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, especially in Bangkok, the capital of Thailand. In October of 1995, a disastrous flood occurred with a result of extensive damage to the property and loss of many human lives.

The master plan for integrated flood damage mitigation in the Chao Phraya River Basin was formulated in accordance with the "Monkey Cheek" concept for preservation of the present retarding effect, along with the introduction of suitable flood mitigation measures.

The plan consists of structural measures including river improvement, construction of a diversion channel, conservation of natural retarding effects, and non-structural measures including land use control and guidance, and effective operation of dam reservoirs.