The Delineation of Drought Areas in Nakhon Ratchasima Province, Thailand

摘要

Droughts are natural disasters and they have resulted in Thailand being ranked among the world's most vulnerable countries. Climate change has increased the tendency and frequency of this type of disaster, affecting crop production and the way that farmers live in the Thai society. Nakhon Ratchasima Province was selected as the area for the present study, and it is located in the northeastern part of Thailand, consisting of 32 districts covering the area of 2,072,840.66 ha. It is the country's largest province by area and has the second largest population in Thailand. The objectives of the research were to develop a drought model and to develop a drought risk map for this province for disaster management. The Universal transverse Mercator (UTM) system was used as a standard coordinate system in this study. The raster data model of selected parameters was used. Further the GRID module and Map Algebra of the Geographic Information System (GIS) were employed. Four parameters were used-slope, soil drainage, land use, and water sources-for the analysis. The results showed five levels of drought risk, classified as having very low risk, low risk, medium risk, high risk, and very high risk. The high risk drought areas were the highest areas in the province (885,612.08 ha or 42.72 %), followed by medium risk (418,406.90 ha or 20.19%), low risk, (189,840.79 ha or 9.16%), very high risk (74,982.73 ha or 3.62 %), and very low risk areas (12,863.55 ha or 0.62 %). One thousand five hundred and two villages have been affected by drought at the levels of very high risk, high risk, and medium risk. In addition, 337 villages have been affected by drought at the levels of very low risk and low risk. Moreover, the village locations subject to different risks were disseminated as the layer that was used with Google Earth software for drought management. The results of this research can be used as baseline information for drought prevention and drought management and planning.