Boulder Canyon Project - All-American Canal System

State: California
Region: Lower Colorado Basin Region

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History

The Imperial Valley lies between the Mexican boundary and the Salton Sea, bounded on the east by sandhills and on the west by the foothills of the San Diego Mountains. Coachella Valley is located in the Salton Sea Basin. It lies partly in Riverside County and partly in Imperial County, California. The valley is surrounded on all sides but the south by mountains and is about 50 miles long, 1 mile wide at the northern end, and 11 to 12 miles wide in the center. Ground water is present and before the Coachella Canal was constructed the land was irrigated with water from private wells. In 1853, interest was aroused in the possibility of irrigating these lands from the Colorado River. The legislature of California, in 1859, asked the Congress to cede 3 millions acres to the state of California for reclamation by irrigation. The Public Lands Committee of the House of Representatives acted favorably on this application, but in 1862 the bill failed to pass. The route proposed for the canal was practically the same as that used 40 years later for the Alamo Canal. The Colorado River Irrigation Company was formed in 1891-1892 and the entire problem of irrigating the Colorado River delta was carefully examined and important features worked out, but financial difficulties brought about failure of this company. The California Development company, formed in 1896, succeeded where the original company had failed and construction was begun in 1900. The first project to irrigate Imperial Valley was Alamo Canal. The canal delivered water to the upper channel of the Alamo river, which flows north toward the Salton Sea in the valley center, offering suitable opportunities for developing auxiliary distribution structures. By September 1904, nearly 8,000 valley settlers were operating 700 miles of canals and irrigating 75,000 acres. The Alamo Canal, however, was difficult to operate without upstream control of the Colorado river. The channel required almost constant dredging to control silt, and an extensive levee system was constructed for protection from flood damages. In spite of these precautions, the Colorado River, while carrying a major flood from the Gila River Basin, washed out the Alamo Canal heading in 1905. The river partially changed its course to follow the canal and the Alamo River into the Salton Sea. Water flowed into the interior for nearly 2 years and inundated some 330,000 acres. The Southern Pacific Railroad Company, alarmed about the threat to the prospering Imperial Valley and to the railroad through the basin, finally returned the Colorado river to its natural channel on February 10, 1907, and controlled diversion of irrigation water through the Alamo Canal was resumed.

Construction

Water shortages struck the Coachella Valley during construction of the Coachella Canal in 1947. Increasing demands for water and a declining water table combined to create a water shortage in the valley. Some well supplies fell while other wells failed completely. Many farmers deepened their wells to find the ever elusive supply of water. In 1948, Ashbach and Sons completed the concrete lining on their Coachella Canal contract. The company hauled all the concrete in transit mix trucks from one mixing plant. Wind arose in May and June 1948, hampering final completion of the contract. The wind blew large amounts of sand into the canal, forcing the contractor to clear it. The delay did not prevent Ashbach and Sons from completing the contract in June. Reclamation accepted the work June 26, 1948. Macco Corporation contracted construction of flood protection wasteways, including lining, earthwork, and structures in 1948. The company finished the protection works within the following year. The contractors on the main section of the Coachella Canal also completed their contracts in 1949. Work on the lateral system for the Coachella Canal commenced in 1949, and finished in May 1954. Contractors also completed an equalizing reservoir on the Coachella Canal on June 10, 1953. The Coachella Canal travels 123 miles northwest from the All-American Canal at Drop One. Initial capacity of the earth lined section is 2,500 cubic feet per second. The concrete lined section has a capacity of 1,300 cubic feet per second. The earth lined section of the canal is forty to sixty feet wide at the bottom with a water depth of 10.3 feet. The bottom width of the concrete lined section is twelve feet with a water depth of 10.8 feet. Construction of the All-American Canal began in 1934, following the construction of Hoover Dam. The first irrigation water was delivered in 1940. The construction of Imperial Dam and Desilting Works began in January 1936 and was completed in July 1938. Coachella Canal was built during the period from August 11, 1938, to June 1948. Construction was interrupted by World War II, and work stopped from 1942 to 1944. Construction of the Coachella distribution system was initiated in 1948 and completed in 1954 With an assured water supply, the increase in production of farm crops in the Imperial and Coachella Valleys has been phenomenal. The soils of these two valleys, combined with a favorable climate, have long been noted for production of fruits and vegetables that reach the market during the winter season when shipments from other areas are either nonexistent or at a minimum. The Nation`s domestic date gardens are concentrated primarily in the Coachella Valley, with 90 percent of this country`s production originating there. Other principal crops on irrigated farms are alfalfa, lettuce, cotton, carrots, citrus fruits, cantaloupes, watermelons, barley, tomatoes, sugar beets, grapes, sweet corn, and bell peppers. Imperial Dam forms a reservoir area with a nearly stable water surface elevation of 181 feet above sea level. Camping, hunting, picnicking, swimming, boating, and year-round fishing for bass, catfish, bluegill, and crappie are popular activities in the reservoir area. For many years in the nineteenth and early twentieth centuries, Californians searched for ways to bring water from the Colorado River to southern California`s Imperial Valley for irrigation purposes. The most natural route involved moving the water through Mexican territory. Early private interests recognized this and accepted it, building canals over the border in Mexico, delivering water to the Imperial Valley. Later, water users from the Imperial Valley requested Reclamation`s involvement in building a canal lying entirely in the United States, eventually leading to construction of the All-American Canal The All-American Canal System of the Boulder Canyon Project is closely related to Reclamation`s Yuma and Gila Projects as well as Hoover Dam, the flood control and storage structure of the Project. Imperial Dam, the only diversion dam in the system, diverts water to the All-American Canal from the Colorado River. The dam also diverts water to the Gila and Yuma Projects, and led to the abandonment of the latter project`s Laguna Dam as an active diversion dam. The All-American Canal System is located in Imperial County, California. Imperial Dam lies 303 miles south of Hoover Dam, and eighteen miles north of Yuma, Arizona. The All-American Canal travels west from Imperial Dam about eighty miles to a point ten miles past Calexico, California. The Coachella Canal branches off from the All-American Canal sixteen miles west of Pilot Knob and travels northwest 123 miles to the Coachella Valley in Riverside County. Imperial Dam also diverts water to the Yuma Main Canal of the Yuma Project, California and Arizona, and the Gila Gravity Main Canal on the Gila Project, Arizona. Temperatures recorded in the area range from 16 to 125 degrees fahrenheit. The annual precipitation averages 3.14 inches a year, and the valleys receive most of their water in the form of runoff from snow in the San Bernardino Mountains and Mount Jacinto. The resort city of Palm Springs, at the northern end of the Salton Sink, is the most famous community in the area. The Gulf of California once stretched 150 miles northwest of its current position, covering the Imperial and Coachella Valleys. The Colorado River gradually built its delta across the gulf from Pilot Knob, near Yuma, Arizona; to the Cocopah Mountains, south of Calexico, California. The delta created a natural dam across the gulf, leading to the evaporation of water from the Salton Sink. As a result most of the Imperial and Coachella Valleys lie below sea level. The California Legislature first proposed development and irrigation of the Imperial Valley, using water from the Colorado River, in the 1850s. The proposal involved diverting the Colorado to the Alamo River drainage area in Mexico. Then using natural channels the water would flow through the Alamo river back into California, for distribution by a canal system. The project required a Federal grant of three million acres of government land. The California Legislature approved the grant, but the bill failed to pass the U.S. Congress in 1862. In 1876, Lieutenant Eric Bergland of the U.S. Army Corps of Engineers investigated the feasibility of a canal route traveling entirely through the United States. Bergland`s report proved unfavorable, but he recommended the natural route through Mexico.(3) After the failure of state and Federal government plans for the Imperial Valley, private concerns entered the competition. Oliver Wozencraft, a physician from New Orleans, first considered the possibility of irrigating the Salton Sink in the 1850s. Unable to finance his plan, Wozencraft abandoned the idea. John Beatty`s establishment of the Colorado River Irrigation Company (CRIC) in 1892, plunged private business into Imperial Valley irrigation. The CRIC surveyed a route and planned to deliver water from the Colorado, in California, across the border to a short canal in Mexico. The canal would divert water into the Alamo River for transport north into the Imperial Valley. The CRIC failed to achieve its ambitious plan, and Beatty renamed the company the California Development Company (CDC) in 1896. Beatty brought in two partners and Charles Rockwood, to act as engineer. One of the new partners was George Chaffey, who already attained a reputation as an irrigation entrepreneur in Los Angeles and on the Murray River in Australia. The CDC built the Imperial Canal, extending diagonally from the Colorado River, with the headworks 500 feet north of the U.S.-Mexico border. Silt deposits at the headgates halted the flow of water to the canal. The stoppages caused water shortages in the Imperial Valley in 1903 and 1904. Mexico allowed the CDC to divert water from the Colorado in Mexico. The company cut a heading four miles south of the border. In 1905, the river washed out the heading and turned inland away from its normal course to the Gulf of California. For two years the Colorado flowed through the heading, flooding and eroding farm lands in the Imperial Valley, before entering the Salton Sink. Early trailblazers reported infrequent salt pools in the sink in 1853. The Colorado River made the Salton Sea permanent. Before the Southern Pacific Railroad Company closed the breach, the surface elevation of the Salton Sea increased from 275 feet below sea level to 201 feet below sea level. The water rose seven inches a day in 1906, and engulfed a salt refining works in sixty feet of water. The increasing size of the Salton Sea submerged an additional 298,240 acres of land. The Southern Pacific found itself obligated to close the breach because the flooding inundated the company's tracks across the Valley, and the California Development Company's resources proved too few to deal with the problem. California Development Co. reorganized in 1905, and as a result of its settlement with the Southern Pacific for repairing the breach in the canal and re-directing the river, control of the company`s affairs went to the Southern Pacific Land Company, a subsidiary of the Southern Pacific Railroad, that included the CDC`s Mexican corporation. CDC`s property was in a receivership from 1910 until 1916. In the meantime the Imperial Irrigation District (IDD) organized in 1914, and in 1916, the Irrigation District obtained the CDC`s property, including all the company`s stock in the Mexican corporation that managed all the CDC`s property in Mexico. The Coachella Valley County Water District (CVCWD) organized on January 16, 1918, under the County Water District Act of California. The CVCWD soon became part of the drive to irrigate the Imperial Valley with a canal located entirely in the United States. During the summer of 1904, Imperial Valley water users asked Reclamation to consider purchasing the California Development Company`s works for $3 million and complete the system under the auspices of the Reclamation Act of 1902. The U.S. Attorney General asserted the project`s international features legally prohibited Reclamation`s involvement. Furthermore, the Reclamation Service considered the asking price excessive. The roadblocks to Reclamation, however, failed to stop future considerations of a project in the area. In 1918, the U.S. government appropriated $15,000, and the Imperial Irrigation District appropriated another $30,000 to begin surveys and estimate the cost for a canal situated entirely in the United States. Elwood Mead, W.W. Schlecht, and C.E. Grunsky submitted the first report on July 22, 1919. Congress, felt the need for more information, and authorized Secretary of the Interior Franklin K. Lane to examine conditions of the Imperial Valley and major features of the project. The resulting "Fall-Davis Report" recommended a highline canal from Laguna Dam, on the Yuma Project, to the Imperial Valley. The report also endorsed construction of a storage reservoir at or near Boulder Canyon on the lower Colorado River. As a result, Congress approved the Boulder Canyon Act on December 21, 1928, providing for construction of present day Hoover Dam. The act further authorized a main canal, traveling entirely in the United States, connecting Laguna Dam, or another diversion dam, with the Imperial and Coachella Valleys in southern California. On March 26, 1929, the United States contracted with the Imperial Irrigation District and the Coachella Valley County Water District for investigating and estimating the cost for the type of canal authorized in the Boulder Canyon Act. The contract limited expenditures to $100,000, to be split equally between the government and the two districts. Two sites were considered. One recommendation proposed a canal from Laguna Dam. The second location started at a diversion dam five miles upstream from Laguna and had an elevation twenty-one feet higher than the other proposal. Reclamation Engineer Homer J. Gault directed the investigation, completing the field work in May 1930. Gault submitted the final report in May 1931, recommending the diversion dam and desilting works five miles upstream from Laguna Dam. The report set the location for the All-American Canal in approximately its final position. Reclamation also planned to use the All-American Canal to divert water to the Siphon Drop Powerplant, on the Yuma Project, and from there into the Yuma Main Canal, eliminating the need for Laguna Dam. The canal's immediate purpose was to provide an adequate supply of desilted water to the almost 500,000 acres already irrigated by the canal Imperial Irrigation District's system. The Irrigation District contracted with Reclamation on December 1, 1932, for construction of a diversion dam, main canal and structures, and delivery of water. The repayment contract's major provisions specified: construction by Reclamation; a final cost not to exceed $38.5 million; assumption of operation and maintenance by the Irrigation District; method of repayment; diversion and delivery of water for the Yuma Project; delivery of water from Boulder Dam by Reclamation; and development of hydroelectric power. On October 15, 1934, the Coachella Valley County Water District entered into a repayment contract with Reclamation specifying a diversion dam, main canal and structures, and the delivery of water. Raymond M. Priest was the first Construction Engineer for the All-American Canal. After Priest`s death on July 6, 1934, Roy B. Williams became the Construction Engineer for the Project. The Yuma Project office handled preliminary clerical work until the All-American construction headquarters could be put in the new Federal building in Yuma. Reclamation established a survey tent camp on the Colorado River about twenty-five miles above Yuma with plans to move it as work progressed. All-American Canal The size of the All-American Canal convinced Reclamation to separate construction into several schedules. Besides the contracts, Reclamation also carried on a significant portion of the work by force account. Sixteen companies received contracts for work on the canal, not including subcontractors or bond companies forced to complete work (see Table. I). Work on the canal started in 1934. The Griffith Company contracted one of the most difficult excavation schedules on the All-American Canal. Schedule Seven ran through two rock ridges on the east side of Pilot Knob. Griffith started excavation on August 8, 1934, experiencing considerable difficulty in drilling the rock because of seams and the irregular condition of the formation. The company managed to excavate over 150,000 cubic yards of rock before the end of 1934. The Griffith Company excavated 35,833 cubic yards of common material and 522,582 cubic yards of rock, completing Schedule Seven on August 22, 1935. In the midst of the Great Depression and severe drought of the 1930s, Imperial Valley farmers and other citizens, like others around the United States, suffered from unemployment and financial difficulties. In an attempt to alleviate the problem, the Board of Directors of the Imperial Irrigation District requested $1 million for force account labor on part of the Canal in the Imperial Valley. The allotment served as a relief measure for the unemployed and farmers suffering from the shortage of irrigation water during 1934. The force account labor employed 250 men and 1,000 head of horses and mules. All the men and teams were hired through the Federal Re-employment Office in El Centro, California. In 1935, the Southern Sierras Power Company protested a loan given to the Imperial Irrigation District under the Emergency Relief Appropriation Act of 1935. The loan enabled the Irrigation District to build generating, transmission, and distribution facilities to provide electricity to the Imperial and Coachella Valleys. Southern Sierras argued the proposed works would duplicate adequate electrical facilities in existence and infringe on the power company`s market share. Southern Sierras further maintained the power facilities failed to qualify for Public Works Funds because the work would compete with private industry and was not useful, among other lesser reasons. The company said construction of the All-American Canal would furnish ample relief work. The power company`s arguments proved to be in vain and the Irrigation District eventually had their power facilities. Continued construction in 1936, required conclusion of right of way negotiations. Reclamation secured contracts with several mining groups to guarantee canal right of way above Laguna Dam. A contract with the Southern Pacific Railroad granted a right of way for the All-American Canal over the railroad right of way at Araz Junction and provided for a bridge at that point. The canal right of way crossed the Picacho and Castle Dome cemeteries, forcing Reclamation to relocate the remains from both to Potholes, California. Two contracting companies became financially unstable while working on the canal, forcing their bond companies to take over the work. Peterson Construction Company, already plagued by work stoppages, suffered financial difficulties during 1937, forcing their bond company, Seaboard Surety Company, to take over the contract. Atlas Construction Company became unable to finish its contract for construction of turnouts, checks, culverts, and temporary metal and timber flume crossings on the All-American Canal in 1939. The company`s surety, Fidelity and Deposit Company, of Maryland, assumed responsibility for the contract. Fidelity and Deposit sublet the contract to MacDonald and Kahn, Inc. Reclamation completed repairs and rehabilitation of the Siphon Drop Powerplant of the Yuma Project in 1938, under the auspices of the Boulder Canyon Project--All-American Canal System. Reclamation rehabilitated the Siphon Drop Powerplant in order to increase its generating capacity. Reclamation`s work on the powerplant also linked the All-American Canal to the Yuma Main Canal for supplying irrigation water to the Yuma Project. V.R. Dennis Construction Company and their subcontractors finished a check and wasteway near Pilot Knob on June 27, 1938. Norman I. Fadel contracted to construct a turnout from the All-American Canal to the Yuma Main Canal and the Siphon Drop Powerplant, four drainage outlets, and a turnout from the Siphon Drop Powerplant forebay to an existing lateral serving lands in the Fort Yuma Indian Reservation. Some citizens of Calexico wanted the All-American Canal to travel through the city. Reclamation felt the damage resulting from any breaks in the open canal would not be worth the risk. Reclamation considered two alternatives through Calexico using conduits travelling under the streets of the city, crossing the New River through pipes or conduits. The cost for running the canal through Calexico would have been $186,760 to $382,358 more than the route around the town. Reclamation decided to skirt Calexico with the canal.( Sharp and Fellows Contracting Company received the contract to build the combination siphon and wasteway over the New River and started construction of the New River Siphon, carrying the All-American Canal over the New River, on March 8, 1937. Sharp and Fellows poured the inclined barrels at the inlet and outlet of the steel pipe sections monolithically, in one solid section without joints. The company finished the siphon on August 6, 1938. Southwest Welding and Manufacturing Company started finishing, erecting, and painting the 196-inch diameter plate steel pipes for the New River Siphon in October 1938, and finished the next year. Reclamation completed acquisition of rights of way for most of the All-American Canal in 1939, except for some parcels through the more heavily farmed section of the Imperial Valley. Title complications delayed closing the sections. The Act of August 30, 1890 (26 Stat. 391) reserved right of way for canals and ditches constructed under the authority of the United States. As a result, payment for the rights of way only covered damages to improvements, not for the land. Reclamation did purchase three parcels near the Alamo River for borrow pits and building sites.( In 1939, all contract work on the All-American Canal ended. Final construction on the canal consisted mainly of work on the power drops. Lewis-Chambers started Drop One and the Coachella Turnout on July 24, 1938, progressing slowly during the year, but picked up the pace in 1939. The company finished the contract on July 6, 1939. Work crews completed the other power drops during the same year. The Imperial Irrigation District installed the generating machinery for the powerplants. Seepage proved a continual concern on the canal throughout construction. In 1937, compacted lining was placed where the canal traversed material too porous to prevent excess seepage losses, and Frank Doran placed clay sewer-pipe drains parallel to the All-American Canal on both sides in the Calexico area. The pipe carried off seepage water which otherwise might flow into adjacent farm lands. In 1940, Reclamation constructed intercepting drains along the All-American Canal through the Reservation Division of the Yuma Project and on East Mesa near the East Highline Canal as needed. The drains prevented canal seepage from settling into ponds on nearby cultivated lands. The drains kept out the accumulation of water which otherwise would damage crops and land. Actual water delivery started in the spring of 1940. An earthquake in May 1940 destroyed some of the Imperial Irrigation District`s canal. The District received permission from Reclamation to divert water from the Central Main Canal until repairs could be affected. The All-American Canal continued receiving water from the IID`s Mexican canal system until water diverted at Imperial Dam reached the western canals. Official water delivery through the All-American Canal started in October 1940. The inaugural ceremonies took place on October 12, 1940, at the turnout to the East Highline Canal of the Imperial Irrigation District. Reclamation Commissioner John C. Page gave the keynote address at the celebration. Upon final completion, the All-American Canal stretched eighty miles, from Imperial Dam to just west of Calexico, California. The bottom width of the canal averaged 160 feet, with a water depth of twenty-one feet. The canal`s diversion capacity reached 15,155 cubic feet per second. Much of the All-American Canal`s path skirts the U.S.-Mexico border as it travels west. Imperial Dam Reclamation constructed the government camp site for Imperial Dam one and one half miles downstream from the dam site, starting September 17, 1935. The camp included an air-conditioned office, an air-conditioned twenty-eight man dormitory, four four-room residences, six three-room residences, four two-room residences, seven two-car garages for residences, a dormitory garage, and a combination garage/warehouse/shop. A 100 foot deep, twelve-inch, cased well pumped water to the 30,000 gallon steel supply tank, standing sixty feet high, which held the camp`s water supply. Reclamation conducted clearing operations on the reservoir site for Imperial Dam. Dense areas of arrow weed, willows, mesquite, and other local plant life covered the site. Reclamation cleared the area prior to construction work to facilitate survey work and allow bidders to better study the dam site. Reclamation employed Native Americans from the nearby Fort Yuma Indian Reservation to clear the site using hand tools. Reclamation awarded the contract for construction of Imperial Dam to Morrison-Knudsen Company, Inc., Utah Construction Company, and Winston Brothers, Inc., three of the companies that built Hoover Dam, on December 14, 1935. The three contractors received the notice to proceed January 14, 1936, and started work two weeks later. Orders for Changes, issued shortly after the contract award, required construction of a desilting basin for the Gila Gravity Main Canal, a concrete apron upstream from the units of the headworks, and reinforced concrete sheet piling for the division walls of the inlet channels Morrison/Utah/Winston established a temporary camp east of the All-American Canal, and started constructing a permanent camp 900 feet west of the Canal. They completed fifty buildings by the end of 1936. The structures erected consisted of a eight man dormitory, two sixteen man dormitories, fifteen twenty-four man dormitories, twenty-eight one-family residences, two office buildings, one hospital, and one mess hall/commissary/recreation building. The contractors raised a secondary camp for laborers with families who could not be taken care of in the main camp, or who chose to establish their own quarters. The companies provided electricity, treated water, and bathing facilities. Left to their own devices, the secondary camp residents used trailer, tents, frame buildings, and cabins for living quarters. Initially, Reclamation counted ninety-six families in the camp, but believed there might be more. A later census revealed 253 residences in the area with a population of 812 inhabitants. The contractors provided two police officers and Reclamation provided another, who was also deputized as a county health officer and agriculture inspector. An owner of a quarter section, one mile from the dam site, built some temporary cottages to rent to workers. The contractors supplied electricity and water to the owner under agreement that the granting of any concessions on the property needed the contractors' approval, to guarantee a uniform policy for all residents. Eventually about sixty families lived at the third camp. Work on the dam site began with construction of a 3,400 foot long cofferdam to block the river from the diversion works and construction site. Then Morrison/Utah/Winston started work on the desilting basins, driving sheet-piling under the outer banks of the outlet channels on January 26, 1936, and finished the work the following May. The companies began placing the eighteen inch dry rock paving in the desilting basins on May 15, 1936. At first they used rock excavated from Basin One, but after depleting that source, the contractors then opened a rock quarry on the Arizona side of the Colorado. Work crews started excavating the California abutment on April 6, 1936. By June 3, they were ready to place the first concrete, completing most of the work by December 3, 1936. Excavation for a footing to some of the All-American Canal headworks extended more than fifty feet and went below the elevation of the river bed. To keep river water out of the excavation, workers drove a line of steel sheet-piling into the rock around the work area. Seepage required three six inch and three four inch pumps to discharge water from 219 wellpoints driven into the sand around the inside of the piling, for eight days before placing the concrete. Seepage continued through the rock itself, causing problems for the work crews. The pumps removed 1,500 gallons per minute from the footing during concrete placement, and a system of tile and gravel drains brought the water to a central point to pump out. After finishing the work, the contractors filled the drains with grout to seal them. The Morrison/Utah/Winston contract included the beginning of the Gila Gravity Main Canal. Work started on September 28, 1936. The canal required construction of the left embankment, in addition to canal excavation using material channel excavation and a borrow pit. At the end of 1936, Morrison/Utah/Winston employed 1,035 men on the dam construction, excluding government and company officials. Morrison/Utah/Winston set up concrete mixing plants on both the Arizona and California sides of Imperial Dam. The contractors placed all the concrete possible before diversion of the river, nearly completing the All-American Canal headworks by the end of 1937. Some of the work completed included installation of the twenty-three foot high, seventy-five foot long roller gates in the headworks during 1937. Work crews finished most of the Gila Gravity Main Canal headworks on June 14, 1937. Morrison/Utah/Winston began closing the downstream cofferdam in late March 1937, using surplus material from excavation to construct it. Excavation of the diversion channels started on May 17, 1937, and the contractors completed them on July 12. Morrison/Utah/Winston started excavation of sections of the dam on July 17, 1937, and closed the upstream cofferdam at midnight two days later. The contractors completed all of the excavation on October 23, 1937. Two minor floods struck the Imperial Dam site in February 1937, but did no damage. Early warning of the flood conditions allowed sufficient preparation to deal with the problem. During the year, dam construction had an average of 800 workers, from a low of 520 to a high of 1,280 during peak construction. On May 3, 1937, the contractors and the American Federation of Labor (AFL) reached an agreement under which the dam construction would only employ union men. Morrison/Utah/Winston finished the concrete on the overflow weir, the section where the Colorado River flows across, with the placement of twelve units. The contractors levelled gravel ballast, stockpiled in the units before final placement of concrete, and graded it to form a fill nine feet deep. Work crews formed a drainage channel along the downstream weir wall to pass water from the drains in the foundation to the outlets in the downstream surfaces of the weir. Morrison/Utah/Winston maintained stability in the channel by paving the bottom and slope with twelve inch thick, dry rock paving. The contractor placed a massive riprap section downstream from the overflow weir. Excavation for the section reached twenty-eight feet deep. The companies surrounded the area with wellpoints to help dewater the site, but work crews could only remove water down so far, forcing them to place some of the riprap under six feet of water. The contractors resumed driving the twenty foot steel sheet-piling for cutoff walls, and placement of concrete and riprap for the sludge pipe outlets in conjunction with construction of the training dike on the sluiceway. Work finished on the influent channel structures in two desilting basins, and concrete work on the transitions from the gate structures for three bypass. Morrison/Utah/Winston lined the desilting basins with rock paving embedded in gravel. Final work included the control structures for the desilting works. Heavy rains on the headwaters of the Bill Williams River, a Colorado River tributary in the northeast corner of Arizona, in early March 1938, caused flooding on the Colorado which suspended all construction on the Arizona side. The flood waters threatened the contractors` construction bridges across the diversion channels downstream from the gate structure. The Colorado started rising March 4, reaching flood levels by March 9. Morrison/Utah/Winston removed stop logs from Basin Three`s gate structure to pass the flood waters. The contractors replaced the stop logs when the water subsided, having done no damage. Work on Imperial Dam finished July 30, 1938. Reclamation completed some construction on the dam by force account because materials and equipment did not arrive before the contract deadline. The contractors began dismantling the construction camp on the right bank, downstream from the desilting works, in the early part of June. Morrison/Utah/Winston left their wood construction bridge, originally meant to be temporary, in place to use for maintenance work. Reclamation held dedication ceremonies at Imperial Dam on October 18, 1938. Secretary of the Interior Harold L. Ickes gave the keynote address to the audience. As part of the celebration, Reclamation turned the first water into the headgates of the All-American Canal. The central overflow section of Imperial Dam is a hollow section 1,198 feet long and 31 feet high. The hollow sections contain gravel ballast to give it the weight necessary for stability. The overflow weir is a `floating` type, resting on a twelve foot layer of compacted earth on top of the gravel bed of the Colorado. At the end of construction Imperial Dam was the highest concrete or masonry dam built as a floating weir. The non-overflow section of the dam is a concrete slab and buttress weir standing eighty-five feet high, which adds 2,277 feet to the length of the dam. The All-American Canal and Gila Gravity Main Canal headworks sit on either side of the dam, resting on fifty foot concrete pilings. The All-American Canal`s desilting works at Imperial Dam consist of six settling basins arranged in pairs. Each basin is about 269 feet wide and 769 feet long, set at a sixty degree angle to the influent channels. The influent channels are concrete and have a diminishing cross-section. The water feeds through vertical slots, tipped with iron which reduce the velocity and turbulence of the water, and distribute it evenly into the basins. The water flows across the basins to the effluent/bypass channels. The water travels across an overflow weir, remaining in the basin for twenty-one minutes, depositing 80 percent of its silt. Seventy-two rotary scrapers with 125 foot diameter, remove the silt into collecting trenches. The silt is then forced into sludge disposal pipes and through a sluiceway channel leading back into the river below Imperial Dam. Coachella Canal The Coachella Valley County Water District had over 161,000 irrigable acres in the district, but only 16,000 acres received irrigation water pumped from wells. A lack of runoff and increased development of land combined to make well pumping necessary. When construction of the All-American Canal System started the district looked there for a new water supply. W.E. Callahan Construction Company and J.P. Shirley started the first excavation of the Coachella Canal on August 11, 1938. The combined companies finished seven and one half miles, and excavated over two million cubic yards of material before the end of the year. Their work progressed steadily on the first forty-three miles of the canal the following year. Reclamation awarded the contract for the second forty-three miles of Coachella Canal to Morrison-Knudsen and M.H. Hasler in 1939. The Morrison/Hasler contract included construction of thirty-one double box siphons, one round barrel siphon, five checks, four automatic spillways, and five drainage inlets. The firms subcontracted some of the work out to various companies. The main contractors started work September 9, 1939.(43) Work on the Coachella Canal progressed well in 1940. Callahan-Shirley excavated 1,334,615 cubic yards of material, bringing their total of excavation to over nine million cubic yards. Morrison/Hasler excavated eighteen and one-half miles of the Coachella Canal and another seventeen and one-half miles for diversion channels during the year. During 1940, the companies finished work on fourteen siphons, substantially completed eight more, and started another. By the end of 1941, the contractors completed over seventy-five miles of the Coachella Canal. During the year Morrison/Hasler excavated twelve miles of their contract. The companies completed concrete work on the contract June 7, 1941. When high temperatures struck in May and early June of the year, the contractors laid the concrete during the night to keep the concrete temperatures below ninety degrees, as per Reclamation`s specifications for the Project. Reclamation opened bids on October 27, 1941, for twenty-two miles of concrete lined canal, but the United States` entry into World War II forced Reclamation to reject all bids. In 1942, the War Production Board suspended all work on the Coachella Canal, except the Morrison-Knudsen/M.H. Hasler contract already in effect. The firms completed excavation of storm drains and dikes, and placement of rock riprap around the structures and dikes on March 8, 1942. By the end of the year, the contractors nearly finished the contract. Labor shortages caused by the war hindered Morrison-Knudsen/Hasler sufficiently for the contractors to request an extension past the December 24, 1942 deadline. Morrison-Knudsen/Hasler concluded work on the contract March 22, 1943. In 1944, the scarcity of labor, materials, and repair parts continued hampering work on the Coachella Canal. Nevertheless, Reclamation resumed work largely postponed in 1942-43. John Bohannen received a contract to build thirteen six-room residences and twelve five-room residences for Reclamation employees stationed at Coachella. On March 9, 1944, Reclamation awarded a construction contract on twenty-two miles of the Coachella Canal to J.F. Shea, Inc., who bid low at just over $1.6 million. Reclamation issued the notice to proceed on May 2, 1944, but labor and equipment shortages prevented the contractor from starting until October 3, 1944. The canal line in Shea`s contract started through rough and badly cut up terrain, slowing work considerably. By the end of 1944, Shea had only excavated one quarter of a mile of the canal. Labor shortages continued to slow construction in 1945. John Bohannen completed construction of the twenty-five residences for Reclamation employees at Coachella. Because the camp lay outside of Coachella, separate water, sewer, and electrical systems had to be constructed for them. The Chicago Bridge and Iron Company built a 50,000 gallon elevated water tank to supply the camp. During 1945, J.F. Shea completed most of the excavation work on the contract, but accomplished none of the concrete work. Delays kept Shea from starting the concrete work until December 14, 1945. Heavy rains struck the Coachella Valley on August 18, 1945. The resulting runoff flooded the lower portion of the valley. The flooding caused some damage to compacted areas of a drainage inlet, canal banks, construction roads, and other structures on Shea's contract. Shea estimated damages at $25,000, but Reclamation officials considered the firm's estimate excessive. Reclamation awarded a contract in 1944, to Vinnell-Engineers, Ltd., for a check and a drop. When the contractor completed the work, Reclamation forces installed stop logs and turned water into the Coachella Canal on January 20. M.H. Hasler received a contract to line twenty-three miles of canal and surface about forty-nine miles of road with clay. The company completed the road surfacing and the twelve-inch canal lining January 16, 1945. In 1946, Reclamation awarded a contract to J.F. Shea for eleven miles of canal with a bottom width of twelve feet lined with concrete. The contract included a nine mile dike to form a detention basin. Shea teamed with Morrison-Knudsen for two Coachella contracts. The two companies acknowledged the notice to proceed on the first contract on March 16, 1946. Reclamation awarded the second contract on April 15, 1946, but Reclamation officials complained the contractors did not accomplish any significant work during the year. J.F. Shea completed one stretch of canal in 1947, including six wash overchutes. A lack of reinforcement steel initially delayed work, which continued progressing slowly because of the deficiency of skilled labor. On March 20, 1947, flood waters flowed behind the canal's concrete lining at four of the wash overchutes under construction, damaging the canal lining. Shea repaired the damage and completed the cleanup before summer. Reclamation accepted the six overchutes on June 6, 1947. Shea and Morrison-Knudsen concluded work on their first contract of the Coachella Canal on July 14, 1947. Late delivery of materials postponed final completion. Reclamation's Chief Engineer Walker R. (Brig) Young extended the contract an extra 105 days to allow for delayed arrival of construction materials. Slow material transfers further hindered the two companies' second contract. The delays forced the contractors to use their own reinforcement steel for the concrete work. Shea and Morrison-Knudsen finished the contract in fall 1947, and Reclamation accepted the work October 3. Reclamation awarded the contract for a reach of the canal to Otto B. Ashbach and Sons on January 10, 1947. Continuing negotiations between Reclamation and the Coachella Valley County Water District, for a supplemental repayment contract, delayed issuance of the notice to proceed until May 28, 1947. The negotiations for the new repayment schedule arose because costs had reached the maximum allowed by the 1934 contract. Reclamation studied a proposal on the Ashbach contract to reduce the canal section downstream of the central main turnout, but discarded the idea because of increased cost. Ashbach and Sons progressed slowly on the contract, but by the end of the year, the contractor extended the Coachella Canal past the Palm Springs highway. Reclamation forces built a maintenance depot near Coachella Canal. The depot included a large quonset hut to serve as a garage; two twenty by forty foot tropical huts provided a shop and warehouse; fueling facilities included a 2,000 gallon diesel oil storage tank and a 2,000 gallon gasoline storage tank; a loading dock; sewer lines; a septic tank; and water supply lines at the depot. Reclamation laid canal lining on the southern end of the Coachella Canal by force account in 1947. Reclamation forces placed a twelve inch layer of uncompacted clay on the banks and bottom between Siphons One and Six. They spread the clay across the slopes and sides with bulldozers.

Plan

Irrigation water is diverted from the Colorado River at Imperial Dam through desilting basins into the All-American Canal on the California side and the Gila Gravity Main Canal on the Arizona side. These two canals and their branches carry water to their respective project areas, where the water is then delivered to the lands through distribution systems. The Imperial Dam and Desilting Works are situated on the Colorado River 18 miles northeast of Yuma, Arizona. The purpose of the dam is to raise the water surface 25 feet and provide controlled gravity flow of water into the All-American and Gila Gravity Main Canals. The desilting works remove most the sediment carried by the Colorado River. This sediment removal prevents clogging of the canals and subsequent, expensive, difficult maintenance. To meet the irrigation diversion requirements at Imperial Dam, the flow of water in the Colorado River arriving at the dam is controlled by releases from Parker Dam, 150 miles upstream. Hoover Dam, 303 miles upstream; Davis Dam, 235 miles upstream and Glen Canyon Dam, 657 miles upstream; along with other dams, provide essential flood protection and storage. Ordinarily, the quantity of water released from these dams is coordinated with annual downstream requirements. However, during years of high runoff from the mountains, any extra water that cannot be held in allotted reservoir space is released at rates designed to minimize flooding while maintaining essential flood storage space in the reservoirs. Senator Wash Dam, Reservoir, and Pumping-Generating Plant are located in California 2 miles upstream from Imperial Dam. Senator Wash facilities were not constructed as part of the All-American Canal System, but are an integral part of operations at Imperial Dam. Senator Wash is an offstream regulating reservoir. When the flows arriving at Imperial Dam from the Colorado River exceed diversion demands, water is pumped into the reservoir and released at a later date when demands are greater than the flow arriving at Parker Dam. The reservoir created by Imperial Dam initially had a capacity of 85,000 acre-feet. This storage capacity was not considered a project feature and, as anticipated, the reservoir quickly filled with sediment. The reservoir capacity is now considered to be 1,000 acre-feet and intermittent dredging is required to maintain required diversion capacity at the Gila Gravity Main Canal Headworks. Imperial Dam is a reinforced concrete structure of the monolithic slab-and-buttress type consisting of an overflow weir, canal headworks at each end of the dam, and a sluiceway located between the All-American Canal Headworks and the overflow weir. The dam is 3,472 feet long, including a 490-foot rockfill dike at the Arizona end. The overflow weir is 1,197.5 feet long and designed to pass a flow of 142,000 cubic feet per second. The overflow weir, in conjunction with the California Sluiceway, is designed to pass a maximum flood of 185,000 cubic feet per second, not including any diversions to the canal systems. The two canal headworks are equipped with trashracks to prevent large pieces of debris from entering the canal systems. Ordinarily daily removal of the accumulation of trash is required. Trash removal is accomplished by an electrically powered rake device which pulls the trash up and dumps it into small, rail-mounted cars. The cars are moved to a chute where the trash is dumped into a truck and hauled to a disposal site where it is either burned or buried. The design of the desilting works for the All-American and Gila Gravity Main Canals are significantly different. The Gila facility consists of a concrete-lined basin, which allows sediment to settle to the bottom while clear water is skimmed off the top as flows pass over the diversion control gates into the canal. The All-American Canal Desilting Works are more elaborate. The flow into the canal is controlled at the headworks before the water passes through the desilting works rather than after, as at the Gila facility. The headworks consists of four roller gates, each 75 feet long and 22 feet high, including apron and flash weir. Downstream from the roller gates are four concrete channels with vertical concrete walls between the channels. Three of the channels carry water to the three existing desilting basins. The fourth channel was constructed to serve a fourth basin if found to be needed. All four channels are equipped with gates to permit water to bypass the basins through effluent channels when necessary. The three basins are separated into halves by a long tapered influent channel with the vertical slots along the sides designed to evenly distribute water entering the basin. The water crosses each basin half at a low enough velocity to allow the sediment to settle to the bottom, where it is moved by rotating scrapers to a central pedestal containing a rotating mechanism and piping system. The clear water near the surface flows over weirs, that comprise the long sides of the basins, into effluent channels leading to the All-American Canal. The pipe system under each basin half discharges the collected sediment, along with the necessary water to move it, into the California Sluiceway. The combination of water and sediment is refereed to as sludge The California Sluiceway extends from the 12 radial gates, located between the All-American Canal Headworks and the overflow weir, downstream about 3,000 feet. As sediment collects in the sluiceway, it is moved downstream by high rate, short duration (sluicing) flows of water discharged through the sluiceway gates. The sluicing flows usually are 8,000 cubic feet per second released for a 20-minute period, although many different flow rates, time periods, and combinations of gates are used. This procedure also removes some sediment from Imperial Dam Reservoir. Prior to 1964, the sediment from the desilting basins found its way down the river and, as water was diverted from the Colorado River, a disproportionate amount entered the Mexican irrigation system. As a means of resolving this problem, a channel was constructed in 1964 from the end of the California Sluiceway to the reservoir area above Laguna Dam. A large settling basin was excavated about midway in this 4-mile-long channel to collect the sediment moved out of the sluiceway. Dredges pump the sediment from the settling basin to the adjacent flood plain. The first dredging operation started in 1965 and has since been intermittently required about every 2 years. The sluicing flows from Imperial Dam are stored behind Laguna Dam and released over extended periods. Laguna Dam releases become part of the water delivered to Mexico. This procedure requires considerable fluctuation of the reservoir elevation, which limits the value of Laguna Reservoir as a recreation resource. The California Sluiceway is also used to discharge excess water flows arriving at Imperial Dam that are not pumped to Senator Wash Reservoir or diverted to the canals. It is preferred to keep water from passing over the overflow weir to prevent damage to roads and other facilities immediately below Imperial Dam. The All-American Canal serves the Imperial and Coachella Valleys in southern California and the Yuma Project in California and Arizona. The canal has a design capacity of 15,155 cubic feet per second from the desilting works to Siphon Drop, 14.7 miles downstream. From Siphon Drop, the capacity reduces to 13,155 cubic feet per second for another 6 miles to Pilot Knob. The capacity of the canal is 10,155 cubic feet per second for the next 15.5 miles to Drop No. 1 where the Coachella Canal starts. From Drop No. 1, the canal continues west, parallel to the Mexican border for another 44 miles, gradually reducing in capacity from 7,755 to 2,655 cubic feet per second. At this point, the canal connects with the Westside Canal about 10 miles west of Calexico (about 80 miles from Imperial Dam). The design capacity of the All-American Canal includes 155 cubic feet per second for the City of San Diego, California; however, the San Diego diversion point has been changed from Imperial Dam to a point above Parker Dam. Water is diverted from All-American Canal to most of the Reservation Division of the Yuma Project in California at four turnouts between the Laguna Dam area and Siphon Drop. A turnout at Siphon Drop diverts water to the Yuma Main Canal for the Valley Division of the Yuma Project in Arizona plus some areas of the Reservation Division. Pilot Knob facilities include a powerplant and wasteway. Much of the water required to meet Mexican treaty requirements is diverted from the Colorado River at Imperial Dam into the All-American Canal and is returned to the Colorado river through Pilot Knob Powerplant, thus creating a significant production of electricity. Otherwise, water is delivered to Mexico through the Yuma Main Canal; from the Colorado River below Laguna Dam; and from drains, wasteway flows, and Gila River flows. The Pilot Knob Wasteway automatically discharges water from the All-American Canal when the canal elevation becomes to high. The total length of canals and drains operated and maintained by the Imperial Irrigation District is about 3,161 miles. The distribution system was constructed by the district and consists of 1,472 miles of laterals. The drainage system consists of about 112 miles of closed drains and 1,341 miles of open drains. The district has constructed hydroelectric powerplants at Pilot Knob and Drop Nos. 2, 3, and 4 with capacities of 33,000, 10,000, 9,800, and 19,600 kilowatts, respectively. From its turnout at Drop No. 1 on the All-American Canal, the Coachella Canal proceeds in a northwesterly direction for 123 miles. The first 49 miles, originally constructed as unlined canal, have been replaced with a concrete-lined canal. The last 37 miles of the canal are also concrete lined, which still leaves 37 miles unlined. The original unlined canal had a capacity of 2,500 cubic feet per second; the recently constructed, concrete-lined canal has a design capacity of 1,550 cubic feet per second. As part of the Colorado River Basin Salinity Control Project (Title I, Public Law 93-320, June 24, 1974), the congress provided for lining the first 49 miles of the canal to recover most of the water lost by seepage. To maintain water deliveries during construction and avoid wet areas caused by seepage, a separate canal running nearly parallel to the original unlined section was designed. Construction of this newly relocated canal began in 1979 and was completed and put into operation in late 1980. The concrete-lined canal is estimated to save 132,000 acre-feet per year. The Coachella Valley County Water District`s distribution system, designed and constructed by the Bureau of Reclamation, is largely underground. The system consists of gravity flow concrete pipelines, with a few small pumping plants serving the higher areas. The network of laterals totals about 495 miles. Completed in 1949, the protective floodworks along the east side of the Coachella Valley consist of two detention dikes along the canal and three wasteways to carry floodwaters impounded by the dikes to natural drainage channels, and protect the main canal and distribution system from possible storm damage. A rehabilitation and betterment program, essentially completed in 1977, added a remote control system, terminal regulating reservoir, additional flood control structures, demossing screens, and other improvements. In 1988, Reclamation experimented with a state of the art method of lining. Called in-place lining, a canal can be lined with polyvinyl chloride (PVC) and concrete while water is flowing in the canal. In August of 1988, Reclamation awarded a contract to line 1.4 miles of the canal between Siphon 14 and 15. The contract was finished in April 1991. The All-American Canal below Pilot Knob was transferred to the Imperial Irrigation District for operation and maintenance on March 1, 1947. The district assumed responsibility on May 1, 1952, for those works above Pilot Knob including the All-American Canal Headworks, desilting basins, and the first 49 miles of the Coachella Canal. On December 7, 1982, the operation and maintenance of Laguna Dam, all Senator Wash facilities, and the remainder of Imperial Dam were transferred to the district. The lower 74 miles of the Coachella Canal and protective works were transferred to the Coachella Valley Water District on March 25, 1949, for operation and maintenance. The distribution system in the Coachella Valley was transferred to this district in 1954. On November 1, 1982, the operation and maintenance of the initial 49 miles of the Coachella Canal were transferred to the district.

Contact

Title: Boulder Canyon Operations Office Manager
Organization: Boulder Canyon Operations Office
Address: PO Box 61470
City: Boulder City, NV 89006-1470

Contact

Title: Public Affairs Officer
Organization: Lower Colorado Regional Office
Address: PO Box 61470
City: Boulder City, NV 89006-1470
Fax: 702-293-8333
Phone: 702-293-8000

Contact

Organization: Imperial Irrigation District
Address: PO Box 937
City: Imperial, CA 92251
Phone: 760-482-9600

Contact

Organization: Coachella Valley Water District
Address: PO Box 1058
City: Coachella, CA 92236
Fax: 760-398-3711
Phone: 760-398-2651

PROJECTS & FACILITIES

Boulder Canyon Project - All-American Canal System

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