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Lake Sammamish is a freshwater lake 8 miles (13 km) east of Seattle in King County, Washington, United States. The lake is 7 miles (11 km) long and 1.5 miles (2 km) wide, with a maximum depth of 105 feet (32 m) and a surface area of 8 sq mi (21 km2).[1] It lies east of Lake Washington and west of the Sammamish Plateau, and stretches from Issaquah in the south to Redmond in the north. At Issaquah it is fed by Issaquah Creek, and at Redmond it drains to Lake Washington via the Sammamish River.

Lake Sammamish
Lake Sammamish sunset.jpg
LocationKing County, Washington
Coordinates47°36′59″N 122°05′22″W / 47.6164888°N 122.089427247°W / 47.6164888; -122.089427247 (Lake Sammamish)Coordinates: 47°36′59″N 122°05′22″W / 47.6164888°N 122.089427247°W / 47.6164888; -122.089427247 (Lake Sammamish)
Primary inflowsIssaquah Creek
Primary outflowsSammamish River
Basin countriesUnited States
Max. length7.3 mi (11.7 km)
Max. width1.5 mi (2.4 km)
Surface area19.8 km2 (4,897 acres)
Average depth58 ft (18 m)
Max. depth105 ft (32 m)
Surface elevation30 ft (9.1 m)

The 98 sq mi (250 km2) Lake Sammamish watershed stretches from Redmond through Bellevue, and Issaquah to Preston and Hobart, and consists of numerous creeks which flow into the lake. Issaquah Creek is the largest tributary, furnishing over 70% of the lake's inflow.


The area surrounding Lake Sammamish has been, in recent times, the most rapidly growing suburban district in the Greater Seattle Metropolitan Area[citation needed]. During the late 1990s and early 2000s, the cities of Redmond, Snoqualmie, Fall City, Issaquah and Bellevue have grown substantially. The city of Sammamish was incorporated in 1999 because of suburban growth.

Ecology and conservationEdit

Historically, runoff from the high precipitation in the lake's watershed (nearly twice the 35 inches that Seattle gets each year) was absorbed by the surrounding forests.[1] Loose, sponge-like forest soils virtually eliminated runoff during winter storms and recharged groundwater aquifers which then released fresh water to streams in the dry summer months. With rapid urbanization the forests have been replaced by impervious surfaces—roofs, roads, parking lots—and stormwater runoffs have increased flooding.[2] The stormwater runoff carries sediment loads and toxic pollutants into streams and ultimately the lake, which generally has a negative impact on lake water clarity as well as fishes and wildlife.[2][3]

In May, 2010 the federal government asked the town of Sammamish to restrict development within 250 feet (76 m) from the lakeshore to protect local salmon and steelhead (Oncorhyncus mykiss) species. The report did not include Lake Sammamish kokanee salmon (Oncorhyncus nerka) among the species in trouble, although environmentalists and scientists said development along Lake Sammamish and tributary creeks have pushed the fish to the brink of extirpation.[4] Despite resistance to the report by the city of Sammamish, Issaquah already limits development within 200 feet (61 m) of the lake, Issaquah Creek and the East Fork of Issaquah Creek under the Shoreline Management Program.[4] It is estimated that fewer than 100 Kokanee salmon remain in Lake Sammamish.[5]


The recent return of beaver (Castor canadensis) to Lake Sammamish worries City of Issaquah and Lake Sammamish State Park officials who state that the mammals will cause flooding and burrow under roadways.[6][7] These officials are recommending relocation of the beaver families. On July 6, 2010, officials of the City of Issaquah have asked Washington Department of Fish and Wildlife to tear out a beaver dam on Tibbetts Creek in Lake Sammamish State Park because of concerns about potential flooding and barriers to salmon migration.[8]

In contrast, research on watersheds in the Northern United States and Canada shows that beavers provide ecological benefits by creating ponds that increase fish and bird abundance and diversity.[9] Research in the Stillaguamish River basin, approximately 50 miles (80 km) north of Lake Sammamish, found that extensive loss of beaver ponds resulted in an 89% reduction in coho salmon smolt summer production and an almost equally detrimental 86% reduction in critical winter habitat carrying capacity.[10]

Recreation and parksEdit

Lake Sammamish from Marymoor Park

Lake Sammamish is bordered by Marymoor Park at the lake's north end, Lake Sammamish State Park at its south end and East Lake Sammamish Trail. The main leisure activities include rowing, waterskiing, wakeboarding, wakesurfing, tubing, and jet skiing.

There is a public slalom course for waterskiing at the far north end of the lake, running from the west to the east. In the mid-1980s, local radio personality Pat O'Day proposed that the Seafair Cup hydroplane races be moved to Lake Sammamish from Lake Washington, an effort that was unsuccessful.[6]


  • Pirates vs Vikings is a massive water balloon fight between boats on lake Sammamish followed by an after party on a floating dance floor until 4am. Participants dress as either a pirate or Viking. 2015 is the 7th consecutive year.[better source needed][11]
  • Serial killer Ted Bundy abducted two women in broad daylight from the beach at Lake Sammamish State Park in 1974 by faking an injury and asking for their help.
  • Wife killer Randy Roth drowned his fourth wife Cynthia at Lake Sammamish in 1991 after taking off in a raft from Redmond's Idylwood Park.


  1. ^ a b "Lake Sammamish in Transition". Save Lake Sammamish. Retrieved 2010-07-05.
  2. ^ a b "Lake Sammamish Monitoring Overview". King County Water and Land Resources Division. Retrieved 2010-07-05.
  3. ^ S. J. Wenger et al. (2009). "Twenty-six key research questions in urban stream ecology: an assessment of the state of the science". Journal of the North American Benthological Society: 1080–1098. doi:10.1899/08-186.1. Retrieved 2010-07-05.CS1 maint: uses authors parameter (link)
  4. ^ a b Warren Kagarise (2010-05-18). "Cities asked to restrict shoreline development". Issaquah Press. Archived from the original on 2011-07-23. Retrieved 2010-07-04.
  5. ^ Warren Kagarise (2010-02-16). "Environmentalists wait to learn fate of Lake Sammamish kokanee salmon". Issaquah Press. Archived from the original on 2010-02-18. Retrieved 2010-07-04.
  6. ^ a b Staci Barsness (2010-07-02). "Lake Sammamish beaver invasion: Parks and City struggle to balance nature and community needs". Issaquah Reporter. Archived from the original on 2019-06-01. Retrieved 2010-07-04.
  7. ^ Gary Chittim (2010-07-02). "Beavers taking a bite out of Issaquah roadways". Archived from the original on 2011-06-13. Retrieved 2010-07-04.
  8. ^ Darren Dedo (2010-07-06). "City May Tear Down Beaver Dam At Popular Issaquah Creek". Q13Fox News. Archived from the original on 2011-07-21. Retrieved 2010-07-08.
  9. ^ Naiman, RJ; Johnston, CA; Kelley, JC (Dec 1988). "Alteration of North American streams by beaver". BioScience. 38 (11): 753–762. doi:10.2307/1310784.
  10. ^ M. M. Pollock, G. R. Pess, T. J. Beechie (2004). "The Importance of Beaver Ponds to Coho Salmon Production in the Stillaguamish River Basin, Washington, USA" (PDF). North American Journal of Fisheries Management: 749–760. Retrieved Feb 28, 2010.CS1 maint: uses authors parameter (link)
  11. ^ Archived 2015-07-21 at the Wayback Machine

External linksEdit