Antelope Flat Reservoir
- Crook County)
(From Atlas of Oregon Lakes, Johnson et al. 1985). Antelope Flat Reservoir is an irrigation impoundment on the south side of the Maury Mountains in Central Oregon. It is situated near the headwaters of Bear Creek, a tributary of the Crooked River, and was formed by a 33-foot high earthfill dam at the west end of Antelope Flat. Antelope Flat is the name given the dish-shaped valley that supports an exceptional variety of vegetation, from grassy sagebrush on the lower slopes to sparse juniper stands and pine forest at the higher elevations. The reservoir has a storage capacity of nearly 2000 acre-feet and a surface area of 170 acres when full; but it is often drawn down to less than half that size by late summer to satisfy downstream irrigation needs. Rainbow trout are found in the reservoir and there have been reports of a high growth rate and good success by anglers. Recreation facilites have been provided near the dam, including a good paved boat ramp. There is no campground at the reservoir, but a good one nearby.
The maximum depth of the reservoir is 28 feet at full pool and the average depth is only 11 feet. The water is frequently turbid because of the growth of phytoplankton and because of bank erosion caused by surface waves, thus decreasing water transparency. The concentration of ions is fairly high, characteristic of the semi-arid Crooked River drainage. Alkalinity and conductivity are above average for eastern Oregon reservoirs. The concentration of phosphorus is very high, and chlorophyl is above average. Macrophytes grow in all of the littoral zone, especially at the swampy area near the inflow at the east end of the reservoir. Because of the combination of shallow water and a significant supply of nutrients from the drainage basin, Antelope Flat Reservoir is distinctly eutrophic.