FOOTNOTES:
[9] The sill of the Chaffey gate proved to be too high for low stages of water, and a canal, at a lower level, was cut around the structure and closed every year with a brush-and-earth dam before the approach of the summer flood. G. K.
[10] Mr. Randolph was a distinguished civil engineer and railroad manager, who had been, at one time, superintendent of the Tucson division of the Southern Pacific under Mr. C. P. Huntington. After the latter’s death, he went to Los Angeles, where he built and managed Mr. H. E. Huntington’s interurban system of electric railways and where he made the acquaintance of Mr. Harriman. Finding that his health would not permit him to live in the climate of Los Angeles, he returned in 1904 to Arizona, where he was appointed president of the Arizona Eastern Railroad Company and the Southern Pacific Railroad Company of Mexico—Harriman lines. Mr. Randolph, at that time, was regarded as one of the ablest civil engineers in the United States, and he had already had much experience in dealing with river-control problems in the South. He was also one of Mr. Harriman’s most trusted counsellors, and it was upon his recommendation that the Southern Pacific Company’s lines were extended into Mexico.
[11] Mr. Cory was a talented civil engineer who had left his professorial chair in the engineering department of the University of Cincinnati to enter the service of the Southern Pacific Railroad system. Just prior to this time—in May 1905—he had been appointed assistant to President Randolph, with headquarters at Tucson.
THE SAVING OF THE VALLEY
When the Southern Pacific engineers undertook to avert the peril that menaced the Imperial Valley in the summer of 1906, they found little in recorded history to help or guide them. Inundations, of course, had often occurred before, on the Mississippi River and its tributaries, in the valley of “China’s Sorrow,” and in many other parts of the world; but these floods were merely overflows on a relatively flat surface. The cosmical plunge of a great river into the dried-up basin of an ancient sea was an unprecedented phenomenon, and one which raised engineering problems that were wholly new. Nobody had ever before tried to control a rush of 360,000,000 cubic feet of water per hour, down a four-hundred-foot slope of easily eroded silt, into a basin big enough to hold Long Island Sound. There was nothing in the past experience of the world that could suggest a practicable method of dealing with such conditions. Neither was much help to be obtained from the advice of hydraulic experts. Of the forty or fifty eminent engineers who visited the Colorado delta in 1905 and 1906, hardly any two agreed upon a definite plan of defensive work, while almost everyone found something objectionable in the measures suggested by others. All admitted, however, that “the situation was a desperate one;” that it was “without engineering parallel;” and that “there seemed to be only a fighting chance of controlling the river.”
Mr. Harriman, who believed and who once said that “nothing is impossible,” never doubted that the control of the Colorado River was within human power and human resources. In building the Lucin cut-off across the Great Salt Lake of Utah he had successfully carried through one “impossible” enterprise, and he did not hesitate to undertake another. Inspired by his invincible courage, President Randolph and his engineers set about their herculean task.
In preparing for a fifth attempt to bring the Colorado under control, they determined to modify the plan of operations previously followed by substituting rock for the materials that had before been used in the construction of dams. Practical experience had shown that piling, brush, sandbags and earth could not be made to support the pressure of the river in full flood, while a series of rock-fill barrier dams, of sufficient width and height, might be strong enough to stand even a flood discharge of 115,000 cubic feet of water per second. In making this change of plan, Mr. Randolph acted on his own judgment and in direct opposition to the views and advice of experts who were acquainted with the situation. Almost all of the engineers who had visited the break, including many of national and international reputation, regarded a rock-fill barrier dam as wholly unworthy of consideration, for at least two reasons. First, the rock would probably sink into the soft silt bottom, and keep on going down indefinitely. It might perhaps be supported by a strong brush-mattress foundation, but even then, the mattress would be likely to break under the weight of the load and thus fail to answer its purpose. Second, the water going over a rock-fill dam, while it was in course of construction, would almost certainly wash away some one rock at the top. This, by increasing the overflow at that point, would dislodge more rocks, and finally create a breach that could not be closed. President Randolph who had used brush-mattresses and rock-fill dams on the Tombigbee River in Alabama many years before, fully considered these objections but did not find them convincing and steadfastly adhered to his own plan.
The preparations made for the summer’s work were far more thorough and comprehensive than any that had ever been made before. Realizing the importance of adequate transportation, President Randolph and his engineers immediately began the construction of a branch railroad from the main line of the Southern Pacific to the scene of operations at the crevasse, with ample sidings and terminal facilities at both ends. Then they borrowed from the Union Pacific three hundred of the mammoth side-dump cars known as “battleships,” which had been used in the construction of the Lucin cut-off, and which had a carrying capacity of fifty or sixty tons each. The California Development Company had three light-draught steamers and a number of barges that could be used on the river, and the Southern Pacific Company furnished complete work-trains, from time to time, until a maximum of ten was reached. The next requisite was material for levees and dams, and this they secured by drawing upon all the rock quarries within a radius of four hundred miles, and by opening a new one, with a face of six hundred feet and a height of forty feet, on the granite ledge at Andrade near the concrete head-gate. Clay they obtained from a deposit just north of the Mexican boundary, and gravel they hauled from the Southern Pacific Company’s “Mammoth Gravel Pit,” which was situated on the main line about forty miles west of the crevasse spur. From Los Angeles they brought 1100 ninety-foot piles, 19,000 feet of heavy timbers for railway trestles, and forty miles of steel cable to be used in the weaving of brush-mattresses. The Southern Pacific Company furnished pile-drivers, steam shovels for the granite quarry and gravel pit, several carloads of repair parts, and a large quantity of stores and materials of various kinds. It also detailed for service on the spur railroad and at the crevasse as many engineers, mechanics and skilled workmen as were needed. The chief reason, Mr. Cory says, “for having the railroad company supply so great a quantity of labor, equipment and supplies, was that it afforded an opportunity to assemble quickly a thoroughly organized and efficient force of men; the advantage of obtaining material and supplies through the purchasing department of the Harriman systems; immediate shipment of repair parts not kept on hand; and the ability to increase or decrease rapidly the force and equipment without confusion.”
The requisite most difficult to obtain, in sufficient amount, was unskilled labor. An attempt was made to get five hundred peons from central Mexico; but it did not succeed, and Mr. Cory was finally compelled to mobilize all the Indian tribes in that part of the Southwest—Pimas, Papagoes, Maricopas and Yumas from Arizona and Cocopahs and Diegueños from Mexico. These Indians fraternized and got along together amicably, and constituted with their families a separate camp of about two thousand people. The rest of the laborers were Mexicans from the vicinity, and drifting adventurers from all parts of the United States who were attracted to the place by the novelty of the work and the publicity given to it in the newspapers. Arrangements were made with the Mexican authorities to put the whole region under martial law and to send a force of rurales with a military commandant to police the camps.