There are some that shape Seattle, including Lake Washington to the east (see above header image), a massive 21,500 acres of lake area and a max depth of 214 feet, draining a watershed of over 550 square miles and defines the entire inland edge of the city. In the medium size category is centrally located Lake Union, (below) which encompasses 580 acres, a max depth of 50 ft, and a similarly larger watershed. These, along with the Salish Sea to the west, and the Ship Canal and locks, literally form the hourglass shape of the City of Seattle and make up much of the story of the city in terms of water.
Nautical charts aside, we will have plenty more to come on these in terms of history and form, as well as some new efforts that have unlocked some mysteries hidden in their depths. For now, In addition to these large lakes, there are a number of small lakes that dot the landscape, remnants of the glacial action, namely in the form of kettle ponds. King County has a site for Lakes Data and Descriptions, which includes both, but of particular interest is the page for Small Lakes Data and Info, which allows access to information on these lake, including some simple yet compelling bathymetric maps. Green Lake falls into the small lake category (and also has been plagued with water quality issues. The bathymetry shows the current shoreline, which has a lake surface of 259 acres with a contributing watershed (although no contributing streams anymore) of 1875 acres.
For a slightly different visual,this 1938 W.P.A Sanitary Survey map (via the Seattle Municipal Archives page) shows a color coded look “Showing Depth Contours of Green Lake as of 1936”.
Those familiar with the story will know that the shoreline of the lake was changed a bit around the turn of the 20th century, and the addition of the waterfowl named island by said WPA also was not an original, but more on the historic manipulation of the shoreline of Green Lake at a future date.
For now, another interesting resource on the King County Lake site charting of various lake metrics, including water quality. As I mentioned, water quality issues, mostly in the form of toxic algae growth, have been problematic in Green Lake, with a peak issue in 2013 and a spike in 2016 Some historical data shows the situation in 2016, which shows a spike in Chlorphyll-a, which is an indicator of algae growth, and subsequent nutrient and temperature charts.
The smaller lakes in North Seattle also appear, including the smallest (yet deepest) Haller Lake, which has a surface are of 15 acres, with a max depth of 36 feet.
Bitter Lake has a surface area of 19 acres with a depth up to 31 feet.
Both are probably similar in size today as they were in the 1800s, based on the historical maps. The land uses and while the land use has changed, also probably have similar catchment zones. Maps on the site outline these watersheds, for instance the 331 acre drainage of the lake. As mentioned on the site: “This map shows the area of the watershed relative to the area of the lake. Generally speaking, the larger a watershed is relative to a lake, the greater the influence land use practices on lake water quality.”
An interesting tidbit on this was discovering the amazing Lakes of Washington by Ernest E. Walcott published in the early 1960s which was the basis for much of the bathymetric info included on the King County site and other resources. I’ll expand on at a later date, but in that vein, while outside of the city proper, the range of bathymetric maps, so I snipped a few pages out of this document, which includes lakes in King County that are part of the Lake Stewardship Program – just for a flavor of different lake forms in comparison (at least formally, as they do vary in scale) – all of which are derived from the work of Wolcott.
And if you still need your Lake Washington bathymetry fix, one I did find, for the more artistic (or looking for a gift for that special map nerd) are these fun wood fun maps (found amongst other local and national water bodies) sold on Etsy by ‘Beneath the Sail’
