The 244-foot-tall Big Tujunga Dam, nestled in the San Gabriel Mountains northeast of Los Angeles, Cali., was originally completed in 1931. MWH worked with the Los Angeles County Department of Public Works (LACDPW) to perform rehabilitation and spillway modification to help meet the updated standards for Maximum Credible Earthquake (MCE) and Probable Maximum Flood (PMF) scenarios.
LACDPW commissioned MWH to conduct studies to re-analyze both the seismic and hydraulic issues related to the dam, which was operating at 25 percent storage capacity due to seismic safety concerns for more than 30 years. The studies confirmed the dam’s inability to handle MCE and PMF, and proposed a number of alternatives for both the seismic and hydraulic rehabilitation.
MWH proposed a number of alternatives for both the seismic and hydraulic rehabilitation. Ultimately, LACDPW selected the alternative design recommended by MWH to strengthen the dam by adding concrete against the downstream side of the dam to create a “thick arch” in combination with construction of a new ogee crest spillway with flip-bucket. MWH provided optimized and efficient design solutions for the rehabilitation of both the dam and spillway, and provided engineering services during construction.
Construction began in early 2008, with the last concrete block placed in January 2011, and the project re-dedicated on July 21, 2011.
Seismic and Hydraulic Studies and Analysis
Optimized and Efficient Design Solutions
Geotechnical engineering services
Structural engineering services
Hydraulic engineering services
Mechanical and electrical engineering services
Engineering Services During Construction
2012 Award of Excellence in the Constructed Project from the United States Society on Dams
2012 Public Works Project of the Year for projects over $75 million from the American Public Works Association
Named 2011 Best Civil Works/Infrastructure Project in California by Engineering News-Record