U.S. Fish & Wildlife Service Low Hazard Dams - Association of State ...

damsafety.org

U.S. Fish & Wildlife Service Low Hazard Dams - Association of State ...

STANDING OPERATING PROCEDURESCHAPTER 6EMERGENCY ACTIONS TO PREVENT A DAMFAILURE OR MINIMIZE EFFECTS OF FAILURE6.1 Common Causes of Dam Incidents and FailuresUnderstanding the risks and reasons for dam incidents including failure is a first step in anyeffort to improve dam safety, prevent a dam failure, or minimize the effects of failure. Damfailures are usually the result of poor design, improper construction, improper operation,inadequate maintenance, deterioration from aging, or a combination of these factors. Thefundamental causes of dam incidents and their relative percentage of occurrence is summarizedin Table 6-1.Table 6-1Causes of Dam IncidentsCausePercentageEarthquake Instability 1Faulty Construction 2Gate Failure 2Sliding 10Embankment Deformation 11Spillway Erosion 14Overtopping 25Seepage/Piping 35Natural hazards such as floods, earthquakes, and landslides are important contributors to damincidents. The most important natural hazards threatening dams are floods. Human behavior isanother element of dam failure risk; simple mistakes, operational mismanagement, negligence,unnecessary oversights, or destructive intent can interact with other hazards to compound thepossibility of failure.Flood fighting is an art, and can be extremely difficult to execute. There is no absolute methodthat one can apply to guarantee success. However, failure to react in a timely manner and applyproven flood fighting techniques greatly increases the risk of failure. Although each flood isunique, there are many common elements from one flood to the next, and plans and preparationswill improve your response time and success.The action to be taken upon the discovery of a potentially unsafe condition will depend on thenature of the problem and the time estimated to be available for remedial or mitigation measures.As time permits, one or more of the following actions will be required:6-1Revision No. 0October 2008

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