The water reservoirs and hydropower stations on the upper reaches of the Mekong River should not be blamed for the drought in Southeast Asia, the president of the International Commission of Large Dams said on Wednesday.

In fact, the severe drought has revealed the water infrastructure along the Mekong River is "inadequate" to effectively fight droughts and floods, Jia Jinsheng told China Daily.

Dams have been built since a century ago; in the dry season, they release water to add to the supply, while in the rainy season, they hold back water to help reduce the damage, he said.

Dams built on the Yangtze and Yellow rivers, two of China's longest, have been proven effective in doing both, he added.

Of the eight dams China planned to build on the 4,880-km Lancang River, which flows through Yunnan province into Southeast Asia where it is called the Mekong River, three are operational.

Without the reservoirs and other water conservancy projects in Southwest China, this year's drought would have been worse, he said.

Jia admitted there is negative impact from building dams, all of which - including those built in developed countries - harm biological diversity and the environment to some degree.

"The key is to strictly follow globally-accepted standards and minimize that impact," he said, adding that building more water conservancy infrastructure will be a long-term task for developing nations.

Jia said China does not channel water away from the Lancang River, and that all hydropower stations in Yunnan have undergone strict environmental and ecological evaluations.

Liu Ning, vice-minister of water resources, expressed similar sentiments at a press conference on Wednesday: "It is not right to say reservoirs have 'hijacked' water resources."

Zhou Xuewen, head of the ministry's planning department, said the water blocked by China's dams on the Lancang River accounts for only 3 percent of the total flow in the river, which is "too little to influence the lower-reach countries in Southeast Asia".

"It is unlikely that our dams are worsening the drought in the Mekong River basin," Liu Ning said.

Pich Dun, secretary-general of the Cambodian National Mekong Commission, told Xinhua on Monday that a drop in the Mekong water level was caused by poor rainfall and climate change rather than dams on the Lancang River.

"The Mekong River Commission (MRC) has found no evidence that the dams on the upper reaches have an impact on the water flow downstream," he said.

Instead, the water flow in lower parts of the Mekong River in the dry season was much higher after the dams were built, thanks to hydropower stations releasing water to generate power, he said.

"A study conducted by the MRC in February found that the drought in the lower Mekong region or northern Laos and Thailand was caused by an early end to the rainy season, while the drought in Southwest China including Yunnan province was caused by climate change, or climatic cycles," the secretary-general said.

He said the MRC's four members - Cambodia, Laos, Thailand and Vietnam, and its dialogue partner China enjoy close ties.

The Mekong River Summit starting on Friday in Hua Hin, Thailand, will focus on enhancing ties among countries along the Mekong River, the Asian Development Bank and ASEAN to ensure sustainable development in the region, he said.

An MRC Hua Hin Declaration will be issued on climate change and challenges to sustainable development.

Vice-Minister Liu said China will cooperate with its neighbors along the Mekong River to explore and use water resources scientifically for common interest.