Lost Lake (225) (Linn)
Reachcode: 17090004001064 | Area: 79.3 acres | Shoreline: 2.2 mi | View on Interactive Map
(From Atlas of Oregon Lakes, Johnson et al. 1985) This is one of 14 Lost Lakes in Oregon and, to many residents, the best known because of its location adjacent to the heavily travelled Santiam Pass Highway, Oregon Highway 20. The lake lies within the Willamette National Forest just outside the Mt. Jefferson Wilderness. Lost Lake was probably formed about 3000 years ago at about the same time as Clear Lake, Linton Lake and others in this region of the Central Oregon Cascades. Lava flowing from the Sand Mountain Line of small volcanoes blocked a river channel to create a small basin of interior drainage which now holds the Lost Lake basin. Several small surface streams feed into the lake intermittently, but there is no visible outlet. Water leaves by seepage into the porous lava and by evapotranspiration. The water level fluctuates seasonally and is quite low in summer, dramatically so in drier years. Water-loving willows crowd the marshy shallows of the lake, particularly along the southeast shore. The bottom material is mostly mud mixed with cinders.
Lost Lake is stocked with eastern brook trout and rainbows and also has some native fish. Angling is permitted only until September 1 in order to protect fish that are forced to cluster as the water level drops in summer. There is usually a solid ice cover in early spring and ice-fishing is popular. No motorboats are allowed on the water. A Forest Service campground is located on the west shore adjacent to the highway.
Lost Lake is classified as mesotrophic, in contrast to the large number of oligotrophic lakes in the High Cascades. The concentrations of major ions, alkalinity, conductivity and pH are somewhat above average for Cascade Lakes. Algae populations are sparse and chlorophyl concentrations low, even though the phosphorus is somewhat above average for lakes of the region. The water is sufficiently transparent that the bottom is visible everywhere. This combination of characteristics indicates mesotrophy, but close to oligotrophy.