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{{Infobox dam
| name = Culmback Dam
| image =Spada_Lake_west_of_Glacier_Peak.jpg
| image_caption =The reservoir, Spada Lake, seen from the air, with the dam on the left end of the lake
| name_official =
| dam_crosses = [[Sultan River]]
| res_name = Spada Lake
| location = [[Snohomish County]], [[Washington (U.S. state)|Washington]]
| operator = [[Snohomish County PUD]]<br />[[Everett, Washington|City of Everett]]
| dam_length = {{convert|640|ft|m|abbr=on}}
| dam_height = {{convert|262|ft|m|abbr=on}}
| dam_elevation_crest ={{convert|1450|ft|m|abbr=on}}<ref name=ctunnels>{{cite web |url=http://www.prism.washington.edu/crystal/Everett'sSystem.html |title=Everett Water System-Culmback Dam |accessdate=2009-02-20 |url-status=dead |archiveurl=https://web.archive.org/web/20080905170442/http://www.prism.washington.edu/crystal/Everett%27sSystem.html |archivedate=September 5, 2008 }}</ref>
| dam_width_base =
| construction_began = 1960
| opening =1965
| cost =
| res_capacity_total = {{convert|165774|acre.ft|m3|abbr=on}}
| res_catchment ={{convert|84|mi2|km2|abbr=on}}
| res_surface ={{convert|1870|acre|ha|abbr=on}}<ref name=c2>{{cite web|url=http://www.prism.washington.edu/crystal/EverettHistory.html |title=Jackson Hydro Project-History |accessdate=2009-02-21 |url-status=dead |archiveurl=https://web.archive.org/web/20071121063607/http://www.prism.washington.edu/crystal/EverettHistory.html |archivedate=November 21, 2007 }}</ref>
| plant_capacity =112 [[Megawatt|MW]]
| plant_hydraulic_head ={{convert|1165|ft|m|abbr=on}}
| plant_turbines =2x 47.5 MW [[Pelton wheel|Pelton]]<br />2x 8.4 MW [[Francis turbine|Francis]]
| plant_commission =1983
| plant_annual_gen =418 million [[Kilowatt hour|KWh]]
| coordinates = {{coord|47.9753|N|121.6865|W|type:landmark|display=inline,title}}
| extra =
}}
The '''Culmback Dam''' (also known as the '''George Culmback Dam''' or the '''Snoqualmie National Forest Dam''')<ref name=gnis>{{cite gnis|type=retired|id=1531308|name=Culmback Dam|accessdate=2009-02-22}}</ref> is a large rockfill [[hydroelectric]] and water supply [[dam]] on the [[Sultan River]], a tributary of the [[Skykomish River]], in [[Washington (U.S. state)|Washington]]. Built in 1965,<ref name=c1>{{cite web|url=http://www.everettwa.org/WFPVirtTour/-1-Culmback.html|title=Everett, Washington Water Supply- Culmback Dam|accessdate=2009-02-20|url-status=dead|archiveurl=https://web.archive.org/web/20071031094556/http://www.everettwa.org/WFPVirtTour/-1-Culmback.html|archivedate=2007-10-31}}</ref> the dam is {{convert|640|ft|m}} long at the crest and {{convert|262|ft|m}} high. Its reservoir, Spada Lake, provides water for 70 to 75 percent of [[Snohomish County]] and feeds the [[Jackson Hydroelectric Project|Jackson Hydro Project]], providing 112 [[megawatt]]s of clean energy to Snohomish county. Some critics charge that the dam has strongly impacted the runs of [[salmon]] and other migratory fish in the Sultan River by depleting gravel and sediment needed to line the riverbed.<ref name=fwee>{{cite web |url=http://www.fwee.org/news/getStory?story=1110 |title=Foundation for Water and Energy-Testing the waters |accessdate=2009-02-20 |archive-url=https://web.archive.org/web/20080603060809/http://fwee.org/news/getStory?story=1110 |archive-date=2008-06-03 |url-status=dead }}</ref> The dam's operator counters that Culmback Dam dramatically reduces flooding events, benefiting fish populations and the surrounding communities. The dam was named in honor of George Culmback, a former mayor of Everett.<ref name=c1/> Spada Lake is a reference to the character Count Spada in [[The Count of Monte-Cristo]].

The Dam is co-owned by the [[Snohomish County PUD]] and the [[Everett, Washington|City of Everett]] and is operated by the PUD. Water from Spada Lake is diverted through a [[Pipeline transport|pipeline]] to a powerhouse further downstream on the Sultan River. From the powerhouse, some water is returned to the river, and some is diverted to Lake Chaplain, where the water enters the Everett water supply system.<ref>{{cite web |url=http://www.snopud.com/jhp |title=Snohomish County PUD- Jackson Hydro Project |accessdate=2009-02-12 }}{{dead link|date=August 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref name=everett>{{cite web |url=http://www.ci.everett.wa.us/Get_PDF.aspx?pdfID=1399 |title=City of Everett Water Supply |accessdate=2009-02-20 |url-status=dead |archiveurl=https://web.archive.org/web/20111006150325/http://www.ci.everett.wa.us/Get_PDF.aspx?pdfID=1399 |archivedate=2011-10-06 }}</ref>

==Construction and other additions==
Prior to 1917 the City of Everett received its water supply from [[Woods Creek]], a tributary of the [[Snohomish River]]. Because of increasing water needs of large paper mills and factories, the city switched its water supply to the Sultan River basin via the tributary Chaplain Creek. The Chaplain Reservoir was created in 1929 with the completion of an earthfill dam, and later raised in 1942. This supply proved insufficient as well, so engineers looked to tap the [[main stem]] of the Sultan River, where an excellent dam site had been identified.

The Culmback Dam was built in two stages, or phases. Phase 1, which began in 1960 and ended in 1965, involved building the dam to a height of {{convert|200|ft|m}}, impounding a {{convert|40000|acre feet|m3|adj=on}} reservoir. The construction done during this phase served to replace the smaller, {{convert|22|ft|m|adj=on}} [[diversion dam]] {{convert|6.5|mi|km}} downstream<ref name=c1/> on the Sultan River. Phase 2, completed in 1984, involved raising the dam {{convert|62|ft|m}} to its present height, quadrupling the reservoir capacity. The second phase also included the pipeline connecting Spada Lake to a new hydroelectric powerhouse and from there to the Chaplain Reservoir.<ref>{{cite web |url=http://www.everettwa.org/default.aspx?ID=84 |title=History Lesson in Everett |accessdate=2009-02-21 |url-status=dead |archiveurl=https://web.archive.org/web/20100613034723/http://everettwa.org/default.aspx?ID=84 |archivedate=2010-06-13 }}</ref>

In June 2016, the PUD began demolition of the dam's [[sluiceway]] to re-open the upper Sultan River basin to spawning fish.<ref>{{cite news |last=Winters |first=Chris |date=February 13, 2017 |title=After 90 years, salmon are returning to upper Sultan River |url=https://www.heraldnet.com/news/after-90-years-salmon-are-returning-to-upper-sultan-river/ |work=The Everett Herald |accessdate=March 2, 2019}}</ref>

==Site==
[[Image:Sultan, WA - river from below bridges 01.jpg|thumb|right|200px|The Sultan River at [[Sultan, Washington]].]]
Culmback Dam and Spada Lake received water from a [[drainage basin]] of {{convert|84|sqmi|km2}} on the west slope of the [[Cascade Range]].<ref>{{cite web |url=http://www.everettwa.org/WFPVirtTour/-1-SultanRiver.html |title=EverettWashington.org- Sultan River |accessdate=2009-02-21 |url-status=dead |archiveurl=https://web.archive.org/web/20071031094423/http://www.everettwa.org/WFPVirtTour/-1-SultanRiver.html |archivedate=2007-10-31 }}</ref> Although the broad valley in which the reservoir now lies predates the last Ice Age, the canyon in which the dam was built was formed only about 1 million years ago, when the Sultan River was interrupted by the {{convert|1|mi|km|adj=on}} thick [[Laurentide Ice Sheet]], which rerouted the river from its original watershed, the [[Pilchuck River]]. The river eroded a narrow gorge to empty into the [[Skykomish River]], forming an ideal dam site.<ref name=fwee/>

The Sultan River, formed by the convergence of the North Fork of the Sultan River and Elk Creek, enters the lake from the east. Additional major contributors are the South Fork, which forms an arm of the lake close to Stickney Ridge, and Williamson Creek, which enters from the north at the base of [[Big Four Mountain]].

==Water supply and power==
Spada Lake is part of the water supply of the City of [[Everett, Washington|Everett]], Washington, serving 80 percent of [[Snohomish County, Washington|Snohomish County]].<ref name="Herald">{{cite news |last=Loerch |first=Jessi |date=August 15, 2014 |title=Spada Lake is a tranquil spot for a leisurely picnic, paddle or hike |url=https://www.heraldnet.com/life/spada-lake-is-a-tranquil-spot-for-a-leisurely-picnic-paddle-or-hike/ |work=The Everett Herald |accessdate=March 2, 2019}}</ref> This water supply consists of two lakes, the other being the much smaller, {{convert|17000|acre feet|m3|adj=on}} Lake Chaplain on Chaplain Creek, a tributary of the Sultan River. Most of the flow of the Sultan River is diverted at the dam into a {{convert|8|mi|km|adj=on}} [[penstock]] that flows to the 112 [[megawatt]] (MW) Jackson powerhouse further downstream, with an elevation drop of {{convert|1165|ft|m}}. At the powerhouse, the water feeds four turbine/generator units, consisting of two 47.5 MW [[Pelton wheel|Pelton]]-type turbines, and two 8.4 MW [[Francis turbine]]s. The water from the Pelton turbines is released directly into the Sultan River, while the rest of the water is piped to Lake Chaplain.<ref name=ctunnels/>

From Lake Chaplain, the water flows in four {{convert|4|ft|m|adj=on}} diameter pipes towards Everett. During flood events, water is also discharged back into the Sultan River through Chaplain Creek and the Sultan River Fresh-water Return Line.<ref name=everett/> The Culmback Dam is able to discharge water through an [[Spillway#Bell-mouth spillway|inverted-bell spillway]] that has a capacity of {{convert|62000|ft3|m3}} per second,<ref name=c2/> which is sufficient to handle the [[100-year flood]] flow of the Sultan River, which is calculated at {{convert|47000|ft3|m3}} per second.<ref>{{cite web |url=http://www.ci.sultan.wa.us/City_Hall/City_Boards_and_Commissions/Planning_Board/2009/2009-01-06/attachments/D-1_FEMA_Flood_Restudy_1-6-09.pdf |title=Sultan River Flood Flows |accessdate=2009-02-21 |url-status=dead |archiveurl=https://web.archive.org/web/20111006150649/http://www.ci.sultan.wa.us/City_Hall/City_Boards_and_Commissions/Planning_Board/2009/2009-01-06/attachments/D-1_FEMA_Flood_Restudy_1-6-09.pdf |archivedate=2011-10-06 }}</ref>

==Recreation==

The area around the dam and Spada Lake is visited by 5,000 people annually for a variety of recreational activities, including boating, hiking, fishing, and kayaking. The lake has two boat launches and prohibits combustion engines.<ref name="Herald"/>

==References==
{{reflist|33em}}

{{stack|{{Portal|United States|Water|Renewable energy}}}}

[[Category:Dams in Washington (state)]]
[[Category:Hydroelectric power plants in Washington (state)]]
[[Category:Rock-filled dams]]
[[Category:Buildings and structures in Snohomish County, Washington]]
[[Category:Dams completed in 1965]]
[[Category:Energy infrastructure completed in 1965]]
[[Category:1965 establishments in Washington (state)]]

Culmback Dam - Revision history

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