Abstract: Nassim Taleb's book, The Black Swani, argues that there are rare events that have never been encountered before and therefore cannot be anticipated. He further argues that since we cannot anticipate these events we cannot assess the risks they represent until after such an event has occurred. In essence he argues that there are cases where the epistemic uncertainty, the lack of fundamental knowledge, is 100% and any attempt to analyze and assess the associated risk is hopeless. The terrorist attacks of September 11, 2001 on the World Trade Center Buildings in New York are often characterized as Black Swan events as are many dam failures.
Studies of dam failures and safety related incidents shows that most were not caused by a single, easily analyzed, component failure or an extreme loading condition but rather by interactions between various components and subsystems. To assess the safety of a dam in a more complete manner we must use tools that allow the analysis of system failure modes and use our knowledge and imagination to hypothesize system failure modes that we are unaware of. In other words, we must imagine the Black Swans. 
By utilizing concepts embodied in systems engineering techniques we can take a more holistic approach to dam safety than is possible under the more common standards or risk-informed approaches. This paper discusses systemic contributions to dam failures and ways researchers are developing methodologies to analyze system failure modes and assess the associated risks.

Key words: dam, system, dam failure

摘要： 纳西姆·塔雷伯在其著作《黑天鹅》中声称，之前能真正发生和遭遇稀有事件的机会很少，因此，很难预见到。他更进一步阐述，因为不能预见到这些事情的发生，所以直到事件真正发生之前都不能评估其会带来的风险。本质上，他的核心观点是对于某些案例，百分百会存在认知上的不确定性和基础知识的缺乏，并且，任何想分析和评估其相关风险的尝试都是徒劳的。2001年9月11日对纽约世贸中心大厦进行的恐怖袭击，通常就被定性为黑天鹅事件，其他许多大坝失事案例也一样。
对大坝溃决和对与事故相关的安全进行研究，结果表明：大多数事故不是由单一的、容易分析的、某一组成部分的失事或极值负荷工况引起，而是各个组成部分和子系统相互联系、相互作用引起事故。为更彻底地评估大坝的安全，必须使用可以分析系统失事模式的工具，并使用所获取的知识和想象来假设之前没意识到的系统失事模式。换句话说，必须设想黑天鹅事件。
通过应用系统工程技术中的概念，相比于可能采用的更常用的标准或风险确定的方法，可以形成一种较全面的方法应用到大坝安全中来。笔者讨论了大坝失事的系统成因和研究人员正在开发的各种方法，以分析系统失事模式并评估相关风险。

关键词: 大坝, 系统, 大坝失事