With a heavy El Niño in the forecast this winter, Sausalito will fast-track flood prevention measures along Gate 5 Road.
The public works department plans to beef up pumps at key drainage conduits in one of the city’s most flood-prone areas. Property owners at nearby Varda Landing also suggested raising a private road to create a levee to counter king tides.
“There may be some things that can be done via simple permitting,” Mayor Steven Woodside said Tuesday during a City Council flood control discussion.
“Yes, absolutely,” said Brandon Phipps, interim city manager. “We’d be happy to streamline those kinds of proposals to help bolster against Super El Niño.”
Earlier, county emergency management officials told the council that worrisome tides would crest on Thanksgiving, Christmas Eve and Christmas Day, and in late January.
The Gate 5 Road area is in the northeast corner of the Marinship district. It is a mix of maritime businesses, art studios and residences.
Record king tides last January flooded the area, overwhelmed city emergency pumps and filled many ground floors with several feet of water. The flooding came as city consultants were studying causes, scenarios and countermeasures for the area’s chronic flooding.
Consultant Eric Slaugh of WSP USA told the council that the bay is expected to rise 6 feet by 2100 while the Marinship area subsides by another 3 to 4 feet. He described how hillside stormwater runoff, infrastructure, drainage systems, tidal flows, tidal surges and the rising sea interact to cause floods.
Slaugh suggested a mix of complementary short- and long-term solutions. By the shoreline, he suggested tidal gates, pumps for drainage systems and eventually a seawall. Uphill and farther inland, he suggested landscaping that absorbs stormwater and water storage facilities under parks. Each of the projects could cost millions of dollars.
As an immediate task, he suggested installing a tidal gate and large pumping station above the Coloma Street drainage canal. The narrow channel with sheet-metal walls funnels runoff from west of Bridgeway to the bay. During king tides, however, the drainage system works in reverse as pressure from cresting bay waters presses inward and spills out of storm drains.
“A gate that’s put on the outfall acts as a barrier so the water cannot go into the culvert,” Slaugh said. “And say we get a large rainfall … that pump station would kick on to get water around the gate.”
Since late last year, a temporary pumping system has been in place for the canal and nearby key drainage junctions. Since the king tides in January, it has prevented further flooding.
Kevin McGowan, the city public works director, said it is ready to solicit proposals to install a pumping system before this winter. The system would be smaller than WSP’s suggestion.
During public comments, property and business owners praised the city’s attentiveness after the winter floods, but said action is needed now.
Ken Pedersen, the owner of Clipper Yacht Harbor, and Reason Bradley, a property owner at Varda Landing, both said more could be done to supplement the city’s preparations.
They suggested raising a private road on their properties from the Clipper Yacht Harbor parking lot to Gate 5 Road to create a levee that would block another entry point for tidal surges.
“We’ve come up with a plan that’s pretty simple,” Bradley said. “This isn’t a 100-year plan. This is like a 20-year plan.”
“We’re just proposing a bunch of trucks of dirt, raise the road a little bit, a couple of pumps, and then put in some check valves,” he said, estimating its cost at $100,000.
“I want to back up and thank public works,” said Dan Morgan, a landlord who has lost tenants because of flooding. “Since the temporary pumps went in and the outfall got shut off, that has worked.”
“That system that’s temporary now will continue working until the overland flows at Varda Landing inundate Gate 5,” he said. “Then the pumps get turned off because you can’t stay ahead of it.”
“We are motivated to do what we can to address this,” Woodside said, suggesting that the city could tap its reserve funds if necessary.
“I agree with my fellow council members that immediate action is required,” Councilmember Joan Cox said. “I would endorse utilizing our emergency fund if we don’t have funds elsewhere.”