The area surrounding Lake Sammamish has been, in recent times, the most rapidly growing suburban district in the Greater Seattle Metropolitan Area. 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 conservation
Historically, runoff from the high precipitation in the lake's watershed was absorbed by the surrounding forests. 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 With rapid urbanization the forests have been replaced by impervious surfaces—roofs, roads, parking lots—and stormwater runoffs have increased flooding. 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. In May, 2010 the federal government asked the town of Sammamish to restrict development within from the lakeshore to protect local salmon and steelhead species. The report did not include Lake Sammamish kokanee salmon 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. Despite resistance to the report by the city of Sammamish, Issaquah already limits development within of the lake, Issaquah Creek and the East Fork of Issaquah Creek under the Shoreline Management Program. It is estimated that fewer than 100 Kokanee salmon remain in Lake Sammamish.
Beavers
The recent return of beaver 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. 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. 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. Research in the Stillaguamish River basin, approximately 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.
Recreation and parks
Lake Sammamish is bordered by Marymoor Park at the lake's north end, at its south end, and the East Lake Sammamish Trail. Lake Sammamish State Park provides nine public boat launches that can be accessed through a separate park entrance, for a fee, with parking and restroom facilities on site. The public can access the lake's west shores at Redmond's The privately owned , located in Bellevue, provides access from the west for a fee. Vasa Park offers one ramp for launching watercraft. Several housing developments own small, private parks that provide lake access for their residents. The main leisure activities include rowing, fishing, 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 personalityPat O'Day proposed that the Seafair Cuphydroplane races be moved to Lake Sammamish from Lake Washington, an effort that was unsuccessful. Lake Sammamish offers fishing enthusiasts a variety of species to pursue, including perch, smallmouth bass, largemouth bass, cutthroat trout, salmon, and steelhead trout, among others.
Events
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 was the 7th consecutive year.
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.