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High Risk Dams in New Hampshire

New Hampshire has 57 high hazard dams with a condition assessment of poor or unsatisfactory. These are dams where failure would probably cause loss of human life and where recognized safety deficiencies have been identified.

Of the 162 high hazard dams in New Hampshire, 57 (35%) have concerning condition ratings — 57 rated poor and 0 rated unsatisfactory.

Condition scale, best to worst
  1. Satisfactory No existing or potential safety deficiencies recognized; acceptable performance expected under all loading conditions.
  2. Fair No deficiencies under normal operating conditions; a rare flood or earthquake could create one.
  3. Poor A safety deficiency is recognized under normal operating conditions; remedial action is necessary.
  4. Unsatisfactory Worst rating. The dam is considered unsafe; a deficiency requires immediate or emergency remedial action.

"Not rated" means no assessment is on file in the National Inventory of Dams.

DamCountyHeight (ft)ConditionLast inspectedPurposeYear
Baker River Site 6a DamGrafton68Poor05/05/20224 yrs agoFlood Risk Reduction1975
Baker River Site 5 DamGrafton53Poor05/05/20224 yrs agoFlood Risk Reduction1967
Jackman Reservoir DamHillsborough43Poor10/03/20224 yrs agoHydroelectric1926
Lake Gloriette DikeCoos34Poor10/18/20223 yrs agoRecreation1913
Weare Reservoir DamHillsborough34Poor04/06/20224 yrs agoRecreation1913
Pisgah Reservoir DamCheshire33Poor10/06/20224 yrs agoRecreation1870
Lake Gloriette DamCoos33Poor10/18/20223 yrs agoRecreation1913
Mendums Pond DamRockingham31Poor08/31/20215 yrs agoRecreation1840
Goose Pond DamGrafton31Poor10/31/20223 yrs agoRecreation1918
Goffstown Upper Reservoir DamHillsborough31Poor05/17/20224 yrs agoWater Supply1934
Kelley's Falls DamHillsborough31Poor05/24/20224 yrs agoHydroelectric1916
Pawtuckaway Lake Dollof DamRockingham28Poor08/31/20215 yrs agoRecreation1842
Bowers DamHillsborough25Poor09/27/20224 yrs agoWater Supply1884
Bow Lake DamStrafford24Poor10/27/20223 yrs agoRecreation1832
New Wilton Reservoir DamHillsborough24Poor10/24/20232 yrs agoRecreation1931
Baker River Site 11 DamGrafton24Poor05/05/20224 yrs agoFlood Risk Reduction1971
Merrymeeting Lake DamStrafford22Poor08/10/20215 yrs agoRecreation1924
Rivermill Mascoma Hydro DamGrafton22Poor08/08/20188 yrs agoHydroelectric1920
Jones DamStrafford21Poor08/10/20215 yrs agoRecreation1924
Pittsfield Mill DamMerrimack21Poor12/09/20223 yrs agoRecreation1920
Millville Lake DamRockingham20Poor10/24/20223 yrs agoRecreation1917
Walpole Reservoir DamCheshire20Poor09/23/20215 yrs agoWater Supply1901
Dells Pond Outlet DamGrafton20Poor08/17/20224 yrs agoRecreation1935
Sawyer Lake DamBelknap19Poor05/11/20215 yrs agoRecreation1916
Milton Three Ponds DamStrafford19Poor11/08/20214 yrs agoRecreation1824
Cheshire Mills Lower DamCheshire18Poor08/25/20224 yrs agoHydroelectric1848
Mascoma Lake DamGrafton18Poor10/31/20223 yrs agoRecreation1881
Upper Wilson Pond DamCheshire17Poor03/23/20215 yrs agoRecreation1910
Sargent Lake DamBelknap17Poor11/17/20214 yrs agoRecreation1870
Sunset Lake DamBelknap17Poor05/04/20206 yrs agoRecreation1860
Crystal Lake DamBelknap16Poor09/26/20197 yrs agoRecreation1958
Barnstead Parade DamBelknap16Poor07/14/20215 yrs agoRecreation1830
Stratford Bog Pond DamCoos16Poor10/18/20223 yrs agoRecreation1934
Suncook Lake DamBelknap16Poor07/14/20215 yrs agoRecreation1882
Alton Power DamBelknap16Poor04/26/20224 yrs agoRecreation1923
Grist Mill Pond DamGrafton16Poor06/16/20215 yrs agoHydroelectric1924
Pickpocket DamRockingham15Poor09/15/20224 yrs agoRecreation1920
Exeter Reservoir DamRockingham15Poor06/02/20215 yrs agoWater Supply1886
Great East Lake DamCarroll15Poor04/25/20224 yrs agoRecreation1825
Loon Lake DamSullivan15Poor10/07/20215 yrs agoRecreation1920
Lake Waukewan DamBelknap15Poor11/16/20214 yrs agoRecreation1880
Horn Pond DamCarroll14Poor04/25/20224 yrs agoRecreation1930
Beech River Mill DamCarroll14Poor09/26/20224 yrs agoHydroelectric1851
Warren Lake DamCheshire13Poor11/04/20214 yrs agoRecreation1771
Lower Damon Reservoir DamCheshire13Poor10/20/20214 yrs agoRecreation1832
Ashuelot Pond DamSullivan13Poor07/12/20224 yrs agoRecreation1872
Purity Lake DamCarroll13Poor09/26/20224 yrs agoRecreation1750
Northwood Lake DamMerrimack13Poor08/31/20215 yrs agoRecreation1926
Gregg Lake DamHillsborough12Poor09/01/20215 yrs agoRecreation1908
Newfound Lake DamGrafton12Poor09/21/20224 yrs agoRecreation1840
Lovell Lake DamCarroll12Poor04/25/20224 yrs agoRecreation1910
Highland Lake DamCheshire11Poor11/08/20223 yrs agoRecreation1911
Gumpas Pond DamHillsborough10Poor10/24/20223 yrs agoRecreation1900
Upper Kimball Pond DamCarroll10Poor10/18/20223 yrs agoRecreation1800
Penacook Lake DamMerrimack9Poor10/25/20223 yrs agoWater Supply1873
Dorrs Pond DamHillsborough9Poor09/22/20224 yrs agoRecreation1934
Pierce Pond DamHillsborough8Poor04/13/20215 yrs agoRecreation1700

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