This study was undertaken to examine the applicability of the SWAT model in Gumera river basin upstream of Lake Tana, Ethiopia for simulating stream runoff and sediment load. The area of river basin was discretized in...This study was undertaken to examine the applicability of the SWAT model in Gumera river basin upstream of Lake Tana, Ethiopia for simulating stream runoff and sediment load. The area of river basin was discretized into 24 sub-catchments using ArcSWAT interface of the model. The semi automated Sequential Uncertainty Fitting (SUFI2) and fully automated Parameter Solution (ParaSol) calibration process built in SWAT calibration and uncertainty program (SWAT-CUP) were used to calibrate the model parameters using time series of flow and sediment load data of 1994 to 2002 and validated with the observed data from years 2003 to 2006. The performance of the model was evaluated using statistical and graphical methods to assess the capability of the model in simulating the runoff and sediment yield for the study area. The coefficient of determination (R2) and NSE values for the daily runoff by using [ParaSol] optimization technique was obtained as 0.72 and 0.71 respectively for the calibration period and 0.79 and 0.78 respectively for the validation period, R2 and NSE values of monthly flow calibration using SUFI2 are 0.83 and 0.78 respectively for validation it was 0.93 and 0.93. For monthly sediment yield by using SUFI2 calibration technique the model evaluation coefficients R2 and NS for calibration was computed as 0.61 and 0.60 respectively, for validation it was 0.84 and 0.83 respectively. The sensitivity analysis on 13 runoff producing parameters was also carried out and discussed.展开更多
Sustainable management of Ivory Coast’s freshwater reserve at a catchment scale is an essential way in the policies of land use sustainable management. Thus, the implementation of physical conceptual semi-distributed...Sustainable management of Ivory Coast’s freshwater reserve at a catchment scale is an essential way in the policies of land use sustainable management. Thus, the implementation of physical conceptual semi-distributed SWAT model required a good knowledge of the watershed and a large number of physic-chemical data available that have been prior adapted to Ivory Coast’s climatic and soil conditions. The whole simulation span was divided into calibration set (1982-1986) and validation set (1987-1990). The SUFI-2 algorithm was used for parameters optimization. The sensitivity analysis focused on 8 parameters related to runoff, soil, evaporation, main channel and groundwater. The performance criteria were based on the P-factor, R-factor and the two objective functions which are Nash-Sutcliffe coefficient and the coefficient of determination. Although Taabo river basin like African basins suffers from a significant lack of data, the objective functions showed the robustness of the model to climate variability. The calibration launched during a wet period gave objective functions higher than 0.7 while validation performed in less humid period gave performance criteria around 0.6. During the simulation period, Taabo river basin daily green water ranged from 0.044 to 50.257 mm/day with a total average of 3,090.9 mm per year. As for blue water, it is ranged from 0.032 to 0.552 mm/day with an annual total average of 29.19 mm.展开更多
Effective management of water resources in West African basins is increasingly hindered by sparse hydrometeorological datasets,high interannual rainfall var-iability,and nonlinear feedbacks among climate,land use,and ...Effective management of water resources in West African basins is increasingly hindered by sparse hydrometeorological datasets,high interannual rainfall var-iability,and nonlinear feedbacks among climate,land use,and hydrological processes.To address these constraints,this study implemented the Soil and Water Assessment Tool(SWAT)in conjunction with the SUFI-2(Sequential Uncertainty Fitting v2)algorithm in the Thiokoye River Basin—an understud-ied sub-catchment of the Gambia River situated at the interface of Southern Sudanian and Guinean climatic zones.The model was calibrated(1979-1992)and validated(1998-2002)using multiple performance metrics(NSE,R^(2),KGE,PBIAS)and uncertainty indicators(p-factor,r-factor).Calibration yielded ex-cellent results(NSE=0.98,R^(2)=0.98,p-factor=0.90),with similarly robust validation scores(NSE=0.82,R^(2)=0.83,KGE=0.81,PBIAS=–13.2%).Hy-drological simulations showed strong seasonal partitioning,with blue water fluxes—surface runoff,percolation,and water yield—constrained to the May-October wet season,representing only 22%of annual rainfall.Conversely,green water availability remained low year-round(mean ET/PET=0.19),sug-gesting persistent vegetative water stress.Sediment modeling indicated acute erosion risk,with over 96%of annual soil loss(15.5 t/ha)occurring during peak rainfall periods.Sensitivity analysis revealed CN2,ALPHA_BF,GW_DELAY,and CH_K2 as dominant controls on runoff and groundwater dynamics.These results underscore the utility of the SWAT-SUFI-2 framework for simulating hydrological and sediment processes in data-limited tropical basins and in-forming targeted strategies for watershed management and climate resilience.展开更多
文摘This study was undertaken to examine the applicability of the SWAT model in Gumera river basin upstream of Lake Tana, Ethiopia for simulating stream runoff and sediment load. The area of river basin was discretized into 24 sub-catchments using ArcSWAT interface of the model. The semi automated Sequential Uncertainty Fitting (SUFI2) and fully automated Parameter Solution (ParaSol) calibration process built in SWAT calibration and uncertainty program (SWAT-CUP) were used to calibrate the model parameters using time series of flow and sediment load data of 1994 to 2002 and validated with the observed data from years 2003 to 2006. The performance of the model was evaluated using statistical and graphical methods to assess the capability of the model in simulating the runoff and sediment yield for the study area. The coefficient of determination (R2) and NSE values for the daily runoff by using [ParaSol] optimization technique was obtained as 0.72 and 0.71 respectively for the calibration period and 0.79 and 0.78 respectively for the validation period, R2 and NSE values of monthly flow calibration using SUFI2 are 0.83 and 0.78 respectively for validation it was 0.93 and 0.93. For monthly sediment yield by using SUFI2 calibration technique the model evaluation coefficients R2 and NS for calibration was computed as 0.61 and 0.60 respectively, for validation it was 0.84 and 0.83 respectively. The sensitivity analysis on 13 runoff producing parameters was also carried out and discussed.
文摘Sustainable management of Ivory Coast’s freshwater reserve at a catchment scale is an essential way in the policies of land use sustainable management. Thus, the implementation of physical conceptual semi-distributed SWAT model required a good knowledge of the watershed and a large number of physic-chemical data available that have been prior adapted to Ivory Coast’s climatic and soil conditions. The whole simulation span was divided into calibration set (1982-1986) and validation set (1987-1990). The SUFI-2 algorithm was used for parameters optimization. The sensitivity analysis focused on 8 parameters related to runoff, soil, evaporation, main channel and groundwater. The performance criteria were based on the P-factor, R-factor and the two objective functions which are Nash-Sutcliffe coefficient and the coefficient of determination. Although Taabo river basin like African basins suffers from a significant lack of data, the objective functions showed the robustness of the model to climate variability. The calibration launched during a wet period gave objective functions higher than 0.7 while validation performed in less humid period gave performance criteria around 0.6. During the simulation period, Taabo river basin daily green water ranged from 0.044 to 50.257 mm/day with a total average of 3,090.9 mm per year. As for blue water, it is ranged from 0.032 to 0.552 mm/day with an annual total average of 29.19 mm.
文摘Effective management of water resources in West African basins is increasingly hindered by sparse hydrometeorological datasets,high interannual rainfall var-iability,and nonlinear feedbacks among climate,land use,and hydrological processes.To address these constraints,this study implemented the Soil and Water Assessment Tool(SWAT)in conjunction with the SUFI-2(Sequential Uncertainty Fitting v2)algorithm in the Thiokoye River Basin—an understud-ied sub-catchment of the Gambia River situated at the interface of Southern Sudanian and Guinean climatic zones.The model was calibrated(1979-1992)and validated(1998-2002)using multiple performance metrics(NSE,R^(2),KGE,PBIAS)and uncertainty indicators(p-factor,r-factor).Calibration yielded ex-cellent results(NSE=0.98,R^(2)=0.98,p-factor=0.90),with similarly robust validation scores(NSE=0.82,R^(2)=0.83,KGE=0.81,PBIAS=–13.2%).Hy-drological simulations showed strong seasonal partitioning,with blue water fluxes—surface runoff,percolation,and water yield—constrained to the May-October wet season,representing only 22%of annual rainfall.Conversely,green water availability remained low year-round(mean ET/PET=0.19),sug-gesting persistent vegetative water stress.Sediment modeling indicated acute erosion risk,with over 96%of annual soil loss(15.5 t/ha)occurring during peak rainfall periods.Sensitivity analysis revealed CN2,ALPHA_BF,GW_DELAY,and CH_K2 as dominant controls on runoff and groundwater dynamics.These results underscore the utility of the SWAT-SUFI-2 framework for simulating hydrological and sediment processes in data-limited tropical basins and in-forming targeted strategies for watershed management and climate resilience.
