Lake Features

As with most Washington lowland lakes, Lake Burien is considered to have formed about 8,000 - 10,000 years ago when the latest iceage was ending and isolated remnants of ice remained bogged down in mineral debris left by widespread melting. The basin thus created was essentially a clay saucer that was pretty much leak-proof. The peaty bottom we now have - typically about 24" to 36" thick - must be assumed to be decomposed lake vegetation plus some alluvial deposits. (Those of us with buried logs in our lawns nay wonder how long decomposition goes on.) Relatively little sediments would have flowed into the lake through centuries as our topography provides a drainage area of only about 200 acres (now roughly bounded by 146^th SW on the north, 160^th SW on the south, 21^st on the west and 11^th or 12^th on the east). Surface drainage from this small area would not maintain our water level so nearly constant—typically about 19" reduction in depth by summer’s end—were it not for the springs that appear to be constantly supplying us. Several factors indicate this spring area to lie between Berg’s and Simpson’s about 75 yards from shore, at a depth of 30 to 33 feet (the deepest part of the lake). Swimmers have reported lower summer water temperatures in this section and winter observers note it to be among the last to freeze, both phenomena suggesting spring activity. Since the laws of physics and the State of Washington declare that water seeks its own level and since there are no substantial water sources this side of the Kent Valley with elevations exceeding Lake Burien (elev. 320 ft.), then the source presumably is the Cascades—which puts Lake Burien into pretty good company.