Arrowrock Dam is a concrete
arch
An arch is a vertical curved structure that spans an elevated space and may or may not support the weight above it, or in case of a horizontal arch like an arch dam, the hydrostatic pressure against it.
Arches may be synonymous with vault ...
dam
A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, a ...
in the
western
Western may refer to:
Places
*Western, Nebraska, a village in the US
*Western, New York, a town in the US
*Western Creek, Tasmania, a locality in Australia
*Western Junction, Tasmania, a locality in Australia
*Western world, countries that id ...
United States, on the
Boise River
The Boise River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. , accessed May 3, 2011 tributary of the Snake River in the Northwestern United States. It drains a rugged portion of the Sawtooth Range in sou ...
in
southwestern
The points of the compass are a set of horizontal, radially arrayed compass directions (or azimuths) used in navigation and cartography. A compass rose is primarily composed of four cardinal directions—north, east, south, and west—each sep ...
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 Wyomi ...
, east 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' ...
. Opened in 1915, it is located on the border 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' ...
and
Elmore counties, upstream of the
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 ...
and reservoir. The spillway
elevation for Arrowrock is above
sea level and its primary purpose is to provide
irrigation water for agriculture.
The dam was designated as a
National Historic Civil Engineering Landmark by the
American Society of Civil Engineers
American(s) may refer to:
* American, something of, from, or related to the United States of America, commonly known as the "United States" or "America"
** Americans, citizens and nationals of the United States of America
** American ancestry, pe ...
in 2016, and is operated by the
U.S. Bureau of Reclamation
The Bureau of Reclamation, and formerly the United States Reclamation Service, is a federal agency under the U.S. Department of the Interior, which oversees water resource management, specifically as it applies to the oversight and opera ...
.
Preparations
In 1910, the
Reclamation Service began to consider another storage facility farther east on the
Boise River
The Boise River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. , accessed May 3, 2011 tributary of the Snake River in the Northwestern United States. It drains a rugged portion of the Sawtooth Range in sou ...
. After several surveys, engineers decided upon the Arrowrock site which had previously been the site of a private irrigation venture under the direction of
Arthur De Wint Foote
Arthur De Wint Foote (1849–1933) was an American civil engineer and mining engineer who impacted the development of the American West with his innovative engineering works and entrepreneurial ventures. In Northern California in the late 189 ...
yet failed for lack of funding.
The Arrowrock site is at the confluence of the main channel and the south fork. That was to be the most ambitious project to date for Reclamation. At , Arrowrock would be the largest
concrete arch dam
An arch dam is a concrete dam that is curved upstream in plan. The arch dam is designed so that the force of the water against it, known as hydrostatic pressure, presses against the arch, causing the arch to straighten slightly and strengthen ...
in the world. Prior to construction, considerable preparatory work would need to be completed. As the structure was some upstream from the
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 ...
, routing supplies to the worksite would be a massive undertaking unto itself. The Reclamation Service elected to construct a new rail line on the old wagon road leading north to
Idaho City. The railroad would begin at the Barberton mill near the Diversion Dam and extend to through a winding canyon up to Arrowrock. Even before the dam had been approved, Reclamation began work on the rail line.
Some significant problems existed with construction of the railroad. The Barberton Lumber Company owned the road's right-of-way. That meant that the Reclamation Service needed to come to an agreement over ownership of the rail line. In an unprecedented move, the government agreed to lease the track from Barberton but run the actual locomotive. Part of this agreement stipulated that the line would remain a common carrier. That made the Arrowrock & Boise Railroad the first publicly owned line in the nation. The Service hid this fact from President
William Howard Taft when it applied for the Arrowrock Dam's approval. Fortunately for Reclamation, Taft failed to recognize the loophole and in June 1910, the entire project went forward. However, when the
Oregon Shortline refused to honor the pact between Barberton and Reclamation, the Arrowrock & Boise terminal was reduced to a field just outside the Barber lumberyard. On August 22, 1910, the entire deal was finalized and work began on the line to the Arrowrock site.
Salt Lake City
Salt Lake City (often shortened to Salt Lake and abbreviated as SLC) is the capital and most populous city of Utah, United States. It is the seat of Salt Lake County, the most populous county in Utah. With a population of 200,133 in 2020, t ...
's Manly Brothers won the contract for grading the Arrowrock & Boise road in May 1911. The government called for
force account
In physics, a force is an influence that can change the motion of an Physical object, object. A force can cause an object with mass to change its velocity (e.g. moving from a Newton's first law, state of rest), i.e., to accelerate. Force can ...
to lay the track from Barber to the work site. Although the construction was delayed several times by the shortage of railroad ties, workers finished the track in early November. By most accounts, the trip through the canyon was a very long and harrowing event. For the first several months, riders were asked to disembark at the unfinished Gooseneck Bridge while the cars were winched across one at a time.
However, once they arrived, most passengers were surprised by what they found. Not only was the view breathtaking but the "work" camp offered amenities that were unavailable to some residents of the Treasure Valley. Not only was the site fully powered, but also it provided a central heating plant, running water and an efficient sewage system. Along with the Reclamation offices, the Arrowrock camp carried a hospital, mess hall, post office, and hotel. Workers and visitors were offered lodging in the site's hotel, bunkhouses, or cottages. In addition to the outdoor recreational activities, the camp also operated a
YMCA
YMCA, sometimes regionally called the Y, is a worldwide youth organization based in Geneva, Switzerland, with more than 64 million beneficiaries in 120 countries. It was founded on 6 June 1844 by George Williams in London, originally ...
, school, and dancehall. At the peak of construction, some 1,400 people had called Arrowrock home, including some 200 families.
To provide power for the site, Reclamation retrofitted The Boise River Diversion Dam with a small powerhouse. Finished in 1912, the plant's three generators produced 1,500 kilowatts of electricity for Arrowrock's camp, sawmills, and giant cement mixers. The German made Allis-Chalmers turbines, the first in the world to be built with a vertical shaft design. Along with the power lines, government forces hung a two-way phone cable to connect Arrowrock with the outside world. In 1976, the power plant was added to the
National Register of Historic Places. After being refurbished by the
Bonneville Power Administration
The Bonneville Power Administration (BPA) is an American federal agency operating in the Pacific Northwest. BPA was created by an act of Congress in 1937 to market electric power from the Bonneville Dam located on the Columbia River and to constr ...
in 2002, it is now on ready reserve status and occasionally provides surplus power during times of peak demand. Special care was made to maintain the historic qualities of the powerhouse. The original governors, slate control panels, transformers, overhead crane, and generator housings, although no longer functional, were retained for historic purposes.
Work commencement
Work began on the Arrowrock Dam in early 1912 and moved along at a record-setting pace. As labor was becoming more plentiful with the completion of
Deer Flat and the Diversion Dam, wage rates began to decrease. Common laborers were now offered $2.40 and day while
skilled workers pulled in anywhere from $3.00 to $4.00. In addition, several deductions were made for room and board. Workers could choose between the dormitory style bunkhouses at $1.25 a month or a private room at $4.00. Seventy-five cents was deducted each day for meals and $1.00 a month went towards hospital costs. The work proved moderately dangerous and accounted for numerous injuries and twelve deaths. However, despite the hazards and reduction in pay, it appears there was a unique level of camaraderie at the Arrowrock site. As stated above, the workers set several construction records, not the least of which included the of concrete laid on the dam.
The Reclamation Service spared no expense regarding the equipment at Arrowrock Dam. Along with the refurbished 70-ton Atlantic steam shovel from Deer Flat were two versatile 18-ton "dinkey" excavators and several brand new dump cars. The cement mixers produced over 2,000 barrels per day and ran uninterrupted for almost 30 months. Two 12-ton Lidgerwood cableways hovered over the site and moved material and concrete from their loading grounds to the dam site. Scores of horse teams helped carry equipment and gravel from the camp to the various work areas. Additionally, one
Buick
Buick () is a division of the American automobile manufacturer General Motors (GM). Started by automotive pioneer David Dunbar Buick in 1899, it was among the first American marques of automobiles, and was the company that established General M ...
and seven
Ford
Ford commonly refers to:
* Ford Motor Company, an automobile manufacturer founded by Henry Ford
* Ford (crossing), a shallow crossing on a river
Ford may also refer to:
Ford Motor Company
* Henry Ford, founder of the Ford Motor Company
* Ford F ...
trucks serviced both crews and visitors and provided an unexpected level of mobility throughout the campsite. In an effort to alleviate some of the discomfort along the Boise & Arrowrock, Reclamation purchased a 60-ton locomotive and several new passenger cars. For almost five years, the train ran faithfully through the canyon, delivering over 89,500 visitors and crewmen. Also, during its commission, the Boise & Arrowrock traveled more than and carried 14,000,000 tons of freight.
Dedication
On October 4, 1915, the Arrowrock Dam was finally dedicated. As stated above, it was the tallest dam in the world for nine years, until the completion of the
Schräh dam in
Switzerland in 1924, with a height of . In addition, engineers pioneered the use of dam instrumentation with the placement of ten thermometers embedded deep within the structure's concrete. Along with innovative contraction joints, the Reclamation Service was able to control the temperature of the setting concrete, ensuring the dams strength. It is thick at the base and thick at the crest. It is serviced by 25 outlets some of which are designed to regulate themselves, another first in engineering. Ten outlets were built for an eventual power plant, but they have yet to be used.
In total, the dam contains of concrete and the reservoir holds over of irrigation water. Within the first week of operation, an estimated 12,000 visitors braved the canyon ride to see the dam. However, as interest waned, the Arrowrock & Boise Railroad schedule dropped significantly. The campsite, once a bustling hive of activity, was quickly becoming a
ghost town. On August 11, 1916, the government decommissioned its very first public carrier.
Later work
From 1935 to 1937, construction at Arrowrock raised the dam , increasing its capacity by , and replaced deteriorating concrete on the dam's downstream face and spillway channel.
From 2001 to 2004, ten aging Ensign valves were removed and replaced with clamshell gates. By 2011, work was completed to permanently plug all five sluice gate outlets.
A 15-MW powerplant was added to Arrowrock Dam in March 2010, and the transmission line to the dam was updated.
See also
*
List of dams and reservoirs in Idaho
This is a list of dams and reservoirs in the U.S. state of Idaho.
See also
* List of lakes of Idaho
* List of dams in the Columbia River watershed
* List of dam removals in Idaho
{{Idaho
Idaho
Idaho ( ) is a state in th ...
- 4th largest in Idaho
*
List of lakes in Idaho
*
List of dams and reservoirs
The following is a list of reservoirs and dams, arranged by continent and country.
Africa
Algeria
# Djorf Torba Dam
# Keddara Dam
# Koudiat Acerdoune Dam
# Meraldene Dam
# boughrara Dam
# Beni Bahdel Dam
# Mafrouch Dam
# Si ...
References
External links
U.S. Bureau of Reclamation- Arrowrock Dam
- major storage reservoirs in the Boise & Payette River basins - current levels & flows
*
Historic American Engineering Record (HAER) documentation, filed under Boise River, Twin Springs, Boise County, ID:
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{{DEFAULTSORT:Arrowrock
Dams in Idaho
Reservoirs in Idaho
Hydroelectric power plants in Idaho
Buildings and structures in Boise County, Idaho
Buildings and structures in Elmore County, Idaho
Historic American Engineering Record in Idaho
Lakes of Boise County, Idaho
Lakes of Elmore County, Idaho
United States Bureau of Reclamation dams
Dams completed in 1915
Energy infrastructure completed in 1912
Dams on the Boise River
Arch dams
Boise Project
1915 establishments in Idaho
Historic Civil Engineering Landmarks