Study of Relationship between Physical Characteristic and Hydrological Characteristic of Basin : Case Study in North Basin in Thailand, 1996

Suathae, Chalermchai; Pornsathap, Somwang and Saelee, Surachan

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

Abstract

Lacking of hydrological data both in quality and quantity causes a problem of insufficient data for hydrological analysis of a basin leading to inadequate information for water resources development and planing. Particularly, the insufficient streamflow gauging station result in the difficulties in determination of runoff of a basin. The study aims to alleviate such problem by investigation of the relationship between annual runoff and its physical characteristics in order to use such characteristics to estimate the volume of annual runoff a basin where there does not exist any streamflow gauging stations. Land use, soil type, and rock type were selected to defined physical characteristics of basin. There information were extracted from existing maps of the study area located in the northern region of Thailand , covering a total drainage area of 13,130 km. with 17 subbasins of size from 35 km. to 2795 km. The estimation of runoff coefficients of each type of physical characteristics was manipulated on by one independently by using optimization technique of system of linear equations under physical meaning. Comparison between observed runoff and computed runoff indicates that these coefficients can be used to estimate annual runoff on this region with quite satisfactory results. The proposed methedology and the result a obtained can be applied to estimate annual runoff for ungaged basin which are frequently located in remote area and water resources development is required, particularly in the northern region of Thailand whose physical characteristics are similar to the study area.