Haer No. Mt-130 Historic American Engineering

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:MYSTIC LAKE HYDROELECTRIC FACILITY HAER NO. MT-130 Along West Rosebud Creek Fishtail vicinity Stillwater County Also in Roscoe vicinity Carbon County 11ontana

WRITTEN HISTORICAL DATA

HISTORIC AMERICAN ENGINEERING RECORD lntermountain Support Office - Denver National Park Service P.O. Box 25287 Denver, Colorado 80225-0287 HISTORIC AMERICAN ENGINEERING RECORD MYSTIC LAKE HYDROELECTRIC FACILITY

HAER No. MT-130

I. INTRODUCTION

Location: The Mystic Lake Hydroelectric Facility is high in the Bitterroot Mountains, Stillwater County, south central Montana. The facility's dam is at the natural outlet to Mystic Lake, the headwaters of West Rosebud Creek. The Mystic Lake powerhouse lies nearly 2 miles downstream of the dam on a narrow terrace along the north bank of creek. The small community of Fishtail is about 17 miles northeast of the powerhouse.

Quad: Alpine, Emerald Lake, and Granite Peak (all 1996)

UTM: Zone 12: 597340 Easting, 5008549 Northing 597422 Easting, 5008525 Northing 598798 Easting, 5010634 Northing 599546 Easting, 5010573 Northing 599725 Easting, 5010658 Northing

Date of Construction: 1923-1937

Present Owner Pennsylvania Power and Light-Montana 45 Basin Creek Rd. Butte, Montana

Present Use: Hydroelectric generating plant

Significance: The Mystic Lake Hydroelectric Facility is significant for its association with the solidification and rapid development of Montana's electric power industry by The Montana Power Company. Mystic Lake was the first large-scale hydroelectric plant built in eastern Montana, and facility's production of AC current enabled Montana Power to meet ever-increasing demands for electricity at Billings and other smaller communities throughout the region. Mystic Lake is also significant as a well-preserved example of a state-of-the art hydroelectric plant of its day, and one that was designed and construction in the face of a multitude of challenges afforded by its remote, high-mountain setting. Mystic Lake has added engineering Mystic Lake Hydroelectric Facility HAER No. MT-130 Page 2

values as one of the first of only a few high head plants of high capacity ever built in Montana. Its powerhouse stands as an outstanding and somewhat rare example of Mission Revival industrial architecture as well.

Historian Renewable Technologies, Inc. 511 Metals Bank Bldg. Butte, MT 59701 October 2005 Mystic Lake Hydroelectric Facility HAER No. MT-130 Page 3

II. HISTORY

A. Introduction

The Mystic Lake Hydroelectric Facility is in the West Rosebud Creek drainage on the eastern flank of the Beartooth Mountains of south central Montana. The small community of Fishtail is about 17 miles northeast of Mystic Lake, Columbus is another 38 miles or so to the north-northeast, and Montana's largest urban center, the City of Billings, lies some 40 miles east of Columbus (Figure 1). Major components of the hydroelectric generating plant include: a concrete arch storage dam at the natural outlet to Mystic Lake; an intake structure on the lakeshore west of the dam, the powerhouse which lies nearly two miles downstream (northeast) of the intake; and a multi-component water delivery system that carries water from the intake to the powerhouse's two hydroelectric generating units (Figure 2). A variety of support and maintenance structures, both modem and historic, are found at the facility, as well as along with a camp of permanent-type residential facilities for the plant's operational personnel.

Segments of two transmission lines, the A Line and B Line, are also associated with Mystic Lake Hydroelectric Facility. These segments run side-by-side from the powerhouse at Mystic Lake to the Line Creek switchyard, a total distance of about 51/z miles.

B. Background to The Montana Power

In late 1912 and early 1913, Montana's three major electric utilities and their subsidiaries merged to form The Montana Power Company. The consolidation provided the new company control over most of the electric power market and infrastructure in the state. The major consumers of electricity in that power market at the time were concentrated in the western Montana. Top of among those by a wide margin were the great copper mines at Butte and reduction works at Anaconda, the state's major industrial core. 1

Having secured a large market base and necessary capital, Montana Power swiftly expanded its electric power generating capacity and transmission capabilities. At the time of its formation in 1912-13, the company had 13 power generation plants (both hydro and steam) and 1200 miles of transmission lines. The backbone of its generation plants consisted of a string of hydroelectric facilities on the Madison-Missouri River system in western Montana, including: Madison No. 1 and 2, Canyon Ferry, Hauser, Black Eagle and Rainbow.2 Soon thereafter, most of

1 Renewable Technologies, Inc., "NPS Form 10-900-B: Hydroelectric Generating Facilities on the Missouri and Madison Rivers in Western Montana," in Missouri-Madison Hydroelectric Project FERC Project No. 2188 Cultural Resource Management, Plant Operating Facilities and a Private Recreation Camp, Evaluations of Eligibility for Listing in the National Register ofHistoric Places (Butte: Montana Power Company, 1991): El-E6.

2 Cecil Kirk, "History of Montana Power," 3 vol., n.d., unpublished report, Butte, vol. 2: chapter 9: pp. 4- 5. Because this three-volume history, divided into 14 chapters, has inconsistent pagination, citations will refer to volume: chapter: and page(s). Mystic Lake Hydroelectric Facility HAER No. MT-130 Page4

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Figure 1. Map showing location of the dam and powerhouse at the Mystic Lake Hydroelectric Facility. Mystic Lake Hydroelectric Facility HAER No. MT-130 Page 5

/ t surge penstock chamber ./ I

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Mystic Lake dam 0~~iiiiiiiiiiiiiii- 1000 2000 Feet 0~~---iiiiiiiiiiiiiii 0.2 0.4 Miles

Figure 2. Map of major resources at Mystic Lake Hydroelectric Facility. Mystic Lake Hydroelectric Facility HAER No. MT-130 Page 6 those hydroelectric facilities were upgraded and larger, more technologically advanced new plants were constructed. The latter included Thompson Falls on the Clarks Fork River, and Holter and Ryan on the Missouri. With the new plants and upgrades, the company more than doubled its electrical generating capacity between 1912 and 1918. During that same period, the total number of miles of transmission lines grew to nearly 2000. 3 One contemporary federal report concluded that "no better service is given and no lower rates charged" than in Montana.4

Montana Power's rapid expansion in the 191 Os benefited industrial development in Montana as well as the small consumer market. Ample and inexpensive power enabled the modernization of the copper industry at Butte and Anaconda. It also allowed for the electrification of the Butte, Anaconda & Pacific and the Milwaukee Road railroads. Meanwhile, the company had extended service to nearly 50 towns, including numerous rural communities previously without electrical power. 5

C. Mystic Lake Hydroelectric Facility

Compared with that of western Montana, the early growth of the electric industry in eastern Montana progressed slowly. The first electrical generating facility of note in the region was simply a water-powered dynamo that supplied electricity to merchants, other commercial enterprises to the largest city in the region, Billings. As of 1890, the city only had a population of only 836, thus the demand for power was comparatively minimal and almost exclusively for lighting purposes. When Billings' population increased four-fold between 1890 and 1900, it fostered a demand for electricity for power instead of just lighting. In response, the two major electric utilities in Billings both constructed small hydroplants on the Yellowstone River in 1906. Additionally, the owner and operator of western Montana's Madison hydroelectric plants at the time began erecting a 50 Kv transmission line from Madison towards eastern Montana. That line finally reached Billings in 1910, and immediately became the city's major supplier of electrical power. 6

After acquiring the assists of the major electric utilities at Billings, Montana Power officials began considering construction of a major hydroelectric facility in eastern Montana. By late 1913, company engineers had investigated three potential sites, with the most promising of those being Mystic Lake in the Beartooth Mountains, about 80 miles southwest of Billings. Stopped first by emphasis on other system priorities and then by World War I, Montana Power did

3 Montana Power Company, The Story ofMontana Power, 49, 54 4 Quote cited in Carrie Johnson, "Electrical Power, Copper, and John D. Ryan," Montana: The Magazine of Western History 38 (Autumn 1988): 33. 5 Montana Power Company, The Story ofMontana Power, 48-51.

6 Kirk, "HistoryofMontanaPower," 1: 5: 2-8, 11-12. Mystic Lake Hydroelectric Facility HAER No. MT-130 Page 7 not make a firm commitment to go forward with the Mystic Lake project until 1921. By then, C. T. Main, a large Boston-based hydroelectric engineering company, had completed the design for the high-head facility. 7

Mystic Lake presented a unique setting for a Montana Power hydroelectric development. For all the company's earlier installations, rivers were dammed to create a large pool or reservoir where none had been before. At Mystic Lake, the reservoir was essentially already there in the form of a natural lake at the head of West Rosebud Creek high in the Beartooth Mountains. Montana Power intended to take advantage of this ready-made reservoir, but there was no question that the hydroplant could not stand at the reservoir's edge. Upper West Rosebud Creek immediately below the lake's outlet traversed very steep and rugged terrain. In fact, at one point it formed a spectacular falls. At about 1% miles below the outlet and 1200 feet lower in elevation, the valley opened up slightly to about 11,i mile wide. This location seemed to be the only reasonable site for the powerhouse and associated operators' camp. The relative positions of the reservoir and powerhouse site in this dramatic setting essentially dictated a high head plant. 8

Actual construction of the facility began in 1923 with installation of a 50 K v electric powerline from Red Lodge to the worksite. Among the first major construction project complete after that was the installation of an incline railroad. This was used to move supplies and men from the construction camp and materials stockpile site near the future powerhouse to Mystic Lake and all points between.9

After nearly two years of construction, the Mystic Lake Hydroelectric Facility came on line in late March 1925. At the time, the plant used water naturally "stored" in Mystic Lake. Water was drawn through a 1000-foot long tunnel near the natural outlet of the lake, and from there ran into a 9000-foot-long wood-stave flow line. At the end of the line, the water passed through a T-connection with one end leading to a Johnson ( or differential) surge tank and the other to a 2732-foot-long penstock. Prior to entering the powerhouse, the penstock split into two smaller penstocks, each of which delivered water to a Pelton impulse wheel. Designed for high-head facilities, the 7500-horsepower Pelton wheels at Mystic were manufactured by the Pelton

7 Ibid., 1: 5: 18-19, 27; Montana Power Company, "Initial Statement of the Montana Power Company to the Federal Power Commission showing Actual Legitimate Original Cost and Estimated Accrued Depreciation of Mystic Lake Hydroelectric Project, Project No. 2301 Located in the State Montana as of December 1, 1961," (Butte: self-published, 1965): 4, on file, Box Hydro 74, PPL-Montana, Butte.

8 "Eastern Montana to Benefit from New Power Project," The Anaconda Standard, 12 November 1922, Part III, p. 1. 9 Kirk, "History of Montana Power," 1: 5: 14, 18-9, 22, 24-5; Montana Power Company, "Initial Statement of the Montana Power Company," 4, 53; "Report of the Montana Power Company for the Year Ended December 31 '\ 1922," 28 February 1923, on file, Montana Historical Society Library and Archives, Helena [subsequent citations for documents at the Montana Historic Society Library and Archives will abbreviate the repository as "MRS"]; "M.E. Buck Tells Engineers the Marvelous Story of Mystic Lake Power Plant," unknown newspaper, 14 April 1925, clipping on file, Mystic Lake folder, vertical file, MRS. Mystic Lake Hydroelectric Facility HAER No. MT-130 Page 8

Waterwheel Company which had altered the needle valves to reduce water hammer, at the direction of Montana Power. They were attached to two horizontal, revolving-field generators, each rated at 6250 kva. 10 The powerhouse itself was a reinforced concrete building rendered in the Mission Revival style which was popular in the United States at the time, but more commonly for residential rather than industrial structures. 11

Montana Power had planned all along to build a dam across the natural outlet of Mystic Lake, but chose to add that piece of the facility in 1926. In that year, the company built a 420- foot-long concrete arch dam across the old outlet, raising the lake level by 15-20 feet. It also erected a smaller, 145-foot-long earthfill embankment or dike at a low spot to prevent the lake from overflowing the intake area and damaging the rail line. 12 At completion, Mystic Lake had an effective head of 1010 feet, making this facility not only the first high-head plant in the Montana Power system but also the plant with the highest head (at the time of construction) in Montana or the nearby states of Idaho, Oregon, and Washington. 13

When the hydroelectric plant first came on line, the 50 Kv transmission line used during project construction took on a new role, that of a transmission facility for the plant's production of high voltage AC electrical power to Red Lodge. Five years later, in January 1930 Montana Power completed construction of a second 50 K v transmission line out of the plant. Rather than Red Lodge, this new "B Line" interfaced with Montana Power's electric power grid at Columbus, some 45 miles north of Mystic Lake. 14

Through the late 1920s and 1930s, Montana Power continued to add to the stock of support and maintenance facilities at the hydroelectric plant at Mystic as well as the operators' camp. Among many others, these additions, for example, included a domestic water supply system serving both the powerhouse and the operator's camp and a small house at the lake for use by project personnel assigned to care for the dam, intake structure and the upper end of the flowline.

1° Kirk, "History of Montana Power," 1: 5: 25-6; Buck, "Rocky Mountain Hydro-Electric Plant"; "M.E. Buck Tells Engineers." 11 Virginia and Lee McAlester, A Field Guide to American Houses (New York: Alfred A. Knopf, 1984): 409. 12 Kirk, "History of Montana Power," 1: 5: 27; Montana Power Company, "Initial Statement of the Montana Power Company," 2. 13 "Tunnel Taps Mystic Lake Below Water Surface," Engineering News-Record 96, no. 16 (22 April 1926): 642-3. Flint Creek, another high-head plant with Pelton wheels, was built in 1900, but not acquired by Montana Power until 1935: Fredric L. Quivik and Mark T. Fiege, "Flint Creek Powerhouse and Dam: A Determination of Eligibility for the National Register of Historic Places," (Butte: Renewable Technologies, Inc., 1987): 18, prepared for Montana Power Company, Butte; "Hydraulic Drop of 1100 Feet Feature of Unique Water Power Project," The Grass Range Review, [1923], undated clipping on file, Mystic Lake folder, vertical file, MHS. 14 Cecil Kirk, "History of Montana Power," vol. 1: chapter 5: p. 36; Gene Braun, telephone interview with Mary McCormick, September 2005. Mr. Braun headed the electric transmission and distribution section of Montana Power Company's engineering department before his retirement in the 1990s. Mystic Lake Hydroelectric Facility HAER No. MT-130 Page 9

Company employees conducted landscaping work in the vicinity of the powerhouse and operators' camp, including the planting of trees and lawns, erection of dry-laid rock retaining walls, and the installation of a cast iron fountain. 15

Several changes were made to the Mystic Lake industrial plant in the decades after War World IL Among the more significant changes have been a series of alterations to the wood-stave flowline dating between the early 1950s and 1990. Ultimately, the entire line was replaced with steel pipe. 16

The Mystic Lake Development remained part of Montana Power's system of generating plants and transmission and distribution lines until September 1999. At that time, the company sold Mystic Lake and most of its other electric generating plants to Pennsylvania Power and Light Montana (PPL-Montana). In addition to the hydroelectric plant, the sale of facilities at Mystic Lake included the first 5Yz miles or so each of the A and B transmission lines, or that segment of the lines from the plant to a switchyard on Line Creek. Operations at Mystic Lake have continued under PPL-Montana to the present.

III. BIBLIOGRAPHY

Braun, Gene. Telephone interview with Mary McCormick. September 2005.

Buck, M.E. "A Rocky Mountain Hydro-Electric Plant." Electrical World 87, no. 6: 288-90.

"Eastern Montana to Benefit from New Power Project." The Anaconda Standard. 12 November 1922.

"Hydraulic Drop of 1100 Feet Feature of Unique Water Power Project." The Grass Range Review, [1923]. Undated clipping on file, Mystic Lake folder, vertical file, Montana Historical Society Library and Archives, Helena.

Johnson, Carrie. "Electrical Power, Copper, and John D. Ryan." Montana: The Magazine of Western History 38 (Autumn 1988): 24-37.

15 Montana Power Company, "Insurance Map of Mystic Lake," 1939, Drawing 040104-024215-B-1-0-0A- 122/215, on file, PPL-Montana, Butte; "Initial Statement of the Montana Power Company," 9, 20; "1941 Valuation, Electric. Dept., Power Plant Structures, Summary Notes, Vol. 7[Mystic Lake]," Account 321, 12 December 1941, pp. 345-347, on file, Box WH-20-76, MHS; "1941 Valuation, Electric Dept., Production Equipment, Mystic Lake, Field Notes, Vol. 40," 9 October 1941, pp. 256,268, on file, Box WH-20-40, MHS; Cecil Kirk, Grounds and Improvements, in Montana Power Company, "Engineering Check of Cost Analysis," [Mystic Lake, ca. 1941], on file, Box WH-21-23, MHS. 16 James V. Leishman, "Replacement of Mystic Lake Pipe Line, Construction Report 1958," (Butte: Montana Power Company, 1958); Gary Peterson, "Final Completion Report for Mystic Lake Flowline Replacement Phase II - 1990," (Butte: Montana Power Company, 1990) both on file, PPL Montana, Butte; PPL-Montana, "Mystic Lake Dam; Plan, Profile, & Details ofFlowline," 2000), Drawing 43379-D21-6-0-3, on file, PPL-Montana, Butte. Mystic Lake Hydroelectric Facility HAER No. MT-130 Page 10

Kirk, Cecil. "Engineering Check of Cost Analysis," [Mystic Lake, ca. 1941]. On file, Box WH-21- 23, Montana Historical Society Library and Archives, Helena.

"History of Montana Power," 3 volumes. Unpublished report, Butte, n.d.

Leishman, James V. "Replacement of Mystic Lake Pipe Line, Construction Report 1958." Butte: Montana Power Company, 1958. On file, PPL-Montana, Butte.

"M.E. Buck Tells Engineers the Marvelous Story of Mystic Lake Power Plant." Unknown newspaper. 14 April 1925. Clipping on file, Mystic Lake folder, vertical file, Montana Historical Society Library and Archives, Helena.

McAlester, Virginia and Lee. A Field Guide to American Houses. New York: Alfred A. Knopf, 1984.

Montana Power Company. "Initial Statement of The Montana Power Company to the Federal Power Commission showing Actual Legitimate Original Cost and Estimated Accrued Depreciation of Mystic Lake Hydroelectric Project, Project No. 2301 Located in the State Montana as of December 1, 1961." Butte: by author, 1965. On file, Box Hydro 74, PPL-Montana, Butte.

"Insurance Map of Mystic Lake," 1939. Drawing 040104-024215-B-1-0-0A-122/215. On file, PPL-Montana, Butte

"1941 Valuation, Electric. Dept., Power Plant Structures, SummaryNotes, Vol. 7 [Mystic Lake]," Account 321. On file, Box WH-20-76, Montana Historical Society Library and Archives, Helena.

"1941 Valuation, Electric Dept., Production Equipment, Mystic Lake, Field Notes, Vol. 40." 9 October 1941. On file, Box WH-20-40, Montana Historical Society Library and Archives, Helena.

"Report of the Montana Power Company for the Year Ended December 31 5\ 1922." 28 February 1923. On file, Montana Historical Society Library and Archives, Helena

__ . The Story ofMontana Power. Butte: Montana Power Company, 1941.

"Tunnel Taps Mystic Lake Below Water Surface." Engineering News-Record 96, no. 16 (22 April 1926): 642-43.

Peterson, Gary. "Final Completion Report for Mystic Lake Flowline Replacement Phase II- 1990." Butte: Montana Power Company, 1990. On file, PPL-Montana, Butte. Mystic Lake Hydroelectric Facility HAER No. MT-130 Page 11

PPL-Montana. "Mystic Lake Dam; Plan, Profile, & Details of Flowline." 2000. Drawing 43379- D21-6-0-3. On file, PPL-Montana, Butte.

Quivik, Fredric L. and Mark T. Fiege. "Flint Creek Powerhouse and Dam: A Determination of Eligibility for the National Register of Historic Places." Butte: Renewable Technologies, Inc., 1987. Prepared for Montana Power Company, Butte.

Renewable Technologies, Inc. "Missouri-Madison Hydroelectric Project FERC Project No. 2188 Cultural Resource Management, Plant Operating Facilities and a Private Recreation Camp, Evaluations of Eligibility for Listing in the National Register of Historic Places." Butte: Montana Power Company, 1991.