Dams in Merrimack County, New Hampshire
89Total Dams
18High Hazard
20Significant
Dam Safety in Merrimack County, New Hampshire
Merrimack County has 89 dams tracked in the National Inventory of Dams. Of these, 18 are classified as high hazard — meaning failure would probably cause loss of human life. Another 20 carry a significant hazard classification. Currently, 17 dams have a condition assessment of poor or unsatisfactory.
The average dam in Merrimack County is 107 years old. The most common purpose is recreation. The tallest dam is Franklin Falls Dam at 116 ft.
Explore more: Oldest dams in New Hampshire · Tallest dams · High risk dams · Largest reservoirs
| Dam | Hazard | Condition | Height (ft) | Purpose | Year |
|---|---|---|---|---|---|
| Franklin Falls Dam | High | Not Available | 116 | Flood Risk Reduction | 1943 |
| Hopkinton Dam - Dike H-2 | High | Not Available | 77 | Flood Risk Reduction | 1962 |
| Blackwater Dam | High | Not Available | 75 | Flood Risk Reduction | 1941 |
| Hopkinton Dam | High | Not Available | 71 | Flood Risk Reduction | 1962 |
| Hopkinton Dam - Dike H-3 | High | Not Available | 66 | Flood Risk Reduction | 1962 |
| Blackwater Dam - Little Hill Dike | High | Not Available | 38 | Flood Risk Reduction | 1941 |
| China Mill Dam | High | Fair | 29 | Hydroelectric | 1860 |
| Pittsfield Mill Dam | High | Poor | 21 | Recreation | 1920 |
| Berry Pond Dam | High | Satisfactory | 18 | Water Supply | 1884 |
| Blackwater Dam - Dodge Estate Dike | High | Not Available | 18 | Flood Risk Reduction | 1941 |
| Sanborn Pond Grist Mill Dam | High | Fair | 16 | Other | 1830 |
| Turkey Pond Dam | High | Satisfactory | 15 | Recreation | 1958 |
| Whites Pond Dam And Dike | High | Satisfactory | 15 | Recreation | 1890 |
| Webster Lake Dam | High | Satisfactory | 14 | Recreation | 1873 |
| Sanborn Sawmill Dam | High | Satisfactory | 13 | Other | 1830 |
| Northwood Lake Dam | High | Poor | 13 | Recreation | 1926 |
| Pleasant Lake Dam | High | Satisfactory | 13 | Recreation | 1850 |
| Penacook Lake Dam | High | Poor | 9 | Water Supply | 1873 |
| Chadwick Meadows Wildlife Ref Dam | Significant | Fair | 47 | Recreation | 1970 |
| Eastman Falls | Significant | Satisfactory | 43 | Hydroelectric | 1937 |
| Campus Drive Dam | Significant | Fair | 26 | Flood Risk Reduction | 2006 |
| Mount Sunapee Sewage Lagoon Dam | Significant | Satisfactory | 22 | Other | 1973 |
| Webster | Significant | Satisfactory | 22 | Hydroelectric | 1917 |
| Stevens Mill | Significant | Satisfactory | 22 | Hydroelectric | 1930 |
| Franklin Falls Hydro Dam 2 | Significant | Not Rated | 20 | Hydroelectric | 1888 |
| Bradley Lake Dam | Significant | Satisfactory | 19 | Recreation | 1952 |
| Pittsfield Sewage Lagoon Dam | Significant | Satisfactory | 18 | Other | 1979 |
| Hopkinton Sewage Lagoon Dam | Significant | Satisfactory | 18 | Other | 1983 |
| Chase Pond Dam | Significant | Satisfactory | 17 | Recreation | 1915 |
| Todd Lake Dam | Significant | Poor | 17 | Recreation | 1858 |
| Bog Pond Dam | Significant | Satisfactory | 17 | Recreation | 1870 |
| Lyford Pond Dam | Significant | Poor | 15 | Recreation | 1840 |
| Runaway Pond East Dam | Significant | Poor | 15 | Recreation | 1814 |
| Webster Valve Co Dam | Significant | Poor | 15 | Other | 1901 |
| Hoague - Sprague | Significant | Satisfactory | 14 | Hydroelectric | 1906 |
| Highland Lake Dam | Significant | Fair | 10 | Recreation | 1935 |
| Dube Pond Dam | Significant | Poor | 8 | Recreation | 1966 |
| Transfer Station Lagoons Dam | Significant | Unsatisfactory | 0 | Other | |
| Ragged Mountain Snow Pond Dam | Low | Fair | 49 | Fish and Wildlife Pond | 1988 |
| Pembroke | Low | Satisfactory | 26 | Hydroelectric | 1891 |
| Sheep Davis Road Dam | Low | Fair | 24 | Flood Risk Reduction | 1990 |
| Penacook Upper Falls | Low | Satisfactory | 23 | Hydroelectric | 1987 |
| Flagpole Pond Dam | Low | Fair | 21 | Recreation | 1967 |
| Garvins Falls | Low | Satisfactory | 18 | Hydroelectric | 1901 |
| Giles Pond | Low | Satisfactory | 18 | Hydroelectric | 1904 |
| Briar Pipe | Low | Satisfactory | 17 | Hydroelectric | 1936 |
| Goldfish Pond Dam | Low | Fair | 16 | Recreation | 1974 |
| Flagpole Pond Dike | Low | Fair | 15 | Recreation | 1967 |
| Deer Meadow Pond Dam | Low | Fair | 15 | Recreation | 1938 |
| Penacook Lower Falls Diversion | Low | Satisfactory | 15 | Hydroelectric | 1982 |
| Allied Leather Auxiliary | Low | Satisfactory | 15 | Hydroelectric | 1982 |
| Fountain Pond Center Dam | Low | Not Rated | 14 | Recreation | 1800 |
| Catamount Pond Dam | Low | Fair | 14 | Recreation | 1938 |
| Hargate Dam | Low | Satisfactory | 14 | Recreation | 1835 |
| Pillsbury Lake Dam | Low | Satisfactory | 13 | Recreation | 1964 |
| Fifield Farm Pond Dam | Low | Fair | 13 | Fish and Wildlife Pond | 1966 |
| Hall Mountain Marsh Dam | Low | Fair | 13 | Recreation | 1945 |
| New Pond Dam | Low | Not Rated | 13 | Recreation | 1885 |
| Tannery Pond Dam | Low | Satisfactory | 12 | Recreation | 1850 |
| Morey Pond Dam | Low | Fair | 12 | Recreation | |
| Stark Pond Dam | Low | Satisfactory | 12 | Fish and Wildlife Pond | 1760 |
| Loch Lyndon Reservoir Dam | Low | Not Rated | 12 | Recreation | 1901 |
| Goose Pond Dam | Low | Not Rated | 12 | Recreation | 1920 |
| Cascade Brook Dam | Low | Fair | 11 | Recreation | 1955 |
| Knowles Pond Dam | Low | Satisfactory | 11 | Recreation | 1935 |
| Hooksett | Low | Satisfactory | 11 | Hydroelectric | 1927 |
| Morrill Mill Pond Dam | Low | Poor | 11 | Fish and Wildlife Pond | 1800 |
| Emery Road Dam | Low | Fair | 10 | Fish and Wildlife Pond | 1910 |
| Hayes Marsh Dam | Low | Fair | 10 | Recreation | 1951 |
| Cole Pond Dam | Low | Satisfactory | 10 | Recreation | 1973 |
| York | Low | Satisfactory | 10 | Hydroelectric | 1967 |
| Hopkinton | Low | Satisfactory | 10 | Hydroelectric | 1890 |
| Cass Pond Dam | Low | Poor | 10 | Recreation | |
| Blaisdell Lake Dam | Low | Poor | 9 | Recreation | 1916 |
| Knight Meadow Pond Dam | Low | Fair | 9 | Recreation | 1966 |
| Grassy Pond Dam | Low | Fair | 9 | Recreation | 1836 |
| Hoit Road Marsh Dam | Low | Poor | 9 | Recreation | 1968 |
| Kimball Pond Dam | Low | Satisfactory | 8 | Recreation | 1850 |
| Bear Pond Dam | Low | Satisfactory | 8 | Water Supply | 1932 |
| Belanger Recreation Pond Dam | Low | Satisfactory | 8 | Recreation | 1992 |
| Recreation Pond Dam | Low | Fair | 8 | Recreation | 1950 |
| Flintlock Estates Fire Pond Dam | Low | Fair | 8 | Fire Protection, Stock, Or Small Fish Pond | 1987 |
| Putney Meadow Pond Dam | Low | Poor | 8 | Recreation | 1800 |
| Turtle Pond Dam | Low | Poor | 8 | Recreation | 1932 |
| Winnipocket Lake Dam | Low | Poor | 7 | Recreation | 1944 |
| Bear Hill Pond Dam | Low | Fair | 7 | Recreation | 1885 |
| Kimball Lake Dam | Low | Poor | 7 | Recreation | 1930 |
| Huckins Mill Dam | Undetermined | Not Rated | 13 | Recreation | 1830 |
| Walker Pond Dam | Undetermined | Not Rated | 6 | Recreation | 1900 |