| Lake Eleanor | |
|---|---|
 Lake Eleanor's eastern shore in 2016, as viewed from a small peninsula | |
  Lake Eleanor  Lake Eleanor | |
| Location | Yosemite National Park,Tuolumne County,California,United States |
| Coordinates | 37°58′41″N119°52′45″W / 37.9779767°N 119.8790685°W /37.9779767; -119.8790685[1] |
| Type | reservoir |
| Primary inflows | Eleanor Creek |
| Basin countries | United States |
| Surface area | 953 acres (3.9 km2) |
| Water volume | 26,100 acre-feet (0 km3) |
| Surface elevation | 4,657 feet (1,419 m) |
Lake Eleanor is areservoir located in the northwestern backcountry ofYosemite National Park at an altitude of 4,657 feet (1,419 m). The reservoir has a capacity of 26,100 acre-feet (32,200,000 m3) and a surface area of 953 acres (3.9 km2).
The reservoir is situated in a glacier carved valley at an elevation of 4,600–4,700 feet (1,400–1,400 m). Prior to flooding, a smaller lake of approximately 1.5 by 0.5 miles (2.41 km × 0.80 km) and 200 feet (61 m) deep existed in the valley. The lake was fed by three streams, Kibbie Creek, Eleanor Creek, and Frog Creek. Before beingclearcut, the valley floor was moderately to densely forested with ayellow pine forest consisting primarily ofJeffrey andponderosa pines, with scatterings ofincense cedar,white fir, andblack oak.Manzanita and other shrub species made up the understory, and willow and other wetland species existed in the marshy areas around the lake and streams.[2]
An archeological survey done of the valley in 1985 while the reservoir was drained for maintenance provided evidence of prehistoric occupation of the valley. Due to the limited time of the study and the nature of working in the sediment of a reservoir, the extent of occupation was unable to be assessed.[2]
Settlement of Lake Eleanor valley by Europeans began in the mid-1800s. In the late 1800s, two homestead patents were taken out in the valley, one by Hermann Wolfe on the south shore and another by Horace J. Kibbe on the north shore,[2] which he occupied until 1913.[3]
The current lake was formed in 1918 by damming Eleanor Creek as part of theHetch Hetchy Reservoir system,[2] constructed to supply water and power to the city ofSan Francisco. The original smaller, natural lake was also named "Eleanor"[2] after the daughter ofJosiah Whitney, leader of theCalifornia Geological Survey in the 1860s.
Lake Eleanor Dam (National ID # CA00121) stands as a concrete multiple arch dam with a height of 68 feet (21 m) and a length of 1,260 feet (380 m). This first stage of the Hetch Hetchy project was built for year-round hydroelectric power generation, which was then sold to help finance construction of the largerO'Shaughnessy Dam, completed in 1923.[2]
That dams were planned for a valley in Yosemite National Park caused significant opposition. One of the most potent opponents was theSierra Club and its founding President,John Muir. After two vetoes byTheodore Roosevelt, on December 19, 1913,Woodrow Wilson signed theRaker Act permitting construction. It began in 1914.
The remote location dictated the use of an unusual multiple-arch structure here. It dramatically minimized the amount of concrete used in comparison with a gravity dam. Even more unusual, the concrete arches were elliptical rather than circular, the only multiple-arch dam ever built this way.[4] Chief designer for the San Francisco Board of Public WorksMichael O'Shaughnessy, along with hydraulic structural engineer R.P. McIntosh, were primarily responsible for the design.[5]
Still owned and operated by the city of San Francisco, the lake now provides opportunities for angling, hiking, and camping.
| Climate data for Eleanor Lake, California | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Record high °F (°C) | 75 (24) | 73 (23) | 79 (26) | 83 (28) | 87 (31) | 99 (37) | 101 (38) | 103 (39) | 98 (37) | 92 (33) | 80 (27) | 77 (25) | 103 (39) |
| Mean daily maximum °F (°C) | 47.1 (8.4) | 49.1 (9.5) | 53.5 (11.9) | 59.5 (15.3) | 66.2 (19.0) | 75.0 (23.9) | 85.3 (29.6) | 85.4 (29.7) | 79.4 (26.3) | 68.0 (20.0) | 57.9 (14.4) | 49.7 (9.8) | 64.7 (18.2) |
| Daily mean °F (°C) | 36.3 (2.4) | 38.1 (3.4) | 41.7 (5.4) | 47.7 (8.7) | 54.1 (12.3) | 61.7 (16.5) | 71.0 (21.7) | 70.3 (21.3) | 64.3 (17.9) | 54.0 (12.2) | 45.2 (7.3) | 38.9 (3.8) | 51.9 (11.1) |
| Mean daily minimum °F (°C) | 25.4 (−3.7) | 27.3 (−2.6) | 30.0 (−1.1) | 36.0 (2.2) | 41.9 (5.5) | 48.4 (9.1) | 56.7 (13.7) | 55.1 (12.8) | 49.1 (9.5) | 40.1 (4.5) | 32.4 (0.2) | 28.1 (−2.2) | 39.2 (4.0) |
| Record low °F (°C) | −7 (−22) | −12 (−24) | 1 (−17) | 13 (−11) | 22 (−6) | 24 (−4) | 35 (2) | 34 (1) | 29 (−2) | 20 (−7) | 10 (−12) | −2 (−19) | −12 (−24) |
| Averageprecipitation inches (mm) | 7.71 (196) | 7.16 (182) | 5.93 (151) | 3.50 (89) | 1.91 (49) | 0.71 (18) | 0.09 (2.3) | 0.09 (2.3) | 0.51 (13) | 2.27 (58) | 4.17 (106) | 7.45 (189) | 41.5 (1,055.6) |
| Average snowfall inches (cm) | 30.3 (77) | 26.2 (67) | 32.2 (82) | 10.2 (26) | 1.6 (4.1) | 0.1 (0.25) | 0.0 (0.0) | 0.0 (0.0) | 0.1 (0.25) | 1.5 (3.8) | 6.7 (17) | 24.1 (61) | 133 (338.4) |
| Average precipitation days(≥ 0.01 in) | 10 | 10 | 10 | 8 | 7 | 3 | 1 | 1 | 2 | 5 | 6 | 9 | 72 |
| Source: Western Regional Climate Center[6][7] | |||||||||||||
