Use Of Satellite Imagery In Estimation Of Runoff For Water Resources Development, 1995

Sirijanthakul, Somboon and Supanpong, Atthapon

Major Field of Civil Engineering, Faculty of Engineering, Thammasart University (The Rangsit Center) Pathumthani 12121, Thailand

Abstract

One of problem in water resources development in Thailand is lack of hydrological data both in quality and quantity. The insufficient streamflow gaging stations over Thailand making the determination of runoff of a wartershed is rather difficult.

This study aims to investigate relationship between annual runoff of watershed and its physical characteristic in order to use the physical parameters to estimate the volume of annual runoff of an ungaged watershed. Lade use, geology and soil type of watershed are selected as physical characteristic of watershed in the study. The relationships between these characteristic annual rainfall and runoff were established one by one independently using a simple statistical analysis. These relationships were calibrated and tested on five watershed of the study area located in the South of Thailand (Klong U-Taphao River, Songkhls Province).

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