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Basic information about Rasi Salai dam


  • South-East Asia Rivers Network (SEARIN Thailand)
  • The Committee to Save Tam Mun (The Committee to Save the Fresh Water Swamp Forest in the Mun River)
  • Assembly of the Poor
  • Wildlife Fund Thailand

April 20,1999

Rasi Salai Dam is located in the middle part of the Mun River, the largest tributary of the Mekong. Construction commenced in 1992 by Department of Power Development and Promotion (DPDP), Ministry of Sciences, Technology, and Environment. This dam is a part of Kong-Chi-Mun Water Diversion Project, the largest water diversion project in Northeastern Thailand. Under this project, DPDP has plans to build 13 dams on the Chi and Mun rivers within 42 years, at a total cost of $US5.7 billion. This water diversion project was promoted by the DPDP and politicians during the late 1980s. They claimed the project will solve the water shortages in Northeast Thailand by divert water from Mekong River to the Chi and Mun Rivers.

The process of construction was very deceitful. DPDP began construction secretively, did not release any information to the public, and stated they would only build a small rubber weir, not a concrete dam. At Rasi Salai, the government approved it as a rubber weir 4.5 meters high, and stated that the water level would not rise above the river bank. In fact, the DPDP built a 9 meter high concrete dam. This deception took place in every dam in Kong-Chi-Mun Project.

Rasi Salai dam is a large-scale dam because more than 100 square kilometers were inundated (80 sq. km. of farmland and fresh water swamp forest). Under the Environmental Act, every dam project which has a reservoir of 15 square kilometers or more must have an EIA. However, the DPDP failed to conduct an EIA at Rasi Salai. Therefore, Rasi Salai dam is an illegal dam and DPDP have broken the law, even though DPDP is under the Ministry of Sciences Technology and Environment, who are responsible for the Environmental Act.

This poor process has lead to many problems as following:

1.Economic Impacts:

1.1 A construction cost overrun of more 622 per cent. The original cost was estimated to be 140 million Baht, but the real construction cost was 871 million Baht.

1.2 The dam was promised to irrigate 55.072 sq. km. If we calculate by the existing modern irrigation system in the North-East, which has only 37% efficiency, this dam will provide irrigation to only 20.37 sq. km. while it flooded about 80 sq. km of fertile land. Even though the dam was completed in 1994, the irrigation system is not operational.

2.Environmental Impacts:

2.1 The dam destroyed the fresh water swamp forest along the banks of the Mun River. This ecosystem is very important. In ecological terms, it is a habitat for fish, provides food for fish, and an area for fish breeding. The fresh water swamp forest along the banks of the Mun River is also useful for flood control, treating toxic water, and has very high biodiversity value. In social terms, it provided food, herbal medicine, as well as farmland for villagers.

2.2.The dam blocks the migration of fish in the middle reaches of the Mun River. Fish is very important for local villagers.

2.3 The reservoir has been plagued by salination problems, because it is on top of a big salt dome. Two years after the dam was completed, the Department of Land Development found high salinity content in the reservoir because the water in the reservoir dissolves the salt underground and there is no natural drainage of water. Officials from the Department of Interior confirmed this problem.

3. Social Impacts:

More than 3000 families lost their farmland by the reservoir. Although they were against large dams, DPDP deceived them by stating that they would built a rubber weir, so the villagers did not oppose the project. After villagers discovered the facts, they started to demonstrate. However DPDP did not pay compensation to them because there was no EIA report and no field surveys, so there is no baseline data about the affected people. After the demonstration PBB paid for private property only, and gave no compensation for common lands.

Moreover, DPP constructed a dyke to reduce the number of affected villagers (DPDP has plan to construct a 45.8 km long dike). However, the dyke has created worse impacts. Its does not allow the water to flow into the reservoir in monsoon season, and so it floods a vast area of farmland. DPP established some flood-gates with check valves along the dyke, but it has been ineffective. Moreover, some time the water flows backwards from the reservoir, because of poor maintenance.

After a long struggle, Gen. Chawalit Yongjaiyut's Government paid compensation to 1154 villager families out of more than 3000 affected families.

Gen.Chawalit's Government agreed to correct the problems caused by dyke construction by installing more mega-pumps for draining water to the reservoir, and to maintain the flood gates, but DPDP did nothing.

4.Human Rights Impact:

To construct the dam, the Government and DPP were not concerned about human rights, and violated the constitution. They did this by supporting other groups to attack the affected peoples, and by arresting village leaders. On January 18th of this year, 4 village leaders were arrested by police. They are Ms. Pha Kongkaew, Mr. Saksit Buapan, Mr. Pijit Silalak, and Mr. Boonmee Sopang. And on April 18th , Mr. Boon Nanaul was arrested. Now most of them are facing court proceedings.


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