Drews Reservoir (Lake)

Reachcode: 18020001001188 | Area: 4697.4 acres | Shoreline: 29.8 mi | View on Interactive Map

(From Atlas of Oregon Lakes, Johnson et al. 1985).  Drews Reservoir is a large irrigation impoundment in the Drews Valley of south-central Oregon. The reservoir was formed in 1911 with the damming of Drews Creek about nine miles northwest of Goose Lake, its purpose being to distribute flows more evenly during the latter part of the growing season in July and August. The stream, the valley, and in turn the reservoir were named for Lieutenant-Colonel C. S. Drew, in command of the Owyhee Reconnaissance of the First Oregon Cavalry in 1864. The drainage basin above the dam is 174 square miles of forest and rangeland, much of it within the Fremont National Forest. The land around the reservoir and in the valley upstream is, for the most part, in private ownership. In addition to Drews Creek there are a number of small, intermittent streams that contribute water to the reservoir. Largest of these is Dog Creek, originating in Dog Lake four miles upstream. The outflow is diverted into the North Drews Canal which has been carrying water to irrigated lands west of Lakeview since March 1914.

Fishing at Drews Reservoir has been quite good for rainbow trout and a variety of warm-water species. In an attempt to enhance the fishery, white crappie were introduced in 1975, and channel catfish in 1978. Impediments to fishing are the low water levels in late summer necessitated by irrigation withdrawals and an abundance of rough fish. Visitor facilities include picnic tables, restrooms, and a boat ramp on the southwest side near the dam.

The water quality characteristics of Drews Reservoir are largely influenced by the high concentration of suspended inorganic sediment. Although the reservoir is not very shallow (average depth = 15.9 feet), wind-driven waves nonetheless stir bottom sediments and decrease water transparency (Secchi disk depth = 2.3 feet, or 0.7 meters). The total phosphorus concentration is quite high (0.17 mg/1), and most of it is probably derived from the bottom sediments. Phytoplankton are fairly abundant; McHugh (1972) reported a spring diatom bloom of Synedra ulna, followed in the summer by a bloom of Aphanizomenon flos-aquae. One side of the reservoir is shallow, and despite the water level fluctuations macrophytes are common here. The reservoir is distinctly eutrophic.