The Banqiao Reservoir Dam Failure - Essay Example

The Banqiao Reservoir Dam Failure Abstract The collapse of the Banquio and Shimantan Dams together with a several dozen much smaller dams in the Zhumadian Prefecture of Henan Province in China in August 1975 is among the world’s most devastating dam failures (Graham, 1999). Initially, it was reported that the dam failure was attributed to a natural disaster. However many years later and after considerable research, researchers have come to the conclusion that the Banqiao Reservoir Dam’s design and the design of the other reservoirs, together with the standards associated with containing the river are partly responsible for the dam failure. In essence it is now generally accepted that the Banqiao Reservoir Dam failure was due to both man-made error/engineering failure and a natural disaster. This study investigates the main causes of the Banqaio Reservoir Dam failure and the implications when one or more dams depend on the sustainability of other dams. To this end, this paper sets out a description of the engineering disaster and explores the engineering factors contributing to the engineering disaster. Table of Contents Abstract 1 Introduction/Background 3 Dam Specifications 3 The Disaster 4 Evaluating the Engineering Failures of the Banqiao Dam Collapse 4 The Investigation of the Banqiao Dam Failure 7 Conclusion 11 Introduction/Background Dam Specifications Zhumadian is situated in the Southern region of Henan Province with Hong and Ru Rivers running east through Zhumadian converging upon the Huai River. The Banqiao Dam was constructed on the Ru River in 1952 as part of the flood control programme for the Huai River. In 1956, the Banqiao Dam was reconstructed elevating the dam height and improving the capabilities of the reservoir. The Banqiao Dam was constructed so that it could withstand “1-1in-1,000 year flood (306mm rainfall per day)” (Xu, Zhang, & Jia, 2008, p. 164). The Banqiao Dam was described as a “clay-core earthfill dam” measuring 24.5 meters in height with the ability to store up to 492 million meters and with a further 375 million cubic meters “reserved for flood control” (Xu, et. al., 2008, p. 165). The crest of the Banqiao Dam was 6 meters in width and 2020 meters in length with elevation at 116.34 meters. The parapet walls elevation was 117.64 meters. The discharge capacity was built for 3,092 cubic meters with 1,800 cubic meters accounting for the main spillway, 1,160 cubic meters were designed for the supplementary spillway and 123 cubic meters designed for the conduit (Xu, et. al., 2008). The Disaster The collapse of the Banqiao Dam began on the evening of August 7, 1975 when a large storm became stationery over the Henan Province. As a result the deluge sustained over a foot of rain daily for a period of three days (Chiles, 2001). The rainfall dumped by the storm amounted to 1005 mm of rain in a day’s time and 1605 mm of rain over a three day period. In one hour, flooding overtopped the Banqiao and Shimantan dams leading to their collapse (Eliasson & Lee, 2003). In all, over 60 smaller dams collapsed because “dikes and flood diversion projects further downstream could not resist such a deluge” (Eliasson & Lee, 2003, p. 620). Land measuring over one million hectares also sustained flooding, more than 100 km of the railway line connecting Guangzhou to Beijing sustained damages, many villages and towns were either entirely or partly submerged in water and several million residents became homeless. Conservative estimates report that some 26,000 persons drowned in the flood directly linked to the failed dams and an additional 145, 000 eventually died as a result of causal famines and epidemics in the weeks that followed (Eliassin & Lee, 2003). Evaluating the Engineering Failures of the Banqiao Dam Collapse Becker (1998) puts the construction of the Banqiao Dam and the associated dams in its proper perspective. According to Becker (1998) the Banqiao Dam was constructed around a time where irrigation was a prime agricultural policy. At the time each of China’s counties were required to erect water reservoirs by the construction of dams and water ways. A number of larger projects that were already in construction such as the Yellow River’s Sanmenxia Dam were hastened (Becker, 1998). Upon reflection, an official from the Ministry of Agriculture noted in the 1990s that virtually all of the smaller reservoirs constructed during the 50s and subsequently were “completely worthless” (Becker, 1998, p. 77). A majority of the dams had failed by the time they were three years old while the Yellow River’s dam “quickly filled up with silt, rendering it next to useless” and today it is minimally operational (Becker, 1998, p. 77). Although a few dams survived a bit longer, they eventually collapsed with disastrous results, the worst being the Banqiao Dam (Becker, 1998). Much of the work used for the construction of the dams was sub-standard. Virtually all of the builders were scarcely equipped and resorted to using “the simplest tools” and were forced to toil long hours, often on daily and nightly shifts and were accommodated in “makeshift tents” receiving food only while they were working (Becker, 1998, p. 77). Becker (1998) goes on to explain: The peasant labourers were organized in military units and marched to work following flags, with marital music blaring from loudspeakers. On the larger projects, tens of thousands were conscripted as labourers and paid nothing (p. 77). For the most part, the Chinese were committed to competing with the large dams constructed in the USSR. Impressed by Soviet Dams such as the Dnieper and the Volga-White Sea canal, Chinese officials were committed to not merely replicating these efforts but were determined to complete the “greatest construction undertaking in history” (Becker, 1998, p. 78). The plan emanated from a program designed to channel excessive water from the Yangtze into the Yellow River. The idea was to channel water via a conundrum of interconnected systems consisting of canals, tunnels, ravines, lakes and dams. Construction commenced during the Great Leap Forward which was an economic plan focusing on agriculture and irrigation in China beginning in 1957 (Bramall, 2009). The construction of dams and irrigation channels was purported to take 7 years to execute and would use millions of men in labor. Reports during the construction era indicated that Chinese peasants had moved far more rock and soil in one day than the workers constructing the Panama Canal had managed to move in 10 years. Becker (1998) reports that: A total of 6, 560 million cubic feet was excavated in the week ending December 12, 1959. This is more than 12 times the amount shifted for the building of the Panama Canal (p. 78). In rural China, dams were primarily made of soil as opposed to concrete and as a result they broke. Moreover, the dams were constructed and designed by “untrained peasants” rather than by trained engineers (Becker, 1998, p. 78). The Chinese Communist Party were not impressed by formal education and were actively promoting the work of Le Heyun, a peasant “water conservancy engineer” described as a “bold innovator” and an “advanced worker” (Becker, 1998, p. 78). During the erection of the Huangtan reservoir in 1959, Le Heyun recommended substitute conduit and culverts rather than concrete as a means of saving money. It was later discovered that in the construction of many of the dams, concrete was scarcely used and this accounted for the collapse of a majority of the dams (Becker, 1998). Chetham (2002) reports that out of 80,000 dams constructed in China during the first 40 years of the founding of the Republic, approximately 110 dams failed each year from 1950 to 1980 with a documented 554 failures in 1973. The Banqiao and Shimantan dams were built after the Soviet models and were described as “indestructible iron dams” (Chetham, 2002, p. 186). In fact, the Banqial Dam was constructed with the aid of Soviet consultants. However, shortly after construction, cracks appeared in the dam and its sluice gates “due to construction and engineering errors” (Shaw, 2011, p. 17). The cracks were repaired however and it was after these repairs the dam was described as “iron” and “unbreakable” (Shaw, 2011, p. 17). In the final analysis, the cause of the Banqiao collapse is primarily attributed to engineering failure. A majority of the dams constructed during the Great Leap Forward were built by untrained workers with no real technical knowledge or engineering skills. Moreover, the construction of the dams were rushed and in doing so, failed to come close to achieving the lofty goal of the constructing the greatest project in history. Although the storm is partially responsible, given the history of construction and the collapse of dams constructed beginning in the Great Leap Forward, the Banqiao Dam and the interconnected dams and waterways were poorly constructed to begin with and would have eventually collapsed. The Investigation of the Banqiao Dam Failure The official report coming out of China in the days following the collapse of the Banqiao Dam indicated that the failure was due to the storm, Typhoon Nina. Thus an investigation of the Dam failure was minimal. Only years later, with investigations and studies by engineers and researchers were the pieces of the puzzle finally put together. An investigation of documents and historical accounts reveal that it was impossible to transmit communication to and from the dam around August 7, 1975 because buildings connected to the dam had collapsed as a result of heavy rains and wires failed. On August 6th there had a been a request to open the dam but the request was denied as a result of the floods in the downstream area. However, the following day on August 7, the request was allowed, but the dam personnel did not receive the telegram (Shaw, 2011). The sluice gates were unable to cope with the water overflow due in part to “sedimentation blockage” (Shaw, 2011, p. 18). At approximately, 9. 30 p.m. on August 7, the People’s Liberation Army at the Banqiao Dam dispatched the first warning that the dam failed by telegraph. Just after midnight, August 8, 1975, the Smimantan Dam collapsed and 10 minutes after the Liberation Army asked for permission to open the Banqiao Dam. At 1.00 a.m. on August 8, 1975, the “Banqiao crested 117.94 level above sea level, which was 0.3 meters higher than the wave protection wall on the dam” and it subsequently failed (Shaw, 2011, p. 18). This set off a chain reaction with 62 dams failing altogether. Shaw (2011) explains: The runoff of Banqiao Dam was 13,000 cubic meters per second inflow vs. 78,000 cubic meters per second outflow, and 701 million tons of water was released in 6 hours, while 1.6 million tons of water was released in 5.5 hours at upriver Shimantan Dam, and 15.7 billion tons of water was released in total (p. 18). The minimal investigation conducted by Chinese officials commenced with summit held by the National Flood Prevention and Reservoir Security in Zhengzhou, Henen and chaired by the Department of Water Conservancy and Electricity. At the conclusion of the summit a national reservoir security investigation was conducted. The official results of the investigation revealed that the dam failure was attributable to unpredictable or misinterpreted weather conditions (Shaw, 2011). It was reported that rainfall predicted by the Beijin Central Meteorological Observatory only called for 100 millimeters of rain. This was understandable because at the time, Chinese meteorologists could not provide a more accurate forecast “given their scientific knowledge” (Shaw, 2011). Even so, water resources researchers, some thirty years later have reported that: ...the design of those reservoirs and the guiding principles to contain the mighty Huaihe River should be blamed for such a calamity (Shaw, 2011, p. 19). Li Zechun, a weather forecaster and among the first to arrive at the scene of the tragedy and who is now an academic at the Chinese Academy of Engineering Sciences noted that the weather forecasting is not solely responsible for the collapse of the Banqiao Dam. Zechun goes on to state that the “tragedy was a man-made calamity rather than a natural one” (Shaw, 2011, p. 19). According to Zechun, the: ...water storage for irrigation function of a reservoir was overemphasized amid a reservoir construction heat in the late 1959s despite warnings by some scientists that much of a reservoir’s flood control was ignored (Shaw, 2011, p. 19). For example, the Banqiao Reservoir was constructed with the ability to cope with 492 million cubic meters but it was forced to cope with over 697 million cubic meters during the flooding (Shaw, 2011). The chaos that followed was only exacerbated by the fact that the early warning system appeared to be non-existent and with communications knocked out by weather conditions the tragedy that unfolded was inevitable. The engineering errors in terms of poor construction were particularly problematic since China has a history of flooding. With a history of flooding, more care should have been put into the construction of the Banqiao Dam and the surrounding dams. The fact is, once floods occur other damages occur. The environment becomes damaged because flooding impacts chemical plants and chemical are absorbed by the environment. It therefore follows that constructing dams requires assuming responsibility for safeguarding as far as humanly possible against the possibility of flooding (Shaw, 2011). Therefore in the construction and maintenance of dams it is necessary to work in collaboration with a body of experts from meteorology, hydrology, the environment, forestry and agriculture (Shaw, 2011). Moreover, an early warning system is imperative. Thus in the construction of Dams, setting up facilities for communication channels is also necessary. It would appear however that in the construction of the Banqiao Dam and the other interlocking dams, ethics and standards of safety was secondary to meeting a lofty and unrealistic goal: the largest construction project in history. As Vesilind and Gunn (1998) argue: Engineers, as professionals, have a special responsibility to the public, and this responsibility is often expressed in terms of professional ethics (p. xi). Obviously, the engineers constructing a dam have a special responsibility to take into account the environmental damages that could occur in the event there is an engineering failure. However, it is difficult to impose these ethical standards on the peasants who were exploited in the construction of the dams designed and built during the Great Leap Forward. Even so, the peasants were merely following instructions from someone who invariably assumed the position of design engineer. Thus at some level between the peasants and the government officials, someone was accountable to the public and thus bound by the ethical standards imposed upon engineers. Regardless, ethical standards were not taken into consideration in the construction of the Banqiao Dam and the surrounding dams or any of the dams constructed during the Great Leap Forward. The main consideration was the construction of large dams, unlike any dam ever constructed and at an unprecedented pace. In the meantime, the dams were to be constructed at minimal cost to the government. However, in the end it cost the government more in terms of loss of life, damage to property and the necessity of compensating for the losses and damages. Conclusion Storms and other natural disasters are predictable and as such engineers in the design and construction of dams that are vulnerable to these natural disasters have an ethical responsibility to take the possibility of those disasters into account. However, as evidenced by the Banqiao Dam disaster, political intervention and oversight can compromise an engineer’s ethical responsibilities to the public. The political drive to save money and accomplish an unrealistic goal prevailed over any engineering ethics. In fact, it is doubtful that any qualified engineers were involved in the actual design and construction of the Banqiao Dam or any of the other dams constructed pursuant to the Great Leap Forward plan. Regardless, the exploitation of peasants, the lack of tools and a general lack of technical know-how precludes the conclusion that the Banqiao Dam disaster is purely related to weather conditions and inaccurate weather reporting. The mere fact that substandard tools and workers were used in the construction of the dams and the dams were built of poor material and rushed to completion immediately raises suspicions that the dams collapsed as a result of engineering failure. Moreover, the fact that storms and flooding are common in the areas, the dam should have been designed and constructed with the possibility that weather conditions may be entirely sever or inaccurately forecast. References Becker, J. Hungry Ghosts: Mao’s Secret Famine. New York, NY: Henry Holt and Company, LLC, 1998. Bramall, C. Chinese Economic Development. Oxon, UK: Routledge, 2009. Chetham, D. Before the Deluge: The Vanishing World of the Yangtze’s Three Gorge. New York, NY: Palgrave MacMillan, 2002. Chiles, J. R. Inviting Disaster: Lessons from the Edge of Technology. New York, NY: HarperCollins Publishers Inc., 2001. Eliasson, B. and Lee, Y. Y. Integrated Assessment of Sustainable Energy Systems in China: The China Energy Technology Program. The Netherlands: Kluwer Academic Publishers, 2003. Graham, W. J. “A Procedure for Estimating Loss of Life Caused by Dam Failure.” US Department of the Interior, Bureau of Reclamation, DSO-99-06, September 1999, 1-46. Shaw, K. “Wivenhoe: A Dam Designed to Fail and Decimate Brisbane.” A Report to the Flood Commission of Australia, 4 April, 2011, 1-84. Vesilind, A. and Gunn, A. S. Engineering, Ethics, and the Environment. Cambridge, UK: Cambridge University Press, 1998. Xu, Y.; Zhang, L. and Jia, J. “Lessons from Catastrophic Dam Failures in August 1975 in Zhumadian, China.” In Reddy, K. R.; Khire, M. V. and Alshawabkeh, A. N. (Eds). Geosustainability and Geohazard Mitigation. New Orleans, Louisiana: Geocongress, 2008, 162-169. Read More