page_title: Ballard Locks
section_title: Fish ladder
hierarchical_section_title: Ballard Locks / Fish ladder
caption_attribution_description: Entrance to the fish ladder, Hiram M. Chittenden Locks, Seattle, Washington, USA. Attraction water is visible, coming out of two places at the bottom of the fish ladder.
context_page_description: The Hiram M. Chittenden Locks, or Ballard Locks, is a complex of locks at the west end of Salmon Bay, in Seattle, Washington's Lake Washington Ship Canal, between the neighborhoods of Ballard to the north and Magnolia to the south.
  The Ballard Locks carry more boat traffic than any other lock in the US, and the Locks, along with the fish ladder and the surrounding Carl S. English Jr. Botanical Gardens attract more than one million visitors annually, making it one of Seattle's top tourist attractions. The construction of the locks profoundly reshaped the topography of Seattle and the surrounding area, lowering the water level of Lake Washington and Lake Union by 8.8 feet, adding miles of new waterfront land, reversing the flow of rivers, and leaving piers in the eastern half of Salmon Bay high and dry. The Locks are listed on the National Register of Historic Places and the American Society of Civil Engineers Historic Civil Engineering Landmarks.
context_section_description: 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.
  Pacific salmon are anadromous; they hatch in lakes, rivers, and streams—or, nowadays fish hatcheries—migrate to sea, and only at the end of their life return to fresh water to spawn. Prior to the Locks construction, no significant salmon runs existed here, as there was only a small drainage stream from Lake Union into Salmon Bay. In order to provide enough water to operate the Locks, Cedar River was rerouted into Lake Washington (which was lowered 9 feet). Cedar River originally flowed into the Duwamish River along with the White River from the South. White River was rerouted into the Puyalup River.  Cedar and White Rivers did support significant Salmon runs but also created severe flooding conditions for the early settlers. The rerouting of these two major rivers was a mixed blessing, while reducing flood threats, the Duwamish River salmon runs were decimated.  To rectify this situation, salmon runs were rerouted through the Locks, which included introducing a major run of Sockeye Salmon using stock from Baker River, Washington.
  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.
  The Corps rebuilt the fish ladder in 1976 by increasing the flow of attraction water and adding more weirs: most weirs are now one foot higher than the previous one. The old fish ladder had only 10 "steps"; the new one has 21. A diffuser well mixes salt water gradually into the last 10 weirs. As a part of the rebuilding, the Corps also added an underground chamber with a viewing gallery.
  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.
  The offspring remain in the fresh water until they are ready to migrate to the ocean as smolts. In a few years, the surviving adults return, climb the fish ladder, and reach their spawning ground to continue the life cycle. 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.
  Visitors to the locks can observe the salmon through windows as they progress 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.
caption: Attraction water is visible in two places in this photo; the lower part of the fish ladder snakes around the diffuser well.
exif: {"Image ImageDescription": "", "Image Make": "NIKON", "Image Model": "COOLPIX P2", "Image Orientation": "Horizontal (normal)", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "COOLPIX P2v1.0", "Image DateTime": "2007:09:17 17:07:36", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "284", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "300", "Thumbnail YResolution": "300", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "4596", "Thumbnail JPEGInterchangeFormatLength": "5111", "EXIF ExposureTime": "5/316", "EXIF FNumber": "19/5", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "64", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2007:09:17 17:07:36", "EXIF DateTimeDigitized": "2007:09:17 17:07:36", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "2", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "29/10", "EXIF MeteringMode": "Partial", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "15/2", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "2592", "EXIF ExifImageLength": "1944", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "1026", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "0", "EXIF FocalLengthIn35mmFilm": "36", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "None", "EXIF Contrast": "Normal", "EXIF Saturation": "Normal", "EXIF Sharpness": "Normal", "EXIF SubjectDistanceRange": "0"}