Diablo Dam
Diablo Dam is one of three dams along the upper Skagit River in Whatcom County, Washington and part of the Skagit River Hydroelectric Project that supplies Seattle with some of its power needs. The dam was built in Diablo Canyon, a gorge of solid granite with vertical walls rising 160 feet (49 m) from the river bed, yet were less than 100 feet (30 m) apart. Construction began in 1927, and was completed in 1930. The dam began generating electricity in 1936.[4]
| Diablo Dam | |
|---|---|
 | |
| Location | Washington, United States |
| Opening date | 1930 |
| Dam and spillways | |
| Type of dam | Concrete arch-gravity[1] |
| Impounds | Skagit River |
| Height | 389 ft (119 m)[1] |
| Length | 1,180 ft (360 m)[1] |
| Reservoir | |
| Total capacity | 88,500 acre⋅ft (109,200,000 m3)[1] |
| Catchment area | 1,103 sq mi (2,860 km2)[1] |
| Surface area | 990 acres (400 ha)[1] |
| Commission date | 1936 |
| Turbines | 2x 64.5 MW[2] |
| Installed capacity | 129 MW[2] |
| Capacity factor | 61% |
| Annual generation | 689,400,000 KWh[3] |
The result was a power-generating dam that holds a reservoir known as Diablo Lake. At the time it was completed, Diablo Dam, at 389 feet (119 m), was the tallest dam in the world.[5] Water from the dam operates two main generators, each with a capacity of 64.5 MW.[2] The dam and its original associated power generation infrastructure were listed on the National Register of Historic Places in 1989.[6]
Climate
The Western Regional Climate Center (WRCC) reports weather station 452157 at Diablo Dam since 1948, presently at 48°42′51″N 121°08′35″W with an elevation of 891 feet (272 m).[7] The dam is in a transitional maritime-mediterranean climate (Köppen (Cfb/Csb) depending on summer rainfall isotherm.
| Climate data for Diablo Dam, Washington (1991–2020 normals), extremes since 1914) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 62 (17) |
63 (17) |
76 (24) |
90 (32) |
103 (39) |
110 (43) |
106 (41) |
106 (41) |
101 (38) |
87 (31) |
65 (18) |
59 (15) |
110 (43) |
| Mean maximum °F (°C) | 48 (9) |
53 (12) |
64 (18) |
76 (24) |
86 (30) |
91 (33) |
96 (36) |
95 (35) |
88 (31) |
73 (23) |
55 (13) |
48 (9) |
98 (37) |
| Average high °F (°C) | 38.5 (3.6) |
43.2 (6.2) |
49.0 (9.4) |
57.2 (14.0) |
66.1 (18.9) |
70.3 (21.3) |
78.1 (25.6) |
78.8 (26.0) |
71.3 (21.8) |
57.5 (14.2) |
44.7 (7.1) |
38.1 (3.4) |
57.7 (14.3) |
| Daily mean °F (°C) | 34.0 (1.1) |
36.7 (2.6) |
41.1 (5.1) |
47.4 (8.6) |
55.2 (12.9) |
59.8 (15.4) |
65.8 (18.8) |
66.4 (19.1) |
60.1 (15.6) |
49.5 (9.7) |
39.8 (4.3) |
34.2 (1.2) |
49.2 (9.6) |
| Average low °F (°C) | 29.5 (−1.4) |
30.3 (−0.9) |
33.1 (0.6) |
37.5 (3.1) |
44.2 (6.8) |
49.4 (9.7) |
53.4 (11.9) |
53.9 (12.2) |
48.9 (9.4) |
41.5 (5.3) |
34.8 (1.6) |
30.2 (−1.0) |
40.6 (4.8) |
| Mean minimum °F (°C) | 17 (−8) |
21 (−6) |
26 (−3) |
31 (−1) |
36 (2) |
43 (6) |
47 (8) |
47 (8) |
41 (5) |
32 (0) |
24 (−4) |
19 (−7) |
11 (−12) |
| Record low °F (°C) | −2 (−19) |
0 (−18) |
9 (−13) |
24 (−4) |
28 (−2) |
33 (1) |
38 (3) |
37 (3) |
31 (−1) |
18 (−8) |
5 (−15) |
−2 (−19) |
−2 (−19) |
| Average precipitation inches (mm) | 12.25 (311) |
7.38 (187) |
8.16 (207) |
4.60 (117) |
2.71 (69) |
2.25 (57) |
1.25 (32) |
1.51 (38) |
3.41 (87) |
8.64 (219) |
13.66 (347) |
11.57 (294) |
77.39 (1,965) |
| Average snowfall inches (cm) | 12.2 (31) |
9.9 (25) |
4.2 (11) |
0.3 (0.76) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
0.0 (0.0) |
3.1 (7.9) |
16.0 (41) |
45.7 (116.66) |
| Average extreme snow depth inches (cm) | 11 (28) |
8 (20) |
4 (10) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
0 (0) |
2 (5.1) |
10 (25) |
16 (41) |
| Average precipitation days (≥ 0.01 inch) | 19 | 15 | 19 | 17 | 13 | 12 | 6 | 6 | 11 | 17 | 20 | 20 | 175 |
| Source: National Oceanic and Atmospheric Administration[8] | |||||||||||||
Panorama
References
- "Diablo (WA00170)". National Performance of Dams Program (Stanford University). Archived from the original on 2016-03-05. Retrieved 2014-03-04.
- "City Light Projects Harness Powerful Skagit River After Long, Hard Struggle" (PDF). The Concrete Herald. 1951-06-21. Retrieved 2009-09-05.
- "Diablo". Carbon Monitoring for Action (CARMA). Archived from the original on 2016-03-03.
- "Power Generation: Skagit Project - Diablo Dam". City of Seattle. Retrieved 2011-01-06. Includes construction photos.
- "Washington State Tourism Diablo Dam/Lake". Retrieved 2009-09-05.
- "National Register Information System". National Register of Historic Places. National Park Service. November 2, 2013.
- "Washington Station Inventory". Western Region Climate Center. Retrieved 2020-05-18.
- "NOWData Forecast Office Seattle, WA". National Oceanic and Atmospheric Administration. Retrieved August 8, 2022.
External links
- Diablo Dam, 1929-1932 (Part 1) (Part 2) (Part 3) – silent film clips of construction posted by Seattle Municipal Archives on YouTube
External links
- Historic American Engineering Record (HAER) documentation, filed under Newhalem, Whatcom County, WA:
- HAER No. WA-24-D, "Skagit Power Development, Diablo Powerhouse", 43 photos, 2 color transparencies, 6 measured drawings, 5 photo caption pages
- HAER No. WA-24-E, "Skagit Power Development, Incline Railway", 4 photos, 1 photo caption page
- HAER No. WA-24-F, "Skagit Power Development, Diablo Dam", 12 photos, 1 measured drawing, 2 photo caption pages