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High Risk Dams in Hawaii

Hawaii has 88 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 117 high hazard dams in Hawaii, 88 (75%) have concerning condition ratings — 75 rated poor and 13 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
Puu Lua ReservoirKauai110Unsatisfactory05/30/20242 yrs agoFish and Wildlife Pond1925
Wahiawa DamHonolulu98Poor11/10/20232 yrs agoIrrigation1906
Ku Tree ReservoirHonolulu90Unsatisfactory06/22/20224 yrs agoOther1925
Horner ReservoirMaui70Poor07/27/20242 yrs agoIrrigation1926
Mimino ReservoirKauai69Poor09/17/20242 yrs agoIrrigation1920
Waikoloi ReservoirKauai64Poor10/22/20241 yr agoIrrigation1958
Kahoma ReservoirMaui60Poor04/26/20251 yr agoIrrigation1918
Kahana Nui DamMaui58Poor04/17/20251 yr agoFlood Risk Reduction1984
Piwai ReservoirKauai56Poor05/06/20251 yr agoIrrigation1916
Kahakapao ReservoirsMaui54Poor05/15/20251 yr agoWater Supply1990
Kapaia ReservoirKauai53Poor02/11/20251 yr agoIrrigation1910
Wailuku Water Reservoir 10Maui52Unsatisfactory04/17/20251 yr agoIrrigation1951
Waimea 60 Mg ReservoirHawaii52Poor07/26/20251 yr agoIrrigation1957
Kaneha ReservoirKauai51Poor01/09/20251 yr agoIrrigation1910
Upper Helemano ReservoirHonolulu51Poor10/19/20223 yrs agoIrrigation1912
Kaupale ReservoirKauai50Poor10/03/20242 yrs agoIrrigation1910
Ipuolono ReservoirKauai50Poor05/20/20251 yr agoIrrigation1910
Twin ReservoirsKauai49Unsatisfactory10/04/20242 yrs agoOther1920
Papuaa ReservoirKauai48Poor11/06/2025this yearIrrigation1914
Kumano ReservoirKauai48Poor10/03/20242 yrs agoIrrigation1902
Huinawai ReservoirKauai47Poor12/11/2025this yearIrrigation1902
Pauwela ReservoirMaui47Poor04/26/20251 yr agoIrrigation1904
Kaloko ReservoirKauai46Poor02/25/20251 yr agoIrrigation1890
Manuhonuhonu ReservoirKauai45Poor12/11/2025this yearIrrigation1954
Peahi ReservoirMaui45Poor05/17/20251 yr agoIrrigation1924
Waikoloa Reservoir No. 1Hawaii44Poor01/23/20251 yr agoWater Supply1970
Haiku ReservoirMaui43Unsatisfactory04/26/20251 yr agoIrrigation1904
Olinda ReservoirMaui42Poor05/15/20251 yr agoWater Supply1918
Piiholo 50 Mg ReservoirMaui42Unsatisfactory05/08/20251 yr agoWater Supply1971
Maui Reservoir 20Maui42Poor01/30/20251 yr agoIrrigation1913
Halenanahu ReservoirKauai40Unsatisfactory11/06/2025this yearIrrigation1920
Aepoekolu ReservoirKauai40Poor10/03/20242 yrs agoIrrigation1910
Kepani ReservoirKauai40Poor11/20/2025this yearIrrigation1954
Maui Reservoir 24Maui39Poor05/31/20251 yr agoIrrigation1917
Maui Reservoir 15Maui39Poor05/17/20251 yr agoIrrigation1917
Helemano 6 ReservoirHonolulu38Poor09/10/20224 yrs agoIrrigation1915
Mau ReservoirKauai38Poor07/31/20251 yr agoIrrigation1901
Upper Field 14 ReservoirMaui38Poor06/06/20242 yrs agoIrrigation1985
Aahoaka ReservoirKauai38Poor01/25/20242 yrs agoIrrigation1910
Elima ReservoirKauai37Poor07/31/20251 yr agoIrrigation1901
Papaaea ReservoirMaui37Poor11/26/20241 yr agoIrrigation1902
Puu Koa ReservoirMaui37Poor12/16/20223 yrs agoIrrigation1985
Middle Field 14 ReservoirMaui36Unsatisfactory06/06/20242 yrs agoIrrigation2006
Hukiwai ReservoirKauai36Poor03/14/20242 yrs agoIrrigation1910
Aepoalua ReservoirKauai35Poor10/03/20242 yrs agoIrrigation1915
Maui Reservoir 33Maui35Poor02/20/20251 yr agoIrrigation1910
Reservoir 140Maui35Poor05/31/20251 yr agoIrrigation1926
Nuuanu Reservoir No. 1Honolulu34Poor04/04/20242 yrs agoFlood Risk Reduction1905
Paauilo ReservoirHawaii34Poor05/31/20251 yr agoIrrigation1975
Elua ReservoirKauai34Poor07/31/20251 yr agoIrrigation1902
Mahinahina ReservoirMaui34Poor05/08/20251 yr agoWater Supply1995
Puu O Hewa ReservoirKauai33Poor01/29/2026this yearIrrigation1915
Omao ReservoirKauai32Unsatisfactory03/06/20251 yr agoIrrigation1915
Honokowai ReservoirMaui31Poor04/22/20251 yr agoIrrigation1918
Maui Reservoir 14Maui31Unsatisfactory05/17/20251 yr agoIrrigation1913
Waikaia ReservoirKauai30Poor11/20/2025this yearIrrigation1951
Kehalani Offsite Retention BasinMaui30Poor04/22/20251 yr agoFlood Risk Reduction2003
Okinawa ReservoirKauai29Poor02/11/20251 yr agoIrrigation1920
Maui Reservoir 84Maui29Poor04/03/20251 yr agoIrrigation1918
Waita ReservoirKauai28Poor07/17/20251 yr agoIrrigation1906
Maui Reservoir 30Maui28Poor02/20/20251 yr agoIrrigation1917
Maui Reservoir 74Maui28Poor05/01/20251 yr agoIrrigation1916
Pinau ReservoirKauai28Unsatisfactory05/06/20251 yr agoOther1916
Maui Reservoir 42Maui27Poor03/13/20251 yr agoIrrigation1917
Halaula ReservoirKauai26Poor01/09/20251 yr agoIrrigation1905
Kaawanui ReservoirKauai26Poor10/22/20241 yr agoIrrigation1950
Aii ReservoirKauai26Poor02/11/20251 yr agoIrrigation1920
Maui Field 290 ReservoirMaui25Poor10/31/20241 yr agoIrrigation1997
Mana ReservoirKauai25Unsatisfactory11/21/20241 yr agoIrrigation1905
Kemoo 5 ReservoirHonolulu25Poor09/10/20224 yrs agoIrrigation1920
Kalihiwai ReservoirKauai25Poor02/22/20251 yr agoIrrigation1920
Oahu Reservoir 155Honolulu25Poor03/15/20251 yr agoIrrigation1916
Maui Reservoir 60Maui25Poor02/20/20251 yr agoIrrigation1917
Maui Reservoir 73Maui25Poor05/01/20251 yr agoIrrigation1908
Kapa ReservoirKauai24Poor03/14/20242 yrs agoIrrigation1901
Maui Reservoir 81Maui24Poor04/03/20251 yr agoIrrigation1920
Lower Kapahi ReservoirKauai24Unsatisfactory08/14/20251 yr agoOther1861
Waiakalua ReservoirKauai23Poor02/22/20251 yr agoRecreation1920
Maui Reservoir 90Maui22Poor04/10/20251 yr agoIrrigation1917
Maui Reservoir 21Maui22Poor01/30/20251 yr agoIrrigation1913
Maui Reservoir 61Maui21Poor02/27/20251 yr agoIrrigation1917
Puu Pulehu ReservoirHawaii21Poor03/22/20251 yr agoIrrigation1910
Maui Reservoir 25Maui20Poor02/13/20251 yr agoIrrigation1917
Mauka ReservoirKauai19Poor01/29/2026this yearIrrigation1910
Pia Mill ReservoirKauai17Poor01/29/2026this yearIrrigation1910
Maui Reservoir 92Maui16Poor04/10/20251 yr agoIrrigation1967
Maui Reservoir 70Maui16Poor03/06/20251 yr agoIrrigation1917
Maui Reservoir 52Maui15Poor02/27/20251 yr agoIrrigation1917

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