Possible to have same power with less damage with alternative Mekong dams

Apr 18, 2011
Across the Greater Mekong region people utilise healthy wetlands and rivers for fish and other aquatic resources. Credit: Leslie Leong

A new study by WWF on aquatic ecosystem connectivity reveals that the Mekong region could have equivalent power but dramatically less damage to river functioning by opting for tributary rather than main channel dams.

Poorly evaluated and uncontrolled dam development could also take the Mekong to a tipping point past which vital natural processes, such as sediment- and nutrient transport and fish migration, could no longer be taken for granted, WWF warned.

“No part of the Mekong River still provides connectivity to all the 13 ecosystem types classified by a recent WWF study,” said Nikolai Sindorf from WWF Conservation Science Program. “The impact of continuing incremental dam development will disconnect more-and-more ecosystem processes.”

“Where it gets alarming is the disproportional amount of negative impact from dam construction on the lower mainstream of the river such as Xayaburi, a dam proposed in northern Laos.   The Mekong is extremely sensitive to the impacts of mainstream dams because of its layout - a very long mainstream fed by relatively short tributaries.“

Xayaburi, the first of 11 dams proposed for the Mekong stream, is projected to produce 1260 MW of power while reducing the basin’s total connectivity by five percent.  In contrast the 1070MW Nam Theun 2 dam on the Nam Theun River in Laos took only 0.8 per cent out of the Mekong’s connectivity, and the 1540MW Se San cascade of 6 dams decreased connectivity by just 1.2 per cent.

The proposed Xayaburi dam would cut 9 aquatic ecosystems upstream out of a total of 13 using WWF’s classification. Meanwhile, both Nam Theun 2 and the Se San cascade only block a single ecosystem in much smaller parts of the basin.

Ecosystem connectivity is critical to maintain the river and its reproductive processes. The study shows graphically that the 50 larger dams located on tributaries already cause serious interruptions to relevant river processes. In the new study, which quantifies the fragmentation by cumulative dam development on the Mekong river system by WWF scientists,  “ecosystem connectivity” was measured by the overlap of those ecosystem processes vital to river functioning under an array of conditions such as land cover, hydrology and seasonal factors.

“The impact of basin-wide planning on ecosystem connectivity needs to become one of the measures against which projects are assessed,” said Dang Thuy Trang, Manager, Sustainable Hydropower and River Basin Programme, WWF Greater Mekong Programme. “This will make it easier to develop the Mekong basin with a much lower environmental footprint. Ultimately, this would lead us to a situation where local energy demands are met, and relevant ecosystem processes are conserved basin-wide.

WWF is calling for a 10-year delay in the approval of the mainstream dams to fully consider the costs and benefits of their construction and operation. Immediate energy needs can be met from multiple hydropower projects on some selected Mekong tributaries where connectivity impacts are disproportionally lower.

Explore further: Nepal to end rescue operation on trekking route

add to favorites email to friend print save as pdf

Related Stories

UN study advises caution over dams

May 21, 2009

(AP) -- A dam-building spree in China poses the greatest threat to the future of the already beleaguered Mekong, one of the world's major rivers and a key source of water for the region, a U.N. report said ...

Dracula fish, bald bird among strange new species

Oct 06, 2010

Dracula fish, a bald songbird and a seven-metre (23 feet) tall carnivorous plant are among several unusual new species found in the Greater Mekong region last year, researchers said Wednesday.

Dam removal increases property values

Apr 17, 2008

Two new studies appearing in Contemporary Economic Policy explore the impact of dam removal on local property values and find that property values increase after dams are removed.

Water-related conflicts set to escalate

Apr 30, 2010

Population growth, urbanisation, increasing pollution, soil erosion and climate variations are all reflected in the management and adequacy of the world's waters. The situation is particularly difficult in many developing ...

Recommended for you

Nepal to end rescue operation on trekking route

3 hours ago

Nepal was wrapping up rescue operations in its northern mountains Monday, saying all the hikers believed to have been stranded on a trekking route by a series of deadly blizzards are now safe.

Major breakthrough could help detoxify pollutants

17 hours ago

Scientists at The University of Manchester hope a major breakthrough could lead to more effective methods for detoxifying dangerous pollutants like PCBs and dioxins. The result is a culmination of 15 years of research and ...

Heavy rains leave 22 dead in Nicaragua

Oct 19, 2014

Days of torrential rains in Nicaragua left 22 people dead and left homeless more than 32,000 others, according to an official report Saturday.

Plastic nanoparticles also harm freshwater organisms

Oct 18, 2014

Organisms can be negatively affected by plastic nanoparticles, not just in the seas and oceans but in freshwater bodies too. These particles slow the growth of algae, cause deformities in water fleas and impede communication ...

User comments : 0