Lake Washington

Infobox lake
lake_name = Lake Washington
image_lake = Murrow Memorial Bridge 07747.jpg
caption_lake = The Lacy V. Murrow floating bridge on the lake is the second longest such bridge in the world
image_bathymetry = Seattle-lakewashington-lakesammamish.png caption_bathymetry = Map of Lakes Washington and Sammamish
location = Washington
coords = coord|47|37|0|N|122|15|53|W|display=inline,title|region:US_type:waterbody|name=Lake Washington
type =
inflow = Sammamish, Cedar Rivers; Ravenna, Thornton, Kelsey, Juanita, and Coal Creeks
outflow = Lake Washington Ship Canal (1916)
catchment = 1,274 km² (300,000 acres)
basin_countries = United States
length = convert|22|mi|km|0
width =
area = 87.6 km² (21,500 acres)
depth = unit_ft|108|1
max-depth = unit_ft|214|1
volume = convert|2.9|km3|acre.ft|abbr=on|lk=on
residence_time =
shore =
elevation = unit_ft|16|0 above mean sea level, unit_ft|20.6|1 above Puget Sound mean lower low tide
islands = Mercer Island, Foster Island, Marsh Island, Ohler's Island, Pritchard Island
cities =

Lake Washington is the second largest natural lake in state of Washington (after Lake Chelan) and the largest lake in King County. It is bordered by the cities of Seattle on the west, Bellevue and Kirkland on the east, Renton on the south and Kenmore on the north, and surrounds Mercer Island. It is fed by the Sammamish River at its north end and the Cedar River at its south.

Lake Washington received its present name in 1854 after Thomas Mercer suggested it be named after George Washington, as the new Washington Territory had been named the year before. [cite book |last= Phillips |first= James W. |title= Washington State Place Names |year= 1971 |publisher= University of Washington Press |isbn= 0-295-95158-3 |pages= p. 156] The Duwamish called it "Lake Xacuabš" (Lushootseed: literally "great-amount-of-water"). [cite book |last= Thrush |first= Coll |title= Native Seattle: Histories from the Crossing-Over Place |year= 2007 |publisher= University of Washington Press |isbn= 0-295-98700-6 |pages= p. 245] Kenmore Air operates passenger seaplane service at Kenmore Air Harbor at the northern end of the lake.

Geography

Lake Washington is a ribbon lake, which are long, narrow and finger-like. Ribbon lakes were formed thousands of years ago during the ice age through glaciation: as the glacier bulldozed through a valley (glacial trough), it met bands of harder and softer rock. Erosion (mainly through abrasion: the process of rocks simply being scraped across the bedrock) was greater at the soft rock than the hard rock and so a dip was created. When the glacier melted the lake filled with the meltwater, which was held in by moraine (rock material) deposited by the glacier. A dam can also be created by the bands of harder rock either side of the softer rock. There is usually a river at both ends of a ribbon lake, one being the inflow, and the other, the outfow - though in the case of present day Lake Washington, both serve as inflow rivers.

Creeks and rivers

In addition to the Cedar and Sammamish Rivers, numerous small creeks and rivers feed the lake, including:
* Ravenna Creek
* Thornton Creek
* Kelsey Creek
* Juanita Creek
* Coal Creek

Canals and bridges

Before construction of the Lake Washington Ship Canal in 1916, Lake Washington's outlet was the Black River, which joined the Duwamish River and emptied into Elliott Bay. When the canal was opened the level of the lake dropped nearly nine feet (3 m). [ [http://www.historylink.org/essays/output.cfm?file_id=1444 Lake Washington Ship Canal] , HistoryLink.org] The canal to the Puget Sound became the lake's sole outlet, causing the Black River to dry up and disappear.

Concrete floating bridges were employed to span the lake because Lake Washington's depth and muddy bottom prevented the emplacement of the pilings or towers necessary for the construction of a causeway or suspension bridge. The bridges consist of hollow concrete pontoons that float atop the lake, anchored with cables to each other and to weights on the lake bottom. The roadway is constructed atop these concrete pontoons. Three floating bridges cross Lake Washington: the Evergreen Point Floating Bridge (officially the Governor Albert D. Rosellini Bridge - Evergreen Point) carries State Route 520 from Seattle's Montlake neighborhood to Medina while the Lacey V. Murrow Memorial Bridge and the Third Lake Washington Bridge (officially the Homer M. Hadley Memorial Bridge) carry Interstate 90 from Seattle's Mount Baker neighborhood to Mercer Island. The East Channel Bridge carries Interstate 90 from Mercer Island to Bellevue. The Evergreen Point, Lacey V. Murrow, and Third Lake Washington bridges are the longest, second longest, and fifth longest floating bridges in the world, respectively.

Many questioned the wisdom of concrete floating bridge technology after the sinking of a portion of the Lacey V. Murrow bridge on November 25, 1990. However, a Washington State Department of Transportation (WSDOT) investigation revealed that that incident resulted from the improper handling of hydrodemolition water being used during bridge renovations, rather than in any basic flaw in the bridge's concept or design. Concrete floating bridges continue to remain a viable means for the conveyance of vehicle traffic over Lake Washington. [cite book |last= Dorpat |first= Paul |coauthors= Genevieve McCoy |title= Building Washington: A History of Washington State Public Works |year= 1998 |publisher= Tartu Publications |isbn= 0-9614357-9-8 |pages= p. 124]

In 1950, approximately one year after the tolls were removed from the Murrow bridge, the inland ferry system on the lake came to an end, having operated since the 1880s. [cite book |last= Dorpat |first= Paul |coauthors= Genevieve McCoy |title= Building Washington: A History of Washington State Public Works |year= 1998 |publisher= Tartu Publications |isbn= 0-9614357-9-8 |pages= p. 36]

horeline cities and towns

The cities and towns bordering the lake, going clockwise from the west, are Seattle, Lake Forest Park, Kenmore, Kirkland, Yarrow Point, Hunts Point, Medina, Bellevue, Beaux Arts Village, Newcastle, Renton. The city of Mercer Island occupies the island of the same name, in the southern half of the lake.

The area of Lake Washington boasts several areas of high affluence. Bill Gates's estate is situated along its Medina waterfront, while Paul Allen lives on Mercer Island.

References