This post was originally published on the WLE Greater Mekong blog and was written by Dr. Xuezhong Yu who is the lead researcher on MK22: Balancing River Health and Hydropower Requirements in the Lancang River Basin.
In March 2016, Vietnam proposed for China to increase its outflow from the Jinghong Hydropower Station to the Mekong River to cope with drought and salt intrusion in a number of Vietnam’s Mekong Delta provinces. In response to Vietnam’s request, China agreed to release more water from its Jinghong Hydropower Station reservoir into the lower Mekong River in order to deal with drought in Vietnam. The water release at the Jinghong Hydropower Station was increased to 2190 m3/s on March 15 and was maintained around 2000m3/s from March 15 to April 10.
As many as 140,000ha of rice have been damaged so far, nearly 90,000 ha of which resulted in a 70 percent loss of crop across the Mekong Delta region – Vietnam’s largest rice producer. The salt invasion appeared two months earlier than before in the delta region, and the invasion length of mainstream reach was 40-93km. In addition to Vietnam, other countries in the Mekong river basin are also suffering the worst drought in recent decades.
According to the information released by the State Flood Control and Drought Relief Headquarters of China, the watershed runoff yield in the Lancang River Basin decreased by 20% since this year. The inflow to the cascade hydropower stations is only 500m3/s. The operation of the cascade hydropower project reservoirs was optimized so that Jinghong released discharge at 1000m3/s. The increased water volume released at Jinghong is 2.7 billion cubic meters so far and is 94% more than inflow. In order to alleviate the drought situation in the Mekong delta region, the Chinese government decided to further increase the release discharge to 2000 m3/s within 27 days. In Chiang Saen, the water level in the Mekong began rising rapidly from 2.3-2.5m on March 15 to 3.29m on March 18 evening.
Read the rest of the post on the WLE Greater Mekong blog.