40,000 Angelenos arrive by car, wagon and buggy to celebrate the opening of the Los Angeles Aqueduct at the Cascades in present-day Sylmar. Mulholland rises to begin the ceremony. He thanks his assistants and the city of Los Angeles for their loyal support. His address to the crowd is brief: "This rude platform is an altar, and on it we are here consecrating this water supply and dedicating the aqueduct to you and your children and your children's children — for all time." He pauses for a moment as if contemplating his words. Satisfied, he says abruptly, "That's all," and returns to his seat amid a tremendous roar from the crowd. When the din subsides, he is recalled to bring forth the water. The good-natured but noisy crowd quiets as Mulholland unfurls the American flag from staff at the speaker's stand. This is the signal to Gen. Adna R. Chaffee, president of the Board of Public Works during the aqueduct period, to perform the honored task of opening the gate valves. At Chaffee's command, five men atop the concrete gatehouse put their weight to the great wheels that will lift the gates and release the water into the canal. At the first trickle, the crowd breaks and runs to the canal. Hundreds of cups are dipped to the sparkling water. Horses rear in fright as the crowds cheer and horns blare. The band plays "Yankee Doodle Dandy." The program called for Mulholland to turn the aqueduct over formally to Mayor J.J. Rose, who would accept it on behalf of the people. However, all semblance of order is lost. Mulholland turns to Rose, next to him on the platform, and says, "There it is, Mr. Mayor. Take it."

Construction of Powerhouse No. 1 is completed in San Francisquito Canyon.

Construction of Powerhouse No. 2 is completed in San Francisquito Canyon.

L.A. sees unprecedented growth as homes and businesses spread across the Los Angeles basin.

Both Los Angeles and the Owens Valley face water shortages. There had been several years of subnormal snowfall in the Eastern Sierra. Meanwhile, local water use on privately owned land in the Owens Valley is increasing. Los Angeles lacks a dam and storage reservoir to control the flow of the Owens River above the aqueduct intake at Independence. The best site, Long Valley, remains in Eaton's hands after Mulholland rejected Eaton's asking price for the land. To increase supply, the city begins pumping groundwater. Farmers in the Independence area file injunctions in hopes of arresting the fall of water table levels. In Bishop and Lone Pine, residents grow alarmed at the city's purchases of properties north of Independence for the acquisition of groundwater rights.

The Owens Valley water wars begin. Wilfred and Mark Watterson are Inyo County's financial leaders. Owners of the Inyo County Bank, the Wattersons organize valley residents into a unified opposition force through the formation of an irrigation district. Confrontations ensue and escalate. Farmers diver water illegally, leaving the canal empty. The city had purchased land and water rights indiscriminately, leading to accusations of "checker boarding." Frustration and uncertainty prevail; area farmers feel vulnerable, unsure of the intentions of their neighbors. More and more valley residents believe Los Angeles should buy out the entire area.

The first violence erupts. Forty men dynamite the Lone Pine aqueduct spillway gate. No arrests are made. Eventually, the two sides fight to a stalemate. Los Angeles officials believe the wholesale purchase of the district is unnecessary to meet the demand for water. Instead, on Oct. 14, they hatch a plan that would leave 30,000 acres in the Bishop area free of city purchases. The city also offers to help promote the construction of a state highway to the area, thus creating a local tourist industry. The Wattersons and the directors of the Owens Valley Irrigation District reject the proposal, insisting on outright farm purchase and full compensation for all townspeople.

Mark Watterson leads 60 to 100 people to occupy the Alabama Gates, closing the aqueduct by opening the emergency spillway. Renewed negotiation ends the occupation.

Finally, the conflict is completely centered on the issues of farm purchases and reparations to the townspeople. Attacks on the aqueduct begin anew in April, and by July, there have been 10 instances of dynamiting. Just as the controversy reaches its zenith, valley resistance is suddenly undermined. The Wattersons close the doors of all branches of the Inyo County Bank. Not only are Wattersons bankrupt; they will also be tried and convicted of 36 counts of embezzlement.

Amid concerns about the water wars as well as earthquakes on the San Andreas Fault cutting off the aqueduct, Mulholland builds a series of reservoirs around Los Angeles to provide a reserve of water for the city.

Preliminary studies and surveys for the St. Francis Dam and reservoir are completed. Originally, the planned site of the big new reservoir is Big Tujunga Canyon, above present-day Sunland in the northeastern San Fernando Valley. But the high values placed on the necessary ranches and private lands are, in Mulholland's view, highway robbery. He ceases his attempts to purchase the land.

Construction of the St. Francis Dam begins. Originally planned to be 185 feet high, the dam is twice raised by 10 feet to a total of 205 feet without increasing the diameter of the base. The dam is unwittingly built against an ancient Paleolithic landslide on its eastern abutment. A number of errors are made in the construction of the foundation of the dam, except at its center section. The mixture of the concrete is also of questionable quality and workmanship.

Construction of the St. Francis Dam is completed.

Water begins to fill the reservoir.

The reservoir is filled to just three inches below the crest of the spillway and Mulholland orders that no more water be turned into the St. Francis.

While conducting his usual inspection, damkeeper Tony Harnischfeger discovers a new leak in the dam's western abutment. Concerned not only because other leaks had appeared in this same area in the past, but more so because the muddy content of the runoff he observes could indicate the water is eroding the dam's foundation, he immediately alerts Mulholland. Mulholland and his assistant Harvey Van Norman arrive and begin inspecting the area of the leak. Van Norman discovers the source and, by following the runoff, determines that the muddy appearance of the water is coming not from the leak itself, but from a place where the water came into contact with loose soil from a newly cut access road. The leak is discharging 2 to 3 cubic feet of water per second (15 to 22 U.S. gallons), by their estimation. (They later testify during the coroner's inquest that the volume being discharged was inconsistent.) Twice as they watch, both men notice an acceleration or surging of the flow. Mulholland believes some corrective measures are needed, although he thinks this can be done on some future date. For the next two hours, Mulholland, Van Norman and Harnischfeger inspect the dam and various leaks and seepages, finding nothing out of the ordinary or of concern for a large dam. Both Mulholland and Van Norman are convinced the new leak poses no threat, so they return to Los Angeles.

Ace Hopewell, a carpenter at Powerhouse No. 1, rides past the dam on his motorcycle. During the subsequent coroner's inquest, he states he rode up the canyon and passed both Powerhouse No. 2 (a hydroelectric power plant) and the dam without seeing anything to cause him concern. Approximately one mile (1.6 km) upstream from the dam he hears, above the sound of his motorcycle, a noise he describes as "rocks rolling down the mountain." He stops and dismounts from his motorcycle, leaving the engine idling, and smokes a cigarette while checking the hillside above him. He can still hear the sound that caught his attention earlier, although it is now fainter and behind him. Assuming it was a landslide, since they were common to the area, and satisfied he is in no danger, he continues on his way. He is probably the last person to see the St. Francis Dam intact.

The St. Francis Dam collapses, beginning with a landslide of the water-saturated eastern abutment and exacerbated by the hydraulic uplift phenomenon of the inadequately constructed base of the dam (see below), with eventual failure of the dam's western abutment, as well. The time of 11:57:30 p.m. is pinned to the fact that personnel of the Bureau of Water Works and Supply at both receiving stations in Los Angeles and at Powerhouse No. 1 note a sharp drop in voltage on their lines at that time. Simultaneously, a transformer at Southern California Edison's Saugus substation (on today's Magic Mountain Parkway) explodes. The transformer is connected to Edison's Antelope Valley Borel power line, running up the western hillside of the canyon near the dam to poles located about 90 feet above the eastern abutment. The prevailing theory is that this line is severed as the eastern hillside and abutment give way. The grounded lines cause a short, which in turn cause the transformer to explode.

Harnischfeger and his family are most likely among the first casualties caught in the flood wave, which is about 140 feet high (43 m) when it hits their cottage, approximately one-quarter mile (400 m) downstream from the dam. The body of Leona Johnson (often mistakenly reported afterward as Harnischfeger's wife) would be found fully clothed and wedged between two blocks of concrete near the base of the dam. This leads to the notion she and the damkeeper might have been inspecting the dam immediately before its failure. Neither Tony Harnischfeger's body nor that of his 6-year-old son, Coder, would be recovered.

Five minutes after the collapse, having traveled 1-1/2 miles (2.4 km) at an average speed of 18 mph (29 km/h), the now-120-foot-high (37 m) flood wave destroys the heavy concrete Powerhouse No. 2 — leaving only two turbines — and claims the lives of 64 of the 67 workmen and their family members who lived nearby. Lyman and Lillian Curtis notice a strange mist in the air and conclude the dam has collapsed. Lillian, her son Danny and the family dog head for high ground while husband Lyman goes back into the house to gather daughters Marjorie and Mazie. Only Lillian and Danny survive. Ray Rising, a utility man from the powerhouse, also is awakened and faces a 10-story-high wall of water. Swept into the floodwaters, he manages to climb onto a floating rooftop, which transports him to safety. He is the only other survivor at this power plant.

San Francisquito Canyon is ravaged. Six members of the Ruiz family are killed in the flood. At the base of the canyon, in present-day Tesoro del Valle, the water roars through and destroys part of actor Harry Carey's ranch, including a Navajo trading post, which had been a popular tourist attraction. Carey is away on business in New York. Legend has it, a group of Navajo Indians hired by Carey to work at the trading post had called Carey the night before the dam break, asking to leave the ranch for Arizona — based on a medicine man's premonition of an impending rupture. But according to Carey's son, Harry Carey Jr., the Indians actually asked Carey one month prior if they could leave when they did — after the medicine man went deer hunting near the dam and noticed a big crack in its face.

The deluge, now 55 feet high (17 m), continues, generally following the westward course of the river.It hits and demolishes Edison's Saugus substation, leaving the entire Santa Clara River Valley and parts of Ventura and Oxnard without power. At least four miles of the state's main north-south highway (now Interstate 5) are under water, and a short distance away, near the present-day Magic Mountain amusement park, the flood is washing away the town at Castaic Junction. Raymond Starbard, an assistant Edison patrolman at the Saugus substation, is nearly washed away; he hitches a ride to Wood's Garage next to the Saugus Cafe. There, Starbard places a call to Sheriff's Substation No. 6 in Newhall; he's credited with being the first person to sound the alarm about the flood.

150 Edison linemen are fast asleep in their tents at Kemp, a temporary camp near a railroad siding just east of the Los Angeles-Ventura county line. Night watchman Ed Locke watches in horror as a huge flood of water approaches the camp at 12 mph (19 km/h). Locke runs through the camp, waking as many people as possible. But the water hits a geological outcropping called Blue Cut and doubles back on the camp, creating a whirlpool that uproots the tents. Most of the workers who survive had zipped up their tents, allowing them to float on the whirlpool. Eighty-four of their fellow workers perish on this night, along with Locke — a true hero of the disaster.

Telephone operators Louise Gipe in Santa Paula and Reicel Jones in Saticoy — subsequently nicknamed the "Hello Girls" — bravely stay at their posts and begin systematically calling residents in low-lying areas, urging them to flee to higher ground. Gipe is at her station when, shortly before 1:30 a.m., she receives a message from the chief operator of the Pacific Long Distance Telephone Co. saying the St. Francis Dam has broken and a tremendous wall of water is sweeping down the valley. She receives orders to notify the authorities and then warn those in the coming floodpath. She immediately calls California Highway Patrol officer Thornton Edwards, who lives in Santa Paula, and then starts calling the homes of those in danger. Edwards is soon joined by another officer, Stanley Baker, and the two use their motorcycles to awaken and warn residents by leaving their sirens running and criss-crossing the streets in the danger zone. Whenever a resident comes out to investigate the commotion, the officers stop, give orders to evacuate, and instruct the citizen to pass along the warning. Edwards and the Baker ride for more than an hour through the lower sections of Santa Paula. The streets, initially crowded with people, are now mostly empty. Little more can be done in Santa Paula, although ranches and dairies in lowlands west of town might not have gotten the message. Edwards and Baker cover all territory accessible by motorcycle, warning those who have not received a telephone call. Taking different routes, the two head back to town. Sirens scream, alarms sound and many residents are saved as they rush to the hills only to watch their homes get crushed below them. For his wild yet courageous ride, Edwards is remembered as the Paul Revere of Santa Paula. In 2003 a statue would be erected in Santa Paula in Edwards' and Baker's honor.

The phone rings at the Mulholland residence. The Chief's daughter answers and wakes her father with the terrible news. As he lurches for the phone, he repeated the mantra over and over: "Please, God, don't let people be killed. Please, God, don't let people be killed." Mullholland would issue the following statement: "I would not venture at this time to express a positive opinion as to the cause of the St. Francis Dam disaster. ... Mr. Van Norman and I arrived at the scene of the break around 2:30 a.m. this morning. We saw at once that the dam was completely out and that the torrential flood of water from the reservoir had left an appalling record of death and destruction in the valley below."

Having devastated much of Santa Paula and heavily damaging the towns of Fillmore and Bardsdale, the floodwaters empty into the Pacific Ocean near Ventura at Montalvo, washing victims and debris out to sea. It had taken 5 hours and 27 minutes to travel 54 miles (87 km) from the dam site to the ocean. As it reaches the coast, the flood is nearly two miles wide (3 km), traveling at 6 mph (9.7 km/h). Bodies of victims would be recovered from the Pacific Ocean, some as far south as the Mexican border, while others are never found.

:The Los Angeles Times: "FOUR INQUIRIES UNDER WAY IN VALLEY DAM DISASTER." Immediately following the dam break, as many as eight agencies — city, county, state and federal — begin investigating the cause of the disaster. Most significant is the two-week coroner's inquest led by the ambitious Los Angeles District Attorney Asa Keyes. Keyes and the coroner's jury relentlessly question Mulholland about the composition of the concrete, the selection of the dam site on an earthquake fault, the construction and drainage of the dam's foundation, the anchoring of the dam to the walls of the canyon, and Mulholland's unquestioned role in supervising the dam construction. Keyes accuses Mulholland of ignoring reported leaks in the dam, days prior to the failure. Asked by Keyes if he would build the dam on the same spot again, Mulholland replies: "No, I must be frank and say that now I would not." Keyes presses on, asking Mulholland why not. The reply: "It failed, that's why. There is a hoodoo on it. ... It is vulnerable against human aggression, and I would not build it there." Mulholland suspected the dam had been dynamited by an Owens Valley conspiracy ring to avenge its construction. Toward the end of his testimony, Mulholland humbly states: "Don't blame anybody else, you just fasten it on me. If there is an error of human judgment, I was the human."

At the conclusion of the inquest, the coroner's jury finds: "The destruction of this dam was caused by the failure of the rock formations upon which it was built, and not by any error in the design of the dam itself or defect in the materials on which the dam was constructed." Although jurors express ambivalence about the inciting event leading to the collapse, they feel the preponderance of evidence favors an initial failure on the dam's western abutment, which was anchored to a type of rock called red Sespe conglomerate. During the inquest, Keyes demonstrates how this rock disintegrates when exposed to water. Jurors place the blame squarely on the shoulders of Mulholland and his Bureau of Water Works and Supply. They further attack the unquestioning trust in Mulholland's expertise. The final jury statement makes national headlines: "The construction of a municipal dam should never be left to the sole judgment of one man, no matter how eminent."

Mulholland takes full responsibility for the worst U.S. civil engineering failure of the 20th century and resigns his office. During the coroner's inquest he had said, "The only people I envy in this whole thing are the dead."

The Department of Public Works, under the administrative oversight of the State Engineer — later assumed by the Division of Safety of Dams — is authorized to review all non-federal dams over 25 feet high or which would hold more than 50 acre-feet of water (1 acre-foot of water is 325,851 gallons). The new legislation allows the state to employ consultants as necessary, and the state has full authority to supervise the maintenance and operation of non-federal dams.

Eaton dies — coincidentally, on the anniversary of the dam failure. In the end, Eaton's desire to enrich himself drives a wedge between himself and Mulholland, whose desire above all else was simply to build. They break off all contact when Eaton sets a price of $1 million for a piece of land needed for a storage reservoir dam; Mulholland considers Eaton's demand extortion. The deadlock ultimately destroys both men. While holding out to sell the dam site at his price, Eaton's finances crumble, and in 1928 they collapse altogether with the failure of the Owens Bank.

Mulholland dies in his home. His assistant, Harvey Van Norman, had succeeded him as chief engineer and general manager upon Mulholland's retirement. Mulholland had been retained as Chief Consulting Engineer with an office, receiving a salary of $500 a month. In later years, he goes into self-imposed semi-isolation. Shortly before his death at age 79, he consults on the Hoover Dam and Colorado River Aqueduct projects. In Los Angeles, where transgressions are quickly forgotten and celluloid heroes are made, Mulholland is revered as the superstar who brought L.A. the water it needed to grow into a major, world-class metropolis. The Mulholland Dam in the Hollywood Hills, Mulholland Drive, Mulholland Highway and the William Mulholland Memorial Fountain at Los Feliz are named in his honor