Broomfield, Colo., September 29, 2011 – MWH announced today that their work on the seismic and hydraulic rehabilitation of Big Tujunga Dam has been awarded the National Rehabilitation Project of the Year Award by the Association of State Dam Safety Officials (ASDSO). The award recognizes a unique remedial design that advances state-of-the-art in the field of dam safety and exemplifies the high professional engineering standards that dam safety requires.
The 244-foot-tall Big Tujunga Dam, located in the San Gabriel Mountains just north of the City of Los Angeles, has been challenged by seismic and hydraulic concerns for more than 30 years. The rehabilitation project addressed concerns the structure could fail under a significant seismic or flooding event, which would likely have resulted in injury and/or loss of life; $175 million in damages to property and infrastructure; more than 100,000 people experiencing disruptions to utilities, services and commerce; and loss of water storage and supply for the City of Los Angeles.
“We are honored to be recognized for our outstanding work in the field of dam rehabilitation by ASDSO,” says Glenn Tarbox, dams practice leader for MWH. “This project exemplifies a commitment to dam safety by our client, the Los Angeles County Department of Public Works, and exemplary innovation by our team of dam engineering experts.”
The Los Angeles County Department of Public Works (LACDPW) commissioned MWH to study and analyze seismic and hydraulic issues related to the dam, which confirmed the dam’s inability to handle Maximum Credible Earthquake and Probable Maximum Flood events. 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.
Prior to rehabilitation, the reservoir was operating at 25 percent storage capacity due to safety concerns for more than 30 years. Restoring the reservoir to original capacity through the rehabilitation project has also led to increased water storage for the City of Los Angeles, saving nearly $2 million per year in otherwise imported water costs.
The rehabilitation project, which began in 2008, was completed in July 2011. The award was presented on Sept. 28, 2011 at the ASDSO Dam Safety 2011 National Conference in Washington, D.C.
MWH, globally driving the wet infrastructure sector, is leading the world in results-oriented management services, technical engineering, construction services and solutions to create a better world. The wet infrastructure sector encompasses a full range of water related projects and programs from water supply, treatment and storage, dams, water management for the natural resources industry and coastal restoration to renewable power and environmental services. MWH is a private, employee-owned engineering consultancy with offices in 34 countries on six continents – including an Anchorage office for the past 30 years. For more information visit the Web site at www.mwhglobal.com