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 more than 15,500 in 2018.
  • 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 $70 billion.
  • To rehabilitate the most critical dams only, it would cost almost $24 billion.
  • By 2025, 7 out of 10 dams in the United States will be over 50 years old.
  • As of the end of Calendar Year 2017, 81% 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

State-Regulated High Hazard Potential Dams with an EAP

Total NID Dams by Hazard Classification

Dam Ownership

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Causes of Dam Failures

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Basic Nomenclature of a Dam


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

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