65Total Dams
19High Hazard
11Significant
Dam Safety in St. Lawrence County, New York
St. Lawrence County has 65 dams tracked in the National Inventory of Dams. Of these, 19 are classified as high hazard — meaning failure would probably cause loss of human life. Another 11 carry a significant hazard classification. Currently, 1 dam has a condition assessment of poor or unsatisfactory.
The average dam in St. Lawrence County is 89 years old. The most common purpose is hydroelectric. The tallest dam is Long Sault at 132 ft.
Explore more: Oldest dams in New York · Tallest dams · High risk dams · Largest reservoirs
| Dam | Hazard | Condition | Height (ft) | Purpose | Year |
|---|---|---|---|---|---|
| Long Sault | High | Satisfactory | 132 | Hydroelectric | 1958 |
| Massena Intake | High | Satisfactory | 118 | Hydroelectric | 1958 |
| Rainbow | High | Satisfactory | 82 | Hydroelectric | 1956 |
| Blake | High | Satisfactory | 80 | Hydroelectric | 1957 |
| Flat Rock | High | Satisfactory | 72 | Hydroelectric | 1925 |
| Browns Falls | High | Satisfactory | 70 | Hydroelectric | 1922 |
| Five Falls | High | Satisfactory | 53 | Hydroelectric | 1954 |
| Newton Falls Upper | High | Satisfactory | 50 | Hydroelectric | 1927 |
| South Colton | High | Satisfactory | 42 | Hydroelectric | 1954 |
| Higley | High | Satisfactory | 37 | Hydroelectric | 1925 |
| Allens Falls | High | Satisfactory | 37 | Hydroelectric | 1991 |
| Norfolk Dam | High | Not assessed | 29 | Hydroelectric | 1965 |
| Colton | High | Satisfactory | 29 | Hydroelectric | 1919 |
| Long Sault North | High | Satisfactory | 25 | Hydroelectric | 1958 |
| Cranberry Lake Dam | High | Satisfactory | 24 | Recreation | 1917 |
| Norwood | High | Fair | 24 | Hydroelectric | 1928 |
| Piercefield | High | Satisfactory | 22 | Hydroelectric | 1914 |
| East Norfolk | High | Satisfactory | 16 | Hydroelectric | 1928 |
| Ogdensburg | High | Satisfactory | 12 | Hydroelectric | 1910 |
| Iroquois | Significant | Satisfactory | 72 | Hydroelectric | 1958 |
| South Edwards | Significant | Satisfactory | 53 | Hydroelectric | 1914 |
| Benson Mines Little River Dam | Significant | Poor | 44 | Irrigation | 1948 |
| Heuvelton | Significant | Satisfactory | 35 | Hydroelectric | 1923 |
| Stark Falls Dike a | Significant | Satisfactory | 22 | Hydroelectric | 1957 |
| Carry Falls Dike a | Significant | Satisfactory | 17 | Hydroelectric | 1953 |
| Hailsboro Mill #3 Dam | Significant | Not assessed | 16 | Hydroelectric | 1910 |
| Hailesboro Mill #6 Dam | Significant | Not assessed | 14 | Hydroelectric | |
| Hailesboro #4 Plant Dam | Significant | Not assessed | 12 | Hydroelectric | 1912 |
| Niagara Mohawk Power Dam | Significant | Not assessed | 11 | Hydroelectric | 1916 |
| Gouverneur | Significant | Satisfactory | 7 | Hydroelectric | 1925 |
| Chaumont Swamp Dam | Low | Not assessed | 100 | Irrigation | 1954 |
| Benson Mines Plant Dam | Low | Not assessed | 38 | Irrigation | |
| Massena Diversion Dam | Low | Not assessed | 35 | Other | 1912 |
| Newton Falls Stabilization Pond #4 Dam | Low | Not assessed | 35 | Other | 1965 |
| Sugar Island | Low | Satisfactory | 35 | Hydroelectric | 1925 |
| Hannawa | Low | Satisfactory | 34 | Hydroelectric | 1902 |
| Hollow Dam | Low | Satisfactory | 31 | Hydroelectric | 1987 |
| Bog River Dam | Low | Not assessed | 28 | Recreation | 1904 |
| Pyrites Intake | Low | Satisfactory | 27 | Hydroelectric | 1908 |
| Emeryville | Low | Satisfactory | 25 | Hydroelectric | 1959 |
| Fowler #7 - Dam No. 1 | Low | Satisfactory | 25 | Hydroelectric | 1928 |
| Newton Falls Lower | Low | Satisfactory | 25 | Hydroelectric | 1927 |
| Eel Weir | Low | Satisfactory | 23 | Hydroelectric | 1928 |
| Newton Falls Stabilization Pond #3 Dam | Low | Not assessed | 22 | Other | 1965 |
| Lows Lake Dam | Low | Not assessed | 21 | Recreation | 1903 |
| Unionville | Low | Satisfactory | 20 | Hydroelectric | 1907 |
| Parishville | Low | Satisfactory | 19 | Hydroelectric | 1925 |
| Hewittville | Low | Satisfactory | 18 | Hydroelectric | 1870 |
| Raymondville | Low | Satisfactory | 17 | Hydroelectric | 1928 |
| Chapman Dam | Low | Not assessed | 16 | Recreation | 1971 |
| Sissonville | Low | Satisfactory | 16 | Hydroelectric | 1990 |
| Weller Pond Dam | Low | Not assessed | 15 | Fire Protection, Stock, Or Small Fish Pond | |
| Grasse River Dam | Low | Not assessed | 13 | Flood Risk Reduction | 1881 |
| Talcville | Low | Satisfactory | 13 | Hydroelectric | 1987 |
| Mill Dam | Low | Not assessed | 12 | Other | 1916 |
| Upper & Lower Lakes Dam #1 | Low | Not assessed | 12 | Fish and Wildlife Pond | 1970 |
| Yaleville | Low | Satisfactory | 12 | Hydroelectric | 1914 |
| Smithline Wrp Dam | Low | Not assessed | 11 | Fish and Wildlife Pond | 1998 |
| Redwater Brook Dam | Low | Not assessed | 11 | Other | |
| Potsdam - West Dam | Low | Satisfactory | 11 | Hydroelectric | 1990 |
| Eli Sochia Dam | Low | Not assessed | 10 | Recreation | |
| L Hance Wetland Reserve Dam | Low | Not assessed | 10 | Fish and Wildlife Pond | 2000 |
| Massena Village Dam | Low | Not assessed | 8 | Recreation | 1860 |
| Twin Lakes Dam | Low | Not assessed | 7 | Other | |
| Potsdam - East Dam | Low | Satisfactory | 7 | Hydroelectric | 1903 |