Environment & Science

Newport's Balboa Island plans to raise seawalls to fend off rising tides

Newport Beach workers pump water that overtopped the seawalls on Balboa Island on Dec. 22, 2010. High tides and storm surges occasionally cause flooding on the island, but sea level rise threatens to make it a more frequent phenomenon. The city plans to extend the island's seawalls by 9 inches as a short-term fix.
Newport Beach workers pump water that overtopped the seawalls on Balboa Island on Dec. 22, 2010. High tides and storm surges occasionally cause flooding on the island, but sea level rise threatens to make it a more frequent phenomenon. The city plans to extend the island's seawalls by 9 inches as a short-term fix.
Courtesy: City of Newport Beach

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Newport Beach’s historic Balboa Island is soon to get a minor facelift to prepare for rising sea levels. The roughly 8-foot seawalls that circle Balboa Island’s 1.7-mile perimeter offer fantastic views of Newport Harbor from the adjacent boardwalk. 

But at that height — among the lowest in flood-prone coastal areas in Southern California — they'll be no match for rising sea levels, if current projections hold. 

To prepare for rising tides and to combat the occasional flooding the island already faces, the city of Newport Beach plans to build up the existing seawalls another 9 inches, giving them a height of 8.5 to 9 feet. It’s a short-term fix, the city admits. 

“This gets us by for the next 10 to 20 years," said City Engineer Mark Vukojevic.

Last year, city staff presented four options to the Newport Beach City Council for shoring up the island’s flood protection, including replacing the nearly 80- to 90-year-old seawalls with 10-foot-high walls that could be extended to 14 feet in the future.

The estimated cost would have been $68 million.

The council opted instead for the cheapest and shortest-term option, extending the existing seawalls. The work is expected to cost $1.5 to $2 million, according to a staff report

City council will vote Tuesday to put the project out to bid, with work expected to begin this fall. 

The California Coastal Commission recommends planning for seas to rise by as much as 66 inches by 2100.

Vukojevic said the city’s strategy for Balboa Island is to adapt to change incrementally. 

“We want to make sure we balance it just right for flood protection and public impacts and public views,” he said. 

Balboa Island's seawalls will likely need to be replaced within the next two decades, he said.