scholarly journals Assessment of Hydrology and Sediment Yield in the Mekong River Basin Using SWAT Model

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3503
Author(s):  
Ty Sok ◽  
Chantha Oeurng ◽  
Ilan Ich ◽  
Sabine Sauvage ◽  
José Miguel Sánchez-Pérez
Keyword(s):  
Soil Erosion ◽  
River Basin ◽  
Sediment Yield ◽  
Large Scale ◽  
Sediment Load ◽  
Swat Model ◽  
Mekong River ◽  
Scale Model ◽  
Time Step ◽  
Mekong River Basin

The Mekong River Basin (MRB) in Southeast Asia is among the world’s ten largest rivers, both in terms of its discharge and sediment load. The spatial and temporal resolution to accurately determine the sediment load/yield from tributaries and sub-basin that enters the Mekong mainstream still lacks from the large-scale model. In this study, the SWAT model was applied to the MRB to assess long-term basin hydrology and to quantify the sediment load and spatial sediment yield in the MRB. The model was calibrated and validated (1985–2016) at a monthly time step. The overall proportions of streamflow in the Mekong River were 34% from surface runoff, 21% from lateral flow, 45% from groundwater contribution. The average annual sediments yield presented 1295 t/km2/year in the upper part of the basin, 218 t/km2/year in the middle, 78 t/km2/year in the intensive agricultural area and 138 t/km2/year in the highland area in the lower part. The annual average sediment yield for the Mekong River was 310 t/km2/year from upper 80% of the total MRB before entering the delta. The derived sediment yield and a spatial soil erosion map can explicitly illustrate the identification and prioritization of the critical soil erosion-prone areas of the MR sub-basins.

scholarly journals Water Resources Observation and Large-scale Model Estimation in Forested Areas in Mekong River Basin

2010 ◽  
Vol 44 (2) ◽  
pp. 179-186 ◽  
Author(s):  
Akira SHIMIZU ◽  
Masakazu SUZUKI ◽  
Shinji SAWANO ◽  
Naoki KABEYA ◽  
Tatsuhiko NOBUHIRO ◽  
...  
Keyword(s):  
Water Resources ◽  
River Basin ◽  
Large Scale ◽  
Mekong River ◽  
Scale Model ◽  
Model Estimation ◽  
Mekong River Basin ◽  
Large Scale Model ◽  
Forested Areas

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.

scholarly journals Assessing the large-scale impacts of environmental change using a coupled hydrology and soil erosion model

2018 ◽  
Vol 6 (3) ◽  
pp. 687-703 ◽  
Author(s):  
Joris P. C. Eekhout ◽  
Wilco Terink ◽  
Joris de Vente
Keyword(s):  
Soil Erosion ◽  
Environmental Change ◽  
Sediment Yield ◽  
Large Scale ◽  
Catchment Scale ◽  
Time Step ◽  
Vegetation Development ◽  
Erosion Model ◽  
Complete Representation ◽  
Large Catchment

Abstract. Assessing the impacts of environmental change on soil erosion and sediment yield at the large catchment scale remains one of the main challenges in soil erosion modelling studies. Here, we present a process-based soil erosion model, based on the integration of the Morgan–Morgan–Finney erosion model in a daily based hydrological model. The model overcomes many of the limitations of previous large-scale soil erosion models, as it includes a more complete representation of crucial processes like surface runoff generation, dynamic vegetation development, and sediment deposition, and runs at the catchment scale with a daily time step. This makes the model especially suited for the evaluation of the impacts of environmental change on soil erosion and sediment yield at regional scales and over decadal periods. The model was successfully applied in a large catchment in southeastern Spain. We demonstrate the model's capacity to perform impact assessments of environmental change scenarios, specifically simulating the scenario impacts of intra- and inter-annual variations in climate, land management, and vegetation development on soil erosion and sediment yield.

Responses of river discharge and sediment load to climate change in the transboundary Mekong River Basin

2019 ◽  
Vol 34 (S1) ◽  
pp. 367-380
Author(s):  
Dao Nguyen Khoi ◽  
Van Thinh Nguyen ◽  
Truong Thao Sam ◽  
Nguyen Ky Phung ◽  
Nguyen Thi Bay
Keyword(s):  
Climate Change ◽  
River Basin ◽  
River Discharge ◽  
Sediment Load ◽  
Mekong River ◽  
Mekong River Basin

Inundation Process in the Lower Mekong River Basin

2016 ◽  
Vol 11 (6) ◽  
pp. 1062-1072 ◽  
Author(s):  
Shun Kudo ◽  
◽  
Atsuhiro Yorozuya ◽  
Hiroshi Koseki ◽  
Yoichi Iwami ◽  
...  
Keyword(s):  
Shear Stress ◽  
Hydraulic Resistance ◽  
River Basin ◽  
Water Depth ◽  
Large Scale ◽  
River Channel ◽  
Mekong River ◽  
Mekong River Basin ◽  
Inundation Simulation ◽  
Inundation Extent

This study simulated the inundation process in the Lower Mekong River Basin (LMB). The LMB has suffered from severe floods, especially in 2000 and 2011. To quantify the inundation of water in a basin where large-scale inundation by river water occurs, understanding the conveyance of a river channel during a flood is particularly important. Therefore, we conducted a field survey using an acoustic Doppler current profiler (aDcp) to understand the longitudinal distribution of the width and depth of the river channel and the variation in hydraulic resistance with respect to shear stress on the riverbed. It was found that the width and depth vary longitudinally, and the relationship between them can be estimated by an equation derived from governing equations of water and sediment and the bed load formula. Furthermore, it was revealed that hydraulic resistance decreases with increasing non-dimensional shear stress. Then, the characteristics of the river channel were incorporated into the runoff-inundation simulation. Furthermore, inundation water should be validated not only in terms of inundation extent but also with respect to water depth and velocity. These were estimated using 8-day composite surface reflectance data from the Moderate Resolution Imaging Spectrometer (MODIS) and the SRTM. Simulation results indicated that water level and discharge within the river channel were able to reproduce observed values. Additionally, simulated inundation extent, water velocity, and water depth over the floodplain showed reasonable agreement with the results using the data from the MODIS and the SRTM. Although there are some elements that should be improved, the inundation process in the LMB was simulated appropriately despite its complexity. The method described in this study to set a calculation condition and to validate variables over a floodplain should be useful for runoff-inundation simulation in various large-scale basins.

scholarly journals Assessing the large-scale impacts of environmental change using a coupled hydrology and soil erosion model

2018 ◽  
Author(s):  
Joris P. C. Eekhout ◽  
Wilco Terink ◽  
Joris de Vente
Keyword(s):  
Soil Erosion ◽  
Environmental Change ◽  
Sediment Yield ◽  
Large Scale ◽  
Spatial Scales ◽  
Catchment Scale ◽  
Time Step ◽  
Vegetation Development ◽  
Erosion Model ◽  
Large Catchment

Abstract. Assessing the impacts of environmental change on soil erosion and sediment yield at the large catchment scale remains one of the main challenges in soil erosion modelling studies. Here, we present a process-based soil erosion model, based on the integration of the Morgan-Morgan-Finney erosion model in a daily-based hydrological model. The model overcomes many of the limitations of previous large-scale soil erosion models, as it includes a more complete representation of crucial processes like surface runoff generation, dynamic vegetation development, and sediment deposition, and runs at the catchment scale with a daily time step. This makes the model especially suited for evaluation of the impacts of environmental change on soil erosion and sediment yield at large spatial scales. The model was successfully applied in a large catchment in southeastern Spain. We demonstrate the models capacity to perform impact assessments of environmental change scenarios, specifically simulating the scenario impacts of intra- and inter-annual variations in climate, land management and vegetation development on soil erosion and sediment yield.

scholarly journals Evaluation of Grid-Based Rainfall Products and Water Balances over the Mekong River Basin

2020 ◽  
Vol 12 (11) ◽  
pp. 1858
Author(s):  
Kha Dang Dinh ◽  
Tran Ngoc Anh ◽  
Nhu Y Nguyen ◽  
Du Duong Bui ◽  
Raghavan Srinivasan
Keyword(s):  
River Basin ◽  
Land Surface ◽  
Swat Model ◽  
Climate Prediction ◽  
Mekong River ◽  
Mekong River Basin ◽  
Spatial Coverage ◽  
Daily Scale ◽  
Climate Prediction Center ◽  
Hydrological Applications

Gridded precipitation products (GPPs) with wide spatial coverage and easy accessibility are well recognized as a supplement to ground-based observations for various hydrological applications. The error properties of satellite rainfall products vary as a function of rainfall intensity, climate region, altitude, and land surface conditions—all factors that must be addressed prior to any application. Therefore, this study aims to evaluate four commonly used GPPs: the Climate Prediction Center (CPC) Unified Gauge-Based Analysis of Global Daily Precipitation, the Climate Prediction Center Morphing (CMORPH) technique, the Tropical Rainfall Measuring Mission (TRMM) 3B42, and the Global Satellite Mapping of Precipitation (GSMaP), using data collected in the period 1998–2006 at different spatial and temporal scales. Furthermore, this study investigates the hydrological performance of these products against the 175 rain gauges placed across the whole Mekong River Basin (MRB) using a set of statistical indicators, along with the Soil and Water Assessment Tool (SWAT) model. The results from the analysis indicate that TRMM has the best performance at the annual, seasonal, and monthly scales, but at the daily scale, CPC and GSMaP are revealed to be the more accurate option for the Upper MRB. The hydrological evaluation results at the daily scale further suggest that the TRMM is the more accurate option for hydrological performance in the Lower MRB, and CPC shows the best performance in the Upper MRB. Our study is the first attempt to use distinct suggested GPPs for each individual sub-region to evaluate the water balance components in order to provide better references for the assessment and management of basin water resources in data-scarce regions, suggesting strong capabilities for utilizing publicly available GPPs in hydrological applications.

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