Characterization and Delineation of Types of Drought in the Northeast of Thailand for Rice Production through Water Balance Modeling-GIS

Abstract

The study was made to quantify the frequency and severity of drought in the area, in order to generate the surface water as an indicator of drought prone in the Northeast (NE) of Thailand. Using weekly long-term records of meteorological data (1987-2003) and soil characteristics, which are erratic distribution and variable by time and spatial. The water balance modeling was created in the Visual Basic Application software integrated with GIS to analyze a large quantity of such data pertaining to the rice-growing seasons. Surface water was simulated by focusing on the early, mid and late rainy seasons according to phynology of rice. In this way, a prediction of the amount of water for rice production in the different areas in weekly surface water was conveniently interpreted. The simulated result was shown that, the upper NE especially in the Nong Khai and Nakhon Phanom Provinces corner had sufficient surface water throughout the rice growing seasons however, late season drought may occurred. Conversely, sufficient surface water were found during the end of the rice growing seasons in the lower NE such as Nakhon Ratchasima province like wise, drought occurrence may also found since the very beginning and middle of the rice growing seasons.