American Journal of Environmental Sciences

An Approach to the Model use for Measuring Suspended Sediment Yield in Ungauged Catchments

Sokchhay Heng and Tadashi Suetsugi

DOI : 10.3844/ajessp.2013.367.376

American Journal of Environmental Sciences

Volume 9, Issue 4

Pages 367-376

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.

Copyright

© 2013 Sokchhay Heng and Tadashi Suetsugi. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.