Boise River
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The Boise River is a tributary of the Snake River, approximately 75 mi (121 km) long, in southwestern Idaho in the United States. It drains a rugged portion of the Sawtooth Range northeast of Boise, as well as part of the western Snake River Plain. The watershed encompasses approximately 4100 sq mi (10600 sq km) of highly diverse habitats, including alpine canyons, forest, rangeland, agricultural lands, and urban areas.
Description
It rises in three separate forks in the Sawtooth Range above an elevation of 10,000 ft (3000 m) and is formed by the confluence of its North and Middle forks. The North Fork (approximately 50 mi/80 km long) rises in the Sawtooth Wilderness Area, along the Boise-Elmore county line, approximately 60 mi (100 km) northeast of Boise. It flows generally southeast through the remote mountains in the Boise National Forest. The Middle Fork (approximately 70 mi/113 km SW long) rises within 20 mi (32 km) of the North Fork in the southern Sawtooth Wilderness Area in northeastern Elmore County. It flows WSW, joining the North Fork to form the Boise approximately 15 mi (24 km) southeast of Idaho City. The main stream flow southwest through Arrow Rock Reservoir before receiving the South Fork.
The South Fork (100 mi/161 km) rises rises in northern Camas County in the Sawtooth National Forest, approximately 60 mi (100 km) east of Boise. It flows generally southwest, descending through a basalt canyon and passing through the Anderson Ranch Reservoir, then turns northwest in central Elmore County. It joins the main stream from the south as an arm of Arrow Rock Reservoir approximately 20 mi (32 km) east of Boise to form the main stream.
Downstream from its confluence with the South Fork the river flows generally WNW, passing through Lucky Peak Reservoir and emerging from the foothills at Boise. It passes through downtown Boise, lined by an extensive recreational greenbelt, then flows northwest across the western end of the Snake River Plain, becoming a braided stream with a wide floodplain as it approaches the Snake. It enters the Snake from the east on the Idaho-Oregon border approximately 3 mi (5 km) south of Nyssa, Oregon.
History
The river was called "Reed's River" in the early 19th century. It was explored during 1811 Astorian Expedition. The river is used for irrigation on the plain east of Boise. The dams that form the mountain reservoirs were constructed as part of the Boise Project to provide hydroelectricity, drinking water, and flood control to Boise and the surrounding area.
The river is a popular destination for floating and whitewater rafting. On the lower (warmwater) course of the river, low summer flows and poorer water quality from agricultural runoff limit fishery production. This section of river supports a fair fishery for largemouth bass, smallmouth bass, and channel catfish. Upstream from Star, the river is a coldwater stream and supports a greater variety of fish. The most prevalent species on this section is mountain whitefish, as well as hatchery-reared rainbow trout, wild rainbow trout, and fingerling brown trout. Upstream from Lucky Peak and Arrowrock reservoirs, the river and its tributaries contain excellent populations of wild rainbow trout, mountain whitefish, and bull trout. This is especially true immediately downstream from the outflow of Anderson Ranch reservoir, where the South Fork takes on the characteristics of a classic "tailwater" for over five miles from the put-in below the dam to Cow Creek Bridge.
External links
- State of Idaho: Boise River (http://www.idwr.state.id.us/tvalley/Boise_River.htm)
- Idaho State University: Boise River (http://imnh.isu.edu/digitalatlas/geog/fishery/drainage/drain20.htm)