 2000b). Moreover, sediment has been identified as a medium for the transport and sequestration of organic carbon, playing a potentially important role in understanding sources and sinks in the global carbon budget (Stallard, 1998).A comprehensive understanding of sediment fate and transport is considered essential to the design and implementation of effective plans for sediment management (Osterkamp and others, 1998, U.S. General Accounting Office, 1990). An extensive literature addressing the problem of quantifying sediment transport has produced a number of methods for estimating its flux (see Cohn, 1995, and Robertson and Roerish, 1999, for useful surveys). The accuracy of these methods is compromised by uncertainty in the concentration measurements and by the highly episodic nature of sediment movement, particularly when the methods are applied to smaller basins. However, for annual or decadal flux estimates, the methods are generally reliable if calibrated with extended periods of data (Robertson and Roerish, 1999). A substantial literature also supports the Universal Soil Loss Equation (USLE) (Soil Conservation Service, 1983), an engineering method for estimating sheet and rill erosion, although the empirical credentials of the USLE have recently been questioned (Trimble and Crosson, 2000). Conversely, relatively

  10. Sources and fate of organic matter in suspended and bottom sediments of the Mandovi and Zuari estuaries, Western India

    Digital Repository Service at National Institute of Oceanography (India)

    Shynu, R.; Rao, V.P.; Sarma, V.V.S.S.; Kessarkar, P.M.; ManiMurali, R.

    Organic carbon (OC), total nitrogen (TN) and stable carbon and nitrogen isotopic compositions were measured in suspended particulate matter (SPM) and surface sediment along estuaries of Mandovi and Zuari rivers, two small mountainous river systems...

  11. Physically based method for measuring suspended-sediment concentration and grain size using multi-frequency arrays of acoustic-doppler profilers (United States)

    Topping, David J.; Wright, Scott A.; Griffiths, Ronald; Dean, David


    As the result of a 12-year program of sediment-transport research and field testing on the Colorado River (6 stations in UT and AZ), Yampa River (2 stations in CO), Little Snake River (1 station in CO), Green River (1 station in CO and 2 stations in UT), and Rio Grande (2 stations in TX), we have developed a physically based method for measuring suspended-sediment concentration and grain size at 15-minute intervals using multifrequency arrays of acoustic-Doppler profilers. This multi-frequency method is able to achieve much higher accuracies than single-frequency acoustic methods because it allows removal of the influence of changes in grain size on acoustic backscatter. The method proceeds as follows. (1) Acoustic attenuation at each frequency is related to the concentration of silt and clay with a known grain-size distribution in a river cross section using physical samples and theory. (2) The combination of acoustic backscatter and attenuation at each frequency is uniquely related to the concentration of sand (with a known reference grain-size distribution) and the concentration of silt and clay (with a known reference grain-size distribution) in a river cross section using physical samples and theory. (3) Comparison of the suspended-sand concentrations measured at each frequency using this approach then allows theory-based calculation of the median grain size of the suspended sand and final correction of the suspended-sand concentration to compensate for the influence of changing grain size on backscatter. Although this method of measuring suspended-sediment concentration is somewhat less accurate than using conventional samplers in either the EDI or EWI methods, it is much more accurate than estimating suspended-sediment concentrations using calibrated pump measurements or single-frequency acoustics. Though the EDI and EWI methods provide the most accurate measurements of suspended-sediment concentration, these measurements are labor-intensive, expensive, and

  12. Daily Suspended Sediment Discharge Prediction Using Multiple Linear Regression and Artificial Neural Network (United States)

    Uca; Toriman, Ekhwan; Jaafar, Othman; Maru, Rosmini; Arfan, Amal; Saleh Ahmar, Ansari


    Prediction of suspended sediment discharge in a catchments area is very important because it can be used to evaluation the erosion hazard, management of its water resources, water quality, hydrology project management (dams, reservoirs, and irrigation) and to determine the extent of the damage that occurred in the catchments. Multiple Linear Regression analysis and artificial neural network can be used to predict the amount of daily suspended sediment discharge. Regression analysis using the least square method, whereas artificial neural networks using Radial Basis Function (RBF) and feedforward multilayer perceptron with three learning algorithms namely Levenberg-Marquardt (LM), Scaled Conjugate Descent (SCD) and Broyden-Fletcher-Goldfarb-Shanno Quasi-Newton (BFGS). The number neuron of hidden layer is three to sixteen, while in output layer only one neuron because only one output target. The mean absolute error (MAE), root mean square error (RMSE), coefficient of determination (R2 ) and coefficient of efficiency (CE) of the multiple linear regression (MLRg) value Model 2 (6 input variable independent) has the lowest the value of MAE and RMSE (0.0000002 and 13.6039) and highest R2 and CE (0.9971 and 0.9971). When compared between LM, SCG and RBF, the BFGS model structure 3-7-1 is the better and more accurate to prediction suspended sediment discharge in Jenderam catchment. The performance value in testing process, MAE and RMSE (13.5769 and 17.9011) is smallest, meanwhile R2 and CE (0.9999 and 0.9998) is the highest if it compared with the another BFGS Quasi-Newton model (6-3-1, 9-10-1 and 12-12-1). Based on the performance statistics value, MLRg, LM, SCG, BFGS and RBF suitable and accurately for prediction by modeling the non-linear complex behavior of suspended sediment responses to rainfall, water depth and discharge. The comparison between artificial neural network (ANN) and MLRg, the MLRg Model 2 accurately for to prediction suspended sediment discharge (kg

  13. Shelf Clinoforms and Suspended Sediments at the Northern and Western Margin of the South China Sea (United States)

    Stattegger, K.; Unverricht, D.; Szczucinski, W.; Liu, Z.; Heinrich, C.; Nguyen, T. C.; Lahajnar, N.


    Sediment plumes and shelf clinoforms can be traced almost continuously from the Yangtse until the Mekong Delta as a unique morphodynamics feature of the northern and western marginal parts of the South China Sea. Major sediment plumes originate at the mouths of large rivers, namely the Yangtse, Pearl, Red and Mekong Rivers and extend several hundred kilometers in downdrift direction which is governed mainly by the monsoonal system with the prevailing winter-monsoon winds from NE. Outside the zone of influence of these large rivers we find numerous small mountainous rivers between the Yangtse and Pearl Rivers in SE China and between the Red and Mekong Rivers in central Vietnam providing high amounts of detrital sediments as well. Age control provides clear evidence that the shelf clinoforms developed after 8200 calendar years BP together with a re-organization of the coastal zone and the onset of major modern river deltas after the last phase of accelerated sea-level rise in the Early Holocene, 9000 - 8200 calendar years BP. For the last century 210-Pb activity profiles reveal complex sedimentary processes with event deposition and frequent erosion and re-deposition with average accumulation rates up to 1.5 cm/yr. Suspended sediment contents (SSC) were measured on the Vietnam Shelf. Key regions like the Gulf of Tonkin and the Mekong delta show a strong monsoonal signal as well as a strong tidal signal in the inter-monsoonal period by significant areas of SSCs greater than 25 μl/l even in the inter-monsoonal season. Suspended sediments exhibit distinct seasonal variability while the deposits of shelf clinoforms reflect the average long-term accumulation patterns of terrigenous sediments sometimes winnowed by marine sedimentation and/or masked by bioturbation.

  14. Harmonize input selection for sediment transport prediction (United States)

    Afan, Haitham Abdulmohsin; Keshtegar, Behrooz; Mohtar, Wan Hanna Melini Wan; El-Shafie, Ahmed


    In this paper, three modeling approaches using a Neural Network (NN), Response Surface Method (RSM) and response surface method basis Global Harmony Search (GHS) are applied to predict the daily time series suspended sediment load. Generally, the input variables for forecasting the suspended sediment load are manually selected based on the maximum correlations of input variables in the modeling approaches based on NN and RSM. The RSM is improved to select the input variables by using the errors terms of training data based on the GHS, namely as response surface method and global harmony search (RSM-GHS) modeling method. The second-order polynomial function with cross terms is applied to calibrate the time series suspended sediment load with three, four and five input variables in the proposed RSM-GHS. The linear, square and cross corrections of twenty input variables of antecedent values of suspended sediment load and water discharge are investigated to achieve the best predictions of the RSM based on the GHS method. The performances of the NN, RSM and proposed RSM-GHS including both accuracy and simplicity are compared through several comparative predicted and error statistics. The results illustrated that the proposed RSM-GHS is as uncomplicated as the RSM but performed better, where fewer errors and better correlation was observed (R = 0.95, MAE = 18.09 (ton/day), RMSE = 25.16 (ton/day)) compared to the ANN (R = 0.91, MAE = 20.17 (ton/day), RMSE = 33.09 (ton/day)) and RSM (R = 0.91, MAE = 20.06 (ton/day), RMSE = 31.92 (ton/day)) for all types of input variables.

  15. Effect of water-sediment regulation and its impact on coastline and suspended sediment concentration in Yellow River Estuary

    Directory of Open Access Journals (Sweden)

    Hai-bo Yang


    Full Text Available Implementation of the water-sediment regulation (WSR scheme, mainly focused on solving the sedimentation problems of reservoirs and the lower reaches of the Yellow River, has inevitably influenced the sediment distribution and coastal morphology of the Yellow River Estuary. Using coastline delineation and suspended sediment concentration (SSC retrieval methods, this study investigated water and sediment changes, identified detailed inter-annual and intra-annual variations of the coastline and SSC in the normal period (NP: 1986–2001, before and after the flood season and WSR period (WSRP: 2002–2013, before and after WSR. The results indicate that (1 the sedimentation in the low reaches of the Yellow River turned into erosion from 2002 onward; (2 the inter-annual coastline changes could be divided into an accretion stage (1986–1996, a slow erosion stage (1996–2002, and a slow accretion stage (2002–2013; (3 an intra-annual coastline extension occurred in the river mouth in most years of the WSRP; and (4 the mean intra-annual accretion area was 0.789 km2 in the NP and 4.73 km2 in the WSRP, and the mean SSC increased from 238 mg/L to 293 mg/L in the NP and from 192 mg/L to 264 mg/L in the WSRP.

  16. How do changes in suspended sediment concentration alone influence the size of mud flocs under steady turbulent shearing? (United States)

    Tran, Duc; Kuprenas, Rachel; Strom, Kyle


    Modeling the size and settling velocity of sediment under the influence of flocculation is crucial for the accurate prediction of mud movement and deposition in sediment transport modeling of environments such as agricultural streams, large coastal rivers, estuaries, river plumes, and turbidity currents. Yet, collecting accurate and high resolution data on mud flocs is difficult. As a result, models that account for the influence of flocculation on mud settling velocity are based on sparse data that often present non-congruent relationship in floc properties with basic influencers of flocculations such as suspended sediment concentration. This study examines the influence of suspended sediment concentration on floc size populations within a turbulent suspension. Specifically, the work investigates: (1) the relationship between the equilibrium floc size and suspended sediment concentration under conditions of steady concentration and turbulent shearing; and (2) the speed at which mature flocs adapt to an unsteady drop in the concentration when turbulent shear is constant. Two sets of experiments were used to investigate the target processes. All work was conducted in laboratory mixing tanks using a floc camera and a newly developed image acquisition method. The new method allows for direct imaging and sizing of flocs within turbulent suspensions of clay in concentrations ranging from 15 to 400 mg/L, so that no transfer of the sample to another settling column or imaging tank is needed. The primary conclusions from the two sets of experiments are: (1) that the equilibrium floc size in an energetic turbulent suspension is linearly and positively related to concentration over the range of C = 50 to 400 mg/L, yet with a smaller-than-expected slope based on previous data and models from low-energy environments; and (2) that floc sizes decrease quickly (with a time lag on the order of 1-15 min) to time-varying decreases in concentration at turbulent shearing of G = 50s-1

  17. Exposure of clownfish larvae to suspended sediment levels found on the Great Barrier Reef: Impacts on gill structure and microbiome. (United States)

    Hess, Sybille; Wenger, Amelia S; Ainsworth, Tracy D; Rummer, Jodie L


    Worldwide, increasing coastal development has played a major role in shaping coral reef species assemblages, but the mechanisms underpinning distribution patterns remain poorly understood. Recent research demonstrated delayed development in larval fishes exposed to suspended sediment, highlighting the need to further understand the interaction between suspended sediment as a stressor and energetically costly activities such as growth and development that are essential to support biological fitness. We examined the gill morphology and the gill microbiome in clownfish larvae (Amphiprion percula) exposed to suspended sediment concentrations (using Australian bentonite) commonly found on the inshore Great Barrier Reef. The gills of larvae exposed to 45 mg L(-1) of suspended sediment had excessive mucous discharge and growth of protective cell layers, resulting in a 56% thicker gill epithelium compared to fish from the control group. Further, we found a shift from 'healthy' to pathogenic bacterial communities on the gills, which could increase the disease susceptibility of larvae. The impact of suspended sediments on larval gills may represent an underlying mechanism behind the distribution patterns of fish assemblages. Our findings underscore the necessity for future coastal development to consider adverse effects of suspended sediments on fish recruitment, and consequently fish populations and ecosystem health.

  18. Investigating the temporal dynamics of suspended sediment during flood events with 7Be and 210Pbxs measurements in a drained lowland catchment (United States)

    Le Gall, Marion; Evrard, Olivier; Foucher, Anthony; Laceby, J. Patrick; Salvador-Blanes, Sébastien; Manière, Louis; Lefèvre, Irène; Cerdan, Olivier; Ayrault, Sophie


    Soil erosion is recognized as one of the main processes of land degradation in agricultural areas. High suspended sediment loads, often generated from eroding agricultural landscapes, are known to degrade downstream environments. Accordingly, there is a need to understand soil erosion dynamics during flood events. Suspended sediment was therefore sampled in the river network and at tile drain outlets during five flood events in a lowland drained catchment in France. Source and sediment fallout radionuclide concentrations (7Be, 210Pbxs) were measured to quantify both the fraction of recently eroded particles transported during flood events and their residence time. Results indicate that the mean fraction of recently eroded sediment, estimated for the entire Louroux catchment, increased from 45 ± 20% to 80 ± 20% between December 2013 and February 2014, and from 65 ± 20% to 80 ± 20% in January 2016. These results demonstrate an initial flush of sediment previously accumulated in the river channel before the increasing supply of sediment recently eroded from the hillslopes during subsequent events. This research highlights the utility of coupling continuous river monitoring and fallout radionuclide measurements to increase our understanding of sediment dynamics and improve the management of soil and water resources in agricultural catchments.

  19. Suspended sediment assessment by combining sound attenuation and backscatter measurements - analytical method and experimental validation (United States)

    Guerrero, Massimo; Di Federico, Vittorio


    The use of acoustic techniques has become common for estimating suspended sediment in water environments. An emitted beam propagates into water producing backscatter and attenuation, which depend on scattering particles concentration and size distribution. Unfortunately, the actual particles size distribution (PSD) may largely affect the accuracy of concentration quantification through the unknown coefficients of backscattering strength, ks2, and normalized attenuation, ζs. This issue was partially solved by applying the multi-frequency approach. Despite this possibility, a relevant scientific and practical question remains regarding the possibility of using acoustic methods to investigate poorly sorted sediment in the spectrum ranging from clay to fine sand. The aim of this study is to investigate the possibility of combining the measurement of sound attenuation and backscatter to determine ζs for the suspended particles and the corresponding concentration. The proposed method is moderately dependent from actual PSD, thus relaxing the need of frequent calibrations to account for changes in ks2 and ζs coefficients. Laboratory tests were conducted under controlled conditions to validate this measurement technique. With respect to existing approaches, the developed method more accurately estimates the concentration of suspended particles ranging from clay to fine sand and, at the same time, gives an indication on their actual PSD.

  20. A combined use of acoustic and optical devices to investigate suspended sediment in rivers (United States)

    Guerrero, Massimo; Rüther, Nils; Haun, Stefan; Baranya, Sandor


    The use of acoustic and optic devices has become more and more common for estimating suspended sediment loads in rivers. The echo intensity levels (EIL) recorded by means of an Acoustic Doppler Current Profiler (ADCP) have been applied in different methods, which provided relationships between scattering particles features derived from samples (i.e., concentration and grain size) and corresponding backscattering strength and sound attenuation. At the same time, the laser diffraction was applied by an in-stream sampler (LISST-SL) to measure suspended sediment concentration and the corresponding particle size distribution (PSD). These two techniques exhibited different limitations in terms of the measured range of concentration, sensitivity to a certain spectrum of particle sizes, and instruments deploy feasibility especially in large rivers, in a way that the use of sampled PSD by LISST-SL to validate ADCP methods may not be trivial. The aim of this study was to combine the vertical profiling of EIL by an ADCP with results from LISST-SL, eventually demonstrating the possibility of using moving ADCP measurements to detect different suspended matters along a Danube River section characterized by a small tributary junction. At the same time, this work elucidates optical to acoustic method deviations that hinders an actual validation of ADCP methods based on LISST-SL rather than with physical samplings.

  1. Suspended sediment measurements and calculation of the particle load at HPP Fieschertal (United States)

    Felix, D.; Albayrak, I.; Abgottspon, A.; Boes, R. M.


    In the scope of a research project on hydro-abrasive erosion of Pelton turbines, a field study was conducted at the high-head HPP Fieschertal in Valais, Switzerland. The suspended sediment mass concentration (SSC) and particle size distribution (PSD) in the penstock have been continuously measured since 2012 using a combination of six measuring techniques. The SSC was on average 0.52 g/l and rose to 50 g/l in a major flood event in July 2012. The median particle size d 50 was usually 15 pm, rising up to 100 μm when particles previously having settled in the headwater storage tunnel were re-suspended at low water levels. The annual suspended sediment loads (SSL) varied considerably depending on flood events. Moreover, so-called particle loads (PLs) according to the relevant guideline of the International Electrotechnical Commission (IEC 62364) were calculated using four relations between particle size and the relative abrasion potential. For the investigated HPP, the time series of the SSL and the PLs had generally similar shapes over the three years. The largest differences among the PLs were observed during re-suspension events when the particles were considerably coarser than usual. Further investigations on the effects of particle sizes on hydroabrasive erosion of splitters and cut-outs of coated Pelton turbines are recommended.

  2. Anthropogenic disturbance on sediment transport processes in the tidal power plant (United States)

    Ha, Ho Kyung; Kim, Jong-wook; Woo, Seung-Buhm; Kwon, Hyo Keun


    A series of in-situ mooring observations have been conducted to investigate the anthropogenic disturbance of sediment transport processes in the Sihwa tidal power plant (TPP). The mooring data show that the profiels of velocity and suspended sediment concentration (SSC) were significantly disturbed over the various time scales. On the short-term (flood-ebb) time scale, resuspension of bottom sediment is mainly controlled by the strong jet-flow (>2 m/s) and anticlockwise rotating vortex associated with the artificial discharge. During ebb phase, the strong flow resulted in suspension of high-concentration near-bed sediment and seaward transport of the suspended sediment. After turning to flood phase, the vortex produced secondary SSC peaks, transporting the suspended sediment toward the TPP. The most active suspension of bottom sediment predominantly occurred during 1-2 hr immediately after the start of artificial discharge. On the fortnightly (spring-neap) time scale, SSC during spring tide was approximately 2-5 times higher than that during neap tide. During the presentation, it will be discussed how the periodic artificial discharge can disturb the responses of SSC in the TPP.

  3. Floodplains as a source of fine sediment in grazed landscapes: tracing the source of suspended sediment in the headwaters of an intensively managed agricultural landscape (United States)

    Yu, M.; Rhoads, B. L.; Stumpf, A.


    The flux of fine sediment within agricultural watersheds is an important factor determining the environmental quality of streams and rivers. Despite this importance, the contributions of sediment sources to suspended sediment loads within intensively managed agricultural watersheds remain poorly understood. This study assesses the provenance of fine suspended sediment in the headwater portion of a river flowing through an agricultural landscape in Illinois. Sediment source samples were collected from five potential sources: streambanks, forested floodplain, grassland, and grazed floodplains. Event-based and aggregated suspended sediment samples were collected from the stream at the watershed outlet. Quantitative geochemical fingerprinting techniques and a mixing model were employed to estimate the relative contributions of sediment from five potential sources to the suspended sediment loads. Organic matter content, trace elements, and fallout radionuclides were used as potential tracers. Principal Component analysis was employed to complement the results and Monte Carlo random sampling routine was used to test the uncertainty in estimated contributions of sources to in-stream sediment loads. Results indicate that the majority of suspended sediment is derived from streambanks and grazed floodplains. Erosion of the floodplain both by surface runoff and by streambank erosion from lateral channel migration contributes to the production of fine sediment within the stream system. These results suggest that human activities, in this case grazing, have converted portions of floodplains, normally net depositional environments, into sources of fine sediments. Efforts to reduce fluxes of fine sediment in this intensively managed landscape should focus on degraded floodplain surfaces and eroding channel banks within heavily grazed reaches of the stream.

  4. Near-Bed Monitoring of Suspended Sediment during a Major Flood Event Highlights Deficiencies in Existing Event-Loading Estimates

    Directory of Open Access Journals (Sweden)

    Alistair Grinham


    Full Text Available Rates of fluvial sediment discharge are notoriously difficult to quantify, particularly during major flood events. Measurements are typically undertaken using event stations requiring large capital investment, and the high cost tends to reduce the spatial coverage of monitoring sites. This study aimed to characterise the near-bed suspended sediment dynamics during a major flood event using a low-cost approach. Monitoring nodes consisted of a total suspended sediment (TSS logger, a single stage sampler, and a time-lapse camera for a total cost of less than US$420. Seven nodes were deployed across an elevation gradient on the stream bank of Laidley Creek, Queensland, Australia, and two of these nodes successfully characterised the near-bed suspended sediment dynamics across a major flood event. Near-bed TSS concentrations were closely related to stream flow, with the contribution of suspended bed material dominating the total suspended load during peak flows. Observed TSS concentrations were orders of magnitude higher than historical monitoring data for this site collected using the State government event station. This difference was attributed to the event station pump inlet screening the suspended bed material prior to sample collection. The ‘first flush’ phenomenon was detected and attributed to a local resuspension of muddy crusts immediately upstream of the study site. This low-cost approach will provide an important addition to the existing monitoring of fluvial sediment discharge during flood events.

  5. Sediment and radionuclide transport in rivers: radionuclide transport modeling for Cattaraugus and Buttermilk Creeks, New York

    International Nuclear Information System (INIS)

    Onishi, Y.; Yabusaki, S.B.; Kincaid, C.T.; Skaggs, R.L.; Walters, W.H.


    SERATRA, a transient, two-dimensional (laterally-averaged) computer model of sediment-contaminant transport in rivers, satisfactorily resolved the distribution of sediment and radionuclide concentrations in the Cattaraugus Creek stream system in New York. By modeling the physical processes of advection, diffusion, erosion, deposition, and bed armoring, SERATRA routed three sediment size fractions, including cohesive soils, to simulate three dynamic flow events. In conjunction with the sediment transport, SERATRA computed radionuclide levels in dissolved, suspended sediment, and bed sediment forms for four radionuclides ( 137 Cs, 90 Sr, 239 240 Pu, and 3 H). By accounting for time-dependent sediment-radionuclide interaction in the water column and bed, SERATA is a physically explicit model of radionuclide fate and migration. Sediment and radionuclide concentrations calculated by SERATA in the Cattaraugus Creek stream system are in reasonable agreement with measured values. SERATRA is in the field performance phase of an extensive testing program designed to establish the utility of the model as a site assessment tool. The model handles not only radionuclides but other contaminants such as pesticides, heavy metals and other toxic chemicals. Now that the model has been applied to four field sites, including the latest study of the Cattaraugus Creek stream system, it is recommended that a final model be validated through comparison of predicted results with field data from a carefully controlled tracer test at a field site. It is also recommended that a detailed laboratory flume be tested to study cohesive sediment transport, deposition, and erosion characteristics. The lack of current understanding of these characteristics is one of the weakest areas hindering the accurate assessment of the migration of radionuclides sorbed by fine sediments of silt and clay

  6. Daily suspended sediment concentration simulation using ANN and neuro-fuzzy models. (United States)

    Rajaee, Taher; Mirbagheri, Seyed Ahmad; Zounemat-Kermani, Mohammad; Nourani, Vahid


    In the present study, artificial neural networks (ANNs), neuro-fuzzy (NF), multi linear regression (MLR) and conventional sediment rating curve (SRC) models are considered for time series modeling of suspended sediment concentration (SSC) in rivers. As for the artificial intelligence systems, feed forward back propagation (FFBP) method and Sugeno inference system are used for ANNs and NF models, respectively. The models are trained using daily river discharge and SSC data belonging to Little Black River and Salt River gauging stations in the USA. Obtained results demonstrate that ANN and NF models are in good agreement with the observed SSC values; while they depict better results than MLR and SRC methods. For example, in Little Black River station, the determination coefficient is 0.697 for NF model, while it is 0.457, 0.257 and 0.225 for ANN, MLR and SRC models, respectively. The values of cumulative suspended sediment load estimated by ANN and NF models are closer to the observed data than the other models. In general, the results illustrate that NF model presents better performance in SSC prediction in compression to other models.

  7. Sediment Supply Versus Local Hydraulic Controls on Sediment Transport and Storage in the Rio Grande in the Big Bend Region (United States)

    Dean, D. J.; Topping, D. J.; Schmidt, J. C.


    The Rio Grande in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, has a large sediment supply, and a variable hydrology resulting in rapid channel narrowing during years of low mean and peak flow, and channel widening during rare, large-magnitude floods. This dynamic nature makes the Rio Grande a useful natural laboratory to investigate the relative importance of flow strength and sediment supply in controlling channel change. We analyzed a suite of sediment-transport and geomorphic data to determine the cumulative influence of different flood types on changing channel form. In this study, physically-based analyses suggest that channel change on the Rio Grande is controlled by both changes in flow strength and sediment supply over different spatial and temporal scales. Channel narrowing is primarily caused by sediment supplied to the Rio Grande during flash floods on desert tributaries. Tributary floods have large suspended-sediment concentrations, occur for short durations, and attenuate rapidly downstream in the Rio Grande, depositing much of their sediment in downstream reaches. Long-duration floods on the mainstem are the only floods that have the capacity to enlarge the Rio Grande. These floods, released from upstream dams, can either erode or deposit sediment in the Rio Grande depending upon the antecedent in-channel sediment supply and the magnitude and duration of the flood. Geomorphic and sediment-transport analyses show that sand erosion and deposition during long-duration floods are most strongly controlled by the spatial distribution of flow strength as governed by channel slope. However, temporal changes in the grain size and amount of available sand within the channel, as inferred from comprehensive analyses of suspended-sediment concentration and grain size, control the degree of sediment evacuation or accumulation over large spatial scales.

  8. Geology and geomorphology control suspended sediment yield and modulate increases following timber harvest in temperate headwater streams (United States)

    Bywater-Reyes, Sharon; Segura, Catalina; Bladon, Kevin D.


    Suspended sediment transport is an important contributor to ecologic and geomorphic functions of streams. However, it is challenging to generalize predictions of sediment yield because it is influenced by many factors. In this study, we quantified the relevance of natural controls (e.g., geology, catchment physiography) on suspended sediment yield (SSY) in headwater streams managed for timber harvest. We collected and analyzed six years of data from 10 sites (five headwater sub-catchments and five watershed outlets) in the Trask River Watershed (western Oregon, United States). We used generalized least squares regression models to investigate how the parameters of the SSY rating curve varied as a function of catchment setting, and whether the setting modulated the SSY response to forest harvesting. Results indicated that the highest intercepts (α) of the power relation between unit discharge and SSY were associated with sites underlain primarily by friable rocks (e.g., sedimentary formations). The greatest increases in SSY after forest harvesting (up to an order of magnitude) also occurred at sites underlain by the more friable lithologies. In contrast, basins underlain by resistant lithologies (intrusive rocks) had lower SSY and were more resilient to management-related increases in SSY. As such, the impact of forest management activities (e.g., use of forested buffers; building of new roads) on the variability in SSY was primarily contingent on catchment lithology. Sites with higher SSY, or harvest-related increases in SSY, also generally had a) lower mean elevation and slope, b) greater landscape roughness, and c) lower sediment connectivity. We used principal component analysis (PCA) to further explore the relationship between SSY and several basin physiographic variables. The PCA clearly separated sites underlain by friable geologic units from those underlain by resistant lithologies. Results are consistent with greater rates of weathering and supply of

  9. The influence of grain size, grain color, and suspended-sediment concentration on light attenuation: why fine-grained terrestrial sediment is bad for coral reef ecosystems (United States)

    Storlazzi, Curt; Norris, Benjamin; Rosenberger, Kurt


    Sediment has been shown to be a major stressor to coral reefs globally. Although many researchers have tested the impact of sedimentation on coral reef ecosystems in both the laboratory and the field and some have measured the impact of suspended sediment on the photosynthetic response of corals, there has yet to be a detailed investigation on how properties of the sediment itself can affect light availability for photosynthesis. We show that finer-grained and darker-colored sediment at higher suspended-sediment concentrations attenuates photosynthetically active radiation (PAR) significantly more than coarser, lighter-colored sediment at lower concentrations and provide PAR attenuation coefficients for various grain sizes, colors, and suspended-sediment concentrations that are needed for biophysical modeling. Because finer-grained sediment particles settle more slowly and are more susceptible to resuspension, they remain in the water column longer, thus causing greater net impact by reducing light essential for photosynthesis over a greater duration. This indicates that coral reef monitoring studies investigating sediment impacts should concentrate on measuring fine-grained lateritic and volcanic soils, as opposed to coarser-grained siliceous and carbonate sediment. Similarly, coastal restoration efforts and engineering solutions addressing long-term coral reef ecosystem health should focus on preferentially retaining those fine-grained soils rather than coarse silt and sand particles.

  10. Managing erosion, sediment transport and water quality in drained peatland catchments


    Marttila, H. (Hannu)


    Abstract Peatland drainage changes catchment conditions and increases the transport of suspended solids (SS) and nutrients. New knowledge and management methods are needed to reduce SS loading from these areas. This thesis examines sediment delivery and erosion processes in a number of peatland drainage areas and catchments in order to determine the effects of drainage on sediment and erosion dynamics and mechanics. Results from studies performed in peat mining, peatland forestry and distu...

  11. Geospatial approach towards enumerative analysis of suspended sediment concentration for Ganges-Brahmaputra Bay

    Digital Repository Service at National Institute of Oceanography (India)

    Pandey, P.; Kunte, P.D.

    for the study region, due to data gaps in Landsat ETM+ and secondly due to limited availability of good quality data. 5. The present study assisted in knowing the quantum and dispersal patterns of the suspended sediments in the Bay of Bengal region, which..., University of Petroleum and Energy Studies, Dehradun, for the permission to pursue this summer internship program and their unforgettable help and assistance. Landsat 8 OLI-TIRS 13    data, Landsat 7 ETM, and ETM+ data are downloaded from http...

  12. That sinking feeling: Suspended sediments can prevent the ascent of coral egg bundles (United States)

    Ricardo, Gerard F.; Jones, Ross J.; Negri, Andrew P.; Stocker, Roman


    Spawning synchrony represents a common reproductive strategy in sessile marine organisms and for broadcast spawning corals, buoyancy of egg-sperm bundles is critical to maximise fertilisation at the ocean surface. Here we demonstrate a novel threat to coral reproduction whereby buoyant egg-sperm bundles intercept and are “ballasted” by sediment grains on their journey to the ocean surface, preventing them from reaching the ocean surface and greatly reducing egg-sperm encounter rates. Empirical observations of this mechanism are successfully captured by a mathematical model that predicts the reduction in ascent probability and egg-sperm encounters as a function of sediment load. When applied to 15 m deep reefs, the model predicts that 10% and 50% reductions in egg-sperm encounters occur at 35 mg L-1 and 87 mg L-1 suspended sediment concentrations, respectively, and for a 5 m deep reef a 10% reduction occurs at 106 mg L-1. These concentrations are commonly associated with sediment plumes from dredging or natural resuspension events. The potential for sediments to sink coral gametes highlights the need to carefully manage the timing of turbidity-generating human activities near reefs during spawning periods.

  13. Budgeting suspended sediment fluxes in tropical monsoonal watersheds with limited data: the Lake Tana basin

    Directory of Open Access Journals (Sweden)

    Zimale Fasikaw A.


    Full Text Available Soil erosion decreases soil fertility of the uplands and causes siltation of lakes and reservoirs; the lakes and reservoirs in tropical monsoonal African highlands are especially affected by sedimentation. Efforts in reducing loads by designing management practices are hampered by lack of quantitative data on the relationship of erosion in the watersheds and sediment accumulation on flood plains, lakes and reservoirs. The objective of this study is to develop a prototype quantitative method for estimating sediment budget for tropical monsoon lakes with limited observational data. Four watersheds in the Lake Tana basin were selected for this study. The Parameter Efficient Distributed (PED model that has shown to perform well in the Ethiopian highlands is used to overcome the data limitations and recreate the missing sediment fluxes. PED model parameters are calibrated using daily discharge data and the occasionally collected sediment concentration when establishing the sediment rating curves for the major rivers. The calibrated model parameters are then used to predict the sediment budget for the 1994-2009 period. Sediment retained in the lake is determined from two bathymetric surveys taken 20 years apart whereas the sediment leaving the lake is calculated based on measured discharge and observed sediment concentrations. Results show that annually on average 34 t/ha/year of sediment is removed from the gauged part of the Lake Tana watersheds. Depending on the up-scaling method from the gauged to the ungauged part, 21 to 32 t/ha/year (equivalent to 24-38 Mt/year is transported from the upland watersheds of which 46% to 65% is retained in the flood plains and 93% to 96% is trapped on the flood plains and in the lake. Thus, only 4-7% of all sediment produced in the watersheds leaves the Lake Tana Basin.

  14. Quantification and Analysis of Suspended Sediments Concentration Using Mobile and Static Acoustic Doppler Current Profiler Instruments

    Directory of Open Access Journals (Sweden)

    Angga Dwinovantyo


    Full Text Available The application of Acoustic Doppler Current Profiler (ADCP can be used not only for measuring ocean currents, but also for quantifying suspended sediment concentrations (SSC from acoustic backscatter strength based on sonar principle. Suspended sediment has long been recognized as the largest sources of sea contaminant and must be considered as one of the important parameters in water quality of seawater. This research was to determine SSC from measured acoustic backscattered intensity of static and mobile ADCP. In this study, vertically mounted 400 kHz and 750 kHz static ADCP were deployed in Lembeh Strait, North Sulawesi. A mobile ADCP 307.2 kHz was also mounted on the boat and moved to the predefined cross-section, accordingly. The linear regression analysis of echo intensity measured by ADCP and by direct measurement methods showed that ADCP is a reliable method to measure SSC with correlation coefficient (r 0.92. Higher SSC was observed in low water compared to that in high water and near port area compared to those in observed areas. All of this analysis showed that the combination of static and mobile ADCP methods produces reasonably good spatial and temporal data of SSC.

  15. Laboratory Evaluation of Acoustic Backscatter and LISST Methods for Measurements of Suspended Sediments

    Directory of Open Access Journals (Sweden)

    Ramazan Meral


    Full Text Available The limitation of traditional sampling method to provide detailed spatial andtemporal profiles of suspended sediment concentration has led to an interest in alternativedevices and methods based on scattering of underwater sound and light . In the presentwork, acoustic backscatter and LISST (the Laser In Situ Scattering Transmissometrydevices, and methodologies were given. Besides a laboratory study was conducted tocompare pumping methods for different sediment radiuses at the same concentration. Theglass spheres (ballotini of three different radiuses of 115, 137 and 163 μm were used toobtain suspension in the sediment tower at laboratory. A quite good agreement wasobtained between these methods and pumping results with the range at 60.6-94.2% forsediment concentration and 91.3-100% for radius measurements. These results and theother studies show that these methods have potential for research tools for sedimentstudies. In addition further studies are needed to determine the ability of these methods forsediment measurement under different water and sediment material conditions.

  16. Spatiotemporal dynamics of suspended sediment within an actively urbanizing peri-urban catchment in Portugal (United States)

    Walsh, Rory; Ferreira, Carla; Ferreira, Antonio


    Suspended sediment levels tend to be enhanced in urban catchments, but vary considerably with (amongst many other factors) the degree of active urban development or redevelopment within the catchment and 'urbanization style'. Relatively little, however, is known about the relationship between suspended solids and urbanization style in peri-urban Mediterranean environments. This paper focuses on spatiotemporal suspended sediment dynamics within a typical Portuguese peri-urban catchment, Ribeira dos Covoes, that is undergoing rapid urbanization. The catchment currently has a 40% urban cover, with 17% impervious surfaces, dispersed between woodland (56%) and agricultural areas (4%). The study uses suspended sediment concentration measurements made at the catchment outlet (ESAC) and in three upstream tributaries: (i) Espírito Santo, with a largest urban area (49%); (ii) Porto Bordalo, 39% urbanized; and (iii) Quinta, 22% urbanized, most of which (18%) being an enterprise park under construction. Water sampling was carried out manually during 10 storm hydrographs between October 2011 and March 2013. Suspended sediment concentrations (SSC) were derived by laboratory analysis of the filtered samples using the gravimetric method. In addition total dissolved solids concentrations (TDS) were estimated using conductivity readings. Greatest SSCs were recorded in the Quinta sub-catchment and at the catchment outlet at ESAC (113-4320 mg L-1 and 200-1656 mg L-1, respectively) than in the Espírito Santo and Porto Bordalo sub-catchments (183-852 mg L-1 and 47-598 mg L-1 respectively, despite their greater impervious cover. The greatest SSCs for Quinta result from it containing the construction site, but it showed lower TDS (56-4010 mg L-1), perhaps due to the coarse sandy nature of the construction site. Higher TDS concentrations, however, were displayed in Porto Bordalo (27-5400 mg L-1), possibly due to the loamy soil. Espírito Santo, comprising sandy-loam soils, displayed 27

  17. Use of sediment rating curves and optical backscatter data to characterize sediment transport in the Upper Yuba River watershed, California, 2001-03 (United States)

    Curtis, Jennifer A.; Flint, Lorraine E.; Alpers, Charles N.; Wright, Scott A.; Snyder, Noah P.


    Sediment transport in the upper Yuba River watershed, California, was evaluated from October 2001 through September 2003. This report presents results of a three-year study by the U.S. Geological Survey, in cooperation with the California Ecosystem Restoration Program of the California Bay-Delta Authority and the California Resources Agency. Streamflow and suspended-sediment concentration (SSC) samples were collected at four gaging stations; however, this report focuses on sediment transport at the Middle Yuba River (11410000) and the South Yuba River (11417500) gaging stations. Seasonal suspended-sediment rating curves were developed using a group-average method and non-linear least-squares regression. Bed-load transport relations were used to develop bed-load rating curves, and bed-load measurements were collected to assess the accuracy of these curves. Annual suspended-sediment loads estimated using seasonal SSC rating curves were compared with previously published annual loads estimated using the Graphical Constituent Loading Analysis System (GCLAS). The percent difference ranged from -85 percent to +54 percent and averaged -7.5 percent. During water year 2003 optical backscatter sensors (OBS) were installed to assess event-based suspended-sediment transport. Event-based suspended-sediment loads calculated using seasonal SSC rating curves were compared with loads calculated using calibrated OBS output. The percent difference ranged from +50 percent to -369 percent and averaged -79 percent. The estimated average annual sediment yield at the Middle Yuba River (11410000) gage (5 tons/mi2) was significantly lower than that estimated at the South Yuba River (11417500) gage (14 tons/mi2). In both rivers, bed load represented 1 percent or less of the total annual load throughout the project period. Suspended sediment at the Middle Yuba River (11410000) and South Yuba River (11417500) gages was typically greater than 85 percent silt and clay during water year 2003, and

  18. Effect of Vegetation on Sediment Transport across Salt Marshes (United States)

    Coleman, D. J.; Kirwan, M. L.; Guntenspergen, G. R.; Ganju, N. K.


    Salt marshes are a classic example of ecogeomorphology where interactions between plants and sediment transport govern the stability of a rapidly evolving ecosystem. In particular, plants slow water velocities which facilitates deposition of mineral sediment, and the resulting change in soil elevation influences the growth and species distribution of plants. The ability of a salt marsh to withstand sea level rise (SLR) is therefore dependent, among other factors, on the availability of mineral sediment. Here we measure suspended sediment concentrations (SSC) along a transect from tidal channel to marsh interior, exploring the role biomass plays in regulating the magnitude and spatial variability in vertical accretion. Our study was conducted in Spartina alterniflora dominated salt marshes along the Atlantic Coast from Massachusetts to Georgia. At each site, we deployed and calibrated optical back scatter turbidity probes to measure SSC in 15 minute intervals in a tidal channel, on the marsh edge, and in the marsh interior. We visited each site monthly to measure plant biomass via clip plots and vertical accretion via two types of sediment tiles. Preliminary results confirm classic observations that biomass is highest at the marsh edge, and that SSC and vertical accretion decrease across the marsh platform with distance from the channel. We expect that when biomass is higher, such as in southern sites like Georgia and months late in the growing season, SSC will decay more rapidly with distance into the marsh. Higher biomass will likely also correspond to increased vertical accretion, with the greatest effect at marsh edge locations. Our study will likely demonstrate how salt marsh plants interact with sediment transport dynamics to control marsh morphology and thus contribute to marsh resilience to SLR.

  19. Comparison of phosphorus fraction distribution and influencing factors of suspended and surface sediments in the Tiaoxi watershed, China. (United States)

    Ye, Hongmeng; Yuan, Xuyin; Han, Lei; Yin, Heng; Jin, Jing


    Suspended and surface sediments from the Tiaoxi watershed, fed by the Xitiaoxi and Dongtiaoxi rivers, were analyzed for total phosphorus (TP) and the inorganic P fractions of loosely adsorbed P that were extractable with NH 4 Cl (NH 4 Cl-P), reductant P (BD-P), metal oxide-bound P extractable with NaOH (NaOH-P), and calcium-bound, HCl-extractable P (HCl-P), while other physicochemical compositions were also determined. The spatial variations of P fractions in these sediments were investigated, and the major factors influencing the various fractions were explored by multivariate statistics. Compared to surface sediments, suspended sediments contained considerably higher concentrations of total nitrogen, TP, organic matter, Al, Fe, Mn and biologically available P (BAP, given as NH 4 Cl-P, BD-P and NaOH-P combined) and lower concentrations of Si, Ca and HCl-P in the studied catchments. Dongtiaoxi sediments had higher TP, inorganic phosphorus and HCl-P concentrations and a lower BAP content compared with Xitiaoxi sediments, trends that were associated with local geological backgrounds, landscapes and anthropogenic characteristics. The results of principal component analysis showed different effects of sediment properties on P fraction distributions for Xitiaoxi and Dongtiaoxi sediments. The sediment components and structure exert a strong influence on BAP in Xitiaoxi sediments, in contrast to Dongtiaoxi sediments, where P fractions are mainly affected by urbanization and other anthropogenic activities such as shipping.

  20. Relationship between particle size and radiocesium in fluvial suspended sediment related to the Fukushima Daiichi Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    Kazuya Tanaka


    We collected fluvial suspended sediments in Fukushima after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident and analyzed the 137 Cs concentration in bulk and size-fractioned samples to investigate the particle-size-dependent distribution of radiocesium. The 137 Cs concentration in bulk suspended sediments decreased from August to December 2011, possibly reflecting a decrease of radiocesium concentration in its source materials. Smaller particles had higher radiocesium concentrations, reflecting larger specific surface areas. Silt- and sand-size fractions occupied more than 95 % of the total 137 Cs in the suspended sediments. The contribution of clay-size fractions, which had the highest 137 Cs concentration, was quite small because of their low frequency. A line of the data showed that the particle size distribution of radiocesium was essential to evaluate the migration and distribution of radiocesium in river systems where radiocesium is mainly present as particulate form after the FDNPP accident. (author)

  1. Sediment transport in a large impounded river: The lower Ebro, NE Iberian Peninsula (United States)

    Vericat, Damia; Batalla, Ramon J.


    The sediment transport of the highly regulated lower Ebro River is estimated on the basis of a measuring programme carried out between 2002 and 2004. Total sediment transport, including both suspended load and bedload, was measured upstream and downstream from the Mequinenza and Riba-roja reservoirs, with special attention to the transport during floods. Annual total load upstream from the dams is estimated at around 1.64·10 6 t, of which at least 99% is transported in suspension. Annual total load downstream from the dams is estimated at around 0.45·10 6 t, of which 60% is transported in suspension and the remaining 40% as bedload (mean D50-bl in the range of 32 mm). Total load represents 3% of what was transported at the beginning of the 20th century in the delta plain. Sediment yield is three to four times lower below the dams, a fact that is caused by the trapping of sediment within the reservoirs (around 90% in the case of suspended sediment and 100% in the case of bedload). As a consequence, sediment that is transported downstream from the dams is all entrained from the riverbed and eroded from the banks. The sediment deficit causes a mean riverbed incision of 30 mm per year, as estimated from bedload measurements and by means of scour chains and painted pebbles located between the lowermost dam and the measuring section 28 km downstream. Since floods have been reduced on average by 25% but sediment supply from upstream has been reduced to almost nothing, the river channel of the lower Ebro River will continue exporting sediment both during floods (> 2000 m 3/s, mostly bedload) and frequent high flows (1000 m 3/s to 2000 m 3/s), making the incision progressive unless restoration steps are taken.

  2. Simulation of streamflow and suspended-sediment concentrations and loads in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary, South Texas, 1958-2008 (United States)

    Ockerman, Darwin J.; Heitmuller, Franklin T.


    The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers-Fort Worth District, City of Corpus Christi, Guadalupe-Blanco River Authority, San Antonio River Authority, and San Antonio Water System, developed, calibrated, and tested a Hydrological Simulation Program ? FORTRAN (HSPF) watershed model to simulate streamflow and suspended-sediment concentrations and loads during 1958-2008 in the lower Nueces River watershed, downstream from Lake Corpus Christi to the Nueces Estuary in South Texas. Data available to simulate suspended-sediment concentrations and loads consisted of historical sediment data collected during 1942-82 in the study area and suspended-sediment concentration data collected periodically by the USGS during 2006-07 at three USGS streamflow-gaging stations, Nueces River near Mathis, Nueces River at Bluntzer, and Nueces River at Calallen. The Nueces River near Mathis station is downstream from Wesley E. Seale Dam, completed in 1958 to impound Lake Corpus Christi. Suspended-sediment data collected before and after completion of Wesley E. Seale Dam provide insights to the effects of the dam and reservoir on suspended-sediment loads transported by the lower Nueces River from downstream of the dam to the Nueces Estuary. Annual suspended-sediment loads at a site near the Nueces River at Mathis station were considerably lower, for a given annual mean discharge, after the dam was completed than before the dam was completed. Most of the suspended sediment transported by the Nueces River downstream from Wesley E. Seale Dam occurred during high-flow releases from the dam or during floods. During October 1964-September 1971, about 532,000 tons of suspended sediment were transported by the Nueces River near Mathis. Of this amount, about 473,000 tons, or about 89 percent, were transported by large runoff events (mean streamflow exceeding 1,000 cubic feet per second). To develop the watershed model to simulate suspended-sediment

  3. Sediment transport analysis at event scale in a semi-arid basin of Southern-Italy (United States)

    Bisantino, T.; Gentile, F.; Milillo, F.; Romano, G.; Trisorio Liuzzi, G.


    Erosion at basin scale is a main issue in nowadays research since it plays a role of first level in sustainable management of natural resources (land and water). In particular, in arid and semi-arid regions natural vegetative cover is sparse and runoff events cause high rates of sediment transport, while long periods of drought can be observed. Several types of erosion phenomena affect the torrents in the north-western area of the Puglia Region (Southern-Italy) where flood events are characterised by a considerable amount of suspended solids. In this area the solid load was monitored until 1989 by the National Hydrographic Service using manual sampling. To accurately estimate the sediment transport during flood events and in order to improve the methodologies to assess and predict soil erosion, a watershed representative of the area (Carapelle torrent) was selected, where an experimental station was set up for the continuous measuring of suspended solids. The station is equipped with a dual function infrared sensor (turbidity/suspended solids), a remote data acquisition system, an electromechanical and an ultrasound stage meter. A laboratory test of the turbidity sensor was preliminary performed to evaluate the dual functionality of the instrument (turbidity and suspended sediment concentration) in relation to the variations of sediment concentration and grain size distribution. Successively a field calibration was carried out to determine the relationship between optical and gravimetric data and to check the housing device. Afterwards, the high temporal resolution data collected over a 3-years period (2007-2009) were used to analyze the sediment transport dynamics. The aim of the study is to investigate the relationships in unsteady flows between the sediment concentration and the discharge, and to analyze the relationships at event scale between the sediment budget and some hydrological variables, in order to select the model that best represents the local

  4. Reconstructing the suspended sediment load of the Yellow River since 1470 CE using the Drought and Flood Index (United States)

    Xu, Jiongxin


    The Yellow River of China is well known around the world for its large sediment yield and suspended sediment load (SSL). To better understand the cause of SSL variability, we need long-term perspectives that go back 100-1000 yr. However, few long-term reconstructions have been published, especially with high temporal resolution. In this study, we show that the Drought and Flood Index (IDF) based on historical document analysis can be used as a proxy to reconstruct the SSL, the high-flow season (June-October) stream flow, and the annual precipitation of the middle Yellow River from 1470-1919. The calibration equation explains 57.6% of the variance in the SSL produced from the drainage area between the Hekouzhen and Longmen stations on the Yellow River. Variation in the IDF reflects the variation in the summer monsoon in China that causes the variation in water vapor transport, precipitation, and soil erosion. These links explain the mechanism of reconstructing the SSL based on the IDF. The reconstructed 450 yr series shows that the SSL responds sensitively to El Niño events. The reconstructed SSL may be used as a baseline to assess the effects of human activity on the SSL for the period after 1970, and the reduction in SSL for the period 1971-2013 was estimated as 4.09 × 108 t/yr, accounting for 48.9% of the annual SSL induced by only climate.

  5. Remote Sensing Analysis of Temperature and Suspended Sediment Concentration in Ayeyarwady River in Myanmar (United States)

    Thanda Ko, Nyein; Rutten, Martine


    Detailed spatial coverage of water quality parameters are crucial to better manage rivers. However, collection of water quality parameters is both time consuming and costly for large rivers. This study demonstrates that Operational Land Image (OLI) Sensor on board of Landsat 8 can be successfully applied for the detection of spatial patterns of water temperature as well as suspended sediment concentration (SSC) using the Ayeyarwady river, Myanmar as a case study. Water temperature estimation was obtained from the brightness thermal Band 10 by using the Split-Window algorithm. The study finds that there is a close agreement between the remote sensing temperature and in-situ temperature with relative error in the range from 4.5% to 8.2%. The sediment load of Ayeyarwady river is ranked as the third-largest sediment load among the world's rivers but there is very little known about this important parameter, due to a lack of adequate gauge data. The single band reflectance of Landsat image (Band 5) seems a good indicator for the estimation of SSC with relative error in the range of less than 10% but the developed empirical formula by the power relation with the only seven ground reference points is uncertain to apply for the entire river basin. It is to note that an important constraint for the sediment analysis is the availability of spatial and temporal ground reference data. Future studies should also focus on the improvement of ground reference data points to become more reliable, because most of the river in Asia, especially in Myanmar, don't have readily available continuous ground sediment data points due to lack of measurement gauge stations through the river.

  6. A reassessment of the suspended sediment load in the Madeira River basin from the Andes of Peru and Bolivia to the Amazon River in Brazil, based on 10 years of data from the HYBAM monitoring programme (United States)

    Vauchel, Philippe; Santini, William; Guyot, Jean Loup; Moquet, Jean Sébastien; Martinez, Jean Michel; Espinoza, Jhan Carlo; Baby, Patrice; Fuertes, Oscar; Noriega, Luis; Puita, Oscar; Sondag, Francis; Fraizy, Pascal; Armijos, Elisa; Cochonneau, Gérard; Timouk, Franck; de Oliveira, Eurides; Filizola, Naziano; Molina, Jorge; Ronchail, Josyane


    The Madeira River is the second largest tributary of the Amazon River. It contributes approximately 13% of the Amazon River flow and it may contribute up to 50% of its sediment discharge to the Atlantic Ocean. Until now, the suspended sediment load of the Madeira River was not well known and was estimated in a broad range from 240 to 715 Mt yr-1. Since 2002, the HYBAM international network developed a new monitoring programme specially designed to provide more reliable data than in previous intents. It is based on the continuous monitoring of a set of 11 gauging stations in the Madeira River watershed from the Andes piedmont to the confluence with the Amazon River, and discrete sampling of the suspended sediment concentration every 7 or 10 days. This paper presents the results of the suspended sediment data obtained in the Madeira drainage basin during 2002-2011. The Madeira River suspended sediment load is estimated at 430 Mt yr-1 near its confluence with the Amazon River. The average production of the Madeira River Andean catchment is estimated at 640 Mt yr-1 (±30%), the corresponding sediment yield for the Andes is estimated at 3000 t km-2 yr-1 (±30%), and the average denudation rate is estimated at 1.20 mm yr-1 (±30%). Contrary to previous results that had mentioned high sedimentation rates in the Beni River floodplain, we detected no measurable sedimentation process in this part of the basin. On the Mamoré River basin, we observed heavy sediment deposition of approximately 210 Mt yr-1 that seem to confirm previous studies. But while these studies mentioned heavy sedimentation in the floodplain, we showed that sediment deposition occurred mainly in the Andean piedmont and immediate foreland in rivers (Parapeti, Grande, Pirai, Yapacani, Chimoré, Chaparé, Secure, Maniqui) with discharges that are not sufficiently large to transport their sediment load downstream in the lowlands.

  7. Organic Contaminants Associated With Suspended Sediment Collected During Five Cruises of the Mississippi River and Its Principal Tributaries, May 1988 to June 1990

    National Research Council Canada - National Science Library

    Rostad, Colleen E; Bishop, LaDonna M; Ellis, Geoffrey S; Leiker, Thomas J; Monsterleet, Stephanie G; Pereira, Wilfred E


    ... sediment smaller than 63 micrometers. Sample collection involved pumping discharge- weighted volumes of river water along a cross section of the river into a continuous-flow centrifuge to isolate the suspended sediment...

  8. Vertical suspended sediment fluxes observed from a formation of underwater gliders (United States)

    Merckelbach, Lucas; Riethmueller, Rolf


    In order to understand and predict the pathways and deposition of fine sediments in coastal regions valid parameterisations of the fluxes across interfaces (sea bed - water column or a pycnocline) are paramount. Traditionally, these parameterisations are based on the concept of a critical shear stress, but more recently a probabilistic approach has been proposed, in which the resuspension of sediment is assumed to have a certain likelihood, depending on the external forcing. Both approaches find their justification, to some extent, from the results of laboratory experiments, however, in-situ data, essential for model validation, are scarce. In this study we develop a field method to estimate the (fine) sediment fluxes between the seabed and the water column, and across the pycnocline. The method is applied to a stratified shallow sea (the North Sea in Summer). In order to assess the results, these fluxes are interpreted in terms of bottom shear stress and current shear between upper and lower layer, respectively. The method was tested in an experiment with two underwater gliders in Summer 2013 in the German Bight. Both gliders were equipped with optical backscatter sensors, the measurements of which serve as a proxy for suspended sediment concentration. The profiling character of the gliders allows to calculate the rate of change of the layer-averaged sediment concentration, as observed by the platform. The local, Lagrangian rate of change of sediment concentration is the balance between the fluxes across the layer's interfaces. Due to a horizontal speed of the glider of about 0.5 m/s, horizontal gradients in sediment concentration cause the observed and the local rate of change of sediment concentration to be significantly different. The novelty of this experiment was that the two gliders were flown in a rigid formation, where one glider trailed the other at a more or less constant distance of 5 km, controlled by an algorithm. This allowed the local rate of change

  9. Annual suspended-sediment loads in the Colorado River near Cisco, Utah, 1930-82 (United States)

    Thompson, K.R.


    The Colorado River upstream of gaging station 09180500 near Cisco, Utah, drains about 24,100 square miles in Utah and Colorado. Altitudes in the basin range from 12,480 feet near the headwaters to 4,090 feet at station 09180500. The average annual precipitation for 1894-1982 near the station was 7.94 inches. The average annual precipitation near the headwaters often exceeds 50 inches. Rocks ranging in age from Precambrian to Holocene are exposed in the drainage basin upstream from station 09180500. Shale, limestone, siltstone, mudstone, and sandstone probably are the most easily eroded rocks in the basin, and they contribute large quantities of sediment to the Colorado River. During 1930-82, the U.S. Geological Survey collected records of fluvial sediment at station 09180500. Based on these records, the mean annual suspended-sediment load was 11,390,000 tone, ranging from 2,038,000 tons in water year 1981 to 35,700,000 tons in water year 1938. The minimum daily load of 14 tons was on August 22, 1960, and the maximum daily load of 2,790,000 tons was on October 14, 1941. (USGS)

  10. Implications for post-comminution processes in subglacial suspended sediment using coupled radiogenic strontium and neodymium isotopes (United States)

    Clinger, Anna E.; Aciego, Sarah M.; Stevenson, Emily I.; Arendt, Carli A.; Robbins, Mark J.


    Enhanced physical weathering rates in subglacial systems promote high levels of comminution, transport, and deposition of fine-grained sediment within the subglacial drainage network. The impact of shifts in sediment loads from variations in meltwater flux, and their effects on downstream ecosystems, remains poorly quantified and places a fundamental importance on our ability to characterize subglacial depositional environments. Here, for the first time, we assess the seasonal evolution of the subglacial suspended sediment using coupled radiogenic strontium (87Sr/86Sr) and neodymium (143Nd/144Nd) isotopic ratios with elemental ratios and in situ measurements. Weathering rates in fluvial and riverine systems have been traditionally assessed using radiogenic isotopic tracers: 143Nd/144Nd ratios relate to the crustal age whereas 87Sr/86Sr ratios relate to age and preferential mineral dissolution. Thus relative shifts in these ratios will allow us to characterize distinct sediment transport networks. We apply this technique to the Lemon Creek Glacier (LCG), Alaska, USA, and to the Athabasca Glacier (AG), Alberta, CA. At the LCG, the 143Nd/144Nd values range from εNd of - 4.6 (0.9) to - 8.7 (0.2), which suggests a poorly mixed sediment flux. However, the greatest period of variability may correlate with the drainage of a supraglacial lake and suggests caution should be exerted in time-scale 143Nd/144Nd provenance studies that may be affected by climatic disturbances. In contrast, limited variation is observed within the AG 143Nd/144Nd seasonal record. A consistent, direct relation between the Rb/Sr elemental ratio and the 87Sr/86Sr ratio proves interesting as it enables us to unravel incongruent weathering trends in the radiogenic Sr record. Correlation between the 87Sr/86Sr and total discharge suggests that the process is partially controlled by mantling of the bedrock, which can be detected using post-comminution ages. While the subglacial structure may be enabled by

  11. Sediment transport in steep forested catchments - An assessment of scale and disturbance (United States)

    Hancock, G. R.; Hugo, J.; Webb, A. A.; Turner, L.


    Stream sediment loads (both bedload and suspended sediment) are problematic to measure due to the time and equipment needed. There is a dearth of such data sets globally let alone for Australia. However, such data are needed to quantify sediment transport type and rates, landscape evolution, effect of human disturbance as well as patterns and temporal response. Here we present the findings from 8 steepslope forested catchments dominated by headwater streams (size range 15-100 ha) in south-eastern Australia where both bedload and suspended load have been measured over multiple years. The results demonstrate that suspended load is the dominant component and there is no consistent suspended to bedload ratio for the catchments. The suspended sediment to bedload ratio appears to be catchment specific. There was no relationship between total load (or bedload/suspended load) and average catchment slope, stream length, shape or any geomorphic descriptor. However catchment total load was found to be significantly related to catchment area. Of the 8 catchments examined here, 6 had been harvested for timber in previous decades (with large areas of forest removed) while 2 catchments had minimal disturbance (Control catchments). There was no difference in sediment loads from the harvested and Control catchments. The results demonstrate that although land disturbance had previously occurred the management practices employed in each catchment were effective in the long term. This provides confidence that the forest harvesting and subsequent management do not produce detrimental effects in the medium to long term. An assessment of erosion rates and likely soil production rates suggests that the catchments are eroding soil at the rate it is being produced.

  12. Field Observations of Hydrodynamics, Sediment Transport, and Water and Sediment Quality in the Hudson-Raritan Estuary (United States)

    Bruno, M. S.; Glenn, S.; Chant, R.; Rankin, K.; Korfiatis, G.; Dimou, N.; Creed, E.; Fullerton, B.; Pence, A.; Burke, P.; Haldeman, C.; Hires, R.; Hunter, E.


    The New York-New Jersey Harbor estuary system is of enormous ecological and economic importance to the region. The presence of toxic chemicals in the water and sediments results in reduced water quality, fisheries restrictions/advisories, and general adverse impacts to the estuarine ecosystem. The Port of New York and New Jersey is central to the economy of the region. However, in recent years, problems associated with the management of contaminated dredged material, including high costs and the lack of suitable disposal/use alternatives, have threatened to impact the volume of shipping in the Harbor. Sources of contaminants include atmospheric deposition, municipal and industrial wastewater treatment facilities, combined sewer and stormwater outfalls, and rainfall-induced runoff (non-point sources). In addition, Harbor sediments can act as a continuing source as they are re-suspended and moved throughout the system by both natural and man-made means. As part of the New Jersey Toxics Reduction Workplan, Stevens Institute of Technology and Rutgers University are conducting hydrodynamic, sediment transport, and water and suspended sediment quality measurements in Newark Bay, the Arthur Kill and the Kill van Kull. The goals of the project include: (1) collection of high resolution (event-driven and long-term) hydrodynamic, sediment transport and water and suspended sediment quality measurements for use in the assessment of the dominant physics of the system and in the development of a combined hydrodynamic-sediment transport-water/sediment quality model for the region. (2) identification of those tributaries to NY-NJ Harbor that are significant sources of the chemicals of concern, and evaluation of the importance of non-point sources and existing contaminated bottom sediments as sources of the chemicals of concern. (3) identification of point discharges that represent significant sources of the chemicals of concern. Observations were obtained over a two-year period

  13. A Field Exercise in Fluvial Sediment Transport. (United States)

    Tharp, Thomas M.


    Describes an investigation which introduces the mathematical principles of stream hydraulics and fluvial sediment in a practical context. The investigation has four stages: defining hydrology of the stream; defining channel hydraulics in a study reach; measuring grain size; and calculating transportable grain size and comparing measure stream-bed…

  14. A Sediment Transport Model for Sewers

    DEFF Research Database (Denmark)

    Mark, Ole; Larsson, Johan; Larsen, Torben


    This paper describes a mathematical model for transport processes in sewers. The model consists of three sub models, a surface model for the description of the buildup and the washoff of sediment particles from the surface area, a morphological model and an advection-dispersion model. The model...

  15. Comparison of load estimation techniques and trend analysis for nitrogen, phosphorus, and suspended sediment in the Eucha-Spavinaw Basin, northwestern Arkansas and northeastern Oklahoma, 2002-10 (United States)

    Esralew, Rachel A.; Andrews, William J.; Allen, Monica L.; Becker, Carol J.


    The City of Tulsa, Oklahoma, uses water from Lake Eucha and Spavinaw Lake in the Eucha-Spavinaw basin of northwestern Arkansas and northeastern Oklahoma for public water supply. Increases in algal biomass, which cause taste and odor problems in drinking water produced from the lakes, may be attributable to increases in nitrogen and phosphorus concentrations in the lakes and in streams discharging to the lakes. To evaluate transport of nitrogen, phosphorus, and suspended sediment in this basin, loads and temporal trends were evaluated for five streamflow-gaging stations in the Spavinaw and Beaty Creek basins.

  16. Automatic real-time control of suspended sediment based upon high frequency in situ measurements of nephelometric turbidity (United States)

    Jack Lewis; Rand Eads


    Abstract - For estimating suspended sediment concentration (SSC) in rivers, turbidity is potentially a much better predictor than water discharge. Since about 1990, it has been feasible to automatically collect high frequency turbidity data at remote sites using battery-powered turbidity probes that are properly mounted in the river or stream. With sensors calibrated...

  17. Polybrominated diphenyl ethers in influents, suspended particulate matter, sediments, sewage treatment plant and effluents and biota from the Netherlands

    NARCIS (Netherlands)

    Boer, de J.; Wester, P.G.; Horst, van der A.; Leonards, P.E.G.


    Polybrominated diphenyl ethers (PBDEs) have been determined in 133 samples of suspended particulate matter (SPM), sediments, sewage treatment plant (STP) influents and effluents, fish and mussels from various locations in The Netherlands, as a part of a large Dutch national study on estrogenic

  18. Characteristics of Sediment Transportation in Two Contrasting Oak Forested Watersheds in the Lesser Central Himalaya, India (United States)

    Qazi, N. U. Q.; Bruijnzeel, S., Sr.; Rai, S. P., Sr.


    Sediment transfer from mountainous areas to lowland areas is one of the most important geomorphological processes globally with the bulk of the sediment yield from such areas typically deriving from mass wastage processes. This study presents monthly, seasonal and annual variations in sediment transport (both suspended load and bedload) as well as dissolved loads over three consecutive water years (2008-2011) for two small forested watersheds with contrasting levels of forest disturbance in the Lesser Himalaya of Northwest India. Seasonal and annual suspended sediment yields were strongly influenced by amounts of rainfall and streamflow and showed a 10-63 fold range between wet and dry years. Of the annual load, some 93% was produced on average during the monsoon season (June-September). Sediment production by the disturbed forest catchment was 1.9-fold (suspended sediment) to 5.9-fold (bedload) higher than that for the well-stocked forest catchment. By contrast, dissolved loads varied much less between years, seasons (although minimal during the dry summer season), and degree of forest disturbance. Total mechanical denudation rates were 1.6 times and 4.6 times larger than chemical denudation rates for the little disturbed and the heavily disturbed forest catchment, respectively whereas overall denudation rates were estimated at 0.69 and 1.04 mm per 1000 years, respectively.

  19. Extending the turbidity record: making additional use of continuous data from turbidity, acoustic-Doppler, and laser diffraction instruments and suspended-sediment samples in the Colorado River in Grand Canyon (United States)

    Voichick, Nicholas; Topping, David J.


    range of sediment concentrations in the study area using data from the ADP instruments is particularly useful for biological studies. In Grand Canyon, turbidity has been correlated with food availability for aquatic organisms (gross primary production) as well as with fish behavior specific to predator-prey interactions. On the basis of the complete “extended” turbidity record and the relation between suspended-sediment concentration and turbidity, levels were higher before the construction of Glen Canyon Dam by a factor of approximately 2,000 at the Lees Ferry monitoring station (15 miles downstream from the dam) and by a factor of approximately 20 at the monitoring station 87 miles downstream from Lees Ferry (102 miles downstream from the dam). A comparison of turbidity data with data from Laser In-Situ Scattering and Transmissometry (LISST) laser-diffraction instruments, suspended-sediment concentration data, and ADP data shows the influence of the physical properties of suspended sediment. Apparent outliers in relations between turbidity, ADP, and suspended-sediment data during two events within the study period, a 2007 tributary flood from a watershed altered by a recent wildfire and a 2008 experimental controlled-flood release from Glen Canyon Dam, are explained in part by atypical grain sizes, shapes, densities, colors, and (or) clay mineral assemblages of suspended sediment occurring in the Colorado River during these two events. These analyses demonstrate the value of using multiple data-collection strategies for turbidity and sediment-transport studies and of continuous monitoring for capturing the full range and duration of turbidity and sediment-transport conditions, identifying the provenance of the sediment causing turbidity, and detecting physical and chemical processes that may be important for management of critical physical and biological resources.

  20. Tracing cohesive sediment transportation at river mouths around Tokyo, Japan by Cesium originated from Fukushima Daiichi Power Plant (United States)

    koibuchi, Y.


    Sediment transport at river mouths, which consists of suspended-load and bed-load, has not been fully understood, since bed-load transport of cohesive sand is difficult to observe. Especially, the impact of sediment transport on the total amount of fine-grained cohesive sediment has not been elucidated. Cesium-134 and cesium-137 were spread from the Fukushima Daiichi Nuclear Power Plant (FDNPP) after the earthquake of March 11 of 2011, and attached to the fine-grained sand on the land. The contaminated sand flowed into the river mouths through the rivers possibly due to the complex physical processes in estuarine areas. To evaluate the fine-grained sediment transport around Tokyo and Tokyo Bay, field observations were carried out utilizing radionuclide originated from FDNPP as an effective tracer. The cohesive sediment transport at three different river mouths around Tokyo was successfully quantified. The cohesive sediment transport deposited in the estuary was found to be greatly dependent on the land use, geometry, river discharge and salinity. In addition,the transport driven by the rainfall was minute, and its behavior was quite different from suspended solids. Although further field observations of radionuclide are necessary, it is clear that fine-grained sediment in the bay from rivers already settled on the river mouth by aggregation. The settled sand will not move even in rainfall events. Consequently, the transport of radionuclide to the Pacific Ocean may not occur.; Cesium distribution around Tokyo Bay ; Cesium Concentration in Edogawa river

  1. Application of dimensionless sediment rating curves to predict suspended-sediment concentrations, bedload, and annual sediment loads for rivers in Minnesota (United States)

    Ellison, Christopher A.; Groten, Joel T.; Lorenz, David L.; Koller, Karl S.


    Consistent and reliable sediment data are needed by Federal, State, and local government agencies responsible for monitoring water quality, planning river restoration, quantifying sediment budgets, and evaluating the effectiveness of sediment reduction strategies. Heightened concerns about excessive sediment in rivers and the challenge to reduce costs and eliminate data gaps has guided Federal and State interests in pursuing alternative methods for measuring suspended and bedload sediment. Simple and dependable data collection and estimation techniques are needed to generate hydraulic and water-quality information for areas where data are unavailable or difficult to collect.The U.S. Geological Survey, in cooperation with the Minnesota Pollution Control Agency and the Minnesota Department of Natural Resources, completed a study to evaluate the use of dimensionless sediment rating curves (DSRCs) to accurately predict suspended-sediment concentrations (SSCs), bedload, and annual sediment loads for selected rivers and streams in Minnesota based on data collected during 2007 through 2013. This study included the application of DSRC models developed for a small group of streams located in the San Juan River Basin near Pagosa Springs in southwestern Colorado to rivers in Minnesota. Regionally based DSRC models for Minnesota also were developed and compared to DSRC models from Pagosa Springs, Colorado, to evaluate which model provided more accurate predictions of SSCs and bedload in Minnesota.Multiple measures of goodness-of-fit were developed to assess the effectiveness of DSRC models in predicting SSC and bedload for rivers in Minnesota. More than 600 dimensionless ratio values of SSC, bedload, and streamflow were evaluated and delineated according to Pfankuch stream stability categories of “good/fair” and “poor” to develop four Minnesota-based DSRC models. The basis for Pagosa Springs and Minnesota DSRC model effectiveness was founded on measures of goodness

  2. Suspended sediment, turbidity, and stream water temperature in the Sauk River Basin, western Washington, water years 2012-16 (United States)

    Jaeger, Kristin L.; Curran, Christopher A.; Anderson, Scott W.; Morris, Scott T.; Moran, Patrick W.; Reams, Katherine A.


    The Sauk River is a federally designated Wild and Scenic River that drains a relatively undisturbed landscape along the western slope of the North Cascade Mountain Range, Washington, which includes the glaciated volcano, Glacier Peak. Naturally high sediment loads characteristic of basins draining volcanoes like Glacier Peak make the Sauk River a dominant contributor of sediment to the downstream main stem river, the Skagit River. Additionally, the Sauk River serves as important spawning and rearing habitat for several salmonid species in the greater Skagit River system. Because of the importance of sediment to morphology, flow-conveyance, and ecosystem condition, there is interest in understanding the magnitude and timing of suspended sediment and turbidity from the Sauk River system and its principal tributaries, the White Chuck and Suiattle Rivers, to the Skagit River.Suspended-sediment measurements, turbidity data, and water temperature data were collected at two U.S. Geological Survey streamgages in the upper and middle reaches of the Sauk River over a 4-year period extending from October 2011 to September 2015, and at a downstream location in the lower river for a 5-year period extending from October 2011 to September 2016. Over the collective 5-year study period, mean annual suspended-sediment loads at the three streamgages on the upper, middle, and lower Sauk River streamgages were 94,200 metric tons (t), 203,000 t, and 940,000 t streamgages, respectively. Fine (smaller than 0.0625 millimeter) total suspended-sediment load averaged 49 percent at the upper Sauk River streamgage, 42 percent at the middle Sauk River streamgage, and 34 percent at the lower Sauk River streamgage.

  3. The effect of weathering in the Buyukmelen River basin on the geochemistry of suspended and bed sediments and the hyrogeochemical characteristics of river water, Duzce, Turkey (United States)

    Pehlivan, Rustem


    The Buyukmelen River is expected to be a water source that can supply the drinking water needs of Istanbul until 2040. The drinking and utility water needs of Istanbul are to transport water from the Buyukmelen River to Istanbul via pipeline and pump it into the Alibeykoy and Omerli reservoirs when their water levels drop. The Buyukmelen River is located in the province of Duzce in 170 km east of Istanbul and its water basin is approximately 2250 km 2. The Buyukmelen River flows muddy in the rainy season and into the Black Sea. The chemical compositions of natural waters alter due to interaction with geological formations, physical and chemical weathering of various rocks and the effects of mining and agricultural production. A research was conducted at the Buyukmelen River basin to determine the effects of hydrological processes. Therefore, the samples of rocks, soil, stream water, suspended and bed sediment were collected from the Buyukmelen River basin. Geochemical and water chemistry analyses of samples were performed at ALS Chemex laboratories, Canada. The bed sediments contain quartz, calcite, plagioclase, amphibole and clay minerals. The clay minerals in the suspended and bed sediment samples are kaolinite, smectite and illite. The water samples collected from the Aksu, Kucukmelen, Asarsu and Ugursuyu streams and the Buyukmelen River in winter (December 2005) and summer (June 2006) periods are rich in Ca and HCO 3 ions. The ions most abundant in rainfall sample are HCO 3 and Na. The ion compositions of surface waters have increased due to the weathering of limestone, agglomerate and volcanic sandstones, light acidic rainfall, semi-arid Black Sea climate in the Buyukmelen basin. The suspended sediment amount of the Buyukmelen River in the rainy season (December 2005) is 174 mg/l. According to the water contamination regulation of Turkey, the Buyukmelen Rivers belongs to quality class 4 based on Al ion and to quality class 3 based on Fe ion in winter period

  4. Optical Measurement of Cell Colonization Patterns on Individual Suspended Sediment Aggregates (United States)

    Nguyen, Thu Ha; Tang, Fiona H. M.; Maggi, Federico


    Microbial processes can make substantial differences to the way in which particles settle in aquatic environments. A novel method (OMCEC, optical measurement of cell colonization) is introduced to systematically map the biological spatial distribution over individual suspended sediment aggregates settling through a water column. OMCEC was used to investigate (1) whether a carbon source concentration has an impact on cell colonization, (2) how cells colonize minerals, and (3) if a correlation between colonization patterns and aggregate geometry exists. Incubations of Saccharomyces cerevisiae and stained montmorillonite at four sucrose concentrations were tested in a settling column equipped with a full-color microparticle image velocimetry system. The acquired high-resolution images were processed to map the cell distribution on aggregates based on emission spectra separation. The likelihood of cells colonizing minerals increased with increasing sucrose concentration. Colonization patterns were classified into (i) scattered, (ii) well touched, and (iii) poorly touched, with the second being predominant. Cell clusters in well-touched patterns were found to have lower capacity dimension than those in other patterns, while the capacity dimension of the corresponding aggregates was relatively high. A strong correlation of colonization patterns with aggregate biomass fraction and properties suggests dynamic colonization mechanisms from cell attachment to minerals, to joining of isolated cell clusters, and finally cell growth over the entire aggregate. This paper introduces a widely applicable method for analyses of microbial-affected sediment dynamics and highlights the microbial control on aggregate geometry, which can improve the prediction of large-scale morphodynamics processes.

  5. Fluvial sediment transport in a glacier-fed high-mountain river (Riffler Bach, Austrian Alps) (United States)

    Morche, David; Weber, Martin; Faust, Matthias; Schuchardt, Anne; Baewert, Henning


    High-alpine environments are strongly affected by glacier retreat since the Little Ice Age (LIA). Due to ongoing climate change the hydrology of proglacial rivers is also influenced. It is expected that the growing proportions of snow melt and rainfall events will change runoff characteristics of proglacial rivers. Additionally, the importance of paraglacial sediment sources in recently deglaciating glacier forefields is increasing, while the role of glacial erosion is declining. Thus complex environmental conditions leading to a complex pattern of fluvial sediment transport in partly glaciated catchments of the European Alps. Under the umbrella of the joint PROSA-project the fluvial sediment transport of the river Riffler Bach (Kaunertal, Tyrol, Austria) was studied in 3 consecutive ablation seasons in order to quantify sediment yields. In June 2012 a probe for water level and an automatic water sampler (AWS) were installed at the outlet of the catchment (20km2). In order to calculate annual stage-discharge-relations by the rating-curve approach, discharge (Q) was repeatedly measured with current meters and by salt dilution. Concurrent to the discharge measurements bed load was collected using a portable Helley-Smith sampler. Bed load samples were weighted and sieved in the laboratory to gain annual bed load rating curves and grain size distributions. In total 564 (2012: 154, 2013: 209, 2014: 201) water samples were collected and subsequently filtered to quantify suspended sediment concentrations (SSC). Q-SSC-relations were calculated for single flood events due to the high variability of suspended sediment transport. The results show a high inter- and intra-annual variability of solid fluvial sediment transport, which can be explained by the characteristics of suspended sediment transport. Only 13 of 22 event-based Q-SSC-relations show causal dependency. In 2012, during a period with multiple pluvial-induced peak discharges most sediment was transported. On the

  6. Longshore sediment transport model for the Indian west coast

    Digital Repository Service at National Institute of Oceanography (India)

    Chandramohan, P.; Nayak, B

    Longshore sediment transport rates for the Indian west coast from Cochin to Porbandar are estimated from ship observed wave data (1968 to 1986). The sediment transport rate is relatively high during the southwest monsoon period from June...

  7. Comparison of fluvial suspended-sediment concentrations and particle-size distributions measured with in-stream laser diffraction and in physical samples (United States)

    Czuba, Jonathan A.; Straub, Timothy D.; Curran, Christopher A.; Landers, Mark N.; Domanski, Marian M.


    Laser-diffraction technology, recently adapted for in-stream measurement of fluvial suspended-sediment concentrations (SSCs) and particle-size distributions (PSDs), was tested with a streamlined (SL), isokinetic version of the Laser In-Situ Scattering and Transmissometry (LISST) for measuring volumetric SSCs and PSDs ranging from 1.8-415 µm in 32 log-spaced size classes. Measured SSCs and PSDs from the LISST-SL were compared to a suite of 22 datasets (262 samples in all) of concurrent suspended-sediment and streamflow measurements using a physical sampler and acoustic Doppler current profiler collected during 2010-12 at 16 U.S. Geological Survey streamflow-gaging stations in Illinois and Washington (basin areas: 38 – 69,264 km2). An unrealistically low computed effective density (mass SSC / volumetric SSC) of 1.24 g/ml (95% confidence interval: 1.05-1.45 g/ml) provided the best-fit value (R2 = 0.95; RMSE = 143 mg/L) for converting volumetric SSC to mass SSC for over 2 orders of magnitude of SSC (12-2,170 mg/L; covering a substantial range of SSC that can be measured by the LISST-SL) despite being substantially lower than the sediment particle density of 2.67 g/ml (range: 2.56-2.87 g/ml, 23 samples). The PSDs measured by the LISST-SL were in good agreement with those derived from physical samples over the LISST-SL's measureable size range. Technical and operational limitations of the LISST-SL are provided to facilitate the collection of more accurate data in the future. Additionally, the spatial and temporal variability of SSC and PSD measured by the LISST-SL is briefly described to motivate its potential for advancing our understanding of suspended-sediment transport by rivers.

  8. Intelligent Models Performance Improvement Based on Wavelet Algorithm and Logarithmic Transformations in Suspended Sediment Estimation

    Directory of Open Access Journals (Sweden)

    R. Hajiabadi


    Full Text Available Introduction One reason for the complexity of hydrological phenomena prediction, especially time series is existence of features such as trend, noise and high-frequency oscillations. These complex features, especially noise, can be detected or removed by preprocessing. Appropriate preprocessing causes estimation of these phenomena become easier. Preprocessing in the data driven models such as artificial neural network, gene expression programming, support vector machine, is more effective because the quality of data in these models is important. Present study, by considering diagnosing and data transformation as two different preprocessing, tries to improve the results of intelligent models. In this study two different intelligent models, Artificial Neural Network and Gene Expression Programming, are applied to estimation of daily suspended sediment load. Wavelet transforms and logarithmic transformation is used for diagnosing and data transformation, respectively. Finally, the impacts of preprocessing on the results of intelligent models are evaluated. Materials and Methods In this study, Gene Expression Programming and Artificial Neural Network are used as intelligent models for suspended sediment load estimation, then the impacts of diagnosing and logarithmic transformations approaches as data preprocessor are evaluated and compared to the result improvement. Two different logarithmic transforms are considered in this research, LN and LOG. Wavelet transformation is used to time series denoising. In order to denoising by wavelet transforms, first, time series can be decomposed at one level (Approximation part and detail part and second, high-frequency part (detail will be removed as noise. According to the ability of gene expression programming and artificial neural network to analysis nonlinear systems; daily values of suspended sediment load of the Skunk River in USA, during a 5-year period, are investigated and then estimated.4 years of

  9. Uncertanity Analysis in Parameter Estimation of Coupled Bacteria-Sediment Fate and Transport in Streams (United States)

    Massoudieh, A.; Le, T.; Pachepsky, Y. A.


    E. coli is widely used as an fecal indicator bacteria in streams. It has been shown that the interaction between sediments and the bacteria is an important factor in determining its fate and transport in water bodies. In this presentation parameter estimation and uncertainty analysis of a mechanistic model of bacteria-sediment interaction respectively using a hybrid genetic algorithm and Makov-Chain Monte Carlo (MCMC) approach will be presented. The physically-based model considers the advective-dispersive transport of sediments as well as both free-floating and sediment-associated bacteria in the water column and also the fate and transport of bacteria in the bed sediments in a small stream. The bed sediments are treated as a distributed system which allows modeling the evolution of the vertical distribution of bacteria as a result of sedimentation and resuspension, diffusion and bioturbation in the sediments. One-dimensional St. Venant's equation is used to model flow in the stream. The model is applied to sediment and E. coli concentration data collected during a high flow event in a small stream historically receiving agricultural runoff. Measured total suspended sediments and total E. coli concentrations in the water column at three sections of the stream are used for the parameter estimation. The data on the initial distribution of E. coli in the sediments was available and was used as the initial conditions. The MCMC method is used to estimate the joint probability distribution of model parameters including sediment deposition and erosion rates, critical shear stress for deposition and erosion, attachment and detachment rate constants of E. coli to/from sediments and also the effective diffusion coefficients of E. coli in the bed sediments. The uncertainties associated with the estimated parameters are quantified via the MCMC approach and the correlation between the posterior distribution of parameters have been used to assess the model adequacy and

  10. Satellite-Based Assessment of Sediment Transport, Distribution and Resuspension Associated with the Atchafalaya River Discharge Plume (United States)

    Walker, Nan; Roberts, Harry; Stone, Gregory; Bentley, Samuel; Huh, Oscar; Sheremet, Alexandru; Rouse, Larry; Inoue, Masamichi; Welsh, Susan; Hsu, S. A.


    Tbe Atchafalaya River discharges over 80 x 10(exp 6) tons of sediment annually onto the broad shallow continental shelf of central and western Louisiana. Satellite imagery from the NOAA AVHRR and Terra MODIS are used in this paper to quantify suspended sediment concentrations and to assess sediment transport processes along the Louisiana shelf under varying conditions of river discharge and wind forcing. The image data reveal the maim sources of sediment, direction of transport amd regional extent of wind-wave resuspension. The prevailing easterly winds transport much of the suspended sediments westward toward the Chernier Plain in a well-defined mud stream. Westerly flow rates of 25-50 cm/s (21-43 km per day) have been measured, yielding a transit time of about 1.5-2.5 days from the mouth of Atchafalaya Bay to the Chernier Plain. Progradation rates along the Chernier Plain coast reach 50 m per year. The westward-flowing Atchafalaya "mud stream" is rapidly disrupted by westerly winds and northerly winds, which accompany frequent winter storms and less frequent tropical storms or hurricanes. During these events, the coastal current reverses and sediments are rapidly transported out of Atchafalaya Bay and offshore where substantial sedimentary deposits can also be found. Offshore sediment fluxes during storm events, in combination with wind-wave resuspension, can result in surface sediment "plumes" extending 70 km offshore and 150 km alongshore. Field measurements of suspended sediment concentrations, current and wind velocities, and directions are used to assess sediment transport processes on the shelf. These combined processes are extending the pro-delta deposits of the Atchafalaya-Wax Lake delta complex far onto the continental shelf and supplying sediments for a renewal era of progradation along tbe downdrift Chernier Plain coast.

  11. Flocculation Settling Dynamics of Natural Cohesive Suspended Sediments: "Floccin' Across the USA!" (United States)

    Manning, A. J.; Schoellhamer, D. H.; Mehta, A. J.; Schladow, G.; Monismith, S. G.; Huang, I. B.; Kuwabara, J. S.; Carter, J. L.; Sheremet, A.; Parsons, D. R.; Whitehouse, R. J. S.; Todd, D.; Benson, T.; Spearman, J.


    Many coastal and inland waterways are dominated by muddy sediments; comprising a mixture of clay minerals and various types of organic matter. When cohesive sediment is entrained into suspension, the particles tend to flocculate. Flocs are less dense, but faster settling than their constituent particles thus affecting their depositional characteristics. As flocs grow, their effective densities generally decrease, but their settling rates rise due to the Stokes' Law relationship. Flocculation effects become even more complex when purely cohesive sediments are mixed with different ratios of non-cohesive sediments, and if biological activity (e.g., exudate production) affects the resultant cohesion. Developing instrumentation that can provide key physical and dynamical data on depositional rates of flocculating sediments is extremely important in advancing our understanding of natural flocculation processes. Complementary qualitative and quantitative data improve our understanding of the depositional and aggregational physical processes through parameterization. This presentation will demonstrate recent advances in the study of the flocculation process through the use of video image technology. One such device pioneered at HR Wallingford, and implemented with co-authors, is the high-resolution floc video camera, LabSFLOC - Laboratory Spectral Flocculation Characteristics (developed by Prof. Manning). LabSFLOC can observe (directly or indirectly) floc spectral physical properties, including: floc size, settling velocity, effective density, porosity, shape, mass, and settling flux (using controlled volume referencing). These data are highly desirable for sediment transport modelers. Examples of floc measurements from locations in estuaries, tidal lagoons, river deltas, and lakes from locations across the US will be presented. In addition, we will demonstrate how video floc data can be used to parameterize floc settling characteristics for use in modeling.

  12. Mathematical simulation of sediment and contaminant transport in surface waters. Annual report, October 1977--September 1978

    International Nuclear Information System (INIS)

    Onishi, Y.; Arnold, E.M.; Serne, R.J.; Cowan, C.E.; Thompson, F.L.; Mayer, D.W.


    Various pathways exist for exposure of humans and biota to radioactive materials released from nuclear facilities. Hydrologic transport (liquid pathway) is one element in the evaluation of the total radiation dose to man. Mathematical models supported by well-planned field data collection programs can be useful tools in assessing the hydrologic transport and ultimate fate of radionuclides. Radionuclides with high distribution coefficients or radionuclides in surface waters with high suspended sediment concentrations are, to a great extent, adsorbed by river and marine sediments. Thus, otherwise dilute contaminants are concentrated. Contaminated sediments may be deposited on the river and ocean beds creating a significant pathway to man. Contaminated bed sediment in turn may become a long-term source of pollution through desorption and resuspension. In order to assess migration and accumulation of radionuclides in surface waters, mathematical models must correctly simulate essential mechanisms of radionuclide transport. The objectives of this study were: (1) to conduct a critical review of (a) radionuclide transport models as well as sediment transport and representative water quality models in rivers, estuaries, oceans, lakes, and reservoirs, and (b) adsorption and desorption mechanisms of radionuclides with sediments in surface waters; (2) to synthesize a mathematical model capable of predicting short- and long-term transport and accumulation of radionuclides in marine environments

  13. Impact of sound attenuation by suspended sediment on ADCP backscatter calibrations

    NARCIS (Netherlands)

    Sassi, M.G.; Hoitink, A.J.F.; Vermeulen, B.


    Although designed for velocity measurements, acoustic Doppler current profilers (ADCPs) are widely being used to monitor suspended particulate matter in rivers and in marine environments. To quantify mass concentrations of suspended matter, ADCP backscatter is generally calibrated with in situ

  14. Longshore sediment transport at Golden Sands (Bulgaria

    Directory of Open Access Journals (Sweden)

    Hristo Nikolov


    Full Text Available The paper presents the results of studies on the qualitative and quantitative features of the littoral drift at Golden Sands (Bulgaria, carried out jointly by Polish and Bulgarian researchers. The mathematical modelling of physical coastal processes took wave transformation (wave diffraction and refraction; the effects of shoaling and wave breaking and longshore sediment transport into account. The computations were carried out for the mean statistical annual wave climate, determined on the basis of IO BAS wave data, simulated using the WAM method from long-term Black Sea wind data. The results of sediment transport computations clearly show that its direction off the Golden Sands shore is from north to south.

  15. Sediment transport drives tidewater glacier periodicity. (United States)

    Brinkerhoff, Douglas; Truffer, Martin; Aschwanden, Andy


    Most of Earth's glaciers are retreating, but some tidewater glaciers are advancing despite increasing temperatures and contrary to their neighbors. This can be explained by the coupling of ice and sediment dynamics: a shoal forms at the glacier terminus, reducing ice discharge and causing advance towards an unstable configuration followed by abrupt retreat, in a process known as the tidewater glacier cycle. Here we use a numerical model calibrated with observations to show that interactions between ice flow, glacial erosion, and sediment transport drive these cycles, which occur independent of climate variations. Water availability controls cycle period and amplitude, and enhanced melt from future warming could trigger advance even in glaciers that are steady or retreating, complicating interpretations of glacier response to climate change. The resulting shifts in sediment and meltwater delivery from changes in glacier configuration may impact interpretations of marine sediments, fjord geochemistry, and marine ecosystems.The reason some of the Earth's tidewater glaciers are advancing despite increasing temperatures is not entirely clear. Here, using a numerical model that simulates both ice and sediment dynamics, the authors show that internal dynamics drive glacier variability independent of climate.

  16. Numerical simulation of sediment transport from Ba Lat Mouth and the process of coastal morphology

    International Nuclear Information System (INIS)

    Chung, Dang Huu


    This paper presents an application of a 3D numerical model to simulate one vertical layer sediment transport and coastal morphodynamical process for the Hai Hau coastal area located in the north of Vietnam, where a very large amount of suspended sediment is carried into the sea from Ba Lat Mouth every year. Four simulations are based on the real data of waves supplied by the observation station close to Ba Lat Mouth. The conditions of wind and suspended sand concentration at Ba Lat Mouth are basically assumed from practice. The computed results show that the hydrodynamic factors strongly depend on the wind condition and these factors govern the direction and the range of suspended sand transport, especially in the shallow-water region. In the deep-water region this influence is not really clear when the wind force is not strong enough to modify the tidal current. In the area close to Ba Lat Mouth the flow velocity is very large with the maximum flood flow about 2.6 m s −1 and the maximum ebb flow about 1 m s −1 at the mouth, and this is one of the reasons for strong erosion. In the case of tidal flow only, the suspended sand concentration decreases resulting in local deposition. Therefore, the area influenced by suspended transport is small, about 12 km from the mouth. In the condition of wind and waves, the suspended sand transport reaches the end of the computation area within a few days, especially the cases with wind from the north-east-north. Through these simulation results, a common tendency of sediment movement from the north to the south is specified for the Hai Hau coastal area. In addition, the results also show that the coast suffers from strong erosion, especially the region near Ba Lat Mouth. From the simulation results it can be seen that the movement of the Red River sand along the Vietnamese coast is quite possible, which is an answer to a long-standing question. Furthermore, although the suspended sediment concentration is quite large, it is

  17. RANS-based simulation of turbulent wave boundary layer and sheet-flow sediment transport processes

    DEFF Research Database (Denmark)

    Fuhrman, David R.; Schløer, Signe; Sterner, Johanna


    with bed and suspended load descriptions, the latter based on an unsteady turbulent-diffusion equation, for simulation of sheet-flow sediment transport processes. In addition to standard features common within such RANS-based approaches, the present model includes: (1) hindered settling velocities at high...... of a number of local factors important within cross-shore wave boundary layer and sediment transport dynamics. The hydrodynamic model is validated for both hydraulically smooth and rough conditions, based on wave friction factor diagrams and boundary layer streaming profiles, with the results in excellent...... agreement with experimental and/or previous numerical work. The sediment transport model is likewise validated against oscillatory tunnel experiments involving both velocity-skewed and acceleration-skewed flows, as well as against measurements beneath real progressive waves.Model capabilities are exploited...

  18. Near-bed observations of high-concentration sediment transport in the Changjiang Estuary (United States)

    Zhou, Z.; Ge, J.; Ding, P.


    The North Passage, the core of turbidity maximum in the Changjiang Estuary, is now under the strong sedimentation due to the abundant sediment supply from the upstream Changjiang River and the river-tide interacted dynamics. Recent studies suggested that strong siltation could be attributed to bottom high-concentration sediment transport, which however is very difficult to be detected and observed by vessel-anchored survey methods. To better understand the mechanisms of sediment transport and deposition in the channel region of the North Passage and its adjacent areas, we conducted continuous field observations which covered spring and neap tide period in the wintertime of 2016, the summertime of 2015 and 2017, focusing on near-bottom sediment transport. Tripods mounted with multiple instruments, including up-looking and down-looking Acoustic Doppler Current Profilers(ADCP), Vector Current Meter(ADV), Optical Backscatter Sensor(OBS), ASM, ALEC and RBR were used to observe the near-bottom physical process and its induced sediment dynamics. Results of these observations clearly described the current-wave-sediment interaction, which produced different patterns of bottom mud suspension at different tripods. Both hydrodynamic features and suspended sediment showed variations between spring and neap tide. Taking data of 2016 as an example, averaged suspended sediment concentration(SSC) at two tripods was 1.52 g/L and 2.13 g/L during the neap tide, 4.51 g/L and 5.75 g/L with the peak value reaching 25 g/L during the spring tide. At the tripod which was closer to the channel region, three peaks of SSC during the spring tide occurred near the flood slack with notable salinity increase, indicating the impact of saltwater intrusion on the bottom hydrodynamics. The results showed the occurrence of high-concentration suspended sediment was probably related to combined effects of bottom salinity intrusion, turbulent kinetic energy(TKE) and local stratification due to density

  19. Lateral and vertical heterogeneity of flow and suspended sediment characteristics during a dam flushing event, in high velocity conditions (United States)

    Antoine, Germain; Cazilhac, Marine; Monnoyer, Quentin; Jodeau, Magali; Gratiot, Nicolas; Besnier, Anne-Laure; Henault, Fabien; Le Brun, Matthieu


    The dynamic of suspended sediments in highly turbulent and concentrated flow is an important issue to better predict the sediment propagation along mountain rivers. In such extreme environments, the spatial and temporal variability of hydraulic and sediment parameters are difficult to measure: the flow velocity and the suspended sediment concentration (SSC) could be high (respectively several m/s and g/l) and rapidly variable. Simple methods are commonly used to estimate water discharge and mean or punctual SSC. But no method has been used successfully in a mountain river to estimate during a whole event the spatial distribution of flow velocity and SSC, as well as sediment parameters like grain size or settling velocity into a river cross section. This leads to these two questions: in such conditions, can we calculate sediment fluxes with one sediment concentration measurement? How can we explain the spatial heterogeneity of sediment characteristics? In this study, we analyze sampled data from a very well instrumented river reach in the Northern French Alps: the Arc-Isère River system. This gravel-bed river system is characterized by large concentrations of fines sediments, coming from the highly erodible mountains around. To control the hydraulic, sedimentary and chemical parameters from the catchment head, several gauging stations have been established since 2006. Especially, several measurements are usually done during the flushing of the dams located on the upper part of the river. During the flushing event of June 2014, we instrumented the gauging station located just upstream the confluence between the Isere and the Arc River, at the outlet of the Arc River watershed. ADCP measurements have been performed to estimate the spatial distribution of the flow velocity (up to 3 m/s), and turbidimeters and automatic samplers have been used to estimate the spatial distribution of the SSC into the cross section (up to 6 g/l). These samples have been directly analyzed

  20. The Response of Suspended Sediment, Turbidity, and Velocity to Historical Alterations of the Missouri River (United States)

    Blevins, Dale W.


    The heavy sediment load and large amounts of floating debris generated by the constantly caving banks of the Missouri River was documented in the first written description of the river by Father Jacques Marquette in 1673 as he approached the mouth of the Missouri River from the upper Mississippi River: '[We]' heard the noise of a rapid, into which we were about to run. I have seen nothing more dreadful. An accumulation of large and entire trees, branches, and floating islands, was issuing from the mouth of the river Pekitanoui (Missouri River), with such impetuosity that we could not without great danger risk passing through it. So great was its agitation that the water was so very muddy, and could not become clear.' However, large changes in suspended sediment and turbidity in the lower Missouri River below Gavins Point Dam have occurred in response to extensive structural changes that have been imposed on the Missouri River and its watershed during the last two centuries. Efforts to shape the channel, remove snags and sawyers, dredge shallows, and stabilize banks for navigation began as early as 1838 ( , Chittenden, 1903). However, bank stabilization efforts were sporadic and scattered in comparison to large scale changes that occurred after 1929. In the early 1930s the numerous small channels were combined into a single-fixed channel with 4,745 stone and wood-pile dikes, 3,371 dike extensions, streambank protection works on concave banks, man-made cutoffs, the closing of chutes with dikes, the removal of snags, and dredging (Keown and others, 1981). The resulting navigation channel was 6-ft (feet) deep by 200-ft wide and was expanded to 9 by 300 ft in the 1950s and early 1960s. Construction of six dams was started in 1933 and their reservoirs were filled by 1967. Three of these reservoirs are among the five largest in the United States. Nearly one-third of the Missouri River is now submerged below these massive

  1. Sedimentation and transportation of mud rock material (United States)

    Lin, J.; Ochiai, S.


    This research focuses on the transportation and sedimentation of mud rock slope at Niupu, southern Taiwan. The main purpose of this research is trying to identify the mechanism of erosion and sedimentation rate of the mud rock from the slope into the lake. By using regular sonar surveying and rainfall data, it is possible to identify a high erosion rate on mud rock area. The cementation of Miocene mud rock is loose and slope at 40-45 degree which is highly sensitive to the rainfall. It is also vulnerable to the erosion processes. There are some interesting characters related to the observation and surveying. The erosion processes are highly related to amounts of rainfall. When there is typhoon, tropical storm, there is high erosion. The erosion could occur when there is rainfall more than 10 mm/event and the surface of the mud rock could be incised up to 3 cm after 30 mm rainfall. The sedimentation rate could also as high as 0.5 m when there are two typhoons which attacked to this area within three months. This research also demonstrates that the high erosion on mud rock area will generate high sedimentation and high denudation rate. However the comparison of the rate of erosion and deposition is identified in this presentation. For hazard mitigation purpose, it is necessary to reduce the bared mud rock slope area to prevent the further erosion.

  2. Mathematical simulation of sediment and radionuclide transport in estuaries

    International Nuclear Information System (INIS)

    Onishi, Y.; Trent, D.S.


    The finite element model LFESCOT (Flow, Energy, Salinity, Sediment and Contaminant Transport Model) was synthesized under this study to simulate radionuclide transport in estuaries to obtain accurate radionuclide distributions which are affected by these factors: time variance, three-dimensional flow, temperature, salinity, and sediments. Because sediment transport and radionuclide adsorption/desorption depend strongly on sizes or types of sediments, FLESCOT simulates sediment and a sediment-sorbed radionuclide for the total of three sediment-size fractions (or sediment types) of both cohesive and noncohesive sediments. It also calculates changes of estuarine bed conditions, including bed elevation changes due to sediment erosion/deposition, and three-dimensional distributions of three bed sediment sizes and sediment-sorbed radionuclides within the bed. Although the model was synthesized for radionuclide transport, it is general enough to also handle other contaminants such as heavy metals, pesticides, or toxic chemicals. The model was checked for its capability for flow, water surface elevation change, salinity, sediment and radionuclide transport under various simple conditions first, confirming the general validity of the model's computational schemes. These tests also revealed that FLESCOT can use large aspect ratios of computational cells, which are necessary in handling long estuarine study areas. After these simple tests, FLESCOT was applied to the Hudson River estuary between Chelsea and the mouth of the river to examine how well the model can predict radionuclide transport through simulating tidally influenced three-dimensional flow, salinity, sediment and radionuclide movements with their interactions

  3. Modelling sediment clasts transport during landscape evolution (United States)

    Carretier, Sébastien; Martinod, Pierre; Reich, Martin; Godderis, Yves


    Over thousands to millions of years, the landscape evolution is predicted by models based on fluxes of eroded, transported and deposited material. The laws describing these fluxes, corresponding to averages over many years, are difficult to prove with the available data. On the other hand, sediment dynamics are often tackled by studying the distribution of certain grain properties in the field (e.g. heavy metals, detrital zircons, 10Be in gravel, magnetic tracers). There is a gap between landscape evolution models based on fluxes and these field data on individual clasts, which prevent the latter from being used to calibrate the former. Here we propose an algorithm coupling the landscape evolution with mobile clasts. Our landscape evolution model predicts local erosion, deposition and transfer fluxes resulting from hillslope and river processes. Clasts of any size are initially spread in the basement and are detached, moved and deposited according to probabilities using these fluxes. Several river and hillslope laws are studied. Although the resulting mean transport rate of the clasts does not depend on the time step or the model cell size, our approach is limited by the fact that their scattering rate is cell-size-dependent. Nevertheless, both their mean transport rate and the shape of the scattering-time curves fit the predictions. Different erosion-transport laws generate different clast movements. These differences show that studying the tracers in the field may provide a way to establish these laws on the hillslopes and in the rivers. Possible applications include the interpretation of cosmogenic nuclides in individual gravel deposits, provenance analyses, placers, sediment coarsening or fining, the relationship between magnetic tracers in rivers and the river planform, and the tracing of weathered sediment.

  4. Streamflow, suspended-sediment, and soil-erosion data from Kaulana and Hakioawa watersheds, Kaho'olawe, Hawai'i, (United States)

    Izuka, Scot K.; Abbott, Lyman L.


    Various events over the last two centuries have destroyed the vegetation and caused rapid soil erosion on large areas of the small, arid, windy tropical shield-volcano island of Kaho`olawe, Hawai`i. These activities were largely halted in the 1990s, and efforts have been made to restore the island's vegetation in order to stem erosion. In 2003, the Kaho`olawe Island Reserve Commission (KIRC) began restoration efforts using native vegetation. In 2006 to 2010, the U.S. Geological Survey (USGS), in cooperation with the KIRC, monitored streamflow, fluvial suspended-sediment transport, and erosion rates in the Hakioawa and Kaulana watersheds on northeastern Kaho`olawe to provide information needed to assess the effectiveness of restoration efforts. This report presents the results from this monitoring. Results.-Hakioawa and Kaulana gulches were dry about 90 percent of the time during the monitoring period; mean annual flow was 0.06 ft3/s at Hakioawa Gulch gage and 0.01 ft3/s at the Kaulana Gulch gage. For the period when the sediment gages on both gulches were operating concurrently (October 2007 to September 2009), sediment discharge was higher from Hakioawa Gulch than from Kaulana Gulch. The annual suspended-sediment loads for the concurrent period averaged 1,880 tons at the Hakioawa Gulch gage and 276 tons at the Kaulana Gulch gage. Of the 77 erosion-monitoring sites in the Hakioawa and Kaulana watersheds, 50 had overall rates of change indicating erosion for the monitoring period, ranging from -1 to -10 mm/yr and averaging -3 mm/yr. Seven sites had rates of change indicating overall deposition, ranging from 1 to 15 mm/yr and averaging 5 mm/yr. Twenty had rates of change below detection (less than ?1 mm/yr). The average rate of change for the 26 sites in areas that have undergone restoration by the KIRC was below the detection limit of the erosion-monitoring method. In comparison, the 51 sites in nonrestoration areas averaged -2 mm/y. Both of these averages, however

  5. Baseline to Evaluate Off-Site Suspended Sediment-Related Mining Effects in the Alto Tajo Natural Park, Spain


    Zapico, Ignacio; Laronne, J. B.; Martín Moreno, Cristina; Martín Duque, J. F.; Ortega, Ana Isabel; Sánchez Castillo, L.


    Mining is a human activity with considerable environmental impact. To evaluate such impacts, international laws require undertaking local studies based on direct sampling to establish baseline conditions of parameters modified by human activities. Mining takes place near the Alto Tajo Natural Park, where a suspended sediment concentration (SSC) baseline is required to determine whether mining affects water quality. To this end, we have monitored the Tajo River and its tributary the Tajuelo fo...

  6. Comparison of three persulfate digestion methods for total phosphorus analysis and estimation of suspended sediments

    International Nuclear Information System (INIS)

    Dayton, Elizabeth Ann; Whitacre, Shane; Holloman, Christopher


    As a result of impairments to fresh surface water quality due to phosphorus enrichment, substantial research effort has been put forth to quantify agricultural runoff phosphorus as related to on-field practices. While the analysis of runoff dissolved phosphorus is well prescribed and leaves little room for variability in methodology, there are several methods and variations of sample preparation reagents as well as analysis procedures for determining runoff total phosphorus. Due to the variation in methodology for determination of total phosphorus and an additional laboratory procedure required to measure suspended solids, the objectives of the current study are to i. compare the performance of three persulfate digestion methods (Acid Persulfate, USGS, and Alkaline Persulfate) for total phosphorus percent recovery across a wide range of suspended sediments (SS), and ii. evaluate the ability of using Al and/or Fe in digestion solution to predict SS as a surrogate to the traditional gravimetric method. Percent recovery of total phosphorus was determined using suspensions prepared from soils collected from 21 agricultural fields in Ohio. The Acid Persulfate method was most effective, with an average total phosphorus percent recovery of 96.6%. The second most effective method was the USGS with an average total phosphorus recovery of 76.1%. However, the Alkaline Persulfate method performed poorly with an average 24.5% total phosphorus recovery. As a result application of Alkaline Persulfate digestion to edge of field monitoring may drastically underestimated runoff total phosphorus. In addition to excellent recovery of total phosphorus, the Acid Persulfate method combined with analysis of Al and Fe by inductively coupled plasma atomic emission spectrometry provides a robust estimate of total SS. Due to the large quantity of samples that can result from water quality monitoring, an indirect measure of total SS could be very valuable when time and budget constraints limit

  7. Sediment Transport Time Scales and Trapping Efficiency in a Tidal River (United States)

    Ralston, David K.; Geyer, W. Rockwell


    Observations and a numerical model are used to characterize sediment transport in the tidal Hudson River. A sediment budget over 11 years including major discharge events indicates the tidal fresh region traps about 40% of the sediment input from the watershed. Sediment input scales with the river discharge cubed, while seaward transport in the tidal river scales linearly, so the tidal river accumulates sediment during the highest discharge events. Sediment pulses associated with discharge events dissipate moving seaward and lag the advection speed of the river by a factor of 1.5 to 3. Idealized model simulations with a range of discharge and settling velocity were used to evaluate the trapping efficiency, transport rate, and mean age of sediment input from the watershed. The seaward transport of suspended sediment scales linearly with discharge but lags the river velocity by a factor that is linear with settling velocity. The lag factor is 30-40 times the settling velocity (mm s-1), so transport speeds vary by orders of magnitude from clay (0.01 mm s-1) to coarse silt (1 mm s-1). Deposition along the tidal river depends strongly on settling velocity, and a simple advection-reaction equation represents the loss due to settling on depositional shoals. The long-term discharge record is used to represent statistically the distribution of transport times, and time scales for settling velocities of 0.1 mm s-1 and 1 mm s-1 range from several months to several years for transport through the tidal river and several years to several decades through the estuary.

  8. Use of an ADCP to compute suspended-sediment discharge in the tidal Hudson River, New York (United States)

    Wall, Gary R.; Nystrom, Elizabeth A.; Litten, Simon


    Acoustic Doppler current profilers (ADCPs) can provide data needed for computation of suspended-sediment discharge in complex river systems, such as tidal rivers, in which conventional methods of collecting time-series data on suspended-sediment concentration (SSC) and water discharge are not feasible. Although ADCPs are not designed to measure SSC, ADCP data can be used as a surrogate under certain environmental conditions. However, the software for such computation is limited, and considerable post-processing is needed to correct and normalize ADCP data for this use. This report documents the sampling design and computational procedure used to calibrate ADCP measures of echo intensity to SSC and water velocity to discharge in the computation of suspended-sediment discharge at the study site on the Hudson River near Poughkeepsie, New York. The methods and procedures described may prove useful to others doing similar work in different locations; however, they are specific to this study site and may have limited applicability elsewhere.

  9. New method of suspended sediment flux collection in the estuarine environment using bi-directional time-integrated mass-flux samplers (TIMs) (United States)

    Monbureau, E.; Elliott, E. A.; Walters, G.; McKee, B. A.; Rodriguez, A. B.


    Understanding the source and abundance of sediment transported within tidal creeks is essential for studying the connectivity between coastal watersheds and estuaries under conditions of changing land use, storminess and sea-level rise. Furthermore, analysis of the fine grained suspended sediment load (SSL) carried through the system is critical in our understanding of nutrient and contaminant transport, human-induced change, and the effects of climate. Unfortunately traditional methods of SSL collection, including instantaneous measurements and automatic samplers, can be labor intensive, expensive and are often inadequate for geochemical analysis. In estuaries this issue is even more pronounced, due to tidal bi-directional flow. This study tests the efficacy of a modification to an established uni-directional time-integrated sediment sampler (TIMs) design. Our new bi-directional TIMs design utilizes a 'L' shaped outflow tube to collect sediment uniquely in each direction of tidal flow. Laboratory flume experiments using dye and particle image velocimetry (PIV) are used to characterize the flow within the collector, specifically, to quantify the settling velocities and identify the stagnation points. Further laboratory tests of chemically dispersed sediment indicate that bi-directional TIMs capture nearly all incoming particles greater than 4 μm across a range of flow velocities. Field trials were employed in two distinct sampling locations within the tidal zone. Samples of single time point SSL were collected over a four day period and compared to sediment collected by the bi-directional TIMs over the same time frame. Particle size composition from the bi-directional TIMs were representative of the array of single time point samples, but yielded greater mass and proved to be more representative of the overall tidal flux. This work proves the efficacy of the modified bi-directional TIMs design, offering a novel tool for collection of SSL in the tidally dominated

  10. Sediment transport in the aftermath of the 2008 Wenchuan earthquake: constraints from landslide mapping, photo-sieving and reservoir accumulation (United States)

    Li, G.; West, A. J.; Hammond, D. E.; Xiao, Z.; Okaya, D. A.; Densmore, A. L.; Hilton, R. G.; Jin, Z.; Zhang, F.; Wang, J.


    Understanding post-seismic sediment transport is important for assessing crustal mass redistribution by earthquakes and for managing seismically-induced geohazards, including channel aggradation and flooding. The 2008 Wenchuan earthquake (Mw 7.9) triggered over 60,000 landslides in the Longmen Shan range of the eastern Tibetan Plateau. Records from hydrometric gauging show enhanced regional suspended sediment fluxes following the earthquake, resulting from evacuation of the landslide sediment (Wang et al., in revision). In addition to the insights into suspended sediment dynamics from gauging stations, this large-magnitude seismic event provides an opportunity to study bedload sediment transport after a large earthquake. Here we present primary results from a comprehensive investigation of the Min Jiang river system following the Wenchuan earthquake. Using a landslide inventory map (Li et al., 2014) and a DEM-based river network, we mapped landslide-river network connectivity. With photo-sieving techniques, we estimated the grain size distribution of medium-grained (mm to cm scale) landslide deposits. These data provide constraints on sediment sources. The mass of sediment in transport has been estimated from river sediment quartz 10Be measurements (West et al., 2014), supplemented here by constraints from rates of sediment infill in a downstream reservoir, determined by bathymetric profiling and analysis of sediment cores. Together with hydrometric data, this dataset provides the basic parameters for modeling sediment transport in the Min Jiang river system after the Wenchuan earthquake and promises insight into the mechanisms controlling post-earthquake sediment transport. References Li et al., 2014 , Geochem. Geophys. Geosyst., 15, 833-844, Wang et al., in revision West et al., 2014, Earth Planet Sc. Lett., 396, 143-153

  11. Modeling sediment transport after ditch network maintenance of a forested peatland (United States)

    Haahti, K.; Marttila, H.; Warsta, L.; Kokkonen, T.; Finér, L.; Koivusalo, H.


    Elevated suspended sediment (SS) loads released from peatlands after drainage operations and the resulting negative effect on the ecological status of the receiving water bodies have been widely recognized. Understanding the processes controlling erosion and sediment transport within the ditch network forms a prerequisite for adequate sediment control. While numerous experimental studies have been reported in this field, model based assessments are rare. This study presents a modeling approach to investigate sediment transport in a peatland ditch network. The transport model describes bed erosion, rain-induced bank erosion, floc deposition, and consolidation of the bed. Coupled to a distributed hydrological model, sediment transport was simulated in a 5.2 ha forestry-drained peatland catchment for 2 years after ditch cleaning. Comparing simulation results to measured SS concentrations suggested that the loose peat material, produced during excavation, contributed markedly to elevated SS concentrations immediately after ditch cleaning. Both snowmelt and summer rainstorms contributed critically to annual loads. Springtime peat erosion during snowmelt was driven by ditch flow whereas during summer rainfalls, bank erosion by raindrop impact was identified as an important process. Relating modeling results to observed spatial topographic changes in the ditch network was challenging and the results were difficult to verify. Nevertheless, the model has potential to identify risk areas for erosion. The results demonstrate that modeling is effective in separating the importance of different processes and complements pure experimental approaches. Modeling results can aid planning and designing efficient sediment control measures and guide the focus of experimental studies.

  12. California coast nearshore processes study. [nearshore currents, sediment transport, estuaries, and river discharge (United States)

    Pirie, D. M.; Steller, D. D. (Principal Investigator)


    The author has identified the following significant results. Large scale sediment plumes from intermittent streams and rivers form detectable seasonal patterns on ERTS-1 imagery. The ocean current systems, as plotted from three California coast ERTS mosaics, were identified. Offshore patterns of sediment in areas such as the Santa Barbara Channel are traceable. These patterns extend offshore to heretofore unanticipated ranges as shown on the ERTS-1 imagery. Flying spot scanner enhancements of NASA tapes resulted in details of subtle and often invisible (to the eye) nearshore features. The suspended sediments off San Francisco and in Monterey Bay are emphasized in detail. These are areas of extremely changeable offshore sediment transport patterns. Computer generated contouring of radiance levels resulted in maps that can be used in determining surface and nearsurface suspended sediment distribution. Tentative calibrations of ERTS-1 spectral brightness against sediment load have been made using shipboard measurements. Information from the combined enhancement and interpretation techniques is applicable to operational coastal engineering programs.

  13. Transport and deposition of plutonium in the ocean: Evidence from Gulf of Mexico sediments

    International Nuclear Information System (INIS)

    Scott, M.R.; Salter, P.F.; Halverson, J.E.


    A study of sediments in the Gulf of Mexico shows dramatic gradients in Pu content and isotope ratios from the continental shelf to the Sigsbee Abyssal Plain. In terms of predicted direct fallout inventory of Pu, one shelf core contains 745% of the predicted inventory, while abyssal plain sediments contain only 15-20% of the predicted value. Absolute Pu concentrations of shelf sediments are also conspicuously high, up to 110 dpm/kg, compared to 13.5 dpm/kg in Mississippi River suspended sediment. There is no evidence of Pu remobilization in Gulf of Mexico shelf sediments, based on comparison of Pu profiles with Mn/Al and Fe/Al profiles. Horizontal transport of fallout nuclides from the open ocean to removal sites in ocean margin sediments is concluded to be the source of both the high concentrations and high inventories of Pu reported here. The shelf sediments show 240 Pu/ 239 Pu ratios close to 0.179, the average stratospheric fallout value, but the ratios decrease progressively across the Gulf to low values of 0.06 in abyssal plain sediments. The source of low-ratio Pu in deep-water sediments may be debris from low yield tests transported in the troposphere. Alternatively, it may represent a fraction of the Pu from global stratospheric fallout which has been separated in the water column from the remainder of the Pu in the ocean. In either case, the low-ratio material must have been removed rapidly to the sea floor where it composes a major fraction of the Pu in abyssal plain sediments. Pu delivered by global atmospheric fallout from the stratosphere has apparently remained for the most part in the water or has been transported horizontally and removed into shallow-water sediments. (orig.)

  14. Enhancement of toxic effects of phenanthrene to Daphnia magna due to the presence of suspended sediment. (United States)

    Zhang, Xiaotian; Xia, Xinghui; Dong, Jianwei; Bao, Yimeng; Li, Husheng


    In the present work, the influences of suspended sediment (SPS) on the toxic effects of phenanthrene (PHE), one kind of polycyclic aromatic hydrocarbons, to Daphnia magna was studied using a dialysis bag simulation system, which equalized the freely dissolved concentration of PHE between outside the dialysis bag in the presence of SPS and inside the dialysis bag in the absence of SPS. The immobilization and total superoxide dismutase (T-SOD) activity of Daphnia magna caused by PHE (0-0.8 mg L(-1)) were investigated under the influence of different SPS concentrations (0, 1, 3, 5 g L(-1)) during a 96 h-exposure. The results showed that, compared to the absence of SPS, the presence of SPS (1-5 g L(-1)) increased the immobilization of Daphnia magna by 1.6-2.7 times when the freely dissolved concentration of PHE was identical in both systems. The inhibition of T-SOD activity of Daphnia magna by PHE was significantly greater in the presence of SPS than in the absence of SPS (pDaphnia magna. The bioavailable fraction of PHE sorbed on SPS ranged from 10.1% to 22.7%, and the contribution of PHE sorbed on SPS to the immobilization caused by total PHE in the exposure system increased with SPS concentration, with the contribution ratio increasing from 36.7% to 57.7% when SPS concentration increased from 1 to 5 g L(-1). This study suggests that only considering the concentrations of hydrophobic organic compounds in the water phase may underestimate their toxicity; and the hydrophobic organic compounds sorbed on SPS should not be ignored in assessment of water quality and the establishment of water quality standard in the future. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Comparison of environmental forcings affecting suspended sediments variability in two macrotidal, highly-turbid estuaries (United States)

    Jalón-Rojas, Isabel; Schmidt, Sabine; Sottolichio, Aldo


    The relative contribution of environmental forcing frequencies on turbidity variability is, for the first time, quantified at seasonal and multiannual time scales in tidal estuarine systems. With a decade of high-frequency, multi-site turbidity monitoring, the two nearby, macrotidal and highly-turbid Gironde and Loire estuaries (west France) are excellent natural laboratories for this purpose. Singular Spectrum Analyses, combined with Lomb-Scargle periodograms and Wavelet Transforms, were applied to the continuous multiannual turbidity time series. Frequencies of the main environmental factors affecting turbidity were identified: hydrological regime (high versus low river discharges), river flow variability, tidal range, tidal cycles, and turbulence. Their relative influences show similar patterns in both estuaries and depend on the estuarine region (lower or upper estuary) and the time scale (multiannual or seasonal). On the multiannual time scale, the relative contribution of tidal frequencies (tidal cycles and range) to turbidity variability decreases up-estuary from 68% to 47%, while the influence of river flow frequencies increases from 3% to 42%. On the seasonal time scale, the relative influence of forcings frequencies remains almost constant in the lower estuary, dominated by tidal frequencies (60% and 30% for tidal cycles and tidal range, respectively); in the upper reaches, it is variable depending on hydrological regime, even if tidal frequencies are responsible for up 50% of turbidity variance. These quantifications show the potential of combined spectral analyses to compare the behavior of suspended sediment in tidal estuaries throughout the world and to evaluate long-term changes in environmental forcings, especially in a context of global change. The relevance of this approach to compare nearby and overseas systems and to support management strategies is discussed (e.g., selection of effective operation frequencies/regions, prediction of the most

  16. State-of-the-art in modeling solute and sediment transport in rivers

    International Nuclear Information System (INIS)

    Sayre, W.W.


    This overview is structured around a comprehensive general model based on the conservation of mass principle as applied to dissolved and particulate constituents in rivers, with a few restricted but more specific examples that illustrate the state-of-the-art in modeling typical physical, chemical, and biological processes undergone by selected constituents in rivers. These examples include: simplified one- and two-dimensional formulations focusing on the hydrodynamic advection and dispersion mechanisms; a two-dimensional biochemial oxygen demand-dissolved oxygen model; a one-dimensional polychlorinated biphenyl model that includes uptake and release of constituent by suspended sediment, and deposition and erosion of contaminated particles; and a one-dimensional sediment transport model that accounts for interactions between the flow and the bed, and is capable of tracking dispersing slugs of sediment through cycles of erosion, entrainment, transport in suspension and as bed load, and burial and storage in the bed

  17. Sediment transport along the Goa-north Karnataka Coast, western India

    Digital Repository Service at National Institute of Oceanography (India)

    Kunte, P.D.

    of sediment transport. Although sediment-transport direction is bi-directional, net major sediment transport is southward. The geomorphic study identified possible sediment sources and sinks. Contributions of sources and losses due to sinks are assessed...

  18. Purus River suspended sediment variability and contributions to the Amazon River from satellite data (2000-2015) (United States)

    Santos, Andre Luis Martinelli Real dos; Martinez, Jean Michel; Filizola, Naziano Pantoja; Armijos, Elisa; Alves, Luna Gripp Simões


    The Purus River is one of the major tributaries of Solimões River in Brazil, draining an area of 370,091 km2 and stretching over 2765 km. Unlike those of the other main tributaries of the Amazon River, the Purus River's sediment discharge is poorly characterized. In this study, as an alternative to the logistic difficulties and considering high monitoring costs, we report an experiment where field measurement data and 2700 satellite (MODIS) images are combined to retrieve both seasonal and interannual dynamics in terms of the Purus river sediment discharge near its confluence with the Solimões River. Field radiometric and hydrologic measurements were acquired during 18 sampling trips, including 115 surface water samples and 61 river discharge measurements. Remote sensing reflectance gave important results in the red and infrared levels. They were very well correlated with suspended sediment concentration. The values of R2 are greater than 0.8 (red band) and 0.9 (NIR band). A retrieval algorithm based on the reflectance in both the red and the infrared was calibrated using the water samples collected for the determination of the surface-suspended sediment concentration (SSS). The algorithm was used to calculate 16 years of SSS time series with MODIS images at the Purus River near its confluence with the Solimões River. Results from satellite data correlated with in situ SSS values validate the use of satellite data to be used as a tool to monitor SSS in the Purus River. We evidenced a very short and intense sediment discharge pulse with 55% of the annual sediment budget discharged during the months of January and February. Using river discharge records, we calculated the mean annual sediment discharge of the Purus River at about of 17 Mt·yr-1.

  19. Catch and Release: A dense, longitudinal array of water quality sondes reveals spatial and temporal complexities in suspended sediment flux (United States)

    Guilinger, J. J.; Crosby, B. T.


    Excessive suspended sediment in streams is one of the most common causes for industrial, ecological and recreational stream impairment in the US. Identifying the primary geomorphic or anthropogenic sources of sediment is a key step in the effective mitigation of impairment. This study seeks to identify sources of suspended sediment in an agriculturally impaired watershed, Marsh Creek, in southeast Idaho. We employ thirteen multi-parameter water quality sensors to simultaneously measure stage, turbidity, temperature and conductivity every 15 minutes over a full calendar year. Examined at both the event and annual scale, these data enable mass balance calculations for mainstem and tributary contributions. Revealed in this monitoring is an approximately eight-fold longitudinal increase in sediment flux over 74 km that is largely augmented by eroding mainstem banks in reaches with higher stream power in the lower 30 km, with less than 20% contributed from tributaries. Independent data confirming the bank source were acquired through cost-effective sediment fingerprinting using 15N and C:N signatures from potential soil endmembers. Additionally, Google Street View-type longitudinal imagery of banks was collected via a kayak survey to confirm the spatial extent and magnitude of bank erosion along Marsh Creek. These data converge on bank erosion as the primary source of fine sediment. Sediment load at various hierarchical temporal and spatial scales is impacted by in-stream storage and remobilization, especially over shorter timescales ranging from daily to seasonal periods. Once averaged over the annual scale, local, temporary in-channel storage is overcome and these data reveal source reaches that can be prioritized for restoration and mitigation projects.

  20. Assimilation of remote sensing observations into a sediment transport model of China's largest freshwater lake: spatial and temporal effects. (United States)

    Zhang, Peng; Chen, Xiaoling; Lu, Jianzhong; Zhang, Wei


    Numerical models are important tools that are used in studies of sediment dynamics in inland and coastal waters, and these models can now benefit from the use of integrated remote sensing observations. This study explores a scheme for assimilating remotely sensed suspended sediment (from charge-coupled device (CCD) images obtained from the Huanjing (HJ) satellite) into a two-dimensional sediment transport model of Poyang Lake, the largest freshwater lake in China. Optimal interpolation is used as the assimilation method, and model predictions are obtained by combining four remote sensing images. The parameters for optimal interpolation are determined through a series of assimilation experiments evaluating the sediment predictions based on field measurements. The model with assimilation of remotely sensed sediment reduces the root-mean-square error of the predicted sediment concentrations by 39.4% relative to the model without assimilation, demonstrating the effectiveness of the assimilation scheme. The spatial effect of assimilation is explored by comparing model predictions with remotely sensed sediment, revealing that the model with assimilation generates reasonable spatial distribution patterns of suspended sediment. The temporal effect of assimilation on the model's predictive capabilities varies spatially, with an average temporal effect of approximately 10.8 days. The current velocities which dominate the rate and direction of sediment transport most likely result in spatial differences in the temporal effect of assimilation on model predictions.

  1. Carbon and nitrogen stable isotopes in suspended matter and sediments from the Schelde Estuary

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.


    The C/N and stable C and N isotope ratios (delta(13)C, delta(15)N) of sedimentary and suspended particulate matter were determined in the Schelde Estuary. Suspended matter was divided into 2 to 5 size fractions by centrifugation. Four major pools of organic matter were recognized: riverine,

  2. A combined model of sediment production, supply and transport

    Directory of Open Access Journals (Sweden)

    M. Fujita


    Full Text Available In previous sediment-runoff models, the sediment production rates of mountain slopes, and the sediment supply rates to streams typically have been developed using empirical methods. A process-based model for sediment production and supply is, however, required for more exact simulations of sediment runoff. In this study, we develop a method to calculate the sediment production rate due to both freeze-thaw action and the sediment supply rate (i.e. erosion rate of talus. These numerical models were then connected to an existing sediment transport model. The integrated model presented here was applied to a small mountainous watershed. We found that the calculated sediment production rate was within the range of values typically observed for this region. Additionally, the estimated annual sediment discharge using the model agreed with observational results. Lastly, we found that the model can be used to qualitatively characterize typical features of the actual sediment routine in mountainous watersheds.

  3. Sources, Transport, and Storage of Sediment at Selected Sites in the Chesapeake Bay Watershed (United States)

    Gellis, Allen C.; Hupp, Cliff R.; Pavich, Milan J.; Landwehr, Jurate M.; Banks, William S.L.; Hubbard, Bernard E.; Langland, Michael J.; Ritchie, Jerry C.; Reuter, Joanna M.


    The Chesapeake Bay Watershed covers 165,800 square kilometers and is supplied with water and sediment from five major physiographic provinces: Appalachian Plateau, Blue Ridge, Coastal Plain, Piedmont, and the Valley and Ridge. Suspended-sediment loads measured in the Chesapeake Bay Watershed showed that the Piedmont Physiographic Province has the highest rates of modern (20th Century) sediment yields, measured at U.S. Geological Survey streamflow-gaging stations, and the lowest rates of background or geologic rates of erosion (~10,000 years) measured with in situ beryllium-10. In the agricultural and urbanizing Little Conestoga Creek Watershed, a Piedmont watershed, sources of sediment using the 'sediment-fingerprinting' approach showed that streambanks were the most important source (63 percent), followed by cropland (37 percent). Cesium-137 inventories, which quantify erosion rates over a 40-year period, showed average cropland erosion of 19.39 megagrams per hectare per year in the Little Conestoga Creek Watershed. If this erosion rate is extrapolated to the 13 percent of the watershed that is in cropland, then cropland could contribute almost four times the measured suspended-sediment load transported out of the watershed (27,600 megagrams per hectare per year), indicating that much of the eroded sediment is being deposited in channel and upland storage. The Piedmont has had centuries of land-use change, from forest to agriculture, to suburban and urban areas, and in some areas, back to forest. These land-use changes mobilized a large percentage of sediment that was deposited in upland and channel storage, and behind thousands of mill dams. The effects of these land-use changes on erosion and sediment transport are still being observed today as stored sediment in streambanks is a source of sediment. Cropland is also an important source of sediment. The Coastal Plain Physiographic Province has had the lowest sediment yields in the 20th Century and with sandy

  4. Bottom Boundary Layer Sediment Transport Processes in Fourleague Bay of Louisiana and Their Implication to Sediment Diversion and Coastal Restoration (United States)

    Wang, J.; Xu, K.; Bentley, S. J.; Restreppo, G. A.


    Building land with a rising sea is a challenging problem in many major deltaic systems around the world. The Atchafalaya deltaic area is one of only a few growing sites in Louisiana coast. The sediment delivered to this deltaic area is mainly from three reservoirs: (1) sediment derived from ongoing fluvial delivery; (2) mobile sediment delivered to the coastal basin during the past year by cold fronts, tropical cyclones, and others; (3) more consolidated sediment stored in the seabed or bay floor for more than 12 months. In order to better understand the far-field dispersal and deposition of fine sediments in the Atchafalaya system, two tripods were used to study the hydrodynamics and sediment dynamics at two stations in Fourleague Bay, which are 15 km southeast of Atchafalaya Delta. One tripod was located at the middle of the bay, and the other was near the marsh edge. Six sensors including OBS (Optical Backscatter Sensor) 3A, OBS 5+, ADV (Acoustic Doppler Velocimeter) Ocean, Argonaut ADV, and two wave gauges were planned to deploy in the early summer and winter of 2015 for a month, respectively. Our study was focused on the near-bed sediment transport from each of the above three reservoirs to wetlands under fair weather and event condition. Based on the seasonal surface suspended sediment concentration (SSC), salinity, as well as turbidity, wave and current data, we have investigated the bottom boundary layer sediment dynamics, in order to illustrate sediment deposition and erosion processes under fair weather and energetic conditions in the bay. During an energetic event in early summer 2015, strong southeasterly wind waves carried salty water from inner Louisiana shelf northwestward into the bay, and led to increasing wave height, bottom shear stress, salinity, and near-bed turbidity. After the event, there was apparent decreasing of these parameters. SSC data in the bay showed an increasing trend since April, which is probably related to the fine sediment

  5. Evaluating turbidity and suspended-sediment concentration relations from the North Fork Toutle River basin near Mount St. Helens, Washington; annual, seasonal, event, and particle size variations - a preliminary analysis. (United States)

    Uhrich, Mark A.; Spicer, Kurt R.; Mosbrucker, Adam; Christianson, Tami


    Regression of in-stream turbidity with concurrent sample-based suspended-sediment concentration (SSC) has become an accepted method for producing unit-value time series of inferred SSC (Rasmussen et al., 2009). Turbidity-SSC regression models are increasingly used to generate suspended-sediment records for Pacific Northwest rivers (e.g., Curran et al., 2014; Schenk and Bragg, 2014; Uhrich and Bragg, 2003). Recent work developing turbidity-SSC models for the North Fork Toutle River in Southwest Washington (Uhrich et al., 2014), as well as other studies (Landers and Sturm, 2013, Merten et al., 2014), suggests that models derived from annual or greater datasets may not adequately reflect shorter term changes in turbidity-SSC relations, warranting closer inspection of such relations. In-stream turbidity measurements and suspended-sediment samples have been collected from the North Fork Toutle River since 2010. The study site, U.S. Geological Survey (USGS) streamgage 14240525 near Kid Valley, Washington, is 13 river km downstream of the debris avalanche emplaced by the 1980 eruption of Mount St. Helens (Lipman and Mullineaux, 1981), and 2 river km downstream of the large sediment retention structure (SRS) built from 1987–1989 to mitigate the associated sediment hazard. The debris avalanche extends roughly 25 km down valley from the edifice of the volcano and is the primary source of suspended sediment moving past the streamgage (NF Toutle-SRS). Other significant sources are debris flow events and sand deposits upstream of the SRS, which are periodically remobilized and transported downstream. Also, finer material often is derived from the clay-rich original debris avalanche deposit, while coarser material can derive from areas such as fluvially reworked terraces.

  6. A preliminary assessment of the spatial sources of contemporary suspended sediment in the Ohio River basin, United States, using water quality data from the NASQAN programme in a source tracing procedure (United States)

    Zhang, Y.-S.; Collins, A.L.; Horowitz, A.J.


    Reliable information on catchment scale suspended sediment sources is required to inform the design of management strategies for helping abate the numerous environmental issues associated with enhanced sediment mobilization and off-site loadings. Since sediment fingerprinting techniques avoid many of the logistical constraints associated with using more traditional indirect measurement methods at catchment scale, such approaches have been increasingly reported in the international literature and typically use data sets collected specifically for sediment source apportionment purposes. There remains scope for investigating the potential for using geochemical data sets assembled by routine monitoring programmes to fingerprint sediment provenance. In the United States, routine water quality samples are collected as part of the US Geological Survey's revised National Stream Quality Accounting Network programme. Accordingly, the geochemistry data generated from these samples over a 10-year period (1996-2006) were used as the basis for a fingerprinting exercise to assess the key tributary sub-catchment spatial sources of contemporary suspended sediment transported by the Ohio River. Uncertainty associated with the spatial source estimates was quantified using a Monte Carlo approach in conjunction with mass balance modelling. Relative frequency weighted means were used as an alternative way of summarizing the spatial source contributions, thereby avoiding the need to use confidence limits. The results should be interpreted in the context of the routine, but infrequent nature, of the suspended sediment samples used to assemble geochemistry as a basis for the sourcing exercise. Nonetheless, the study demonstrates how routine monitoring samples can be used to provide some preliminary information on sediment provenance in large drainage basins. ?? 2011 John Wiley & Sons, Ltd.

  7. Streamflow and Suspended-Sediment Loads Before, During, and After H-3 Highway Construction, North Halawa, Haiku, South Fork Kapunahala, and Kamooalii Drainage Basins, Oahu, Hawaii, 1983-99 (United States)

    Wong, Michael F.; Yeatts, Daniel S.


    A long-term study (1983?99) was conducted to determine the effects of the H-3 Highway construction on streamflow and suspended-sediment transport on Oahu, Hawaii. Data were collected at five streamflow-gaging stations before, during, and after construction and at two stream-gaging stations during and after construction. Drainage areas at the seven streamflow-gaging stations ranged from 0.40 to 4.01 mi2 and highway construction affected from 4 to 15 percent of these areas. Analysis of covariance and regression techniques were used to assess changes in streamflow and suspended-sediment loads during and after construction, relative to before-construction conditions. Streamflow at the seven streamflow-gaging stations was compared to streamflow at an index station unaffected by highway construction. Streamflow data were divided into low- and high-flow classes, and the two flow classes were analyzed separately. Additionally, instantaneous peak flows were analyzed at three streamflow-gaging stations. During construction, observed low flows significantly increased by 108 percent at Luluku Stream, a tributary to Kamooalii Stream, and decreased by 31 percent at Kamooalii Stream. After construction, low flows increased by 47 percent at North Halawa Stream near Honolulu compared to low flows during construction. Low flows at Luluku Stream increased by 99 percent after construction compared to before construction. Increased low flows were attributed to removal of vegetation for construction and the increase of impervious areas that reduced infiltration. Decreased low flows were attributed to increased ground-water withdrawals and construction activities. High flows observed during highway construction compared to before construction increased significantly only at Haiku Stream (by 25 percent). Observed high flows after construction compared to during construction increased significantly only at Kamooalii Stream (by 34 percent). Observed high flows after construction compared to

  8. "Smart pebble" designs for sediment transport monitoring (United States)

    Valyrakis, Manousos; Alexakis, Athanasios; Pavlovskis, Edgars


    Sediment transport, due to primarily the action of water, wind and ice, is one of the most significant geomorphic processes responsible for shaping Earth's surface. It involves entrainment of sediment grains in rivers and estuaries due to the violently fluctuating hydrodynamic forces near the bed. Here an instrumented particle, namely a "smart pebble", is developed to investigate the exact flow conditions under which individual grains may be entrained from the surface of a gravel bed. This could lead in developing a better understanding of the processes involved, focusing on the response of the particle during a variety of flow entrainment events. The "smart pebble" is a particle instrumented with MEMS sensors appropriate for capturing the hydrodynamic forces a coarse particle might experience during its entrainment from the river bed. A 3-axial gyroscope and accelerometer registers data to a memory card via a microcontroller, embedded in a 3D-printed waterproof hollow spherical particle. The instrumented board is appropriately fit and centred into the shell of the pebble, so as to achieve a nearly uniform distribution of the mass which could otherwise bias its motion. The "smart pebble" is powered by an independent power to ensure autonomy and sufficiently long periods of operation appropriate for deployment in the field. Post-processing and analysis of the acquired data is currently performed offline, using scientific programming software. The performance of the instrumented particle is validated, conducting a series of calibration experiments under well-controlled laboratory conditions.

  9. Catchment soil moisture and rainfall characteristics as determinant factors for discharge/suspended sediment hysteretic loops in a small headwater catchment in the Spanish pyrenees

    NARCIS (Netherlands)

    Seeger, M.; Beguería, S.; Errea, M.P.; Arnáez, J.; Martí, C.; García-Ruiz, J.M.


    The concentration of suspended sediment and discharge generated during flood events are not normally homogenous, and the curve representing sediment concentration vs. discharge through time is often a hysteretic loop. Three types of hysteretic loops were found at Arnás, a Mediterranean headwater

  10. Sediment Transport Capacity and Channel Processes in a Humid Tropical Montane River - Rio Pacuare, Costa Rica (United States)

    Lind, P.; McDowell, P. F.


    Investigating sediment transport capacity as well as the spatial and temporal variations of sediment flux are critical component of river research, especially for applications in resource management and conservation, hazards assessment and planning, and riverine ecology. The bedload fraction of sediment transported through montane rivers often defines channel and bed form processes. It is understood that humid tropical montane rivers are capable of producing some of the largest quantities of sediment per unit drainage area. Bedload flux reported on a few Southeast Asian humid tropical montane rivers show that bedload constituted 16-75% of the total sediment load - this is notably higher than the generally accepted 10% of a channel's sediment load. However, to date almost all of the research done on sediment transport in humid tropical systems has focused on suspended load. This study presents annual bedload transport rate estimates for six field sites distributed within 45 river kilometers (Rkm) of the montane portion of the Rio Pacuare, located in the Talamanca Mountains of Costa Rica. This research reveals that flows capable of mobilizing the D84 occur on average at least once but often multiple times a year in this river system. The Rio Pacuare has a sufficient supply of sediment to meet its high transport capacity needs. As a result, large active bars composed of imbricated boulders define channel form at moderate and low flows throughout the study area. Differences in the magnitude, as well as the spatial and temporal variations of sediment flux at each field site are discussed in relation to stream power, and annual/inter-annual precipitation patterns. A unique mix of field and remote sensing techniques were applied to address these questions and to overcome some of the challenges of tropical river research. For example, due to the large grain size and high stream energy, grain mobilization and validation of modeled shear stress requirements for transport

  11. Suspended sediment fluxes in a tropical estuary, west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    AnilKumar, N.; DineshKumar, P.K.; Srinivas, K.

    of low river flow, the estuary received net sediment inputs from the continental shelf and during high flows exported sediments to the continental shelf depending on the magnitudes of the floods. The major input of sediment from the watershed was 8.8 x 10...

  12. A longshore sediment transport estimation for the Indian coast

    Digital Repository Service at National Institute of Oceanography (India)

    Nayak, B.U.; Chandramohan, P.

    An empirical sediment transport model has been developed based on longshore energy flux equation. Study indicates that annual gross sediment transport rate is high (1.5 x 10 super(6) m super(3) to 2.0 x 10 super(6) m super(3)) along the coasts...

  13. Sediment transport in an active erodible channel bend of ...

    Indian Academy of Sciences (India)

    Spatial variation of sediment transport in an alluvial sand-bed river bend needs to be understood with ... Local variation of sediment transport is primarily controlled by active bank erosion, land spur and sand bar ..... of Water, Environment, Energy and Society (WEES)-2009, New Delhi, India, 1670–1676. Karmaker T, Dutta S ...

  14. Wave Induced Mine Burial and Sediment Transport in Coastal Environment: Wave and Sediment Transport Modeling Studies (United States)


    predicting ripple and dune formation and evolution (e.g., Voropayev et al., 1999). In a larger context, this work will yield an experimentally...Engng. (in revision). Voropayev, S.I., McEachern, G.B., Boyer, D.L. and Fernando, H.J.S. (1999). “Dynamics of sand ripples and burial/scouring of...changes, in coastal and estuarine environments of active sediment transport (e.g., ripple migration). OBJECTIVE In the past year, our objective

  15. Sediment Transport Model for a Surface Irrigation System


    Mailapalli, Damodhara R.; Raghuwanshi, Narendra S.; Singh, Rajendra


    Controlling irrigation-induced soil erosion is one of the important issues of irrigation management and surface water impairment. Irrigation models are useful in managing the irrigation and the associated ill effects on agricultural environment. In this paper, a physically based surface irrigation model was developed to predict sediment transport in irrigated furrows by integrating an irrigation hydraulic model with a quasi-steady state sediment transport model to predict sediment load in fur...

  16. The algal lift: Buoyancy-mediated sediment transport (United States)

    Mendoza-Lera, Clara; Federlein, Laura L.; Knie, Matthias; Mutz, Michael


    The role of benthic algae as biostabilizers of sediments is well-known, however, their potential to lift and transport sediments remains unclear. Under low-flow conditions, matured algal mats may detach from the bed and may lift up sediment, thereby causing disturbance to the uppermost streambed sediment. We tested the potential of algal mats to lift sediments in 12 indoor flumes filled with sand (0.2 - 0.8 mm), gravel (2 - 8 mm) or a sand-gravel mixture (25/75% mass). After four weeks, the algal mats covered about 50% of the flumes area. Due to the accumulation of oxygen gas bubbles in the mats, that developed from high primary production at 4.5 weeks, about half of the algal mats detached from the bed carrying entangled sediments. Both the area covered by algal mats and detached area were similar among sediment types, but the amount of sediment transported tended to be higher for sand and sand-gravel mixture compared to gravel. Our results reveal that biologically mediated sediment transport mainly depends on the development of a dense filamentous algal matrix, that traps gas bubbles, increasing the mats buoyancy. This novel mechanism of sediment transport will occur in shallow ecosystems during low-flow periods, with the highest impact for sandy sediments.

  17. The roles of physical mixing and biochemical composition on the depositional characteristics of flocculated suspended sediment in the Eden estuary, Scotland (United States)

    Hope, Julie; Manning, Andrew; Aspden, Rebecca; Baas, Jaco; Paterson, David


    Sediment load in estuarine waters is generally composed of a mixture of sand, clay and biological matter and it is recognised that there is strong mediation of the physical behaviour of flocs by biological components of the system. Extracellular polymeric substances (EPS) secreted by benthic and pelagic bacteria and algae are a key variable influencing flocculation processes. Variation in the nature and concentration of polymers can alter sediment stability and transport in mixed sediment beds but these substances can also significantly enhance inter-particle cohesion in the water column and therefore deposition and transport. This study examined the variation in naturally occurring EPS concentration and its influence on several physical variables of flocs within the Eden Estuary, Scotland. Samples were collected for total suspended sediment and colormetric analysis of polymer concentration. Subsamples were transferred to the settling column of the LabSFLOC-2 - Laboratory Spectral Flocculation Characteristics -high resolution video floc camera system (Manning, 2006) where settling flocs were viewed (resolution~10μm) to determine floc size (D) and settling velocity (Ws) characteristics. Preliminary results indicate a wide range of microfloc (D160mm) fractions present, with the latter approaching 1 mm during flocculation conducive conditions. Correspondingly, when considering all floc samples, floc settling velocities generally spanned three orders of magnitude with floc size and settling velocities correlating with polymer concentrations. These typically ranged from slow settling (Ws of 0.01-0.05 mm.s-1) predominantly organically based microflocs to faster settling, significantly larger and more porous Macroflocs settling at ~10-15 mm.s-1. The temporal distributions of D and Ws, sediment and polymer concentrations, and the sugar composition of the polymers in suspension are examined in the paper with variation also related to physical and microbiological factors in

  18. Neutron activation analysis determination of trace elements in suspended particulate material and in central Thyrrenian sea sediments

    International Nuclear Information System (INIS)

    Madaro, M.; Moauro, R.; Boniforti, R.


    Neutron activation analysis and gamma-spectrometry have been applied to the instrumental determination of 26 elements (As, Au, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, Hg, La, Lu, Mn, Rb, Sb, Sc, Se, Sm, Ta, Tb, Th, W, Yb, Zn, Zr) in samples of suspended particulate matter and sediments collected in the stretch of Tyrrhenian Sea between the Volturno River mouth and the Cape of Circeo. Some of these elements have particular importance because they can be toxic to the organisms or can be used as tracers in the aquatic environment of radioisotopes generated in activation or fission processes. Results show that some elements, not constituting particular crystal lattices, are more concentrated in particulate matter than in sediments. Such results agree with the hypothesis, supported also by others, that particulate matter acts as a scavenger with respect to most microelements, because of both biological and physico-chemical phenomena

  19. Muddied waters: suspended sediment impacts on gill structure and aerobic scope in an endangered native and an invasive freshwater crayfish

    DEFF Research Database (Denmark)

    Rosewarne, P.J.; Svendsen, Jon Christian; Mortimer, R.J.G.


    Suspended sediment (SS) loadings in freshwater habitats have increased over the past century and SS is now a significant environmental stressor. Greater tolerance to environmental stressors has been proposed as a factor in the success of aquatic invasive species. Further, parasites may interact...... with environmental stressors to increase host susceptibility to loss of fitness and mortality. We compared the effects of SS exposure on the gill structure and aerobic scope of the endangered white-clawed crayfish (Austropotamobius pallipes), and the invasive signal crayfish (Pacifastacus leniusculus), and assessed...... impacts in relation to parasite burden. SS caused gill fouling and reduction in aerobic scope in both species, though A. pallipes was more susceptible than invasive P. leniusculus. The parasite Branchiobdella astaci, a crayfish worm that infests the gills, interacted with the sediment to affect gill...

  20. Sediment Transport and Slope Stability of Ship Shoal Borrow Areas for Coastal Restoration of Louisiana (United States)

    Liu, H.; Xu, K.; Bentley, S. J.; Li, C.; Miner, M. D.; Wilson, C.; Xue, Z.


    Sandy barrier islands along Louisiana coast are degrading rapidly due to both natural and anthropogenic factors. Ship Shoal is one of the largest offshore sand resources, and has been used as a borrow area for Caminada Headland Restoration Project. Our knowledge of sediment transport and infilling processes in this new sandy and dynamic borrow area is rather limited. High resolution sub-bottom seismic data, side scan sonar images, multi-beam bathymetry and laser sediment grain size data were used to study seafloor morphological evolution and pit wall stability in response to both physical and geological processes. The multi-beam bathymetry and seismic profiling inside the pit showed that disequilibrium conditions led to rapid infilling in the pits at the beginning, but this process slowed down after the pit slope became stable and topography became smooth. We hypothesize that the erosion of the adjacent seabed sediment by energetic waves and longshore currents, the supply of suspended sediment from the rivers, and the erodible materials produced by local mass wasting on pit walls are three main types of infilling sediments. Compared with mud-capped dredge pits, this sandy dredge pit seems to have more gentle slopes on pit walls, which might be controlled by the angle of repose. Infilling sediment seems to be dominantly sandy, with some mud patches on bathymetric depressions. This study helps us better understand the impacts of mining sediment for coastal restoration and improves sand resource management efforts.

  1. Hydrocarbons in the suspended matter and the bottom sediments in different regions of the Black Sea Russian sector

    Directory of Open Access Journals (Sweden)

    I. A. Nemirovskaya


    Full Text Available Content and composition of hydrocarbons (mainly the aliphatic ones in the suspended matter and the bottom sediments in the Gelendzhik Bay, the Big Sochi water area, the Feodosiya Bay and the Black Sea central part are defined and compared with the total organic carbon and chlorophyll a contents. It is shown that the aliphatic hydrocarbon concentrations exceeding the background ones are found only in the coastal zone. Advancing to the pelagic zone is accompanied by sharp decrease of their concentrations. Petroleum and pyrogenic hydrocarbons are mainly manifested in the polycyclic aromatic hydrocarbons composition. Influence of construction of the Olympic facilities upon distribution of hydrocarbons in the Big Sochi water area was of short duration, and already by 2015 the aliphatic hydrocarbons concentration decreased, on the average, up to 24 µg/l in the surface waters, and up to 18 µg/g – in the bottom sediments. Accumulation of hydrocarbons took place in bottom sediments, where their concentrations exceeded the background ones in terms of dry weight. In the Gelendzhik Bay, their content reached 252 μg/g, and in the composition of organic carbon (Corg > 1 %, which may indicate the contamination of sediments with oil products. In the Feodosiya Bay their part in the composition of Corg did not exceed 0.73 % and was 0.35 % on average. Natural alkanes dominated in the composition of aliphatic hydrocarbons. The bottom sediments are characterized by the predominance of odd high-molecular terrigenous alkanes. The content of polycyclic aromatic hydrocarbons in the studied sediments was rather low: up to 31 ng/g in the Gelendzhik Bay, up to 348 ng/g in the Feodosiya Bay. These concentrations according to the EPA classification are considered background, or minor petroleum hydrocarbons increase the level of aliphatic hydrocarbons in water and sediments, thus creating a modern hydrocarbon background.

  2. Evaluating sediment transport in flood-driven ephemeral tributaries using direct and acoustic methods. (United States)

    Stark, K.


    One common source of uncertainty in sediment transport modeling of large semi-arid rivers is sediment influx delivered by ephemeral, flood-driven tributaries. Large variations in sediment delivery are associated with these regimes due to the highly variable nature of flows within them. While there are many sediment transport equations, they are typically developed for perennial streams and can be inaccurate for ephemeral channels. Discrete, manual sampling is labor intensive and requires personnel to be on site during flooding. In addition, flooding within these tributaries typically last on the order of hours, making it difficult to be present during an event. To better understand these regimes, automated systems are needed to continuously sample bedload and suspended load. In preparation for the pending installation of an automated site on the Arroyo de los Piños in New Mexico, manual sediment and flow samples have been collected over the summer monsoon season of 2017, in spite of the logistical challenges. These data include suspended and bedload sediment samples at the basin outlet, and stage and precipitation data from throughout the basin. Data indicate a complex system; flow is generated primarily in areas of exposed bedrock in the center and higher elevations of the watershed. Bedload samples show a large coarse-grained fraction, with 50% >2 mm and 25% >6 mm, which is compatible with acoustic measuring techniques. These data will be used to inform future site operations, which will combine direct sediment measurement from Reid-type slot samplers and non-invasive acoustic measuring methods. Bedload will be indirectly monitored using pipe-style microphones, plate-style geophones, channel hydrophones, and seismometers. These instruments record vibrations and acoustic signals from bedload impacts and movement. Indirect methods for measuring of bedload have never been extensively evaluated in ephemeral channels in the southwest United States. Once calibrated

  3. Assessing Sediment and Nutrient Transport in the Pra Basin of Ghana

    African Journals Online (AJOL)

    Regression analysis was used to establish relationships between suspended sediment yield and nutrient export coefficient as the dependent variable, and runoff and catchment area as the independent variables. The established regression equation can be used to estimate suspended sediment or nutrient yield at any ...

  4. Transport and distribution of bottom sediments at Pirita Beach

    Directory of Open Access Journals (Sweden)

    Soomere, Tarmo


    Full Text Available The basic factors affecting sediment supply for and transport processes at Pirita Beach, a sandy section of the south­eastern coast of Tallinn Bay, are analysed. Observations of bathymetry, sediment properties and sources, sediment transport processes and their changes arising from coastal engineering activities are reported. The mean grain size is about 0.12 mm, with the fine sand fraction (0.063–0.125 mm accounting for about 77% of the sediments. Coarse sand dominates only along the waterline. The content of coarser sediments is greater in the northern part of the beach. A number of coastal engineering structures have blocked natural sediment supplies. The beach suffers from sediment deficit now and has lost about 400 m3 of sand annually from the dry beach between 1997 and 2005.

  5. Sediment Transport Model for a Surface Irrigation System

    Directory of Open Access Journals (Sweden)

    Damodhara R. Mailapalli


    Full Text Available Controlling irrigation-induced soil erosion is one of the important issues of irrigation management and surface water impairment. Irrigation models are useful in managing the irrigation and the associated ill effects on agricultural environment. In this paper, a physically based surface irrigation model was developed to predict sediment transport in irrigated furrows by integrating an irrigation hydraulic model with a quasi-steady state sediment transport model to predict sediment load in furrow irrigation. The irrigation hydraulic model simulates flow in a furrow irrigation system using the analytically solved zero-inertial overland flow equations and 1D-Green-Ampt, 2D-Fok, and Kostiakov-Lewis infiltration equations. Performance of the sediment transport model was evaluated for bare and cropped furrow fields. The results indicated that the sediment transport model can predict the initial sediment rate adequately, but the simulated sediment rate was less accurate for the later part of the irrigation event. Sensitivity analysis of the parameters of the sediment module showed that the soil erodibility coefficient was the most influential parameter for determining sediment load in furrow irrigation. The developed modeling tool can be used as a water management tool for mitigating sediment loss from the surface irrigated fields.

  6. Input-variable sensitivity assessment for sediment transport relations (United States)

    Fernández, Roberto; Garcia, Marcelo H.


    A methodology to assess input-variable sensitivity for sediment transport relations is presented. The Mean Value First Order Second Moment Method (MVFOSM) is applied to two bed load transport equations showing that it may be used to rank all input variables in terms of how their specific variance affects the overall variance of the sediment transport estimation. In sites where data are scarce or nonexistent, the results obtained may be used to (i) determine what variables would have the largest impact when estimating sediment loads in the absence of field observations and (ii) design field campaigns to specifically measure those variables for which a given transport equation is most sensitive; in sites where data are readily available, the results would allow quantifying the effect that the variance associated with each input variable has on the variance of the sediment transport estimates. An application of the method to two transport relations using data from a tropical mountain river in Costa Rica is implemented to exemplify the potential of the method in places where input data are limited. Results are compared against Monte Carlo simulations to assess the reliability of the method and validate its results. For both of the sediment transport relations used in the sensitivity analysis, accurate knowledge of sediment size was found to have more impact on sediment transport predictions than precise knowledge of other input variables such as channel slope and flow discharge.

  7. Influence of a circular jet arrangement in a rectangular tank on flow and suspended sediment release


    Althaus, Jenzer; Isabella, Jolanda Maria


    With the objective of high sediment release out of a rectangular tank the performance of a circular jet arrangement has been investigated. Therefore, experiments with four jets arranged in a horizontal circle placed in water with quasi homogeneous sediment concentration were conducted. The induced circulation was analysed by measuring the flow field. The influence of the flow circulation on suspension and on sediment release through the water intake was studied and discussed. The offbottom cl...

  8. In situ densimetric measurements as a surrogate for suspended-sediment concentrations in the Rio Puerco, New Mexico (United States)

    Brown, Jeb E.; Gray, John R.; Hornewer, Nancy J.


    Surrogate measurements of suspended-sediment concentration (SSC) are increasingly used to provide continuous, high-resolution, and demonstrably accurate data at a reasonable cost. Densimetric data, calculated from the difference between two in situ pressure measurements, exploit variations in real-time streamflow densities to infer SSCs. Unlike other suspendedsediment surrogate technologies based on bulk or digital optics, laser, or hydroacoustics, the accuracy of SSC data estimated using the pressure-difference (also referred to as densimetric) surrogate technology theoretically improves with increasing SCCs. Coupled with streamflow data, continuous suspended-sediment discharges can be calculated using SSC data estimated in real-time using the densimetric technology. The densimetric technology was evaluated at the Rio Puerco in New Mexico, a stream where SSC values regularly range from 10,000-200,000 milligrams per liter (mg/L) and have exceeded 500,000 mg/L. The constant-flow dual-orifice bubbler measures pressure using two precision pressure-transducer sensors at vertically aligned fixed locations in a water column. Water density is calculated from the temperature-compensated differential pressure and SSCs are inferred from the density data. A linear regression model comparing density values to field-measured SSC values yielded an R² of 0.74. Although the application of the densimetric surrogate is likely limited to fluvial systems with SSCs larger than about 10,000 mg/L, based on this and previous studies, the densimetric technology fills a void for monitoring streams with high SSCs.

  9. An exploratory study of using external fluid loading on a vibrating tube for measuring suspended sediment concentration in water

    International Nuclear Information System (INIS)

    Hsu, Y-S; Hwang, Y-F; Huang, J H


    This paper presents an exploratory study of using external fluid loading on a vibrating tube for measuring the suspended sediment concentration (SSC) in bodies of water such as rivers and reservoirs. This new measuring concept provides an opportunity for an automated on-site monitoring of the conditions in a body of water by taking the fluid sample instantaneously in the area surrounding the vibrating tube. The physical properties of the fluid sample are those of the fluid that naturally flows around the tube, and are more representative of those of the water with SSC to be measured. The theoretical analysis presented in this paper shows that the resonance frequencies of an immersed vibrating tube change significantly with mass density variations that normally occur in bodies of water with suspended sediment. These changes are sensitive enough to have a possible 1% resolution of the measured fluid density. The signal processing issues are discussed, and a schematic of a conceptual measuring setup is proposed. Based on the theoretical analyses and other measurement issues presented in the paper, using the loading by external fluid on a vibrating tube is feasible for measuring the SSC in water bodies

  10. Effects of suspended sediment on the development and hatching of herring (Clupea harengus) eggs

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Frantsen, Erik; Jensen, Carsten


    made to test the effect of the increased turbidity near marine mining, spoil disposal or dredging operations. Embryonic development was unaffected by suspended silt. Mortality rates varied significantly between aquaria, but the variation was unrelated to the experimental treatment with silt. Refs....

  11. Sediment transport patterns at Kuala Sungai Kemaman, Terengganu

    International Nuclear Information System (INIS)

    Abdul Kadir Ishak


    The objective of this study is to determine the transport rate and transport direction of the offshore sand of Kg Kuala Kema man and Kg Geliga coastline using both hydraulic data and radioactive tracers. the result would demonstrate if the offshore sand contributes to the sedimentation at the Kuala Kemaman LKIM jetty. It will also be used to assist coastal engineering Division, Jabatan Pengairan dan Saliran Malaysia in calibrating their mathematical model for sediment transport. (Author)

  12. Sediment transport processes in the Pearl River Estuary as revealed by grain-size end-member modeling and sediment trend analysis (United States)

    Li, Tao; Li, Tuan-Jie


    The analysis of grain-size distribution enables us to decipher sediment transport processes and understand the causal relations between dynamic processes and grain-size distributions. In the present study, grain sizes were measured from surface sediments collected in the Pearl River Estuary and its adjacent coastal areas. End-member modeling analysis attempts to unmix the grain sizes into geologically meaningful populations. Six grain-size end-members were identified. Their dominant modes are 0 Φ, 1.5 Φ, 2.75 Φ, 4.5 Φ, 7 Φ, and 8 Φ, corresponding to coarse sand, medium sand, fine sand, very coarse silt, silt, and clay, respectively. The spatial distributions of the six end-members are influenced by sediment transport and depositional processes. The two coarsest end-members (coarse sand and medium sand) may reflect relict sediments deposited during the last glacial period. The fine sand end-member would be difficult to transport under fair weather conditions, and likely indicates storm deposits. The three remaining fine-grained end-members (very coarse silt, silt, and clay) are recognized as suspended particles transported by saltwater intrusion via the flood tidal current, the Guangdong Coastal Current, and riverine outflow. The grain-size trend analysis shows distinct transport patterns for the three fine-grained end-members. The landward transport of the very coarse silt end-member occurs in the eastern part of the estuary, the seaward transport of the silt end-member occurs in the western part, and the east-west transport of the clay end-member occurs in the coastal areas. The results show that grain-size end-member modeling analysis in combination with sediment trend analysis help to better understand sediment transport patterns and the associated transport mechanisms.

  13. Sediment transport processes in the Pearl River Estuary as revealed by grain-size end-member modeling and sediment trend analysis (United States)

    Li, Tao; Li, Tuan-Jie


    The analysis of grain-size distribution enables us to decipher sediment transport processes and understand the causal relations between dynamic processes and grain-size distributions. In the present study, grain sizes were measured from surface sediments collected in the Pearl River Estuary and its adjacent coastal areas. End-member modeling analysis attempts to unmix the grain sizes into geologically meaningful populations. Six grain-size end-members were identified. Their dominant modes are 0 Φ, 1.5 Φ, 2.75 Φ, 4.5 Φ, 7 Φ, and 8 Φ, corresponding to coarse sand, medium sand, fine sand, very coarse silt, silt, and clay, respectively. The spatial distributions of the six end-members are influenced by sediment transport and depositional processes. The two coarsest end-members (coarse sand and medium sand) may reflect relict sediments deposited during the last glacial period. The fine sand end-member would be difficult to transport under fair weather conditions, and likely indicates storm deposits. The three remaining fine-grained end-members (very coarse silt, silt, and clay) are recognized as suspended particles transported by saltwater intrusion via the flood tidal current, the Guangdong Coastal Current, and riverine outflow. The grain-size trend analysis shows distinct transport patterns for the three fine-grained end-members. The landward transport of the very coarse silt end-member occurs in the eastern part of the estuary, the seaward transport of the silt end-member occurs in the western part, and the east-west transport of the clay end-member occurs in the coastal areas. The results show that grain-size end-member modeling analysis in combination with sediment trend analysis help to better understand sediment transport patterns and the associated transport mechanisms.

  14. Measuring and Modeling Suspended Sediment and Nutrient Yields from a Mixed-Land-Use Watershed of the Central U.S. (United States)

    Zeiger, S. J.; Hubbart, J. A.


    A nested-scale watershed study design was used to monitor water quantity and quality of an impaired 3rd order stream in a rapidly urbanizing mixed-land-use watershed of the central USA. Grab samples were collected at each gauging site (n=836 samples x 5 gauging sites) and analyzed for suspended sediment, total phosphorus, and inorganic nitrogen species during the four year study period (2010 - 2013). Observed data were used to quantify relationships between climate, land use and pollutant loading. Additionally, Soil and Water Assessment Tool (SWAT) estimates of monthly stream flow, suspended sediment, total phosphorus, nitrate, nitrite, and ammonium were validated. Total annual precipitation ranged from approximately 650 mm during 2012 (extreme drought year) to 1350 mm during 2010 (record setting wet year) which caused significant (ppollutant yields (i.e. loads per unit area) that ranged from 115 to 174%. Multiple linear regression analyses showed significant (ppollutant loading, annual total precipitation (positive correlate), urban land use (positive correlate), forested land use (negative correlate), and wetland land use (negative correlate). Results from SWAT model performance assessment indicated calibration was necessary to achieve Nash-Sutcliff Efficiency (NSE) values greater than 0.05 for monthly pollutant loads. Calibrating the SWAT model to multiple gauging sites within the watershed improved estimates of monthly stream flow (NSE=0.83), and pollutant loads (NSE>0.78). However, nitrite and ammonium loads were underestimated by more than four orders of magnitude (NSEpollutant transport, and the benefits of calibrating the SWAT model to multiple gauging sites in mixed-land-use watersheds.

  15. Quantifying Suspended Sediment of a Missouri Ozark Border Stream Using Laser In-Situ Scattering and Transmissometry (United States)

    Freeman, G. W.; Hubbart, J. A.


    Sediment is the leading cause of water quality impairment globally. Midwestern U.S. streams are among the leading fresh water systems exhibiting highest sediment concentrations. Land managers in the Midwest are concerned about high concentrations of sediment that may threaten water quality and thus the availability of potable water, aquatic habitat, recreation, and many other natural resource commodities. There is a general lack of understanding of the relationships between land-use, sediment concentration and water quality in the Central U.S. Studies are therefore warranted that supply information leading to a) improved understanding of suspended sediment concentrations, b) the relationship between sediment concentration and land use/land cover, c) the relationship between observed sediment loading and Midwest hydroclimatology, and d) comprehensive data sets that will result in improved management of fresh water and natural resources. To address these issues, a study was initiated in the fall of 2008 in the Hinkson Creek Watershed (HCW) located in Central Missouri using innovative technology to quantify sediment concentrations and stream sediment loading. Sediment loading into Hinkson Creek was identified previously as a probable source of impairment of beneficial uses from sources including; point, non-point, and in-stream erosion. Increased development and poor erosion control practices have been shown to increase sediment delivery and flux. Hinkson Creek flows northwesterly through Boone County in central Missouri spanning a 22,791ha watershed. The HCW has a mix of agriculture (39%), grassland (1%), forested (35%), wetland/open water (2%), and urban (23%) land uses/land covers. Thus, five hydro-climate and water quality stations were strategically positioned along Hinkson Creek in a nested-scale watershed study design to capture differing land use and cover classes. Laser In-Situ Scattering and Transsmisometry (LISST) units were installed to collect total and

  16. Characterization and quantification of suspended sediment sources to the Manawatu River, New Zealand. (United States)

    Vale, S S; Fuller, I C; Procter, J N; Basher, L R; Smith, I E


    Knowledge of sediment movement throughout a catchment environment is essential due to its influence on the character and form of our landscape relating to agricultural productivity and ecological health. Sediment fingerprinting is a well-used tool for evaluating sediment sources within a fluvial catchment but still faces areas of uncertainty for applications to large catchments that have a complex arrangement of sources. Sediment fingerprinting was applied to the Manawatu River Catchment to differentiate 8 geological and geomorphological sources. The source categories were Mudstone, Hill Subsurface, Hill Surface, Channel Bank, Mountain Range, Gravel Terrace, Loess and Limestone. Geochemical analysis was conducted using XRF and LA-ICP-MS. Geochemical concentrations were analysed using Discriminant Function Analysis and sediment un-mixing models. Two mixing models were used in conjunction with GRG non-linear and Evolutionary optimization methods for comparison. Discriminant Function Analysis required 16 variables to correctly classify 92.6% of sediment sources. Geological explanations were achieved for some of the variables selected, although there is a need for mineralogical information to confirm causes for the geochemical signatures. Consistent source estimates were achieved between models with optimization techniques providing globally optimal solutions for sediment quantification. Sediment sources was attributed primarily to Mudstone, ≈38-46%; followed by the Mountain Range, ≈15-18%; Hill Surface, ≈12-16%; Hill Subsurface, ≈9-11%; Loess, ≈9-15%; Gravel Terrace, ≈0-4%; Channel Bank, ≈0-5%; and Limestone, ≈0%. Sediment source apportionment fits with the conceptual understanding of the catchment which has recognized soft sedimentary mudstone to be highly susceptible to erosion. Inference of the processes responsible for sediment generation can be made for processes where there is a clear relationship with the geomorphology, but is problematic for

  17. Evaluation of the method of collecting suspended sediment from large rivers by discharge-weighted pumping and separation by continuous- flow centrifugation (United States)

    Moody, J.A.; Meade, R.H.


    The efficacy of the method is evaluated by comparing the particle size distributions of sediment collected by the discharge-weighted pumping method with the particle size distributions of sediment collected by depth integration and separated by gravitational settling. The pumping method was found to undersample the suspended sand sized particles (>63 ??m) but to collect a representative sample of the suspended silt and clay sized particles (<63??m). The success of the discharge-weighted pumping method depends on how homogeneously the silt and clay sized particles (<63 ??m) are distributed in the vertical direction in the river. The degree of homogeneity depends on the composition and degree of aggregation of the suspended sediment particles. -from Authors

  18. Lateral baroclinic forcing enhances sediment transport from shallows to channel in an estuary (United States)

    Lacy, Jessica R.; Gladding, Steve; Brand, Andreas; Collignon, Audric; Stacey, Mark


    We investigate the dynamics governing exchange of sediment between estuarine shallows and the channel based on field measurements at eight stations spanning the interface between the channel and the extensive eastern shoals of South San Francisco Bay. The study site is characterized by longitudinally homogeneous bathymetry and a straight channel, with friction more important than the Coriolis forcing. Data were collected for 3 weeks in the winter and 4 weeks in the late summer of 2009, to capture a range of hydrologic and meteorologic conditions. The greatest sediment transport from shallows to channel occurred during a pair of strong, late-summer wind events, with westerly winds exceeding 10 m/s for more than 24 h. A combination of wind-driven barotropic return flow and lateral baroclinic circulation caused the transport. The lateral density gradient was produced by differences in temperature and suspended sediment concentration (SSC). During the wind events, SSC-induced vertical density stratification limited turbulent mixing at slack tides in the shallows, increasing the potential for two-layer exchange. The temperature- and SSC-induced lateral density gradient was comparable in strength to salinity-induced gradients in South Bay produced by seasonal freshwater inflows, but shorter in duration. In the absence of a lateral density gradient, suspended sediment flux at the channel slope was directed towards the shallows, both in winter and during summer sea breeze conditions, indicating the importance of baroclinically driven exchange to supply of sediment from the shallows to the channel in South San Francisco Bay and systems with similar bathymetry.

  19. Size graded sediment dynamics: from the processes characterization to the transport modelling in the English Channel

    International Nuclear Information System (INIS)

    Blanpain, O.


    The purpose of this work is the implementation of a sediment transport model in the English Channel. The design of such a model requires the identification of the physical processes, their modelling and their in-situ validation. Because of the sedimentary particularities of the study area, modelling of the mechanical behaviour of a non uniform mixture of sediments and particularly of the fine grains within a coarse matrix is required. This study focused on the characterization of the relevant processes by acquisition of experimental and in-situ data. Data acquired in hydro-sedimentary conditions comparable to those found in the English Channel are scarce. A new instrument and image processing technique were specifically conceived and implemented in-situ to observe and measure, with a high temporal resolution, the dynamics of a strongly heterogeneous mixture of particles in a grain-size scale. The data collected compared well with several existing formulations. One of these formulations was chosen to be adapted. The transfer dynamics of fine grains in coarse sediments and their depth of penetration were acquired from stratigraphic samples. The sediment transport model deals with multi-size grains and multi sedimentary layers, it is forced by swell and currents, and accounts for bead load and suspended load transports. It was applied to realistic scenarios for the English Channel. (author)

  20. Relations between continuous real-time turbidity data and discrete suspended-sediment concentration samples in the Neosho and Cottonwood Rivers, east-central Kansas, 2009-2012 (United States)

    Foster, Guy M.


    The Neosho River and its primary tributary, the Cottonwood River, are the primary sources of inflow to the John Redmond Reservoir in east-central Kansas. Sedimentation rate in the John Redmond Reservoir was estimated as 743 acre-feet per year for 1964–2006. This estimated sedimentation rate is more than 80 percent larger than the projected design sedimentation rate of 404 acre-feet per year, and resulted in a loss of 40 percent of the conservation pool since its construction in 1964. To reduce sediment input into the reservoir, the Kansas Water Office implemented stream bank stabilization techniques along an 8.3 mile reach of the Neosho River during 2010 through 2011. The U.S. Geological Survey, in cooperation with the Kansas Water Office and funded in part through the Kansas State Water Plan Fund, operated continuous real-time water-quality monitors upstream and downstream from stream bank stabilization efforts before, during, and after construction. Continuously measured water-quality properties include streamflow, specific conductance, water temperature, and turbidity. Discrete sediment samples were collected from June 2009 through September 2012 and analyzed for suspended-sediment concentration (SSC), percentage of sediments less than 63 micrometers (sand-fine break), and loss of material on ignition (analogous to amount of organic matter). Regression models were developed to establish relations between discretely measured SSC samples, and turbidity or streamflow to estimate continuously SSC. Continuous water-quality monitors represented between 96 and 99 percent of the cross-sectional variability for turbidity, and had slopes between 0.91 and 0.98. Because consistent bias was not observed, values from continuous water-quality monitors were considered representative of stream conditions. On average, turbidity-based SSC models explained 96 percent of the variance in SSC. Streamflow-based regressions explained 53 to 60 percent of the variance. Mean squared

  1. Contemporary sediment-transport processes in submarine canyons. (United States)

    Puig, Pere; Palanques, Albert; Martín, Jacobo


    Submarine canyons are morphological incisions into continental margins that act as major conduits of sediment from shallow- to deep-sea regions. However, the exact mechanisms involved in sediment transfer within submarine canyons are still a subject of investigation. Several studies have provided direct information about contemporary sedimentary processes in submarine canyons that suggests different modes of transport and various triggering mechanisms. Storm-induced turbidity currents and enhanced off-shelf advection, hyperpycnal flows and failures of recently deposited fluvial sediments, dense shelf-water cascading, canyon-flank failures, and trawling-induced resuspension largely dominate present-day sediment transfer through canyons. Additionally, internal waves periodically resuspend ephemeral deposits within canyons and contribute to dispersing particles or retaining and accumulating them in specific regions. These transport processes commonly deposit sediments in the upper- and middle-canyon reaches for decades or centuries before being completely or partially flushed farther down-canyon by large sediment failures.

  2. On extracting sediment transport information from measurements of luminescence in river sediment (United States)

    Gray, Harrison J.; Tucker, Gregory E.; Mahan, Shannon; McGuire, Chris; Rhodes, Edward J.


    Accurately quantifying sediment transport rates in rivers remains an important goal for geomorphologists, hydraulic engineers, and environmental scientists. However, current techniques for measuring long-time scale (102–106 years) transport rates are laborious, and formulae to predict transport are notoriously inaccurate. Here we attempt to estimate sediment transport rates by using luminescence, a property of common sedimentary minerals that is used by the geoscience community for geochronology. This method is advantageous because of the ease of measurement on ubiquitous quartz and feldspar sand. We develop a model from first principles by using conservation of energy and sediment mass to explain the downstream pattern of luminescence in river channel sediment. We show that the model can accurately reproduce the luminescence observed in previously published field measurements from two rivers with very different sediment transport styles. The model demonstrates that the downstream pattern of river sand luminescence should show exponential-like decay in the headwaters which asymptotes to a constant value with further downstream distance. The parameters from the model can then be used to estimate the time-averaged virtual velocity, characteristic transport lengthscale, storage time scale, and floodplain exchange rate of fine sand-sized sediment in a fluvial system. The sediment transport values predicted from the luminescence method show a broader range than those reported in the literature, but the results are nonetheless encouraging and suggest that luminescence demonstrates potential as a sediment transport indicator. However, caution is warranted when applying the model as the complex nature of sediment transport can sometimes invalidate underlying simplifications.

  3. Impact of bacterial NO3- transport on sediment biogeochemistry

    DEFF Research Database (Denmark)

    Sayama, Mikio; Risgaard-Petersen, Nils; Nielsen, Lars Peter


    Experiments demonstrated that Beggiatoa could induce a H2S-depleted suboxic zone of more than 10 mm in marine sediments and cause a divergence in sediment NO3– reduction from denitrification to dissimilatory NO3– reduction to ammonium. pH, O2, and H2S profiles indicated that the bacteria oxidized......2S with NO3– and transported S0 to the sediment surface for aerobic oxidation....

  4. Impact of Bacterial NO3- Transport on Sediment Biogeochemistry

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter


    Experiments demonstrated that Beggiatoa could induce a H2S-depleted suboxic zone of more than 10 mm in marine sediments and cause a divergence in sediment NO3- reduction from denitrification to dissimilatory NO3- reduction to ammonium. pH, O2, and H2S profiles indicated that the bacteria oxidized......2S with NO3- and transported S0 to the sediment surface for aerobic oxidation....

  5. Circulation and suspended particulate matter transport in a tidally dominated estuary: caravelas estuary, Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Carlos Augusto França Schettini


    Full Text Available The circulation and transport of suspended particulate matter in the Caravelas Estuary are assessed. Nearly-synoptic hourly hydrographic, current (ADCP velocity and volume transport and suspended particulate matter data were collected during a full semidiurnal spring tide, on the two transects Boca do Tomba and Barra Velha and on longitudinal sections at low and high tide. On the first transect the peak ebb currents (-1.5 ms-1 were almost twice as strong as those of the wider and shallow Barra Velha inlet (-0.80 ms-1 and the peak flood currents were 0.75 and 0.60 ms-1, respectively. Due to the strong tidal currents both inlets had weak vertical salinity stratification and were classified with the Stratification-circulation Diagram as Type 2a (partially mixed-weakly stratified and Type 1a (well mixed. Volume transports were very close, ranging from -3,500 to 3,100 m³s-1 at the ebb and flood, respectively, with a residual -630 m³s-1. The concentration of the suspended particulate matter was closely related to the tidal variation and decreased landwards from 50 mg.L-1 at the estuary mouth, to 10 mg.L-1 at distances of 9 and 16 km for the low and high tide experiments, respectively. The total residual SPM transport was out of the estuary at rates of -18 tons per tidal cycle.A circulação e o transporte de material particulado em suspensão no Estuário de Caravelas são pesquisados. Dados quase-sinóticos hidrográficos, de correntes (velocidade e transporte de volume com ADCP e de material particulado em suspensão, foram medidos em intervalos horários durante um ciclo semidiurno de maré de sizígia, em duas seções transversais na Boca do Tomba e na Barra Velha e também em seções longitudinais na baixa-mar e na preamar. Na primeira transversal as correntes máximas de vazante (-1,50 m s-1 foram quase duas vezes mais intensas do que na seção transversal mais larga e rasa Barra Velha, (-0,80 m s-1 e as maiores velocidades das correntes de

  6. Source identification of fine-grained suspended sediment in the Kharaa River basin, northern Mongolia

    Energy Technology Data Exchange (ETDEWEB)

    Theuring, Philipp [Department of Aquatic Ecosystem Analysis and Management — ASAM, Helmholtz Centre for Environmental Research — UFZ, Brückstrasse 3a, D-39114 Magdeburg (Germany); Collins, Adrian L. [Sustainable Soils and Grassland Systems Department, Rothamsted Research, North Wyke, Okehampton, Devon EX20 2SB (United Kingdom); Rode, Michael [Department of Aquatic Ecosystem Analysis and Management — ASAM, Helmholtz Centre for Environmental Research — UFZ, Brückstrasse 3a, D-39114 Magdeburg (Germany)


    Fine sediment inputs into river systems can be a major source of nutrients and heavy metals and have a strong impact on water quality and ecosystem functions of rivers and lakes, including those in semiarid regions. However, little is known to date about the spatial distribution of sediment sources in most large scale river basins in Central Asia. Accordingly, a sediment source fingerprinting technique was used to assess the spatial sources of fine-grained (< 10 μm) sediment in the 15 000 km{sup 2} Kharaa River basin in northern Mongolia. Variation in geochemical composition (e.g. in Ti, Sn, Mo, Mn, As, Sr, B, U, Ca and Sb) was used for sediment source discrimination with geochemical composite fingerprints based on Genetic Algorithm (GA)-driven Discriminant Function Analysis, the Kruskal–Wallis H-test and Principal Component Analysis. All composite fingerprints yielded a satisfactory GOF (> 0.97) and were subsequently used for numerical mass balance modelling with uncertainty analysis. The contributions of the individual sub-catchment spatial sediment sources varied from 6.4% (the headwater sub-catchment of Sugnugur Gol) to 36.2% (the Kharaa II sub-catchment in the middle reaches of the study basin), generally showing higher contributions from the sub-catchments in the middle, rather than the upstream, portions of the study area. The importance of river bank erosion is shown to increase from upstream to midstream tributaries. The source tracing procedure provides results in reasonable accordance with previous findings in the study region and demonstrates the applicability and associated uncertainties of the approach for fine-grained sediment source investigation in large scale semi-arid catchments. - Highlights: • Applied statistical approach for selecting composite fingerprints in Mongolia. • Geochemical fingerprinting for the definition of source areas in semiarid catchment. • Test of applicability of sediment sourcing in large scale semi-arid catchments

  7. Source identification of fine-grained suspended sediment in the Kharaa River basin, northern Mongolia

    International Nuclear Information System (INIS)

    Theuring, Philipp; Collins, Adrian L.; Rode, Michael


    Fine sediment inputs into river systems can be a major source of nutrients and heavy metals and have a strong impact on water quality and ecosystem functions of rivers and lakes, including those in semiarid regions. However, little is known to date about the spatial distribution of sediment sources in most large scale river basins in Central Asia. Accordingly, a sediment source fingerprinting technique was used to assess the spatial sources of fine-grained (< 10 μm) sediment in the 15 000 km 2 Kharaa River basin in northern Mongolia. Variation in geochemical composition (e.g. in Ti, Sn, Mo, Mn, As, Sr, B, U, Ca and Sb) was used for sediment source discrimination with geochemical composite fingerprints based on Genetic Algorithm (GA)-driven Discriminant Function Analysis, the Kruskal–Wallis H-test and Principal Component Analysis. All composite fingerprints yielded a satisfactory GOF (> 0.97) and were subsequently used for numerical mass balance modelling with uncertainty analysis. The contributions of the individual sub-catchment spatial sediment sources varied from 6.4% (the headwater sub-catchment of Sugnugur Gol) to 36.2% (the Kharaa II sub-catchment in the middle reaches of the study basin), generally showing higher contributions from the sub-catchments in the middle, rather than the upstream, portions of the study area. The importance of river bank erosion is shown to increase from upstream to midstream tributaries. The source tracing procedure provides results in reasonable accordance with previous findings in the study region and demonstrates the applicability and associated uncertainties of the approach for fine-grained sediment source investigation in large scale semi-arid catchments. - Highlights: • Applied statistical approach for selecting composite fingerprints in Mongolia. • Geochemical fingerprinting for the definition of source areas in semiarid catchment. • Test of applicability of sediment sourcing in large scale semi-arid catchments.

  8. Tidal influence on suspended sediment distribution and dispersal in the northern Andaman Sea and Gulf of Martaban

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Rao, P.S.; Rao, K.H.; Thwin, S.; Rao, N.S.; Raiker, V.

    mg l sub(-1)) increases from less than 15000 km sup(2) during neap tide to more than 45000 km2 during spring tide. The sediment discharged by the Ayeyarwady River is transported mainly eastward, along the coast, into the Gulf of Martaban. Occasionally...

  9. Sediment transport in the area of the Sopot pier (United States)

    Przyborska, Anna; Jakacki, Jaromir; Andrzejewski, Jan


    Coastal sediment transport is a natural process that appears when energy of waves is sufficient for moving solid particles from the bottom. Sediment transport rate depends on the median diameter of local sand and it is compatible with the direction of wave propagation. Also it is natural, that any protruded from the beach construction disturbs continuity of beach transport caused by waves. The Sopot pier has been built over 100 years ago and it is the longest wooden pier on the Baltic Sea coast, it is about half kilometre long. The pier is located at the end of the Monte Casino street and it is one of the biggest attractions of the city as well as in the country. In the past and now we have observed the disturbed sediment transport in the area of the Sopot pier. But during recent years, this process has gained greater momentum. The beach at the Sopot pier has been growing by several meters. All indicates that the cause of the observed phenomenon is the marina. The marina structure which is in some distance from the shore, has been acting as a powerful, emerged breakwater boundary. As a tool the sediment transport model was implemented for Sopot pier area. The implemented numerical forecasting sediment transport model in the area of the Sopot pier reflects well the deposit growth rate for the archived data from 2010 to 2015. On the basis of differences in bathymetry data provided by the Maritime office and the analysis the model results the average deposits in accumulation in the pear area was determined to be about 16,000 m3 / year for the assumed area of analysis, the model have shown similar result. The analysis suggests that strong winds generating significant waves as well as meaningful sediment transport dominate in the autumn and winter. You cannot, however, rule out strong waves in summer. Under moderate waves the sediment transport is insignificant. The most intense movement of the sediment is observed in the vicinity of the shoreline, it disappears with

  10. Resuspension and transport of suspended solids in Eurajoensalmi Bay. Final report of monitoring activities in 2009-2011

    International Nuclear Information System (INIS)

    Mykkanen, J.; Kiirikki, M.; Lindfors, A.


    The goal of monitoring activities carried out in Eurajoensalmi Bay was to indentify factors affecting dispersal of river waters and suspended solid matter in the estuary area. In addition to suspended solids load and dispersal of river water, also release of sedimented particles from the sea bed in resuspension was studied. River water quality and discharge as well as resuspension in Eurajoensalmi estuary area were monitored with Luode automatic monitoring stations equipped with water quality, water level, wave height and weather sensors. Dynamics of Eurajoensalmi estuary area was studied by installing profiling current meters (ADCP) and water quality sensors to the sea floor at the mouth of Eurajoensalmi. Spatial variation of surface water quality was monitored with a flow-through method from a moving vessel and manual profiling several times during the monitoring period. Collected data was processed and used in determining suspended solids balance of Eurajoensalmi Bay. The balance was determined by creating a regression model for water exchange and sediment flux over the cross section at the mouth of Eurajoensalmi. Regression model was created also to determine resuspension in Eurajoensalmi area. Sediment flux and resuspension were modeled using long term wind data from Kylmaepihlaja meteorological station as a variable to determine overall sediment balance of Eurajoensalmi

  11. Sediment texture, distribution and transport on the Ayeyarwady continental shelf, Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.S.; Ramaswamy, V.; Thwin, S.

    (Ramaswamy et al., 2004) we reported suspended sediment concen- trations in the northern Andaman sea and oscillation of the turbid front by about 150 km, in phase with spring-neap tidal cycle in the Gulf of Martaban. In this paper, we investigate textural... induced coastal currents aided by the prevailing westerly currents generated by the SW monsoon. Tidal currents further push the sediments into the waters of the Gulf of Martaban, where most of the suspended sediment is deposited (Fig. 4). Negligible...

  12. Research Note:Effects of human activities on the Yangtze River suspended sediment flux into the estuary in the last century

    Directory of Open Access Journals (Sweden)

    S. L. Yang


    Full Text Available The surface erosion area in the Yangtze River basin increased from 364×103 km2 in the 1950s to 707×103 km2 in 2001 due to a great increase in population. Based on the regression relationship between surface erosion area and population, the surface erosion area was predicted to be about 280×103 km2 at the beginning of the 20th century. The sediment yield, which increased by about 30% during the first six decades of the 20th century, was closely related to the surface erosion area in this river basin. The Yangtze annual suspended sediment flux into the estuary was about 395×106 t a-1 at the beginning of the century, and this gradually increased to an average of 509×106 t a-1 in the 1960s. The increase in the suspended sediment flux into the estuary was accelerated in the 1950s and the 1960s due to the rapid increase in population and land use immediately after the Second World War and the Liberation War. After the riverine suspended sediment flux reached its maximum in the 1960s, it decreased to 6 t a-1 in 2003. Construction of dams was found to be the principal cause for this decreasing trend because, during the same period, (a the riverine water discharge did not show a decreasing trend, (b water diversion was not influential and (c sedimentation in lakes and canals of the middle and lower reaches did not increase. The total storage capacity of reservoirs has increased dramatically over the past half century. The amount of sediment trapped in reservoirs has increased to more than half a billion t a-1. As a result, the suspended sediment flux into the estuary dramatically decreased, even though the sediment yield from many areas of the basin increased in recent decades. Human activities gradually increased the suspended sediment flux into the estuary before the 1960s and then rapidly decreased it. The last century was a period when the Yangtze suspended sediment flux into the estuary was dramatically affected by human activities. Keywords

  13. Particle Size Distribution Controls the Threshold Between Net Sediment Erosion and Deposition in Suspended Load Dominated Flows (United States)

    Dorrell, R. M.; Amy, L. A.; Peakall, J.; McCaffrey, W. D.


    The central problem of describing most environmental and industrial flows is predicting when material is entrained into, or deposited from, suspension. The threshold between erosional and depositional flow has previously been modeled in terms of the volumetric amount of material transported in suspension. Here a new model of the threshold is proposed, which incorporates (i) volumetric and particle size limits on a flow's ability to transport material in suspension, (ii) particle size distribution effects, and (iii) a new particle entrainment function, where erosion is defined in terms of the power used to lift mass from the bed. While current suspended load transport models commonly use a single characteristic particle size, the model developed herein demonstrates that particle size distribution is a critical control on the threshold between erosional and depositional flow. The new model offers an order of magnitude, or better, improvement in predicting the erosional-depositional threshold and significantly outperforms existing particle-laden flow models.

  14. Hydrodynamic Drivers of Sediment Transport Across a Fringing Reef

    NARCIS (Netherlands)

    Bodde, W.P.; Pomeroy, A.W.M.; Van Dongeren, A.R.; Lowe, R.; van Thiel de Vries, J.S.M.


    Coral reefs are highly valuable ecosystems, which are under an increasing number of environmental pressures. Sedimentation and sediment transport patterns are among key physical drivers of coral reefs, so it is important to improve our understanding of these poorly studied dynamics on reefs. To this

  15. Neural network-genetic programming for sediment transport

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, A.K.; Deo, M.C.; SanilKumar, V.

    The planning, operation, design and maintenance of almost all harbour and coastal engineering facilities call for an estimation of the longshore sediment transport rate. This is currently and popularly done with the help of empirical equations...

  16. Complexities in coastal sediment transport studies by numerical modelling

    Digital Repository Service at National Institute of Oceanography (India)

    Ilangovan, D.; ManiMurali, R.

    authors have tried to convey the complexities involved in accurate prediction of coastal sediment transport studies by numerical methods due to some unpredictable variations in the input parameters pertaining to the challenging coastal environments...

  17. Pesticide concentrations in water and in suspended and bottom sediments in the New and Alamo rivers, Salton Sea Watershed, California, April 2003 (United States)

    LeBlanc, Lawrence A.; Orlando, James L.; Kuivila, Kathryn


    This report contains pesticide concentration data for water, and suspended and bed sediment samples collected in April 2003 from twelve sites along the New and Alamo Rivers in the Salton Sea watershed, in southeastern California. The study was done in collaboration with the California State Regional Water Quality Control Board, Colorado River Region, to assess inputs of current-use pesticides associated with water and sediment into the New and Alamo Rivers. Five sites along the New River and seven sites along the Alamo River, downstream of major agricultural drains, were selected and covered the lengths of the rivers from the international boundary to approximately 1.5 km from the river mouths. Sampling from bridges occurred at seven of the twelve sites. At these sites, streamflow measurements were taken. These same sites were also characterized for cross-stream homogeneity by measuring dissolved oxygen, pH, specific conductance, temperature, and suspended solids concentration at several vertical (depths) and horizontal (cross-stream) points across the river. Large volume water samples (200?300 L) were collected for isolation of suspended sediments by flow-through centrifugation. Water from the outflow of the flow-through centrifuge was sampled for the determination of aqueous pesticide concentrations. In addition, bottom sediments were sampled at each site. Current-use pesticides and legacy organochlorine compounds (p,p'-DDT, p,p'-DDE and p,p'-DDD) were extracted from sediments and measured via gas chromatography/mass spectrometry (GC/MS). Organic carbon and percentage of fines were also determined for suspended and bottom sediments. Cross-stream transects of dissolved constituents and suspended sediments showed that the rivers were fairly homogeneous at the sites sampled. Streamflow was higher at the outlet sites, with the Alamo River having higher flow (1,240 cfs) than the New River (798 cfs). Twelve current-use pesticides, one legacy organochlorine compound (p

  18. Dynamic linear models to explore time-varying suspended sediment-discharge rating curves (United States)

    Ahn, Kuk-Hyun; Yellen, Brian; Steinschneider, Scott


    This study presents a new method to examine long-term dynamics in sediment yield using time-varying sediment-discharge rating curves. Dynamic linear models (DLMs) are introduced as a time series filter that can assess how the relationship between streamflow and sediment concentration or load changes over time in response to a wide variety of natural and anthropogenic watershed disturbances or long-term changes. The filter operates by updating parameter values using a recursive Bayesian design that responds to 1 day-ahead forecast errors while also accounting for observational noise. The estimated time series of rating curve parameters can then be used to diagnose multiscale (daily-decadal) variability in sediment yield after accounting for fluctuations in streamflow. The technique is applied in a case study examining changes in turbidity load, a proxy for sediment load, in the Esopus Creek watershed, part of the New York City drinking water supply system. The results show that turbidity load exhibits a complex array of variability across time scales. The DLM highlights flood event-driven positive hysteresis, where turbidity load remained elevated for months after large flood events, as a major component of dynamic behavior in the rating curve relationship. The DLM also produces more accurate 1 day-ahead loading forecasts compared to other static and time-varying rating curve methods. The results suggest that DLMs provide a useful tool for diagnosing changes in sediment-discharge relationships over time and may help identify variability in sediment concentrations and loads that can be used to inform dynamic water quality management.

  19. The effects of wind and rainfall on suspended sediment concentration related to the 2004 Indian Ocean tsunami

    International Nuclear Information System (INIS)

    Zhang Xinfeng; Tang Danling; Li Zizhen; Zhang Fengpan


    The effects of rainfall and wind speed on the dynamics of suspended sediment concentration (SSC), during the 2004 Indian Ocean tsunami, were analyzed using spatial statistical models. The results showed a positive effect of wind speed on SSC, and inconsistent effects (positive and negative) of rainfall on SSC. The effects of wind speed and rainfall on SSC weakened immediately around the tsunami, indicating tsunami-caused floods and earthquake-induced shaking may have suddenly disturbed the ocean-atmosphere interaction processes, and thus weakened the effects of wind speed and rainfall on SSC. Wind speed and rainfall increased markedly, and reached their maximum values immediately after the tsunami week. Rainfall at this particular week exceeded twice the average for the same period over the previous 4 years. The tsunami-affected air-sea interactions may have increased both wind speed and rainfall immediately after the tsunami week, which directly lead to the variations in SSC.

  20. Strategies and equipment for sampling suspended sediment and associated toxic chemicals in large rivers - with emphasis on the Mississippi River (United States)

    Meade, R.H.; Stevens, H.H.


    A Lagrangian strategy for sampling large rivers, which was developed and tested in the Orinoco and Amazon Rivers of South America during the early 1980s, is now being applied to the study of toxic chemicals in the Mississippi River. A series of 15-20 cross-sections of the Mississippi mainstem and its principal tributaries is sampled by boat in downstream sequence, beginning upriver of St. Louis and concluding downriver of New Orleans 3 weeks later. The timing of the downstream sampling sequence approximates the travel time of the river water. Samples at each cross-section are discharge-weighted to provide concentrations of dissolved and suspended constituents that are converted to fluxes. Water-sediment mixtures are collected from 10-40 equally spaced points across the river width by sequential depth integration at a uniform vertical transit rate. Essential equipment includes (i) a hydraulic winch, for sensitive control of vertical transit rates, and (ii) a collapsible-bag sampler, which allows integrated samples to be collected at all depths in the river. A section is usually sampled in 4-8 h, for a total sample recovery of 100-120 l. Sampled concentrations of suspended silt and clay are reproducible within 3%.

  1. Simulation of the transport of suspended particulate matter in the Rio de la Plata

    Energy Technology Data Exchange (ETDEWEB)

    Hausstein, H.


    Numerical simulations of the transport of Suspended Particulate Matter in the Rio de la Plata estuary were performed with a three dimensional model for coastal waters driven by wave sand currents. Aturbulence based flocculation approach is implemented to the model. The model is for the first time applied under heavy conditions, since the Rio de la Plata has discharges up to 25000 m{sup 3}/s and SPM concentrations up to 300-400 mg/l. Such concentrations are also difficult to compute from satellite measurements. SeaWiFs satellite images served for the validation of the model results. The model is able to reproduce the shape and the position of the front as well as the zone of the turbidity maximum. It also identifies the zones of erosion and deposition which is of significant importance because of the dense ship traffic along the navigational channels towards Buenos Aires and the cities upstream the rivers. (orig.)

  2. Use of multispectral satellite remote sensing to assess mixing of suspended sediment downstream of large river confluences (United States)

    Umar, M.; Rhoads, Bruce L.; Greenberg, Jonathan A.


    Although past work has noted that contrasts in turbidity often are detectable on remotely sensed images of rivers downstream from confluences, no systematic methodology has been developed for assessing mixing over distance of confluent flows with differing surficial suspended sediment concentrations (SSSC). In contrast to field measurements of mixing below confluences, satellite remote-sensing can provide detailed information on spatial distributions of SSSC over long distances. This paper presents a methodology that uses remote-sensing data to estimate spatial patterns of SSSC downstream of confluences along large rivers and to determine changes in the amount of mixing over distance from confluences. The method develops a calibrated Random Forest (RF) model by relating training SSSC data from river gaging stations to derived spectral indices for the pixels corresponding to gaging-station locations. The calibrated model is then used to predict SSSC values for every river pixel in a remotely sensed image, which provides the basis for mapping of spatial variability in SSSCs along the river. The pixel data are used to estimate average surficial values of SSSC at cross sections spaced uniformly along the river. Based on the cross-section data, a mixing metric is computed for each cross section. The spatial pattern of change in this metric over distance can be used to define rates and length scales of surficial mixing of suspended sediment downstream of a confluence. This type of information is useful for exploring the potential influence of various controlling factors on mixing downstream of confluences, for evaluating how mixing in a river system varies over time and space, and for determining how these variations influence water quality and ecological conditions along the river.

  3. A Numerical Study of Hydrodynamics and Sediment Transport in Fourleague Bay, Louisiana (United States)

    Hu, K.; Chen, Q. J.; Xu, K.; Bentley, S. J.; WANG, J.


    Fourleague Bay is a shallow and vertically well-mixed estuary in south-central Louisiana. This estuary is highly impacted by wind (e.g., cold fronts and tropical storms), river discharge from the Atchafalaya River and tides from the Gulf of Mexico, and is being used as an analog site to study impacts of sediment-diversion restoration strategies in the Mississippi River Delta. In this study, a coupled flow-wave Delft3D model was setup and applied to study hydrodynamics and sediment transport in this area. The model grid size is 1071x631 with a 50-m resolution in the bay. Vegetation is considered by rigid cylinders in both flow and wave modules. The offshore water level boundary conditions were provided by a Gulf-scale Delft3D model. Model parameters, especially for cohesive sediment transport such as settling velocity, erosion rate and critical bottom shear stress, were calibrated using the field observation data during three seasons from May 2015 to March 2016. The modeled water levels, currents, significant wave heights and suspended sediment concentrations agreed fairly well with measurements, which suggests a reasonable model performance. Seasonal variations were analyzed based on different scenarios. A series of numerical experiments were set up to quantify the contributions of different factors, such as river discharge, tides and waves to sediment transport in this area. This model will be further applied to be part of a landscape ecosystem model to test landscape and population change over time with manipulations to sediment delivery. This study was funded by the National Science Foundation (SEES-1427389 and CCF-1539567).

  4. Transport and deposition of asbestos-rich sediment in the Sumas River, Whatcom County, Washington (United States)

    Curran, Christopher A.; Anderson, Scott W.; Barbash, Jack E.; Magirl, Christopher S.; Cox, Stephen E.; Norton, Katherine K.; Gendaszek, Andrew S.; Spanjer, Andrew R.; Foreman, James R.


    Heavy sediment loads in the Sumas River of Whatcom County, Washington, increase seasonal turbidity and cause locally acute sedimentation. Most sediment in the Sumas River is derived from a deep-seated landslide of serpentinite that is located on Sumas Mountain and drained by Swift Creek, a tributary to the Sumas River. This mafic sediment contains high amounts of naturally occurring asbestiform chrysotile. A known human-health hazard, asbestiform chrysotile comprises 0.25–37 percent, by mass, of the total suspended sediment sampled from the Sumas River as part of this study, which included part of water year 2011 and all of water years 2012 and 2013. The suspended-sediment load in the Sumas River at South Pass Road, 0.6 kilometers (km) downstream of the confluence with Swift Creek, was 22,000 tonnes (t) in water year 2012 and 49,000 t in water year 2013. The suspended‑sediment load at Telegraph Road, 18.8 km downstream of the Swift Creek confluence, was 22,000 t in water year 2012 and 27,000 t in water year 2013. Although hydrologic conditions during the study were wetter than normal overall, the 2-year flood peak was only modestly exceeded in water years 2011 and 2013; runoff‑driven geomorphic disturbance to the watershed, which might have involved mass wasting from the landslide, seemed unexceptional. In water year 2012, flood peaks were modest, and the annual streamflow was normal. The fact that suspended-sediment loads in water year 2012 were equivalent at sites 0.6 and 18.8 km downstream of the sediment source indicates that the conservation of suspended‑sediment load can occur under normal hydrologic conditions. The substantial decrease in suspended-sediment load in the downstream direction in water year 2013 was attributed to either sedimentation in the intervening river reach, transfer to bedload as an alternate mode of sediment transport, or both.The sediment in the Sumas River is distinct from sediment in most other river systems because of the

  5. Swing-attenuation for a quadrotor transporting a cable-suspended payload. (United States)

    Guerrero-Sánchez, M Eusebia; Mercado-Ravell, D Alberto; Lozano, Rogelio; García-Beltrán, C Daniel


    This paper presents the problem of safe and fast transportation of packages by an Unmanned Aerial Vehicle (UAV) kind quadrotor. A mathematical model and a control strategy for a special class of underactuated mechanical systems, composed of a quadrotor transporting a cable-suspended payload, are proposed. The Euler-Lagrange formulation is used to obtain the dynamic model of the system, where the integrated dynamics of the quadrotor, cable and payload are considered. An Interconnection and Damping Assignment-Passivity Based Control (IDA-PBC) is chosen because of its inherent robustness against parametric uncertainty and unmodeled dynamics. Two cases are considered to obtain two different control laws, in the first case, the designed control law depends on the swing angle of the payload, in the second case the control law does not depend on it. The control objective is to transport the payload from point to point, with swing reduction along trajectory. Experimental results using monocular vision based navigation are shown to evaluate the proposed control law. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  6. Field evaluation of the error arising from inadequate time averaging in the standard use of depth-integrating suspended-sediment samplers (United States)

    Topping, David J.; Rubin, David M.; Wright, Scott A.; Melis, Theodore S.


    Several common methods for measuring suspended-sediment concentration in rivers in the United States use depth-integrating samplers to collect a velocity-weighted suspended-sediment sample in a subsample of a river cross section. Because depth-integrating samplers are always moving through the water column as they collect a sample, and can collect only a limited volume of water and suspended sediment, they collect only minimally time-averaged data. Four sources of error exist in the field use of these samplers: (1) bed contamination, (2) pressure-driven inrush, (3) inadequate sampling of the cross-stream spatial structure in suspended-sediment concentration, and (4) inadequate time averaging. The first two of these errors arise from misuse of suspended-sediment samplers, and the third has been the subject of previous study using data collected in the sand-bedded Middle Loup River in Nebraska. Of these four sources of error, the least understood source of error arises from the fact that depth-integrating samplers collect only minimally time-averaged data. To evaluate this fourth source of error, we collected suspended-sediment data between 1995 and 2007 at four sites on the Colorado River in Utah and Arizona, using a P-61 suspended-sediment sampler deployed in both point- and one-way depth-integrating modes, and D-96-A1 and D-77 bag-type depth-integrating suspended-sediment samplers. These data indicate that the minimal duration of time averaging during standard field operation of depth-integrating samplers leads to an error that is comparable in magnitude to that arising from inadequate sampling of the cross-stream spatial structure in suspended-sediment concentration. This random error arising from inadequate time averaging is positively correlated with grain size and does not largely depend on flow conditions or, for a given size class of suspended sediment, on elevation above the bed. Averaging over time scales >1 minute is the likely minimum duration required

  7. Modelling of Sediment Transport in Beris Fishery Port

    Directory of Open Access Journals (Sweden)

    Samira Ardani


    Full Text Available In this paper, the large amount of sedimentation and the resultant shoreline advancements at the breakwaters of Beris Fishery Port are studied. A series of numerical modeling of waves, sediment transport, and shoreline changes were conducted to predict the complicated equilibrium shoreline. The outputs show that the nearshore directions of wave components are not perpendicular to the coast which reveals the existence of longshore currents and consequently sediment transport along the bay. Considering the dynamic equilibrium condition of the bay, the effect of the existing sediment resources in the studied area is also investigated. The study also shows that in spite of the change of the diffraction point of Beris Bay after the construction of the fishery port, the bay is approaching its dynamic equilibrium condition, and the shoreline advancement behind secondary breakwater will stop before blocking the entrance of the port. The probable solutions to overcome the sedimentation problem at the main breakwater are also discussed.

  8. Radionuclides deposition and fine sediment transport in a forested watershed, central Japan (United States)

    Nam, S.; Gomi, T.; Kato, H.; Tesfaye, T.; Onda, Y.


    We investigated radionuclides deposition and fine sediment transport in a 13 ha headwater watershed, Tochigi prefecture, located in 98.94 km north of Tokyo. The study site was within Karasawa experimental forest, Tokyo University of Agriculture and Technology. We conducted fingerprinting approach, based on the activities of fallout radionuclides, including caesium-134 (Cs-134) caesium-137 (Cs-137) and excess lead-210 (Pb-210ex). For indentifying specific sources of fine sediment, we sampled tree, soil on forested floor, soil on logging road surface, stream bed and stream banks. We investigated the radionuclides (i.e., as Cs-134, Cs-137 and Pb-210ex) deposition on tree after accident of nuclear power plants on March 11, 2011. We sampled fruits, leaves, branches, stems, barks on Japanese cedar (Sugi) and Japanese cypress (Hinoki). To analyze the samples, gammaray spectrometry was performed at a laboratory at the University of Tsukuba (Tsukuba City, Japan) using n-type coaxial low-energy HPGe gamma detectors (EGC-200-R and EGC25-195-R of EURYSIS Co., Lingolsheim, France) coupled with a multichannel analyzer. We also collected soil samples under the forest canopy in various soil depths from 2, 5, 10, 20, 30 cm along transect of hillslopes. Samples at forest road were collected road segments crossing on the middle section of monitoring watersheds. Fine sediment transport in the streams were collected at the outlet of 13 ha watersheds using integrated suspended sediment samplers. This study indicates the some portion of radio nuclide potentially remained on the tree surface. Part of the deposited radionuclides attached to soil particles and transported to the streams. Most of the fine sediment can be transported on road surface and/or near stream side (riparian zones).

  9. Influence of near-bottom re-suspended sediment on benthic light availability

    DEFF Research Database (Denmark)

    Pedersen, Troels Møller; Gallegos, Charles L.; Nielsen, Søren Laurentius


    in which nutrient loading occurs primarily by groundwater input, that is, without strong river inputs of sediment. Alteration of bottomsediment texture, organic content, and bulk density by organic loading has been well documented. Here we report the effect of sedimentre-suspension on near...

  10. Saturation Concentrations of Suspended Fine Sediment : Computations with the Prandtl Mixing-Length Model

    NARCIS (Netherlands)

    Kranenburg, C.


    Adopting a 1DV numerical model including the standard k-eps turbulence model, Winterwerp et al. (1999) calculated a saturation concentration for an initially uniform distribution of fine sediment concentration in steady flow. At concentrations exceeding the saturation concentration the concentration

  11. Spatial patterns of suspended sediment yields in a humid tropical watershed in Costa Rica (United States)

    Krishnaswamy, Jagdish; Richter, Daniel D.; Halpin, Patrick N.; Hofmockel, Michael S.


    An Erratum has been published for this article in Hydrological Processes 16(5) 2002, 1130-1131.Humid tropical regions are often characterized by extreme variability of fluvial processes. The Rio Terraba drains the largest river basin, covering 4767 km2, in Costa Rica. Mean annual rainfall is 3139+/-419sd mm and mean annual discharge is 2168+/-492sd mm (1971-88). Loss of forest cover, high rainfall erosivity and geomorphologic instability all have led to considerable degradation of soil and water resources at local to basin scales. Parametric and non-parametric statistical methods were used to estimate sediment yields.In the Terraba basin, sediment yields per unit area increase from the headwaters to the basin mouth, and the trend is generally robust towards choice of methods (parametric and LOESS) used. This is in contrast to a general view that deposition typically exceeds sediment delivery with increase in basin size. The specific sediment yield increases from 112+/-11·4sd t km-2 year-1 (at 317·9 km2 on a major headwater tributary) to 404+/-141·7sd t km-2 year7400 MJ mm hasediment delivery ratio increases downstream with increasing basin area.