Hiram M. Chittenden Locks
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224902466
2008-07-10T22:37:39Z
Lauciusa
91346
Adding timing information about the spawning season
{{Infobox_nrhp | name =Chittenden Locks and Lake Washington Ship Canal
| nrhp_type =
| image = 1091-51.Jpg
| caption = An aerial view of the locks, facing west
| location= Salmon Bay, [[Seattle, Washington]]
| area =
| built =1906
| architect= Multiple
| architecture= Late 19th And 20th Century Revivals, Other
| added = [[December 14]], [[1978]]
| governing_body = [[Army Corps of Engineers]]
| refnum=78002751 <ref name="nris">{{cite web|url=http://www.nr.nps.gov/|title=National Register Information System|date=2007-01-23|work=National Register of Historic Places|publisher=National Park Service}}</ref>
}}
The '''Hiram M. Chittenden Locks''' are a complex of [[Canal lock|lock]]s that sit in the middle of [[Salmon Bay]], part of [[Seattle, Washington|Seattle]]'s [[Lake Washington Ship Canal]].<ref name="pamphlet 1 page 2">"Lake Washington Ship Canal and Hiram M. Chittenden Locks", p. 2.</ref> They are known locally as the '''[[Ballard, Seattle, Washington|Ballard]] Locks'''<ref name=citytoursite>[http://www.cityofseattle.net/tour/locks.htm Ballard Locks], Seattle Virtual Tour, City of Seattle web site. Accessed 21 September 2007.</ref><ref>"Lake Washington Ship Canal: Hiram M. Chittenden Locks" (2006), p. 6.</ref> after the neighborhood to their north. ([[Magnolia, Seattle, Washington|Magnolia]] lies to the south.)
The locks and associated facilities serve three purposes:
* To maintain the water level of the fresh water [[Lake Washington]] and [[Lake Union]] at 20–22 feet above [[sea level]]<ref name="pamphlet 1 page 2" /><ref name=citytoursite /> ([[Puget Sound]]'s mean low [[tide]]).{{Fact|date=September 2007}}
* To prevent the mixing of [[sea water]] from Puget Sound with the [[fresh water]] of the lakes ([[saltwater intrusion]]).<ref>"Lake Washington Ship Canal and Hiram M. Chittenden Locks", p. 2–3.</ref>
* To move boats from the water level of the lakes to the water level of Puget Sound, and vice versa.<ref name="pamphlet 1 page 3">"Lake Washington Ship Canal and Hiram M. Chittenden Locks", p. 3.</ref>
The complex includes two locks, a small (30 x 150 foot, 8.5 x 45.7 meter) and a large (80 x 825 foot, 24.4 x 251.5 meter).<ref name="pamphlet 1 page 8">"Lake Washington Ship Canal and Hiram M. Chittenden Locks", p. 8.</ref> The complex also includes a (235 foot, 71.6 meter) [[Dam#Spillways|spillway]] with six (32 x 12 foot, 9.8 x 3.7 meter) gates to assist in water-level control.<ref name="pamphlet 1 page 8" /> A [[fish ladder]] is integrated into the locks for migration of [[anadromous]] fish, notably [[salmon]].<ref name="pamphlet 2 passim">"The Lake Washington Ship Canal Fish Ladder", ''passim''.</ref><ref name="pamphlet 1 page 3" />
The grounds feature a visitors center,<ref name="pamphlet 1 page 4">"Lake Washington Ship Canal and Hiram M. Chittenden Locks", p. 4.</ref> as well as the [[Carl S. English, Jr., Botanical Gardens]].<ref>"Lake Washington Ship Canal and Hiram M. Chittenden Locks", p. 5.</ref>
Operated by the [[U.S. Army Corps of Engineers]],<ref>Sherrill Mausshardt and Glen Singleton, "Mitigating Salt-Water Intrusion through Hiram M. Chittenden Locks", ''Journal of Waterway, Port, Coastal and Ocean Engineering'', Vol. 121, No. 4, July/August 1995, pp. 224-227 , (doi 10.1061/(ASCE)0733-950X(1995)121:4(224)). [http://cedb.asce.org/cgi/WWWdisplay.cgi?9503505 Abstract] on site of [[American Society of Civil Engineers]] mentions that the locks are operated by the Corps. Accessed 21 September 2007.</ref> the locks were formally opened on [[July 4]], [[1917]],<ref>[[Walt Crowley]], [http://www.historylink.org/essays/output.cfm?file_id=3425 Turning Point 11: Borne on the 4th of July: The Saga of the Lake Washington Ship Canal], HistoryLink.org Essay 3425, July 3, 2001. Accessed 21 September 2007.</ref> although the first ship passed on [[August 3]], [[1916]].<ref>Gordy Holt, [http://seattlepi.nwsource.com/getaways/327523_shorttrips16.html Short Trips: Fascinating history sets the stage for a Ballard Locks outing], ''Seattle Post-Intelligencer'', Last updated August 15, 2007. Accessed 21 September 2007.</ref>They were named after [[U.S. Army]] Major [[Hiram M. Chittenden|Hiram Martin Chittenden]], the Seattle District Engineer for the Corps of Engineers from April 1906 to September 1908.<ref name="pamphlet 1 page 4" /> They were added to the [[National Register of Historic Places]] in 1978.<ref name="nris" />
==The locks proper==
[[Image:Seattle - Chittenden locks and Salmon Bay Terminal circa 1919.jpg|thumb|The Chittenden Locks shortly after their construction. The Carl P. English Gardens had not yet been started. The inset shows the nearby [[Fishermen's Terminal]].]]
As noted above, the complex includes two locks, a small (30 x 150 foot, 8.5 x 45.7 meter) and a large (80 x 825 foot, 24.4 x 251.5 meter).<ref name="pamphlet 1 page 8">"Lake Washington Ship Canal and Hiram M. Chittenden Locks", p. 8.</ref> Using the small lock when boat traffic is low conserves fresh water during summer, when the lakes receive less inflow. Having two locks also allows one of the locks to be drained for maintenance without blocking all boat traffic{{Fact|date=September 2007}} (pictures of the drained large lock are located in the [[Lock (water transport)#Illustrations|Lock (water transport)]] article).
The locks can elevate a 760-foot by 80-foot wide vessel 26 feet, from the level of Puget Sound at a very low tide to the level of freshwater Salmon Bay, in 10–15 minutes. The locks handle both pleasure boats and commercial vessels, ranging from [[kayak]]s to fishing boats returning from the [[Bering Sea]] to cargo ships. Over 1 million tons of cargo, fuel, building materials, and seafood products pass through the locks each year.<ref>"Lake Washington Ship Canal: Hiram M. Chittenden Locks" (2006), p. 6.</ref>
===How the locks work===
[[Image:How the Chittenden Locks work.jpg|thumb|300 px|How the locks work; see article text.]]
Vessels passing from the freshwater lakes (Lakes Washington and Union) to Puget Sound enter the lock chamber through the open upper gates ('''A''' in the accompanying diagram). The lower gates ('''B''') and the draining valve ('''D''') are closed. The vessel is assisted by the lockwall attendants who assure it is tied down and ready for the chamber to be drained.<ref name="pamphlet 1 page 2" />
Next, the upper gates ('''A''') and the filling valve ('''C''') are closed and the draining valve ('''D''') is opened allowing water to drain via gravity out to Puget Sound.<ref name="pamphlet 1 page 2" />
When the water pressure is equal on both sides of the gate, the lower gates ('''B''') are opened, allowing the vessels to leave the lock chamber.<ref name="pamphlet 1 page 2" />
The process is reversed for upstream locking.<ref name="pamphlet 1 page 2" />
{{clear}}
==Spillway==
[[Image:Ballardlocksspillway.jpg|thumb|Spillway]]
South of the small lock is a spillway dam with [[tainter gate]]s used to regulate the freshwater levels of the ship canal and lakes. The gates on the dam release or store water to maintain the lake within a two-foot range of 20 to 22 feet above sea level. This elevation is necessary for [[floating bridge]]s, mooring facilities, and vessel clearances under bridges.<ref name="pamphlet 1 page 2" />
"Smolt flumes" in the spillway help young salmon to pass safely downstream.<ref name="pamphlet 3 page 8" /> Higher water levels are maintained in the summer to accommodate recreation as well as to allow the lakes to act as a water storage basin in anticipation of [[drought]] conditions.<ref name="pamphlet 1 page 2" />
==Salt water barrier==
If excessive salt water were allowed to migrate into Salmon Bay, the salt could eventually damage the freshwater [[ecosystem]]. To prevent this, a basin was dredged just above (east of) the large lock. The heavier salt water settles into the basin and drains through a pipe discharging downstream of the locks area. In 1975, the saltwater drain was modified to divert some salt water from the basin to the fish ladder, where it is added via a diffuser to the fish ladder attraction water; see [[#Fish ladder|below]].<ref>"Lake Washington Ship Canal and Hiram M. Chittenden Locks", p. 2–3.</ref>
To further restrict saltwater intrusion, in 1966 a hinged barrier was installed just upstream of the large lock. This hollow metal barrier is filled with air to remain in the upright position, blocking the heavier salt water. When necessary to accommodate deep-draft vessels, the barrier is flooded and sinks to the bottom of the chamber.<ref name="pamphlet 1 page 3" />
==Fish ladder==
[[Image:Chittenden Locks - entrance to the fish ladder.jpg|thumb|Attraction water is visible in two places in this photo; the lower part of the fish ladder snakes around the diffuser well.]]
[[Image:Chittenden Locks - fish ladder viewing 02.jpg|thumb|Fish ladder viewing room.]]
[[Image:Chittenden Locks - fish ladder 01.jpg|thumb|View from above of the part of the fish ladder over the viewing room.]]
The fish ladder at the Chittenden locks is unusual—materials published by the federal government say "unique"—in being located where salt and fresh water meet. Normally, fish ladders are located entirely within fresh water.<ref name="pamphlet 2 page 2">"The Lake Washington Ship Canal Fish Ladder", p. 2. This document is in the public domain, and some of the wording here is almost verbatim from the pamphlet.</ref>
When the Corps of Engineers first built the locks and dam, they changed the natural drainage route of Lake Washington. The locks and dam blocked all salmon runs out of the [[Cedar River (Washington)|Cedar River]] watershed. (Pacific salmon are ''anadromous'': they hatch in lakes, rivers, and streams—or, nowadays [[fish hatchery|fish hatcheries]]—migrate to sea, and only at the end of their life return to fresh water to spawn.) To correct this problem, the Corps built a fish ladder as the locks were constructed to allow salmon to pass around the locks and dam.<ref name="pamphlet 2 page 2" />
The ladder was designed to use attraction water: fresh water flowing swiftly out the bottom of the fish ladder, in the direction opposite which anadromous fish migrate at the end of their lives. However, the attraction water from this first ladder was not effective. Instead, most salmon used the locks. This made them an easy target for predators; also, many were injured by hitting the walls and gates of the locks, or by hitting boat propellers.<ref name="pamphlet 2 page 2" />
The Corps rebuilt the fish ladder in 1976 by increasing the flow of attraction water and adding more [[weir]]s: most weirs are now one foot higher than the previous one. The old fish ladder had only 10 "steps"; the new one has 21, and a diffuser well mixes salt water in gradually through the last 10 weirs. As a part of the rebuilding, the Corps also added an underground chamber with a viewing gallery.<ref name="pamphlet 2 page 2" /><ref name="pamphlet 2 page 6" /><ref name="pamphlet 3 page 8">"Lake Washington Ship Canal: Hiram M. Chittenden Locks" (2006), p. 8.</ref>
The fish approaching the ladder smell the attraction water, recognizing the scent of Lake Washington and its tributaries. They enter the ladder, and either jump over each of the 21 weirs or swim though tunnel-like openings. They exit the ladder into the fresh water of Salmon Bay. They continue following the waterway to the lake, river, or stream where they were born. Once there, the females lay eggs, which the males fertilize. Most salmon die shortly after spawning.<ref name="pamphlet 2 page 2" /><ref name="pamphlet 2 page 3">"The Lake Washington Ship Canal Fish Ladder", p. 3.</ref>
The offspring remain in the fresh water until they are ready to return to the ocean as [[smolt]]s. In a few years, the surviving adults return, climb the fish ladder, and reach their spawning ground to continue the life cycle.<ref name="pamphlet 2 page 3" /> Of the millions of young fish born, only a relative few survive to adulthood. Causes of death include natural predators, commercial and sport fishing, disease, low stream flows, poor water quality, flooding, and concentrated developments along streams and lakes.<ref name="pamphlet 2 page 4">"The Lake Washington Ship Canal Fish Ladder", p. 4.</ref>
Visitors to the locks can observe the salmons' progress through windows along their route. Although the viewing area is open year-round, the "peak" viewing time is during spawning season, from about the beginning of July through mid-August. A public art work, commissioned by the Seattle Arts Commission, provides literary interpretation of the experience through recordings of Seattle poet Judith Roche's "Salmon Suite," a sequence of five poems tied to the annual migratory sequence of the fish.
[[Image:Lake Washington Ship Canal Fish Ladder pamphlet - The fish ladder in profile.jpg|thumb|left|500 px|The fish ladder in profile. The actual fish ladder makes several right angle turns, which are not reflected in this diagram. The pamphlet shows the the height of each weir. The last three weirs are adjustable to the level of Salmon Bay. Salt water is mixed with fresh water by the diffuser well in weirs indicated her by a darker gray. The longest weir in the ladder is for the viewing window.<ref name="pamphlet 2 page 6">"The Lake Washington Ship Canal Fish Ladder", p. 6.</ref>]]
{{clear}}
===Gallery: Migrating fish===
Among the species of salmon migrating routinely through the ladder at the Chittenden Locks are Chinook (king) Salmon (''[[Oncorhynchus tshawytscha]]''), Coho (silver) Salmon (''[[Oncorhynchus kisutch]]''), Sockeye (red) Salmon (''[[Oncorhynchus nerka]]''), and Steelhead (''[[Oncorhynchus mykiss]]'').<ref>"The Lake Washington Ship Canal Fish Ladder", p. 5–6.</ref>
<gallery>
Image:Lake Washington Ship Canal Fish Ladder pamphlet - ocean phase Chinook.jpg|Chinook: ocean phase
Image:Lake Washington Ship Canal Fish Ladder pamphlet - male freshwater phase Chinook.jpg|Chinook: male - freshwater phase
Image:Lake Washington Ship Canal Fish Ladder pamphlet - ocean phase Sockeye.jpg|Sockeye: ocean phase
Image:Lake Washington Ship Canal Fish Ladder pamphlet - male freshwater phase Sockeye.jpg|Sockeye: male - freshwater phase
Image:Lake Washington Ship Canal Fish Ladder pamphlet - ocean phase Coho.jpg|Coho: ocean phase
Image:Lake Washington Ship Canal Fish Ladder pamphlet - male freshwater phase Coho.jpg|Coho: male - freshwater phase
Image:Lake Washington Ship Canal Fish Ladder pamphlet - ocean phase Steelhead.jpg|Steelhead: ocean phase
Image:Lake Washington Ship Canal Fish Ladder pamphlet - male freshwater phase Steelhead.jpg|Steelhead: male - freshwater phase
</gallery>
==Gallery: the facility==
<gallery>
Image:NWS0002.jpg|Dedication on 4 July 1917
Image:Commodorepark.jpg|The locks and the adjacent Commodore Park
Image:Hiram M. Chittenden Locks-3.JPG|Boat and barge in the large lock
Image:Hiram M. Chittenden Locks-7.jpg|Control tower
Image:Hiram M. Chittenden Locks-2.JPG|Boat entering the small lock
Image:Chittenden Locks - sailboat tying off.jpg|Tying off at the small lock
Image:Hiram M. Chittenden Locks-5.jpg|Fish ladder
</gallery>
==Notes==
[[Image:Lake Washington Ship Canal Fish Ladder pamphlet 01.jpg|thumb|The cover of the U.S. government pamphlet "Lake Washington Ship Canal Fish Ladder" depicts the fish ladder at the locks.]]
{{reflist}}
==References==
* "Lake Washington Ship Canal and Hiram M. Chittenden Locks" (pamphlet), U.S. Government Printing Office: 1999-791-887. As work of the Federal Government, this document is in the public domain, and some of the wording in this article is almost verbatim from the pamphlet.
* "The Lake Washington Ship Canal Fish Ladder" (pamphlet), U.S. Government Printing Office: 1996-792-501. As work of the Federal Government, this document is in the public domain, and some of the wording in this article is almost verbatim from the pamphlet.
* "Lake Washington Ship Canal: Hiram M. Chittenden Locks" (pamphlet), US Army Corps of Engineers, 2006. As work of the Federal Government, this document is in the public domain, and some of the wording in this article is almost verbatim from the pamphlet.
==External links==
{{commonscat}}
*[http://www.nws.usace.army.mil/PublicMenu/Menu.cfm?sitename=lwsc&pagename=mainpage U.S. Army Corps of Engineers, Seattle District: Lake Washington Ship Canal and Hiram M. Chittenden Locks]
* [http://www.seattlewiki.org/wiki/Chittenden_Locks Chittenden Locks] on SeattleWiki
* [http://www.vrseattle.com/pages/browse.php?cat_id=75 Virtual tour of Chittenden (Ballard) Locks] on vrseattle.com: several 360° photographic panoramas of the locks.
[[Category:Transportation in Seattle, Washington]]
[[Category:Registered Historic Places in Seattle]]
[[Category:Locks of the United States]]
[[Category:Infrastructure-related Registered Historic Places]]
{{Registered Historic Places}}