HUA HIN, Thailand, April 5 (Reuters) – China on Monday denied that its dams were reducing water levels on the Mekong River and blamed problems along the river on unusually dry weather, but it also offered to share more data with its neighbours.

Leaders of Thailand, Cambodia, Vietnam and Laos, badly hit by the Mekong’s biggest drop in water levels in decades, met in the Thai coastal town of Hua Hin to discuss management of Southeast Asia’s longest waterway. Some 65 million people depend on the river.

China sent vice foreign minister Song Tao to rebut criticism of the eight hydropower dams it has built or is building in its south.

“Statistics show the recent drought that hit the whole river basin is attributable to the extreme dry weather, and the water level decline of the Mekong River has nothing to do with the hydropower development,” Song said in an official statement after the meeting.

The Mekong originates in the Tibetan plateau and flows 4,800 km (2,980 miles) through rice-rich areas of Myanmar, Thailand, Laos and Cambodia before emptying into the South China Sea off Vietnam.

Song said southwestern China was suffering its worst drought in decades. Beijing says the drought has left about 18 million people and 11 million animals with insufficient drinking water and affects 4.3 million hectares (10.6 million acres) of crops.

Activists and environmentalists say China has not provided relevant data to assess the impact of the dams on water flows.

But Song said it had given rainy season data since 2003 and dry-season data from two hydrological stations since March in response to requests from its four downstream neighbours through the intergovernmental Mekong River Commission (MRC).

Environmental organisations in the lower Mekong basin, particularly in Thailand, have long accused China of a lack of transparency in water management policies.

In particular, they are demanding more detailed data from Xiaowan hydroelectric dam on the upper reaches of the Mekong. Xiaowan, China’s second-largest hydroelectric station, began storing water in its reservoir last October.

Government officials in the four Mekong countries are more guarded in their comments, mindful of trade and investment flows. Thai Prime Minister Abhisit Vejjajiva told reporters the dialogue with China had been positive, commending the powerful northern neighbour for cooperation and for providing data.

“The heart of effective management of the water is information sharing. I am optimistic it will become more systematic and more consistent. It will allow for more effective management of the river as well as building of trust,” he said.

ONE STEP FORWARD

Activists said giving data was a step in the right direction.

“We need more and we need effective management of available data. But simply breaking that silence is progress for us after years of very little information on what’s going on upstream,” said Pianporn Deetes, spokeswoman for the Save the Mekong Coalition, an alliance of environmental groups.

But Pianporn said the water level problem could not be put down simply to drought and more cooperation was needed.

“If the dams don’t contribute to the loss of water level, China should publicly release information on water level flows that goes back several decades, not just the latest.”

Song said China had responded to the concerns of downstream countries, even at the expense of some hydropower projects.

To prevent any impact on fish migration, Beijing cancelled one hydroelectric plant, the Mengsong, on the upper reaches, Song said, and it was planning to build a counter-regulation reservoir to prevent abnormal downstream fluctuations in water level. (Editing by Alan Raybould and Ron Popeski)