| Boise River | |
|---|---|
 | |
 The Boise River watershed | |
| Location | |
| Country | United States |
| State | Idaho |
| Physical characteristics | |
| Source | Sawtooth Range |
| • location | Idaho |
| • coordinates | 43°42′48″N115°38′9″W / 43.71333°N 115.63583°W /43.71333; -115.63583[1] |
| • elevation | 3,497 ft (1,066 m) |
| Mouth | Snake River |
• location | Idaho |
• coordinates | 43°49′15″N117°1′34″W / 43.82083°N 117.02611°W /43.82083; -117.02611[1] |
• elevation | 2,100 ft (640 m) |
| Length | 102 mi (164 km)[2] |
| Basin size | 4,100 sq mi (11,000 km2) |
| Discharge | |
| • location | Parma, about 3.8 mi (6.1 km) from the mouth |
| • average | 1,587 cu ft/s (44.9 m3/s) |
| • minimum | 66 cu ft/s (1.9 m3/s) |
| • maximum | 9,140 cu ft/s (259 m3/s) |
TheBoise River is a 102-mile-long (164 km)[2]tributary of theSnake River in theNorthwestern United States. It drains a rugged portion of theSawtooth Range in southwesternIdaho northeast ofBoise, as well as part of the westernSnake River Plain. The watershed encompasses approximately 4,100 square miles (11,000 km2) of highly diverse habitats, including alpine canyons, forest, rangeland,agricultural lands, and urban areas.
The Boise River rises in three separate forks in the Sawtooth Range atelevations exceeding 10,000 feet (3,050 m), and is formed by the confluence of its North and Middle forks. The North Fork, 50 miles (80 km) long,[2] rises in theSawtooth Wilderness Area, along theBoise–Elmore county line, 60 miles (100 km) northeast of Boise. It flows generally southwest through the remote mountains in theBoise National Forest. The Middle Fork, approximately 52 miles (84 km) in length,[2] rises within 12 miles (19 km) of the North Fork in the southern Sawtooth Wilderness Area in northeastern Elmore County. It flows west-southwest near the town ofAtlanta, joining the North Fork to form the Boise River, approximately 15 miles (24 km) southeast ofIdaho City. The main stream flows southwest intoArrowrock Reservoir, joining the South Fork from theAnderson Ranch Dam.
The 101-mile-long (163 km)[2] South Fork rises in northernCamas County in theSmoky Mountains andSoldier Mountains of theSawtooth National Forest north ofFairfield, 65 miles (105 km) east of Boise. It flows generally southwest, descending through abasalt canyon to fill theAnderson Ranch Reservoir, then turns northwest in central Elmore County. It joins the main stream as the southern arm of Arrowrock Reservoir, 20 miles (32 km) east of Boise.
Downstream from its confluence with the South Fork, the river flows generally west, adds the major tributary of Mores Creek alongHighway 21, and passes throughLucky Peak Dam to emerge from the foothills southeast of Boise. It passes over several irrigation diversion dams above the city, the first and largest is the century-oldBoise River Diversion Dam for the concrete New York Canal, which terminates atLake Lowell (a.k.a.Deer Flat Reservoir) southwest ofNampa inCanyon County.[3] The next diversion is for the Ridenbaugh Canal (1878)[4][5] at Eckert Diversion Dam, immediately above Barber Park, five miles (8 km) from downtown Boise.[6] Wooded through the city, the river is lined by an extensive recreationalgreenbelt. It flows west across the western end of the Snake River Plain in theTreasure Valley and becomes abraided stream with a widefloodplain as it crosses northernCanyon County to theSnake River. At an approximate elevation of 2,100 feet (640 m), it enters the Snake River, the Idaho-Oregon border, west ofParma and three miles (5 km) south ofNyssa,Oregon.
The river was called "Reed's River" in the early 19th century, named afterPacific Fur Company employeeJohn Reed, who explored parts of the river throughout 1813 and 1814. The river is diverted to canals forirrigation on the plain west of what is now Boise. The dams that form the mountain reservoirs were constructed as part of theBureau of Reclamation's "Boise Project" to provide agricultural irrigation,hydroelectricity, drinking water, andflood control to Boise and theTreasure Valley.[7]
The major projects' initial completion dates were:
The Boise River was proposed for 50 years for a dam at Twin Springs, culminating in a 1966Project Travois proposal, which would have used nuclear explosives to either create large amounts of rockfill aggregate for dam construction, or to induce a landslide that would have much the same effect. Project Travois was a component ofProject Plowshare. The project was abandoned in 1968 after concerns were raised about radiological contamination, and the seismic safety of downstream dams.[8][9]
The river is a popular destination for floating, specifically on theBoise greenbelt.Tubers and floaters launch at Barber Park[10] and land at Ann Morrison Park, between major irrigation diversion dams.[11] Several minor diversion weirs are passed as well as several bridges on the 6-mile (10 km) trip.[6]Water skiing is popular above the dam at the Lucky Peak Reservoir.[citation needed]
On the lower (warmwater) course of the river, low summer flows and poorer water quality from agricultural runoff limitfishery production. This section of river supports a fair fishery forlargemouth bass, smallmouth bass, and channelcatfish. Upstream fromStar, the river is a coldwater stream and supports a greater variety of fish. The most prevalent species on this section ismountain whitefish, as well as hatchery-rearedrainbow trout, wild rainbow trout, and fingerlingbrown 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 5 miles (8 km) from the put-in below the dam to Cow Creek Bridge.[citation needed]
The Boise River is also popular forfishing, mostly forrainbow trout and, in the winter,steelhead. Spin-fishermen use roostertail spinners andbait such asworms and Powerbait, whilefly fishermen use a variety of flies mimicking the abundant aquatic and terrestrial insects present in the watershed, as well as streamers.[citation needed]
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