the Khorat Plateau forms the northeastern part of the
country. Its northern and eastern sides drain to the
Mae Kong River. The southern and western borders
are marked by the presence of flattopped peaks (up to
1600 m a.s.l.). The seasonal rainfall cycle is very similar
to that of the North Western Highlands, with a higher
peak in September (9 mm/day) and a totally dry season
between November and February (Fig. 1)