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 j I j ~N r ........ i/~ cJ: s' ) j ·' JI r 1,1;; - I ; I : < I Powerhouse w ,/ Dam/· ,~-..rQ&dP'• f Mystic Lake ( i <' I f - - _ 1-STILLWATERCOUNTYJ I CARBON COUNTY I 0 2 Miles I ~iiiiiiiiiiiiil I 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 N / t surge penstock chamber ./ I I / I ,/ powerhouse / I ,/ / ,r··r··-/ _______ /· / I / / : ) / I I / tunnel / <~ - _tra[L ,,-- I 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.