Lake Harriette (Klamath)
Reachcode: 18010203000446 | Area: 35.9 acres | Shoreline: 0.9 mi | View on Interactive Map
(From Atlas of Oregon Lakes, Johnson et al. 1985) Lake Harriette is a small, deep lake situated high in the southern Oregon Cascades. The colorful and rugged topography in this region is the result of an unusual geologic history. The deep blue cirque lake sits at the heart of a mountain mass that millions of years ago was a large composite volcano. Like Mt. Mazama to the north, the summit of this ancient cone collapsed on itself, creating a large caldera. However, instead of leaving a distinct crater similar to its famous neighbor, subsequent ice periods brought the deep scouring of glacial erosion, gouging the caldera rim into a ring of remnant peaks. Small lake basins and broad valleys now lie scattered in and around the old mountain, creating a jumbled and unexpected terrain. Mountain hemlock, Shasta fir, and lodgepole pine stand around Lake Harriette, but the slopes of this over-steepened, bowl-shaped amphitheatre basin are too unstable or rocky to support a dense growth of trees.
The lake is triangular in shape, and consists of a single basin with the deepest point near the middle. Surface temperatures remain cool throughout the summer, although the lake develops a pronounced thermal stratification with a thermocline near 10 feet (3.3 meters) deep. Water quality in the lake is excellent; the concentrations of major ions, conductivity and alkalinity are among the lowest measured in any of the lakes in Oregon. Phosphorus and chlorophyl concentrations are extremely low and water transparency is among the highest of Oregon lakes.
By all measures, Lake Harriette is ultraoligotrophic, a trophic state enhanced by several factors: the drainage basin is composed of rock types that are fairly resistant to weathering, thus limiting the supply of nutrients; vegetation growth is limited for the reasons noted above, further restricting nutrient input; and finally, the short growing season at this high altitude sets a limit on productivity. This combination restricts the natural reproduction of fish. However, it also enhances the transparency and aesthetic properties of the water in this jewel of a mountain lake.