THE RUNAWAY RIVER

The most serious problem with which engineers have to deal in the irrigation of arid land from a turbid river is the getting rid of silt, and this problem is a particularly difficult one in the Imperial Valley, owing to the immense amount of sediment that the irrigating water contains. The Colorado River, until after it passes the Grand Cañon, is almost everywhere a swift, turbulent stream, with great eroding capacity. AsMr.E. C. LaRue has said, in a brief but graphic description of it,

“When the snows melt in the Rocky and Wind River Mountains, a million cascade brooks unite to form a thousand torrent creeks; a thousand torrent creeks unite to form half a hundred rivers beset with cataracts; half a hundred roaring rivers unite to form the Colorado, which flows, a mad, turbid stream, into the Gulf of California.” (“Colorado River and Its Utilization,” a Geological Survey report, Government Printing Office, Washington 1916.)

Such a river, naturally, dissolves the earth and gnaws the rocks over which it tears its way, and takes up millions of tons of solid matter, in the shape of gravel, sand and finely pulverized soil. This great volume of sediment, whenfinally dropped, not only tends to change the river’s course by creating bars at or near its mouth, but gradually fills up the irrigating ditches and canals and thus lessens their carrying capacity. A single day’s supply of water for the Imperial Valley contains silt enough to make a levee twenty feet high, twenty feet wide, and one mile long. (Imperial Valley Press, July 25 1916). If this silt is not dredged out, sluiced out, or collected in a settling basin, it eventually raises the beds of the canals, fills the ditches, and chokes up the whole irrigation system.

The managers of the California DevelopmentCo.had difficulty, almost from the first, in keeping their waterways open. As more and more land was brought into cultivation, more and more water was required, while the silting up of the canals lessened the ability of the company to meet the constantly increasing demand. There was a shortage as early as the winter of 1902-3; but the situation did not become serious until the following year, when the main canal, for a distance of four miles below the intake, became so silted up that it could not possibly carry the volume of water that was imperatively needed. An attempt was made to remedy this state of affairs by putting in awaste-gate, eight miles below the intake, for the purpose of sluicing out the channel in time of high water.

“The idea” (as stated byMr.Cory) “was to divert a large quantity of water during the flood season, waste it through the Best waste-gate, and in this way scour out the upper portion of the canal. At first, the action was as expected, and some two feet in the bottom were carried away. When, however, the river reached its maximum height, ... and carried an excessive silt content, especially of the heavier and sandy type, this scouring action was entirely overcome, and the bottom of this stretch was raised approximately one foot higher than during the previous year.”

This silting up of the main canal, and the consequent reduction of its carrying capacity, caused great injury to the agricultural interests of the Valley. Crops in many places perished for lack of water, and hundreds of farmers put in damage claims, which amounted in the aggregate to half a million dollars. In the late summer of 1904, it became evident that radical measures would have to be taken at once to increase the water supply. As the managers of the company had neither the financial means nor the requisite machinery for quickly dredging out the silted part of the canal, they decided,in September of that year, to cut a new intake from the river at a point about four miles south of the international boundary. This would eliminate the choked-up part of the canal, and let water directly into the part that was unobstructed.

The Three Headings (or Intakes), in Spring of 1905

If President Heber and Chief Engineer Rockwood had been aware of the fact that the Colorado was even then preparing to pour its waters into the Salton Sink, by making one of its semi-millennial changes of course, they might perhaps have fortified the western bank instead of cutting through it; but there was little or nothing to show the extreme instability of the conditions that were then determining the trend of the river across its delta, and the idea that it might burst through this intake and again turn the Valley into a fresh-water lake does not seem to have occurred to anyone. The cutting was therefore made and the water shortage relieved; but at the cost of imminent peril to the whole Valley and its twelve thousand inhabitants.

In view of the tremendous and disastrous consequences of this measure, it is only fair that Chief Engineer Rockwood should be allowed to state, with some fullness, his reasons for adopting it, and for failing to put in a head-gate to control the flow of water through thechannel and thus prevent its enlargement. In an article entitled “Born of the Desert,” published in the second annual magazine number of the Calexico Chronicle, in May 1909, he sets forth his reasons in the following words:

“As soon as the summer flood (1904) dropped, I discovered that instead of the bottom” (of the canal) “being lower, it was approximately one foot above that of the year previous.... We knew that with the dredging tools which we had it would be impossible to dredge out this four miles of canal in sufficient time for the uses of the Valley, providing the water in the river should drop as low as it had the previous year.... We were then confronted with the proposition of doing one of two things, either cutting a new heading from the canal to the river below the silted four-mile section of the canal, or else allowing the Valley to pass through another winter with an insufficient water supply. The latter proposition we could not face, for the reason that the people of the Valley had an absolute right to demand that water should be furnished them, and it was questionable in our minds as to whether we would be able to keep out of bankruptcy if we were to be confronted by another period of shortage in the coming season of 1904-1905.“The cutting of the lower intake, after mature deliberation, and upon the insistence of several of the leading men of the Valley, was decidedupon. We hesitated about making this cut, not so much because we believed we were incurring danger of the river’s breaking through, as from the fact that we had been unable to obtain the consent of the Government of Mexico to make it, and we believed that we were jeopardizing our Mexican rights should the cut be made without the consent of the Government. On a telegraphic communication, however, from our attorney in the City of Mexico, to go ahead and make the cut, we did so, under the presumption that he had obtained the necessary permit from the Mexican authorities. It was some time after this, in fact after the cut was made in the river, before we discovered that he had been unable to obtain the formal permit, but had simply obtained the promise of certain officials that we would not be interfered with, providing that plans were at once submitted for the necessary controlling structures to be placed in this heading.“... In cutting from the main canal to the river at this point, we had to dredge a distance of 3300 feet only, through easy material to remove, while an attempt to dredge out the main canal above would have meant the dredging of four miles of very difficult material. We began the cut the latter end of September and completed it in about three weeks. As soon as the cut was decided upon, elaborate plans for a controlling gate were immediately started, and when completed, early in November, were immediately forwarded to the City of Mexico forthe approval of the engineers of the Mexican Government, without whose approval we had no authority or right to construct the gate. Notwithstanding the insistence of our attorney in the City of Mexico, and various telegraphic communications insisting upon this approval being hurried, we were unable to obtain it until twelve months afterward, namely, the month of December 1905.“In the meantime, serious trouble had begun. We have since been accused of gross negligence and criminal carelessness in making this cut; but I doubt as to whether anyone should be accused of negligence, or carelessness, in failing to foresee what had never happened before. We had before us at the time the history of the river as shown by the rod-readings kept at Yuma for a period of twenty seven years. In the twenty seven years there had been but three winter floods. In no winter of the twenty seven had there been two winter floods. It was not probable, then, that there would be any winter flood to enlarge the cut made by us, and without doubt, as it seemed to us, we would be able to close the cut, before the approach of the summer flood, by the same means that we had used in closing the cut for three successive years around the Chaffey gate at the head of the canal.[9]During this winter of 1905,however, we had more than one winter flood. The first flood came, I believe, about the first of February, but did not enlarge the lower intake. On the contrary, it caused such a silt deposit in the lower intake that I found it necessary, after the flood had passed, to put the dredge through in order to deepen the channel sufficiently to allow water to come into the valley for the use of the people. This was followed shortly by another heavy flood that did not erode the banks of the intake, but, on the contrary, the same as the first, caused a deposit of silt and a necessary dredging. We were not alarmed by these floods, as it was still very early in the season. No damage had been done by them, and we still believed that there would be no difficulty in closing the intake before the approach of the summer flood, which was the only one we feared. However, the first two floods were followed by a third, coming sometime in March, and this was sufficient notice to us that we were up against a very unusual season, something unknown in the history of the river as far back as we were able to reach; and as it was now approaching the season of the year when we might reasonably expect the river surface to remain at an elevation that would allow sufficient water for the uses of the Valley to be gotten through the upper intake, we decided to close the lower.” (“Born of the Desert,” by C. R. Rockwood, Calexico Chronicle, May 1909.)

“The cutting of the lower intake, after mature deliberation, and upon the insistence of several of the leading men of the Valley, was decidedupon. We hesitated about making this cut, not so much because we believed we were incurring danger of the river’s breaking through, as from the fact that we had been unable to obtain the consent of the Government of Mexico to make it, and we believed that we were jeopardizing our Mexican rights should the cut be made without the consent of the Government. On a telegraphic communication, however, from our attorney in the City of Mexico, to go ahead and make the cut, we did so, under the presumption that he had obtained the necessary permit from the Mexican authorities. It was some time after this, in fact after the cut was made in the river, before we discovered that he had been unable to obtain the formal permit, but had simply obtained the promise of certain officials that we would not be interfered with, providing that plans were at once submitted for the necessary controlling structures to be placed in this heading.

“... In cutting from the main canal to the river at this point, we had to dredge a distance of 3300 feet only, through easy material to remove, while an attempt to dredge out the main canal above would have meant the dredging of four miles of very difficult material. We began the cut the latter end of September and completed it in about three weeks. As soon as the cut was decided upon, elaborate plans for a controlling gate were immediately started, and when completed, early in November, were immediately forwarded to the City of Mexico forthe approval of the engineers of the Mexican Government, without whose approval we had no authority or right to construct the gate. Notwithstanding the insistence of our attorney in the City of Mexico, and various telegraphic communications insisting upon this approval being hurried, we were unable to obtain it until twelve months afterward, namely, the month of December 1905.

“In the meantime, serious trouble had begun. We have since been accused of gross negligence and criminal carelessness in making this cut; but I doubt as to whether anyone should be accused of negligence, or carelessness, in failing to foresee what had never happened before. We had before us at the time the history of the river as shown by the rod-readings kept at Yuma for a period of twenty seven years. In the twenty seven years there had been but three winter floods. In no winter of the twenty seven had there been two winter floods. It was not probable, then, that there would be any winter flood to enlarge the cut made by us, and without doubt, as it seemed to us, we would be able to close the cut, before the approach of the summer flood, by the same means that we had used in closing the cut for three successive years around the Chaffey gate at the head of the canal.[9]During this winter of 1905,however, we had more than one winter flood. The first flood came, I believe, about the first of February, but did not enlarge the lower intake. On the contrary, it caused such a silt deposit in the lower intake that I found it necessary, after the flood had passed, to put the dredge through in order to deepen the channel sufficiently to allow water to come into the valley for the use of the people. This was followed shortly by another heavy flood that did not erode the banks of the intake, but, on the contrary, the same as the first, caused a deposit of silt and a necessary dredging. We were not alarmed by these floods, as it was still very early in the season. No damage had been done by them, and we still believed that there would be no difficulty in closing the intake before the approach of the summer flood, which was the only one we feared. However, the first two floods were followed by a third, coming sometime in March, and this was sufficient notice to us that we were up against a very unusual season, something unknown in the history of the river as far back as we were able to reach; and as it was now approaching the season of the year when we might reasonably expect the river surface to remain at an elevation that would allow sufficient water for the uses of the Valley to be gotten through the upper intake, we decided to close the lower.” (“Born of the Desert,” by C. R. Rockwood, Calexico Chronicle, May 1909.)

At the time when the first attempt to close the intake was made, the cutting was about sixty feet wide. A dam of piles, brush and sandbags was thrown across it in March 1905, but it had hardly been completed when another flood came down the Colorado and swept it away. A second dam of the same kind, built a few weeks later, shared the same fate. By the middle of June, the river was discharging 90,000 cubic feet of water per second; the width of the lower intake had increased from sixty feet to one hundred and sixty; water was overflowing the banks of the main canal and accumulating in the deepest part of the Sink; and a new Salton Sea was in process of formation.

Lower Intake at Time of Southern Pacific Loan

Such was the state of affairs whenMr.Harriman and the Southern Pacific Railroad Company first became directly interested in the problem of river control. Early in 1905, the California DevelopmentCo., finding itself in pecuniary difficulties, applied toMr.Julius Kruttschnitt, General Manager of the Southern Pacific, for a loan, on the alleged ground that the Imperial Valley was furnishing a great deal of traffic to the railroad, and the irrigation company was therefore warranted in asking for financial assistance.Mr.Kruttschnitt, however, declined to consider the application. Thepetitioners then addressed the President of the railroad company,Mr.E. H. Harriman, who, it was thought, might be induced to give the necessary aid, even though he had no personal interest in the Valley and no connection whatever with the California DevelopmentCo.Mr.Harriman, as a man of imagination and far-seeing vision, was naturally in sympathy with the bold attempt to irrigate and reclaim the arid lands of the Colorado Desert, and when the matter of the loan was presented to him, he not only gave it immediate consideration, but ordered an investigation and a report. He finally consented, against the advice ofMr.Kruttschnitt and other counsellors, to loan the Development Company $200,000, “to be used in paying off certain of its floating indebtedness and in completing and perfecting its canal system.” Inasmuch, however, as the financial management of the irrigation company had not always been judicious,Mr.Harriman and the Southern Pacific stipulated that they should have the right to select three of its directors, one of whom should be president, and that fifty one per cent of its stock (6300 shares) should be placed in the hands of a trustee as collateral security for the loan. This stipulation was agreed to, and on the 20th of June 1905, the SouthernPacific Company, as chief creditor, took temporary control of the California Development Company by selecting three of its directors, and by appointing as its presidentMr.Epes Randolph, of Tucson, who was then acting also as president of the Harriman Lines in Arizona and Mexico.[10]

WhenMr.Harriman and the Southern Pacific thus took over the management of the California Development Company, they had no intention of assuming its responsibilities, directing its engineering work, or deriving revenue from its operations. All they aimed to do was to see that the money loaned washonestly and judiciously spent. The financial management of the company, had not previously been above criticism, to say the least; andMr.Harriman was fully justified in taking such control as might be necessary to ensure proper expenditure of the funds that the Southern Pacific Company furnished. From the representations made by the Development Company at that time, it was thought that the lower Mexican intake might be closed at a cost of not more than $20,000, and the Company proposed to use the remainder of the $200,000 loan in “completing and perfecting its canal system,” under the direction of its own technical experts. When, however, President Randolph made a personal investigation of the state of affairs, shortly after his appointment, he found the situation much more serious than the Development Company had represented it to be, and telegraphedMr.Harriman that the Imperial Valley could not be saved by the expenditure of $200,000. To control the river, he said, under the conditions then existing, would be extremely difficult. Nobody could foresee what would be the ultimate cost of the engineering operations, but it “might easily run into three quarters of a million dollars.”

Mr.Harriman could have insisted, even then,upon a return of the unspent loan, and could have withdrawn from the financially hazardous undertaking; but instead of doing this, he telegraphed President Randolph: “Are you certain you can put the river back into the old channel?”Mr.Randolph replied: “I am certain that it can be done.” Then wiredMr.Harriman: “Go ahead and do it.”

As Chief Engineer Rockwood was thought to be familiar with the problem of river control, and quite competent to deal with it, he was allowed, at first, to take such measures for closing the intake as seemed to him best. He had made the cutting long before the Southern Pacific had anything to do with the irrigation of the Valley, and upon him, primarily, devolved the responsibility of averting consequences that might be disastrous.

Although the Mexican cutting, at that time, had virtually become a crevasse, the flow through it was not great enough to endanger the cultivated lands of the valley. The excess of water overflowed the banks of the canal—the old Alamo barranca—but it ran into the deepest part of the Sink, where it slowly accumulated without flooding anything except the works of the New Liverpool Salt Company. Civil Engineer C. E. Grunsky, of the U. S. ReclamationService, who made an inspection of the intake three days after the loan to the California Development Company, described the situation as “not serious, but sufficiently alarming to require some attention.” The most disquieting feature of it was the steepness of the incline toward the Imperial Valley as compared with that toward the Gulf of California. The fall of the Colorado from the intake to the Gulf was only one hundred feet, while that from the intake to the bottom of the Valley was nearly four hundred feet. As the distance was about the same, either way, the Valley incline was approximately four times as steep as the riverbed incline, and if the whole stream should break through the intake and go down the steeper slope, the velocity of the current would make the stopping of it extremely difficult, if not absolutely impossible. When a turbulent river, in flood, discharges at the rate of 100,000 cubic feet per second down an easily eroded and comparatively steep declivity into an immense basin four hundred feet deep, it soon gets beyond control.

The difficulty of dealing with these conditions was greatly increased by the impossibility of predicting or anticipating floods. The annual rise of the Colorado, above its junctionwith the Gila, begins in the spring, reaches its maximum in July, and subsides to normal about the middle of August. This period of high water is fairly regular and may be counted upon. Floods in the drainage basin of the Gila, however, are capricious, occur at all seasons of the year, and are particularly violent in the fall and winter months. “These floods,” asMr.Cory says, “are far more to be feared and reckoned with, in preparing and conducting engineering work along the lower Colorado River, than anything coming down the Colorado River proper,” partly because they come suddenly and unexpectedly, and partly because they carry immense quantities of driftwood. During the Gila flood of November 29-30, 1905, the water at Yuma rose ten feet in ten hours, with a maximum discharge of 102,000 cubic feet per second, while driftwood almost completely covered the water surface. Such floods, coming with little or no warning, are almost irresistible.

When, in July 1905, the summer flood in the Colorado began to subside, Chief Engineer Rockwood determined to fend off the main current, and lessen the pressure on the crevasse, by means of a jetty. Just opposite the intake was a bush-overgrown island, five eighths of amile long by a quarter of a mile wide, which split the river into two channels. Across the western channel, from the head of the island to the bank, a semi-barrier was built, of piling, barbed wire and brush. This obstruction, it was thought, might check the flow into the western channel, cause a deposit of heavy silt, and eventually create a bar which would deflect the main current around the northern end of the island and thus carry it away from the mouth of the crevasse. The attempt was only partly successful. A bar was formed, but it did not completely close the channel, nor deflect the main current. There was still an opening, about one hundred and twenty five feet in width, through which the rush of water was so great that it could not be controlled. The attempt to deflect the main current into the eastern channel, by means of a jetty, was then abandoned.

Up to this time, the Southern Pacific Company had not taken part directly in the work of river control. After the failure of the jetty, however, in August 1905, President Randolph sent his assistant,Mr.H. T. Cory,[11]to the sceneof operations, with instructions to confer with Chief Engineer Rockwood and ascertain what his views and intentions were.Mr.Rockwood, at that time, did not regard the situation as at all alarming. The flow through the crevasse, he said, was doing useful work in scouring out and deepening the main canal (the old Alamo barranca) and there was little danger that the whole river would go that way. He was not in favor of closing the enlarged intake altogether, because that would shut off the water supply of the Imperial Valley and cause more damage than was then being done by the river. The deeper part of the Salton Sink, he said, was a natural drainage basin, and as it was much below the zone of cultivation in the valley as a whole, the accumulation of water in it was not likely to do a great amount of damage.

“I told him,”Mr.Cory says, “that I thought the situation was serious, even granting all he said were true; that he would better shut the break right away, for while the water might be doing good work in enlarging the canal of the California Development Company, the situationwas dangerous; that it was playing with fire.”

Throughout the month of August 1905, the intake continued to widen, with the caving away of its banks, and in SeptemberMr.Harriman and President Randolph decided that another effort must be made either to close the break, or to regulate and control the flow of water through it. About the first of October, at the suggestion and under the supervision ofMr.E. S. Edinger, a Southern Pacific engineer, an attempt was made to close the channel west of the island by means of a six-hundred-foot barrier-dam of piling, brush-mattresses and sandbags. This dam, which was built in October and November at a cost of about $60,000, might perhaps have checked or lessened the flow through the crevasse if nothing unforeseen had happened; but on the 29th-30th of November a tremendous flood, carrying great masses of driftwood, came down the Gila and increased the discharge of the Colorado from 12,000 to 115,000 cubic feet per second. The dam could not withstand such pressure, and even before the peak of the flood was reached it went out altogether, leaving hardly a vestige behind. As a large part of the island was eroded and carried away at the same time,further operations in this locality were regarded as impracticable. The crevasse had then widened to six hundred feet, and nearly the whole of the river poured through it into the deepest part of the Sink, where there was already a lake with a surface area of one hundred and fifty square miles. The main line of the Southern Pacific, in many places, was almost awash, and the whole population of the Valley was alarmed by the prospect of being drowned out. If the break could not be closed and the river brought under control before the period of high water in the spring and summer of 1906, it seemed more than probable that sixty miles of the Southern Pacific track would be submerged; that the irrigation system of the California Development Company would be destroyed; and that the whole basin of the Imperial Valley would ultimately become a fresh-water lake.

The difficulty of dealing with this menacing situation was greatly increased by the necessity of furnishing an uninterrupted supply of water to the farmers of the valley while engineering operations were in progress. It would not do to shut the river out altogether, because that would leave without irrigation nearly two hundred square miles of cultivated land. TheColorado must be controlled, but not wholly excluded. Several methods of solving this problem were suggested, but the only two that seemed likely to succeed were advocated by Consulting Engineer Schuyler and Chief Engineer Rockwood.Mr.Schuyler proposed that a new steel-and-concrete head-gate be put in near Pilot Knob, where a solid rock foundation could be secured; that the four miles of silted channel be re-excavated and enlarged by a powerful steam dredge specially built for the purpose; and that the whole low-water flow of the river be then turned through this head-gate into the enlarged canal and thence into the Alamo barranca west of the break. By this means the settlers would be continuously supplied with water, while the crevasse-opening would be left dry enough to close with a permanent levee or dam. The whole work, it was thought, could be finished in three months, or at least before the coming of the next summer flood.

Chief Engineer Rockwood’s plan also involved the building of a new head-gate, but he proposed to locate it on the northern side of the intake, and to carry the whole low-water flow of the river through it by means of an excavated by-pass. This, too, would keep the settlerssupplied with water and leave the crevasse-opening dry while it was being closed. The chief objection to the latter plan was that the head-gate would necessarily be of wood, and would have to stand on a treacherous foundation of easily eroded silt which might possibly be undermined. Late in November, after full consideration, President Randolph decided to try both plans and to work on them simultaneously. Contracts for the structural steel and iron work for the concrete head-gate were let in Los Angeles; the machinery for the 850-ton floating dredge “Delta” was ordered in San Francisco; materials for the Rockwood head-gate were collected on the northern side of the intake, and work was pushed on all of these structures with the greatest possible energy throughout the winter. In spite, however, of all efforts, none of them could be finished in the allotted time. The steel-and-concrete head-gate was not completed until the 28th of June; the dredge “Delta,” owing to the partial destruction of San Francisco, was not ready until the following November, and even the Rockwood gate, on which alternate shifts of men had worked night and day, was not in working order until the 18th of April. Meanwhile, the summer flood of 1906 had begun, with a discharge of32,200 cubic feet per second through the crevasse. This flow would have exceeded the capacity of the Rockwood gate, even if it had been possible to turn the river through the by-pass that led to it, and the attempt to bring the Colorado under control was again temporarily abandoned.

Lower Intake in Spring of 1906 (showing site of Rockwood head-gate and first three attempts to close the break)

Then a long series of misfortunes and catastrophes followed, one after another. On the 18th of April, 1906, San Francisco was partially destroyed by earthquake and fire, andMr.Harriman hurried to the scene of the disaster for the purpose of affording help. President Randolph soon joined him there, and, at the first opportunity, described to him the almost desperate state of affairs in the Colorado delta. The California Development Company had used up the $200,000 loaned to it by the Southern Pacific the previous year; the river was still uncontrolled, and the impending flood threatened to inundate the Valley and deprive 12,000 people of their property and homes.Mr.Harriman was not a man to be daunted or “rattled” by a sudden and menacing emergency. “There, in the bustle and confusion of temporary offices, with the ruins of San Francisco still smoking, with the facilities of his roads taxed to the utmost in carrying people away from thestricken city, with the wonderful railway system which constituted his life work crippled to an unknown extent, and with the financial demands resulting from the disaster impossible to determine,” he consented to advance an additional sum of $250,000 for controlling the Colorado River and protecting the Imperial Valley. “It has always seemed to me,” writesMr.Cory, “that this was really the most remarkable thing in the whole series of extraordinary happenings.”

With the promise of this additional sum of $250,000, President Randolph returned to the Imperial Valley to take up again the fight with the runaway river. The flood, at that time, was steadily rising; the width of the crevasse had increased to a quarter of a mile, and the Colorado was pouring into the Salton basin more than four billion cubic feet of water every twenty four hours.

On the 19th of April, 1906, the day after the San Francisco earthquake,Mr.C. R. Rockwood, who had been the chief engineer of the California Development Company for about four years, tendered his resignation, andMr.H. T. Cory, President Randolph’s assistant, was appointed in his place. The Southern Pacific Company then assumed full control and direction of defensive operations, and all subsequentwork was planned and executed by its engineers, with the powerful support ofMr.Harriman and his great railway system.

Agricultural Sands Eroded and Destroyed by Flood Water

The task set before Messrs. Randolph, Cory, Hind and Clarke was one that might well have daunted even engineers of their great ability and experience. As the summer flood approached its maximum, in the latter part of June, the crevasse widened to more than half a mile, and the whole river, rushing through the break, spread out over an area eight or ten miles in width, and then, collecting in separate streams as it ran down the slope of the basin, discharged at last into the Salton Sea through the flooded channel of the New River barranca. Thousands of acres of land, covered with growing crops, were inundated, and thousands of acres more were so eroded and furrowed by the torrential streams that they never could be cultivated again. The works of the New Liverpool Salt Company were buried under sixty feet of water; the towns of Calexico and Mexicali were partially destroyed, and in many places the tracks of the Inter-California Railroad (a branch of the Southern Pacific) and the Holtville Interurban were deeply submerged or wholly carried away. The wooden flumes which carried the irrigating water overthe New River barranca were swept down into the Salton Sea, and 30,000 acres of cultivated land in the western part of the Valley became dry, barren and uninhabitable. At the height of the flood, the Colorado discharged through the crevasse more than 75,000 cubic feet of water per second, or six billion cubic feet every twenty four hours, while the Salton Sea, into which this immense volume of water was poured, rose at the rate of seven inches per day over an area of four hundred square miles. The main line of the Southern Pacific was soon inundated, and five times in the course of the summer the company had to move its track to higher ground.

A Flood Waterfall in Imperial Valley, Cutting Back

Nearer View of Flood Cataract in Imperial Valley, Cutting Back

The most dangerous and alarming feature of the situation was the “cutting back” of the torrents into which the flood-water collected as it rushed down the delta slope toward the Salton Sea. The fine silt of which the soil was composed washed out like powdered sugar, and wherever there happened to be a strong current, the flow soon produced a miniature rapid. The rapid then became a cascade, the cascade grew into a fall, and the fall finally developed into a roaring cataract, which “cut back,” upstream, at the rate sometimes of four thousand feet a day, widening as it receded, and leaving below it a deep gorge with almost perpendicularwalls. Some of the gorges eroded in the light friable silt by these receding waterfalls were fifty to eighty feet deep and more than a thousand feet across. It was estimated that the channels thus formed during the floods of 1906 had an aggregate length of more than forty miles, and that the solid matter scoured out of them and carried down into the Salton Sea was nearly four times as great as the whole amount excavated in the digging of the Panama Canal. But the damage actually done by these receding waterfalls was unimportant in comparison with the damage that they threatened to do. If one of them should “cut back” far enough to break into the irrigation system of the California Development Company, all the water in the latter’s canals and ditches would instantly flow down into the deep gorge below the cataract, and bring about a disaster almost unprecedented in history. The twelve thousand settlers in the desert oasis were wholly dependent upon the irrigation system for their supply of drinking water, and if that supply should be cut off, they would be compelled by thirst either to camp around the margin of the Salton Sea, which was ten or fifteen miles away from most of them, or else get out of the valley within forty eight hoursin a wild precipitate stampede. Paradoxical as it may seem, the danger of being driven out by lack of water was even greater and more immediate than the danger of being drowned out by the rising flood.

The changes in the topography of the Colorado delta brought about by the crevasse and the floods of 1906 were greater than any that had occurred there in the three preceding centuries of recorded history. In referring to themMr.Cory says:

“The effect of this flood, in a geological way, was of extraordinary interest and very spectacular. In nine months, the runaway waters of the Colorado had eroded from the New and Alamo River channels and carried down into the Salton Sea a yardage almost four times as great as that of the entire Panama Canal. The combined length of the channels cut out was almost forty three miles, the average width being one thousand feet and the depth fifty feet. To this total of 400,000,000 to 450,000,000 cubic yards must be added almost ten per cent for side cañons, surface erosions etc. Very rarely, if ever before, has it been possible to see a geological agency effect in a few months a change which usually requires centuries.”

Channel Cut by the Runaway River on Its Way to the Salton Sea

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 underMr.C. P. Huntington. After the latter’s death, he went to Los Angeles, where he built and managedMr.H. E. Huntington’s interurban system of electric railways and where he made the acquaintance ofMr.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 ofMr.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.

[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 underMr.C. P. Huntington. After the latter’s death, he went to Los Angeles, where he built and managedMr.H. E. Huntington’s interurban system of electric railways and where he made the acquaintance ofMr.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 ofMr.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.

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