Radio Free Asia (RFA) has taken first prize for Outstanding Online Reporting on the Environment for its 2010 multimedia series “The Last Untamed River.”

The prize, awarded by the Society of Environmental Journalists on Thursday, is in recognition of RFA’s investigative reporting trek down the Mekong River.

It will be presented in Missoula, Montana, on October 13 at the SEJ’s 20th annual conference.

“This award is a tremendous honor,” RFA President Libby Liu said Thursday. “We know from our listeners that the health of the Mekong River is of paramount importance to their quality of life, and in some cases, to their very existence.”

The Mekong River — the least developed of the world’s major rivers — sustains more than 60 million people from the Tibetan plateau to the South China Sea.

RFA’s series, with original reporting in English adapted into seven Asian languages, comprises 22 high-quality videos, along with blogs, graphics, slideshows, and other social media releases.

It addresses climate change and melting glaciers, urbanization and industrialization, the decline of forests and fisheries, and finally the development of China’s dams and control over water flow, as seen by ordinary citizens — from nomadic herders and fishermen — as well as regional experts and analysts. RFA’s videographers traveled for nearly 3,000 miles along the Mekong River from Tibet to Vietnam and the South China Sea.