The Associated Press
By PANYAPAT PIYATHAMSAWAT

BANGKOK -- A recently built dam in southern China is hurting the livelihoods of thousands of villagers downstream in Myanmar, environmental activists said Tuesday in the latest complaint about management of Southeast Asian rivers that cross national boundaries.

Two groups associated with Myanmar's Shan ethnic minority said in a new report that the hydropower dam on the Longjiang River in China's Yunnan province causes changes in the river's level that hinder traders dependent on water transport.

Groups in several countries have criticized China's construction of dams on the Mekong River and other waterways because of their impact on downstream communities. Beijing has rejected charges that its dams are to blame.

The report, "High and Dry," by the Shan Sapawa Environmental Organization and the Shan Women's Action Network, said local trade and transport on the river in northern Myanmar near a border trade crossing with China has been severely affected by unpredictable daily changes in the water level since the completion in mid-2010 of the 360-foot- (110-meter-) tall Longjiang Dam about 19 miles (30 kilometers) upstream.

The report estimated that some 16,000 villagers - ferry operators and the traders and services that depend on them - have had their incomes decline drastically, as boats face both grounding and flooding.

"The Longjiang dam represents an example of what we are facing," said Premrudee Daoroung of the Bangkok-based, nonprofit Foundation for Ecological Recovery, speaking at a press conference. "First, the issue of the ecosystem of the river needs to be considered. What happens upstream can have an immediate affect on downstream people. "

The reports said it was encouraging that "Chinese government officials have begun to publicly state their commitment to the ecological integrity of transnational rivers and to developing the Mekong River for the 'mutual benefit' of all countries along the river."

But it also called for Chinese authorities "to investigate and mitigate the disruptive impacts of the dam" and to make cross-border impact assessments for any future dams built in China.

In April, China strongly rejected claims that its dam-building policies are environmentally harmful. It held a one-day meeting with leaders of the four Mekong Basin nations - Thailand, Laos, Cambodia and Vietnam to address climate change and other challenges to the health of the Mekong River.

The meeting in Thailand of the member-nations of the Mekong River Commission, along with China and Myanmar - through which flow the upstream reaches of the river - came as the Mekong's water levels were at their lowest in nearly 20 years.

The commission's scientists said this year's low flow and consequent drought could be attributed to an early end to the 2009 wet season and low rainfall during the monsoons.