Largest Reservoirs in Hawaii

Hawaii has 122 dams with recorded storage capacity. The largest is Waita Reservoir with 9,900 acre-feet of maximum storage. One acre-foot equals about 326,000 gallons — enough to supply roughly two households for a year.

#	Dam	County	Max Storage (acre-ft)	Height (ft)	Purpose	Year
1	Waita Reservoir	Kauai	9,900	28	Irrigation	1906
2	Wahiawa Dam	Honolulu	9,200	98	Irrigation	1906
3	Kualapuu Reservoir	Maui	5,082	58	Irrigation	1969
4	Kaneohe Dam	Honolulu	4,500	83	Flood Risk Reduction	1980
5	Nuuanu Dam No. 4	Honolulu	3,600	73	Flood Risk Reduction	1910
6	Alexander	Kauai	2,777	141	Hydroelectric	1931
7	Puukapu Watershed Retarding Dam R-1	Hawaii	1,450	12	Flood Risk Reduction	1965
8	Kapaia Reservoir	Kauai	1,114	53	Irrigation	1910
9	Ku Tree Reservoir	Honolulu	970	90	Other	1925
10	Papuaa Reservoir	Kauai	921	48	Irrigation	1914
11	Puu Lua Reservoir	Kauai	888	110	Fish and Wildlife Pond	1925
12	Wailua Reservoir	Kauai	842	34	Irrigation	1920
13	Upper Helemano Reservoir	Honolulu	700	51	Irrigation	1912
14	Aepoeha Reservoir	Kauai	670	42	Irrigation	1913
15	Twin Reservoirs	Kauai	520	49	Other	1920
16	Kehalani Offsite Retention Basin	Maui	490	30	Flood Risk Reduction	2003
17	Kauai Lagoons	Kauai	470	13	Other	1987
18	Halenanahu Reservoir	Kauai	460	40	Irrigation	1920
19	Aepo Reservoir	Kauai	457	74	Irrigation	1901
20	Ipuolono Reservoir	Kauai	450	50	Irrigation	1910
21	Puu Pulehu Reservoir	Hawaii	445	21	Irrigation	1910
22	Kaneha Reservoir	Kauai	420	51	Irrigation	1910
23	Elua Reservoir	Kauai	360	34	Irrigation	1902
24	Mauka Reservoir	Kauai	345	19	Irrigation	1910
25	Opaeula 01 Reservoir	Honolulu	320	71	Irrigation	1910
26	Kahakapao Reservoirs	Maui	309	54	Water Supply	1990
27	Puu Opae Reservoir	Kauai	295	41	Irrigation	1930
28	Maui Reservoir 73	Maui	290	25	Irrigation	1908
29	Maui Reservoir 52	Maui	287	15	Irrigation	1917
30	Honokowai - Structure #8	Maui	281	50	Flood Risk Reduction	1995
31	Haiku Reservoir	Maui	266	43	Irrigation	1904
32	Piwai Reservoir	Kauai	261	56	Irrigation	1916
33	Maui Reservoir 60	Maui	260	25	Irrigation	1917
34	Maui Reservoir 74	Maui	248	28	Irrigation	1916
35	Kalihiwai Reservoir	Kauai	242	25	Irrigation	1920
36	Kaupale Reservoir	Kauai	240	50	Irrigation	1910
37	Kahana Nui Dam	Maui	225	58	Flood Risk Reduction	1984
38	Waiakalua Reservoir	Kauai	220	23	Recreation	1920
39	Aahoaka Reservoir	Kauai	210	38	Irrigation	1910
40	Maui Reservoir 90	Maui	201	22	Irrigation	1917
41	Huinawai Reservoir	Kauai	196	47	Irrigation	1902
42	Omao Reservoir	Kauai	194	32	Irrigation	1915
43	Lower Kapahi Reservoir	Kauai	194	24	Other	1861
44	Waikoloa Reservoir No. 1	Hawaii	190	44	Water Supply	1970
45	Waikoloa Reservoir No. 3	Hawaii	190	54	Water Supply	1985
46	Waikoloa Reservoir No. 2	Hawaii	190	35	Water Supply	1975
47	Waimea 60 Mg Reservoir	Hawaii	189	52	Irrigation	1957
48	Waimanalo 60 Mg Reservoir	Honolulu	182	65	Irrigation	1993
49	Kumano Reservoir	Kauai	175	48	Irrigation	1902
50	Maui Reservoir 61	Maui	175	21	Irrigation	1917

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