- Coos County
- Douglas County)
Eel Lake is a large, deep lake located along the Oregon Coast between the Umpqua River and Coos Bay. Clear, Edna, Teal, Stuttpelz and Hall Lakes drain into the western side of Eel Lake via Clear Creek. Tributaries also include Eel and Marsh Creeks which flow into the east and west arms of the lake. The lake’s outlet, Eel Creek, joins Tenmile Creek about a mile below Tenmile Lake before flowing into the Pacific. Eel Lake, like many other lakes on the Oregon Coast was formed by a series of geological events that included changes in sea level and movement of coastal dunes.
Nearly all the shoreline of Eel Lake drops precipitously to a flat bottom of over eighteen meters deep. The average depth is 12.5 meters and the deepest point is approximately 20 meters. The northern portions of each of the lake’s arms gradually become shallower and end in extensive wetlands.
Eel Lake’s watershed consists of steep timber covered slopes ranging from 16 to 228 meters above sea level. Rainfall within the watershed averages 74 inches per year. There are a few residential areas to the west of the lake, but most of the watershed is owned by private logging interests and William M Tugman State Park. A boat launch, picnic facilities, restrooms, and hiking trails are provided in the State Park. There are no homes on the lakeshore.
The lake is primarily used for fishing, boating, and drinking water supply. The Lakeside Water District uses Eel Lake as a drinking water source for approximately 1200 residents of the City of Lakeside and surrounding areas. Fish species include native cutthroat trout, coho salmon, steelhead, and rainbow trout; and non-native largemouth bass, yellow perch, and bluegill. The Oregon Department of Fish and Wildlife stocks Eel Lake with rainbow trout each spring.
Limited water quality data have been collected from Eel Lake, however, water quality data is available from the PNWWQX for six dates. Data were collected on one date in 1981 for the print version of the Atlas of Oregon Lakes (Johnson 1985); by DEQ on two 1992 dates; and by Portland State University on three 2001 dates. Chlorophyll a concentrations, total phosphorus concentrations, and Secchi transparency measurements indicated that the lake was mesotrophic. Anoxic conditions observed below the thermocline during 1992 and 2001 indicated strong thermal stratification and a supply of organic material sufficient to deplete dissolved oxygen below the thermocline.
Extensive macrophyte beds are present in the shallow northern arms as well the limited shallow depths along the rest of the shoreline. The non-native invasive species Egeria densa is the dominant species in the lake. Other species present include Brasenia schreberi.