The Chao Phraya River Basin, which covers 163,000 km², is the most important basin in Thailand. The Basin covers 30% of the land area and is home to about 42% of the total population of the country. The flood damage potential in the Basin is increasing due to a rapid urbanization and land development in the deltaic areas, specially in the capital of Thailand, Bangkok.In October of 1995 a disastrous flood occurred, resulting in a loss of many human lives and property damage in an extensive area.

The master plan for integrated flood damage mitigation in the Chao Phraya River Basin was formulated in accordance with the His majesty concept of "Monkey Cheek" (basically consist in storing the flood water to use it in the dry season), along with the introduction of suitable flood mitigation measures, through river improvement, construction of a diversion channel, conservation of natural retarding effects, etc., and non-structural measures including land use control and guidance.