Commission approves channel renovation

City planners kept the momentum going at the May 25 meeting on a project to prevent the Laguna Canyon Channel from flooding upstream from Main Beach.

The Planning Commission signed off on the channel’s rehabilitation from the outlet at Main Beach to Beach Street, although the project is not scheduled to begin until after Labor Day 2012.

“We asked why they came to us so early, and they expressed concern that if the project were delayed for any reason, the agencies might reconsider their approvals,” Commissioner Norm Grossman said.

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.

The proposed project is on a much smaller scale than the $9-million one approved for funding and construction by the Army Corps of Engineers nine years ago, in which the city was to partner with the Orange County Flood Control District, which the council voted against 4 to 1 in 2002.

Funding for the city’s $900,000 project was approved in the 2008-09 budget and has been carried over.

The Laguna Canyon Channel drains from the watersheds in Laguna Canyon and others outside the city limits. It runs above and below ground and is under the jurisdiction of different agencies, including the city, the Orange County Flood Control District and several private property owners from El Toro Road to about City Hall and continues through downtown to Main Beach.

Environmental impacts have been reviewed and mitigation measures approved by the California Department of Fish and Game, the San Diego Regional Water Quality Control Board and the California Coastal Commission.

Laguna Canyon Flood Mitigation Task Force Committee recommendations will be included, said Grossman, a committee member.

“The commission did add a caveat to our approval that if any changes were made, the project would be brought back to us for review,” Grossman said.

The commission approval of the design is appealable to the City Council. The project scope and coastal development permit are appealable to the Coastal Commission.