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High Risk Dams in New Jersey

New Jersey has 56 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 232 high hazard dams in New Jersey, 56 (24%) have concerning condition ratings — 56 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
Round Valley South DamHunterdon178Poor10/01/20206 yrs agoWater Supply1961
Round Valley North DamHunterdon135Poor10/01/20206 yrs agoWater Supply1961
Spruce Run Reservoir DamHunterdon93Poor09/25/20242 yrs agoWater Supply1964
Round Valley DikeHunterdon80Poor09/23/20197 yrs agoWater Supply1961
Oak Ridge Reservoir DamPassaic60Poor10/30/20241 yr agoWater Supply1892
West Branch Reservoir DamSomerset39Poor11/06/20241 yr agoRecreation1930
Warren Mill DamHunterdon38Poor01/04/20242 yrs agoWater Supply1916
Hackettstown Res. DamMorris38Poor03/28/20224 yrs agoWater Supply
Assunpink #18 DamMonmouth38Poor10/03/20242 yrs agoFlood Risk Reduction
Union Lake DamCumberland35Poor10/08/20242 yrs agoRecreation1869
Cupsaw Lake DamPassaic35Poor10/24/20232 yrs agoRecreation1930
Powder Mill Pond DamMorris35Poor03/30/20233 yrs agoRecreation
Macopin Reservoir DamMorris34Poor10/18/20241 yr agoWater Supply1892
Pleasant Valley Lake DamSussex31Poor11/10/20232 yrs agoRecreation
Lake Lenape DamAtlantic29Poor05/17/20224 yrs agoRecreation1879
Stony Brook Water Shed #7 (hunt Lake) DamMercer28Poor08/10/20233 yrs agoIrrigation1959
Lionshead Lake DamPassaic27Poor03/20/20242 yrs agoRecreation1939
Jaqui Mill DamMorris27Poor03/19/20242 yrs agoFlood Risk Reduction1920
River Wall DamPassaic26Poor11/01/20241 yr agoRecreation1961
Stump Pond DamSussex25Poor11/10/20232 yrs agoRecreation
Assunpink #4 DamMonmouth24Poor10/03/20242 yrs agoFlood Risk Reduction
Longwood Lake DamMorris22Poor03/21/20242 yrs agoRecreation1898
Lake Arcadia Dam #1Passaic22Poor07/13/20233 yrs agoRecreation1926
High Crest Lake DamPassaic22Poor12/12/20232 yrs agoRecreation1952
Lake Conway DamSussex21Poor12/20/20241 yr agoRecreation1958
Lake Vreeland DamBergen20Poor08/18/20224 yrs agoRecreation1917
Wadsworth Lake DamGloucester20Poor03/20/20206 yrs agoRecreation1926
Matawan Lake DamMonmouth20Poor03/29/20233 yrs agoRecreation1923
Assunpink #8 DamMercer20Poor05/03/20233 yrs agoWater Supply
Elkinton Pond DamSalem20Poor07/26/20242 yrs agoRecreation1923
Birchwood Lake DamMorris20Poor12/06/20241 yr agoRecreation
Prospertown DamOcean19Poor10/23/20241 yr agoFlood Risk Reduction1966
Atsion Lake DamBurlington19Poor08/01/20233 yrs agoRecreation1930
Lake Estling DamMorris19Poor03/30/20233 yrs agoRecreation1870
Youngs Pond DamWarren18Poor09/18/20242 yrs agoRecreation1972
Centennial Lake DamBurlington18Poor01/04/20242 yrs agoRecreation
Cranberry Lake DamSussex18Poor08/29/20242 yrs agoRecreation
Valhalla Lake DamMorris18Poor07/07/20224 yrs agoRecreation1910
Lake Hopatcong DamMorris17Poor08/28/20242 yrs agoFlood Risk Reduction1925
Greenwood Lake DamPassaic17Poor10/10/20241 yr agoRecreation1928
Camp Beisler DamHunterdon17Poor04/09/20197 yrs agoRecreation1971
Saxton Falls DamMorris16Poor09/24/20242 yrs agoRecreation1927
Lake Lefferts DamMonmouth16Poor11/27/20241 yr agoRecreation1928
West Milford Lake DamPassaic16Poor01/15/20206 yrs agoRecreation1929
Lake Winona DamMorris15Poor03/26/20251 yr agoRecreation1950
Lake Panorama DikeSussex15Poor04/20/20233 yrs agoRecreation1987
New Jersey No Name # 40 DamPassaic15Poor09/19/20242 yrs agoRecreation
Ramapo Lake DamBergen13Poor09/19/20242 yrs agoRecreation
Mountain Creek Lake DamSussex12Poor03/11/20251 yr agoRecreation1984
Lake DenmarkMorris12Poor07/24/20188 yrs agoWater Supply1904
Diversion DamSussex8Poor11/07/20241 yr agoWater Supply1959
Memorial Park Pond DamSomerset8Poor12/15/20232 yrs agoRecreation
Sunset Lake DamMorris8Poor10/31/20241 yr agoRecreation1914
Upper Mount Glen Lake DamPassaic8Poor11/16/20232 yrs agoRecreation1927
Core Wall DamPassaic7Poor08/31/20233 yrs agoRecreation
West Shore Trail DamSussex0Poor01/15/20206 yrs ago

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