Spatial Interpolation in Water Runoff : Hydrology in Vietnam, Laos and Cambodia

Abstract

This thesis project was conducted on historical hydrological data. This thesis focuses on the water movement in the 3S basin. The 3S river basin is a transboundary river basin, contributing considerably to the geographical and economical activities for three countries, Cambodia, Lao PDR, and Vietnam. The main three rivers are Sekong, Sre Pok and Sesan, which affect the lots of surrounding livelihoods. The purpose was to use low-resolution runoff and observed streamflow data to determine a prediction of runoff in high resolution raster image with low-resolution runoff data and to compare high-resolution results with the standard error value obtained with the help of streamflow measurement. This thesis presents different interpolation techniques and error methods. The presentation covers the method of inverse distance weighing, ordinary kriging, and topological kriging interpolation, providing a sound knowledge of how each of the methods works. The required procedure for the spatial data analysis was performed using R-studio and QGIS. Results obtained show, less error for high-resolution than standard low-resolution data. Among error propagation used, KGE value is mostly considered for a proper representation of the goodness of fit. On further analyzing, absolute difference, least-square difference, and ANOVA process were performed on the obtained error value. This suggests that the error value had no relation with each other according to the station while there was no significant difference between the method used. Finally, the absolute difference and least square difference between standard and methods, revealed that TK had the least deviation from standard than of other methods.