Hoover Dam, Henderson-Mead Transmission Line 2, Spanning Colorado River at Route 93, Boulder City

Source document Quoted word for word from HAER NV-27-Y. Not written, edited or summarised by this site.

U.S. Highway 93 Vicinity of Boulder City Clark County Nevada USGS Boulder City, Nevada-Arizona 7.5 Minute Provisional UTM Coordinates: 1 (start) 1 (middle) 1 (end) Date of Construction: Engineer: U.S. Bureau of Reclamation Builder: U.S. Bureau of Reclamation U.S. Highway 93 Vicinity of Boulder City Clark County Nevada USGS Boulder City, Nevada-Arizona 7.5 Minute Provisional UTM Coordinates: (start) l (middle) l (end) Statement of

Source document Quoted word for word from HAER NV-27-Y. Not written, edited or summarised by this site.

Previously known as a segment of the Davis-Hoover and the Hoover-Mead Transmission Lines, the documented segment of the Henderson-Mead Transmission Line 2 was constructed to connect the generating and transmission systems of the Boulder Canyon Project at Hoover Dam with those of the Davis Dam (eventually the Parker-Davis Project). Construction and operation of the Davis-Hoover line helped the Bureau of Reclamation ensure maxim use of water power in the Colorado River. Report Prepared by: Associated Cultural Resource Experts (ACRE) Sangre de Cristo Road, STE 202 Littleton, CO Date: April HISTORIC AMERICAN ENGINEERNG RECORD HOOVER DAM, HENDERSON-MEAD TRANSMISSION LINE 2 HAER NO.

(Page 2) The Henderson-Mead Transmission Line 2 extends from a substation in Henderson, Nevada southeastward to near Hoover Dam, then westward to the Boulder City Tap Substation, and then southwestward to Mead Substation. The portion of the line from Henderson to near Hoover Dam was constructed as the Hoover-Basic Magnesium North line, which provided electricity for a major WWII magnesium plant. The portion of the line from near Hoover Dam to the Boulder City Tap Substation is a recent installation on towers of the Los Angeles BPL Transmission Line No. 2 (HAER which was one of the original high-voltage transmission lines from Hoover Dam to California.

The segment of the Henderson-Mead Transmission Line 2 from Boulder City Tap Substation to Mead Substation (the segment documented here) was part of the Davis-Hoover Transmission Line, which was constructed to connect the generating and transmission systems of the Boulder Canyon Project at Hoover Dam with those of the Davis Dam (eventually the Parker- Davis Project). Construction and operation of the Davis-Hoover Transmission Line allowed the Bureau of Reclamation to ensure maxim use of water power in the Colorado River. Description: This is the northernmost approximately 3.5 miles of the transmission line originally called the Davis-Hoover and later the Hoover-Mead transmission line.

The portion documented is from the Basic/Boulder City Tap Substation southwestward across open desert landscape to a tie line to Mead Substation. The line continues southwest to a switchyard near Davis Dam. The transmission line is comprised of single-circuit steel towers of narrow-waist type, with the base rotated 45 degrees to the direction of the line. Tower bases are 32-feet square, and the towers are 109 feet 2 inches from base to the overhead ground wires at the towers' highest points. From 65- foot-long cross-members, three conductors are suspended under insulator strings composed of 24 IO-inch porcelain insulators.

History: The recorded resources were part of the Davis-Hoover Transmission Line, which was constructed in to connect the generating and transmission systems of the Boulder Canyon Project at Hoover Dam with those of Davis Dam (and eventually the Parker-Davis Project). The Davis- Hoover Transmission Line extended from a switchyard at Davis Dam to the Basic Tap Substation (know called the Boulder City Tap Substation), where the Davis-Hoover Transmission Line tapped into Hoover-Basic South Transmission Line, a line that had been built in primarily to carry power to the Basic Magnesium, Inc. production plant in Henderson, Nevada. In the late or early switching and control of the Davis-Hoover line was sectionalized into the Hoover-Mead Transmission Line (also called the Hoover-Mead No.

1) from the Arizona- Nevada Switchyard at Hoover Dam, through the Basic/Boulder City Tap Substation, to Mead Substation, and the Davis-Mead Transmission Line between the Mead and Davis Dam switchyards. The current Hoover-Mead/Hoover Mead No. 1 arrangement therefore includes a portion of the original Hoover-Basic South Transmission Line.

Source document Quoted word for word from HAER NV-27-Y. Not written, edited or summarised by this site.

This documentation of features of Hoover Dam and associated structures was accomplished by Associated Cultural Resource Experts (ACRE). ACRE completed documentation of21 features in HOOVER DAM, HENDERSON-MEAD TRANSMISSION LINE 2 HAER NO.

(Page 3) October Documentation of four linear features was extended and an additional 3 features were newly documented in February Both phases of documentation were conducted as part of the historical/engineering recordation of Hoover Dam-prepared for the Department of Energy, Western Area Power Administration; Bureau of Reclamation; and Federal Highway Administration-that includes a narrative for the Addendum to Hoover Dam and individual documentation of 25 features located at the Hoover Dam facility, photo documentation, and documentation of existing historic photographs and site plans. The recordation conforms to the standards of the Historic American Engineering Record, U.S. Department of the Interior.

Other reports in the HAER collection completed for these projects are a narrative for the Addendum to Hoover Dam and 24 short forms for individual structures: Hoover Dam, Los Angeles Switchyard (NV-27-A); Hoover Dam, Southern Sierras/CEP/Southern California Edison Switchyard Hoover Dam, Metropolitan Water District Switchyard Hoover Dam, State of Nevada Switchyard Hoover Dam, Southern California Edison Switchyard (NV-27-E); Hoover Dam, Arizona-Nevada Switchyard Hoover Dam, Static Towers and Lines Hoover Dam, Los Angeles Relay Control Building Hoover Dam, Switchyard Fire House Hoover Dam, Promontory Water Tank Hoover Dam, Control Cable Hoist House Hoover Dam, Transformer Circuits Hoover Dam, Los Angeles BPL Lines 1-3 Hoover Dam, Southern California Edison North and South Lines Hoover Dam, Hoover-Basic Magnesium North and South Lines Hoover Dam, Metropolitan Water District Line 1 Hoover Dam, United States Construction Railroad Hoover Dam, U.S.

Highway 93 Nevada Segment Hoover Dam, Lower Portal Access Road Hoover Dam, Kingman Switchyard Hoover Dam, U.S. Highway 93 Arizona Segment (NV-27-U); Hoover Dam, Explosives Magazines Hoover Dam, Nevada Downstream Waste Tailings and Hoover Dam, Nevada Spoils Tunnel Hoover Dam, Henderson-Mead Transmission Line 2

Source document Quoted word for word from HAER NV-27-Y. Not written, edited or summarised by this site.

This documentation was prepared for three federal agencies: U.S. Department of Transportation, Federal Highway Administration (FHWA), Central Federal Lands Highway Division, Lakewood, CO; U.S. Department of Energy, Western Area Power Administration (Western), Desert Southwest Customer Support Region, Phoenix, AZ; and U.S. Department of Interior, Bureau of Reclamation (Reclamation), Lower Colorado Region, Boulder City, NV. This documentation records certain transportation and electrical features associated with Hoover Dam before planned removal or alteration of some structures. FHWA plans to construct a bridge over the Black Canyon of the Colorado River about downstream from Hoover Dam. The Hoover Dam Bypass Project would include realignment of U.S.

Highway 93 on the Nevada and Arizona sides of Black Canyon. The project would include demolition, relocation, or substantial visual impact to a segment of U.S. Highway 93 on the Nevada approach to Hoover Dam, a segment of a former alignment of U.S. Highway 93 in Arizona, electrical transformer circuits in Arizona and Nevada, two electrical switchyards, a segment of the grade of the U.S. Construction Railroad, a stone gate structure for a dam construction and operations road, and six historic transmission lines. This documentation also records certain structures not directly affected by FHWA's Hoover Dam Bypass Project. Electrical transmission facilities at Hoover Dam are administered by Western, but these facilities are within a federal reservation administered by Reclamation.

Documentation of electrical structures is intended to partially fulfill responsibilities of Western and Reclamation under Section 110 of the National Historic Preservation Act (As amended). Some electrical structures addressed by Western and Reclamation would be directly affected by FHWA's Hoover Dam Bypass Project, and all structures addressed by Western and Reclamation are functionally related and geographically near structures addressed by FHWA. HOOVER DAM, HENDERSON-MEAD TRANSMISSION LINE 2 HAER NO. (Page 4) Project Manager and historian for the recordation was Kurt P. Schweigert of Associated Cultural Resource Experts. The photographers were Deborah Dobson-Brown and Douglas M. Edwards of Associated Cultural Resource Experts.

This documentation was prepared on the basis of research conducted at Reclamation archives in Denver, CO, and Boulder City, NV; Western archives and files in Denver and Phoenix, AZ; the National Archives and Records Administration in Denver; libraries of the University of Nevada-Las Vegas; and the Western History Collection of the Denver Public Library. This documentation includes information contained in survey reports for the Hoover Dam Bypass Project Environmental Impact Statement, an evaluation of the Western switchyards at Hoover Dam, an evaluation of the Hoover Dam construction railroads, a National Register nomination for Hoover Dam, and other documents.

Source document Quoted word for word from HAER NV-27-Y. Not written, edited or summarised by this site.

Kurt P. Schweigert, Associated Cultural Resource Experts, HOOVER DAM, HENDERSON-MEAD TRANSMISSION LINE 2 HAER NO. (Page 5) HOOVER DAM, HENDERSON-MEAD TRANSMISSION LINE 2 HAER NO. (Page 6) Cl) bl 1 0 ,G u ADDENDUM TO: HAER HOOVER DAM, HENDERSON-MEAD TRANSMISSION LINE 2 HAER (Boulder Dam, Hoover-Mead Transmission Line) (Boulder Canyon Dam, Davis-Hoover Transmission Line) Spanning Colorado River at Route 93 Boulder City vicinity Clark County Nevada PHOTOGRAPHS HISTORIC AMERICAN ENGINEERING RECORD PACIFIC WEST REGIONAL OFFICE National Park Service U.S. Department of the Interior Jackson Street, Suite 700 Oakland, CA