City Begins to Tackle Downtown Flooding

0
2071
Broadway Avenue drains onto Main Beach.
Broadway Avenue drains onto Main Beach. Photo by Ted Reckas.

This article was updated Jan. 28 after the print edition had been finalized.

Five years after a damaging flood and with predictions of a wet winter still to come, the City Council approved the first step Tuesday to improve the downtown storm control channel and increase capacity at a bottleneck renowned for flooding.

The Laguna Canyon Channel improvement project from Beach Street to the ocean is anticipated to cost $4.2 million. The 88-year-old channel will be cleaned out, patched up and restored to increase capacity up to 35 percent, bolstering its usefulness another 50 years, according to a staff report.

However, construction won’t start immediately, said the city’s acting Director of Public Works, Steve May, even though severe rainstorms are forecasted from a still-strong El Nino weather cycle.

To get the project’s design and permit process started, the council gave the go-ahead to hire Anderson Penna Partners, Inc., from Newport Beach, for $208,475 to oversee the project for a maximum of 19 months. The project management consultant will be paid from the $2.2 million currently budgeted for this segment of the channel improvement project. Another $2 million will be set aside to complete the project, the report stated.

No start time has been scheduled for the downtown portion of the channel improvement project, said May, which is expected to take about three years.

“We want to hire a project manager to ramrod this thing through the project phase,” he said at Tuesday’s meeting. The approval process for improvements is lengthy, requiring input and consent from outside entities such as the California Coastal Commission, Caltrans and the County of Orange, he said.

“Last time we talked about this, I was under the impression that we were going forward,” responded council member Toni Iseman. “I was surprised that we hadn’t.”

There was a plan for downtown channel improvements five years ago that was postponed, in part, due to construction of the lifeguard headquarters at Main Beach and the potential compounded congestion both projects would cause, said May. Other delays were caused by obtaining required permits and coordinating with various agencies that own different sections of the channel.

“The project wasn’t moving along fast enough with city staff so that is why we recommended that a project manager get involved,” City Manager John Pietig said Wednesday. “Given its complexity and importance, we want to make sure that it moves forward.”

The city’s last flood in 2010, a 100-year storm, sent torrents of water into downtown from Laguna Canyon that resulted in more than $13 million in damages. City officials estimate public property damage exceeding $7.7 million and 115 private property owners sustained another $5.8 million in damages, according to local Ann Quilter, who organized flood relief.

Since then, the city has undertaken several less costly flood-control steps to prepare for winter storms. These include installing a system of rain gauges that transmit real-time data, web cameras for stream monitoring, hillside soil-saturation monitors and a hydraulic study, the staff report notes. Notices on how to prepare for flooding were sent to residents and business owners in the canyon and downtown. And a new permit requirement makes the use of flood gates mandatory for properties in the floodplain or when the city issues a flood warning.

The downtown channel project addresses two problem culverts along the Beach Street-to-ocean flood channel segment, according to the staff report. The box culvert under Beach Street near Broadway Street can currently carry 800 cubic feet of water per second, but the segment that feeds into it from Laguna Canyon can carry far more at 2,200 cubic feet of water per second, said May.

When the December 2010 deluge overtaxed the channel’s capacity, a 15-foot geyser erupted at Beach Street, pouring tons of water onto downtown streets, according to reports. The new plan calls for eliminating a middle wall of the double-box culvert design, increasing the culvert’s capacity 35 percent, the report says.

A 50-foot portion of the 1928 flood channel segment upstream of Beach Street, managed by the county, will be also modified to streamline the flow into the culvert there.

A second box culvert under Coast Highway near Main Beach is only 4.5-feet high, called a “squash” box, and twice as wide as the upstream box culvert connecting to it, according to the report. A dumpster and even a Volkswagen got “squashed” there during previous floods, said May.

“When that kind of thing happens,” said May, “it reduces capacity significantly, as you can imagine, unless the windows are open in the Volkswagen.”

Caltrans, which governs Coast Highway, will contribute $1.4 million to stretch the squash box, requiring reconstructing 140 feet of the city channel from Coast Highway to the ocean outlet at Main Beach to match the new shape.

And that will impede traffic on Coast Highway for months, with vehicles detouring through downtown. The cost of the project is likely to double the Caltrans grant, said May. Other ways to prevent large objects from getting that far are possible at a lower cost with fewer traffic woes, he said. Because Caltrans is contributing money, Iseman said she supported proceeding with the Coast Highway portion of the project.

“Volkswagen aside,” Pietig said he wasn’t sure about spending that much money and disrupting that much traffic on Coast Highway.

The last 50 feet of the box culvert at Main Beach, where concrete has all but vanished, will also be replaced, according to the report, and other portions of the existing channel will be patched. The recommendation to hire an outside consultant was made to free city staff to work on other projects, according to the report.

“We hire consultants to manage our projects all the time,” May said earlier Tuesday. “They bring a whole list of other resources with them. They can do what needs to be done more quickly than we can with staff.”

Only two management teams made proposals. Firms that declined stated a preference to work on the final design of the project, which is more costly, the staff report stated.

Flooding is nothing new to Laguna Beach and isn’t going away, experts say. Despite the warm, sunny weather this week, El Nino storms are on track, according to National Oceanic and Atmospheric Administration, with February and March predicted as the wettest months. Warm-weather patches part of the cycle, NOAA reported. This El Nino is considered even stronger than the storms in January 1998, which were at the end of their run, according to NASA weather reports.

Share this:

LEAVE A REPLY

Please enter your comment!
Please enter your name here