Phnom Penh (1960s-1990s)/ Hydraulic Infrastructure Development III

Prek Thnot Dam

It has been mentioned previously that the Japanese has been involved in the study of waters around Phnom Penh, and in fact, they have also been one of Cambodia’s donor when it comes to water-related works in the Mekong region. Back in 1968, Japan loaned 1.517 billion yen for the erection of the Prek Thnot Dam, but the project was brought to a halt when security deteriorated in early 1970’s due to Khmer Rouge.

Following the suspension in building the Dam, areas around the construction site has fallen into a state of disrepair. Initial sections of the irrigation systems had also been altered as the site was undertaken by the regime. The Prek Thnot Dam is a dam of 10km primarily intended for flood control and irrigation. During its conception, there were plans to construct a main dam with a principal reservoir, a central hydroelectric station, a secondary diverting dam on the Prek Thnot 12km upstream from the main dam, and an irrigation canal system with a regulating gauge. The project started off to be controversial due to it being a huge structure, and that 15,000 residents would have to relocate for it to be carried out. Irrigation in some areas targeted to benefit from the construction of the dam are also already sufficient, while other areas are using farming methods that depend on rainfall instead of floodwaters.

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Initial plan of the Prek Thnot Project// image courtesy Van Molyvann (2001)

In 1992, an Australian engineering corporation then prepared a report on the present condition of the project that was brought to a stop.  It was found that the embankment of the project was 13% completed, with 4km of irrigation canal and two water outlet gates already constructed by the time work was stopped in 1973. The irrigation tertiary canals were benefiting around 300 hectares of land at that time, and although some initial electrical and mechanical equipment have deteriorated and become unusable, this has called for a reassessment of the possibility to revive the project. With the potential of creating hydroelectric power as a bonus, it was concluded that the project was still beneficial to the area at present if it was to be revived. Only thay modifications were to be made to the original 1960s plan, so that non-coordinated irrigation developments can be solved downstream along Prek Thnot, and environmental degradation in the area that has resulted from the earlier plan could be alleviated if not reversed.

The Australian study suggests strict environmental management policies to be coupled with the return of the Prek Thnot Project, including restocking of fish populations, protection of forests and control of water resources so as to bring the damaged aquatic ecosystem of Prek Thnot back to its state during the early days. In addition, relocation of residents is best addressed through community development projects so the public voices could be heard, as suggested by Van Molyvann. As of 2009, the Cambodian government has been reportted to have planned on picking up the project again.


CAMBODIA. (n.d.). Retrieved December 21, 2015, from

Molyvann, V. (2003). Modern Khmer cities. Phnom Penh, Cambodia: Reyum

Nguyen, T. (1999). The Mekong River and the struggle for Indochina: Water, war, and peace. Westport, Conn.: Praeger.


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