Vital Statistics, Facts and Images

Vital ASDSO Statistics and Facts

  • The average age of the more than 90,000 dams in the United States is 56 years old.
  • The number of high-hazard potential dams is almost 15,500 in 2016.
  • Hazard Rating refers to consequences of a dam's failure, not the condition of the dam.
  • To rehabilitate the nation's non-federal and federal dams it would cost more than $64 billion.
  • To rehabilitate the most critical dams only, it would cost almost $22 billion.
  • By 2025, 7 out of 10 dams in the United States will be over 50 years old.
  • As of 2016, 79% of state-regulated High-Hazard Potential dams have Emergency Action Plans (EAPs).
  • Over half of the dams in the United States are owned by a private entity.
  • A dam is considered high hazard if a failure or mis-operation is expected to result in loss of life and may also cause significant economic losses.

National Statistic Graphs

Dam Safety Total State Budget

Total NID Dams by Hazard Classification 

State-Regulated High Hazard Portential Dams with an EAP

Dam Ownership

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Causes of Dam Failures


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Perfect to Imperfect Dam - Maintenance (YouTubeDownload)
Overtopping Failure (YouTubeDownload)
Piping Failure (YouTube, Download)
Slope Failure  (YoutubeDownload)
Hazard Creep (YouTubeDownload


ASDSO Logo (email for permission)

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