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FACULTY: EXPERT
DAM BIG
BY D.C. JACKSON AND DAVID P. BILLINGTON
Carrying about 14 million acre-feet of water per year, the Colorado River is not a giant among the world’s major rivers. Many streams in the East (for example, the Delaware, Hudson, and Connecticut rivers) are comparable in annual flow; the Columbia River in the Pacific Northwest is almost ten times as big. Although the Colorado River may not be large in absolute terms, it nonetheless flows through one of the driest regions of North America and offers possibilities for economic development unmatched by any other water source in the arid Southwest. . . .
The Colorado flows through or adjoins seven southwestern states (Wyoming, Colorado, Utah,
New Mexico, Arizona, Nevada, and California), but these states do not share equally in the stream’s hydrologic bounty. In terms of how Hoover/Boulder Dam came
to be built, the driving force behind the project is easily traced to both the ambitions of the U.S. Reclamation Service (later named the Bureau of Reclamation) and to political and business interests tied to southern California. Political initiatives promoting construction of the river’s first major  storage dam emanated from the southern part of California and were designed to foster
both agricultural development in the Imperial Valley and the municipal growth of greater Los Angeles. . . .
Budgeted at $177 million, the Boulder Canyon Project was billed as a multipurpose project because it would foster irrigation, provide flood control for the lower Colorado basin, supply municipal water via the Metropolitan Water District [of Southern California]’s Colorado Aqueduct, and generate hydroelectric power for the Southwest. But for all of these goals to be met, it was first necessary to build a 726-foot-high barrier across Black Canyon capable of impounding almost two years’ average flow of the Colorado River. Throughout the 1920s, Bureau of Reclamation engineers planned how this might be accomplished; in 1931, work began in earnest on what then—thanks to the September 1930 pronouncement of Interior Secretary Ray Lyman Wilbur—
was called Hoover Dam.
All activities were to be closely supervised by the Bureau of Reclamation, but construction per se was to be handled by a private contractor who had won the job by submitting a low bid in competition with other prospective builders. The largest single federal contract ever let out for bids up until that time, the building of Hoover Dam attracted the attention of some of America’s largest civil engineering contractors when advertised in January 1931.
In a story well told by Joseph Stevens in his book Building Hoover Dam: An American Adventure, the scale of the project proved so great that several prominent entrepreneurs and companies—including the Utah Construction Company, Morrison-Knudsen, the Bechtel Company, and Henry Kaiser—pooled their talents into a joint corporate initiative called Six Companies, Inc., and submitted a bid slightly less than $49 million that won them the right to build the dam proper (other aspects of the project—such as excavation of the All-American Canal, the laying of the railroad spur line into Black Canyon, and the construction of
the Hoover Dam powerhouses—were handled by other contracts).
Although many people figured into Six Companies’ success at Hoover Dam, in terms of day-to-day work within the forbidding environs of Black Canyon, none was more important than engineer Frank Crowe. After graduating from the University of Maine in 1905, Crowe joined the Reclamation Service, and, for the next twenty years, worked on a variety of Reclamation Service/Bureau of Reclamation projects. Among the most prominent of these was construction of the massive concrete curved gravity Arrowrock Dam in Idaho, built using a large cable/tramway system. In 1925, Crowe left the bureau and joined the dam-building outfit of Morrison-Knudsen, based in Boise, Idaho. When Morrison-Knudsen threw its hat in the ring with the Six Companies consortium, Crowe assumed the daunting task of coordinating all construction
work so that the company could,
as contractually obligated, complete the dam within seven years.
In basic terms, building the dam relied upon many components that proved key to its systematic and timely construction. For example, construction of a rail and road transportation system connecting Black Canyon to the outside world was vital. Also, electric power was brought in over a specially built
220-mile transmission line extending out of San Bernardino, California. But for Crowe, the most critical aspect of the project concerned excavating four 56-foot-diameter diversion tunnels (the diameter would be reduced to 50 feet after the tunnels were lined with concrete) that would eventually carry the full flow of the Colorado River around the dam site and allow excavation of the foundation. From a construction point of view, nothing of substance in terms of casting concrete in the dam or powerhouses could be accomplished prior to diversion of the river through these tunnels (in aggregate they stretched for more than 3 miles through the rock abutments of the canyon). And in a financial context, Six Companies’ contract stipulated that full diversion be accomplished by October 1, 1933, or else a $3,000 fine would be levied for every day the company failed to meet this deadline.
Thus, for both financial and practical reasons, the drilling of the diversion tunnels became of paramount importance to the company and lent an air of urgency to the start of construction in the spring of 1931. This urgency was further exacerbated by the thousands of potential workers who migrated toward Las Vegas because they saw the project as a source of desperately needed jobs. Although many arguments were made by Southern Californians during the 1920s as to why the Boulder Canyon Project should be built, the role of the project in providing employment in the midst of hard economic times was not one of them. But in the period following the dam’s approval in December 1928, the nation’s economy collapsed in the wake of the stock market crash of October 1929. By the time Six Companies commenced work in Black Canyon in the spring of 1931, the project had spawned a new objective in providing “work relief.” In this context the dam assumed a new role in the national consciousness, one that was not so much tied to the economic growth of southern California, as it was to a larger national purpose focused on overcoming adversity in difficult times—and what could be more American than that?
Although the Hoover administration remained generally opposed to federally financed relief projects designed to give an artificial boost to the economy, it proved willing to promote and encourage the job opportunities that attended construction of Hoover Dam. Thus, for a range of reasons, the bureau, Six Companies, and Crowe were anxious to get work under way at Black Canyon as quickly as possible in the spring and summer of 1931. Unfortunately for prospective laborers and their families, housing conditions near the site were abysmal at this stage of the project (construction of accommodations at the federally controlled Boulder City would not be complete for several more months), and as the heat of summer enveloped the site, fourteen workers died from heat prostration. Working conditions in the diversion tunnels proved especially dangerous, but this did not deter Six Companies from pushing ahead on this critical phase of the project.
As a result of physical hardship and apparent wage cuts invoked by Six Companies during the summer of 1931, labor unrest grew. In early August, a general strike encouraged by radical labor leaders from the Industrial Workers of the World (the IWW, or “Wobblies”) hit the project. In fending off the strike, Six Companies and the bureau shared a common interest in resisting any labor demands that threatened to impede completion of the dam. [Reclamation bureau commissioner] Elwood Mead succinctly expressed the federal government’s position by characterizing the strikers as “impossible” and proclaiming that “the present wage rate on Hoover Dam is considerably above that of the surrounding region.” Thus, once the strike was broken in mid-August by the importation of workers from Las Vegas willing to abide by the rules and wages established by Six Companies, particularly troublesome strikers were blocked by the bureau when they sought reemployment.
In even more substantive ways, the bureau supported Six Companies in terms of working conditions in the tunnels and demonstrated how federal administration of the project proved advantageous to the contractor. Specifically, this involved Six Companies’ reliance upon gasoline-powered trucks and internal combustion engines within the diversion tunnels to facilitate the rapid removal of rock blasted from the tunnel facings. Of course, operation of internal combustion engines in poorly ventilated, confined spaces offers ideal conditions for carbon monoxide poisoning. For this reason, Nevada mining law specifically forbade use of such equipment underground. During the summer of 1931, Nevada officials took legal action to prevent Crowe from using internal combustion engines inside the diversion tunnels, something he resisted because his plan for meeting the river diversion deadline required completing the tunnels as rapidly as possible; in turn, this depended upon large trucks that would drive directly into the tunnels and carry out debris on a “round the clock” basis—during January 1932, this system reached a peak when as much as 16,000 cubic yards of rock was hauled away daily.
The bureau sided with Six Companies and argued that because the dam was being built by the federal government on land that had been designated as a “federal reservation,” state laws held no power over possible construction methods. After Nevada’s state inspector of mines brought legal action to enforce state law and provide safe working conditions at the dam site, Six Companies and the bureau obtained a restraining order allowing them to proceed until a panel of federal judges in San Francisco ruled upon the merits of the case. By the time the ruling came in April 1932, much of the tunnel excavation work had been finished; regardless, the court upheld Six Companies’ and the bureau’s right to abrogate state law on this issue. . . . Beginning in early November, Crowe’s crews began dumping rock across the streambed to facilitate erection of a temporary cofferdam. As this mound of debris gradually rose, it elevated the height of the river. On November 14, 1932—only days after President Hoover had failed in his effort to be reelected—water began spilling into the diversion tunnels on the Arizona side of the construction site. With this, the mighty Colorado River had been “tamed” and foundation excavation became possible. The building of the dam then entered a new phase.
The diversion of the river allowed for site preparation to begin in earnest. . . . Excavation into the bottom of Black Canyon commenced in November 1932, and by early June 1933, Six Companies was ready to start pouring concrete.
Compared to the uncertainties involved in drilling the diversion tunnels, the casting of concrete represented a much more predictable and controllable task—although it required a complicated and potentially dangerous coordination of men, machines, and huge buckets of wet concrete. Preceding the first casting of concrete on June 6, 1933, the bureau oversaw erection of an elaborate concrete-making plant on the Nevada side of the canyon that mixed water, cement, and locally obtained aggregates (i.e., sand and gravel). From the plant, large batches of freshly mixed concrete (carried in buckets with a capacity
of eight cubic yards) were delivered to various parts of the ever-rising dam via a cableway strung across
the canyon.
Because the dam could not be formed in one continuous pour, the design called for the concrete to be placed in an assemblage of blocks to be cast independently and allowed to harden before the pouring of adjoining blocks. To speed cooling of the massive structure—something necessary because of the tremendous amount of heat released by the concrete as it hardened—an extensive system of one-inch-diameter cooling pipes (measuring about 592 miles in total) was embedded in the dam. These pipes, representing a technology that the bureau had experimented with during the construction of Owyhee Dam in Oregon a few years earlier, contained refrigerated water. This cool liquid extracted excess heat from the hardening concrete (resulting from what engineers term “heat of hydration”) and prevented the creation of potentially dangerous temperature cracks within the interior of the dam. Water passed through the cooling coil pipes at a rate of at least three gallons per minute; at the completion of construction, the bureau estimated that about 159 billion BTU (British Thermal Units) of energy had been extracted out of the dam by the cooling system.
After the first several weeks of casting concrete, the construction process became regularized and relatively routine, although it never became simple. The growing skill of Crowe’s workers and the efficiency of the concrete delivery system becomes apparent in reviewing the quantities of concrete placed on a monthly basis: in June 1933, 25,000 cubic yards of concrete were placed; two months later in August, the amount reached 149,000 cubic yards; and in March 1934, it reached a peak of over 262,000 cubic yards—the equivalent of 1,100 buckets per day or about one every seventy-eight seconds. By December 1934, more than 3 million cubic yards of concrete had been cast in the dam; in early February 1935, the structure “topped out” with delivery of the last batch. At this time, the bureau dropped the massive bulkhead gates placed across the openings of the diversion tunnels, and aside from flow released to meet the needs of downstream irrigators, the Colorado River was blocked in its journey toward the Pacific. Gradually the reservoir behind the dam began to rise, and the once-free-flowing stream experienced a dramatic transformation.
While work building the dam proper proceeded through 1934 and into 1935, other tasks such as building the powerhouses, the outlet towers, the spillways, and the tunnels that served them continued apace. A year later, in March 1936, the dam and powerhouses were officially declared to be complete, and—as Six Companies officially left Black Canyon—the bureau assumed responsibility for installing the initial set of hydroelectric turbine/generator units in the powerhouses.
On October 7, 1936, water passed through one of the recently completed main turbine/generator units, and two days later, hydroelectric power first surged out of Black Canyon into southern California via a transmission line built by the City of Los Angeles.
Lafayette faculty are experts in their fields. Interests among the 198 members range across the full spectrum of humanistic,
scientific, and technical knowledge. Lafayette encourages and supports faculty research and scholarship in the belief that such professional involvement extends the individual faculty member’s intellectual resources, strengthens and complements teaching effectiveness, facilitates student/faculty research, and contributes to the scholarly and professional communities outside the College. “Faculty: Expert” highlights a faculty member’s research.
Excerpted from Big Dams of the New Deal Era: A Confluence of Engineering and Politics by David P. Billington and Donald C. Jackson © 2006 by the University of Oklahoma Press, Norman, publishing division of the university.
All rights reserved. Reprinted with permission.
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Frank Crowe, the Six Companies engineer
responsible for construction of Hoover Dam.
A promotional map (circa 1935) distributed by the Metropolitan Water District of Southern California, showing the relationship of the “Boulder Canyon Dam” to the suburban/urban area surrounding Los Angeles; the map also highlights the route
of the Colorado Aqueduct that—using hydroelectric power generated at the dam
to operate large pumps—will deliver water to the region. Courtesy Metropolitan
Water District of Southern California.
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