Staff requested the hearing to avoid losing momentum, City Engineer Steve May said.
"We wanted to finalize the environmental document and the design plans while the design team was up to speed," he said.
As approved, the project includes the demolition and reconstruction of the underground box channel from Main Beach to the ocean side of South Coast Highway, and less extensive repairs to the reach from the inland side of the highway to Beach Street.
City staff considers the concrete-reinforced structure under Main Beach to be at or near failure in some locations.
The rehabilitation will include the temporary removal of the Main Beach Plaza seating area, a portion of the boardwalk landscaping and planter areas, and some portions of the park sidewalk to access the underground channel, which lies about two feet below grade. Nine new support pilings will be installed, and 20 now in place will remain, according to a staff report.
No construction is proposed for the channel under the highway, which is under the California Department of Transportation's jurisdiction, Grossman said.
On the other side of the highway, ending at the channel intersection with the Beach Street right-of-way, unsound concrete will be removed and replaced, and exposed rebar will be repaired or replaced. Grease, dust and other foreign materials will be removed and the surface of the box channel cleaned.
The project will not reduce potential flooding downtown, May said. Flooding, like what happened in December, is the result of more water from upstream than the channel can handle from Beach Street to Main Beach.
"We will be looking at options over the next year to see if there is a feasible solution to the problem, as well as programs to help us live with the situation," May said.