Holter Dam is a hydroelectric straight gravity dam on the Missouri River about northeast of Helena, Montana, in the United States.Upper Missouri River Reservoir Fisheries Management Plan, 2010-2019, Montana Department of Fish, Wildlife and Parks, May 13, 2010, p. 11. The dam, which was built between 1908 and 1918, is long and high.Aarstad, et al., Montana Place Names From Alzada to Zortman, 2009, p. 125. The reservoir formed by the dam, Holter Lake (also known as Holter Reservoir) is long and has a storage capacity of of water when full. The dam is a "run-of-the-river" dam because it can generate electricity without needing to store additional water supplies behind the dam.Upper Missouri River Reservoir Fisheries Management Plan, 2010-2019, Montana Department of Fish, Wildlife and Parks, May 13, 2010, p. 9.Badovinac, Fly Fishing: Montana's Missouri River, 2003, p. 17.
Dam and lake
Holter Dam Holter Dam was built by the United Missouri River Power Company and the Montana Power Company. Samuel Thomas Hauser, a former Territorial Governor of the state of Montana from 1885 to 1887, had had a lengthy career in banking, mining, railroads, ranching, and smelting, but had encountered a series of financial setbacks after the Panic of 1893 which had nearly ruined him financially.Goodspeed, The Province and the States ... , 1904, p. 452-454.Shearer, Louisiana to Ohio, 2004, p. 708. In his early 60s, Hauser began to rebuild his finances by branching out into the relatively new industry of hydroelectric power generation. In 1894, he formed the Missouri River Power Company, and won the approval of the United States Congress to build a dam below Stubbs' Ferry (which later was known as Hauser Dam). In 1905, Hauser and other directors of the Missouri River Power Company formed the Helena Power Transmission Company (also known as the "Helena Power and Transmission Company").King, "Annual Address," Journal of the Association of Engineering Societies, March 1906, p. 103. The two companies merged on February 16, 1906, to form the United Missouri River Power Company.Murphy, The Comical History of Montana: A Serious Story for Free People, 1912, p. 267. The merged company completed Hauser Dam on February 12, 1907.Hall, Montana, 1912, p. 135. The dam was a steel dam built on masonry footings on top of gravel, with the ends of the dam anchored in bedrock on either side of the river. On April 14, 1908, Hauser Dam failed after water pressure undermined the masonry footings (the steel dam itself being structurally sound).Jackson, Dams, 1997, p. 65-66; Wegmann, The Design and Construction of Dams, 1918, p. 198. United Missouri River Power began reconstruction of Hauser Dam in July 1908 (completing the dam in the spring of 1911).
The United Missouri River Power Company had begun construction of Holter Dam in 1908 before the failure of Hauser Dam.Clary, Lewis & Clark on the Upper Missouri, 1999, p. 141. Hauser had conceived of a dam at the present location in 1906 to supply the newly formed Amalgamated Copper Mining Company (a forerunner to Anaconda Copper) with electricity."Holter Hydroelectric Facility," HAER No. MT-94-A/HAER MONT 25-WOCRE-1A, Historic American Engineering Record, National Park Service, November 1994, p. 2. The dam was named for Anton Holter, president of the Helena Transmission Power Company and by 1908 a director of the United Missouri River Power Company.Axline, Conveniences Sorely Needed: Montana's Historic Highway Bridges, 1860-1956, 2005, p. 34. Hauser formed a subsidiary, the Capital City Improvement Company, to seek investment money and build the dam for the power company. John Ripley Freeman was the dam's design engineer (he also worked on the Hetch Hetchy Aqueduct, the Charles River Dam, the Keokuk Dam, the Los Angeles Aqueduct, and the Panama Canal).Mount, Sci-Tech Archives and Manuscript Collections, 1989, p. 49; Jackson, Building the Ultimate Dam: John S. Eastwood and the Control of Water in the West, 2005, p. 285, fn. 33. Stone & Webster, a Boston-based firm, was the construction company. But cost overruns, waning investor enthusiasm, and the liability associated with the collapse of Hauser Dam nearly drove Samuel Hauser (United Missouri's largest shareholder) into bankruptcy.Clary, Lewis & Clark on the Upper Missouri, 1999, p. 137. Amalgamated Copper, which bought 75 percent of United Missouri's power and owned $1 million of its corporate bonds, now began buying its power from Hauser's rival, John D. Ryan's Great Falls Power Company.Robbins, Colony and Empire: The Capitalist Transformation of the American West, 1994, p. 118. Construction on Holter Dam was halted in late 1910 after only part of the foundation had been poured."Holter Hydroelectric Facility," HAER No. MT-94-A/HAER MONT 25-WOCRE-1A, Historic American Engineering Record, National Park Service, November 1994, p. 2, 5. Hauser sold his interest in United Missouri River Power to Ryan, who on October 25, 1912, merged United Missouri River Power with the Butte Electric and Power Company, Billings and Eastern Montana Power Company, and Madison River Power Company to form the Montana Power Company.Malone, The Battle for Butte: Mining and Politics on the Northern Frontier, 1864-1906, 2006, p. 204. Montana Power took over not only United Missouri's Canyon Ferry Dam and Hauser Dam but the partially built Holter Dam as well.
Montana Power resumed building the structure in March 1916."Holter Hydroelectric Facility," HAER No. MT-94-A/HAER MONT 25-WOCRE-1A, Historic American Engineering Record, National Park Service, November 1994, p. 5."Montana Power Earnings Show Great Business Growth," Electrical World, April 28, 1917, p. 817. The reason for resuming construction was to supply power to the Butte, Anaconda and Pacific Railway and the Chicago, Milwaukee, and St. Paul Railroad. The Chas. T. Main company (whose Western Office was in Butte, Montana) was hired to revisit the design. Henry A. Herrick, an employee of the power company, was the consulting engineer for Main.In addition to his work on Holter Dam, Herrick also worked on the reconstructed Hauser Dam, Thompson Falls Dam, and Hebgen Dam. See: "Report of Committee on Memorials," Proceedings of the Second War Convention, National Electric Light Association, 1918, p. 357. The major change implemented by Main and Herrick was to install vertical rather than horizontal turbines, although some changes were made to the wastewater system and the dam's downstream face. Stone & Webster continued to be the construction company,United States Shipping Board Emergency Fleet Corporation. ... 1918, p. 2370. and more than 500 men worked on the project. The S. Morgan Smith Company of York, Pennsylvania, designed the water wheels for the turbines. The 1916-1918 construction camp was the largest ever built by Montana Power."Holter Hydroelectric Facility," HAER No. MT-94-A/HAER MONT 25-WOCRE-1A, Historic American Engineering Record, National Park Service, November 1994, p. 6. There were more than 115 buildings at the construction site, including a bunkhouse and dormitories for unmarried men, cottages for married men, a dining hall, a bathing house, storage sheds, garages, a photography studio, school, hospital, and sewer. Although most of the structures were tents or wooden buildings intended for short-term use, seven of the structures were renovated into permanent housing for the dam's operators. Two more homes were built for operators after construction ended."Holter Hydroelectric Facility," HAER No. MT-94-A/HAER MONT 25-WOCRE-1A, Historic American Engineering Record, National Park Service, November 1994, p. 7. Montana Power spent $1.3 million in 1916 and $1.5 million in 1917 to finish the dam. Holter was completed and brought online for power generation in 1918. It was the sixth and last dam completed by the company in that decade.Grant, International Directory of Company Histories, 2007, p. 289.
In its original configuration, Holter Dam was expected to be long and high, but ended up being slightly larger. At the time, Holter was the tallest hydroelectric dam on the Missouri River. The penstocks are below the water level when the reservoir is full. The dam had four vertical single-runner 15,000-horsepower water turbines, seven main electrical generators and three exciters,"The Capital City Power Plant of the United Missouri River Power Company," Engingeering News, June 1910. and was capable of generating 40,000 kilowatts of power. Aside from the powerhouse and water intakes, the dam has three sections: a central section where water is permitted to flow over the dam, and a left and right section anchored to the bedrock where water is not able to flow over the dam. The dam incorporated flashboards into the crest of the dam to permit overflow.Flashboards are a system of wooden or metal panels which can be raised or lowered to allow excess water to pass over the crest of the dam. A series of metal frames holds the flashboards in place. Placing more than one flashboard on top of the other allows the dam's height to be temporarily raised. Raising the flashboard can permit water to pass beneath the flashboard and over the dam, alleviating stress on the dam. The higher the flashboard is raised, the more water passed beneath and over the dam. The dam has 31 flashboards, each of them high.Dennison, "A New Plan for Holter Dam Repairs," Great Falls Tribune, May 25, 2000; "PPL Montana Says Repairs to Holter Dam Will Cause Minimal Disruption," Associated Press, May 25, 2000.Newhouse, "Anglers Praise Holter Dam Repairs," Great Falls Tribune, September 18, 2000.
As of 1994, Holter Dam, its powerhouse, its nearby operator housing and abandoned construction camp, its railroad switchyard, and the nearby maintenance buildings are one of the most intact historic hydroelectric generating facilities in Montana."Holter Hydroelectric Facility," HAER No. MT-94-A/HAER MONT 25-WOCRE-1A, Historic American Engineering Record, National Park Service, November 1994, p. 1.
Holter Lake
Holter Dam raised the water level behind it by about ,Johnsgard, Lewis and Clark on the Great Plains: A Natural History, 2003, p. 129. creating the long Holter Lake (also known as Holter Reservoir). Holter Lake has a surface area of . The lake has a mean depth of and a maximum depth of .Upper Missouri River Reservoir Fisheries Management Plan, 2010-2019, Montana Department of Fish, Wildlife and Parks, May 13, 2010, p. 7. Holter Lake stores of water when full. The distance between Hauser Dam and Holter Lake is .
The Missouri River runs free for between Holter Dam and the five dams at Great Falls, Montana.Sample, Fishing Montana: An Angler's Guide to the Big Sky's Best Streams and Lakes, 1998, p. 126.
Geology beneath and around Holter Dam Madison Limestone forms much of the surface rock through which the Missouri River flows at Holter Dam. The limestone is rich in fossils, mostly brachiopods like clams, mussels, and mollusks. Holter Lake sits atop the Eldorado thrust fault, which juxtaposes Proterozoic Belt Supergroup Greyson Shale over much younger Madison Limestone and is part of the Sevier orogeny.Sears and Hendrix, "Lewis and Clark Line and the Rotational Origin of the Alberta and Helena Salients, North American Cordillera," in Orogenic Curvature: Integrating Paleomagnetic and Structural Analyses, 2004, p. 179-180.
Gates of the Mountains
Holter Lake has two parts, dubbed upper Holter Lake and lower Holter Lake. The central section of the lake is a narrow, neck, marked at its downstream end by the Gates of the Mountains.Miller, The Complete Paddler: A Guidebook to the Missouri River From the Headwaters to St. Louis, 2005, p. 85. The Gates of the Rocky Mountains were first recorded when the Lewis and Clark Expedition passed through the area in 1805. Captain Meriwether Lewis wrote on July 19, 1805:Quoted in Wright, Montana Places: Exploring Big Sky Country, 2000, p. 63.