Estimation of Runoff for Ungaged Basin Using Basin Physical Characteristics Derived from Satellite Imagary, 1996

Abstract

One of the problems in water resources development in Thailand is lack of hydrological data both in quality and quantity. The insufficient streamflow gauging station over Thailand making the determination of runoff of a basin rather difficult.

This study aims to investigate relationship between annual runoff of basin and its physical characteristic in order to use that physical parameters to estimate the volume of annual runoff of an ungauged basin. Land use, geology and soil type of basin are selected as physical characteristic of the basin in the study. The relationships between these characteristics and annual rainfall and runoff established one by one independently using a simple statistical analysis. These relationships were calibrated and test on five basins of the study area located in the South of Thailand ( Klong Utaphao River Basin, Songkhala Province)

The results of the study reveal that the physical characteristics of basin can be used to estimate annual runoff with quit satisfactory accuracy, and that either of selected physical characteristic (i.e. land use, geology or soil type) can be used to estimate runoff with the same level of accuracy. This approach can therefore be applied to estimate the annual runoff of the remote ungauged basin where water resources development and planning are required.