Description - The Potholes Reservoir is part of the Columbia Basin Project and formed by O'Sullivan Dam. Potholes refers to the many glacial depressions in ancient sand dunes here. These potholes and small islands make this area one of the best in Washington for birding.
- Potholes Reservoir is open year-round. Developed campsites are available at Mardon Resort; (509)346-2651. Access to the reservoir is adequate except that the west side is limited. Fish species include yellow perch, crappie, largemouth bass, rainbow trout, and walleye.
Recreation - Fishing activities are available at Potholes Reservoir year-round and camping is available nearby. Hiking and hunting are also available. There are picnick sites and wildlife viewing is good.
Climate - The climate of Washington varies within each region. The Cascades split the state and alter the weather patterns. The mountains receive large amounts of wet, heavy snow from October through May. These peaks remain snow covered throughout the year. The terrain east of the mountains receives approximately 12 inches of rainfall per year, generally much less than west of the mountains. Since the area east of the mountains is landlocked, temperatures in this region are lower during the winter months. Frequent winds coming down from the mountains also contribute to the low temperatures of eastern Washington.
Due to the coastal geography, western Washington is primarily temperate. The proximity to the ocean stabilizes the climate, making extreme temperatures very rare. The area receives large amounts of precipitation from Pacific rain and snow storms.
Potholes Reservoir is located 15 miles south of Moses Lake off State Rt. 262. A map is available above on this wildernet page.