Spatial distribution of soil erosion and sediment yield in the Koshi River Basin, Nepal: a case study of Triyuga watershed

2021 ◽  
Author(s):  
Belayneh Yigez ◽  
Donghong Xiong ◽  
Baojun Zhang ◽  
Yong Yuan ◽  
Muhammad Aslam Baig ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Soil Erosion ◽  
River Basin ◽  
Sediment Yield ◽  
Koshi River Basin

scholarly journals Spatial distribution of soil erosion and sediment yield in the Pra River Basin

2020 ◽  
Vol 2 (3) ◽  
Author(s):  
Ebenezer Boakye ◽  
F. O. K. Anyemedu ◽  
Emmanuel A. Donkor ◽  
Jonathan A. Quaye-Ballard
Keyword(s):  
Spatial Distribution ◽  
Soil Erosion ◽  
River Basin ◽  
Sediment Yield ◽  
Pra River

scholarly journals Assessment of soil erosion and sediment yield using erosion potential method: Case study - Vrbas river basin (B&H)

2018 ◽  
Vol 98 (1) ◽  
pp. 1-14
Author(s):  
Novica Lovric ◽  
Radislav Tosic
Keyword(s):  
Soil Erosion ◽  
River Basin ◽  
Bosnia And Herzegovina ◽  
Sediment Yield ◽  
Soil Management ◽  
Potential Method ◽  
The Past ◽  
Erosion Processes ◽  
Made In

Soil erosion is one of the most significant forms of land degradation in the Bosnia and Herzegovina. The mapping of soil erosion in B&H, as in the study area, was realized 30 years ago (1979-1985). The past decades has been marked by the changes which retained visible tracks and caused numerous changes in the intensity of erosion processes. In this paper, the mapping of the recent state of erosion intensity was performed, and then an analysis of changes was made in relation to the state of 30 years ago. The erosion potential method (EPM) was used for mapping the soil erosion and calculation of gross annual erosion and sediment yield. Erosion Map of the Vrbas river basin was made in the scale of 1:25,000. This Erosion Map counts a total of 69 topographic sections and 4,524 erosion polygons (plots). According to the Erosion Map of the Vrbas river basin, 5,666.88 km2 of the study area is affected by erosion, while 621.71 km2 are accumulating sediments. Annual gross erosion in the Vrbas river basin is 1,223,989.60 m3/year, while sediment yield is 366,088.10 m3/year. These research results are important because this is the first soil erosion map for the Vrbas river basin with EPM methodology for the whole river basin on territory of Bosnia and Herzegovina. The results can be applied in the field of spatial and urban planning, water and soil management on the local and regional level.

Social Forestry in Environmentally Degraded Regions of India: Case-study of the Mayurakshi Basin

1995 ◽  
Vol 22 (1) ◽  
pp. 20-30 ◽  
Author(s):  
Nandini Chatterjee
Keyword(s):  
Soil Erosion ◽  
River Basin ◽  
Forest Products ◽  
River Valley ◽  
Social Forestry ◽  
Fuel Wood

Social Forestry (SF) schemes have been implemented in India since the 1980s to combat deforestation, increase the supply of fuel-wood and fodder, and provide minor forest products for the rural populaton. The relevance of such Schemes in the Mayurakshi River Basin is basically due to its environmentally degraded state. Latterly the Basin has been brought under the Mayurakshi River Valley Project, but unless measures are undertaken to mitigate problems of soil erosion, the efficiency of the Project will be hampered.

scholarly journals Using SWAT to Evaluate Streamflow and Lake Sediment Loading in the Xinjiang River Basin with Limited Data

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 39 ◽  
Author(s):  
Lifeng Yuan ◽  
Kenneth J. Forshay
Keyword(s):  
Soil Erosion ◽  
River Basin ◽  
Lake Sediment ◽  
Sediment Yield ◽  
Sediment Load ◽  
Poyang Lake ◽  
Sediment Source ◽  
Sediment Loading ◽  
Source Areas ◽  
Annual Sediment

Soil erosion and lake sediment loading are primary concerns of watershed managers around the world. In the Xinjiang River Basin of China, severe soil erosion occurs primarily during monsoon periods, resulting in sediment flow into Poyang Lake and subsequently causing lake water quality deterioration. Here, we identified high-risk soil erosion areas and conditions that drive sediment yield in a watershed system with limited available data to guide localized soil erosion control measures intended to support reduced sediment load into Poyang Lake. We used the Soil and Water Assessment Tool (SWAT) model to simulate monthly and annual sediment yield based on a calibrated SWAT streamflow model, identified where sediment originated, and determined what geographic factors drove the loading within the watershed. We applied monthly and daily streamflow discharge (1985–2009) and monthly suspended sediment load data (1985–2001) to Meigang station to conduct parameter sensitivity analysis, calibration, validation, and uncertainty analysis of the model. The coefficient of determination (R2), Nash–Sutcliffe efficiency (NSE), percent bias (PBIAS), and RMSE -observation’s standard deviation ratio (RSR) values of the monthly sediment load were 0.63, 0.62, 3.8%, and 0.61 during calibration, respectively. Spatially, the annual sediment yield rate ranged from 3 ton ha−1year−1 on riparian lowlands of the Xinjiang main channel to 33 ton ha−1year−1 on mountain highlands, with a basin-wide mean of 19 ton ha−1year−1. The study showed that 99.9% of the total land area suffered soil loss (greater than 5 ton ha−1year−1). More sediment originated from the southern mountain highlands than from the northern mountain highlands of the Xinjiang river channel. These results suggest that specific land use types and geographic conditions can be identified as hotspots of sediment source with relatively scarce data; in this case, orchards, barren lands, and mountain highlands with slopes greater than 25° were the primary sediment source areas. This study developed a reliable, physically-based streamflow model and illustrates critical source areas and conditions that influence sediment yield.

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.

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