Delintment Lake (Harney)

Reachcode: 17120004001271 | Area: 61.6 acres | Shoreline: 1.6 mi | View on Interactive Map

(From Atlas of Oregon Lakes, Johnson et al. 1985). Delintment Lake is a small artificial lake located on Delintment Creek, a tributary to Silver Creek in the northwest part of the Malheur Lake Drainage Basin. The site of the lake was originally beaver ponds surrounded by an open pine forest. It was improved by the Forest Service in 1940 to create a 35 acre lake, 12 feet deep, to be used for recreation. In 1953 it was further improved and enlarged to its present size by the cooperative effort of local interest groups. Surface runoff into the lake is intermittent, and from an area of about 1.2 square miles; on occasion water is diverted into the lake from a nearby stream. For the first few years the lake produced a number of large fish, although they were almost all killed off each winter because of the decay of weeds which causes oxygen depletion. Now the lake is restocked each year and usually provides good angling. There are two Forest Service campgrounds on the shoreline and a good boat ramp.

Although it is shallow, Delintment Lake sometimes develops a thermal stratification. The concentration of ions is somewhat above average for the state as a whole, but typical of reservoirs east of the Cascades. However, the lake does have a history of water quality problems. The concentration of phosphorus is high and stimulates the growth of phytoplankton and macrophytes, which now cover most of the muddy bottom. Water transparency is average (8.9 feet; 2.7 m) and chlorophyl concentrations are moderately high. Based upon the concentration of phosphorus and the extensive growth of macrophytes, the lake is classified as eutrophic. Field studies by the Environmental Protection Agency indicated that this small, shallow lake would be a good place to try nutrient inactivation for plankton control. This might reduce the algae, but presumably have little effect on the very thick beds of macrophytes. It has been proposed that the dam be raised to deepen the lake; if so the weeds would probably disappear from deep water areas, while remaining in a fringe in the shallow water along the shore. The principal use of the lake is for fishing, and reduction of weeds in part of the lake would provide more access for the fishermen.