Dams and Landslides

Hidden problems with China’s dams

A respected Chinese publication investigates why more than one-third of the country’s dams and reservoirs are considered dangerous, and quotes a top hydropower engineer as saying, “There is something wrong with the whole management system.”

This is a summary of “an in-depth investigation” published by 21st Century Business Herald (Ershiyi shiji jingji baodao) on June 12, 2003.

21st Century Business Herald
August 1, 2003

According to Ministry of Water Resources statistics, 30,413 of China’s reservoirs, or 36 per cent of the total, are considered badly functioning and dangerous; 145 of these are classified as large, 1,118 as medium-sized, and 29,150 as small.

Hunan, Hubei, Jiangxi and Anhui provinces have the highest number of badly functioning and dangerous reservoirs. Hunan leads the list with 6,092 such reservoirs (45 per cent of the province’s total), followed by Hubei (1,791 bad reservoirs, 31 percent of its total), Jiangxi (1,627 bad reservoirs, 18 per cent of its total) and Anhui (1,416 bad reservoirs, 30 per cent of its total).

Poorly functioning and dangerous reservoirs have resulted in numerous dam collapses, caused by overtopping (when too much floodwater has been stored), structural weaknesses and bad management. In addition, as many as 10,000 reservoirs were damaged by floods last year alone and are in urgent need of repair, according to an official in the Reservoir Management Department of the Ministry of Water Resources.

In an interview, Li Lei, chief engineer at the Ministry’s Large Dam Security Management Centre, cited several problems with China’s dangerous reservoirs.

First, overtopping linked to inadequate flood-control capacity is the main reason dams have collapsed. More than 70 per cent of small, badly functioning reservoirs in Ningxia, Shandong and Xinjiang have insufficient flood-control capacity, and this is also the case for as many as 13,600 small reservoirs nationwide.

Second, water leakage and seepage are also major problems, especially with small reservoirs. Since most of China’s dams were built in the 1950s and 1960s, the surveys, design and construction were all inadequate, and undertaken without a clear  understanding of key technical parameters such as valley area, storage capacity,
dam-foundation and upstream-runoff issues. So leakage and seepage, observed in 16,000 small reservoirs in China, has become another major cause of dam collapses.

Third, collapses have been caused by structural weaknesses, such as when dams walls are too thin or slopes are too steep. Cracks and landslides plague many dams and reservoirs as a result, especially in Shandong, Hebei and Hunan provinces. About half the dams in Sichuan are afflicted with such problems.

Finally, other threats to dam safety in China include inadequate safeguards related to seismic activity; communication failures linked to floods; termites; and hidden problems with diversion channels and outlets.

Why are there so many problems?

Jia Jinsheng, deputy director of the China Academy of Hydropower and Water Conservancy, said in an interview that the government and water-resources authorities have attached more importance to dam building than to dam research, management and maintenance, and more importance to big dams than to small ones.

“There is something wrong with the whole management system,” Mr. Jia said. Funding for preliminary studies has been in short supply. And the state has failed to channel special financial resources toward studying how to deal with badly functioning and dangerous dams and reservoirs.

“Management by different levels – is partly responsible for these problems,” said  engineer Li Lei. The Ministry of Water Resources is in charge of dozens of big dams, such as Xiaolangdi in Henan and Panjiakou in Hebei. Medium-sized dams are managed by water-resources bureaus at the city or county levels, while small reservoirs are the responsibility of townships or villages, which do not manage or maintain them well for lack of funds.

At a national conference on strengthening dangerous dams held in 2001, Zhang Jiyao, China’s vice-minister of water resources, disclosed that 68 per cent of water-conservancy departments receive no funding from the central government. The remaining 32 per cent have difficulty raising enough money to be able to maintain dams and reservoirs adequately.

After the 1998 floods, both the central and local governments paid more heed to basic construction activities in the water-conservancy sector, such as bolstering and building flood embankments, with budget allocations reaching record levels. More than US$22 billion was poured into the work between 1998 and 2003.

“With the current system of ‘management by different levels,’ the problem is that small dams and reservoirs, which account for most of the national total, get the least money for repair and maintenance,” said Fu Qunhua, deputy director of the Jiangxi Big Dam Security Inspection Centre.

Li Lei suggested drawing on the experience of the United States, where dams and reservoirs, regardless of size, are run by a special corporation that oversees their operation, management and maintenance, using revenue from power generation, water supply, fishery and tourism. Only one task is left to governments: inspection.

Wu Zhongru, a member of the Chinese Academy of Engineering and a professor at Hehai University in Nanjing, underscored the importance of dam and reservoir maintenance. “Lacking basic knowledge, officials have treated dams as being just as simple as concrete. They are good at coming up with funds and impromptu inspections before floods, but then do nothing after the floods. Meisha reservoir in Anhui, Gutian in Fujian, Longyangyuan in Qinghai, and Qingtongxia in Ningxia all still have hidden problems even after repair, and we have to be very careful about them.”

Jia Jinsheng of the China Academy of Hydropower and Water Conservancy, who is also deputy chief secretary of the China Large Dams Association, said: “If only 1 per cent of the money allocated [by the central government to water-conservancy projects] was put into maintenance, we wouldn’t have to worry about badly functioning and dangerous dams and reservoirs.”

Translated by Mu Lan, editor of the Chinese edition of Three Gorges Probe.

Further reading:
Vice-minister says 73 small dams a year have collapsed in China

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