Nam Ngum Dam

The dam was constructed in three stages, beginning in with stage I in 1968 and ending with the completion of stage III in 1984. The Mekong River Commission first implemented the dam project as part of the national development plan. The project was mainly focused on harnessing Lao PDR's hydropower potential, but it has also striven to achieve flood protection, implement lift irrigation, facilitate lake fisheries, and develop Lao PDR's tourism industry. The Nam Ngum Dam has a capacity of 155 MW and generates most of Laos' electricity, including all the power used in the capital, Vientiane. Additionally 70–80 percent of electricity created by the dam is exported to Thailand. The revenue from export accounts for about a quarter of Laos' foreign exchange earnings. The gross power revenues of the dam are approximately US$36 million annually. Recent studies have indicated that the dam has adversely affected lake fishery and the Nam Ngum River ecosystem. Responsibility for operation of the project rests with the national power utility Electricité du Laos, a state enterprise under the Ministry of Industry and Handicraft.[1]

Today, the Lao PDR's hydropower potential is widely recognized as one of the country's main resources, since it enjoys a strategic location between the booming economies of China, Vietnam, and Thailand and rivers that contribute 35 percent of Mekong flows. The Lao PDR has an estimated potential of some 18,000 MW from over 60 project sites on the tributaries of the Mekong River, of which less than 3 percent has been developed.[2]

The Nam Ngum River originates in Phou Kout in the northeastern part of the Tran Ninh Plateau, through which the river flows southwestward, and discharges into the Mekong River 55 kilometers east of Vientiane. Covering seven percent of the nation's land area, the Nam Ngum basin is home to roughly 500,000 people, representing approximately nine percent of the Lao PDR's population. The length of the river is 420 kilometers. The Nam Ngum project is 60 kilometers north of Vientiane on the Nam Ngum tributary of the Mekong, within the Vientiane Capital Province.[2] The Nam Ngum catchment covers 8,460 km² (3,266 sq mi), and is on track to becoming one of the most heavily dammed catchments in Laos, with six additional dams at various stages of planning and construction, and two water diversions.[2]

Laos

During the 1960s, power production in the Kingdom of Laos was not sufficient to meet national needs. The government had attempted to meet power requirements through small local developments and power loans from Thailand. A feasibility study presented in December 1962 was the first detailed plan outlining the Nam Ngum 1 project. The study explained how the proposed dam could contribute to hydropower generation, flood control, and irrigation. The project was well received by the Lao government and many international organizations, and the plan for construction was finalized in 1968.[1] Three distinct feasibility studies were conducted to outline each stage of the project, and three distinct funds were established to fund all three stages of the Nam Ngum 1 project. Ten countries gave financial aid to pay for its construction.[3] These funds were collected, overseen, and administered by the United Nations and The World Bank. The total cost of the Nam Ngum Dam was US$97 million.[1]

As rapid economic development continues in Southeast Asia and the lower Mekong basin, demands for both food and energy will continue to rise. The Lao government is also keen to utilize its water resources to pursue irrigation expansion and more hydropower projects. This development is seen as critically important for meeting current and future energy demand in the rapidly growing cities and towns throughout the lower Mekong in Thailand, Vietnam, and Laos. With these rising demands come the challenges of regional management of water resources and increased pressure upon surrounding ecosystems. Within this context, the implications of the Nam Ngam Dam, and other projects like it, are a matter of some controversy. Whether or not hydropower-based economic development is consistent with other socioeconomic and environmental objectives in the Lao PDR (irrigation, fisheries, flood control) has scarcely been explored.[2]

Determining the viability of the dual strategy of irrigation and hydropower expansion requires careful analysis to understand whether the water needed for energy generation objectives could be balanced with the water that would be required for additional irrigation development. The issue is that the dam projects in the Nam Ngum are often independently planned and managed, with only minimal consideration of their cumulative and basin-wide economic and hydrological impacts. The lack of coordination is evident in recent controversies and observed flood damages from poorly managed water releases during high flow events. This is in part due to an insufficient valuation of the country's vast water resources. Revenues from electricity generation at individual dams sometimes overshadow potential trade-offs with other important economic sectors like agriculture and aquaculture, or with the nonmarket value generated by subsistence fisheries and other hydrological services.[2]

Fishing in particular is extremely important to the local economy. Fishing provides the primary source of meat for these villagers, with fish contributing 56.3 percent of protein to the local diet. The average household consumes 83.2 kg fish protein each year compared to the Laos national average of 8–10 kg /year. Among these households, 50 percent supplement family income by selling fish to traders in their villages. In total villagers harvest more than 55 indigenous species from in the Nam Ngum reservoir annually. In recent years the excess harvesting of the Nam Ngum reservoir has greatly reduced the biodiversity of the reservoir, and made fishing more difficult. Many ecologists have criticized the Lao PDR for failing to effectively manage reservoir fishing. Annual fish production in the reservoir from 1979 to 1983 was estimated at 1,472 tons or 37 kg /ha. Since then, harvest rates and productivity have decreased substantially to about 20 kg/ha by 1988, resulting in a total estimated fish production of some 740 tonnes per year. Considering that reliable fish catch assessments are extremely difficult the actual situation may be even worse. Nonetheless, the catch statistics available indicate that the reservoir fishery has progressively shifted from the large-bodied top-predators to small-bodied, low-value planktivores. This trend of fishing down food webs is common in fisheries. The data available evidences the trend of individual fishers experience more total catches, but lesser returns from the small fish harvested. Many researchers examining the problem have suggested giving local villages more control over the regulation of fishing in the reservoir, to facilitate more sustainable fishing practices.[4]

Some reports have also found that the Nam Ngum dam has adversely affected aquatic life downstream. Careful analysis has revealed that water released from the Nam Ngum reservoir has different quality as compared to the water in undammed natural rivers. Specifically the dissolved oxygen levels in the water released from the reservoir are unfavorable for aquatic life most of the year, especially during the wet season. Similarly some reporters have noted an unsafe level of hydrogen sulfide. The dam also actively blocks migration by upland fish into the downstream part of the river, which secludes these fish from active spawning sights. These deteriorations in the water quality and biodiversity of Nam Ngum river, pose a significant risk to the overall river ecosystem.[5]

The Nam Ngum 1 heavily influences local agriculture irrigation. According to the 2005 national census, subsistence-based agriculture is the main form of livelihood generation for the majority of citizens, and 75 percent of the population in basin provinces report agriculture as their primary form of employment. Some government officials and academics have raised concerns about if the water required for hydropower generation could co-exist with the water being used for irrigation expansion. A study from Duke[2] recently used the Nam Ngum dam as a case study to model the effects of current and expanded hydropower usage on the river. The study determined that if high-levels of water availability continue tradeoffs between agricultural and hydropower goals will be modest because with high-levels of water irrigation expansion will not significantly effect hydropower generation or vice versa. However, the study did find that under dry conditions the tradeoff between expanded irrigation and hydropower increases. The study determined that continued hydropower generation and hydropower expansion could become exceedingly difficult in such conditions. This is because future returns from Nam Ngum dam and expanded agriculture are largely dependent on high levels of rainfall and water levels. Accordingly, the expected future economic returns from the Nam Ngum dam as well as agriculture expansion in the Vientiane province would be severely decreased in dry conditions. As a result of the potential impact of dry conditions, there is widespread uncertainty about the future of Nam Ngum 1 and further hydropower project on the Nam Ngum. Some scholars have become concerned that climate change may lead to decreased levels of rainfall. As with fishing in the reservoir, the government of the Lao PDR will likely have to take steps to address hydrology issues in the future.[2]