Hydropower development will likely deal a serious economic blow to Cambodia, with dire outlooks for its fisheries and rice outputs predicted even under best-case scenarios, according to key findings from the Mekong River Commission (MRC).

Researchers and policymakers representing the MRC’s member states convened in Vientiane, Laos, late last week to discuss findings due to be published in January as part of a massive five-year study on the sustainable management of the Mekong River system, including impacts from hydropower development. Commonly known as the Council Study, the report was commissioned by Prime Minister Hun Sen as well as the leaders of Laos, Vietnam and Thailand in 2011.

In emailed comments, the MRC said that changes in the Mekong’s flow due to dam construction will introduce “negative effects on riparian ecosystems, sustainability and food security associated with fish production” for Cambodia.

Scenarios modelling full hydropower development predict a reduction in lake and floodplain fisheries production of up to 70 percent across the Mekong basin. What’s more, projected annual GDP losses for the Kingdom are on the scale of $3 billion to $5 billion under the Council Study’s development scenarios for 2020 and 2040.

According to Nao Thuok, a secretary of state at the Ministry of Agriculture, Forestry and Fisheries, the government is currently operating on projections of a 16 to 30 percent drop in fish biomass, though he declined to comment on the new data.

Fish production will be driven down by reduced flows in nutrients and sediments, the MRC found, in turn affecting food prices in the region. “[This] will directly affect the livelihoods of the local communities living along the Mekong mainstream and Tonle Sap flood plain,” they said.

The study looked at the impacts of hydropower under different climate change and development scenarios and broke down impacts on the economies, societies, fisheries, agriculture sectors and ecosystems of each country. For Cambodia, the outlook predicts poor resiliency and sustainability if all the currently planned hydropower developments were to go ahead. It also notes that Cambodia will see a few benefits from dam construction which, in addition to power generation, has the potential to provide better flood control and benefit irrigation.

In order to address the threats shown by the data, the MRC said countries would have to significantly improve the way they collectively manage the shared waterway. Among the recommendations is the creation of development and planning policies between Cambodia and other Mekong countries. Moreover, the MRC suggests governments “consider other emerging energy technologies that are competitive with hydropower”.

At a national level, countries need to have strategies to mitigate the negative impacts that are predicted.

“Strengthen human capital and investment in industry and services [sectors]; modernize agriculture and irrigation sectors, and promote aquaculture to ensure the sustainable growth of GDP,” are among the recommendations.

According to Thuok, of the Agriculture Ministry, alternative sites for the construction of the planned Sambor Dam in Kratie are being considered, with “minimal impact” guiding the final choice. For hydropower in general, “each site should be studied” for its impacts, he said.

Offsetting risks to food security, the MRC noted, requires reducing labour demand for agriculture and improving the management of the soil.

In emailed comments, Watt Botkosal, the Cambodian government’s liaison to the Council Study, said he generally accepted the study’s methods and findings, but noted that limited data provided by some countries may call into question some results.

Still, he said that for the Kingdom, changes in water quality will be significant by 2040, and the completed construction of several dams has already resulted in the decline of many fish species.

Under the predicted scenarios for 2020 and 2040, Botkosal wrote, “there would be a tremendous loss of fish species, agricultural produc[tion], declining fish catch, effect of people livelihoods, poor communities, income reduction, and risk for food security”.

If all 11 planned Mekong mainstream dams are built, he added, the resulting block of fish migration would cause a decline in “most species” of fish.

Botkosal echoed the MRC’s policy recommendations when it came to charting the Kingdom’s future, adding that agencies dealing with water resources need to be strengthened. And while the government has declared its interest in hydropower development, Botkosal noted that alternative energy sources also need to be exploited.

“Solar [power] generation systems are competitive with hydropower with [regards to] protection of fish, sediment, and no resettlement of people,” he wrote.

United Nations Food and Agriculture Organization (FAO) Cambodia representative Alexandre Huynh noted that despite the importance of freshwater fisheries to Cambodia’s food security, those who depend on them for their livelihood “tend to be marginalized from the decision-making processes”.

“This can directly impact their access to and management of the fish resources upon which they depend for food security and nutrition,” he said in an email, noting that this in turn puts human well-being and environmental sustainability at risk.

“The MRC Council study has highlighted the extreme vulnerability of Cambodian freshwater fisheries to water management decisions in [upstream] countries, including those concerning hydropower and irrigation development,” he continued.

When it comes to mitigation measures currently being considered that are described in the study, such as dam features that are touted as not harming fish, Huynh notes “there is relatively little practical evidence of their effectiveness”.

Even if those worked, broader issues relating to changing water flows and their impact on fisheries would remain.

“The consequent impact on nutrition, food security, local livelihoods and customs has not been adequately modelled and plans for compensation or substitution are not in place,” he wrote.

The Ministry of Environment did not respond to requests for comment.

Updated: 7:24pm, Wednesday December 27 2017