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TABLE OF CONTENTS 31.0 WHAT IS THE BANQIAO DAM COLLAPSE

4WHAT IS OUR OPINION ON BANQIAO DAM COLLAPSE?

52.0 WHEN DID THE BANQIAO DAM COLLAPSE HAPPENED

53.0 WHERE WAS THE BANQIAO DAM COLLAPSE HAPPENED

64.0 HOW WAS THE BANQIAO DAM COLLAPSE HAPPENED

85.0 WHY WAS THE REASON RESULTING ON BANQIAO DAM COLLAPSE

96.0 WHO WAS INVOLVED IN THE BANQIAO DAM COLLAPSE

107.0 CONCLUSION

118.0 REFERENCES

1.0 WHAT IS THE BANQIAO DAM COLLAPSEThe Banqiao Reservoir Dam is a dam on the River Ru in Zhumadian City, Henan province, China. In 1975, it collapses causing the highest number of death in recorded history. It also causes the immediate loss of power measuring up to 18GW of power, the power output equivalent to about 9 very large modern coal-fired thermal power stations.

The construction of the dam commenced on April of 1951 and finished on June of 1952 with the help of Soviet consultants as part of a project to control flooding and electrical power generation. Because of the absence of hydrological data, the design standard was lower than usual. Chen Xing, one of Chinas foremost hydrologists was involved in the design of the dam. He recommended 12 sluice gates for the dam, but he was criticized for his suggestion as too conservative and the number was reduced to five. Later on, he was removed from the project.

On the whole, the dam failure was cause by natural act as opposed to engineering failures. The dam was initially design to withstand a once-in-1000-years flood, but in August of 1975, a once-in-2000-years flood occurred. More massive than the construction of the dam had accounted for. This is due to the collision of Typhoon Nina and a cold front earlier that year. As a result, more than an annual amount of rain fell in only 24 hours. It was recorded that 18.5mm of water fell every hour which is equal to 1060 mm per day. This number far exceeds the dam average annual rain fall which is only around 800mm per day.

However, it should be noticed that chances of the devastating flood did not go unnoticed. On August 6, a request was made to open the dam. The request was rejected due to existing flood in those downstream areas. On August 7, the request was granted but the telegram failed to reach the proper authorities until only later that day. By that time, it was already too late and in only a matter of 3 hours, the Shimantan Dam broke. Within the hour, the water from the Shimantan had crested at the Banqiao. On August 8, the Banqiao was breached in the aftermath of the typhoon. Over 700 million m of water was released over 6 hours. Approximately 26000 people died from the water and another 145000 died following the epidemics and famine. On top of that, around 6 millions buildings collapsed and 11millions residents were effected.

Within 11 years of the dam failure, the new Banqiao Reservoir reconstruction was listed as a key national project of the Seventh Five-Year Plan of China. The rebuilding project started at the end of 1986 and was completed on June 1993.

WHAT IS OUR OPINION ON BANQIAO DAM COLLAPSE?

the major factor that contributes to the dam failure is the poor engineering knowledge as well as the limited statistical hydrology data that should have been obtained beforehand in the process of erecting the dam. But engineers nowadays have better come a long way in learning from the mistakes and disasters that happened in the past. With the advancement in the various technological and scientific fields, it can also be said that the knowledge that we engineers have today is not as limited as it was back in the day. Therefore it is safe to say that failure due to structural integrity failure nowadays that comes from the ignorance of material strength can be put to rest. All that remain is that weather the engineer himself/herself that is competent enough to apply the knowledge.

Furthermore, another key factor that causes the dam to fail was due to the communication delay. This is maybe due to the fact that back in the day they are using telegram system which is clearly not reliable. Therefore, to avoid such disaster from happening in the future, it is of the utmost importance to establish a reliable communication system between the dam operator and the proper required authorities

2.0 WHEN DID THE BANQIAO DAM COLLAPSE HAPPENEDIt happened on the night of August 8, 1975. A heavy storm hits the Henan Province Banqiao Dam. By 1.00am, the dam collapsed and killed an estimated 171,000 lives.

3.0 WHERE WAS THE BANQIAO DAM COLLAPSE HAPPENED

Figure 3.1: Approximate location of Banqiao Dam

TheBanqiao Reservoir Damis adamon theRiver RuinZhumadianCity, Henanprovince, China. Its failed in 1975, killing an estimated 171,000 people (although some reports estimate the number be high as 23000) and destroying the homes of 11 million people. It is considered to be biggest and dam failure in history, with more casualities than any other dam failure.

The Banqiao dam and Shimantan Reservoir Dam are among 62 dams in Zhumadian that failed catastrophically or were intentionally destroyed in 1975 during Typhoon Nina.

It also caused the sudden loss of 18 GW of power, the power output equivalent of roughly 9 very large modern coal-firedthermal power stations.

Figure 3.2: TheBanqiao Reservoir Damafter accident

4.0 HOW WAS THE BANQIAO DAM COLLAPSE HAPPENED

The accident actually begins with a natural disaster that causes a heavy rain which named Super Ninas Typhoon. Below is the details chronology of the incidents.

On July 29, 1975, a tropical disturbance arose from a trough line in the Philippine Sea. The disturbance, Tropical Disturbance 04W, moved southwestward for 36 hours as surface and upper-air circulation became more organized and vertically aligned.

On 31 July, the storm slowed and turned northwestward before rapidly intensifying and shifting to the west-northwest.

The storm reached typhoon status on 1 August and underwent explosive deepening- reconnaissance aircraft data indicated a 63 mb (hPa) drop in sea level pressure at the typhoon center, with maximum surface winds increasing from 120 km/h to 240 km/h (75 mph to 150 mph).

On the following day, the 2nd of August, the peak intensity of 185 km/h (115 mph) was attained approximately 368 kilometers (230 miles) east of Taiwan.

On 3 August with maximum surface winds of 184 km/h (115 mph), the typhoon slowly decreased in intensity as it approached the island, making landfall near the coastal city of Hualien. Much of the typhoons strength was lost as it moved across Taiwans central mountain range, fortunately sparing the islands most populous areas. After the typhoon traveled across Taiwan, it entered the Taiwan Straight (Formosa Strait), the body of water that separates the island from Mainland China. A significantly weakened Nina (peak winds 110 km/h [69 mph]) made a second landfall as a tropical storm near Jinjiang Fujian, China on 3rd August.

It then moved northwest before shifting north and arriving in the east-central province of Henan on 5 August. The storm brought heavy rainfall as it stalled over this area for 3 days. Approximately 1,060 millimeters (41.7 inches) of rain fell during those three days. The storm produced more rainfall in 24 hours than an average years worth of rain in the Henan Province, 800 millimeters (31.5 inches).

By August 8, the Banqiao and Shimantan Dams, which had been built in the province to protect against heavy rainfall, were both filled over their capacity. At the Banqiao Reservoir on the Ru River, the water had reached 118 meters (386 feet) and was still rising- the dam could not release the water as fast as its reservoir was filling.

Early on August 9, the main part of the Banqiao dam collapsed, sending a wall of water 6 meters (19.7 feet) high and 12 kilometers (7.5 miles) wide rushing down the river channel, followed by 600 million cubic meters of water. Thirty minutes earlier, the Shimantan Reservoir reached its maximum capacity and collapsed. One hundred and twenty (120) million cubic meters of water burst forth from the Shimantan dam and within 5 hours, the entire reservoir was empty. In total, 15.738 billion tons of water poured out onto the Henan Province destroying parts of the city as well as 62 smaller dams. Flood diversions and other systems downstream could not handle the rushing waters; dikes collapsed, creating huge lakes. Several dams were intentionally destroyed by Chinese military air strikes in order to release water in desired directions in attempts to protect larger reservoirs and populations from the floodwaters. By the evening of 9 August, floods had reached the Fuyang Area in the Anhui Province, roughly 250 kilometers away (156 miles).5.0 WHY WAS THE REASON RESULTING ON BANQIAO DAM COLLAPSEThe Banqiao Resevoir Dam failure started when a typhoon called Typhoon Nina came across China at that time and the typhoon caused of non-stop raining days. The Banqiao Reservoir Dam was designed in such a way that would allow it to withstand a large flood. The expected type of flood which is 300 mm of rain falls per day. However, was what is known as a once-in-2,000-years flood, more massive than the construction of the dam had accounted for, meaning that more than an annual amount of rain fell in only 24 hours. Records indicatethat 189.5 mm of water fell every hour, which translates to 1,060 mm per day. That far exceeds the province`s average annual rainfall, which is only around 800 mm.

The chances of devastating flood came unnoticed and the request of opening the other dam was rejected since there was another flood in the downstream area. After days of being ignored, the Shimantan Dam broke and right after that which was less than one hour, the water from the dam crested at the Banqiao dam.

After years of studying the incident, the researcher claimed that the failure, it is not 100% came from natural disaster. It was the design of the Banqiao Reservoir Dam and the other reservoirs, along with the principles related to the containment of the river, which should be blamed for the failure and subsequent disaster.

6.0 WHO WAS INVOLVED IN THE BANQIAO DAM COLLAPSEAccording to the Hydrology Department of Henan Province, the tragedy had killed an estimated 171,000 people from flooding and destroying the homes of 11 million people. At first, the tragedy was started with the Daowencheng Commune located downstream was immediately destroyed and 9,600 people were killed instantly. Sequence from the downfall of the Daowencheng Commune, another 62 dams broke and 11 million peoples lives changes. Survivors of the initial flooding was trapped without access to food or clean water and contaminated water caused illness throughout the area. 26,000 deaths were recorded due to the floodwaters, while nearly 145,000 people lost their lives because of epidemics and famine diseases. In addition, about 5,960,000 buildings collapsed aftermath of the tragedy.

7.0 CONCLUSION

In conclusion, it was the design of the Banqiao Reservoir Dam and the other reservoirs, along with the principles pertaining to the containment of the river, which should be blamed for the failure and subsequent calamity. While many pointed fingers at the weather forecast all those years ago, researchers are citing that the tragedy was man-made and not entirely a natural disaster.

During the late 1950s, scientists warned that any given reservoir`s flood control was being ignored and that the irrigation functions of those reservoirs were overemphasized during the heat of the construction frenzy. It has been estimated that China continues to have 87,000 reservoirs across the nation that were built during this low standard construction era and most of these have fallen into serious disrepair. On top of sub-par construction standards, the country also lacked any early warning system as well as an evacuation plan that could have saved lives.

In the aftermath of the devastation, the Banqiao Reservoir reconstruction was considered a crucial national project in The Seventh Five-Year Plan of China, which was a series of important economic and social development initiatives. The rebuilding project lasted from the end of 1986 to June 5, 1993.

Today, engineering programs throughout the world educate students on the devastating history of dam failures and outline the construction methods that need to be taken in order to prevent such a widespread calamity in the future.

8.0 REFERENCES

The Banqiao Reservoir Dam Failure. (2012, June 19). Retrieved April 5, 2015, from

http://engineeringfailures.org/?p=723The forgotten legacy of Banqiao Dam Failure in China. (2013, February 8) http://www.internationalrivers.org/resources/the-forgotten-legacy-of-the-banqiao-dam-collapse-7821 .Retrieved April 5, 2015.

Dams in distress.(October 2012). Retrieved April 3,2015, from http://www.newschinamag.com/magazine/dams-in-distress