Lake

Jefferson County

Deschutes Basin

Location Area 3,916 acres (1,584.8 hect) Elevation 1,945 ft (592.8 m) Type reservoir Use multipurpose Location 6 miles w est-southw est of Madras on Access from Madras and U.S. Hw y 97 via county roads USGS Quad (24K), Madras (100K) Coordinates 44˚ 36' 09" N, 121˚ 16' 52" W USPLSS tow nship 11S, range 12E, section 22

Lake Billy Chinook (also known as Round Butte Reservoir) is the uppermost of two Portland General Electric reservoirs on the Deschutes River. It is located about 100 miles above the confluence of the Deschutes with the Columbia River. Round Butte Dam was completed in 1964 by P.G.E. for hydro-electric power generation. It is an earth and rockfill structure 440 feet high, designed to hold 535,000 acre feet of water and to generate 300,000 kw of electric energy. The dam is named for Round Butte, a prominent topographic feature rising directly to the east. The name Billy Chinook is in honor of a Wasco Indian who joined the John C.

Fremont expedition in 1843 and eventually accompanied the explorer to Washington D.C. Source: National Guard, 1981-82. View looking south. Billy Chinook later became one of the nominal chiefs of the Dalles band of Wascos and in this capacity was a signer of the "Treaty with the Tribes of Middle Oregon, 1855". ` Drainage Basin Characteristics The lake is a very busy recreation site. A huge state park, Cove Palisades, sits astride the Area 7,380.0 sq mi (19,114.2 sq km)Relief steep Precip 10-90 in (25-229 cm ) Deschutes River and the Arms. Several boat launching ramps, a swimming Agriculture beach, and camping and picnicking sites are available in the park and all receive very heavy Land Forest Range Water Irrig Non Irrig Urban Other use. Angling is good for a variety of species. Rainbow trout are stocked heavily and are taken Us e % 45.8 47.1 0.9 4.2 0.2 0.3 1.8 in good numbers as are other trout species such as Dolly Vardon and brown trout. Kokanee Note s Other - Rock outcrops angling has also become quite successful following a stocking program in the 1970s. Power Lake Morphometry M axim um Average boating and water skiing are favorite pastimes during the warm summer months. Area 3,916.0 acres (1,584.8 hect) Depth 415 ft (126.5 m) 102ft (31.1 M) Ave/Max Depth Ratio 0.250 Volume 399,952 acre ft (494.06 cu hm ) The large impoundment drains the entire Deschutes River basin above Round Butte Dam, an Shoal area 5% Volum e factor .74 Shape factor 7.11 area of 7380 square miles ranging from semi-arid rangeland to the forested crest of the Length of Shoreline 62.3 mi (100.3 km) Retention tim e 2 mo Cascades. The lake itself consists essentially of three long, narrow arms where water behind Notes - the dam backs up into the Metolius, Deschutes, and Crooked Rivers. The Metolius arm is 12 miles long and contributes 40 percent of the inflow; the Crooked River arm is six miles long W ater Quality and also contributes 40 percent of the inflow; the Deschutes arm is 8.5 miles long and Trophic status eutrophic, adverse cultural impacts unlikely in future provides the other 20 percent of the inflow. Much of the limnological character of the lake depends upon the water quality characteristics of each river. In general, the Sam ple date 08/24/82 Tem p 58.6F (14.8C) Diss. Oxygen (m g/l) 8.7 which drains forested terrain to the west, supplies water which is cooler, lower in dissolved Transparency 14.8 ft (4.5 m) Phosp (mg/l) 0.032 Cholorophyl a (mg/l) 2.3 minerals, and much less turbid. The Crooked River drains an area with extensive pasture and Alkalinity 80 Conductivity (umhos/cm) 164 pH 9.4 agriculture land. Water from this drainage basin contains a higher concentration of dissolved Major Na K Ca Mg Cl SO4 minerals, is warmer in the summer, and frequently carries a substantial load of silt. The Ions 13.5 2.5 9.9 7.1 2.9 5.2 Deschutes River water is generally intermediate in character and receives the greatest Notes - influence from human development. Each major inlet contributes relatively high concentrations of major ions to the lake. Much of the drainage basins of the Crooked and Sam ple date 05/21/82 Tem p 58.6F (14.8C) Diss. Oxygen (m g/l) 12.2 Deschutes Rivers are in semi-arid climates where evaporation concentrates the major ions, Transparency 7 ft (2.0 m) Phosp (mg/l) 0.056 Cholorophyl a (mg/l) 6.0 and the main source of Metolius River water is from ground water which contains high Alkalinity 84 Conductivity (umhos/cm) 171 pH 8.8 concentrations of major ions. Similarly, phosphorus concentrations are high in the inlets Major Na K Ca Mg Cl SO4 (including the Metolius) and throughout the entire lake. Ions 13.9 2.4 12.0 7.0 2.5 6.0 Notes - Water transparencies in are influenced primarily by the amount of 11/05/82 53.6F (12.0C) sediment entering the lake from the three rivers, and less so by the densities of Sam ple date Tem p Diss. Oxygen (m g/l) 12.8 21.8 phytoplankton. The lowest transparency value in this survey of 3.6 feet (1.1 meters) was Transparency 13 ft (4.0 m) Phosp (mg/l) 0.046 Cholorophyl a (mg/l) recorded in the Crooked River arm, followed by 6.6 feet (2.0 meters) near the dam, 8.5 feet Alkalinity 84 Conductivity (umhos/cm) 170 pH 9.10 (2.6 meters) in the Deschutes arm, and 19.7 feet (6.0 meters) in the Metolius arm. In contrast, Major Na K Ca Mg Cl SO4 the highest value recorded by Mullarkey (1967) was 40 feet (12.2 meters) in the Metolius Ions 14.8 2.4 10.7 7.0 7.4 4.4 Notes arm; his lowest was 0.3 feet (0.1 meters) in the Crooked River arm. Seasonally, water transparency was lowest in the spring in the 1982 survey: a value of 6.6 feet (2.0 meters) was noted at the sample site behind the dam on 5/21/82, in comparison to 14.8 feet (4.5 meters) in summer, and 13 feet (4.0 meters) in autumn. Dissolved oxygen in the reservoir ranges from 0 to super saturated (maximum observed D.O. was 16 ppm). The lowest dissolved oxygen summer, a light bloom of Aphanizomenon was visibly present, but was neither objectionable occurs in the silt laden hypolimnion of the Crooked River arm. In the epilimnion, and in the nor a deterrent to water contact sports. Phytoplankton samples were collected from sites near Metolius arm in general, dissolved oxygen remains at 6ppm or higher, more than adequate each major inlet (within the reservoir) in May 1982. Each sample, although similar in that for salmonid fish. The lake stratified in the summer of 1982, with a thermocline at about 23 each consisted of periphytic algae (algae growing "attached" to a substrate), contained a feet (7 meters). The surface water temperature reached 70 degrees Fahrenheit (21 degrees different assemblage of algal species. The algae near the dam were different from the algae at Celsius) at this time, favoring water skiing and swimming activities. During stratification, each inlet, and contained true planktonic species. Macrophytes are scarce in Lake Billy only a moderate depletion of hypolimnetic dissolved oxygen occurred. Chinook due to the very steep littoral areas and the rocky substrate. Overall, the trophic state of this lake is eutrophic, but at the lower end of the spectrum. Because of the basin The phytoplankton species clearly indicate eutrophic conditions; however, their densities are morphometry (steep shores and large volume), and because the phosphorus concentration is lower than might be predicted from the high nutrient concentrations and warm water already quite high, it is unlikely that future increases in recreational activities would temperatures. The predominant algal species (near the dam) during the spring were eutrophic adversely affect the water quality. diatoms(Stephanodiscus, Asterionella, Fragilaria) and the flagellate Cryptomonas. During

48 Atlas of Oregon Lakes

Source: US Forest Service, 1972. Vertical photograph.

Lake Reports 49