- Journal of SD History
Chapter 9: Making a River
The giant dam on the Colorado River was completed in 1935. The river was at last brought under control and placed at the service of an ever-widening empire of the West.
First called Boulder and later to be named Hoover Dam, it differed from other river development projects in the United States in that it was not built at the expense of the general taxpayer. The electricity generated by the release of water stored in its reservoir, and sold to private as well as public power companies, would repay its cost.
California's share of the annual flow of the Colorado had been apportioned among various agencies, all of them in Southern California, both as to amounts and priorities. San Diego, next to last on a list of six, was allotted the 112,000 acre feet on which it had filed.
The total for Southern California, of 5,362,000 acre feet annually, would soon be challenged and water experts were well aware that even with the Colorado River, it would not be possible to put water on more than nine percent of Southern California's 50,000 square miles.
While the citizens of San Diego still hesitated in accepting the idea of going as far as the Colorado River for water to drink, no matter the warnings of Phil Swing, Hiram Savage and Fred Heilbron, the Metropolitan Water District had gone ahead with an aqueduct system across some of the most desolate country of the Southwest. No other water in the world was carried as far or lifted as high.
In those days the California Desert was just beginning to become a winter playground. Much of it had not been surveyed and the first task was the contour mapping of 25,000 square miles. The few roads that existed were merely trails, and water was available only in a few widely separated wells drilled deep into the sand. Selection of a route had been a process of many years. In one of its reports, the Metropolitan Water District recalled:
By the end of 1930 surveys had been made and estimates prepared for literally hundreds of lines. These lines covered most of Southern California, not in a symmetrical or uniform manner but as sort of irregular network, knotted together by controlling geographical features.
Unlike the wagon trails of the pioneers, these lines headed for mountain passes to avoid the long and hazardous tunnels required by more direct alignment. Where the wagon trails went over the top of passes, the aqueduct could not follow because of limiting grades or the excessive cost of pumping. Controlling divides must be penetrated by tunnels, and mountain passes...usually represent weak spots in the mountain barrier where the rock is broken, easily eroded, and subject to caving. Some of the passages into the coastal area are traversed by earthquake faults which are a hazard to any kind of underground construction. Some were waterlogged.
A route known as the Parker route was selected, as the safest and most economical, to ultimately deliver 1,212,000 acre feet of water, or a billion gallons daily, to the coastal population. In 1931 the voters of the district, which by then comprised thirteen cities; approved a bond issue of $220,000,000 by a ratio of five-to-one. Even before Boulder Dam was finished, work was started on a second dam 155 miles downstream, which would re-store water released from the lake behind Boulder Dam to provide a pool for diversion for the Metropolitan system. It was from here that the water would start its long journey to the coastal plain of Southern California.
While Parker Dam was built by the federal government with $13,000,000 furnished by the Metropolitan District, it also would serve to regulate the flow of the river below Boulder for the benefit of all downstream users. Anchored in a red canyon of the Whipple Mountains, it was called the deepest dam in the world. Engineers had to go 240 feet below the level of the stream, through silt deposited by ages of time, to reach bedrock, while its height above the stream was about seventy feet.
The water for thirsty Southern California was to be taken at an elevation of 450 feet above sea level. But on its course westward it would have to pass a desert basin dropping below sea level and confront a mountain range with a peak of more than 10,000 feet.
Even before the water could begin its journey it had to be lifted from the lake to be formed behind Parker Dam and taken up the side of the Whipple Mountains, in order to provide for a gravity flow until the next hilly barrier was reached. Through the release of water at Boulder Dam the river was made to provide its own lifting power, in the generating of electricity.
Pumps were designed to lift the water 291 feet, almost straight up, and send it through a short tunnel where it was again lifted 303 feet. Then at an elevation of more than a thousand feet, it entered another tunnel and emerged on the other side of the mountains, to flow sixty miles through siphons and open canals in a barren and arid country.
At Iron Mountain where it met its second barrier of hills the water was lifted 144 more feet and sent through another tunnel ten miles long, from where it could be turned to the southwest. A dozen miles beyond rose the Coxcomb Mountains, which in the brightness of the day look as if they had been scorched by a flame from the sun. This necessitated another tunnel of four miles in length.
In the next thirty-five miles the water had to be lifted twice in the Eagle Mountains. First it was lifted 438 feet to an elevation of more than 1400 feet. The next and last lift on the long run to the coast was at a place identified as Hayfield. This was a lift of 441 feet to 1800 feet above seal level and a total lift of 1617 feet. From there it was all downhill. But that did not mean that the worst was over.
The aqueduct was now nearing the most historic pass of Southern California, San Gorgonio, lying between the San Bernardino Mountains to the northeast and the San Jacinto Mountains to the southwest. The pass provided a gentle rise, from sea level to 2500 feet, through the coastal mountain barrier that had so frustrated the earliest explorers and pioneers. It was a natural railroad pass, and when the Southern Pacific chose this route to reach the coast, San Diego lost its race for commercial equality with the rising cities of the West.
The water would run at an elevation 1800 feet higher than the low point of the upper portion of the desert's Coachella Valley. It would have about sixty miles to go before entering a tunnel the engineers were driving through the San Jacinto Mountains. The water could not be dropped down to the desert floor to be pumped up again, nor supported at such a height and length by a Romantype aqueduct. But there was a natural aqueduct system in the San Bernardino Mountains.
Almost forty miles of continuous tunnel were dug along the dry slopes of the desert side of the mountains, so the water could be made to run gently downhill to meet the land as it rose in the upper part of San Gorgonio Pass. At a place called Cabazon above Palm Springs the aqueduct was taken underground across the pass to reach the base of the San Jacinto Mountains at an elevation of 1536 feet.
The base of the mountains was thirteen miles thick. And it was one of the strange features of Southern California that the green valley lying beyond the mountains was at a lower elevation than the desert on the inland side. The San Jacinto Mountains stood between the coastal plain and the desert, and the western slopes caught the rain and the east side did not.
J. L. Burkholder, who was assistant general manager of the Metropolitan District, later recalled that at the time they heard of Indian legends of fish inside the mountains. Shafts for the tunnel started from both directions. In July of 1934 miners working eastward from the west portal encountered an earthquake fault which loosened a reservoir of water that had been locked within the mountains. Three times water was pumped out, but the flow never ended. The tunnel had been started in May of 1933 and a year and a half had been required to dig two miles. The contractors gave up. The engineers of the Metropolitan District took over. They advanced by pumping liquid cement against the flow of the water at tremendous pressures, thus stopping up the fissures through which the water was pouring. When they reached the main faults they pushed through with the aid of powerful pumps, temporary supports and other special methods. At one time the flow of water reached eighty-eight cubic feet a second.
The tunnel was completed November 19, 1938. Its two shafts came together with only a tenth of an inch difference in elevation and none laterally. The point where the water would emerge on the cooler side of the mountains was forty-four feet lower than the entrance to the tunnel. Its point of destination was the terminal reservoir ten miles southwest of Riverside at an elevation of about 1400 feet. From the reservoir, 242 miles from the Colorado, the water would be distributed to the district cities, and to the communities and agricultural areas to be added in the future. After coasting downhill for 115 miles, at this point the water would still be almost a thousand feet higher than when it had started its journey.
From there it was only seventy miles by gravity flow to possible storage basins in San Diego. But the interest there in becoming a member of the Metropolitan District was not very high; for that matter, there was little concern over a crisis that might arise in some distant future.
The capacity of San Diego's existing system of dams and impounding reservoirs in the higher country and the pumping plants taking water from sands in the lower valleys had been built up to a net safe yield of 26.6 million gallons a day. This was considered adequate to serve a population of 200,000. The addition of the proposed San Vicente Dam and reservoir would add enough for a population, it was thought, of 260,000.
When the time came that San Diego had to reach to the Colorado for water, it was felt that the city should build its own aqueduct and pumping system and be the undisputed master of its future. The key to this sense of security was the All-American Canal. Nothing like it had been attempted in the United States and it was designed to serve the largest single irrigated acreage in the Western Hemisphere.
More than 4,000,000 acre feet of water would be required every year to irrigate the desert lands already broken to the plow, or soon to be. This meant enough water to cover 4,000,000 acres to a depth of one foot. The total cost of the project, with the Imperial diversion dam and the All-American Canal and its Coachella branch, was put at $38,000,000. The Imperial Valley Irrigation District committed itself to repay its proportionate share, $25,000,000, over a period of forty years.
There were some indications, however faint, that the farmers of the valley were not to be independent as they had believed. The canal was to be designed to also assist Mexico and federal participation carried with it the shadow of future influence.
The task confronting engineers was to bring into being a river in a desert, half a city block wide at its surface and twenty-two feet deep, that would carry almost nine times as much water as the Metropolitan Aqueduct. The capacity of the canal was to be 15,155 cubic feet of water per second, the 155 representing the allotment for San Diego of 112,000 acre feet annually.
North of Yuma the Colorado ran 150 feet above sea level in a bed of silt it had built up over thousands of years, and thus higher than the low land it was to water in the Imperial Valley. But between the river and the farms was a high and stubborn mesa and a five-mile wide ridge of sand hills which stretched in a north-south direction for thirty miles before dying out in Mexico. It was these two barriers which had forced the farmers of the valley to divert their water near the border and route it through Mexico.
Before a spadeful of earth was turned, the canal began to take form in models and drawings. In an outdoor laboratory experimenters made miniature canals, heaping up samples of materials, sprinkling and tamping them with rollers, and creating model embankments with varying degrees of slopes. With instruments they gauged the density of the banks, measured the percolation when exposed to water, and learned exactly how steep the banks should be made. In a report on the planning and early construction, the Popular Science Monthly in 1936 added:
But the most serious problem of all was that of crossing the valley of walking sand dunes, a Sahara-like waste of towering sand hills that slowly migrate under the influence of the wind. Reckless indeed seemed the engineers who dared to undertake the job, but careful observations of the dunes dispelled some of their terrors. The migration, though constant, was quite slow. A high embankment thrown up of the material excavated from the canal would adequately guard against encroachment by the walking sand hills.
It was because of these same hills that the early immigrant trails and later the Butterfield Overland Stage route had followed a circuitous course passing through Mexico for more than fifty miles.
The digging of the canal and construction of its diversion works began a year and a half after the start of the Metropolitan Aqueduct. As with the aqueduct, the All-American Canal needed its own system for diverting water from the river. The point selected was in the lower hills of the stark Chocolate Mountains, 148 miles below Parker Dam and 180 feet in elevation. The river valley is wide here and the diversion dam of the Bureau of Reclamation was 3485 feet long with one end resting in California and the other in Arizona.
This was a multi-purpose project, diverting water for domestic and agricultural users in the Bard, Imperial and Coachella valleys of California, and for the Wellton-Mohawk, Gila and Yuma valleys and the Yuma Mesa in Arizona. For the All-American Canal the dam lifted the level of the river thirty-one feet to enable the water to be diverted into a man-made channel above the flood plain of the river.
There was more to the problem of diversion than merely providing a new and convenient channel. The Colorado was ladened with vast amounts of silt which choked up the Alamo Canal in Mexico and was carried to the fields of Imperial Valley. Farmers constantly had to relevel their land and between 1923 and 1930 the district had spent an average of more than three-quarters of a million dollars annually for silt control.
The reservoirs higher on the river would retain much of the silt, but still sand and dirt picked up on the lower river were expected to be a costly nuisance and it was considered necessary to build a system of desilting basins below Imperial Dam where the water could be "laundered" and cleansed of its unwanted material.
The new channel, or canal, built up with the silt of the plain paralleled the course of the river southward, until it met the low hills and gravelly terraces extending from the foothills of the Chocolate and Cargo Muchacho mountains, and form the Pilot Knob mesa. Here, as with the Metropolitan Aqueduct, the water was to flow through an excavated canal cut through the hills above the old Laguna diversion dam, and, avoiding a direct challenge of the sand hills and the East Mesa, it would head for the international border and Pilot Knob.
Pilot Knob is a rocky eminence which got its name from the days when shallow-draft steamboats plied the Colorado River. At Pilot Knob the canal was in the approximate area of the original Hanlon Heading which had diverted water into the Alamo Canal. By following this route it would be possible to supply water to Mexico, either by a return flow to the river or by a direct discharge into the Alamo Canal.
In twenty miles the drop in water elevation had been about twelve feet. Yet the water level in the canal still would be fifty-seven feet above the river, enough to permit the development of hydro-electric power in the diversions to Mexico. The elevation above sea level was 167 feet.
To go around Pilot Knob would have taken the canal into Mexico. So the engineers went through it, blasting out a curving channel in its shoulders. On the other side, the canal turned along the border, once again riding thirty-three feet above the valley and little Mexican settlements just to the south.
The canal then was diverted in a northwesterly direction and cut across Pilot Knob mesa and taken up through the east edge of the sand hills. At a low point in the yellow hills the canal turned abruptly and sliced through them in a southwesterly direction toward the international border, passing through a gap in the hills known as Buttercup Valley. The depth of the cut through the sand hills varied from approximately fifteen feet to ninety feet and averaged about forty-five feet.
At the border it was swung westward in almost a straight line for fifty miles and a downhill slide of 174 feet across the East Mesa and into the garden lands. The elevation at the edge of the mesa at the sand hills is 160 feet above sea level. The mesa slopes westward at the rate of five feet a mile, but at its western edge, it falls off forty-five feet in five miles.
The flow was by gravity and at three different places a sharp drop was provided to supply falling water for generating electric power. Just beyond Calexico it reached its end at minus 6.65 feet. On the eighty-mile course the total drop was about 186 feet. The Imperial Valley stretched away in the distance, to the north, with all of its irrigated acreage lying below the level of the sea.
The All-American Canal was dug at a time when machines were replacing mules and horses in construction work. As the depression had made marginal farming uncertain, farmers of the valley were invited to bring their horses and "fresnoes" and help in building what they thought would be their own canal. More than 1000 animals competed with what Popular Science described as "herds of mechanical mastadons":
Ahead of the construction crews came surveyors and rodmen with transit and chain, staking out a path through the sage brush and cactus. Behind them followed gangs of Indians, who cut away harsh brush with hooked, sharp instruments resembling medieval battle axes. Tractors broke the virgin soil, loosening the earth and picking up heavy material. Where the surface was low, farmers drove four-horse teams pulling "fresnoes," or scrapers, to cut and fill...in their wake came big machines. Steam shovels, diesel tractors and bulldozers puffed and snorted. Trucks, by the hundred, piled high with excavated material, began to thunder over crude highways.
New marvels of the beginning of a technical age were used to do most of the major digging, particularly through the sand hills. They were drag-line excavators:
No larger digging machines ever walked the earth than the drag-lines that scoop out the main contours of the canal. Twenty freight cars are required to carry the dismantled parts of such machines. A 100-car train was needed to bring in the equipment used in digging a single thirty-mile stretch.
When the 650-ton machine was ready to travel, it literally walked ahead on its own feet. Two shoes, each weighing some 42,000 pounds, were mounted eccentrically on an axle forty-five feet long. As the axle turned, first one shoe and then the other moved to propel the drag-line ahead, at seven feet a step.
The man who had conceived the idea of the All-American Canal, Mark Rose, and many of the other original pioneers were still alive. In the closing years of their lives, they were able to witness the triumph over nature that climaxed a struggle begun at the turn of the century:
Under the scorching noonday sun, under the huge, desert moon, through summer heat and blinding sand storms, the work will go on. At night, the powerful glare of floodlights attached to the booms makes daylight where they work. Before water can flow, sixty million cubic yards of material must be excavated and hauled to its proper place--enough, loaded upon standard forty-foot gravel cars, to make a trainload 2235 miles long, stretching from Chicago to Los Angeles.
But more than a colossal job of earth-moving, more than the biggest irrigation ditch ever built, is this huge gash engineers are cutting in the southern desert. In combination with Boulder Dam, it not only will bring life-giving water to parched desert lands, but will permanently end the menace of the millions of tons of water that thunder down the Colorado's steep-walled chasm.
In a few years, with the completion of the canal, farmers would be relieved of the dread of recurring floods and periods of low or little water.
A second and smaller though longer branch canal was to water the Coachella Valley. Eventually it would be 123 miles long and curve around the upper end of the Salton Sea. In the future were to be other canals, to water the East Mesa and the 125,000 acres of the West Mesa lying between the Imperial Valley and the foothills of the Coastal Mountains.
The decision for San Diego was whether, when the time was right, to join the Metropolitan District or connect with the proposed West Mesa canal and lift the water over the mountains with its own pumps, canals and tunnels. The city's hydraulic engineer, Hiram Savage, who had pressed for studies on bringing Colorado River water to San Diego, had died in 1934. In 1936 the city retained three consulting engineers to study the problem and make recommendations.
Their report became known as the Ready, Hill and Buwalda report and it was submitted the following year. It concluded that though the future rate of growth of San Diego would be less than the rate for the decade of 1920 to 1930, it would continue at a fairly high level as the Pacific Coast and Southern California areas developed. It estimated that in 1960 there would be 320,000 persons in San Diego and about 370,000 in the metropolitan area. By the year 2000, it was predicted the population of the city would exceed 500,000.
While full development of all local resources was recommended, the report said that additional water would be needed from the Colorado between the years 1950 and 1960, and the most economical way to get a supply of twenty-five million gallons daily would be by the All-American Canal. The cost of building its own facilities was given as about half that of joining the Metropolitan District and assuming a fair share of the cost of its aqueduct and distribution system.
The West Mesa Canal would require two lifts, one of fifty feet and another of 112 feet. Water would be conveyed for a distance of fifty-four miles to a point in Borrego Valley east of Julian. It generally would follow the course of San Felipe Creek, which ambled down from the mountains across the desert to the Salton Sea. To get through the mountains at an elevation of 1000 feet would require a tunnel twenty-seven miles long. Instead, the report recommended that the water be carried twenty-six miles up the east slopes. This would require a tremendous lift of 2700 feet, 1100 feet more than the combined lifts of the Metropolitan Aqueduct. Again San Diegans were reminded of the high barrier and the absence of low, straight passes that had made road building so difficult and costly, and railroads virtually impossible.
At a point near Banner, a tunnel more than seven miles long would be dug through the mountains, passing just south of Julian. On the west side the water would be dropped 1800 feet and delivered to El Capitan Reservoir. The location of the tunnel was chosen because it was outside of known active earthquake faults.
Oddly, during the boom of the 1880's a promotional syndicate interested in selling land had proposed taking water in the opposite direction. It suggested a reservoir in Banner Canyon and drilling a tunnel 3000 feet long up into the Cuyamaca Mountains, to tap the melting snow and bring life to the "rich empire plains known as the Colorado Desert."
While the Ready, Hill and Buwalda plan was considered practical it was not known when the proposed West Mesa Canal, so important to the project, would be built. No money had been appropriated and no plans drawn. If San Diego experienced another prolonged drought, it was thought an emergency pipeline could be laid in the open over the mountains and down to one of the laterals of the All-American Canal.
There was no use thinking about the Colorado River if the voters did not proceed with ratifying an agreement with the federal government providing for capacity in the All-American Canal to carry water for San Diego. This had not yet been done. And the engineers suggested that as an initial step, in providing both a permanent and emergency supply ahead of actual need, it might be possible to justify construction of the San Felipe Tunnel with federal aid. It would require four years to complete it. Until these things were done, the report concluded that formation of a Metropolitan District for San Diego County, along the lines of the one serving the communities surrounding Los Angeles, was not necessary.
The report was read and it was generally agreed that it ably charted the future course for San Diego. But the local reservoirs were rich with water and the winters had been kind, and unlike the people of Imperial Valley, San Diegans had forgotten how it was to live on the edge of disaster.
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