Wolf Creek Reservoir (Union)
Reachcode: 17050203006039 | Area: 195.0 acres | Shoreline: 3.4 mi | View on Interactive Map
(From Atlas of Oregon Lakes, Johnson et al. 1985). Wolf Creek Reservoir is a fairly new irrigation impoundment in northeastern Oregon located on Wolf Creek, a tributary of the Powder River. It serves to regulate flows into the larger Thief Valley Reservoir downstream on the Powder River. The reservoir lies in a triangular shaped basin oriented east-west with the dam located at the eastern end. It is mostly surrounded by grassland but there are small patches of forest at the upper end around the inflowing stream. There are also several prominent rocky outcrops at the western end of the reservoir. The upper portion of the drainage basin lies within the Wallowa-Whitman National Forest. Fish are routinely planted and the reservoir is a popular fishing spot. There is an excellent boat ramp which allows boat launching even when the reservoir is drawn down in late summer. Picnic tables with wind and sun screens are available above the reservoir.
The concentrations of minerals in the reservoir are low in spite of the relatively arid climate. The concentration of phosphorus is moderate and supports the growth of phytoplankton, including occasional blooms of blue-green algae. There is very little macrophyte growth. The pH of the water is somewhat above neutrality because of phytoplankton growth. The reservoir is drawn down extensively in late summer by irrigation withdrawals, exposing muddy banks around the reservoir. Water transparency is limited, partially because of the phytoplankton but also because of some erosion from the exposed shoreline during drawdown. The reservoir is classified at the lower end of eutrophy.