scholarly journals Copula-Based Infilling Methods for Daily Suspended Sediment Loads

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1701
Author(s):  
Jenq-Tzong Shiau ◽  
Yu-Cheng Lien
Keyword(s):  
Suspended Sediment ◽  
Conditional Distribution ◽  
Sediment Load ◽  
Distribution Model ◽  
Rating Curve ◽  
Similar Frequency ◽  
Sediment Rating Curve ◽  
Sediment Loads ◽  
Recorded Data ◽  
Sediment Data

Less-frequent and inadequate sampling of sediment data has negatively impacted the long and continuous records required for the design and operation of hydraulic facilities. This data-scarcity problem is often found in most river basins of Taiwan. This study aims to propose a parsimonious probabilistic model based on copulas to infill daily suspended sediment loads using streamflow discharge. A copula-based bivariate distribution model of sediment and discharge of the paired recorded data is constructed first. The conditional distribution of sediment load given observed discharge is used to provide probabilistic estimation of sediment loads. In addition, four different methods based on the derived conditional distribution of sediment load are used to give single-value estimations. The obtained outcomes of these methods associated with the results of the traditional sediment rating curve are compared with recorded data and evaluated in terms of root mean square error (RMSE), mean absolute percentage error (MAPE), Nash-Sutcliffe efficiency (NSE), and modified Nash-Sutcliffe efficiency (MNSE). The proposed approach is applied to the Janshou station located in eastern Taiwan with recorded daily data for the period of 1960–2019. The results indicate that the infilled sediments by the sediment rating curve exhibit better performance in RMSE and NSE, while the copula-based methods outperform in MAPE and MNSE. Additionally, the infilled sediments by the copula-based methods preserve scattered characteristics of observed sediment-discharge relationships and exhibit similar frequency distributions to that of recorded sediment data.

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

2017 ◽  
Vol 48 ◽  
Author(s):  
Hossein Khaledian ◽  
Homayoun Faghih ◽  
Ata Amini
Keyword(s):  
Suspended Sediment ◽  
River Flow ◽  
Data Classification ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Low Flow ◽  
Rating Curve ◽  
Sediment Rating Curve ◽  
Curve Method ◽  
Sediment Data

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

Understanding watershed suspended sediment transport

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

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

Sediment and nutrient loadings to Lake Ontario: methodological arguments

1977 ◽  
Vol 14 (7) ◽  
pp. 1555-1565 ◽  
Author(s):  
Edwin D. Ongley ◽  
John G. Ralston ◽  
Richard L. Thomas
Keyword(s):  
Suspended Sediment ◽  
Sediment Load ◽  
Lake Ontario ◽  
Environmental Issues ◽  
Surveillance Data ◽  
Nutrient Loads ◽  
Suspended Sediment Load ◽  
Sampling Strategies ◽  
Sediment Loads ◽  
Sediment Data

Environmental issues frequently require values for sediment and nutrient loads in river systems. Except in rare instances, such values must be drawn from existing surveillance data which may not reflect sampling strategies pertinent to the issue at hand. In particular, the time variant and nonlinear relationships between discharge and both suspended sediment and sediment-related parameters such as phosphorus cannot be captured in detail by surveillance data, Nevertheless, such data collected routinely by the Ontario Ministry of the Environment accurately reflect the relative loadings both in terms of unit and total yields in five basins where detailed suspended sediment data are available. Although surveillance data underestimate the absolute values of suspended sediment loads calculated from detailed sediment information, these data do capture the relative monthly and seasonal contributions to annual suspended sediment load. A comparison of three methods for calculating annual unit and total loadings of suspended and solute components from surveillance information indicates that annual mean data convey information which is not significantly less adequate than monthly aggregations of data.

scholarly journals Prediction of sediment load by sediment rating curve and neural network (ANN) in El Kebir catchment, Algeria

2013 ◽  
Vol 122 (5) ◽  
pp. 1303-1312 ◽  
Author(s):  
Z A BOUKHRISSA ◽  
K KHANCHOUL ◽  
Y LE BISSONNAIS ◽  
M TOURKI
Keyword(s):  
Neural Network ◽  
Sediment Load ◽  
Rating Curve ◽  
Sediment Rating Curve

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

2021 ◽  
Author(s):  
Marcel van der Perk
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Sudden Increase ◽  
Rhine River ◽  
Rating Curve ◽  
Independent Evidence ◽  
Sediment Rating Curve ◽  
Suspended Sediment Concentrations

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

scholarly journals An application of adaptive cluster sampling for estimating total suspended sediment load

2009 ◽  
Vol 41 (1) ◽  
pp. 63-73 ◽  
Author(s):  
M. Arabkhedri ◽  
F. S. Lai ◽  
I. Noor-Akma ◽  
M. K. Mohamad-Roslan
Keyword(s):  
Suspended Sediment ◽  
Sediment Concentration ◽  
Cluster Sampling ◽  
Suspended Sediment Transport ◽  
Adaptive Cluster Sampling ◽  
Total Load ◽  
Sediment Rating Curve ◽  
Sediment Loads ◽  
Daily Concentration ◽  
Rating Curves

Suspended sediment transport in river for a particular period is a timescale finite population. This population shows natural aggregation tendencies in sediment concentration particularly during floods. Adaptive cluster sampling (ACS) can be potentially conducted for sampling from this rare clustered population and estimating total load. To illustrate the performance of ACS in sediment estimation, a comparative study was carried out in the Gorgan-Rood River, Iran, with around a 5 year daily concentration record. The total sediment loads estimated by ACS were statistically compared to the observed load, estimations of selection at list time (SALT) and conventional sediment rating curve with and without correction factors. The results suggest that none of the sediment rating curves produced accurate estimates, while both ACS and SALT showed satisfactory results at a semi-weekly sampling frequency. The best estimation obtained by the rating curves did not show a percent error better than −40%; however, ACS and SALT underestimated the load at less than 5%. The results of this study suggest ACS could improve river monitoring programs.

scholarly journals Sediment concentration rating curves for a monsoonal climate: upper Blue Nile

SOIL ◽  
2016 ◽  
Vol 2 (3) ◽  
pp. 337-349 ◽  
Author(s):  
Mamaru A. Moges ◽  
Fasikaw A. Zemale ◽  
Muluken L. Alemu ◽  
Getaneh K. Ayele ◽  
Dessalegn C. Dagnew ◽  
...  
Keyword(s):  
Geographical Area ◽  
Type Equation ◽  
Sediment Concentration ◽  
Rating Curve ◽  
Monsoon Period ◽  
Blue Nile ◽  
Sediment Loads ◽  
Blue Nile Basin ◽  
Rating Curves ◽  
Sediment Data

Abstract. Information on sediment concentration in rivers is important for design of reservoirs and for environmental applications. Because of the scarcity of continuous sediment data, methods have been developed to predict sediment loads based on few discontinuous measurements. Traditionally, loads are being predicted using rating curves that relate sediment load to discharge. The relationship assumes inherently a unique relationship between concentration and discharge and therefore although performing satisfactorily in predicting loads, it may be less suitable for predicting concentration. This is especially true in the Blue Nile Basin of Ethiopia where concentrations decrease for a given discharge with the progression of the rainy monsoon phase. The objective of this paper is to improve the sediment concentration predictions throughout the monsoon period for the Ethiopian highlands with a modified rating type equation. To capture the observed sediment concentration pattern, we assume that the sediment concentration was at the transport limit early in the rainy season and then decreases linearly with effective rainfall towards source-limited concentration. The modified concentration rating curve was calibrated for the four main rivers in the Lake Tana basin where sediment concentrations affect fish production and tourism. Then the scalability of the rating type equation was checked in three 100 ha watersheds for which historic data were available. The results show that for predicting sediment concentrations, the (modified) concentration rating curve was more accurate than the (standard) load rating curve as expected. In addition loads were predicted more accurately for three of the four rivers. We expect that after more extensive testing over a wider geographical area, the proposed concentration rating curve will offer improved predictions of sediment concentrations in monsoonal climates.

Fluvial Sedimentation in Southern Ontario

1975 ◽  
Vol 12 (11) ◽  
pp. 1813-1819 ◽  
Author(s):  
W. T. Dickinson ◽  
A. Scott ◽  
G. Wall
Keyword(s):  
Suspended Sediment ◽  
Drainage Density ◽  
Low Flow ◽  
Southern Ontario ◽  
Frequency Distributions ◽  
Sediment Yields ◽  
Sediment Loads ◽  
Fluvial Sedimentation ◽  
Sediment Data ◽  
Suspended Loads

Suspended sediment data for Southern Ontario stream have been analyzed with regard to areal and temporal patterns, characteristics of sediment concentrations, and relationships between sediment loads and watershed parameters. The range of annual suspended sediment yields for seven river basins is determined as 5250 to 175 000 kg/year/km2. The daily suspended loads exhibit highly skewed frequency distributions, with mean loads being equalled or exceeded less than 20% of the time and 50% of the annual load occurring during the months of March and April. It is demonstrated that sample loads collected during periods of low flow, and stream rankings determined from low flow data, are not indicative of the annual suspended sediment load picture. No simple model between suspended loads and such basin indices as relief ratio and drainage density is found to be satisfactory for prediction purposes.

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