- Reclamation
- Projects & Facilities
- Projects
- Minidoka Project
Minidoka Project
State: Idaho
Region: Pacific Northwest
Related Documents
Minidoka Project History (89 KB)
Minidoka Project Brochure (727 KB)
Related Facilities
Related Links
American Falls Reservoir
Grand Teton National Park
Grassy Lake
Island Park Reservoir
Jackson Lake
Lake Walcott
Milner Historic/Recreation Area
Minidoka National Wildlife Refuge
Palisades Reservoir
Yellowstone National Park
Streamflows: Snake River at Milner, Idaho (USGS)
American Falls
Blackfoot
Idaho Falls
Lake Walcott
Little Wood
Lower Henrys
Portneuf
Upper Henrys
Upper Snake - Rock
Major Storage Reservoirs in the Upper Snake River Basin
Precipitation
Snake River near Heise, Idaho (USGS)
Snake River near Blackfoot, Idaho (USGS)
Henrys Fork near Island Park, Idaho (USGS)
Snake River Gaging Station at Milner, ID (USGS)
Spring and Summer (NRCS)
Mountain Snowpack Maps for Columbia River Basin
Columbia River Snowpack Summary
Palmer Drought Index Map
Explanation of Palmer Drought Severity Index (Text)
Weather Conditions (NOAA)
Falls River above Yellowstone Canal, near Squirrel, Idaho (USGS)
Big Wood
Teton
General
Minidoka Project lands extend discontinuously from the town of Ashton, in eastern Idaho along the Snake River, about 300 miles downstream to the town of Bliss in south-central Idaho. The project furnishes irrigation water from five reservoirs that have a combined active storage capacity of more than 3 million acre-feet. The project works consist of Minidoka Dam and Powerplant and Lake Walcott, Jackson Lake Dam and Jackson Lake, American Falls Dam and Reservoir, Island Park Dam and Reservoir, Grassy Lake Dam and Grassy Lake, two diversion dams, canals, laterals, drains, and some 177 water supply wells.
History
In 1904, the lower Minidoka Project area around the present cities of Burley and Rupert was a nearly uninhabited sagebrush desert with only a few scattered ranches. After construction of the initial phases of the project brought water to the land, giving opportunity for expansion, it became a prosperous, highly developed farm area. By 1919, 2,208 farms were in operation, there were 6 towns, and the total population was about 17,000.
Construction
There are over a million irrigated acres in the arid Snake River valley of southern Idaho. Much of the famed Idaho potato crop is grown in this valley, and sugar beets, dry beans, sweet corn, field grains, alfalfa hay, and irrigated pasture diversify the land use. Cattle raising and dairying are important industries. The five project reservoirs provide about 36,000 acres of land and about 102,000 acres of water surface, with 319 miles of shoreline for recreational use. American Falls Reservoir is the largest with a total land and water area of over 68,000 acres. The Bureau of Reclamation administers recreation at the reservoir and has leased out three areas for recreation development. The reservoir offers fishing for both salmonoid and spiny ray species, and millions of waterfowl use the area annually. Jackson Lake is located within Grand Teton National Park and recreation is administered by the National Park Service. With the Teton Mountains as a background, excellent facilities, and Yellowstone National Park only a few miles away, the reservoir attracts many vacationers. The Minidoka National Wildlife Refuge, consisting of a major portion of the Lake Walcott area, is administered by the Fish and Wildlife Service. Part of the area open to public hunting, and fishing is provided in the reservoir. Several million waterfowl use the area each year. Both Island Park Reservoir and Grassy Lake are administered by the Forest Service. Many recreation facilities have been constructed at Island Park Reservoir. There is good fishing for rainbow trout and coho and kokanee salmon at the reservoir, and it is used by large numbers of waterfowl during their migrations. Snow-mobiling is a very popular activity in this area. Grassy Lake is a small reservoir located just outside the southern boundary of Yellowstone National Park. Visitation is light but there is some trout fishing. Since 1993, in response to provisions in Biological Opinions for listed anadromous fish, the Bureau of Reclamation has provided 427,000 acre-feet of water for flow augmentation in the lower Snake and Columbia Rivers. Water has been provided from Bureau of Reclamation uncontracted reservoir space and natural flow rights the Bureau of Reclamation has acquired from willing sellers, and rental of water from Idaho rental pools (District 1--Upper Snake River, District 63--Boise River, and District 65--Payette River. River recreation uses are an extremely important component of the recreation mix, providing opportunities for whitewater rafting and kayaking, floating, canoeing, fishing, picnicking, and other uses. Various reaches of river from Jackson Lake to below American Falls are regionally and nationally recognized for exceptional whitewater and blue ribbon trout fishing, and other water borne recreation activities. These activities are incidental to authorized project purposes. For specific information about any of these recreation sites, click on the name below. http://www.recreation.gov/detail.cfm?ID=105 http://www.recreation.gov/detail.cfm?ID=961 http://www.recreation.gov/detail.cfm?ID=1234 http://www.recreation.gov/detail.cfm?ID=111 http://www.recreation.gov/detail.cfm?ID=1240 http://www.recreation.gov/detail.cfm?ID=115 http://www.recreation.gov/detail.cfm?ID=1713 http://www.recreation.gov/detail.cfm?ID=1516 http://www.recreation.gov/detail.cfm?ID=1250 http://www.recreation.gov/detail.cfm?ID=963 The reservoirs of the Minidoka Project were designed originally to provide for distribution of spring runoff through the irrigation season, rather than to provide for carryover storage for years of low streamflows. The addition of Palisades Reservoir provides not only holdover storage, but also an increased measure of flood control over the river. Sufficient vacant space is maintained in Jackson Lake and Palisades Reservoir on a forecast basis to prevent flows on the Snake River near Heise from exceeding 20,000 cubic feet per second. The flood control operation is carried out under formal agreement with the Corps of Engineers. The Minidoka Powerplant serves large irrigation pumping requirements on and near the Minidoka Project in southern Idaho. Power not needed for Bureau of Reclamation project purposes is marketed in the Federal Southern Idaho Power System administered by the Bonneville Power Administration. According to the Idaho Historical Society, Minidoka is a Dakota word meaning `a fountain or spring of water.`[i] The word is appropriate for the Project. One of the oldest Reclamation projects, the Minidoka Project contains seven dams, 1,600 miles of canals and nearly 4,000 miles of laterals. Part of the Minidoka Project lies in an arid and forbidding expanse of volcanic soil and sagebrush. The reservoirs of the Project lie in the forested hills and mountains of eastern Idaho and northwestern Wyoming. Even today, the area remains lightly populated. Only the hardy dare brave temperatures that consistently drop to twenty degrees below zero during the winter or skyrocket above 100 in the summer. The extreme dryness of the area made it a perfect candidate for irrigation by the Bureau of Reclamation.[ii] The Minidoka Project operates in Reclamation`s Pacific Northwest Region. The entire Project stretches across most of southeastern Idaho and into northwestern Wyoming. Minidoka irrigates over one million acres in Teton, Fremont, Jefferson, Bonneville, Bingham, Cassia, Minidoka, Power, Jerome, Lincoln, Bannock, Gooding, and Twin Falls Counties of Idaho to the tune of over one million acres. Teton County, Wyoming, contains Jackson Lake and Grassy Lake Dams and Reservoirs, and Cascade Creek Diversion Dam. Fremont County, Idaho has Island Park Dam and Reservoir, and Cross Cut Diversion Dam and Cross Cut Canal. American Falls Dam is located in Power County, Idaho while the reservoir lies in both Power and Bingham Counties. Minidoka Dam and Lake Walcott, as well as the North and South Side Divisions are in Cassia County. Milner-Gooding Canal irrigates Lincoln, Jerome, Twin Falls, and Gooding Counties.[iii] Two Native American groups inhabited southeastern Idaho prior to immigration by Europeans in the nineteenth century. The Bannocks, a Northern Paiute speaking people, migrated from Oregon to the area of the Snake River plains. They differed from other Northern Paiutes by their acquisition of horses and organized buffalo hunts. The Bannocks co-existed peacefully in Idaho with Northern Shoshones. Native grasses supported buffalo in the upper Snake River plains until about 1840. Fish also contributed largely to both Native American groups` subsistence.[iv] In the 1850s, Mormon settlers established the Fort Lemhi mission in Idaho. By the end of the decade, escalating conflicts with the Bannocks turned violent. The 1857-58, clashes coincided with a U.S. military force approaching Utah, convincing Brigham Young, Utah`s territorial Governor and President of the L.D.S. Church, to recall the settlers to Utah. Mormon settlers returned to southern Idaho in the 1860s, and gold miners entered the Sawtooth Mountains in force.[v] The Bannocks and the various groups of the Shoshones found themselves placed on reservations starting in the late 1860s. The Federal government originally set up the Fort Hall Reservation in 1867, for the Boise and Bruneau Shoshone, and introduced the Bannock and other Shoshones to the reservation after the Fort Bridger Treaty of 1868. The government established the Lemhi Reservation in 1875, for the Lemhi and the Sheepeater Shoshone, but shut it down in 1907, and then also moved its residents to Fort Hall. The swelling of the white population increased friction between the newcomers and the native inhabitants, and the reservation system did not prevent conflicts. One such conflict, the Bannock War of 1878, started in Idaho, but moved west and ended with the Northern Paiute in Oregon. Disputes between white miners and Sheepeater Shoshones erupted in the Sheepeater War of 1878-79. Both conflicts ended the same as other confrontations between Native Americans and whites, in favor of the latter.[vi] Irrigation began in Idaho in the 1840s, when Reverend Henry H. Spalding, a missionary at Lapwai, dug a ditch from the Clearwater River to supply his dying garden with water. The Mormon settlers brought more irrigation experience with them to the state, and the U.S. Geological Survey first conducted investigations of irrigation possibilities of Idaho in 1889-90. The Idaho State Engineer ordered further surveys five years later. Private organizations toyed with irrigation possibilities after 1887, but made no definitive investigations of the idea.[vii] Meanwhile, in Minidoka County, water wheels were used to irrigate 200 acres of the `Old Jimmy Howell Place.`[viii] In 1900, Ira B. Perrine combined Idaho, Illinois, and Pennsylvania interests to bring water to the Twin Falls area. Perrine convinced Stanley Milner, a Salt Lake City businessman, to invest $30,000 in a survey for the irrigation project. In 1903, the state of Idaho contracted with Twin Falls Land and Water Company (Perrine`s group), and the company built Milner Dam, named for Stanley Milner. When Congress passed the Reclamation Act in 1902, D.W. Ross, Reclamation`s District Engineer in Idaho, initiated the work of Reclamation in Idaho. Surveys began on the headwaters of the Snake River in order to determine water storage potential.[ix] On November 17, 1902, Secretary of the Interior Ethan A. Hitchcock withdrew the irrigable land of the Minidoka Project from public entry. Survey parties started initial work looking toward locating canals in the project area on both sides of the Snake River. Surveys indicated the North Side could be irrigated by gravity with canals. The South Side of the Project needed pumping plants to get river water to the area. In December 1903, Ross reported to Reclamation, recommending immediate construction of the Project. A consulting board reviewed a report of estimated costs the next spring. In March, the board reported favorably to the Secretary of the Interior. Ethan A. Hitchcock gave the Minidoka Project his approval on April 23, 1904, and allotted $2.6 million to the Project.[x] Initial construction of the Minidoka Project began under D.W. Ross, the Project Engineer. Reclamation wasted no time in commencing work on the Project. On September 30, 1904, the Utah Portland Cement Company of Salt Lake City received a contract to supply 14,000 barrels of cement for construction of the Minidoka Dam. N.J. Blagan first received the contract for the construction of the dam, but failed to begin work. Reclamation then awarded the contract to Bates and Rogers Company, but two months of the working season had already been lost. Bates and Rogers started shipping equipment and making construction preparations in September 1904.[xi] Work on the dam began with the excavation of a diversion channel. Afterwards Bates and Rogers erected a section of the eight foot high corewall. Due to the late start workers encountered a high stage of the Snake River which caused some problems in removing the water from the corewall area. Workers constructed the north side rockfill and the regulating gates of the dam and diverted the water through them. Work then commenced on the remaining fifty feet of the structure. First, workers completed the corewall, and then the remaining rock fill. Bates and Rogers excavated the spillway concurrently with construction of the dam. The contractor finished the excavation and began placing concrete on June 26, 1906. Work crews finished concrete work on the spillway the following October, completing the work on the dam.[xii] Most of the laborers on Minidoka Dam were from outside the United States because their work proved more satisfactory than the local hires. Greeks, Italians, Austrians, Irish, and Spanish workers participated in construction of the dam. The Project History of 1912 especially lauded the work of the Greeks, Italians, and Spanish.[xiii] The Minidoka Project was one of the first Reclamation projects to incorporate hydroelectric power. The Minidoka Powerplant at Minidoka Dam became the first hydroelectric powerplant on the Project. After much debate, engineers J.H. Quinton, O.H. Ensign, and A.J. Wiley chose a site about 2,000 feet below the north end of the dam and 900 feet back from the river channel for the powerplant. They planned to divert water to the powerplant through a forebay canal and release it back to the river via a tailrace.[xiv] In August 1904, two engineers, Storrs and Ross, proposed a significant change in the plans. Original plans called for a diversion channel near the north end of the rockfill of Minidoka Dam to control the river during construction of the fill. Afterwards, construction workers would build a concrete dam, containing five regulating gates, across the channel. Storrs and Ross proposal widened the concrete dam, and built it as a foundation and upper wall for the powerplant. The concrete portion contained ten penstocks, each with a ten foot diameter. The modified plans necessitated the eventual excavation of a tailrace, but eliminated excavation of a forebay for the powerplant.[xv] The Minidoka Powerplant entered operation in 1909. The Minidoka Powerplant was the third power generation structure built by Reclamation. Construction of the plant finished in 1909. The powerplant supplied electricity for irrigation and drainage pumping. Reclamation sold the excess power commercially.[xvi] The revised powerplant construction eliminated a portion of the construction contracted by Bates and Rogers. To make up for the lost work, Reclamation added the excavation of 2,000 feet of the main North Side Canal to the contract. Bates and Rogers completed the new work by October 1906, as well. During the month Reclamation closed the controlling gates of the diversion channel and began filling Lake Walcott, the reservoir behind Minidoka Dam. Reclamation named the lake for Charles D. Walcott, Director of the U.S. Geological Survey.[xvii] Located six miles south of Minidoka, Idaho, Minidoka Dam was eighty-six feet high, twenty-five feet wide at the crest, with a maximum base width of 418 feet. The dam`s crest was 4,475 feet, and the dam contains 257,300 cubic yards of material. Lake Walcott has a total capacity of 210,000 acre-feet with an active capacity of 95,200 acre-feet.[xviii] In the spring of 1905, Reclamation opened the contract bidding for the Project`s canal systems, and awarded contracts that July. Excavation of the canal systems commenced immediately upon approval of the contracts. The contractors in turn sublet much of the work to local workers. Severe winter weather hindered progress on initial grading leading to a thirty day contract extension by Reclamation. Reclamation furnished concrete, steel gates, and controlling machinery to all the contractors, and took over the construction of five structures in the canals and built them of wood to speed progress. In spite of this effort the contractors did not complete their work until July 1907.[xix] Excavation by contract began on the first and second lift canals in March 1908. Both contractors finished by the end of June. In order to supply water to the South Side in 1909, Reclamation decided at least one pumping unit needed to start operation. Construction of the pumping plant commenced in the fall of 1908, and continued through the winter. Farmers on the South Side received their first irrigation water the following May. The North Side Canal extended a distance of eight miles in a southwesterly direction from Minidoka Dam. The South Side Canal travelled from Minidoka Dam to the first lift pumping plant.[xx] It became apparent to Reclamation that continuing development of irrigation in the Upper Snake River Valley required more water storage for future additions to the Project. Reclamation deemed Jackson Lake, in Teton County, Wyoming, the only site capable of storing the required 216,000 acre-feet of water. When Reclamation officially adopted the site, it made plans for a temporary timber dam to raise the surface of the lake ten feet. This would increase Jackson Lake`s capacity to 350,000 acre-feet.[xxi] Construction of the temporary dam began by force account in July 1906. Government forces built a timber crib for the center section, floated it to the desired area, and sank it by filling it with rocks. The short work season, about three months, limited the amount of work accomplished in any one year. Reclamation finished the dam in June 1908. On July 5, 1910, the crib section of Jackson Lake Dam gave way because the wood in the crib rotted. This necessitated the construction of a permanent dam, which received approval in 1910.[xxii] Construction of the new Jackson Lake Dam involved enlarging Jackson Lake by raising it seventeen feet. Initially Reclamation awarded the construction contract to Kuhn Irrigation and Canal Company. Later Twin Falls Canal Company became involved in the contract. Kuhn experienced financial difficulties resulting in construction delays in 1913, the initial year of work. The contractors only completed preliminary work during the year. Reclamation instructed F.A. Banks, the Reclamation engineer at the dam, to continue work on April 4, 1914.[xxiii] Reclamation wanted to raise the concrete portion in 1914, to a level where construction could resume in spring 1915, and also would allow enough stored water for the North Side Division`s use. Work on the foundation of the south one-third of the dam, including the fish ladder, logway, and the south abutment. Foundation work and concrete placement of the rest of the dam followed shortly. The only concern about reaching the year`s goals arose from finding the bedrock under the west wing of the north abutment was thirty to thirty-five feet below the estimated necessary water level, but the extra work caused no problems.[xxiv] The new dike of Jackson Lake Dam was built on the site of the temporary structure. Stripping of the dike`s foundation began in 1914, and finished June 11, 1915. The old dike formed the upstream face of the new dike. Meanwhile work on concrete placement continued in 1915, most of it finishing on June 16, except for some sections of the corewalls. Concreting of these finished on November 18, 1915. Workers completed work on the dam in 1916. Water first flowed over the spillway July 2, 1916, and workers placed the last dirt and riprap on the dike August 31.[xxv] The new Jackson Lake Dam is a concrete gravity dam with embankment wings. The dam is sixty five and a half feet high. It has a top width of twenty feet and a maximum base width of seventy-two feet. The dam is 4,920 feet long. Jackson Lake, a conglomeration of several small lakes combined because of the increased water elevation, held 847,000 acre-feet after post-construction improvements.[xxvi] After construction of Jackson Lake Dam, Reclamation held off building any new structures during the 1910s. The 1920s brought construction of American Falls Dam across the Snake River as the next addition to the Minidoka Project. American Falls Dam brought with it more than engineering challenges. It also brought a new challenge for Reclamation, relocating most of the city of American Falls, Idaho. Upon completion American Falls Reservoir would inundate sections of Aberdeen, Springfield, and Sterling, Idaho, in addition to nearly three-quarters of American Falls. Reclamation offered to buy land on the prospective reservoir, and the Project History of 1920 claimed most owners accepted. Reclamation moved into court for condemnation proceedings against owners who refused to sell. One condemnation case went to the U.S. Supreme Court which upheld the government`s action.[xxvii] Reclamation bought the new site for American Falls to keep property prices down for those residents of the old site forced to move. In 1923, Reclamation hired Russell V. Black, the city planner of Highstown, New Jersey, to plan the new city of American Falls. Reclamation also hired Sylvester Q. Cannon, the city engineer of Salt Lake City, to map out improvements in the city. Reclamation relocated many of the large structures from the old town site to the new town. Most building owners moved the buildings at their own expense. The three story Grand Hotel and several grain elevators were the largest buildings moved. Moving buildings often took several days or weeks, and the work continued well into 1926.[xxviii] Utah Construction Company received the contract for construction of American Falls Dam in 1925. Originally the dam was to impound 1,045,000 acre-feet. Later Reclamation planned a larger structure in order to retain more water. During 1925, work on the dam was limited to the east half of the dam while deciding whether or not to increase the dam`s size. Utah Construction placed twenty five by five foot high pressure outlet gates, the fifteen foot penstocks, for the Idaho Power Company, and the concrete in this section. Reclamation told Utah Construction in February 1926, to construct the larger dam. Early 1926, saw Utah Construction lay the foundation on the west section of the dam. The company installed the four 15 foot penstocks for the government powerplant, and started the corewall in the right embankment.[xxix] Utah Construction concentrated on the spillway and left abutment in the spring in order to allow the dam to capture as much storage water as possible for the irrigation season. Workers completed installation of the fifteen radial gates in October. Utah Construction finished all the concrete placement except for one section by September 1926, and in October removed the last cofferdams and the reservoir filled for the first time. Utah Construction completed the final work on American Falls Dam in April 1927. American Falls Dam was a concrete gravity structure with embankment wings. The dam was 103.5 feet high with a crest length of 5,277 feet. The crest width of the dam was 42.5 feet. American Falls Dam contained a volume of 1,374,300 cubic yards of material.[xxx] American Falls Reservoir flooded some of the lands of the Fort Hall Reservation. Reclamation negotiated with the Indian Service, later the Bureau of Indian Affairs, to appraise the reservation lands for purchase. In addition to flooding the lands, some people feared the reservoir would engulf Fort Hall itself. Fort Hall escaped flooding, but in 1993, Reclamation preservation officers debated the erosion threat to the fort, and it was listed as an endangered site.[xxxi] Milner-Gooding Canal began life as the Gravity Extension Division. Reclamation intended to connect Milner Lake, behind Milner Dam, with the various privately built canals of the area. This would increase the irrigable area on the Minidoka Project. North Side Canal Company, South Side Canal Company, and Twin Falls Canal Company built Milner Dam privately, completing it in 1905.[xxxii] Derbon Construction, of Seattle, and Winston Brothers Company, of Minneapolis, contracted for one schedule each on Milner-Gooding Canal in July 1928. Derbon Construction encountered earth and cinder pockets and seams in the rock that resulted in breaking out more material during excavation than desirable in 1929. Reclamation responded by revising plans for lining the canal bottom with concrete and fill the seams in the rock sides with gunite. Derbon Construction fought through the difficulties and completed the contract on December 21, 1929.[xxxiii] Winston Brothers started construction on their contract before the end of the month, and before Reclamation notified both contractors in August to begin work. Winston Brothers stopped work during the winter of 1928-29, because of severe weather conditions. Excavation work resumed March 4, 1929. Winston Brothers encountered few problems outside of weather, and work continued smoothly. The company finished their contract on November 8, 1929.[xxxiv] Reclamation entered various contracts in the Milner-Gooding Division during 1929. John Phillips Company and Mittry Brothers Company for earthwork and structures on the Division. Phillips stopped work for the winter in December. Phillips also contracted to excavate a section of canal. Reclamation awarded several contracts for canal structures, bridges, and diversion works to connect the Milner-Gooding Canal with the existing Twin Falls Company Canal.[xxxv] In June, Derbon Construction started work on the diversion facilities for the canal at Milner Lake. They built a cofferdam in Milner Lake and a channel above the headworks structure to divert water away from construction. Work proceeded quickly, allowing Derbon to complete the headworks in mid-December. Following completion of the canal past Station 38+25, the company erected a steel bridge at this point. Derbon once again encountered seamed rock while excavating for the concrete abutments. The rock shattered easily forcing the company to extend the abutments deeper than originally planned.[xxxvi] Work on the Milner-Gooding Canal continued without serious hindrances. John Phillips Company`s excavation came across very porous material in one section. Workers excavated the section two feet below the grade and back filled it with dirt to prevent seepage. In another section Reclamation discovered excessive excavation could be avoided, and better water tight integrity established by changing the alignment of the canal between Stations 1686 and 1760. Derbon Construction, Winston Brothers, and John Phillips finished work on their contracts by the end of 1931.[xxxvii] Reclamation entered into the final contracts on the Milner-Gooding Canal in 1931. The main construction contract went to Haas, Doughty, and Jones for construction of the canal below the Big Wood River. Morrison-Knudsen Company, Inc., connected the canal to the Big and Little Wood Rivers. Work progressed until the winter of 1931-32. Heavy rain and snow fall in the spring of 1932, slowed Haas, Doughty, and Jones considerably. The company finished their contract May 10, 1932, just one day before the time limit. The end of the Haas contract completed the Milner-Gooding Canal. Milner-Gooding Canal extended from Milner Lake to the vicinity of Gooding, Idaho. The canal covered a distance of seventy miles with a capacity of 2,700 second-feet.[xxxviii] During the late 1930s, Reclamation built Island Park Dam, Grassy Lake Dam, Cascade Creek Diversion Dam, and Cross Cut Diversion Dam and Cascade Creek Feeder Canal and Cross Cut Canal as part of the Upper Snake River Project. Upon their completion Reclamation transferred the dams, the canals, and the Fremont-Madison Division to the Minidoka Project. The transfer in 1940, added nearly 150,000 acre-feet of stored water, several miles of canals, and 995 farms to the Project.[xxxix] Max J. Kuney received the contract for the construction of Island Park Dam in 1934. Kuney moved quickly on the construction beginning to clear the dam site and building the construction camp and access road before the end of the year. Work on the dam started in spring of 1935, when workers began excavating the spillway. Workers started the inlet and outlet tunnels in March. Three months later Kuney recommenced clearing the dam site after snow levels from the previous year had dropped enough to allow work to continue. Most of the early work concentrated on the diversion and outlet tunnels. Rock fill of the dam and dike embankment started in 1936.[xl] Rhyolite rock in the spillway frequently shattered, slowing excavation. Workers excavated and lined the spillway with concrete through most of 1937. Workers brought the dam to within 12 inches of the final crest height in 1937, but heavy snow forced construction to halt for the winter. The contractor started again on June 11, 1938. Grouting work on the foundation rock started June 22, and was completed August 15. Derbon Construction resumed placement of earthfill on the upstream section of the dam above the auxiliary cutoff wall on July 27. This allowed the placement of earthfill over the rest of the dam until October 1, when workers completed the structure. Island Park Dam is a zoned earthfill dam and dike ninety-one feet high. The top width is thirty-five feet with a maximum base width of 585 feet and a length of 9,450 feet. Island Park Dam contains 564,000 cubic yards of material. The dam impounds 127,600 acre-feet of water.[xli] Operations on the Cross Cut Diversion Dam and Canal began in August 1936. Otis Williams and Company and Brent Sturgill Company combined on the two projects. Otis Williams started the dam with Sturgill excavating the canal. Work on the diversion dam ran into problems when Reclamation discovered the foundation was composed of compacted gravel on top of finer gravel and sand. This required a change in dam design because Reclamation originally thought the dam would have a solid rock foundation. As a result workers laid an eight inch thick, fifty foot concrete apron extending upstream from the dam. An eight foot deep cutoff trench filled with impervious, compacted material and a five foot deep cutoff wall further reinforced the foundation integrity.[xlii] Because workers placed all the concrete on the Cross Cut Dam in cold or freezing weather they had to keep the cement mix heated. In the coldest weather crews heated the sand and gravel as well. Work on the dam eventually stopped for the winter and resumed in 1937, as soon as weather permitted. The contractors faced no more problems after the change in design, and they finished the dam by the end of the year. Clean up operations took place in the beginning of 1938. After completion, Cross Cut Diversion Dam was a seventeen feet high, concrete gravity, overflow, ogee weir. The total length of the dam is 457 feet with 7,400 cubic yards total volume.[xliii] Brent Sturgill Company started the work on Cross Cut Canal. Equipment breakdowns slowed progress on the canal by requiring time consuming repairs. The slowed progress forced the company to pour concrete for the canal structures in cold weather. As with the Cross Cut Dam, crews heated the mixture and structures after pouring. In 1937, Otis Williams Company took over excavation of the canal from Sturgill, subcontracting the work to A.L. Nelson. Nelson started work on the canal April 6. R.S. Humphrey assumed construction of canal structures from Sturgill`s subcontractor Walter Bell. Most work on the canal finished in the spring of 1938. Testing and repairs of the canal started in May. Workers completed the final cleanup work on the Cross Cut Canal at the end of June 1938. Cross Cut Canal extended 6.6 miles south from the Cross Cut Diversion Dam to the Teton River.[xliv] Bids for the construction of Grassy Lake Dam opened in August 1936, with S.J. Groves and Sons Company of Minneapolis placing the winning bid. Reclamation did not give notice to proceed with work until 1937. Government forces built the construction camp for the dam as early as weather permitted in advance of the contract workers` arrival. Groves subcontracted construction of Grassy Lake Dam to Lobnitz Brothers of Willmar, Minnesota, for earthwork, and Landreth Construction of Scotts Bluff, Nebraska, for concrete work.[xlv] The subcontractors completed approximately almost one-quarter of the dam during the 1937 work season, which as usual proved short because of inclement weather conditions. During 1937, workers completed: the headworks structure and rough excavation of the spillway in the left abutment of the dam; preparation of the dam foundation, including completing cutoff trenches, cutoff walls and footings, and a grouting curtain in the dam foundation. Concrete placement in the outlet conduit began in August and ceased for the year in October. Nevada Construction Company commenced clearing timber from the reservoir in June 1937.[xlvi] Work on the dam did not resume until June 1938, due to severe weather conditions. The contract required September 7, 1938, for the completion date. Reclamation extended the contract seventy-five days to November 21. By October 6, freezing weather forced still incomplete construction work to halt. Workers finished most of the structural work by the stop date, but completed only about half of the construction on the dam embankment. Rock and earthfill work on the dam continued in the 1939 work season. Workers put final touches on the dam, and Reclamation accepted the work on September 9, 1939. Grassy Lake Dam is zoned earthfill 118 feet high and thirty feet wide at the top. The maximum base width is 738 feet and with a crest length of 1,170 feet. The dam has a total volume of 539,000 cubic yards. Grassy Lake Dam retained 15,500 acre-feet of water.[xlvii] Reclamation realized the water from Grassy Creek would not provide enough storage behind Grassy Lake Dam. To make up the deficiency Reclamation decided to build a diversion dam and canal to supply water to Grassy Lake from Cascade Creek. Bennett and Taylor of Los Angeles received the contract for both in July of 1937. Bennett and Taylor`s work progressed rapidly from the start of construction on August 2. The contractor built a log crib structure with eight by eight foot compartments filled with rock. Each log in the crib had a minimum diameter of twelve inches. Bennett and Taylor constructed a reinforced concrete headworks structure to the canal. A log bridge across the canal provided the Forest Service with access to a large forested area for fire protection. Bennett and Taylor completed the contract October 16, 1937, more than a month before the date required by the contract. Cascade Creek Diversion Dam is a rockfilled timber crib weir. The dam is fourteen feet high, 217 feet long with a volume of 300 cubic yards. The Cascade Creek Feeder Canal stretches only 0.7 miles from Cascade Creek Diversion Dam to a natural channel which fed water to Grassy Lake Reservoir. Reclamation transferred all these structures from the Upper Snake River Project to the Minidoka Project in 1940.[xlviii] Reclamation began the final additions to the Minidoka Project in 1954. Vernon Brothers received the contract for the Unit A Canal and laterals in the newly forming North Side Pumping Division. Work started on the contract October 21. Work continued steadily with no major problems and finished March 30, 1956. Unit A Canal runs 4.4 miles from the Snake River to within eight miles of Burley. Reclamation awarded numerous contracts for Unit B of the Division. The plans for Unit B specified 190 wells built by contract to supply most of the water for the division. This endeavor took many years to complete as contractors seemed to continually add on to the Project in later years. The Unit B contract was finally completed in November 1963. Upon completion Unit B had 177 wells.[xlix] Construction activities on the project began in 1904 at Minidoka Dam which, with its associated diversions and canals, formed the nucleus of the present development. Headwaters storage began with the erection of the temporary Jackson Lake Dam in 1905. Later major developments were the enlargement of Jackson Lake in 1911 and 1916, the original construction of American Falls Dam in 1925-1927, construction of Grassy Lake and Island Park Dams in 1935-1939, and American Falls Replacement Dam in 1976-1978. The first power came from the Minidoka Powerplant in 1909; the last generator was installed in 1942. Construction on the last project land area to be developed, North Side Pumping Division, began in 1948 and was completed in 1959. The Palisades Reservoir, while not a part of the Minidoka Project, contributes greatly to the project`s success by storing excess flows for later release and by increasing the available power supply.
Plan
Natural flow of the Snake River and some of its tributaries, and water stored in the reservoirs at Jackson Lake, Grassy Lake, Island Park, American Falls, and Lake Walcott are delivered at numerous diversion points to the A & B, Falls, Fremont-Madison, Burley, and Minidoka Irrigation Districts, American Falls Reservoir District No. 2, and supplemental supply contractors. A full or supplemental irrigation water supply is furnished to about 1.1 million acres. Water from Palisades Reservoir in the Palisades Project is instrumental in helping meet the Minidoka Project water requirements. Originally power was developed on the project for pumping water to lands lying above the gravity canals and for pumping drainage water. Power was also furnished to several small communities in the area. Subsequently, Federal power has been provided for groundwater pumping projects. Minidoka Dam is a combined diversion, storage, and power structure located just south of Minidoka, Idaho. A key structure in the initial development of the project, the zoned earthfill dam is 86 feet high. The reservoir, Lake Walcott, has a total storage capacity of 210,200 acre-feet (active 95,200 acre-feet). Water is diverted at the dam into a canal on each side of the river. The original concrete powerplant, forming a section of the dam, was completed in 1909 and had five generating units. Unit 6 was added in 1927 and unit 7 in 1942 to provide a total capacity of 13,400 kilowatts. During 1989 - 1990, the spillway radial gates were replaced. The original gates were installed in 1913 and were in need of complete replacement. Units 1 through 5 in the Minidoka Powerplant have been retired and preserved as museum pieces in the powerplant. Unit 6 has been replaced and modern controls have been installed in Unit 7. In addition, a new powerhouse, the Allen Inman Powerplant, housing two units was constructed near the left abutment of the dam. With these changes, the nameplate generating capacity was increased from 13,000 kilowatts to about 28,000 kilowatts. These activities were completed in 1997. Water is diverted from the north side of Lake Walcott into the North Side Canal, a gravity canal and lateral system serving 72,000 acres of land called the Gravity Division, in the vicinity of Rupert, Idaho. The 8-mile main canal has an initial capacity of 1,700 cubic feet per second. Water is diverted on the south side of Lake Walcott near the right abutment of Minidoka Dam into the South Side Canal. The 13-mile canal serves a narrow strip of the Gravity Division before delivering the majority of its flow to a series of three large pumping plants. Each plant lifts the water about 30 feet, for a total lift of about 90 feet. The system, served by the pumps, is known as the South Side Pumping Division and serves 48,000 acres adjacent to Burley and Declo. The canal is 13 miles long and has an initial capacity of 1,325 cubic feet per second. Title to the South Side Canal, as well as all rights-of-way, pumping plants, canals, laterals, drains, transmission lines, and appurtenant facilities, are to be transferred to the Burley Irrigation District (the operating agency for the South Side Pumping Division) not later than January 27, 2000, pursuant to Congressional authorization. A temporary rockfilled crib dam was completed in 1907 by the Bureau of Reclamation at Jackson Lake to store 200,000 acre-feet for the Minidoka Project until the storage requirements could be determined. A portion of this dam failed in 1910, and in 1911 a concrete gravity structure with earth embankment wings was built at the site. The new dam increased storage capacity to 380,000 acre-feet. In 1916, further construction raised the dam 17 feet to a structural height of 65.5 feet, with a total storage capacity of 847,000 acre-feet (active 847,000 acre-feet). Safety concerns were identified at the dam in the mid-1970's, and from 1977 to 1989 the level of Jackson Lake was maintained at a lower than normal level because of concerns for possible dam failure during an earthquake. The dam foundation was completely replaced using a technique called dynamic compaction, and a grout curtain was installed below the foundation. The combination water release structure/bridge was also replaced. This work was completed in 1989 under authority of Reclamation's Safety of Dams Act making the full capacity available again. Project storage was increased by 1,700,000 acre-feet in 1927 with the completion of American Falls Dam, a 94-foot-high composite concrete and earth structure on the Snake River near American Falls, Idaho. A core-drilling program in the early 1960`s revealed that the concrete in portions of the dam was in a relatively advanced stage of deterioration due to a chemical reaction between alkalis in the cement and the aggregate. This type of reaction, unknown at the time of construction, resulted in a significant loss in strength and durability, threatening the competence of the dam. In the early 1970`s, storage was limited to 11.3 feet below full pool, which reduced the reservoir storage capacity to 1,125,000 acre-feet, about 66 percent of maximum design capacity. By congressional act of December 28, 1973, the American Falls Reservoir District, acting as the constructing agency representing the storage spaceholders, was authorized to finance and contract for the replacement of American Falls Dam. The new dam, completed in 1978, replaced the concrete portion of the original structure and was built immediately downstream from the old dam. During reconstruction the reservoir area was surveyed and the total storage capacity is now 1,672,600 acre-feet (active 1,672,600 acre-feet). The Upper Snake River Division of the project includes Island Park Dam, Cross Cut Canal and Diversion Dam, and Grassy Lake Dam. Island Park Dam is located 38 miles north of Ashton, Idaho, on Henrys Fork. The dam is a zoned earthfill structure 91 feet high. Water stored at Island Park and Grassy Lake Reservoirs is used in Fremont and Madison Counties in northeastern Idaho, and Teton County in Wyoming. Island Park Reservoir has a total storage capacity of 135,500 acre-feet (active 135,200 acre-feet) which includes 1 foot of surcharge that is filled on a recurring basis and is part of the allocated storage space. Safety of Dams modifications were completed at Island Park Dam in the early 1980's. This consisted of replacing the deteriorated concrete in the spillway and excavation and replacement of liquefiable materials in the right abutment. Water for irrigation in the Upper Snake River Division is diverted from Henrys Fork into the Cross Cut Canal by the Cross Cut Diversion Dam. The dam is a concrete weir which raises the water 10 feet above the streambed. Cross Cut Canal extends southeast from the diversion dam 6.6 miles to the Teton River. The canal furnishes irrigation water for 112,000 acres of land in Fremont and Madison Counties. This 118-foot-high zoned earthfill storage dam is on Grassy Creek in Wyoming near the southern boundary of Yellowstone National Park. The reservoir has a total storage capacity of 15,500 acre-feet (active 15,200 acre-feet) which supplements the storage at Island Park. Storage at Grassy Lake Dam is augmented by a 0.7-mile canal from Cascade Creek which is fed from the Cascade Creek Diversion Dam, a rockfilled log crib weir that is 14 feet high. Recent operation and maintenance modifications included the installation of a seepage blanket and drain at the toe of the dam in 1996 and 1997. Due to the poor condition of the spillway chute concrete, the reservoir has been restricted 1 foot below full capacity for the summer resulting in a storage capacity of 14,800 acre-feet. During the winter there is a 5-foot restriction resulting in a storage capacity of 13,655 acre-feet. Corrective action work is expected to be completed in the year 2000 at which time the operating restrictions will be rescinded. Because of these restrictions, no spillway releases are allowed. In 1928, construction began on the Gooding Division of the Minidoka Project. The work consisted primarily of building the Milner-Gooding Canal which heads at Milner Dam on the Snake River 12 miles west of Burley, Idaho. This 70-mile canal extends to the North Gooding Main Canal northwest of Shoshone, Idaho. The Milner-Gooding Canal and its connecting laterals furnish a full water supply for 20,000 acres and a supplemental supply for 78,667 acres. The initial capacity of the canal is 2,700 cubic feet per second. The North Side Pumping Division consists of some 77,000 acres of irrigable public land that have been withdrawn from entry, of which some 62,000 acres (Unit B) are irrigated by pumping ground water from deep wells, and 15,000 acres (Unit A) by pumping from the Snake River. A portion of the storage space in American Falls Reservoir, augmented by storage from Palisades Reservoir, is used to supply irrigation water to Unit A lands. Water for Unit A is pumped from the Snake River by a pumping plant located about 8 miles west of Burley. The plant capacity is 270 cubic feet per second and the dynamic head is 168 feet. The pumping plant delivers water to a 4.4-mile-long unlined canal that has the same capacity. Seven groups of deep wells, totaling 177 wells from 12 to 24 inches in diameter, initially supplied water for Unit B. The average discharge of these wells was about 6.4 cubic feet per second. Currently, 174 wells are being used. A distribution system consisting principally of unlined ditches distributes water in both units. The A & B Irrigation District, (operating agency of the North Side Pumping Division) in conjunction with the Bureau of Reclamation, has undertaken a program to enhance wetlands. The purpose of this program is to address the quality of runoff, both natural and irrigation return flows, which are injected into the aquifer by drainage wells, and to provide wildlife habitat and to allow reuse. Wetlands naturally filter water as it flows through the vegetation and provides a mechanism for increased natural recharge. Several wetland projects are completed and others are on-going. During replacement of American Falls Dam, the Idaho Power Company relocated its powerplant to take advantage of head that was previously wasted between the reservoir surface and the powerplant forebay, increasing the generating capacity to 112,400 kilowatts. In 1991, the Falls River Rural Electric Cooperative (FRREC) received a license from the Federal Regulatory Commission to construct and operate a small powerplant at Island Park Dam, located on the Henrys Fork of the Snake River. Generation from the 2-unit, 4,800 kilowatt plant began in 1994. FRREC also received approval in 1995 to modify the spillway of Island Park Dam with an adjustable lip to allow water that was previously spilled during irrigation surcharge to be passed through the powerplant to provide additional power generation. This modification, which is a 1-foot-high inflatable rubber collar, was completed in 1995. When Island Park Reservoir elevation is above 6302.0 feet, the rubber collar can be inflated or deflated to control spill. Operation of the rubber collar also improves water temperature conditions downstream in Henrys Fork, which benefits its rainbow trout fishery. The Gravity Division has been operated by the Minidoka Irrigation District since January 1, 1917; the South Side Pumping Division by the Burley Irrigation District since April 1, 1926; Gooding Division by American Falls Reservoir District No. 2 since May 1, 1933; and the Upper Snake River Division by Fremont-Madison Irrigation District since November 15, 1940. The North Side Pumping Division, last to be developed, was turned over to the A&B Irrigation District for operation on March 1, 1966. All storage and power facilities are operated by the Bureau of Reclamation.
Other
John Dooley, former Project Manager, Minidoka Project. Information received 6 June 1995. John Keys III, Regional Director of the Pacific Northwest Region, to Office of the Commissioner of Bureau of Reclamation. `PN Region Weekly Highlights,` 13 September 1995.
Contact
Contact
Title: Area Office ManagerOrganization: Upper Snake Field Office
Address: 470 22nd Street
City: Heyburn, ID 83336
Fax: 208-678-4321
Phone: 208-678-0461
Contact
Title: Public Affairs OfficerOrganization: Pacific Northwest Regional Office
Address: 1150 N Curtis Road, Suite 100
City: Boise, ID 83706-1234
Fax: 208-378-5019
Phone: 208-378-5020
Contact
Title: Public Affairs OfficerOrganization: Commissioner`s Office
Address: 1849 C Street NW
City: Washington, DC 20240
Fax: 202-513-0575
Phone: 202-513-0305