SHOSHONE FALLS HYDROELECTRIC PROJECT, CLIFF HAER 10-45-1 SUBSTATION & WAREHOUSE /0-45-1 (Building No. 285) North Bank of Snake River, halfway between the Intake and powerhouse complex Tipperary Corner vicinity Jerome Idaho PHOTOGRAPHS WRITTEN HISTORICAL AND DESCRIPTIVE DATA HISTORIC AMERICAN ENGINEERING RECORD PACIFIC WEST REGIONAL OFFICE National Park Service U.S. Department of the Interior 1111 Jackson Street, Suite 700 Oakland, CA 94607 HISTORIC AMERICAN ENGINEERING RECORD SHOSHONE FALLS HYDROELECTRIC PROJECT, CLIFFS SUBSTATION AND WAREHOUSE (Building No. 285) HAER NO. ID-45-I Location: The Cliff Substation is located at approximately half way between the Intake and the powerhouse complex, on the cliff side below the powerhouse access road but above the powerhouses. Building No. 285 is located along the eastern edge of the substation, partially inside the substation fence. USGS Twin Falls, Idaho Quadrangle, UTM Coordinates: Cliff Substation: 713037mE, 4719421mN; Building No. 285: 713045E, 4719408mN. Dates of Construction: 1928 Engineer: W.G. Hamilton (Sponsor Engineer, Electric Bond & Share Co.) Builder: Phoenix Construction Company, Phoenix Present Owner: Idaho Power Company 1221 West Idaho Street Boise, Idaho 83702 Present Use: Hydroelectric Power Generation Significance: The Cliff Substation, rated at 138 kV is an original component of the Idaho Power Company's 1920s expansion of the Shoshone Falls Hydroelectric Project to meet growing demand for electricity. Transmission lines connected the substation to the Idaho Power Company's American Falls Hydroelectric Project electric grid in 1927, thereby giving the company the flexibility to meet peak locational demand for the first time in its history. Building No. 285 was the fifth building constructed by at the Project in 1928 by the Idaho Power Company as part of its expansion of the facility's capacity. This small, stucco­ sided building provided storage for equipment used at the Cliff Substation and the Shoshone Substation/Switchyard. Historian: Sheri Murray Ellis, May 2007. James W. Steely, May 2007. SHOSHONE FALLS HYDROELECTRIC PROJECT, CLIFFS SUBSTATION & WAREHOUSE (Building No. 285) HAER NO. ID-45-1 (Page 2) Project Information: Between May and December 2007, SWCA Environmental Consultants documented the hydroelectric complex, under guidance of the Historic American Engineering Record (HAER). Project manager Sheri Murray Ellis (SWCA) coordinated with historian and photographer James W. Steely to complete the HAER documentation. Archives for the Shoshone Falls Hydroelectric Project are located at the Idaho Power Company (IPC) headquarters in Boise, Idaho, and at the public library in Twin Falls, Idaho. Records from the IPC archives were provided to SWCA by Mr. Shane Baker, Senior Archaeologist for IPC. SHOSHONE FALLS HYDROELECTRIC PROJECT, CLIFFS SUBSTATION & WAREHOUSE (Building No. 285) HAER NO. ID-45-I (Page 3) Historic and Engineering Context: The Shoshone Falls Hydroelectric Project 1) encompasses a unique tunnel and penstock system that was constructed with great effort in a remote landscape; 2) was adapted to the severe environmental constraints created by the deep and narrow Snake River Gorge; 3) captured a natural water source and used innovative design methods to generate substantial hydroelectric power out of a precipitous elevation change in the Snake River; 4) is an early and enduring example of a high-head hydroelectric complex in Idaho; 5) made significant contributions to the development and expansion of the electrified irrigation system of the Twin Falls/Magic Valley region; and 6) has operated continuously for at least 100 years. Additionally, the facility has made significant contributions to the development and maintenance of the local tourism industry; Idaho Power Company, current operator of the hydroelectric project, has entered into an agreement with local municipalities to provide a minimum of 300 cubic feet per second of water flow over Shoshone Falls, a popular tourist site, during the yearly tourist season. Character Defining Attributes The Cliff Substation is located above the powerhouse complex, immediately below and adjacent to the powerhouse access road. The substation was constructed around 1927 as part of the Idaho Power Company's (IPC) connection of transmission lines between the Shoshone Falls Project and the American Falls Project1 and is the largest of the three substations associated with the Project and is the main distribution station for the facility. Overview of Cliff Substation; view to the south-southwest. Photo taken One bank of four Westinghouse ,__M_a_Y_2_0_07_· ____________________. single phase, 46 kV to 138 kV transformers with fans is located in the southwest corner of the station, and a trio of 138 kV oil circuit breakers is located in the northeast corner of the yard. A simple riveted steel superstructure, which consists of two parallel rows of three towers joined to each other by steel cross-members, supports several current transformers that feed a series of transmission lines as well as several suspension insulators. 1 Stacy, Susan M. 1995. Shoshone Falls Power Plant: A Reconnaissance-Level Survey of Historic Structures for Shoshone Falls Hydroelectric Project FERC #2778. Prepared for Idaho Power Company, Boise. SHOSHONE FALLS HYDROELECTRIC PROJECT, CLIFFS SUBSTATION & WAREHOUSE (Building No. 285) HAER NO. ID-45-I (Page 4) A standard gauge rail track is located in the substation yard, extending from near the northwestern perimeter fence to the southeast side of the yard. The track passes to the north of the transformer bank and terminates adjacent to a raised (16-inch tall) concrete pad with a short length of track extending across it to the north. A riveted steel scaffolding/superstructure straddles the pad and houses a small hoist. The track system serves for transporting heavy equipment into and out of the Oil circuit breakers; view to the southeast. Photo taken May 2007. substation yard and aides in placement of items such as transformers within the yard. Rail track in Cliff Substation yard; view to the southeast. Photo taken May 2007. SHOSHONE FALLS HYDROELECTRIC PROJECT, CLIFFS SUBSTATION & WAREHOUSE (Building No. 285) HAER NO. ID-45-I (Page 5) Overview of Cliff Substation location (lower right and center) ca. 1921, prior to the construction of the substation. Photo courtesy of Idaho Power Company. Associated Structures In addition to the power distribution component of the substation, two small buildings are associated with the Cliff Substation. One has been designated as Building 285, and the other does not appear to have a specific designation as it is identified as a structure rather than a building for Idaho Power Company's management purposes. For the purpose of description, it will be referred to as the oil tank building. Warehouse (Building No. 285) Building No. 285; view to the east-northeast. Photo taken May 2007. The warehouse (Building No. 285) is located along the southeastern perimeter of the substation complex. Constructed in 1928 under the auspices of IPC, the building is a small, rectangular plan structure with a low-pitched hipped roof and a cast-in-place concrete and wooden beam foundation. The building has a SHOSHONE FALLS HYDROELECTRIC PROJECT, CLIFFS SUBSTATION & WAREHOUSE (Building No. 285) HAER NO. ID-45-I (Page 6) wooden 2x4 frame that is covered in concrete mesh and clad in stucco/plaster siding. A small section of the plaster in the southeastern corner of the building has been replaced with horizontal plywood planking. The roof of the building is clad in wood (cedar) shingles, and the open eaves are characterized by exposed rafter tails. The building, which served as a warehouse and equipment storage structure for the Cliff Substation measures approximately 24 feet long by 9 Building No. 285, warehouse; view to the southeast. Photo taken May feet 6 inches wide and stands an 2007. estimated 15 feet tall. .__ ______________________....1 The west elevation of the building constitutes its principal fac_;ade. A single entryway is present in this elevation. No windows are present. The entryway is located north of center in the elevation. It measures approximately 11 feet tall by 5 feet 6 inches wide and holds a batten door mounted on an overhead sliding track attached to the interior of the building. The door is composed of wood and steel framing, diagonal tongue-and-groove planking, and milled lumber cross-braces. The north and south elevations are symmetrical, each containing a single window opening. The openings are situated at center in the elevations and are rectangular in shape, with the long axis oriented vertically. The openings measure 2 feet 10 inches wide by 5 feet 2 inches tall and have wooden sills. At the time of documentation, the openings held what appear to be the original wood frame, one-over-one, single-hung windows. The east elevation of the building is built up against an adjacent cliff face and could not be inspected for Building No. 285, warehouse; close up of wall construction and foundation detail. Photo preparation of an architectural description. taken May 2007. SHOSHONE FALLS HYDROELECTRIC PROJECT, CLIFFS SUBSTATION & WAREHOUSE (Building No. 285) HAER NO. ID-45-I (Page 7) Oil Tank Building The oil tank building is located just over the edge of the graded and leveled bench on which the Cliff Substation is situated. The building sits on a rocky outcrop to the west of the substation, above the powerhouse complex. The structure consists of a small, rectangular plan structure measuring approximately 18 feet long and 10 feet wide and composed entirely of cast-in-place concrete. It has a low-pitched gable roof that Oil tank building; view to the east from roof of 1907 powerhouse. Photo is also composed of taken May 2007. concrete. The imprints of the board forms for casting the concrete are clearly visible in the walls of the building. A small A­ frame of steel channel stock is present on top of the building, but its purpose is unclear. The east elevation of the building abuts a mortared stone retaining wall that holds back the bench on which the substation is located and cannot be described relative to its architectural details.