Iowa Dams
4,124 dams tracked by the National Inventory of Dams
Total Dams
4,124
High Hazard
91
2.2%
Poor / Unsatisfactory
25
Average Age
46 yrs
Hazard Classification
High91 (2.2%)
Significant274 (6.6%)
Low3,759 (91.1%)
Condition Assessment
Satisfactory259 (6.3%)
Fair81 (2.0%)
Poor / Unsatisfactory25 (0.6%)
Not Rated3,759 (91.1%)
Federal
25
State
141
Local
1,938
Private
2,014
Tallest Dams
- Coralville Dam132 ft
- Saylorville Dam125 ft
- County Basin Dam104 ft
- Rathbun Dam100 ft
- Brushy Creek Dam100 ft
High Hazard Dams
- Coralville DamHigh
- Saylorville DamHigh
- Rathbun DamHigh
- Brushy Creek DamHigh
- Big Creek Barrier DamHigh
Poor Condition Dams
All Dams in Iowa
Showing 1501–1525 of 4,124
| Dam Name | Height (ft) | Year | Hazard | Condition |
|---|---|---|---|---|
| Olson Dam Cerro Gordo County | 21 | 1972 | Low | Not Rated |
| Olson Dam Story County | 24 | 1969 | Low | Poor |
| Olson Dam Decatur County | 25 | 1964 | Low | Not Rated |
| Olson/Cretsinger Dam Guthrie County | 31 | 1967 | Low | Not Rated |
| Olsen Dam Harrison County | 52 | 1961 | Low | Not Rated |
| Olmstead Dam Polk County | 27 | 1966 | Low | Not Rated |
| Olmschied Dam Plymouth County | 25 | 1974 | Low | Not Rated |
| Old Reservoir Dam Ringgold County | 25 | 1920 | Low | Not Rated |
| Old Quarry Lake Dam Cerro Gordo County | 13 | 1977 | Significant | Fair |
| Ohnemus Farms Dam Warren County | 29 | 1990 | Low | Not Rated |
| Ohnemus Dam Warren County | 25 | 1965 | Low | Not Rated |
| Oen Dam Wayne County | 28 | 2008 | Low | Not Rated |
| Odoherty Dam Montgomery County | 19 | 2024 | Low | Not Rated |
| Odetta Lake Dam Scott County | 20 | 1964 | Low | Not Rated |
| O Brien Dam Guthrie County | 33 | 1989 | Low | Not Rated |
| Oberreuter Dam Woodbury County | 28 | 1973 | Low | Not Rated |
| Oakridge Lake Estates Dam Johnson County | 42 | 1977 | Low | Not Rated |
| Oaknoll Dam Johnson County | 25 | 1994 | High | Fair |
| Oakland Mills Dam Henry County | 10 | 1910 | Low | Satisfactory |
| Oakland Acres Dam Jasper County | 21 | 1994 | Low | Not Rated |
| Oakland Acres Dam Jasper County | 34 | 1972 | Low | Not Rated |
| Oak Lake Dam Kossuth County | 50 | 1971 | Significant | Satisfactory |
| Oak Hill Plantation Dam Dallas County | 32 | 2004 | Significant | Satisfactory |
| Oak Grove Park Dam Sioux County | 26 | 1977 | Low | Not Rated |
| Nyswonger Dam Warren County | 30 | 1970 | Low | Not Rated |
Data sourced from the National Inventory of Dams (NID). Hazard classification reflects potential consequences of failure, not the likelihood of failure.