Map of the Salish Sea & Surrounding Basin

In the fall of 2009 and winter of 2010 the Washington State Board on Geographic Names, the Province of British Columbia Geographic Names Office, the U.S. Board on Geographic Names and the Geographical Names Board of Canada each approved the name ‘Salish Sea‘ as an official designation for the inland marine waters of Washington and British Columbia.

The SALISH SEA (Mer des Salish) extends from the north end of the Strait of Georgia and Desolation Sound to the south end of the Puget Sound and west to the mouth of the Strait of Juan de Fuca, including the inland marine waters of southern British Columbia, Canada and northern Washington, USA. These separately named bodies of water form a single estuarine ecosystem. Formally adopted by British Columbia and Washington State in 2009, ‘The Salish Sea’ as a name for these waters has been embraced by citizens on both sides of the border for years including the Coast Salish Gathering (the alliance of Coast Salish Tribal and First Nations leaders).

The Salish Sea is connected to the Pacific Ocean primarily via the Strait of Juan de Fuca (with relatively slight tidal influence from the north around Vancouver Island and through Johnstone Strait) and is contained by Vancouver Island and the Olympic Peninsula. In addition to the Gulf and San Juan Islands the watershed contains the lower Fraser River Delta and the Puget Lowlands as well as the Hood Canal, the Tacoma Narrows and Deception Pass.

Over 7 million people live within the drainage basin of the Salish Sea¹ (sometimes referred to as the “Georgia Basin – Puget Sound” watershed), including the cities of Vancouver, Seattle, Victoria, Olympia, Nanaimo, Bellingham, Everett, Port Angeles, Port Townsend and Tacoma.

Map Details & Usage

The Salish Sea and Surrounding Basin map was produced using a Geographic Information System (GIS) and publicly available spatial datasets for elevation, bathymetry and hydrology. Public use and reproduction for non-commercial purposes is permitted (see Printing).

Reproduction of this map for other websites or publications is permitted with the following conditions:
    – Please include a map citation:
         “Map of the Salish Sea & Surrounding Basin, Stefan Freelan, WWU, 2009”
    – Please let me know how you are using it
    – Sale of this map is prohibited without explicit permission from the cartographer.

Cartography and Map Production Notes

Cartographer:	Stefan Freelan, 2009
Software:	ESRI’s ArcGIS 9.2
Elevation Data:	SRTM (CGIAR-CSI)2
Bathymetry Data:	NOAA, Wa. DFW
Additional Data:	Wa. DNR, BC Digital Atlas, ESRI

Variations of color on the map are based on elevation (not actual landcover). Colors were chosen to mimic the ‘feel’ of the Pacific coast landscape (lighter greens for the lowlands, white for the mountain peaks). In addition a ‘hillshade’ effect has been created casting a virtual ‘shadow’ across the landscape to better depict the topography as if one is seeing a 3-dimensional shaded relief model. Similar color gradations are applied to the bathymetric data, again with a shadow effect applied as a ‘floorshade’ (i.e. a ‘hill’-shade for the ocean floor).

The Salish Sea basin boundary was derived from the elevation data following the peaks and ridges surrounding the Salish Sea. Areas outside the basin have been shaded with a semi-transparent overlay to highlight the geographic area draining directly into the Salish Sea. Note that the entire upper Fraser River watershed is technically a part of the Salish Sea drainage area. For this map, however, the Salish Sea basin has been defined as just that area draining directly into the ocean, including only the lower Fraser River watershed. See Salish Sea Basin Boundary Notes for a larger discussion on the use of the term ‘basin’ and the choice to exclude the watershed of the upper Fraser River. See the Combined Watersheds Draining into the Salish Sea for a map of of the full Salish Sea drainage area.

It is unusual for a map of this type to not include the cities, roads and borders that have been created by humans. Instead, this map focuses on the Salish Sea and it’s surrounding basin, defined not by political jurisdictions but by the geography of the water and land itself. As such, the text labels on the main map are likewise used only for the natural features defining and surrounding the Salish Sea.

Name Details

The name “Salish Sea” is not a historical term for the inland waters of British Columbia and Washington State. It was proposed by marine biologist Bert Webber in 1988. Dr. Webber recognized the need for a single geographic term that encompassed the entire ecosystem, spanning across the international border. Having a name to identify the entire area calls attention to the trans-border commonality of water, air, wildlife and history. Rather than being a replacement for any of the existing names, the designation Salish Sea is an overlay which includes and unites the established and familiar names of the various water and land bodies (the Strait of Georgia, Strait of Juan de Fuca, Puget Sound, Gulf Islands, San Juan Islands, etc.). The name also pays tribute to the Coast Salish peoples who have inhabited the area since long before Euro-American explorers first arrived. In 2009 the governments of both British Columbia and Washington officially adopted the name Salish Sea.³ See additional notes on the Naming of the Salish Sea. See also the Ish River Country map.

Salish Sea Details

The surface area of the Salish Sea (saltwater) is approximately 18,000 sq. km. (or about 7,000 sq. miles).⁴ Within the Salish Sea there are hundreds of islands (or even thousands, depending upon one’s definition of an ‘island’).

	Maximum Water Depths 5 6	Approx. Surface Area	% of Salish Sea (Saltwater)
Strait of Georgia (including the N. Gulf Islands)	410 m.	6,400 sq. km.	36 %
Strait of Juan de Fuca	250 m.	4,400 sq. km.	24 %
Desolation Sound	600 m.	1,100 sq. km.	6 %
Puget Sound	280 m.	2,500 sq. km.	14 %
Other BC(including Discovery Passage, Jervis Inlet, Howe Sound, S. Gulf Islands)	660 m.	2,000 sq. km.	11 %
Other WA (including Haro Strait, Rosario Strait, San Juan Islands, Bellingham Bay, Padilla Bay)	300 m.	1,600 sq. km.	9 %
British Columbia, Canada	660 m.	10,800 sq. km.	60%
Washington, USA	300 m.	7,200 sq. km.	40%
Combined Salish Sea	660 m.	18,000 sq. km.	100%

The surrounding Salish Sea drainage basin (not counting the upper Fraser River watershed) includes approximately 110,000 sq km (or about 42,000 sq miles). In addition to the human population, the ecosystem is home to over 200 different species of fish, over 100 different species of bird, 20 different species of marine mammal and over 3,000 different species of invertebrates. ^7 8

A note on ISLAND COUNT and SHORELINE LENGTH…

One would think that two of the most basic questions about the Salish Sea (or any body of water) would be: How Many Islands Are There? and What is the Length of the Shoreline? Interestingly, there is no single, correct answer to either of these questions.

The number of islands depends entirely upon how one defines an island: is a 1 acre rock an island? How about a 20 sq. m. rock? Do we measure those rocks/islands at high tide or low tide? And is the average high tide, or a high high tide? Does it need to have a name to be considered an island? Does it need to be inhabited?… It goes on and on, and (oddly) there does not seem to be any consensus or standard, either from geographers or government officials, as to what constitutes an island. Lacking such a definition, getting an accurate count is impossible. Somewhat related to the idea of defining an ‘island’ is the quality of our maps / data: assuming we had a working definition, do we determine what qualifies as an island via air photos, existing GIS data sets or field surveys? (Oh, and did I mention that sea levels, and thus potentially island existence, can change?)

Measuring shoreline length is even worse. Indeed, it turns out that it’s impossible to accurately measure a shoreline. Beyond the quality of the data one is using, it also depends upon the length of the measuring device/unit that is used to do the measuring. And the shorter the unit of measurement, the greater the measured length of shoreline is. This is known as the “Coastline Paradox” and the fractal mathematicians have lots to say on the subject (concluding that the length of any shoreline, if measured with a small enough measuring device, is infinite). This challenge isn’t unique to the Salish Sea, of course. Estimates for the length of the USA shoreline vary from 12,383 miles (Congressional Research Institute) to 18,924 miles (CIA) to 95,471 miles (NOAA)… that’s a pretty big range, all from the same federal government, for something as basic as ‘how long is our coast’…

Links

A few web links related to the Salish Sea… (see also a sample of where the Salish Sea Map has been used…)

A simple, interactive web map of the Salish Sea Basin 
WWU’s Salish Sea Institute 
Puget Sound Partnership
2009 Puget Sound Georgia Basin Ecosystem Conference: The Future of the Salish Sea
People for Puget Sound
The SeaDoc Society
Coast Salish Gathering
Wikipedia’s Salish Sea definition 
NOAA’s Salish Sea Activity Book for kids (coloring, etc.)
Crosscut articles: Setting Sail for the Salish Sea (2009) and The ‘Discovery’ of the Salish Sea (2011)

Footnotes

1. GIS calculations derived from US Census Bureau data and Canadian Census statistics ( http://www.censusfinder.com/ andhttp://www.metrovancouver.org/about/statistics/Pages/KeyFacts.aspx {KeyFacts-MetroVancouverPopulationEstimates1996-2007.pdf} andhttp://www.vancouverisland.com/information/ ).

2. 2008, Hole-filled SRTM for the globe Version 4, Jarvis, A., H.I. Reuter, A. Nelson, E. Guevara, (available from the CGIAR-CSI SRTM 90m Database: http://srtm.csi.cgiar.org ).

3. The Washington State Board on Geographic Names (http://www.dnr.wa.gov/AboutDNR/BoardsCouncils/WBNR/Pages/Home.aspx, see naming guidelines:http://www.dnr.wa.gov/publications/bc_geog_naming_guidelines.pdf)
The Province of British Columbia Geographic Names Office (http://geobc.gov.bc.ca/bcnames/contacts.htm)
The U.S. Board on Geographic Names ( http://geonames.usgs.gov/index.html)
The Geographic Names Board of Canada ( http://www.nrcan.gc.ca/earth-sciences/geography-boundary/geographical-name/related-organizations/geographical-names-board-of-canada/5816)
The ‘Discovery of the Salish Sea’ http://crosscut.com/2011/06/the-discovery-salish-sea/

4. GIS calculations derived from SRTM elevation data.²

5. Water Properties in the Straits of Georgia and Juan de Fuca, Emilie Davenne and Diane Masson, Institute of Ocean Sciences, Sidney, BC, Canada, 2001 ( http://www.pac.dfo-mpo.gc.ca/science/oceans/cotesud-southcoast/JdFG_e.pdf or here ).

6. The Puget Sound Model Summary, John H. Lincoln, University of Washington, Department of Oceanography, Seattle, Wa (http://exhibits.pacsci.org/Puget_Sound/PSSummary.html).

7. Species of Concern within the Georgia Basin Puget Sound Marine Ecosystem: Changes from 2002 to 2006, Nicholas A. Brown and Joseph K. Gaydos, The SeaDoc Society, 2007 ( http://www.vetmed.ucdavis.edu/whc/seadoc/pdfs/brown-gaydos07.pdf or here).

8. Puget Sound Georgia Basin Ecosystem, US EPA website, 2009 ( http://www.epa.gov/region10/psgb/ ).