Quantification of soil redistribution and sediment budget in a Canadian watershed from fallout caesium-137 (137Cs) data

2002 ◽  
Vol 82 (4) ◽  
pp. 423-431 ◽  
Author(s):  
L. Mabit ◽  
C. Bernard ◽  
M R Laverdière
Keyword(s):  
Soil Erosion ◽  
Sampling Strategy ◽  
Delivery Ratio ◽  
Watershed Scale ◽  
Eastern Canada ◽  
Sediment Delivery ◽  
Soil Redistribution ◽  
Average Loss ◽  
Data Extrapolation ◽  
Sediment Export

The intensification and specialization of agriculture that took place in the past decades have resulted in soil and water degradation in several areas of eastern Canada. Most studies on soil erosion in Quebec have been conducted at the experimental plot scale. Although this approach generates precise data, extrapolation at the field or watershed scale is difficult. In this study, caesium-137 (137Cs) was used to investigate the spatial extent and severity of soil erosion for an 80-ha watershed in Southeastern Quebec (cultivated area = 75 ha). Soil samples were collected based on a 25 (30 m grid and revealed soil redistribution rates ranging from -20 to +12 Mg ha-1 yr-1. From radiocaesium measurements, it was estimated that the experimental watershed experienced an average loss of 3.0 Mg ha-1 yr-1 with net sediment export of 2.8 Mg ha-1 yr-1 and a sediment delivery ratio of 93%. Snowmelt erosion is believed to have played an important role in the soil redistribution in this small watershed. Changing sampling strategy was tested (50 x 60 m and 100 x 120 m grid rather than 25 x 30 m) and only minor changes were noticed on soil erosion and sediment production estimates, when samples corresponding to the 50 x 60 m grid were used. Key words: Caesium-137 (137Cs), watershed, water erosion, snowmelt erosion, sampling strategy

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

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.

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

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

Soil Sediment Loading and Related Environmental Impacts from Farms

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.

scholarly journals Estimating sediment delivery ratio by stream slope and relief ratio

2018 ◽  
Vol 192 ◽  
pp. 02040 ◽  
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.

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

1992 ◽  
Vol 72 (4) ◽  
pp. 543-554 ◽  
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

scholarly journals Assessment of uncertainties in soil erosion and sediment yield estiamtes at ungauged basins: an application to the Garra River basin, India

2017 ◽  
Author(s):  
Somil Swarnkar ◽  
Anshu Malini ◽  
Shivam Tripathi ◽  
Rajiv Sinha
Keyword(s):  
Soil Erosion ◽  
River Basin ◽  
Sediment Yield ◽  
Uncertainty Propagation ◽  
River Basins ◽  
Large River ◽  
Delivery Ratio ◽  
Mountainous Region ◽  
Ungauged Basins ◽  
Sediment Delivery

Abstract. High soil erosion and excessive sediment load are serious problems in several Himalayan River basins. To apply mitigation procedures, precise estimation of soil erosion and sediment yield with associated uncertainties are needed. Here, Revised Universal Soil Loss Equation (RUSLE) and Sediment Delivery Ratio (SDR) equations are used to estimate the spatial pattern of soil erosion (SE) and sediment yield (SY) in the Garra River basin, a small Himalayan tributary of River Ganga. A methodology is proposed for quantifying and propagating uncertainties in SE, SDR and SY estimates. Expressions for uncertainty propagation are derived by first-order uncertainty analysis, making the method viable even for large river basins. The methodology is applied to investigate the relative importance of different RUSLE factors in estimating the magnitude and uncertainties of SE over two distinct morpho-climatic regimes of the Garra River basin, namely, upper mountainous region &amp; lower alluvial plains. The results suggest that average SE in the basin falls in very high category (20.4 ± 4.1 t/ha/y) with higher values in the upper mountainous region (84.4 ± 13.9 t/ha/y) than in the lower alluvial plains (17.7 ± 3.6 t/ha/y). Furthermore, the topographic steepness (LS) and crop practice (CP) factors exhibit higher uncertainties than other RUSLE factors. The annual average SY is estimated at two locations in the basin – Nanak Sagar dam (NSD) for the period 1962–2008 and Husepur gauging station (HGS) for 1987–2002. The SY at NSD and HGS are estimated to be 8.0 ± 1.4 × 105 t/y and 7.9 ± 1.7 ×106 t/y, respectively, and the estimated 90 % confidence interval contains the observed values 6.4 × 105 t/y and 7.2 × 106 t/y. The study demonstrated the usefulness of the proposed methodology for quantifying uncertainty in SE and SY estimates at ungauged basins.

scholarly journals MODELLING RESERVOIR SEDIMENTATION AT BIN EL OUIDANE DAM, MOROCCO

AGROFOR ◽  
2018 ◽  
Vol 2 (1) ◽  
Author(s):  
El Mouatassime SABRI ◽  
Ahmed BOUKDIR ◽  
Rachid El MASLOUHI ◽  
Mustapha MABROUKI ◽  
Abdellah EL MAHBOUL ◽  
...  
Keyword(s):  
Information System ◽  
Soil Erosion ◽  
Sediment Yield ◽  
Delivery Ratio ◽  
Reservoir Sedimentation ◽  
Mountainous Areas ◽  
Sediment Delivery Ratio ◽  
Sediment Delivery ◽  
Sparse Vegetation ◽  
Bin El Ouidane

This study was conducted in the Oued El Abid watershed upstream of the Bin ElOuidane dam, in Tadla-Azilal province (Morocco) to quantify the dam siltationrates. To assess the annual soil erosion and the sediment yield the universal soilloss equation (USLE) was used. A geographic information system (GIS) was usedto generate and integrate maps of the USLE factors. A spatial distribution of soilerosion in the Oued El Abid watershed was obtained. The soil erosion wasdetermined for each rural commune in order to identify the soil erosion hotspot andestimate the amount of soil that has been transported downstream (Bin El OuidaneDam). Soil erosion ranged from very limited values for flat and well covered areasto over 2100 t /ha/y in mountainous areas with sparse vegetation. The total annualsoil loss within the watershed is estimated at 19. 6 million tons per year. Anequation of sediment delivery ratio (SDR) based on river gradient was calculated.It was found that the value of SDR at the outlet of the watershed Oued El Abid was0. 65 with a sediment yield of 12. 74 million tons per year which affect thedurability of the dam.

scholarly journals Assessment of uncertainties in soil erosion and sediment yield estimates at ungauged basins: an application to the Garra River basin, India

2018 ◽  
Vol 22 (4) ◽  
pp. 2471-2485 ◽  
Author(s):  
Somil Swarnkar ◽  
Anshu Malini ◽  
Shivam Tripathi ◽  
Rajiv Sinha
Keyword(s):  
Soil Erosion ◽  
River Basin ◽  
Sediment Yield ◽  
Uncertainty Propagation ◽  
River Basins ◽  
Large River ◽  
Delivery Ratio ◽  
Mountainous Region ◽  
Ungauged Basins ◽  
Sediment Delivery

Abstract. High soil erosion and excessive sediment load are serious problems in several Himalayan river basins. To apply mitigation procedures, precise estimation of soil erosion and sediment yield with associated uncertainties are needed. Here, the revised universal soil loss equation (RUSLE) and the sediment delivery ratio (SDR) equations are used to estimate the spatial pattern of soil erosion (SE) and sediment yield (SY) in the Garra River basin, a small Himalayan tributary of the River Ganga. A methodology is proposed for quantifying and propagating uncertainties in SE, SDR and SY estimates. Expressions for uncertainty propagation are derived by first-order uncertainty analysis, making the method viable even for large river basins. The methodology is applied to investigate the relative importance of different RUSLE factors in estimating the magnitude and uncertainties in SE over two distinct morphoclimatic regimes of the Garra River basin, namely the upper mountainous region and the lower alluvial plains. Our results suggest that average SE in the basin is very high (23 ± 4.7 t ha−1 yr−1) with higher values in the upper mountainous region (92 ± 15.2 t ha−1 yr−1) compared to the lower alluvial plains (19.3 ± 4 t ha−1 yr−1). Furthermore, the topographic steepness (LS) and crop practice (CP) factors exhibit higher uncertainties than other RUSLE factors. The annual average SY is estimated at two locations in the basin – Nanak Sagar Dam (NSD) for the period 1962–2008 and Husepur gauging station (HGS) for 1987–2002. The SY at NSD and HGS are estimated to be 6.9 ± 1.2 × 105 t yr−1 and 6.7 ± 1.4 × 106 t yr−1, respectively, and the estimated 90 % interval contains the observed values of 6.4 × 105 t yr−1 and 7.2 × 106 t yr−1, respectively. The study demonstrated the usefulness of the proposed methodology for quantifying uncertainty in SE and SY estimates at ungauged basins.

scholarly journals Spatial Modeling of Sediment Export Rate with Rainfall Variability Scenario in Peusangan Watershed, Aceh Province

2021 ◽  
Vol 925 (1) ◽  
pp. 012026
Author(s):  
E Djunarsjah ◽  
M M Julian ◽  
A A Baskoro ◽  
N R Alfandi
Keyword(s):  
Erosion Rate ◽  
Rainfall Variability ◽  
Annual Number ◽  
Delivery Ratio ◽  
Water Runoff ◽  
Sediment Delivery ◽  
Export Rate ◽  
Aceh Province ◽  
Sediment Export

Abstract The rainfall affects the environmental interaction of watersheds and coastal areas. The high intensity of rain and water runoff will lift and carry particles in the watershed environment in the erosion process. This study estimates the total exports of sediment in Peusangan Watershed in the period 1995, 2005, 2015, and 2018 with rainfall variability scenarios. Total sediment exports are calculated from the erosion rate and sediment delivery ratio (SDR). Erosion rate modeling uses the RUSLE (Revised Universal Soil Loss Equation) that takes into account erosivity of rainfall, soil erodiability, topography, land cover, and land-use practices. While SDR is calculated based on its function as watershed area so that homogeneous value that causes the value of sediment export rate is directly proportional to the erosion rate value. The correlation between rainfall variability and sediment export rates is calculated based on rainfall variability correlation to erosion rate change. There is a direct relationship between rainfall variability and sediment export rates because the correlation coefficient is close to one. The rate of erosion in Peusangan watersheds falls into the light category based on the classification of erosion hazard levels according to the Ministry of Forestry in 1998. Based on the estimated rate of erosion and SDR, the total annual number of sediment exports obtained in the Peusangan watershed in 1995, 2005, 2015, and 2018 amounted to 1,066,027,426 tons, 909,914,623 tons, 1,075,759,133 tons, and 1,085,490,841 tons, respectively. Based on the spatial distribution of sediment export, Peusangan Watershed falls into the category of normal erosion.

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