Mekong River - Kratie

Photos: Sayan Chuenudomsavad

Mekong at a crossroad

The new dam planned in Luang Prabang has triggered another wave of opposition_and questions on the Mekong values.

As the formal “prior consultation” process has been kick-started for the fifth dam on the Lower Mekong, Luang Prabang, half way of those 11 planned on the Lower section of the 5, 000-km Mekong River, the lifeline of Southeast Asia, Bangkok Tribune would like to invite readers to look back at the pros and cons of hydropower development plans assessed by the river’s regulating body, Mekong River Commission, dubbed as the most comprehensive assessment ever.

Known simply as the Council Study, the Study on the Sustainable Development and Management of the Mekong River, including Impacts of Mainstream Hydropower Projects, was a result of strong disagreement by Mekong country members particularly Vietnam against the first dam planned on the section, Xayaburi.

During the MRC’s prior consultation process for the Xayaburi Dam,  initiated in late 2010, Vietnam called for dam building to be suspended for ten years while more studies on potential impacts were requested, following the recommendations in the Strategic Environmental Assessment (SEA) commissioned by the MRC to assess proposed hydropower projects against their cumulative risks and opportunities. 

In 2011,  the MRC agreed to implement the Council Study to provide a basin-wide assessment of the “cumulative impacts” of planned dams to supplement project-by-project decision-making and support a basin-wide planning.

Or in other word, the study was expected to help advise MRC member countries_Cambodia,  Lao PDR,  Thailand, and Vietnam_on the positive and negative impacts of water resources development in the Mekong Basin. 

From 2012, the secretariat completed the study in December 2017. It then reported to 4 Mekong prime ministers the key messages from the study, followed by the releases of the document and related maeterials up until last month.

Credit: MRC

The Council Study

Throughout the years, a number of experts helped one another assess current and potential future development plans of the Mekong countries in six water-related sectors _ hydropower, land use, irrigation, navigation, flood protection and industry . They also predicted both positive and negative impacts across economic, social and environment spheres.

To achieve this, the Council Study came up with three main water resource development scenarios: the 2007 early development scenario (baseline), the 2020 definite future scenario (medium-term plan), and the 2040 planned development scenario (long-term plan) (plus climate change in its sub-scenerios).

The 2007 scenario (including existing mainstream dams _Manwan and Dachaoshan_in Upper Mekong Basin, or Lancang in Chinese) represents the “baseline conditions” in the LMB. It is used against which the others are compared. 

The 2020 definite future scenario, called as ‘2020 plans’, includes all  existing,  under-construction,  and  firmly-committed developments  in the  six sectors, including  the Xayaburi  and Don Sahong hydropower  projects  on the Mekong mainstream. 

And the 2040 planned development scenario, called as ‘2040 plans’, includes 2020 developments plus developments in the six sectors planned for implementation  by 2040.

China-Laos Railway Bridge crossing Mekong River - Luang Prabang
The new railway across the Mekong River in Luang Prabang. (Photo: Sayan Chuenudomsavad)

The key messages

In regard to the so-called “water resources development”, the Council Study has listed both potential benefits and potential adverse impacts to be considered.

On the front of potential benefits, the study has found that hydropower sector makes up “almost half of the growth potential” of the four sectors (hydropower, fisheries, agriculture and navigation) combined. 

It further notes that hydropower development can increase electricity security. Increased access to electricity from hydropower or other energy sources has the potential to improve the livelihoods of rural communities and reduce costs in the agricultural sector such as for sprinklers and water pumps.

Meanwhile, expansion of agricultural areas in combination with increasing irrigation capacity as a result contributes to food security, increasing rice production and reducing production variability. 

Increased flow of the Mekong River during the dry season due to discharges from hydropower may be beneficial for irrigated agriculture in certain river reaches and reduce sea water intrusion in the Mekong Delta, the study notes.

For navigation, the River stretches with sufficient water depth from the dams improve navigation and reduce the need for dredging, allowing larger vessels to navigate year-round. Development of navigation enhances the low-carbon waterway transport of cargo and passengers and may enhance river tourism, the study notes.

The study also notes that flood and drought issues may be better managed through responsible and joint operation of those hydropower dams that are able to store water during the wet season and assist in the management of flood peaks downstream. Flood protection works in the areas at most risk, it says, can offset the predicted increase in future flood damage. 

But such the waster resources development has also cast potential adverse impacts.

The Council Study points that the developments proposed are likely to “reduce resilience and increase vulnerability” of rural communities in the Mekong impact corridor, with the main benefits going to power companies and consumers mainly outside the corridor at the expense of fishing and rural households.

The “connectivity related impacts” of mainstream and tributary hydropower dams, such as trapping of sediment, disruption of fish migration paths, and alteration of flow regimes, “are substantial and far-reaching”, and overshadow those of all other planned water resource developments in the LMB. 

In addition, trapping of bed and suspended sediment in tributary and mainstream dams of the Mekong Basin, including China, significantly increase river erosion in the LMB, requiring significant expenditure on bank protection in Cambodia and Viet Nam’s Mekong Delta, and reduce the deposition of nutrient-rich sediment on floodplains with low soil fertility. 

The study further notes that reservoirs created by mainstream hydropower dams, the construction of bank and flood protection structures, and barriers to fish migration have wide-ranging ecosystem impacts, especially on Mekong fish species.

Reduction in the wet season flood pulse limits the duration, depth and extent of inundation of floodplain habitats and therefore reduces productivity, particularly of the Xe Bang Fai floodplains in Lao PDR, the Cambodian flood plains, the Tonle Sap system and the Mekong Delta. 

Meanwhile, agricultural expansion comes at the cost of losing forests and wetlands, accelerated soil erosion, increased use of agro-chemicals, land degradation and reductions in the stocks of natural capital, and associated flows of ecosystem services, the study notes.

Navigation-related channel improvement activities, their maintenance, the construction of infrastructure such as ports and operational activities, the study points, can potentially affect the environment and fisheries.

Rapid industrialization and urbanization, in addition, tends to result in the pollution of water bodies adjacent to development areas, where untreated wastewater is discharged into natural water systems or leached into soils.

Mekong River - Savannakhet
Small-scale fishery at Savannakhet, Lao PDR. (Photo: Sayan Chuenudomsavad)

Overall picture

The Council Study projects that economic benefit of the hydropower sector spanning across 24 years from 2017 to 2040 would increase in all LMB countries. Under the modelled scenarios, Thailand would be the main beneficiary of Lao mainstream dams, and Viet Nam the main beneficiary of mainstream dams in Cambodia, due to returns on investments and power purchases. 

Investment returns related to mainstream dams would also flow to non-Mekong countries, such as China and Malaysia, the study notes.

On the front of the economic benefit of the agricultural sector, the study notes that it is likely to increase with the planned agricultural land expansions (including irrigated agriculture); particularly in Cambodia, but also in Viet Nam and Lao PDR, whereas in Thailand the agricultural land stays the same. 

For all countries, except Viet Nam, irrigation is also further developed, it says.

For navigation, the study also says both 2020 and 2040 plans increase the economic benefit in the LMB. Viet Nam would be the main beneficiary, followed by Cambodia, Thailand and Lao PDR. 

Investments in the navigation sector boost cargo and passenger transport, especially in Viet Nam. Changes in total cargo value and passenger numbers constitute important flow-on effects for the broader economy, the study projects.

“The comparison of the four sectors _hydropower, fisheries, agriculture, and navigation_suggests substantial economic improvements for the 2020 and 2040 scenarios,” the study points.

Li of fish trap at Khon Phapheng Waterfall
A traditional fishing gear at Si Phan Don, Lao PDR. (Photo: Sayan Chuenudomsavad)

The losses

Frist and foremost is the capture fisheries sector that is likely to experience a substantial decline in economic benefits for the 2020 and 2040 scenarios. 

From a macro-economic perspective, the fisheries sectors in Lao PDR and Thailand are likely to lose most of their economic relevance, the study points.

Overall, the changes to the fisheries sector through hydropower development are “substantial” and likely to change the market structure for fish throughout the LMB. To what extent aquaculture could provide relief has not been considered, the study adds.

For sediment input and transport downstream, the study projects that total sediment loads entering the Mekong River under the 2020 and 2040 scenarios may increase due to land use changes. On the other hand, there may be a drastic reduction in the amount of sediments actually transported downstream towards the Mekong Delta due to trapping in the growing numbers of dams, although it may be mitigated.

Critically, the riverine ecosystem health of the LMB is predicted to decline through the development sequence: towards moderately modified to completely modified in 2040, according to the study.

Fish biomass, in addition, is anticipated to decline under 2020 and 2040 scenarios, especially in the upper  part  of  the  LMB,  and  in  particular  white  fish,  the  biggest  contributor  to  fish  biomass  in  the LMB. Changing environments, such as reservoirs, on the other hand, are expected to increase generalist and non-native fish, the study points.

“Inshort, the comparison of the scenarios shows that the 2020 and 2040 plans are likely to result in sustainability losses,” the study concludes.

Credit: MRC

What does it mean?

The study has concluded that the development plans combine a group of highly beneficial and a  group of nonbeneficial  hydropower  and  agricultural  expansion  projects.  These plans, it says, are not optimal and sustainable from a basin-wide perspective.

They would trigger a decline in resilience and increase vulnerability in the Mekong impact corridor as food and income security may not improve proportionately unless benefits from these developments are distributed appropriately, besides reducing GDP growth for excessive investment and externalities.

“Poverty  levels across the scenarios, therefore, are predicted to be modest, but nevertheless increase overall,” the study says.

The study points that the trade-offs between hydropower development and  fisheries are “substantial”. The impacts on fish species composition and  biomass cannot be totally eliminated even with advanced mitigation measures, it notes.

Climate change, in addition, is likely to amplify negative impacts, particularly under the drier climate scenario, and poses a significant risk to both food security and GDP growth in the LMB, particularly  for  Cambodia. 

These include impacts from sea level rise,  such as  more salinity intrusion, variability in mean annual flows of the Mekong River, and extreme flood and drought conditions, the study says.

“In the absence of cross-sector benefit sharing, the sustainability index of the LMB countries would drop substantially if current national development plans were implemented,” the study has concluded.

Mekong River - Xayaburi, Lao
The mighty river of Mekong at Xayaburi. (Photo: Sayan Chuenudomsavad)

Key recommendations

The study suggests comprehensive integrated energy and water planning  on a basin scale be conducted,  and adjustments in planned investments in hydropower and agriculture are needed  to reduce or avoid substantial ecosystem and sustainability losses.

Only low impact and high return hydropower and agricultural projects should  proceed to implementation, it has suggested.

As current development  scenarios combine both highly positive and negative hydropower and agriculture projects, the study has suggested project-by-project assessments that adequately consider “cumulative impacts” be conducted.

“To minimize and monitor environmental risks and impacts, performing  transboundary and cumulative environmental impact assessments, and joint environmental monitoring and adaptive management  is “a must” for all planned water resource development projects. 

“Investments in emerging energy generation technologies should continue  to be explored. Current and future energy planning should consider replacing potentially high adverse impact hydropower projects by more  sustainable forms of power generation such as solar and wind power where appropriate, possibly in combination with hydropower plants,” the study has suggested.

Above all, there are lives and way of life of the Mekong people between the lines that are valuable but cannot or may not be measured in monetary terms.

Source: The MRC’s Council Study

Read more:
Mekong’s Way
Luang Prabang Dam takes one more step close to construction with consultation process kickstarted and opposition