The Boise River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. , accessed May 3, 2011

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainage ...

of the

Snake River The Snake River is a major river of the greater Pacific Northwest region in the United States. At long, it is the largest tributary of the Columbia River, in turn, the largest North American river that empties into the Pacific Ocean. The Snake ...

in the

Northwestern United States The Northwestern United States, also known as the American Northwest or simply the Northwest, is an informal geographic region of the United States. The region consistently includes the states of Oregon, Washington, Idaho, Montana and Wyoming. ...

. It drains a rugged portion of the Sawtooth Range in southwestern

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...

northeast of

Boise Boise (, , ) is the capital and most populous city of the U.S. state of Idaho and is the county seat of Ada County. On the Boise River in southwestern Idaho, it is east of the Oregon border and north of the Nevada border. The downtown area' ...

, as well as part of the western

Snake River Plain image:Snake River view near Twin Falls, Idaho.jpg, The Snake River cutting through the plain leaves many canyons and Canyon#List of gorges, gorges, such as this one near Twin Falls, Idaho The Snake River Plain is a geology, geologic feature ...

. The watershed encompasses approximately of highly diverse habitats, including alpine canyons, forest, rangeland,

agricultural Agriculture or farming is the practice of cultivating Plant, plants and livestock. Agriculture was the key development in the rise of Sedentism, sedentary human civilization, whereby farming of Domestication, domesticated species created food ...

lands, and urban areas.

Description

The Boise River rises in three separate forks in the Sawtooth Range at

elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Vert ...

s exceeding , and is formed by the confluence of its North and Middle forks. The North Fork, long, rises in the Sawtooth Wilderness Area, along the

– Elmore county line, northeast of Boise. It flows generally southwest through the remote mountains in the

Boise National Forest Boise National Forest is a National Forest covering of the U.S. state of Idaho. Created on July 1, 1908, from part of Sawtooth National Forest, it is managed by the U.S. Forest Service as five units: the Cascade, Emmett, Idaho City, Low ...

. The Middle Fork, approximately in length, rises within of the North Fork in the southern Sawtooth Wilderness Area in northeastern Elmore County. It flows west-southwest near the town of

Atlanta Atlanta ( ) is the capital and most populous city of the U.S. state of Georgia. It is the seat of Fulton County, the most populous county in Georgia, but its territory falls in both Fulton and DeKalb counties. With a population of 498,715 ...

, joining the North Fork to form the Boise River, approximately southeast of

Idaho City Idaho City is a city in and the county seat of Boise County, Idaho, Boise County, Idaho, United States, located about northeast of Boise, Idaho, Boise. The population was 485 at the 2010 United States Census, 2010 census, up from 458 in 2000. ...

. The main stream flows southwest into

Arrowrock Reservoir Arrowrock Dam is a concrete arch dam in the western United States, on the Boise River in southwestern Idaho, east of Boise. Opened in 1915, it is located on the border of Boise and Elmore counties, upstream of the Lucky Peak Dam and reservoi ...

, joining the South Fork from the

Anderson Ranch Dam Anderson Ranch Dam is an earth rockfill type dam in the western United States, on the South Fork of the Boise River in southwestern Idaho. In Elmore County northeast of Mountain Home, it is several miles north of U.S. Route 20 ...

. The South Fork rises in northern Camas County in the

Smoky Mountains The Great Smoky Mountains (, ''Equa Dutsusdu Dodalv'') are a mountain range rising along the Tennessee– North Carolina border in the southeastern United States. They are a subrange of the Appalachian Mountains, and form part of the Blue Ri ...

and

Soldier Mountains The Soldier Mountains are a mountain range in the U.S. state of Idaho, spanning northern Camas and eastern Elmore counties. The highest point in the range is Smoky Dome at , and the range is bounded on the west and north by the South Fork Boi ...

of the

Sawtooth National Forest Sawtooth National Forest is a National Forest that covers 2,110,408 acres (854,052 ha) in the U.S. states of Idaho (~96 percent) and Utah (~4 percent). Managed by the U.S. Forest Service in the U.S. Department of Agriculture, it was originally ...

north of Fairfield, east of Boise. It flows generally southwest, descending through a

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

canyon to fill the Anderson Ranch Reservoir, then turns northwest in central Elmore County. It joins the main stream as the southern arm of Arrowrock Reservoir, east of Boise.

Downstream from its confluence with the South Fork, the river flows generally west, adds the major tributary of Mores Creek along Highway 21, and passes through

Lucky Peak Dam Lucky Peak Dam is a rolled earth and gravel fill embankment dam in the western United States, located on the Boise River in southwestern Idaho. In Ada County east of Boise, it is directly downstream of Arrowrock Dam, a concrete arch dam com ...

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-old

Boise River Diversion Dam The Boise River Diversion Dam is a diversion dam in the western United States, on the Boise River in southwestern Idaho. southeast and upstream of Boise in Ada County, it was completed in 1909 and is operated by the U.S. Bureau of Reclamat ...

for the concrete New York Canal, which terminates at

Lake Lowell Deer Flat Upper Embankment (National ID # ID00276) is a dam in the western United States in southwestern Idaho. Located in the Treasure Valley in Canyon County, it is directly southwest of Nampa. The earthen dam was completed in 1908 by th ...

(a.k.a. Deer Flat Reservoir) southwest of Nampa in Canyon County. The next diversion is for the Ridenbaugh Canal (1878) at Eckert Diversion Dam, immediately above Barber Park, five miles (8 km) from downtown Boise. Wooded through the city, the river is lined by an extensive recreational

greenbelt A green belt is a policy and land-use zone designation used in land-use planning to retain areas of largely undeveloped, wild, or agricultural land surrounding or neighboring urban areas. Similar concepts are greenways or green wedges, which h ...

. It flows west across the western end of the Snake River Plain in the

Treasure Valley The Treasure Valley is a valley in the western United States, primarily in southwestern Idaho, where the Payette, Boise, Weiser, Malheur, Owyhee, and Burnt rivers drain into the Snake River. It includes all the lowland areas from Vale in rur ...

and becomes a

braided stream A braided river, or braided channel, consists of a network of river channels separated by small, often temporary, islands called braid bars or, in English usage, '' aits'' or ''eyots''. Braided streams tend to occur in rivers with high sediment ...

with a wide

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river which stretches from the banks of its channel to the base of the enclosing valley walls, and which experiences flooding during periods of high discharge.Goudi ...

as it crosses northern Canyon County to the

. At an approximate elevation of , it enters the Snake River, the Idaho-

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

border, west of

Parma Parma (; egl, Pärma, ) is a city in the northern Italian region of Emilia-Romagna known for its architecture, Giuseppe Verdi, music, art, prosciutto (ham), Parmigiano-Reggiano, cheese and surrounding countryside. With a population of 198,292 ...

and three miles (5 km) south of Nyssa,

History

The river was called "Reed's River" in the early 19th century, named after

Pacific Fur Company The Pacific Fur Company (PFC) was an American fur trade venture wholly owned and funded by John Jacob Astor that functioned from 1810 to 1813. It was based in the Pacific Northwest, an area contested over the decades between the United Kingdom o ...

employee John Reed, who explored parts of the river throughout 1813 and 1814. The river is diverted to canals for

irrigation Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...

on the plain west of Boise. The dams that form the mountain reservoirs were constructed as part of the Bureau of Reclamation's "Boise Project" to provide agricultural irrigation,

hydroelectricity Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other Renewabl ...

, drinking water, and

flood A flood is an overflow of water ( or rarely other fluids) that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are an area of study of the discipline hydrol ...

control to Boise and the

. The major projects' initial completion dates were: * 1909 –

& New York Canal * 1915 –

Arrowrock Dam Arrowrock Dam is a concrete arch dam in the western United States, on the Boise River in southwestern Idaho, east of Boise. Opened in 1915, it is located on the border of Boise and Elmore counties, upstream of the Lucky Peak Dam and reservoir. ...

* 1950 –

- (S. Fork) * 1955 –

- (

U.S. Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cl ...

Corps of Engineers)

Recreation

The river is a popular destination for floating, specifically on the

Boise greenbelt The Boise River Greenbelt is a recreational and alternate transportation trail along the banks of the Boise River through Boise, Idaho, United States. The Boise Greenbelt is more of a greenway than a green belt since its character is linear. ...

Tubers Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing s ...

and floaters launch at Barber Park and land at Ann Morrison Park, between major irrigation diversion dams. Several minor diversion weirs are passed as well as several bridges on the trip.

Water skiing Water skiing (also waterskiing or water-skiing) is a surface water sport in which an individual is pulled behind a boat or a cable ski installation over a body of water, skimming the surface on two skis or one ski. The sport requires suffic ...

is popular above the dam at the Lucky Peak Reservoir. On the lower (warmwater) course of the river, low summer flows and poorer water quality from agricultural runoff limit

fishery Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both ...

production. This section of river supports a fair fishery for

largemouth bass The largemouth bass (''Micropterus salmoides'') is a carnivorous freshwater gamefish in the Centrarchidae ( sunfish) family, a species of black bass native to the eastern and central United States, southeastern Canada and northern Mexico, but ...

, smallmouth bass, and channel

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, ...

. Upstream from

Star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

, the river is a coldwater stream and supports a greater variety of fish. The most prevalent species on this section is

mountain whitefish The mountain whitefish (''Prosopium williamsoni'') is one of the most widely distributed salmonid fish of western North America. It is found from the Mackenzie River drainage in Northwest Territories, Canada south through western Canada and t ...

, as well as hatchery-reared

rainbow trout The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead (sometimes called "steelhead trout") is an anadromous (sea-run) form of the coasta ...

, wild rainbow trout, and fingerling

brown trout The brown trout (''Salmo trutta'') is a European species of salmonid fish that has been widely introduced into suitable environments globally. It includes purely freshwater populations, referred to as the riverine ecotype, ''Salmo trutta'' morph ...

. 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 from the put-in below the dam to Cow Creek Bridge.

Fishing

The Boise River is also popular for

fishing Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from stocked bodies of water such as ponds, canals, park wetlands and reservoirs. Fishing techniques inclu ...

, mostly for

and, in the winter,

steelhead Steelhead, or occasionally steelhead trout, is the common name of the anadromous form of the coastal rainbow trout or redband trout (O. m. gairdneri). Steelhead are native to cold-water tributaries of the Pacific basin in Northeast Asia and N ...

. Spin-fishermen use roostertail spinners and bait such as

worm Worms are many different distantly related bilateral animals that typically have a long cylindrical tube-like body, no limbs, and no eyes (though not always). Worms vary in size from microscopic to over in length for marine polychaete wor ...

s and Powerbait, while fly fishermen use a variety of flies mimicking the abundant aquatic and terrestrial insects present in the watershed, as well as streamers.

References

External links