City Council members were briefed Tuesday on a plan to breach levees and dikes around two former Cargill salt ponds to allow Permanente Creek and Charleston Slough to flow in and out of them freely, speeding up their return to marsh lands. It is a process of "taking down berms and dikes and letting nature take over," said South Bay Salt Pond restoration project manager John Bourgeois.
To achieve that, levees and dikes around the former salt ponds would be breached in certain places adjacent to Permanente and Stevens Creek and Charleston Slough.
"We've been waiting 30 years for that marsh to develop and it's been doing it very slowly," said public works director Mike Fuller of the ponds and Charleston Slough, which feeds the Shoreline sailing lake.
The project would also replace levees along Shoreline Park's northern edge that provide some level of flood protection from the bay.
"These levees weren't even engineered to be flood protection," Bourgeois said. "As we take these down we want to make sure the nearby communities are safe."
Bourgeois said that SBSP is working with a "dirt broker" to put in the new engineered levees at no cost. It's an economical way to dispose of dirt excavated from nearby development projects, Bourgeois said.
"Improving those levees is one of the projects identified in our sea level rise project," said Fuller. "If we coordinate with the salt pond restoration project we have the opportunity to reduce the scope of that project for us. It could really be a win for the city."
Fuller added that "On the downside we've probably got 10,000 truckloads of dirt that have to come through the park," Fuller added. "We've hauled a lot of dirt out there, it's something we're used to doing."
The former salt ponds, known as A1 and A2W, are part of a larger project to restore 15,000 acres of former salt ponds in the South Bay obtained from Cargill in 2003, an area the size of Manhattan. An environmental report on the project is expected to come out in the first quarter of next year.