Risky reservoirs: New Hampshire counties where aging dams pose the greatest threat

Catharine Britt // Shutterstock

- Total high-hazard dams: 7
- Number potentially dangerous: 2 (28.6%)
- Potentially dangerous dams include:
--- 2 in poor condition

#10. Sullivan County
Canva

- Total high-hazard dams: 13
- Number potentially dangerous: 4 (30.8%)
- Potentially dangerous dams include:
--- 4 in poor condition

#9. Strafford County
Canva

- Total high-hazard dams: 36
- Number potentially dangerous: 12 (33.3%)
- Potentially dangerous dams include:
--- 7 in poor condition
--- 1 not rated
--- 4 condition withheld

#8. Hillsborough County
Josh Conover // Shutterstock

- Total high-hazard dams: 25
- Number potentially dangerous: 9 (36.0%)
- Potentially dangerous dams include:
--- 9 in poor condition

#7. Grafton County
Canva

- Total high-hazard dams: 10
- Number potentially dangerous: 4 (40.0%)
- Potentially dangerous dams include:
--- 3 in poor condition
--- 1 not rated

#6. Coos County
Edward Fileding // Shutterstock

- Total high-hazard dams: 22
- Number potentially dangerous: 9 (40.9%)
- Potentially dangerous dams include:
--- 7 in poor condition
--- 2 condition withheld

#5. Cheshire County
Wangkun Jia // Shutterstock

- Total high-hazard dams: 11
- Number potentially dangerous: 5 (45.5%)
- Potentially dangerous dams include:
--- 5 in poor condition

#4. Rockingham County
Canva

- Total high-hazard dams: 18
- Number potentially dangerous: 10 (55.6%)
- Potentially dangerous dams include:
--- 3 in poor condition
--- 7 condition withheld

#3. Merrimack County
NEKVT // Shutterstock

- Total high-hazard dams: 10
- Number potentially dangerous: 7 (70.0%)
- Potentially dangerous dams include:
--- 7 in poor condition

#2. Carroll County
Canva

- Total high-hazard dams: 8
- Number potentially dangerous: 8 (100.0%)
- Potentially dangerous dams include:
--- 8 in poor condition

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. Belknap County
Wangkun Jia // Shutterstock