The collapse of Two Dams in Inner Mongolia; Worst Fears have Come True!!
According to the official website of the Ministry of Water Resources of China, between 8:00 p.m. on July 17th and 2:00 p.m. on July 18th, heavy to severe rainfall occurred in Morin Dawa Banner of Hulunbuir City, an Autonomous Region in Inner Mongolia. At 1:48 p.m. on July 18th, a dam collapsed at Yongan Reservoir on a tributary of the Nuomin River in Mo Banner; after the collapse of the dam, a large amount of floodwater rushed into Xinfa Reservoir 13 kilometers downstream, causing another dam to collapse at about 3:30 p.m. at Xinfa Reservoir, which has a capacity of 38 million Cubic Metres.
According to mainland media reports, the people of the four downstream villages have been evacuated, and authorities have yet to announce casualty numbers. On the night of the 18th, the flood has merged into the mainstream of the Nuomin River. Flooding caused the G111 national highway in Mo Banner to collapse, causing road disruptions. Downstream villages and farmlands have been turned into a sea of water.
It is reported that 16,660 people were affected by the dam breach, and 54,000 acres of farmland were flooded. The flood also destroyed 22 bridges, 124 culverts, 15.6 kilometers of highways, and 20 kilometers of road shoulders.
From information on the web, we know that Xinfa Reservoir was built in 1958 and started operation in 1959. No information was found on Yongan Reservoir, but it’s said that the two reservoirs went through reinforcement and maintenance in 1997. It’s estimated that the two reservoirs were built around the same time.
According to 2021 statistics from the Ministry of Water Resources, there are 98,000 reservoirs in China, including 4,700 reservoirs with a capacity of 10 Million to 1 Billion cubic meters, and 94,000 reservoirs with a capacity of 100,000 to 10 million cubic meters. More than 80% of them were built in the 1950s and 1970s, and more than 95% before the 1980s. The information shows that over 95% of China's reservoir dams are earth and rock-fill dams, and their lifespans are usually only about 50 years. Therefore, most of the dams in China have exceeded or are approaching the end of their design life.
According to the statistics of dams from 1954 to 2001, the annual rate of dam failures in China reached 0.088%, while the average annual rate of dam failures overseas since 1900, excluding those caused by war, is 0.02% in the United States, 0.004% in Japan, and 0.02% on average in the world. Therefore, the average annual rate of dam failures in China is more than four times the world average.
In August 2013, flooding across six provinces in China resulted in many deaths and injuries due to dam collapses. In an article titled "China's Dangerous Dams: 179 Cities Facing Dam Collapse," the Chinese media outlet NetEase News said that more than 84,000 small and medium-sized reservoirs in China lack funds for management and maintenance, and that dams would collapse from time to time. As a result of reservoir and dam problems, 179 cities, a quarter of all cities in China, and 285 counties, a sixth of all counties, are facing serious risks.
Last year, China experienced the most severe flooding since 1998, causing damage to 131 large and medium-sized reservoirs and 1991 small reservoirs.