China’s hydropower dams on the Upper Mekong River (Lancang in Chinese) are preventing flood waters from reaching Vietnam's Lower Mekong Delta, Dao Trong Tu, former vice general secretary of the Vietnam National Mekong Committee, told VnExpress.
“Flood water has failed to arrive in the Mekong Delta in recent years, which is a very dangerous issue,” Tu said.
Flood water from upstream helps balance water levels in the delta and brings sediment that enriches the soil and provides food for fish, while pushing back saltwater intrusion in the Mekong Delta, the expert said.
Flood water usually arrives in the region from August to November, but according to Vietnam’s Southern Hydro-Meteorological Station, water levels in upper parts of the country’s Mekong River are very low, around 50cm down from last year.
Khuong Le Binh, director of the Hydro-Meteorological Station in the southern province of Dong Thap, said there have been no signs that flood water from upstream will reach lower areas this year.
It is estimated that half of the sediment in Vietnam’s Mekong Delta comes from further up the river, but hydropower dams in the Upper Mekong River are blocking it from reaching the lower delta.
Vietnam's Ministry of Planning and Investment estimated that around 45 percent of the country's Mekong Delta will be negatively affected by saltwater intrusion by 2030 if hydropower dams and reservoirs along the Mekong River prevent water from flowing downstream.
China has six hydropower dams operating in the upper areas of the Lancang River, Chinese officials told a group of Vietnamese reporters in mid-June this year.
An official from the Department of International Relations, Science and Technology under China’s Ministry of Water Resources said China holds water in the upper areas but later releases it to lower areas so no water is lost in the end. “When countries in the lower areas are in the rainy season, they do not need much water so China stores it to generate electricity. When the dry season comes, China discharges the water. This process helps prevent floods and droughts in lower areas,” the official said.
Vietnam’s Tu, however, disagreed with the Chinese official. He said China uses water as it pleases to generate electricity, not to balance water levels further down the Mekong. Thats why water levels in its reservoirs are purely dependent on demand for power in China.
China discharged water from the Jinghong Hydropower Station in Yunnan Province in March and April this year following requests from countries situated downstream that were suffering from droughts, but many experts said this was only temporary measure to meet the demand in lower areas, especially Vietnam.
Information sharing mechanism needed
One of the main issues facing nations in the Mekong River Commission (MRC), including Vietnam, Thailand, Cambodia and Laos, is that China has refused to share information about the operations of its hydropower dams. As a result, the MRC countries are cautious about using their limited water resources, particularly during the dry season, according to Tu.
The Chinese official confirmed that China does share information with the MRC during the rainy season, but does not during the dry season. He said it was unnecessary to share information during the dry season, and that China was simply following international practices.
The Vietnamese expert, once again, dismissed China’s explanation, saying the Convention on the Law of Non-Navigational Uses of International Watercourses in 1997 defines that information sharing will help ensure cooperation among countries for the whole year.
He said he hopes China will join the MRC so that they can discuss plans to use the Mekong River fairly among the countries involved.
China initiated the Lancang-Mekong Cooperation (LMC) framework in March this year, which includes China, Vietnam, Thailand, Myanmar, Laos and Cambodia, but there have been no concrete cooperation agreements signed between them, according to Tu.
“For cross-border rivers, cooperation mechanisms are very important. One cannot say you go your way I go mine. They [the countries] should cooperate for mutual benefit in a friendly way and based on international law,” Tu said, adding that he hopes the LMC will address the lack of cooperation between China and countries on the Lower Mekong River.
The Mekong River is the world's 12th longest and the 7th longest in Asia. The 4,350km river runs through China, Myanmar, Laos, Thailand, Cambodia and Vietnam.
About 22 million people, or 24 percent of Vietnam's population, live in the Mekong Delta. The delta supplies a large amount of rice, fruit and fish to the country, but negative effects from the El Nino phenomenon and upstream dams have brought about its worst drought and saltwater intrusion in nearly 100 years.