Testing distributed soil erosion and sediment delivery models using137Cs measurements

Evaluating the usefulness of spatially-distributed soil erosion and sediment delivery models is inherently difficult. Complications stem from the uncertainty in models and measurements of system responses, as well as from the scarcity of commensurable spatial data for model testing. Here, we present an approach for evaluating distributed soil erosion and sediment delivery models, which incorporates sediment source fingerprinting into model testing within a stochastic framework. We applied the Generalized Likelihood Uncertainty Estimation (GLUE) methodology to the Sediment Delivery Distributed (SEDD) model for the Mortes River catchment (~6600 km&#178;) in Southeast Brazil. Sediment concentration measurements were used to estimate long-term sediment loads with a sediment rating curve. Regression uncertainty was propagated with posterior simulations of model coefficients. A Monte Carlo simulation was used to generate SEDD model realizations, which were compared against limits of acceptability of model errors derived from the uncertainty in the curve-estimated sediment loads. The models usefulness for identifying the sediment sources in the catchment was assessed by evaluating behavioral model realizations against sediment fingerprinting source apportionments. Accordingly, we developed a hierarchical tributary sampling design, in which sink sediments were sampled from multiple nodes in the main river channel. The relative contributions of the main sub-catchments in the basin were subsequently estimated by solving the fingerprinting un-mixing model with a Monte Carlo simulation. Results indicated that gauging station measurements of sediment loads were fairly uncertain (average annual specific sediment yields = 0.47 &#8211; 11.95 ton ha-1 yr-1). This led to 23.4 % of SEDD model realizations being considered behavioral system representations. Spatially-distributed estimates of sediment delivery to water courses were also highly uncertain, as grid-based absolute errors of SEDD results were hundredfold the median of the predictions. A comparison of SEDD outputs and fingerprinting source apportionments revealed an overall agreement between modeled contributions from individual sub-catchments to sediment loads, although some large discrepancies were found in a specific tributary. From a falsificationist perspective, the SEDD model could not be rejected, as many model realizations were behavioral. The partial agreement between fingerprinting and SEDD results provide some conditional corroboration of the models capability to identify the sources of sediments in the catchment, at least with some degree of spatial aggregation. However, the uncertainty in the grid-based outputs might dispute the models usefulness for actually quantifying sediment dynamics under the testing conditions. For management purposes, both SEDD and fingerprinting results indicated that most of the sediments reaching the hydroelectric power plant reservoir located at the outlet of the Mortes River originated from mid and upper catchment tributaries. The convergence of model results therefore evince that reducing reservoir sedimentation rates requires widespread soil conservation efforts throughout the catchment, instead of local/proximal interventions. Ultimately, we have shown how sediment source fingerprinting can be incorporated into the evaluation of spatially-distributed soil erosion and sediment delivery models while considering the uncertainty in both models and observational data.

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Enhancement of the SATEEC Soil Erosion and Sediment Modeling System with Better Sediment Delivery Ratio Module

10.13031/2013.22928 ◽

2007 ◽

Author(s):

Ki-Sung Kim ◽

Kyoung Jae Lim ◽

Joongdae Choi ◽

Bernie Engel ◽

Ji-Hong Jeon ◽

...

Keyword(s):

Soil Erosion ◽

Delivery Ratio ◽

Sediment Delivery Ratio ◽

Sediment Delivery

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Influence of land management on soil erosion, connectivity, and sediment delivery in agricultural catchments: Closing the sediment budget

Land Degradation and Development ◽

10.1002/ldr.3413 ◽

2019 ◽

Vol 30 (18) ◽

pp. 2257-2271 ◽

Cited By ~ 2

Author(s):

Sophie C. Sherriff ◽

John S. Rowan ◽

Owen Fenton ◽

Phil Jordan ◽

Daire Ó hUallacháin

Keyword(s):

Soil Erosion ◽

Land Management ◽

Sediment Budget ◽

Sediment Delivery ◽

Agricultural Catchments

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Soil Sediment Loading and Related Environmental Impacts from Farms

Oxford Research Encyclopedia of Environmental Science ◽

10.1093/acrefore/9780199389414.013.267 ◽

2017 ◽

Author(s):

Vito Ferro

Keyword(s):

Organic Matter ◽

Spatial Distribution ◽

Soil Erosion ◽

Sediment Yield ◽

Water Storage ◽

Sediment Deposition ◽

Delivery Ratio ◽

Sediment Delivery Ratio ◽

Sediment Delivery ◽

Soil Particles

Beyond damage to rainfed agricultural and forestry ecosystems, soil erosion due to water affects surrounding environments. Large amounts of eroded soil are deposited in streams, lakes, and other ecosystems. The most costly off-site damages occur when eroded particles, transported along the hillslopes of a basin, arrive at the river network or are deposited in lakes. The negative effects of soil erosion include water pollution and siltation, organic matter loss, nutrient loss, and reduction in water storage capacity. Sediment deposition raises the bottom of waterways, making them more prone to overflowing and flooding. Sediments contaminate water ecosystems with soil particles and the fertilizer and pesticide chemicals they contain. Siltation of reservoirs and dams reduces water storage, increases the maintenance cost of dams, and shortens the lifetime of reservoirs. Sediment yield is the quantity of transported sediments, in a given time interval, from eroding sources through the hillslopes and river network to a basin outlet. Chemicals can also be transported together with the eroded sediments. Sediment deposition inside a reservoir reduces the water storage of a dam. The prediction of sediment yield can be carried out by coupling an erosion model with a mathematical operator which expresses the sediment transport efficiency of the hillslopes and the channel network. The sediment lag between sediment yield and erosion can be simply represented by the sediment delivery ratio, which can be calculated at the outlet of the considered basin, or by using a distributed approach. The former procedure couples the evaluation of basin soil loss with an estimate of the sediment delivery ratio SDRW for the whole watershed. The latter procedure requires that the watershed be discretized into morphological units, areas having a constant steepness and a clearly defined length, for which the corresponding sediment delivery ratio is calculated. When rainfall reaches the surface horizon of the soil, some pollutants are desorbed and go into solution while others remain adsorbed and move with soil particles. The spatial distribution of the loading of nitrogen, phosphorous, and total organic carbon can be deduced using the spatial distribution of sediment yield and the pollutant content measured on soil samples. The enrichment concept is applied to clay, organic matter, and all pollutants adsorbed by soil particles, such as nitrogen and phosphorous. Knowledge of both the rate and pattern of sediment deposition in a reservoir is required to establish the remedial strategies which may be practicable. Repeated reservoir capacity surveys are used to determine the total volume occupied by sediment, the sedimentation pattern, and the shift in the stage-area and stage-storage curves. By converting the sedimentation volume to sediment mass, on the basis of estimated or measured bulk density, and correcting for trap efficiency, the sediment yield from the basin can be computed.

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Estimating sediment delivery ratio by stream slope and relief ratio

MATEC Web of Conferences ◽

10.1051/matecconf/201819202040 ◽

2018 ◽

Vol 192 ◽

pp. 02040 ◽

Cited By ~ 1

Author(s):

Kieu Anh Nguyen ◽

Walter Chen

Keyword(s):

Soil Erosion ◽

Storage Capacity ◽

Length Ratio ◽

Delivery Ratio ◽

Sediment Delivery Ratio ◽

Sediment Delivery ◽

Transportation Process ◽

Shihmen Reservoir ◽

Reservoir Watershed ◽

Steep Terrain

Nowadays, the storage capacity of a reservoir reduced by sediment deposition is a concern of many countries in the world. Therefore, understanding the soil erosion and transportation process is a significant matter, which helps to manage and prevent sediments entering the reservoir. The main objective of this study is to examine the sediments reaching the outlet of a basin by empirical sediment delivery ratio (SDR) equations and the gross soil erosion. The Shihmen reservoir watershed is used as the study area. Because steep terrain is a characteristic feature of the study area, two SDR models that depend on the slope of the mainstream channel and the relief-length ratio of the watershed are chosen. It is found that the Maner (1958) model, which uses the relief-length ratio, is the better model of the two. We believe that this empirical research improves our understanding of the sediment delivery process occurring in the study area.

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Soil erosion and sediment delivery in a mountain catchment under scenarios of land use change using a spatially distributed numerical model

Hydrology and Earth System Sciences ◽

10.5194/hess-16-1321-2012 ◽

2012 ◽

Vol 16 (5) ◽

pp. 1321-1334 ◽

Cited By ~ 54

Author(s):

L. C. Alatorre ◽

S. Beguería ◽

N. Lana-Renault ◽

A. Navas ◽

J. M. García-Ruiz

Keyword(s):

Land Use ◽

Soil Erosion ◽

Sediment Yield ◽

Model Calibration ◽

Global Optimum ◽

Model Parameters ◽

Sediment Delivery ◽

Yield Data ◽

Good Convergence ◽

Spatially Distributed

Abstract. Soil erosion and sediment yield are strongly affected by land use/land cover (LULC). Spatially distributed erosion models are of great interest to assess the expected effect of LULC changes on soil erosion and sediment yield. However, they can only be applied if spatially distributed data is available for their calibration. In this study the soil erosion and sediment delivery model WATEM/SEDEM was applied to a small (2.84 km2) experimental catchment in the Central Spanish Pyrenees. Model calibration was performed based on a dataset of soil redistribution rates derived from point 137Cs inventories, allowing capture differences per land use in the main model parameters. Model calibration showed a good convergence to a global optimum in the parameter space, which was not possible to attain if only external (not spatially distributed) sediment yield data were available. Validation of the model results against seven years of recorded sediment yield at the catchment outlet was satisfactory. Two LULC scenarios were then modeled to reproduce land use at the beginning of the twentieth century and a hypothetic future scenario, and to compare the simulation results to the current LULC situation. The results show a reduction of about one order of magnitude in gross erosion (3180 to 350 Mg yr−1) and sediment delivery (11.2 to 1.2 Mg yr−1 ha−1) during the last decades as a result of the abandonment of traditional land uses (mostly agriculture) and subsequent vegetation recolonization. The simulation also allowed assessing differences in the sediment sources and sinks within the catchment.

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Ephemeral gully erosion from agricultural regions in the Pacific Northwest, USA

Annals of Warsaw University of Life Sciences – SGGW Land Reclamation ◽

10.2478/v10060-008-0061-y ◽

2010 ◽

Vol 42 (1) ◽

pp. 23-29 ◽

Cited By ~ 3

Author(s):

Michael Barber ◽

Robert Mahler

Keyword(s):

High Resolution ◽

Soil Erosion ◽

Pacific Northwest ◽

Gully Erosion ◽

Aerial Imagery ◽

Sediment Delivery ◽

Ephemeral Gully ◽

The Pacific ◽

Ephemeral Gullies ◽

Agricultural Regions

Ephemeral gully erosion from agricultural regions in the Pacific Northwest, USA Soil erosion continues to be problematic financially and environmentally with the USEPA ranking sediment as one of the top ten pollutants of concern in the USA. One aspect of erosion often overlooked is the role of ephemeral gullies in terms of quantity of sediment produced and amount exported to nearby waterways. Current physically-based and empirical models are inadequate for predicting this type of erosion particularly at the watershed scale. A new methodology for predicting the quantity and location of sediment delivery was developed and tested via a case study. Aerial ephemeral gully erosion rates varied from 33.6 mton/km2 (0.15 U.S. tons/acre) in the Big Bear Creek basin to 88.4 mton/km2 (0.39 U.S. tons/acre) in the Middle Potlatch Creek basin representing 2.3 to 7.7% of the total surface sediment load. This information was used to develop a predictive Erosion Potential Index (EPI) that uses LANDSAT aerial imagery combined with readily available soils information and a digital elevation model to identify the most probably locations of ephemeral gully development. High resolution aerial imagery was used to quantify actual ephemeral gully locations which were then compared to the EPI predicted locations to verify the procedure. High resolution aerial imagery was also used to quantify the amounts of soil erosion from ephemeral gullies in basins of the Potlatch River system.

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Spatial redistribution of Cs-137 and soil erosion on Orléans Island, Québec

Canadian Journal of Soil Science ◽

10.4141/cjss92-045 ◽

1992 ◽

Vol 72 (4) ◽

pp. 543-554 ◽

Cited By ~ 9

Author(s):

Claude Bernard ◽

Marc R. Laverdière

Keyword(s):

Soil Erosion ◽

Quebec City ◽

Delivery Ratio ◽

Sediment Delivery ◽

Soil Movement ◽

Movement Rates ◽

Spatial Redistribution ◽

Soil Redeposition ◽

Soil Accumulation ◽

Soil Losses

Cs-137 redistribution data have been used to estimate the extent and the pattern of long-term soil erosion in the Québec City area. Mean annual net soil movements ranging from a deposition of 10.8 t ha−1 yr−1 to a loss of 31.8 t ha−1 yr−1 were estimated. The slope steepness and the land use significantly influenced the estimated rates of soil movement, while soil texture was less important, probably because of the soils’ sandy texture or the high content of organic carbon, which kept their erodibility low. The net soil losses estimated from Cs-137 data were consistently higher than those predicted by the USLE. Besides net soil losses, it was possible to estimate separately the magnitude of soil detachment and soil deposition. Two–thirds of the stations sampled experienced net soil loss while the remaining third showed evidence of soil accumulation. These data suggest that the small net soil losses measured for low erosive conditions (flat slopes, dairy farming) result from important soil redeposition rates as much as from small soil detachment rates. Cs-137 redistribution data not only produce reliable estimates of soil movement rates, but also allow enhanced estimates of the agronomic and environmental impacts of soil erosion.Key words: Cs-137, erosion, sedimentation, USLE, sediment delivery ratio

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Land use/land cover change effect on Soil erosion and Sediment Delivery on Winike Watershed, Omo Gibe Basin, Ethiopia

10.21203/rs.2.19417/v1 ◽

2019 ◽

Author(s):

Abreham Berta Aneseyee

Keyword(s):

Land Use ◽

Soil Erosion ◽

Land Cover ◽

Land Cover Change ◽

Soil Loss ◽

Management Practices ◽

Delivery Ratio ◽

Land Use Land Cover ◽

Sediment Delivery ◽

Sediment Export

Abstract Background: Information on soil loss and sediment export is essential to identify hotspots of soil erosion for conservation interventions in a given watershed. This study aims at investigating the dynamic of soil loss and sediment export associated with land use/land cover change and identifies soil loss hotspot areas in Winike watershed of Omo-gibe basin of Ethiopia. Spatial data collected from satellite images, topographic maps, meteorological and soil data were analyzed. Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) of sediment delivery ratio (SDR) model was used based on analysis of land use/land cover maps and RUSLE factors. Result: The results showed that total soil loss increased from 774.86 thousand tons in 1988 to 951.21 thousand tons in 2018 while the corresponding sediment export increased by 3.85 thousand tons in the same period. These were subsequently investigated in each land-use type. Cultivated fields generated the highest soil erosion rate, which increased by 10.02 t/ha/year in 1988 to 43.48 t/ha/year in 2018. This corresponds with the expansion of the cultivated area that increased from 44.95 thousand ha in 1988 to 59.79 thousand ha in 2018. This is logical as the correlation between soil loss and sediment delivery and expansion of cultivated area is highly significant (p<0.01). Sub-watershed six (SW-6) generated the highest soil loss (62.77 t/ha/year) and sediment export 16.69 t/ha/year, followed by Sub-watershed ten (SW-10) that are situated in the upland plateau. Conversely, the lower reaches of the watershed are under dense vegetation cover and experiencing less erosion. Conclusion: Overall, the changes in land use/land cover affect significantly the soil erosion and sediment export dynamism. This research is used to identify an area to prioritize the watershed for immediate management practices. Thus, land use policy measures need to be enforced to protect the hydropower generation dams at downstream and the ecosystem at the watershed.

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