DVIDS – News – Engineers from Los Angeles and Philadelphia perform hydraulic steel structure inspection at Sepulveda Dam

VAN NUYS, Calif. – Engineers from the Los Angeles and Philadelphia Districts of the U.S. Army Corps of Engineers performed a periodic inspection of the steel hydraulic structure of the Sepulveda Dam March 22-23 in Van Nuys.

The dam on the Los Angele River is a massive concrete structure, easily visible from two major freeways, and has been used as a filming location for many movies. To perform the inspection, structural engineers Robert Lawrence and Joseph Cervantes, both of Philadelphia, ventured deep into its cavernous rooms of hydraulic equipment with the LA District team.

Seven submersible weir crests — drum, gates and vertical lift gates — were visually inspected, said LA District Civil Engineer Gabby Bernaldino.

“Crest gates are designed to float on water in a chamber, located inside the weir crest,” she said. “They operate automatically and rise as the elevation of the water surface of the reservoir increases. The gates are set for fully automatic operations, but (they) can also be operated in manual semi-automatic or manual mode. emergency.

The purpose of the inspection was to detect any potential damage, deterioration or signs of distress within the structure and to identify any need for maintenance repairs.

Inspections are carried out in accordance with Corps regulations to ensure that the dam’s critical internal infrastructure – the structural elements that could render it inoperable – are fit for service. It is best to carry out inspections when there is no water, in accordance with technical regulations. Upon inspection, the LA River at Van Nuys was very shallow.

“The inspection procedure was designed to detect damage, deterioration or signs of distress to prevent premature structural failure and identify any future maintenance or repairs,” Bernaldino said.

Prior to the inspection, LA District personnel received confined space training. Before anyone entered the structure, heavy steel plates and matching joints above the dam were removed from deep ventilation shafts that descend to a tunnel running the length of the dam. Ventilation pipes like those used by firefighters were inserted to remove any toxic gas buildup, then the air quality was checked. After security protocol was completed, Corps personnel entered.

The entrance inside the Sepulveda Dam is a square concrete cube resembling a castle on top. Once inside, a series of long stairwells lead to the seven weir gates and the tunnel at the very bottom. Now 80 years old, the dam contains a mix of old and modern equipment. Time-yellowed schematics used during construction hang on the walls, along with an old intercom system, while modern LED lighting provides illumination. In some places, daylight can be seen through heavy railings above the Los Angeles River.

The Corps acquired more than 2,100 acres of land for the construction, operation and maintenance of the Sepulveda Dam, which was built in response to the historic 1938 Los Angeles flood. The dam was completed in December 1941 and dedicated in 1942. It marks the beginning of the canalized LA River. Along with the Hansen and Lopez Dams, Sepulveda is vital to flood risk management for portions of the San Fernando Valley and areas contiguous to the LA River.

The primary purpose of the dam and reservoir is flood risk management, but the project is also licensed for recreational purposes.

Of the total area, the Corps reserves 313 acres of land for dam operations, and over 1,500 acres have been leased to the City of Los Angeles for recreational purposes.

Sepulveda Basin is a popular recreation area with a model airplane airport, softball courts and a Japanese garden. It is home to a variety of species and is an important nesting area for birds.