Banqiao Dam Failure

Banqiao dam failure and his history is discus in these slides.It was located in China.Reason of Banqiao Dam is also discused.

1. 26 NOVEMBER 2019 Banqiao Dam Presented By (702,709,718,723 & 724)

2. 2 Construction of the Banqiao dam began in April 1951 on the Ru River. The help of Soviet consultants as part of a project to control flooding and provide electrical power generation. The construction was a response to severe flooding in the Hua River Basin in 1949 and 1950. The dam was completed in June 1952. Because of the absence of hydrology data the design standard was lower than usual. After the 1954 Huai River great flood, the upstream reservoirs including Banqiao were extended, constructed, and consolidated. Banqiao Dam was increased in height by three meters. History of Banqiao Dam

3. 3 The dam crest level was 116.34 meters above sea level and the crest level of the wave protection wall was 117.64 meters above sea level. The total capacity of the reservoir was 492 million m 3  (398,000-acre feet), with 375 million m 3  (304,000-acre feet) reserved for flood storage. The dam was made of clay and was 24.5 meters high. The maximum discharge of the reservoir was 1742 m 3 /s. Banqiao Dam

4. 4 Cracks in the dam and sluice gates appeared after completion due to construction and engineering errors. They were repaired with the advice from Soviet engineers and the new design, dubbed  the iron dam , was considered unbreakable. Chen Xing one of China's foremost hydrologists was involved in the design of the dam but he was also a vocal critic of the government's dam building policy which involved many dams in the basin. Banqiao Dam

5. 5 He had recommended 12 sluice gates for the Banqiao Dam, but this was criticized as being excessive and the number was reduced to five. Other dams in the project, including the Shimantan Dam, had a similar reduction of safety features and Chen was removed from the project. In 1961, after problems with the water system were revealed, he was brought back to help. Chen continued to be an outspoken critic of the system and was again removed from the project. Banqiao Dam

6. Abstract During 4–8 August 1975, an extreme storm occurred in Henan Province, China. The maximum 5-day rainfall reached a record of 1,631 mm. Two large dams (Banqiao Dam and Shimandan Dam) two medium dams (Tiangang Dam and Zhugou Dam) and 58 small dams failed from overtopping in the storm event. 6

7. 7 The breach peak flow rate was as high as 78,100 m 3 /s from the Banqiao reservoir and 30,000 m 3 /s from the Shimantan reservoir. The breaching of these dams caused an inundated area of 12,000 km 2 , a death toll of over 26,000, and economic loss of more than RMB10 billion. This paper introduces 26 dam failures in a smaller region of Zhumadian, i.e., Banqiao Dam, Zhugou Dam, and 24 small dams. The catastrophic event is described in detail especially for Banqiao Dam and Zhugou Dam. The causes and mechanisms of the principal failures are discussed, as well as the influence of an upstream dam failure on the downstream dams. Lessons from the catastrophe are discussed. Continue…

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9. Reasons of the Banqiao Dam Failure Understanding In August of 1975, typhoon Nina pelted the region with the heaviest rains ever recorded in the area. More than a year’s worth of water fell in 24 hours. The previous record was 800 mm (31.5”) of rain, and the stalled typhoon Nina dropped a new record of 1060 mm (41.73”). 9

10. 10 The rainfall caused massive downstream flooding and, because of the flooded downstream areas, one request to open the dam was rejected on August 6. On August 7, the request to open the dam was accepted but this information did not reach the dam, as the storm had brought down the telegraph wires.   The under-designed sluice gates were unable to handle the water volume and the first dam failure warning was sent. The water crested on August 8 at 0.3 meter (0.0984’) higher than the protection wall on the dam, which failed. 62 other dams in the Huai river basin also failed. Reasons of the Banqiao Dam Failure

11. 11 The Banqiao Dam failure caused a huge wave, 10 kilometers (6.2 miles) wide and 3-7 meters (9.8-23ft) high to rush downstream at 50 kilometers per hour (31 mph), inundating the lower area with speeding floodwaters. Approximately 26,000 people died from flooding and another 145,000 died afterward as a result of epidemics and famine. Some 5,960,000 buildings collapsed, and 11 million residents were affected. Unofficial estimates of the number of people killed by the disaster have run as high as 230,000 people. Reasons of the Banqiao Dam Failure

12. 12 Environmental Impacts Visible:  Floods (river, coastal, mudflow), Large-scale disturbance of hydro and geological systems, Reduced ecological / hydrological connectivity Environmental impacts Dam failure Health Impacts Visible:  Accidents, Exposure to unknown or uncertain complex risks (radiation, etc…), Deaths Impacts of Banqiao dam failure:

13. 13 Health impacts The largest dam failure ever, over two hundred thousand deaths. Socio-economical Impacts Visible:  Displacement, Loss of livelihood, Specific impacts on women, Violations of human rights, Land dispossession, Loss of landscape/sense of place. Impacts of Banqiao dam failure:

14. 14 Within eleven years of the dam failure, the lower reach of the River Ru Zhumadian City, experienced several more disastrous floods. After many feasibility studies, the new Banqiao Reservoir reconstruction was listed as a key national project of The Seventh Five-Year Plan of China. The project owner was Huai River Water Resources Commission. The construction contractor was Changjiang Gezhouba Engineering Bureau. Reconstruction

15. 15 By the end of 1986, the rebuilding project commenced. On June 5, 1993, the project was certified by the Chinese government. The reconstructed Banqiao Reservoir controls a catchment area of 768 km 2 . The maximum reserve capacity is 675 million m 3  (178 billion gallons), a capacity increase of 34% above the capacity of the failed dam. The effective storage is 256 million m 3  (67.6 billion gallons) and the corresponding normal high-water level is 111.5 m (366 ft) above sea level Reconstruction

16. 16 The flood control storage is 457 million m 3  (121 billion gallons). The dam is made of clay and is 3,720 m (12,200 ft) long and 50.5 m (166 ft) high. The dam crest level is 120 m (390 ft) above sea level. The maximum discharge of the reservoir is 15000 m 3 /s (about 3.96 million gallons/s). Reconstruction

17. THANK YOU! MUHAMMAD NAWAZ SHREEF UNIVERSITY OF ENGINEERING AND TECHNOLOGY