Sewer construction to close North Gate Road in mid-June

OCTA

The Orange County Transportation Authority (OCTA) is scheduled to fully close North Gate Road as early as June 13 to build a new 18-inch sewer line that crosses the 405 from North Gate Road to Old Ranch Parkway. The schedule is subject to change due to inclement weather or other unforeseen circumstances. Work is expected to be completed in eight-to-12 weeks.

The I-405 Improvement Project team will host an online meeting to provide the community with an update on the North Gate Road construction. The meeting is scheduled from 4-5 p.m. on Thursday, June 9. People can register online at bit. ly/405webinar-northgateroad.

This will be the second time North Gate Road has been closed for a lengthy period and the third attempt to build the sewer line, according to OCTA and Seal Beach officials. The first subcontractor was unable to bore the new line through freeway subbase. Subbase is a layer of aggragate material to protect pavement and improve the application of subsequent pavement layers.

After more soil tests and hiring a second subcontractor, the crew was able to bore the line through the freeway subbase at Old Ranch Parkway to North Gate Road. A new manhole was built on North Gate Road, which was then repaved and opened to traffic in June 2021. The road was closed for 14 months.

The contractor subsequently attempted to connect the new manhole on Old Ranch Parkway and found that neccesary elevations and slope required for proper flow were not met. That sewer line cannot be used and will be abandoned, according to OCTA officials and Seal Beach City Engineer David Spitz.

Engineers have now redesigned an entirely new line to cross the freeway. OCTA recently approved a complete realignment and is ready to begin construction June 13, when North Gate Road will again be closed. The work entails installing a temporary sewer bypass system, excavating the bore receiving pit about 30 feet away from the last pit on North Gate Road and structurally supporting it. A bore receiving pit is used to remove the equipment and spoil—which is a slurry of soil and broken rock fragments resulting from the drilling process—from the tunnel when the bore is complete.

A manhole will be built to tie in the new line. The old manholes— one built in the 1960s and the other in 2021—will be abandoned. After tying in the new line, crews will backfill and pave North Gate Road. The road should be open by Labor Day Weekend.

For more information about the project, residents may contact the 405 project team at 405project@octa.net or (888) 400-8994.

—Ruth Osborn, managing editor