dam california dam foot high concrete arch gravity dam california united_states forming lower end national park miles east san_francisco dam reservoir source provides water million people san_francisco municipalities west dam named engineer oversaw construction san_francisco sought water early 1890s project forward disastrous earthquake fire existing water supply compared valley scenic beauty chosen water quality hydroelectric potential location national park generated controversy act congress required federal protection reasoning public land developed public benefit construction dam started finished water delivered numerous delays dam raised increase capacity water supply power generation dam hydroelectric systems collectively known largely wild area sierra nevada supply municipal water requiring primary represented great environmental controversy debate dam reservoir continues today groups lobby restoration valley argue leaving dam place better economic environmental decision background late 19th century city san_francisco rapidly limited water supply depended intermittent local springs streams city looked east sierra nevada fed california largest rivers san_francisco mayor proposed build dam largest southern sierra rivers way increase stabilize city water supply report described best source sustainable water san_francisco managed secure water rights appeals federal government development unsuccessful san_francisco earthquake subsequent fire razed city dangerous city water supply system brought national light fourteen potential water sources considered city included lake tributaries sacramento rivers considered superior excellent dam site abundant sediment free water lower cost hydroelectric potential time isolated seldom visited valley visited intermittently gold surrounding lands limits utility development let grand scale proposed city valley known general public organizations spectacular beauty compared led naturalist opposed city san_francisco sought permission federal government build dam valley secretary interior responded san_francisco appeal granting city rights development stating unique lake beautiful meadow floor hydroelectric power generated eventually pay costs construction strongest supporters project chief pushed policy conservation use promoting sustainable development natural resources december president signed permitted san_francisco development project terms water power derived project public utilities private profit highly controversial bill passed senate vote consensus lay public land reasonable natural resources developed public benefit groups outraged federal government permission development december construction dam barely underway died leaving fight protracted battle years dam said dam water tanks peoples churches temple consecrated heart man argued necessary san_francisco destroy valley water supply pointing availability sites reasonable proximity including reported better cheaper source later similar scheme project provide water point san_francisco obsessed developing dismissed discarded rivers valleys served better created purpose construction work project began early shortly passage act city hired previously worked water supply systems boston new_york_city plan complex dam system civil engineer oversee construction design details project dam subsequently named honor construction dam commence city completed foot high dam lake eleanor provide water necessary provide electricity construction site larger dam initial construction dam cost largely financed revenue bonds issued city san_francisco transport workers materials city hired san_francisco engineer previous experience designing railways oversee construction railway mile standard gauge line followed narrow canyon remote dam site built workforce roughly railway allowed supplies shipped directly san_francisco sierra lines connected line railroad principally geared locomotives negotiate dangerous winding curves steep percent grades actual groundbreaking dam august san_francisco began preparing dam site construction workers began clearing trees prepare receiving waters future reservoir foot diameter tunnel later expanded foot dug south dam site timber diverted waters tunnel construction site future dam excavated hitting granite bedrock retaining wall poured upstream prevent water foundation hole granite artificially prepare receiving concrete concrete dam processed plant located shortly upstream construction site sand rock excavated abundant deposits valley mixed cement shipped local ranging yards metres diameter produce construction material dam beginning september concrete hoisted foot tower south gorge flow gravity construction site total concrete poured form dam standing feet feet foundations concrete placed february dam completed time second tallest dam united_states idaho dam reservoir filled time peak labor force worked project claimed lives men woman delivered completion powerhouse fed water canyon water deliveries reach san_francisco years completion dam years groundbreaking project dam designed adequate foundations unique stepped face order possible future increase dam height anticipation rapid growth demand water dam raised feet new outlet channels constructed accommodate increased height storage capacity helped increase summer generation downstream dam reservoir today completed final dimensions dam stands feet feet bedrock crest spans feet foot wide roadway crossing thickness dam wall reaches maximum feet base altogether structure contains concrete pounds steel aside normal water flows water released reservoir jet flow gates dam face controlled wide steel drum gates gates lowered capacity cubic feet second dam stretches miles section maximum capacity reservoir stores acre feet covering acres dam reservoir receive water upper square miles km2 watershed supplied water addition main stem accessed road runs miles terminates crest dam road open winter months water drives turbines located downstream powerhouse came online units added bringing total generating capacity serviced hydraulic head feet produces annual average million hours new powerhouse built replace old new located near lake lower capacity turbines generates million year fed water provides maximum head feet water diverted dam feeds provides percent municipal water million people firm water yield acre feet year million gallons day unique geology watershed consists shallow soils solid granite bedrock water flows reservoir exceptionally clear high quality quality maintained stringent protection watershed boating swimming prohibited fishing permitted reservoir rivers feed result san_francisco tap water united_states need said better quality water proposed removal dam controversial original construction environmental impact violations act city san_francisco act explicitly stated power water public purposes san_francisco sold power dam removal advocates stated san_francisco water power unfair damage tourism local environment caused dam reservoir draining reservoir removing dam restoring valley original state visitors park able enjoy natural beauty compared rivers available san_francisco replace water supply city currently unused share water lake don biggest reservoir opponents dam removal state estimated demolition cost billion poor investment especially regards resulting loss hydroelectric power replaced fossil fuel generation options available replace san_francisco water purity currently supplied guarantee valley successfully restored original valley floor actually product thousands years intensive controlled burning management native peoples lived area intervention forest grow place valley renowned meadows finally increased pressure new tourism cause environmental damage demonstrated crowded despite contested status dam environmental field occasional federal money set aside studying alternatives million provided president national_park_service budget local support removal relatively low san_francisco voters struck proposition ordered city study removal dam draft plan replace water vote percent proposition allocated million create feasibility study new water delivery systems place drained
O'Shaughnessy Dam (California)