Tallest Dams in Washington

Washington has 815 dams with recorded heights. The tallest is Mossyrock at 606 feet. Taller dams impound more water and carry greater potential energy, which is why height is a key factor in hazard classification and inspection requirements.

#	Dam	County	Height (ft)	Type	Purpose	Hazard	Year
1	Mossyrock	Lewis	606	Arch	Hydroelectric	High	1968
2	Grand Coulee Dam	Okanogan	550	Concrete	Flood Risk Reduction	High	1941
3	Ross	Whatcom	540	Concrete	Hydroelectric	High	1949
4	Mud Mountain Dam	King	425	Rockfill	Flood Risk Reduction	High	1948
5	Swift No. 1	Skamania	412	Earth	Hydroelectric	High	1958
6	Diablo	Whatcom	389	Concrete	Hydroelectric	High	1929
7	Boundary	Pend Oreille	360	Concrete	Hydroelectric	High	1967
8	Asamera Cannon Mine Tailings Dam	Chelan	340	Earth	Flood Risk Reduction	High	1986
9	Alder	Pierce	330	Concrete	Hydroelectric	High	1945
10	Yale	Cowlitz	323	Earth	Hydroelectric	High	1953
11	Tieton Dam	Yakima	319	Rockfill	Flood Risk Reduction	High	1925
12	Merwin	Cowlitz	313	Arch	Hydroelectric	High	1931
13	Gorge	Whatcom	300	Concrete	Hydroelectric	High	1961
14	Centralia Coal Mine Dam No 3d	Lewis	285	Earth	Tailings	Low	1988
15	Lower Baker	Skagit	285	Arch	Hydroelectric	High	1927
16	Cushman No 2	Mason	275	Arch	Hydroelectric	High	1930
17	Cushman No 1	Mason	272	Arch	Hydroelectric	High	1926
18	Culmback	Snohomish	262	Rockfill	Hydroelectric	High	1983
19	Tapps Lake Dike No 14	Pierce	256	Earth	Recreation	Low	1911
20	Mayfield	Lewis	250	Arch	Hydroelectric	High	1963
21	Mount St. Helens Sediment Retention Structure	Cowlitz	239	Earth	Flood Risk Reduction	High	1988
22	Howard A. Hanson Dam	King	235	Rockfill	Flood Risk Reduction	High	1962
23	Chief Joseph Dam	Douglas	230	Gravity	Hydroelectric	High	1955
24	Masonry Dam	King	230	Arch	Hydroelectric	High	1914
25	Little Goose Lock And Dam	Columbia	226	Concrete	Navigation	High	1970
26	Lower Monumental Lock And Dam	Franklin	226	Concrete	Navigation	High	1969
27	Long Lake	Stevens	225	Gravity	Hydroelectric	High	1915
28	La Grande	Thurston	217	Concrete	Hydroelectric	High	1944
29	Ice Harbor Lock And Dam	Walla Walla	208	Concrete	Navigation	High	1962
30	Wanapum	Kittitas	206	Gravity	Hydroelectric	High	1965
31	Coldwater Debris Dam	Cowlitz	200	Earth	Other	Undetermined	1981
32	O'sullivan Dam	Grant	200	Earth	Flood Risk Reduction	High	1949
33	Tolt River - South Fork	King	200	Earth	Water Supply	High	1962
34	Castle Lake Debris Dam	Cowlitz	190	Earth	Other	Undetermined	1980
35	Casad Dam	Kitsap	190	Arch	Water Supply	High	1956
36	Kinross Gold Kettle River Tailings Dam	Ferry	189	Other	Tailings	High	1994
37	Priest Rapids	Grant	187	Gravity	Hydroelectric	High	1961
38	Spirit Lake Outlet Tunnel	Skamania	184	Earth	Flood Risk Reduction	Undetermined	1985
39	Wynoochee	Grays Harbor	175	Gravity	Water Supply	High	1972
40	Wells	Chelan	160	Gravity	Hydroelectric	High	1968
41	Skookumchuck	Thurston	160	Earth	Hydroelectric	High	1970
42	North Dam	Grant	145	Earth	Flood Risk Reduction	High	1951
43	Cowlitz Falls	Lewis	145	Concrete	Hydroelectric	Significant	1994
44	Mill Creek Storage Dam	Walla Walla	145	Earth	Flood Risk Reduction	High	1942
45	Icon Materials Pond 4	King	140	Earth	Water Supply	High	1997
46	Centralia Coal Mine Dam No 3b	Lewis	140	Earth	Tailings	Significant	1980
47	Centralia Coal Mine Dam No 3c North	Lewis	134	Earth	Tailings	Significant	1987
48	Rocky Reach	Chelan	130	Gravity	Hydroelectric	High	1962
49	Pinto Dam	Grant	130	Earth	Flood Risk Reduction	High	1948
50	Keechelus Dam	Kittitas	128	Earth	Flood Risk Reduction	High	1917

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