Dam Safety Data
Analysis computed directly from the U.S. Army Corps of Engineers National Inventory of Dams, published as tables you can read and a CSV you can use. Free to reuse with attribution — if you are a reporter, a county emergency manager, or a researcher, take the file rather than retyping the numbers.
Of 17,049 high-hazard dams in the United States — structures whose failure would likely cause loss of life — 2,476 have no emergency action plan on record, or 14.5%.
2,791 high-hazard dams are rated Poor or Unsatisfactory (504 of them Unsatisfactory, the lowest rating the inventory assigns).
Using this data
Everything here is computed from the raw NID national extract rather than quoted from secondary reporting, and the extract date is stamped on every page. NID reflects what state and federal programs have reported to USACE: it can lag a state program's own records, and an "EAP Prepared: No" flag means no plan is recorded rather than proof that none exists. Cite it as inventory data, not as a compliance finding.
Attribution: source data U.S. Army Corps of Engineers, National Inventory of Dams; analysis by Michael Flynn, PE, PE-Calc. A link back to this page is appreciated and is what keeps the analysis being updated.