Clear Lake (168) (Linn)
Reachcode: 17090004007099 | Area: 149.1 acres | Shoreline: 3.8 mi | View on Interactive Map
(From Atlas of Oregon Lakes, Johnson et al. 1985). One of eleven in the state with the same name, this Cascade mountain lake is well known as the source of the beautiful McKenzie River. It lies in forested terrain marked by numerous recent lava flows. Clear Lake is one of the most obvious examples in Oregon of a lake formed by a lava dam. About 3000 years ago hot lava, issuing from a vent in the Sand Mountain Line of craters to the east, poured across the McKenzie River, impounding its flow. The quickly-formed lake inundated a standing Douglas fir forest and dozens of snags are still located on the lake floor, partially preserved by the cold waters. This "underwater forest" can be seen through the remarkably clear waters and is a popular destination for boaters and scuba divers. Stream patterns in the drainage basin have been altered considerably in recent geologic times; lava has buried so many of the old river channels that much of the area is now drained by groundwater flow. Clear Lake is fed chiefly by large springs along the north and east shore; the largest of these is Big Spring, which gushes dramatically into the lake with a flow of ice cold water.
Clear Lake has long been an attractive recreation spot. The Santiam Fish and Game Association leases the lake from the National Forest and operates a small resort with cabins. A Forest Service campground is also available for visitor use. The Association is a sportsman's club, one of many throughout the state affiliated with the Oregon Wildlife Federation. Combined efforts of these organizations, public and private, have been instrumental in the protection of a quality recreation experience and the preservation of the resource. No motorboats are allowed on the lake. Fishing is usually good throughout the season. Both rainbow and eastern brook trout are stocked and there are some native cutthroat trout. There are apparently no trash fish in the lake.
Chemically and biologically, Clear Lake is unusual in a number of respects. Although the underwater trees are not "petrified," decomposition has been very slow because of the low level of biological activity in the water. The lake is also unusual in having slightly higher concentrations of major ions than most other Cascade lakes. The fact that inflow is primarily from subsurface drainage in volcanic rock may account for this aspect of the water's chemistry. As the name of the lake implies, the water in the lake is very transparent (Secchi disk depth = 56 feet; 17 meters) and there is very little growth of plankton or rooted macrophytes. Chlorophyl and transparency data indicate that it is ultraoligotrophic. The total phosphorus observation is anomalously high, again perhaps due to the influence of volcanic material on spring flow. Clear Lake is rather deep and may be expected to remain ultraoligotrophic. In spite of intense recreational use, the management history makes this a reasonable expectation.