Assessment of an embankment dam break warning system based on historical dam failures

Embankment dams offer many outstanding benefits to the society, but like any built structure, dams also pose potential risks for people or property, especially in densely populated areas. If a dam fails, it results in most of the cases in a catastrophic event. The negative consequences could entail not only large loss of property (besides the dam), but also loss of lives. Principal causes of emba.nkment dam failures are overtopping, internal erosion and problems associated with the foundation. A literature review of historical failure events indicates that there are multiple reasons for dam failure (e. g. a large precipitation, a human mistake, an intentionally act, etc.). Furthermore, most of the cases report that darn crest depressions and other signals were observed at an early failure phase. The conventional monitoring measurements could not give reliable information at the failure begin, in case they were available. Hence, in many cases the failure detection at the dam occurred too late, which reduced the time for executing the mitigation plan downstream. Embankment dam warning systems are often part of large dams and some selected small dams. The investigation of historical failure events (including the reported warning times) showed that there is tl1e need of an improved warning system detecting failures at an early stage. This paper proposes an embankment dam break warning system, which could be based on the distributed temperature and strain sensing technology (DTSS). The proposed concept offers not only a long term monitoring along the dam crest and the location of a problem, but also the possibility of extending the warning time by early failure detection.