- Deschutes County)
(From Atlas of Oregon Lakes, Johnson et al. 1985) Hosmer Lake, along the Cascade Lakes Highway in Central Oregon, was originally known as Mud Lake because the large population of trash fish would stir up the fine pumice bottom material. In 1962 the name was changed to honor Paul Hosmer, a long-time resident of Bend and a well-known amateur naturalist. The trash fish, which included a population of carp, had been eliminated with rotenone treatment in 1957. Atlantic salmon were stocked on an experimental basis starting in 1958, and Hosmer is the only lake west of the Mississippi River in which these fish have been planted successfully. All fishing must be done with barbless hooks, and Atlantic salmon must be returned to the lake. Brook trout are also in the lake, and can be kept if caught. There is little development at the lake, limited to small, rustic campgrounds and a few boats for rent.
Hosmer Lake is very shallow, with a mean depth of 3.2 feet and a maximum depth of 12 feet. The lake basin is long and narrow, with the main axis oriented north-south. Lava flows from Bachelor Butte were probably responsible for the formation of the lake, impounding the waters of Quinn Creek. There is some fluctuation of the water level, and in dry years there is no surface outlet. In wet years, water travels into a fissure about 50 yards downstream and disappears into the lava rock. Hosmer Lake is senescent water body, well on its way to becoming a marsh because of the encroachment of vegetation. Marshes extend into the lake, and the bottom is composed of mud and peaty deposits. The open water is restricted in many placed by mosses and submerged macrophytes; there are also extensive stands of emergent macrophytes. The lake is more productive than is usual for Cascade mountain lakes, and is classified as mesotrophic. The mineral content of the water is above average, as are the concentrations of chlorophyll and phosphorus. Water transparency is limited to about 8.2 feet (2.5 meters).