Olallie Lake (Jefferson)
Reachcode: 17070306002036 | Area: 194.9 acres | Shoreline: 4.3 mi | View on Interactive Map
(From Atlas of Oregon Lakes, Johnson et al. 1985). Olallie Lake is the largest of over 200 lakes and ponds that lie scattered about the base of Olallie Butte at the crest of the Cascade Range. It is within an area of 14,238 acres designated as the Olallie Lake Scenic Area, located in the southern tip of the Mt. Hood National Forest and part of the Clackamas Ranger District. The area was so designated in 1968 and is a very desirable summer recreation site. Forest roads extend into the area from three highways: U.S. Highway 26, 30 miles north of the area via Skyline Road; Oregon Highway 224, 25 miles northwest via Skyline and Clackamas River Roads; and Oregon Highway 22, 20 miles southwest via Skyline and Clackamas River Roads. The population centers of Portland and Salem provide most of the visitors to the area. Surfacing of the Skyline Road several years ago greatly increased the number of visitors. The name Olallie is used for a number of geographical features in Oregon, particularly along the Cascade Range. It is a word from Chinook jargon and means berries in general, or salmon berries. Its use along the Cascade Range generally meant huckleberries, and the area around Olallie Lake is covered with huckleberries that usually ripen by late August.
The recent geologic history of this high Cascade region is characterized by a combination of glaciation and recent volcanic activity. During the Pleistocene Epoch, the upland in the vicinity of Olallie Butte was covered by an ice sheet 500 to 1000 feet thick. The lower slopes of Olallie Butte were markedly steepened by this ice sheet and numerous landforms are evidence of this era. There are many U-shaped valleys, cirques, rock basins and some marshland. Glacial till, which covers the area, overlays an older andesite formation. The depth of the till varies from a thin veneer on ridges and slopes to relatively thick depths in morainal deposits and valley bottoms. The most conspicuous features are the numerous lakes that lie in basins in the rolling terrain of glacial till and moraines. Dozens of lakes visible from the summit of Olallie Butte are in rock basins scoured by the movement of glacial ice.
A volcanic landscape of this type typically has a poorly developed surface drainage system, and the lakes often have no identifiable inflow or outflow. Water to Olallie Lake is supplied by snowmelt runoff in seasonal streams, by direct precipitation, and by subsurface seepage through the volcanic terrain. A low dam with a barrier screen has been built across the outlet on Mill Creek to prevent the loss of stocked fish and to maintain the lake level. Thus the surface area of 188 acres is fairly constant. Mill Creek flows eastward to Long Lake.
The vegetation of the landscape around the lake is a forest complex typical for this elevation in the Cascades. Noble fir, pacific silver fir, western white pine, western hemlock, lodgepole pine, mountain hemlock and smaller amounts of Douglas fir, alpine fir, whitebark pine, Alaska yellow cedar and western red cedar make up the stand. The lodgepole pine has suffered considerably over the years from the attack of mountain pine beetles. There has been little harvesting of timber in the area in part because of the management objective of maintaining high recreation values. Marshy meadows of various sizes are also scattered throughout the area, one of the largest being Olallie Meadow, a 100 acre meadow lying just north of Olallie Butte.
Olallie Lake provides the opportunity for a variety of outdoor recreation activities. Several trails pass through the immediate area. One is a trail to the top of Olallie Butte, the dominant landform in the area, which is a composite volcanic cone of recent origin. From the top is a spectacular view, a 360 degree panorama of north-central Oregon. Fishing is the most important activity at Olallie Lake and at most of the other lakes in the Scenic Area. About a third of the northeast shoreline is developed, with a resort and a campground. Other shelters and picnic areas are scattered along the west shore, and there is a large campground on the narrow peninsula that juts into the lake. The lake is heavily used for swimming, boating, and fishing. It is stocked annually with rainbow trout and brook trout; kokanee are also present. No motorboats are allowed on the lake, in keeping with management objectives. The resort at the north end has boat rentals and supplies. The clear water also serves as a drinking water supply for the area.
Typical of most other lakes in this glaciated plateau, Olallie Lake is not very deep (average depth = 16.5 feet) and almost one-third of the lake is less than 10 feet deep. These littoral areas have mostly rock bottoms, whereas the rest of the lake has a bottom of mud, rock and debris. Considering the degree of development around its shores, Olallie Lake is in remarkably good condition. Mineral concentrationsare very low; concentrations of major ions, the alkalinity, and the conductivity are among the lowest observed anywhere in the state. The low mineral content is perhaps due to the fact that snow and rain, rather than inflowing streams, are the principal water source. The concentrations of chlorophyl and phosphorus are also exceptionally low. The water is sufficiently transparent to see the bottom even at the deepest point in the lake (43 feet). In all respects the lake is ultraoligotrophic, and seems to have changed very little since it was first surveyed in 1940 (Campbell 1940, McHugh 1972). Populations of phytoplankton are very low, and the species present are characteristic of very oligotrophic lakes. Although the lake is shallow, macrophytic growth is not supported on the rocky bottom. Because of its depth and altitude the water remains quite cool even in mid summer. Since Olallie Lake has been little affected by human encroachment, it is likely that it will remain oligotrophic for some time with proper management.