Introduction
The northeast region of Thailand, an area of
approximately 170,000 km2, supports about 22
million people. There are three main basins including
Mekong, Chi, and Mun River Basin. The total water
storage in the region is about 5,300 million m3. An
analysis from the National Water Resources Development Project, Royal Irrigation Department in 1993
found that the water demand in this region was about
10,800 million m3 and will be 14,300 million m3
in 2006 [6]. Several surface water reservoirs and weirs
have been constructed over the existing rivers. The
use of some surface water systems was limited due to
poor yield and quality [2]. Agriculture is the main
occupation in northeast of Thailand. Common crops
in this region are cassava, sugar cane, corn, kenaf