Abstract
Different types of water resources studies require the information of Suspended Sediment Yield (SSY) in different time resolutions. In ungauged watersheds where hydrometeorogical time series are not available, the mean annual SSY (SSYa) is solely predictable and catchment area is traditionally used as the predictor because it is the most important variable and generally determined during project planning. Firstly, this research tried to advance the traditional SSYa model by additionally associating global topographic data. Based on the jack-knife procedure, the modified method considering catchment area with slope greater than 15% was evaluated in 17 gauged catchments in the Lower Mekong Basin and the overall predictive accuracy was improved about 66% in term of mean absolute percentage error. Secondly, the predicted SSYa in each modeled catchment was monthly distributed using Unit mean annual Sedimentograph (USGa). The double-average USGa superior to the single-average one provides overall better quality results than the regionalized USGa dependent upon the spatial proximity approach. The model performance measured by Nash-Sutcliffe Efficiency (NSE) is about 0.66 in median value and satisfactory results (NSE >0.50) are obtained in 11 catchments. Lastly, the validated regional model was regarded as a potential and feasible tool in solving sediment-ungauged issues in the basin.
Highlights
15% was evaluated in 17 gauged catchments in the Lower Mekong Basin and the overall predictive accuracy was improved about 66% in term of mean absolute percentage error
Sediment yield is the amount of sediment discharged by a catchment over a period of time
Another empirical approach associating catchment Area (A0) as a predictor is often in use. This technique enables solely the point value prediction such as mean annual Suspended Sediment Yield (SSY) (SSYa), it is surely feasible because A0, the most important variable, is generally determined during project planning (Tamene et al, 2006)
Summary
Sediment yield is the amount of sediment discharged by a catchment over a period of time In alluvial rivers, it often depends on suspended load which is the predominant portion and commonly accounts for more or less 90% (Walling and Fang, 2003; Francke et al, 2008; Zhang et al, 2012). (2012); Cibin et al (2013) and Seibert and McDonnell (2013) In this regard, another empirical approach associating catchment Area (A0) as a predictor is often in use. Another empirical approach associating catchment Area (A0) as a predictor is often in use This technique enables solely the point value prediction such as mean annual SSY (SSYa), it is surely feasible because A0, the most important variable, is generally determined during project planning (Tamene et al, 2006). Applications of the A0-SSYa relationship can be found in various existing studies, e.g., Verstraeten et al
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