Big Lake (Linn)

Reachcode: 17090004001067 | Area: 231.1 acres | Shoreline: 4.5 mi | View on Interactive Map

(From Atlas of Oregon Lakes, Johnson et al. 1985). Big Lake is a large mountain lake located just west of the crest of the Cascades and close to the heavily travelled Santiam Pass Highway. It lies below scenic Mt. Washington in a glacially carved valley known as Hidden Valley. This is an area of gentle topography and open meadows, underlain by permeable volcanic bedrock. Although the area receives about 90 inches of annual rainfall, there are no permanent surface streams entering the lake; most of the inflow is subsurface seepage, and there are a few small intermittent streams during the snowmelt season. There is no surface outflow. A dominant feature of the valley is an area of 8000 acres immediately west of the lake which was burned in 1967 by a lightning caused forest fire. However, the landscape appears to be recovering well and striking floral displays help reduce the visual contrast. 

Big Lake is one of the most popular recreation sites in this section of the Cascades. In the summer, visitors come for boating, swimming, and fishing. A 41-unit campground on the western shore has been established by the Willamette National Forest, and a large SeventhDay Adventist youth camp is on the opposite side of the lake. The lake used to be an excellent producer of brook trout, but they now run second to kokanee; cutthroat trout are also present. 

The water quality in Big Lake is exceptionally good and it is classified as ultraoligotrophic. Other nearby ultraoligotrophic lakes are Waldo Lake and Mink Lake. All three have conductivity values below 5 umhos/cm, and all lie at high elevations in drainage basins with mostly gentle slopes. Big Lake, however, receives much heavier use than do the others, yet remains very pristine and unproductive. Major ion concentrations, chlorophyll, and phosphorus are all very low, and transparency is very high. The phytoplankton biomass is very low, and the species present (predominantly Chromulina sp. and Oocystic pusilla on 8/29/81) support the ultraoligotrophic classification. Big Lake must be considered as sensitive to future cultural influences on water quality. Periodic monitoring of water quality is advisable so that possible future changes can be detected before serious disruptions occur.