Hart Lake (Lake)

Reachcode: 17120007341479 | Area: 7209.0 acres | Shoreline: 36.6 mi | View on Interactive Map

(From Atlas of Oregon Lakes, Johnson et al. 1985)  Hart Lake is the largest of the Warner Valley Lakes, a 40-mile chain of a dozen lakes in South-Central Oregon connected by sloughs and bordered by marshes. The Warner Valley is a fault-block basin, and the lakes are the remnants of pluvial Lake Warner, in existence during the Pleistocene Epoch. The eastern margin of the valley is bordered by an impressive escarpment, Hart Mountain, which rises 3000 feet above the valley floor. It is the site of the Hart Mountain National Antelope Refuge, established in 1936 to preserve habitat for antelope. It is also home to mule deer and bighorn sheep. The numerous Warner Valley Lakes provide habitat for egrets and white pelicans, and serve as nesting grounds for migratory waterfowl.

Hart Lake is the most permanent of the Warner Valley Lakes. Water is supplied by the overflow from Crump Lake and by a number of intermittent streams, primarily Honey Creek. Much of the outflow is used for irrigation, so that the lakes downstream from Hart Lake remain dry or almost dry except during very wet years. In some years, the lake is pumped dry by late summer. Because of large fluctuations in the lake level between wet and dry years, a dike was built about 1950 at the north end to store more water for irrigation. There is some recreational activity at the lake, mainly fishing. It is fished mainly for catfish, which are numerous and of good size. There are also largemouth bass, crappie, and some rainbow and cutthroat trout. The shoreline is in private ownership except where bordered by the refuge. There are no facilities at the lake for overnight camping.

The water quality characteristics of Hart Lake are largely a result of its shallowness. Water transparency is extremely limited by suspended inorganic particles which are stirred from the lake bottom by wave action. The transparency is thus not a reliable indicator of trophic state in this lake. Nutrient concentrations are very high (nitrate 0.17 mg/l and phosphorus 0.351 mg/1), and they tend to indicate a hypereutrophic condition. However, the chlorophyll concentration is typical of mesotrophic lakes; phytoplankton are not nutrient limited, but rather are restricted by available light (and perhaps other factors associated with the abundant suspended solids). Overall, the lake is classified as eutrophic, but is highly eutrophic.