![]() “ Like all water conveyance systems at Metropolitan and across the state, a water conveyance system has a higher standard of seismic performance than any regular structure or buildings under the modern building code,” he said. Lum then discussed each of these in detail. The seismic design of the tunnel is based on three criteria: water system reliability, Bay Area seismicity, and tunnel system performance. DWR performed preliminary ground exploration, and there were detailed evaluations of seismic parameters and site-specific geologic conditions that characterize what kind of ground motion and what kind of earthquakes we might have to deal with for the Delta tunnel alignment, he said. In the conceptual design phase, a lot of effort was put into the viability and feasibility of the tunnel options. ![]() The system we have for the Delta program is a one-pass system.” The state of the art portion of the process is the earth pressure balancing tunnel boring machine that’s ahead of the tunnel lining system that allows the tunnel boring machine to stabilize the ground as this advances. The front part of the tunnel boring machine is roughly about 10 to 15 meters long, and following that is the tunnel lining system which is made out of concrete segments. “ It essentially consists of a tunnel boring machine, or TBM, that moves ahead of the concrete segmental lining system. ![]() “ For the Delta tunnels concept, they’re proposing to stay at the practice as well as state of the art tunneling concept,” he explained. There’s been a lot of tunneling work conducted in the United States in the past century, and tunnel technology has evolved quite a bit during that time, said Mr. He noted the other options that were considered: the western alignment shown in blue consisting of 36 miles of canal and 17 miles of tunnel the eastern alignment in yellow, consisting primarily of canal embankments, and a thru-Delta option, shown in green and blue, which essentially separated corridors for fish and water conveyance. The green line on the map is the pipeline/tunnel option which consists entirely of tunnels and will be focus of today’s presentation, he said. Howard Lum then took the podium, and began by presenting a slide with the four options for alignment of the tunnel in the Delta. ![]() He’s published research on tunnel design extensively, and he’s also a professor at Cal State Los Angeles.” He has done multiple projects throughout the nation, and specifically in LA, he’s worked on the MTA Gold Line, he’s worked on our inland feeder arrowhead tunnels, he’s worked on Lake Mathews outlet facilities. “ Howard came to us about 20 years ago he worked for a premier tunnel design firm at that time. “ One of the strengths of Metropolitan is in its staff, and an example of that is Howard Lum,” said Randall Neudeck. Part 2 will cover the committee’s review of the BDCP’s Implementation Agreement, and will post on Wednesday.) ( Note: This is part one of two-part coverage. The presentation included details on the seismic design criteria and the construction of the tunnel and its lining system, as well as the historic seismic performance of tunnels. Meanwhile, Jeffrey Kightlinger, general manager of the Metropolitan Water District of Southern California, a state-established cooperative that supplies water to 19 million people in six counties, calls the plan “welcome progress” on a long-overdue upgrade to the state’s water delivery system.Īccording to the Water Resilience Portfolio, even a gradual rise in sea level will more more ocean saltwater into the San Francisco Bay/Sacramento-San Joaquin Delta and affect brackish and freshwater habitats.At the June 24th meeting of Metropolitan Water District’s Special Committee on the Bay Delta, committee members heard a presentation on the seismic performance for the proposed twin tunnels, the centerpiece of the Bay Delta Conservation Plan. “This project is crucial to ensuring the long-term reliability of this major water supply.” “For most of our members, it’s a cost-effective supply even as they invest to diversify their portfolios.”Ĭalifornia’s current conveyance system-which moves large portions of California’s surface water supply-faces major vulnerabilities including floods, subsidence, earthquakes and climate change, says Mellon. ![]() “Faced with the realities of more intense droughts and floods, the State Water Contractors have built local and regional projects to diversify and expand their water supplies, and they continue to explore new ways to serve their customers into the future,” Pierre said in a SWC statement. Jennifer Pierre, SWC general manager, said a Delta tunnel is a necessary solution for a reliable California water supply as climate change impacts increase. ![]()
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |