Prelude to the Dam’s Construction

Though ranchers, the Henry Schodde family utilized water wheels to divert Snake River water onto nearly 200 acres on the north side of Snake River, in what would become the Emerson area. Their success got the attention of the U.S. Geological Survey, who surveyed the area in 1889-1890
In 1902, Congress established the Newlands Act, later known as the Reclamation Act, forming a Reclamation Service to construct large projects- it soon became the Bureau of Reclamation.
Blessed by a natural falls, “Little Rapids,” had long served as an Indian camp; then later had been traversed by emigrants moving westward on the Oregon Trail
As early as 1879, ’80 or ‘81 talk began of taking water from a point called “Little Rapids” in the Snake River, near the mouth of Goose Creek. Frank Riblett borrowed $200 to buy a Gurley Survey transit, conducting a survey along the Snake, including :Little Rapids” and a site known as “the Cedars;” surveys showed both sites had promise; construction of Milner Dam was soon begun at “the Cedars;” since “Little Rapids,” or “Minidoka Rapids” was an equally ideal dam site; the Minidoka Project was later authorized as a result of this survey. Under the Carey Act, Ira B. Perrine, Stanley Milner, Frank Buhl and Peter Kimberly, formed the Twin Falls Land & Water Company; filing for rights to build Milner Dam; completed in1905, the dam supplied water to the newly-formed town of Twin Falls along with 270,000 acres of farmland
The success of the Twin Falls Southside project created a boom in developing Western irrigation; within ten years several more Idaho-based Carey Act projects were begun, including the Twin Falls-Oakley project that built Oakley’s Goose Creek Reservoir
State Engineer Douglas W. Ross proposed three Carey Act Idaho-based projects: Boise-Payette, Minidoka & Dubois; after his other projects met opposition, he focused his attention on Minidoka
After the Oregon Short Line Railroad laid tracks across the high desert and the town of Minidioka was established in the 1880s, a few farmers and ranchers started to work the nearby land; some accounts told of the government trying to discourage settlers from coming to the area too soon, since water may not be available for years; but as soon as word of the project got out, settlers rushed to the area to stake their claims; many lived in shacks, using barrels to collect water and burning sagebrush to stay warm

Construction Timeline

• 1894- Passage of the Carey Act by Congress, encouraged the reclamation of the high desert via irrigation
• 1895- Idaho accepted the Carey Act and Ira B. Perrine and a group of investors began work on Milner Dam on the Twin Falls South Side Project; Milner Dam was still under construction when the Minidoka Dam project was announced
• June 17,1902- The Reclamation Act was passed by the U.S. Congress and signed into law by President Thodore Roosevelt; the law specified 1)  all proceeds received by sale of public land in the West would be directed into a Reclamation Fund; 2) Settlers using these irrigation systems would pay back the Reclamation Fund over the long haul
• 1903- Construction of the dam was authorized, the Reclamation Service set aside $2.6 million dollars for the Minidoka Project
• July 2, 1904- bids were opened for the Minidoka Irrigation Project
• Dec. 1904, Work began upon completion of the assembling of a part of the plant 
• June 26- Sept. 13, 1906- Construction of the spillway, containing about 4.000 cubic yards of concrete; the concrete was mixed in a Ransome mixer, mounted on a truck, which moved forward as the work progressed
• October, 1906- Controlling gates in the diversion channel were lowered, and the water level in the reservoir raised to a depth of 10’ above the north canal bed; shortly thereafter, when a slight leak developed around the headgates, the water was lowered to permit driving a row of sheet piles on the north side of the forebay and the north cut-off was extended 40’; a truck dumped earth and gravel along the upstream side of the rock fill; much of it washed into the crevices and rocks, eventually stopping the water leakage
• Oct. 1906- Project was completed at a profit.
• Feb. 1907- With no further sign of seepage; this work was complete
• March, 1908- When the contract was reviewed, it was verified that funding for the project would be stopped if the canal system was not completed by June 23 of that year; since the network of canals was far from completed, a heroic effort was made to complete the required ninety miles of canals in ninety days, project workers and many local farmers were recruited in this seemingly impossible task
• June 23, 1908- Secretary of the Interior, James Buchanon arrived at 9:00 am to assess the project; the five-year deadline expired, with no further funding if specified construction was not complete; however, despite Garfield’s stated disdain for further funding the project, after a tour of the area, he declared the project was complete and additional funding would be made available
• 1910- Irrigation water was delivered to Cassia County farmers through the canal system
• Various improvements have been on-going, with a major renovation in the 1990s replacing the original generators
• Oct. 29, 1974- The power plant was added to the National Register of Historic Places 

Contract Details

• The original low bidder on the project was Mr. N.J. Blagen, but the contract was never executed
• Bates and Rogers Company was awarded the contract in 1904 after a two-month delay, when an executed agreement from the original low bidder could not be obtained
• In September 1904, the contractor began shipping equipment and supplies for the project to the town of Minidoka on the Oregon Short Line, then hauled six miles to the construction site by teams
• Several time extensions were required beyond those specified in the terms of the contract due to the initial delay at the beginning and weather-related slowdowns during the winter of 1905-06
• Total value of the contract- about $444.000
• Originally planned as a diversion dam, with a storage dam to be built at Jackson Lake in Wyoming, Minidoka Dam was later raised to provide storage when it became apparent that the Jackson Lake’s water was not sufficient

Power Plant & Pump Station

• The power plant at Minidoka Dam was the first power plant in the Pacific Northwest to provide hydroelectricity; as a result of its completion in 1908, local electrical co-ops were formed, supplying electricity to the region, long before electricity was available in most of the U.S.
• Minidoka Dam had the nation’s first hydroelectric generator, providing power to lift the water to the project’s higher lands south in Cassia County; one of the first reclamation projects in the nation, and the first in Idaho, in addition to being the Pacific Northwest’s first federal hydroelectric project  
• Construction of the power station was delayed because of the Panic of 1907
• The power plant included five generators, weighing 10,500 pounds, hauled from Minidoka by horse-drawn wagons
• The plant contained a 60 horsepower and an 80 horsepower boiler and a generating outfit for lighting the camp, along with various other hoisting engines and pumps.
• A variety of other hoisting engines and portable boilers were available for points not easily reached by the air pumps
• A 1924 edition of the Burley Bulletin stated, “The giant machinery installed in the powerhouse…shines like the deck of a new battleship…fairly glistening from constant burnishing, as they drone and hum at their giant task with a subdued sound that is an expression of inconceivable power.” 
• Water flows to the pump station north and east of Declo, where irrigation water is pumped into the 1st-, 2nd- and 3rd- lift canals, delivered to the higher land through a system of gravity-fed lateral canals throughout much of Cassia County
• The power plant was added to the National Register of Historic Places on Oct. 29, 1974, listed under reference #74000746

Manpower & Management

• Mr. D.G. Martin, Engineer, was temporarily in charge, assisted by L.L. Gay, Assistant Engineer, Engineering Aides R.M. Connor and W.C. Wilson
• On January 10, 1904. Mr. F.C. Horn, Constructing Engineer, superseded Mr. Martin, who was assigned to other contract work on the project
• Much of the labor was performed by recent immigrants, including Greeks, Italians, Austrians, Irish and Spaniards, after it was found that this working class was more efficient and reliable than local settlers; Greeks, Italians and Spaniards were held in highest regard.  
• Wages for common labor began at $.20/hour, and increased to $.22 ⅓ and later to $..25. Skilled labor wages are listed below: 
• Foremen were paid $90- $100/month; engineers $3.00- $3.50/day; firemen $2.25- $2.75/day, drillers $2.00- $3.00/day and carpenters $3.00- $4.00/day

Dam Construction

• Original plans anticipated the excavation of a large forebay canal, however after a revision of the designs placed the powerhouse in the dam itself, the forebay canal was eliminated; a smaller canal 2,000’  in length, was constructed in the forebay canal’s original location
• Excavation of the diversion channel and the north canal were begun simultaneously with the construction of the earth and rock fill
• The upper rock stratum excavated from the diversion channel was underlain by 12’ of sand 5’ to 20’ from the surface, and after caving in repeatedly, it was supported with a concrete lining, somewhat modifying the controlling’s and headworks’ designs
• The river’s high water level season, usually beginning during early May was delayed by cold weather in May and June, enabling the contractor to work above the rising water, but work continued by night and day to prevent overtopping
• When high water was reached, the rock fill had been raised to within 5’ of the dam’s crest, with gravel fill 20’ lower
• With all five flood gates wide open and water running nearly to the top of the penstock openings above them, the river rose until it reached an elevation of 4,237, or 3 feet below the spillway’s crest 
• Maximum discharge occurred on June 20, 1906, after which the water level fell with no further difficulty
• The deep channel of the river, near the north end of the site, the diversion channel and the controlling works were located in a rock ledge north of the stream’s deep position; 75’ wide at the top, 15’ deep at the base, sloping to 30’ deep thereafter
• After constructing the north end of the rock fill, it was extended across the stream until a gap of only 50’ was left for the river’s passage
• As soon as the diversion channel was excavated and the regulating gates installed, the river was diverted through them and the gap closed in April 1906
• Rocks varying in size from small stones to pieces weighing two tons or more were loaded into skips at the excavation site and dropped by cableways into place to insure packing
• The core wall was then completed; clay and gravel backfill were deposited from the timber trestle, which extended across the river to the borrow pits
• The earth and rock formed a cofferdam; after water was removed, a section of the concrete core wall was built; construction was made more difficult and delayed by storms and hindered by having to work during the river’s peak seasonal flow
• Material from the diversion channel was deposited in the deep section, with an earth embankment 12’  above the river surface, dumped by a wooden trestle on tracks
• Excavation for the long spillway was carried to solid rock
• The spillway was built in sections of 40’ with keys at the ends for bonding

Equipment Utilized in Construction

• Two cableways with a span of 1150’  were erected parallel to the axis of the dam; each cableway was provided with two movable towers, 80’ high, mounted on tracks, allowing a lateral motion of 150’ at right angles to the dam; power for each head tower was furnished by a 65 horsepower triple drum hoisting engine with an 80 horsepower boiler
• Air drills, supplied from a compressor located in the central plant were used to drill blast holes; the same compressor furnished air for the derrick hoisting engines and pumps
• Four stiff-leg derricks of 6-ton capacity with 48’ booms were provided, along with two guy derricks and a shears
• An orange peel dredge with a 50’ boom and a 1 cubic yard bucket were mounted on trucks for earth excavation; materials were hauled from the borrow pits to the dam in 16 automatic dump cars of 3 cubic yards capacity.
• Heavy trucks were used to haul steel slips
• Two gasoline-driven concrete mixers had 10 cubic yards per hour capacity
• 34 draft horses were utilized for teaming and hauling
• Numerous small articles of equipment and tools were also utilized

Scope of the Minidoka Dam Project

• When completed, the zoned earth-filled Minidoka Dam stood 66’ high, spanning 4,475’
• Water from Minidoka Dam irrigated nearly a million acres of South Central Idaho farmland
• The canal system north of the dam is gravity-fed; however most of the area south of the dam in Cassia County flows to the pump station north and east of Declo, where it is pumped into three lift canals, christened the 1st- Lift Canal, the 2nd- Lift Canal and the 3rd- Lift Canal; the Jackson area of Cassia County is served by gravity-fed canals, with no pumping required
• The controlling works rise 70’ above the tailrace of the powerhouse, with the north side canal headworks and connecting wall below contain 8,200 cubic years of concrete, mixed 1 to 7 in a Smith mixer, mounted on a tower mounted in the diversion channel
• Five 8’ x 12’ sluce gates, weighing 13 tons each, were skidded down the side of the channel and delivered into place on rollers

90 miles in 90 days Highlights from a Kathleen Hedberg Interview with Pop Baker

• If not completed by June 23, 1908, funding would be pulled
• Since there was no money, the Water Users Association printed $276,000 in script, not backed by anything- its only value was only what people were willing to give it.
• “If a man would not work for $10 a day, the directors offered $20. It wasn’t easy getting men even at that figure, “said Pop Baker. “Many thought the script was of no value anyway.”
• BishopThomas Taylor agreed to give $50 worth of groceries for $100 in script; since his safe wasn’t large enough to hold it, he kept the script in tomato cans on the shelf with the groceries. 
• The Reclamation Department, under President Theodore Roosevelt was notified the project would be completed before the 90 days was up
• Secretary of the Interior James Garfield was sent to Burley to verify that the South Side Minidoka Project was actually in operation 
• “When the secretary arrived, we had the 1st-, 2nd-, and 3rd- lift canals full of water, “ Pop Baker said, “I will admit that there were places in the third lift that were not more than two-feet deep and the checks to hold the water were sacks of earth, but the morning of Garfield’s arrival every man who had an acre or two or 80 close to the ditch was out irrigating.”
• Pop Baker and other members of the Water Users Board had ridden through the project the previous night to let the settlers know of the coming inspection.
• Secretary Garfield arrived at 9 a.m. and was taken over the project rapidly by Engineer Camp, who pointed out the homesteaders irrigating
• Time and time again, the secretary expressed his dismay that the project was completed
• Garfield never asked where the water came from and we never vocalized that detail,“ said Pop Baker, “As a matter of fact. the south side gravity canal had been completed to the first lift and we had installed a gasoline auger engine and pump to lift the water into the 1st- lift canal and used Marsh Creek water for the 2nd- and 3rd- lift canals
• After touring the project, Garfield met with the Water Users Board directors to approve the project, telling the directors that the government would furnish the additional money for its completion
• Idaho Senator WIlliam E. Borah got the government to redeem the script issued by the Water Board, finally agreeing to accept it for the payment of water charges. 

Sources:  Construction of the Dam;  The Minidoka Irrigation Project by Julie Fanseslow, published in undated Project Mutual Phonebook; South Idaho Press, June 28, 1994 Historian’s Corner, by Kathleen Hedberg, most of her material came from an interview with Pop Baker, Cassia County, The Foundation Years by Kathleen Hedberg; materials provided by Rick Parker