Cooling mass concrete: Owyhee, Hoover, and building large dams

During the first half of the twentieth century, the US Bureau of Reclamation's engineers designed increasingly ambitious dams, culminating in the early 1930s with the construction of Boulder Dam (now known as Hoover Dam) on the Colorado River. Such projects required advancing the state of materials science, especially in understanding the behaviour of mass concrete as it hardened, leading in turn to new methods for pouring mass concrete. One requirement, when pouring a mass as large as Boulder Dam, was to remove the tremendous amount of heat generated by hydration, the chemical reaction that occurs as concrete cures, in order to keep the volumetric change of the mass to a minimum and thereby avoid undue cracking. Reclamation engineers developed a method to cool Boulder Dam's concrete mechanically, which they tested during the construction of Owyhee Dam in Oregon, which preceded Boulder Dam as the world's highest dam. This relationship between the construction of Owyhee Dam and Boulder Dam demonstrates the application of scientific research and the high level of complexity that engineers were able to manage well before the formal advent of systems engineering in the second half of the twentieth century.