Editing Hetch Hetchy (section)

==Hetch Hetchy Project==
{{Infobox aqueduct
| name            = Hetch Hetchy Aqueduct
| image           = 
| image_size      = 
| starts          = [[Tuolumne River]]<br />{{Coord|37.852425|-119.991572}}
| ends            = [[Crystal Springs Reservoir]]<br />{{Coord|37.483508|-122.316306}}
| maint           = [[San Francisco Public Utilities Commission]]
| length          = {{convert|167|mi|abbr=on}}
| height          = 
| width           = 
| diameter        = 
| first_length    = 
| first_diameter  = 
| second_length   = 
| second_diameter = 
| third_length    = 
| third_diameter  = 
| capacity        = {{convert|366|cuft/s|m3/s|abbr=on}}
| begin           = 1914
| open            = 24 October 1934
| references      = {{GNIS|243393}}.<br />Note that map above only shows Bay Area portion of aqueduct.
}}
[[File:Hetchhetchyprojmap.jpg|thumb|right|upright=2|Map of Hetch Hetchy Project facilities]]

Hetch Hetchy Valley serves as the primary water source for the [[San Francisco|City and County of San Francisco]] and several surrounding municipalities in the greater [[San Francisco Bay Area]]. The dam and reservoir, combined with a series of aqueducts, tunnels, and [[hydroelectricity|hydroelectric plants]] as well as eight other storage dams, comprise a system known as the '''Hetch Hetchy Project''', which provides 80% of the water supply for 2.6 million people.<ref name="faq">
{{cite web
| url        = http://sfwater.org/index.aspx?page=518
| title        = Frequently Asked Questions About Hetch Hetchy Reservoir and the Regional Water & Power System
| publisher        = San Francisco Public Utilities Commission
| access-date        = 2013-05-31
| archive-url        = https://web.archive.org/web/20130823002441/http://sfwater.org/index.aspx?page=518
| archive-date        = 2013-08-23
| url-status        = dead
}}
</ref> The project is operated by the [[San Francisco Public Utilities Commission]]. The city must pay a lease of $30,000 per year for the use of Hetch Hetchy, which sits on federal land.<ref name=Upton>{{cite news|url=https://www.nytimes.com/2012/01/06/us/proposal-would-raise-rent-on-hetch-hetchy-reservoir.html|title=Water From Yosemite Is Still Cheap, for Now|last=Upton|first=John|date=6 January 2012|work=[[The New York Times]]|page=21A|access-date=21 May 2013}}</ref>{{sfn|Righter|2005|page=241}} The aqueduct delivers an average of {{convert|265000|acre feet|m3|abbr=on}} of water each year, or {{convert|31900000|cuft|m3|abbr=on}} per day, to residents of San Francisco and [[San Mateo County, California|San Mateo]], [[Santa Clara County, California|Santa Clara]] and [[Alameda County, California|Alameda]] Counties.<ref>{{cite web
| url        = http://www.aquafornia.com/index.php/where-does-californias-water-come-from/the-hetch-hetchy-aqueduct/
| title      = The Hetch Hetchy Aqueduct
| publisher  = Aquafornia
| date       = 2008-08-19
| access-date = 2013-05-31}}</ref>

As completed, O'Shaughnessy Dam is {{convert|910|ft|m}} long, spanning the valley at its narrow outlet.<ref name=sfwater/> The dam contains {{convert|675000|yd3|m3|abbr=on}} of concrete. The Hetch Hetchy Reservoir created by the dam has a capacity of {{convert|360400|acre.ft|km3|abbr=on}}, with a maximum area of {{convert|1972|acre|ha|abbr=on}} and a maximum depth of {{convert|306|ft|m}}.<ref name=sfwater/> From Hetch Hetchy Reservoir, the water flows through the Canyon and Mountain Tunnels to Kirkwood and [[Moccasin Dam|Moccasin Powerhouses]], which have capacities of 124 and 110 [[watt|megawatts]], respectively.<ref name="TRSystem">{{cite web|url=http://www.watereducation.org/userfiles/HHT09McGurk.pdf|title=Tuolumne River System|access-date=2013-05-26|archive-url=https://web.archive.org/web/20140702140442/http://www.watereducation.org/userfiles/HHT09McGurk.pdf|archive-date=2014-07-02|url-status=dead}}</ref> An additional hydroelectric system comprising [[Cherry Lake]], [[Lake Eleanor]] and the Holm Powerhouse is also part of the Hetch Hetchy Project, adding another 169 megawatts of generating capacity.<ref name="TRSystem"/> The entire system produces about 1.7 billion [[kilowatt hour]]s per year, enough to meet 20% of San Francisco's electricity needs.<ref name="TRSystem"/><ref name=calpower>{{cite web|url=http://energyalmanac.ca.gov/powerplants/Power_Plants.xlsx|title=Power Plants of California|work=California Energy Almanac|access-date=2013-05-23|archive-url=https://web.archive.org/web/20130520221257/http://energyalmanac.ca.gov/powerplants/Power_Plants.xlsx|archive-date=2013-05-20|url-status=dead}}</ref>

After passing through the powerhouses, Hetch Hetchy water flows into the {{convert|167|mi|km|abbr=on}} Hetch Hetchy Aqueduct which travels across the Central Valley. Just before reaching the Bay Area, it passes through the Irvington tunnel near the city of [[Fremont, California|Fremont]], and the aqueduct splits into four pipelines at {{coord|37.548104|-121.932041}}. These are called Bay Division Pipelines (BDPL) 1, 2, 3, and 4, with nominal pipeline diameters of 60, 66, 78, and 96 inches (1.5, 1.7, 2.0 and 2.4&nbsp;m, respectively).<ref>{{Cite book | last1 = Eidinger | first1 = J. M. | chapter = Seismic Retrofit of the Hetch Hetchy Aqueduct at the Hayward Fault | doi = 10.1061/40574(2001)75 | title = Pipelines 2001 | pages = 1–0 | year = 2001 | isbn = 978-0-7844-0574-1 }}</ref> All four pipelines cross the [[Hayward Fault Zone|Hayward fault]]. Pipelines 1 and 2 cross the San Francisco Bay to the south of the [[Dumbarton Bridge (California)|Dumbarton Bridge]], while pipelines 3 and 4 run to the south of the bay. In the Bay Area, Hetch Hetchy water is stored in local facilities including [[Calaveras Reservoir]], [[Crystal Springs Reservoir]], and [[San Antonio Reservoir]].<ref>{{cite web
| url        = http://www.sfwater.org/index.aspx?page=355
| title      = Serving 2.6 million residential, commercial and industrial customers
| publisher  = San Francisco Public Utilities Commission
| access-date = 2013-06-01}}</ref> Pipelines 3 and 4 <!-- not exactly sure about this, might want to do more research -->end at the [[Pulgas Water Temple]], a small park that contains classical architectural elements which celebrate the water delivery.<ref>{{cite web|url=http://www.sfwater.org/index.aspx?page=93|publisher=San Francisco Public Utilities Commission|title=Pulgas Water Temple|date=26 February 2024 }}</ref>

Water from Hetch Hetchy is some of the cleanest municipal water in the United States; San Francisco is one of six U.S. cities not required by law to filter its tap water, although the water is disinfected by [[Ozone#Aquaculture|ozonation]] and, since 2011, exposure to [[ultraviolet|UV]].<ref>
{{cite news
 |author       = Worth, Katie
 |title        = Hetch Hetchy water goes through ultraviolet rinse
 |work         = San Francisco Examiner
 |date         = 2011-07-18
 |access-date   = 2013-05-31
 |url          = http://www.sfexaminer.com/local/2011/07/hetch-hetchy-water-goes-through-ultraviolet-rinse
 |archive-url  = https://web.archive.org/web/20111101174844/http://www.sfexaminer.com/local/2011/07/hetch-hetchy-water-goes-through-ultraviolet-rinse
 |archive-date = 2011-11-01
 |url-status     = dead
}}
</ref> The water quality is high because of the unique geology of the upper Tuolumne River drainage basin, which consists mostly of bare granite; as a result, the rivers feeding Hetch Hetchy Reservoir have extremely low loads of sediments and nutrients. The watershed is also strictly protected, so swimming and boating are prohibited at the reservoir (although fishing is permitted at the reservoir and in the rivers which feed it),<ref>{{cite web
| url        = http://www.nps.gov/yose/planyourvisit/upload/hetchhetchy-sitebull.pdf
| title      = Hetch Hetchy Valley
| publisher  = U.S. National Park Service
| date       = March 2007
| access-date = 2013-05-31}}</ref> a measure which is considered unusual for US lakes outside the region.<ref name=":0">{{Cite news|url=https://www.sfchronicle.com/travel/article/A-historic-bid-for-limited-boating-at-Hetch-14474977.php|title=A historic bid for limited boating at Hetch Hetchy Reservoir|date=2019-09-28|newspaper=San Francisco Chronicle|language=en-US|access-date=2019-10-01 |last1=Stienstra |first1=By Tom }}</ref> In 2018, the [[United States Department of the Interior|Department of the Interior]] of the Trump administration began to consider a proposal to allow limited boating on the Hetch Hetchy Reservoir for the first time, supported by the advocacy group [[Restore Hetch Hetchy]] which argued that "San Francisco received [Hetch Hetchy's] benefits long ago, but the American people have not."<ref name=":0" /><ref>{{Cite web|url=https://www.latimes.com/environment/story/2019-10-23/yosemite-national-park-superintendent-removed-trump|title=Trump team reassigns Yosemite National Park superintendent; timing raises questions|last=Sahagun|first=Louis|date=2019-10-23|website=[[Los Angeles Times]] |language=en-US|access-date=2019-10-23}}</ref>

{{wide image|Hetch Hetchy Aqueduct in San Mateo County.jpg|x160px|The Hetch Hetchy Aqueduct pipelines 1 and 2 as viewed from the [[Emerald Lake Hills, California|Emerald Hills neighborhood]] in San Mateo County, California.|50%}}