Dams in Iowa
4,046
Total Dams
91
High Hazard
2.25%
% High Hazard
46.6 yrs
Average Age
Counties
| County | Dams | High Hazard | % High | Avg Age |
|---|---|---|---|---|
| Woodbury | 312 | 11 | 3.53% | 55.0 yrs |
| Polk | 76 | 10 | 13.16% | 45.5 yrs |
| Johnson | 33 | 6 | 18.18% | 49.6 yrs |
| Black Hawk | 11 | 5 | 45.45% | 49.0 yrs |
| Wapello | 54 | 5 | 9.26% | 33.2 yrs |
| Plymouth | 75 | 4 | 5.33% | 55.3 yrs |
| Clinton | 13 | 4 | 30.77% | 44.2 yrs |
| Clayton | 10 | 3 | 30.00% | 61.4 yrs |
| Story | 34 | 3 | 8.82% | 52.3 yrs |
| Dallas | 66 | 3 | 4.55% | 43.2 yrs |
| Union | 127 | 2 | 1.57% | 41.4 yrs |
| Crawford | 145 | 2 | 1.38% | 49.8 yrs |
| Clarke | 59 | 2 | 3.39% | 38.3 yrs |
| Des Moines | 33 | 2 | 6.06% | 56.5 yrs |
| Poweshiek | 33 | 2 | 6.06% | 40.3 yrs |
| Scott | 22 | 2 | 9.09% | 49.5 yrs |
| Pottawattamie | 85 | 2 | 2.35% | 49.3 yrs |
| Linn | 18 | 2 | 11.11% | 42.8 yrs |
| Audubon | 83 | 2 | 2.41% | 47.6 yrs |
| Dubuque | 12 | 1 | 8.33% | 33.3 yrs |
| Adams | 57 | 1 | 1.75% | 54.2 yrs |
| Carroll | 11 | 1 | 9.09% | 50.2 yrs |
| Buena Vista | 13 | 1 | 7.69% | 47.2 yrs |
| Iowa | 19 | 1 | 5.26% | 45.3 yrs |
| Warren | 103 | 1 | 0.97% | 43.2 yrs |
| Sioux | 7 | 1 | 14.29% | 39.4 yrs |
| Webster | 15 | 1 | 6.67% | 48.7 yrs |
| Fremont | 67 | 1 | 1.49% | 54.0 yrs |
| Jackson | 11 | 1 | 9.09% | 47.5 yrs |
| Franklin | 7 | 1 | 14.29% | 41.7 yrs |
| Lucas | 86 | 1 | 1.16% | 48.0 yrs |
| Madison | 80 | 1 | 1.25% | 43.2 yrs |
| Adair | 53 | 1 | 1.89% | 44.2 yrs |
| Appanoose | 95 | 1 | 1.05% | 38.9 yrs |
| Van Buren | 45 | 1 | 2.22% | 36.3 yrs |
| Harrison | 100 | 1 | 1.00% | 45.5 yrs |
| Decatur | 90 | 1 | 1.11% | 38.8 yrs |
| Mills | 78 | 1 | 1.28% | 53.4 yrs |
| Dickinson | 7 | 0 | 0.00% | 38.9 yrs |
| Floyd | 6 | 0 | 0.00% | 116.8 yrs |
| Buchanan | 5 | 0 | 0.00% | 100.0 yrs |
| Fayette | 7 | 0 | 0.00% | 69.7 yrs |
| Boone | 16 | 0 | 0.00% | 58.0 yrs |
| Clay | 5 | 0 | 0.00% | 36.5 yrs |
| Humboldt | 7 | 0 | 0.00% | 61.7 yrs |
| Wright | 3 | 0 | 0.00% | 24.0 yrs |
| Palo Alto | 3 | 0 | 0.00% | 42.7 yrs |
| Davis | 146 | 0 | 0.00% | 40.2 yrs |
| Cass | 77 | 0 | 0.00% | 43.7 yrs |
| Wayne | 77 | 0 | 0.00% | 40.2 yrs |
| Page | 29 | 0 | 0.00% | 46.2 yrs |
| Muscatine | 14 | 0 | 0.00% | 44.5 yrs |
| Butler | 7 | 0 | 0.00% | 62.1 yrs |
| Greene | 18 | 0 | 0.00% | 39.2 yrs |
| Chickasaw | 5 | 0 | 0.00% | 59.4 yrs |
| Monroe | 81 | 0 | 0.00% | 30.1 yrs |
| Ringgold | 164 | 0 | 0.00% | 25.6 yrs |
| Montgomery | 43 | 0 | 0.00% | 39.6 yrs |
| Monona | 199 | 0 | 0.00% | 60.5 yrs |
| Jefferson | 65 | 0 | 0.00% | 43.2 yrs |
| Shelby | 60 | 0 | 0.00% | 51.6 yrs |
| Cherokee | 53 | 0 | 0.00% | 52.7 yrs |
| Taylor | 64 | 0 | 0.00% | 50.4 yrs |
| Ida | 61 | 0 | 0.00% | 49.9 yrs |
| Mahaska | 37 | 0 | 0.00% | 49.8 yrs |
| Allamakee | 16 | 0 | 0.00% | 47.4 yrs |
| O'Brien | 13 | 0 | 0.00% | 55.1 yrs |
| Guthrie | 58 | 0 | 0.00% | 50.3 yrs |
| Jones | 9 | 0 | 0.00% | 64.7 yrs |
| Winneshiek | 18 | 0 | 0.00% | 36.9 yrs |
| Lyon | 8 | 0 | 0.00% | 56.0 yrs |
| Tama | 31 | 0 | 0.00% | 48.8 yrs |
| Louisa | 24 | 0 | 0.00% | 37.5 yrs |
| Mitchell | 4 | 0 | 0.00% | 106.3 yrs |
| Emmet | 5 | 0 | 0.00% | 40.0 yrs |
| Washington | 54 | 0 | 0.00% | 39.5 yrs |
| Kossuth | 7 | 0 | 0.00% | 50.4 yrs |
| Keokuk | 27 | 0 | 0.00% | 44.4 yrs |
| Henry | 33 | 0 | 0.00% | 40.0 yrs |
| Pocahontas | 8 | 0 | 0.00% | 33.9 yrs |
| Delaware | 12 | 0 | 0.00% | 64.4 yrs |
| Hamilton | 3 | 0 | 0.00% | 49.7 yrs |
| Hardin | 20 | 0 | 0.00% | 56.8 yrs |
| Marshall | 19 | 0 | 0.00% | 50.4 yrs |
| Howard | 5 | 0 | 0.00% | 105.2 yrs |
| Hancock | 3 | 0 | 0.00% | 45.3 yrs |
| Benton | 12 | 0 | 0.00% | 48.0 yrs |
| Cerro Gordo | 10 | 0 | 0.00% | 51.6 yrs |
| Jasper | 51 | 0 | 0.00% | 49.7 yrs |
| Lee | 28 | 0 | 0.00% | 49.8 yrs |
| Marion | 45 | 0 | 0.00% | 44.1 yrs |
| Sac | 6 | 0 | 0.00% | 43.2 yrs |
| Worth | 7 | 0 | 0.00% | 50.2 yrs |
Purpose Breakdown
Tallest Dams in Iowa
| Dam Name | Height | County | Hazard |
|---|---|---|---|
| Saylorville Dam | 119 ft | Polk | High Hazard |
| Gibson North - Dredge Spoil Containment | 104 ft | Guthrie | Significant Hazard |
| Coralville Dam | 100 ft | Johnson | High Hazard |
| Brushy Creek Dam | 100 ft | Webster | High Hazard |
| Gibson South - Dredge Spoil Disposal | 95 ft | Guthrie | Significant Hazard |
| Big Creek Barrier Dam | 84 ft | Polk | High Hazard |
| Des Moines County Roadgrade Dam 18-70-2 | 84 ft | Des Moines | Low Hazard |
| North Pigeon Cr Watershed Site 11-1 | 81 ft | Pottawattamie | Low Hazard |
| Big Creek Diversion Dam | 80 ft | Polk | High Hazard |
| Maffitt Reservoir Dam | 79 ft | Dallas | High Hazard |