Risky reservoirs: Pennsylvania counties where aging dams pose the greatest threat

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- Total high-hazard dams: 17
- Number potentially dangerous: 1 (5.9%)
- Potentially dangerous dams include:
--- 1 not rated

#50. Chester County
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- Total high-hazard dams: 16
- Number potentially dangerous: 1 (6.3%)
- Potentially dangerous dams include:
--- 1 not rated

#49. Allegheny County
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- Total high-hazard dams: 25
- Number potentially dangerous: 2 (8.0%)
- Potentially dangerous dams include:
--- 1 posing immediate threat
--- 1 not rated

#48. Greene County
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- Total high-hazard dams: 11
- Number potentially dangerous: 1 (9.1%)
- Potentially dangerous dams include:
--- 1 in poor condition

#47. Lancaster County
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- Total high-hazard dams: 11
- Number potentially dangerous: 1 (9.1%)
- Potentially dangerous dams include:
--- 1 condition withheld

#46. Mercer County
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- Total high-hazard dams: 40
- Number potentially dangerous: 4 (10.0%)
- Potentially dangerous dams include:
--- 3 in poor condition
--- 1 condition withheld

#45. Washington County
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- Total high-hazard dams: 15
- Number potentially dangerous: 2 (13.3%)
- Potentially dangerous dams include:
--- 2 in poor condition

#44. Blair County
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- Total high-hazard dams: 7
- Number potentially dangerous: 1 (14.3%)
- Potentially dangerous dams include:
--- 1 in poor condition

#43. Jefferson County
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- Total high-hazard dams: 14
- Number potentially dangerous: 2 (14.3%)
- Potentially dangerous dams include:
--- 1 in poor condition
--- 1 condition withheld

#42. Carbon County
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- Total high-hazard dams: 21
- Number potentially dangerous: 3 (14.3%)
- Potentially dangerous dams include:
--- 2 in poor condition
--- 1 condition withheld

#41. Butler County
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- Total high-hazard dams: 6
- Number potentially dangerous: 1 (16.7%)
- Potentially dangerous dams include:
--- 1 not rated

#40. Columbia County
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- Total high-hazard dams: 46
- Number potentially dangerous: 8 (17.4%)
- Potentially dangerous dams include:
--- 1 posing immediate threat
--- 7 in poor condition

#39. Pike County
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- Total high-hazard dams: 11
- Number potentially dangerous: 2 (18.2%)
- Potentially dangerous dams include:
--- 2 in poor condition

#38. Bradford County
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- Total high-hazard dams: 5
- Number potentially dangerous: 1 (20.0%)
- Potentially dangerous dams include:
--- 1 in poor condition

#37. Delaware County
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- Total high-hazard dams: 5
- Number potentially dangerous: 1 (20.0%)
- Potentially dangerous dams include:
--- 1 in poor condition

#36. Beaver County
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- Total high-hazard dams: 5
- Number potentially dangerous: 1 (20.0%)
- Potentially dangerous dams include:
--- 1 in poor condition

#35. Sullivan County
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- Total high-hazard dams: 25
- Number potentially dangerous: 5 (20.0%)
- Potentially dangerous dams include:
--- 4 in poor condition
--- 1 condition withheld

#34. Susquehanna County
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- Total high-hazard dams: 14
- Number potentially dangerous: 3 (21.4%)
- Potentially dangerous dams include:
--- 2 in poor condition
--- 1 condition withheld

#33. Fayette County
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- Total high-hazard dams: 9
- Number potentially dangerous: 2 (22.2%)
- Potentially dangerous dams include:
--- 2 in poor condition

#32. Indiana County
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- Total high-hazard dams: 4
- Number potentially dangerous: 1 (25.0%)
- Potentially dangerous dams include:
--- 1 in poor condition

#31. McKean County
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- Total high-hazard dams: 43
- Number potentially dangerous: 11 (25.6%)
- Potentially dangerous dams include:
--- 9 in poor condition
--- 2 condition withheld

#30. Schuylkill County
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- Total high-hazard dams: 31
- Number potentially dangerous: 8 (25.8%)
- Potentially dangerous dams include:
--- 5 in poor condition
--- 3 condition withheld

#29. Westmoreland County
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- Total high-hazard dams: 18
- Number potentially dangerous: 5 (27.8%)
- Potentially dangerous dams include:
--- 4 in poor condition
--- 1 not rated

#28. Somerset County
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- Total high-hazard dams: 10
- Number potentially dangerous: 3 (30.0%)
- Potentially dangerous dams include:
--- 2 in poor condition
--- 1 condition withheld

#27. Clearfield County
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- Total high-hazard dams: 10
- Number potentially dangerous: 3 (30.0%)
- Potentially dangerous dams include:
--- 3 in poor condition

#26. Wyoming County
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- Total high-hazard dams: 23
- Number potentially dangerous: 7 (30.4%)
- Potentially dangerous dams include:
--- 2 posing immediate threat
--- 2 in poor condition
--- 3 condition withheld

#25. Berks County
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- Total high-hazard dams: 49
- Number potentially dangerous: 15 (30.6%)
- Potentially dangerous dams include:
--- 1 posing immediate threat
--- 12 in poor condition
--- 2 condition withheld

#24. Wayne County
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- Total high-hazard dams: 3
- Number potentially dangerous: 1 (33.3%)
- Potentially dangerous dams include:
--- 1 in poor condition

#23. Dauphin County
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- Total high-hazard dams: 3
- Number potentially dangerous: 1 (33.3%)
- Potentially dangerous dams include:
--- 1 in poor condition

#22. Perry County
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- Total high-hazard dams: 33
- Number potentially dangerous: 11 (33.3%)
- Potentially dangerous dams include:
--- 1 posing immediate threat
--- 8 in poor condition
--- 2 condition withheld

#21. Lackawanna County
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- Total high-hazard dams: 36
- Number potentially dangerous: 12 (33.3%)
- Potentially dangerous dams include:
--- 10 in poor condition
--- 2 condition withheld

#20. Luzerne County
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- Total high-hazard dams: 43
- Number potentially dangerous: 15 (34.9%)
- Potentially dangerous dams include:
--- 2 posing immediate threat
--- 13 in poor condition

#19. Monroe County
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- Total high-hazard dams: 14
- Number potentially dangerous: 5 (35.7%)
- Potentially dangerous dams include:
--- 1 posing immediate threat
--- 3 in poor condition
--- 1 condition withheld

#18. York County
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- Total high-hazard dams: 8
- Number potentially dangerous: 3 (37.5%)
- Potentially dangerous dams include:
--- 1 posing immediate threat
--- 1 in poor condition
--- 1 condition withheld

#17. Crawford County
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- Total high-hazard dams: 13
- Number potentially dangerous: 5 (38.5%)
- Potentially dangerous dams include:
--- 5 in poor condition

#16. Cambria County
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- Total high-hazard dams: 5
- Number potentially dangerous: 2 (40.0%)
- Potentially dangerous dams include:
--- 2 in poor condition

#15. Lebanon County
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- Total high-hazard dams: 5
- Number potentially dangerous: 2 (40.0%)
- Potentially dangerous dams include:
--- 2 in poor condition

#14. Bedford County
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- Total high-hazard dams: 5
- Number potentially dangerous: 2 (40.0%)
- Potentially dangerous dams include:
--- 2 condition withheld

#13. Huntingdon County
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- Total high-hazard dams: 5
- Number potentially dangerous: 2 (40.0%)
- Potentially dangerous dams include:
--- 1 in poor condition
--- 1 condition withheld

#12. Elk County
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- Total high-hazard dams: 2
- Number potentially dangerous: 1 (50.0%)
- Potentially dangerous dams include:
--- 1 condition withheld

#11. Northumberland County
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- Total high-hazard dams: 2
- Number potentially dangerous: 1 (50.0%)
- Potentially dangerous dams include:
--- 1 in poor condition

#10. Cameron County
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- Total high-hazard dams: 4
- Number potentially dangerous: 2 (50.0%)
- Potentially dangerous dams include:
--- 2 condition withheld

#9. Armstrong County
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- Total high-hazard dams: 6
- Number potentially dangerous: 3 (50.0%)
- Potentially dangerous dams include:
--- 3 in poor condition

#8. Adams County
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- Total high-hazard dams: 15
- Number potentially dangerous: 8 (53.3%)
- Potentially dangerous dams include:
--- 1 in poor condition
--- 7 condition withheld

#7. Tioga County
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- Total high-hazard dams: 11
- Number potentially dangerous: 6 (54.5%)
- Potentially dangerous dams include:
--- 4 in poor condition
--- 2 condition withheld

#6. Centre County
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- Total high-hazard dams: 7
- Number potentially dangerous: 4 (57.1%)
- Potentially dangerous dams include:
--- 3 in poor condition
--- 1 condition withheld

#5. Erie County
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- Total high-hazard dams: 7
- Number potentially dangerous: 4 (57.1%)
- Potentially dangerous dams include:
--- 4 in poor condition

#4. Lycoming County
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- Total high-hazard dams: 3
- Number potentially dangerous: 2 (66.7%)
- Potentially dangerous dams include:
--- 1 in poor condition
--- 1 condition withheld

#3. Warren County
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- Total high-hazard dams: 1
- Number potentially dangerous: 1 (100.0%)
- Potentially dangerous dams include:
--- 1 condition withheld

#2. Forest County
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- Total high-hazard dams: 4
- Number potentially dangerous: 4 (100.0%)
- Potentially dangerous dams include:
--- 1 posing immediate threat
--- 2 in poor condition
--- 1 condition withheld

This story features data reporting by Paxtyn Merten, writing by Dom DiFurio, and is part of a series utilizing data automation across 50 states.

#1. Clinton County
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