Initial reconnaissance for a transmission line route was started in 1922. Years of careful consideration went into selecting the route, which took into consideration important factors including greatest public good, reliability of transmission, minimum distance between Hoover Power Plant and Receiving Station B in South Los Angeles, access for construction equipment, and protection from flood waters.
To select the most desirable route, a wide area was surveyed, reaching to the Colorado River on the east and from Death Valley south to a line extending from San Gorgonio Pass to Parker. Surveys were completed by airplane, automobile, and foot until the possible route had been narrowed down to a four-mile-wide strip. After locating the line, profiles were made, tower locations were spotted and staked out, and templates were checked before the tower steel was erected.
Montebello, Baldwin Park & San Dimas Sections
To support construction of the last 40.8 miles of Boulder Transmission Line into Los Angeles, three headquarters facilities were built by LADWP. Each headquarters location included a warehouse, hospital, office, gas station, auto shop, blacksmith shop, grease rack, and wash rack. Due to the proximity to Los Angeles, no camps or bunkhouses were built to house employees on site.
Double circuit towers were considered practical in the transmission sections closer to Los Angeles because of the minimal danger from lightning and the expense of rights-of-way. They were built three times heavier than the single circuit towers, as they carry the weight of two circuits instead of one. At 144 feet in height, these double circuit towers were just 6 feet shorter than the height limit allowed for buildings in the City of Los Angeles at that time.
The last Boulder Transmission Line tower was completed July 22, 1936, in the Baldwin Park Section, resulting in a total of 2,695 towers along the 266-mile route. Cable stringing operations were completed in August 1936, also in the Baldwin Park Section, which made for a final total of 1,596 miles of hollow copper conductor strung.
Upland
Double Circuit Towers Transition to Two Parallel Single Circuit Towers
In the hills above Upland, the double circuit Boulder Transmission Lines transition to two parallel single circuit towers for the remaining 225-miles to Hoover Dam. This location in Upland is also the end point for the approximately 15-foot-wide dirt transmission patrol road that runs all the way to Boulder City.
Cozy Dell Camp
Located in the Cajon Pass, Cozy Dell was the construction camp located closest to Los Angeles and was placed into service in October 1933. Located a short distance below the former Santa Fe Railroad Cajon Station, 300 LADWP workers were assigned to this location. While the other six camps were powered by butane, due to its proximity to urban life, the Cozy Dell was able to be powered electrically and utilized a state-of-the-art electric stove.
Cozy Dell Transmission Construction Section
The Cozy Dell Section was the most difficult portion of the Boulder Transmission Line to build. It includes extremely rugged terrain and topography, with deep ravines and thickly matted underbrush. Road construction was difficult, and in accordance with Forest Service regulations at the time, the maximum grade could not exceed 10 percent. Several miles of transmission road had to be blasted out of the mountain, making hand labor mandatory. Other challenges included delays in gaining permission from what was then known as the Federal Power Commission for the 14-mile right-of-way through the San Bernardino National Forest. Sudden rainstorms, blistering heat, and numbing cold added additional challenges to construction activities. Due to all these challenges and associated delays, Cozy Dell was the last single circuit tower section completed, occurred on October 24, 1935.
Adelanto
Adelanto Converter Station
The Adelanto Converter Station was originally constructed in early 1983 to facilitate the arrival power from the Intermountain Power Project in Delta, Utah. This power arrives via the dedicated 488-mile high voltage direct current (HVDC) transmission line, and it is converted at this facility to alternating current for the final journey to Los Angeles. While the converter station and HVDC transmission line are operated by LADWP, this facility that is located within the larger Adelanto property is owned by the Intermountain Power Agency, a subdivision of Utah state government.
LADWP Adelanto Solar
Completed in 2012, this 10-megawatt utility-scale solar array was built on a 42-acre site within the LADWP Adelanto Switching Station property. LADWP owns and operates the Adelanto Solar system. The project created 150 clean energy jobs between LADWP and the contractors involved in this effort.
Budgeted at $48 million, the Adelanto Solar Project benefitted from financing by federal Qualified Energy Conservation Bonds. The bonds offered through the American Recovery and Reinvestment Act and resulted in significant savings for LADWP ratepayers through subsidized loan interest costs.
Victorville
Former Victorville Employee Housing Compound
Located on Historic Route 66, this facility on a 2.6-acre site was completed in 1937 to serve as a LADWP employee housing compound for the operators of Victorville Switching Station, personnel who patrolled a roughly 50-mile section of the Boulder Transmission Line, and their families. Designed around a U-shaped street, there were originally six homes grouped around the central park where shade trees were planted to help to minimize the high summer temperatures. To add an element of urban ambiance, City of Los Angeles-style streetlights were installed in the central park and in front of the homes.
The six former residences were designed by former LADWP architect Jacques “Jack” de Forest Griffin, who designed the several dozen employee homes in Boulder City, along with five additional residences and a guest house at Silver Lake Switching Station. Using plans identical to the homes that will be seen later in Boulder City, these residences were designed in Monterey style and built with tile roofs, stucco walls, and pergolas to help minimize the high summer temperatures. The walls and ceilings of these homes were insulated but unlike the residences at Silver Lake Switching Station where temperatures were the hottest, air-conditioning systems were not originally included in Victorville. While the six homes were demolished in the late 1980s, the remaining central park, shade trees, streetlights, and large tile roof garage building are original to this property.
Victorville Transmission Patrol Headquarters
Today, this facility continues to serve as the Victorville Transmission Patrol Headquarters, but LADWP employees no longer live on site. This location also serves as the home base for LADWP Victorville Telecom employees who maintain microwave sites and communications facilities for several transmission lines in the area. The original garage building is staffed by LADWP mechanics who maintain fleet vehicles.
Victorville 287.5 kV Switching Station
This 10-acre site is home to the original 287.5 kV Victorville Switching Station, which was designed as a key component of the Boulder Transmission System. Completed in October 1936 just before Hoover Power arrived in Los Angeles, Victorville and the identical Silver Lake Switching Station were constructed at a cost of $1 million each and were state-of-the-art for the time. Early LADWP studies showed that sections of the transmission line that experienced faults at full voltage had to be switched every 90 miles and more rapidly than available technology allowed. These stations were designed to fulfil this reliability need and each contained four of the largest and fastest operating oil circuit breakers ever built. In the case of transmission line trouble, the circuit breakers would isolate the affected line section and transfer the power load to the remaining circuit in one-tenth of a second.
The Boulder Transmission System was designed with an advanced lighting protection system, which included 150-foot-high steel diverter towers at the two switching stations. Victorville and Silver Lake each had six towers to carry the associated counterpoise wires over the station.
Victorville 500 kV Switching Station
Construction on this 20.5-acre 500 kV switchyard commenced on February 9, 1972. This facility was originally built as a transmission line interconnection between Victorville Switching Station and the Southern California Edison Lugo Switching Station in Hesperia, California. When Boulder Line III was upgraded to 500 kV in 1970, it was initially reconfigured to bypass Victorville Switching Station entirely, operating as a straight 238-mile shot from Boulder City to Receiving Station E in North Hollywood, without any switching stations in between. The 500 kV Victorville Switching Station yard was later interconnected with both the original 287.5 kV switchyard across the street, as well as the Boulder III and Boulder II transmission lines when the latter line was upgraded to 500 kV in 1980.
Victorville Camp
Located approximately 12 miles east of Victorville, this was largest construction camp with 34 bunk houses. Work to build this camp started in October 1933, and transmission tower erection in this section commenced in June 1934. The concrete for the transmission tower footings between Victorville and Silver Lake was usually poured at night because of the high temperatures, which also required that the crews who laid out the steel take breaks every 15 minutes. Despite the conditions, the 13-man assembly crews were eventually able to erect each transmission tower in five and a half hours.
All seven LADWP construction camps hosted various activities and competitions for crews in their downtime. The Victorville Camp baseball team were undisputed champions in the Victor Valley night softball league against the Portland Cement team and moved on to the playoffs with the champions of other desert leagues.
Barstow
Construction plans and specifications for the Barstow Transmission Patrol Headquarters were prepared by the LADWP Design and Construction Division for bids in early 1941. Plans called for three double residences, a dormitory, along with a combination office, garage, and storeroom. LADWP architect Jacques “Jack” de Forest Griffin assisted with structural details. Personnel were responsible for a portion of the transmission line section between Victorville and Silver Lake. When regular LADWP helicopter patrols were implemented in the early 1950s, this facility was closed.
Yermo
In Yermo, all three Boulder Transmission Lines cross over Interstate 15. The fourth line is the 488-mile High Voltage Direct Current (HVDC) transmission line that originates at the Intermountain Power Project in Delta, Utah. This HVDC transmission line is also operated and maintained by LADWP. This HVDC line begins to parallel with the Boulder Transmission Line right-of-way as it departs from the outskirts of Boulder City. After traveling approximately 160 miles in parallel, it splits off towards Adelanto as the Boulder Transmission Lines approach Victorville.
Yermo Field Office and General Headquarters
In summer 1933, LADWP initially established its Yermo Field Office and General Headquarters in a corrugated tin structure that was formerly the N&N Café, along with several repurposed buildings that included the former Yermo Auto Court and “Wilson’s Garage.” During construction of the Boulder Transmission System, all clerical work was cleared through this facility, and it provided offices and lodging for the LADWP general construction superintendents, division superintendents, and chief clerks. In December 1933, LADWP completed construction of proper facilities at a shaded location on the main line of the Union Pacific Railway, next to the train depot. This purpose-built site contained a general office building, radio and teletype station, warehouse, machine shop, fleet maintenance garage, and the necessary employee living quarters. While there were 12 bunk houses on site, this was not used as a construction camp. During construction of the third Boulder Transmission Line, the Yermo facility was placed back into operation to support field work.
Harvard
Harvard Camp
Located east of Harvard, this camp contained 17 bunk houses and housed 200 workers. It was the first camp to be constructed and first camp to close. On September 15, 1933, Los Angeles Mayor Frank L. Shaw visited Harvard Camp for lunch as part of a delegation inspection tour of the Boulder Transmission Line and Hoover Dam construction. Mayor Shaw was one of the staunchest supporters of public power and municipal ownership.
A friendly rivalry developed between the camps to see which could finish construction work the fastest. In spring 1934, Harvard Camp set the unofficial record of pouring 48 concrete footings for towers in a single shift.
Baker
Baker Survey Headquarters
During the initial transmission right-of-way surveys in 1933, headquarters were established in Baker to support the fourteen LADWP survey parties put into the field in to blaze a path for the construction crews.
Silver Lake
Silver Lake Camp
Located approximately 9.5 miles north of Baker on a dry lakebed, construction of Silver Lake Camp was completed in July 1933. Construction materials for the transmission towers and switching station were delivered to this location on a Union Pacific Railway spur. Silver Lake was the last camp to be dismantled, as it was used to house workers who were finishing construction on the Silver Lake Switching Station Control House.
Silver Lake Switching Station
Located north of Baker and 90.8 transmission line miles from Victorville, and virtually identical in appearance, the Silver Lake Switching Station served as the second circuit breaker on the Boulder Transmission System. By the time Boulder Line III was upgraded to 500 kV in 1970, transmission technology had advanced to the point that Silver Lake was no longer needed. In December 1970, Silver Lake was bypassed and removed from LADWP’s system.
Silver Lake Housing Compound and Transmission Patrol Headquarters
To house the Silver Lake Switching Station operators and transmission line patrol staff, an employee housing compound was completed in 1937 adjacent to the switchyard. It contained five residences and a guest house, designed in Monterey style by LADWP architect Jacques “Jack” de Forest Griffin. These homes were identical to those built in Victorville and Boulder City. In the initial years of operation, butane was trucked in from Los Angeles for heating and to fuel a Kohler generator that powered the homes. It wasn’t until Boulder Line III came online in 1940 that LADWP eventually brought in a transformer and tapped the transmission line to provide an electrical connection to the Silver Lake facilities.
Kingston Valley
Kingston Camp
This camp was located at the base of Shadow Mountain, approximately 8 miles north of Baker. This location was considered the most picturesque of the seven camps. Construction of Kingston Camp was completed in July 1933.
The first tower for the Boulder Transmission System was erected one mile east of the camp on December 19, 1933, even before the right-of-way surveys were completed in January 1934.
On March 18, 1935, cable stringing operations commenced on the transmission line at four construction camps: Harvard, Silver Lake, Kingston and Jean. Fifty men comprised each of the four crews that operated the four stringing machines. Each crew averaged three one-mile strands per working day.
State Line
Jean Camp
Located several miles south of the town of Jean, Nevada, this construction camp was located next to a former ghost town known as Roach, in the vicinity of present-day Primm, Nevada. Jean Camp was the second largest construction camp with 25 bunk houses and set the speed record for the installation of transmission tower line.
Jean Transmission Patrol Headquarters
Upon completion of construction and before the transmission line was energized, the former Jean Camp kitchen and mess hall buildings were altered to become cottages to house three Jean Transmission Patrol employees and their families. Since temperature variations in the Jean section were extreme, the three cottages were well insulated with Celotex and spun glass pads, which were laid on the old flooring and covered with new flooring. The hot water heating system was placed back into service, and a leftover butane system was utilized for heating and cooking. Light was supplied by two automatic electric generators, powered by gasoline engines. In the old kitchen building, a huge leftover ice box was used as a community refrigerator.
Boulder City
Boulder Camp
In 1933, LADWP established its first major presence in Boulder City by assembling a temporary construction camp on the outskirts of town to build the Boulder Transmission Line. It contained 20 bunk houses and was located on the site of what would later become the Boulder City Cemetery.
Boulder City Historic District
In 1983, Boulder City was listed on the National Register of Historic Places as the Boulder City Historic District. The district encompasses 514 buildings and structures, which were primarily constructed between 1931 and 1942. These dates correspond to the initial construction and operations phase of Boulder City’s history.
Boulder Dam Hotel & Museum
Located at 1305 Arizona Street and designed by architect L. Henry Smith, Boulder Dam Hotel was completed in December 1933 by contractor Paul Webb. This Southern Dutch Colonial style hotel was built during the construction of Hoover Dam to accommodate a growing tourist industry and provide lodging for famous and wealthy guests. Notable hotel guests included James Cagney, Bette Davis, Henry Fonda, Howard Hughes, and Will Rogers.
On April 15, 1939, Crown Prince Frederik and Crown Princess Ingrid of Denmark dropped by Boulder Dam Hotel for a brief visit in conjunction with their Hoover Dam tour and lunch hosted at LADWP Boulder Lodge. On May 13, 1939, their cousins Crown Prince Olav and Crown Princess Martha of Norway attended a lavish luncheon on the East Terrace of the hotel. Among the invited special guests were United States Senator Pat McCarran and LADWP Assistant Superintendent of Generation for Boulder Division, Ernest P. Bryant.
This building continues to be operated as a 20-room hotel, restaurant, and museum. A large portion of the first floor that originally contained hotel rooms now serves as the Boulder City-Hoover Dam Museum.