The Mekong River Commission (MRC) announced new technologies Thursday to see if big hydropower projects have significant impacts on water quality and flow as well as fish populations.

In a statement, the MRC said it showcased two new sets of equipment on Tuesday at Don Sahong Dam — less than two kilometres upstream from the Cambodian-Lao border.

The first will monitor water level and quality immediately below the dam – and report if anything adversely affects that quality – in near real-time.

"This is vital for the millions of fishing and farming families who rely on the Mekong, even for drinking water,” the intergovernmental agency said.

The second set of equipment involves an acoustic telemetry system with tags attached to migratory, transboundary fish species.

As dams may disrupt fish migrations, developers are expected to install fishways allowing fish to typically move upstream to spawn and downstream to feed.

“However, to date there’s been no way to prove if the Don Sahong fish passage works as intended.”

The new tagging system is expected to provide evidence, as it tracks fish movements up and downstream through several natural-like fishways.

These include the Hou Sadam and Hou Xangpheuk channels, which the developer modified.

“Effective policies require accurate data,” MRC Secretariat chief executive Anoulak Kittikhoun said.

“It’s important for us to understand if and how the dam affects water flow and quality. Likewise, if the fish passage works.

"Then, if needed, we’ll propose appropriate measures for the dam to adjust its operations,” he said.

Dr. Kittikhoun noted tagging's value for future projects.

“The findings and recommendations can also be made for similar dams, so they can build one that doesn’t just generate electricity, but also functions harmoniously with people’s livelihoods – through fisheries resources and other river ecosystems.”

The statement said the need to better monitor Mekong water quality had “grown obvious” over the years.

Since launching its Water Quality Monitoring Network (WQMN) in 1985, the MRC was limited to measuring water quality manually on a monthly basis.

Data was submitted only at year’s end, with no warning of a sudden change in quality.

“Moreover, the Don Sahong station wasn’t even a WQMN member – so shared no data with the MRC,” the statement said.

But the Malaysian dam operator has now joined a pilot MRC-joint environmental monitoring project and water quality will be measured automatically every 15 minutes.

Information will then be sent to the central MRC database in Vientiane and forwarded to MRC members — Cambodia, Laos, Thailand and Vietnam — as well as riverine communities.

“It’s important for all of us to understand the correlation between changes in water level and water quality – as quickly as possible,” Lao Natural Resources and Environment Vice Minister Chanthanet Boualapha said.

“This station is in a technically advantageous location to monitor this, as well as cost-effective, because both types of equipment fit into one house.

“The location is accessible year-round, which makes it easy for relevant agencies to maintain,” the vice minister said.

As for monitoring fish movements through modified channels, delicate tagging of fish is required.

If tagged fish aren’t locating or using the passages, "those details will help inform the dam developer,” the statement said.

“They’ll then be expected to consider modifications or alternative solutions to facilitate fish migration.”

If it tracks fish through the channels, tagging is expected to be applied elsewhere, expanding regional knowledge of fish migration and spawning.

“There are many variables,” said Lee Baumgartner, a freshwater fish ecologist and professor at Charles Sturt University in Australia.

“Some species of fish don’t like the tag,” Baumgartner said. “Some do like it. The environment is the most important factor.

“The technology works extremely well in big lakes, oceans, or deep rivers, but we’ll find out how well it works in small channels, shallow water, fast water, or water with a lot of rapids.

"We’ll know more in two or three months’ time.”

The joint environmental monitoring project is funded by the MRC members and development partners including Germany and Australia.

Source: Agency Kampuchea Press