The dam was built to serve the growing water needs of the city of Los Angeles, creating a large regulating and storage reservoir that was an integral part of the Los Angeles Aqueduct. It was located in San Francisquito Canyon of the Sierra Pelona Mountains, about 40 miles (64 km) northwest of downtown Los Angeles, and approximately 10 miles (16 km) north of the present day city of Santa Clarita.
However, a defective soil foundation and design flaws led to the dam's collapse just two years after its completion. Its failure ended the career of William Mulholland, the general manager and chief engineer of the Bureau of Water Works and Supply (now the Los Angeles Department of Water and Power).[7]
IIRC Mulholland was not an engineer and some grievous engineering errors had been made on that project.
An older relative worked on the John Hancock Building and I heard ALL about it. Interesting stuff!
Short version:
August 24, 1966 – Developers of the 100-story John Hancock Center at Michigan Avenue and Delaware Place announce that they have ordered a second round of tests for 57 caissons, a portion of the caissons that will form the foundation of the building. The action comes after voids and imperfections are found in five of those caissons, starting about 60 feet below ground level. Engineers predict that testing and repairs will continue for three weeks. Construction on the super-tall building was halted on August 5 when a caisson moved sideways after a 12-ton test beam was placed on top of it. J. Theodor Dailey, a co-developer on the project, says, “Such a review is necessary because of the unique design of the building, its foundation, and soil conditions at the site. When approved, the foundation will have undergone one of the most complete analysis in construction history.” [Chicago Tribune, August 25, 1966]. The problems originated with the steel tubes that were used to hold back soil and water as the caisson holes were excavated. These tubes were removed as concrete was poured, which resulted in concrete being pulled up with the tubes in some caisson holes, allowing voids to form which filled with soil or water. Over two-dozen of the caisson holes required corrective work, adding six months to the construction schedule and another $1 million to the budget. It is fortunate, though, that the problems were discovered and corrected. Considering what might have happened if the problems were not detected, the Engineering News-Record opined, “Cost in dollars or in lives from damage that might have befallen a completed 100-story John Hancock Center if its faulty caissons had settled years hence is just too horrible to dwell upon.” [Chicago Tribune, March 24, 1985]
Prior to the Soviets successful launch of Sputnik, engineering in the US was an applied science and engineers were apprenticed to gain knowledge and skill. Mulholland was self-taught, but learning water runs downhill through canals is a far cry from designing a dam structure.
He should have trusted others to design and build the dam, but his ego got the better of him