More than a dozen people piled into a shuttle Saturday morning to see for themselves progress on the West Feather River levee work.
The bulldozers were still but residents could see the recently-backfilled trench covering a 3-foot-wide tool protecting hundreds of thousands of people from flooding: the slurry wall.
The Sutter Butte Flood Control Agency got to work on emergency levee repairs following last winter’s high waters and the Oroville Dam evacuation. Seepage, boils, sink holes and water erosion were signs of severe distress. The $28.5 million project, mostly funded by the state, is geared up to complete by Christmas.
“We don’t like having to fix levees in the middle of flood season – and we’re in flood season – but that’s the way the timing worked out,” Mike Inamine, executive director of SBFCA, told residents ahead of the tour Saturday.
In the Levee District 1 office, a powerpoint presentation broke down some of the basics in repairing and reinforcing levees. The slurry wall is the primary method used to combat deep under-seepage and through seepage. The walls, made of bentonite clay, water, and surrounding soils, are 3 feet wide and can be as deep as 110 feet.
The bus first took residents atop the levee on Second Street near Whiteaker Hall in Yuba City.
Workers have been excavating the slurry wall trench while simultaneously backfilling it with the clay, water and soil mixture. The wall reaches depths of up to 85 feet – deep enough so that the wall can settle into an impervious layer of soil.
There’s one area south of the boat ramp that awaits completion but the rest of the levee is at or above the 200-year water surface elevation.
Contractors hope to get to work reconstructing the top of the levee Monday. Paving of the top of the levee could happen on an upcoming clear winter day, but Director of Engineering Michael Bessette said it likely won’t occur until spring.
Next, the bus shuttled residents to Teagarden Avenue between the 10th and Fifth Street bridges, where hydroseeding (grass) has been freshly laid.
“It’s hard to appreciate unless you’re standing on top of the levee in high water, how high the water can get,” Inamine said.
He told residents that the water surface elevation during the 1997 flood was 10 eet higher than last year’s high water event.
“And yet, during this event we saw the distress much like in the 1997 event,” Inamine said. “That’s what made it very concerning to us.”
Linda and David Maas said the tour Saturday was informative. The couple has been trying to stay updated on the levee work, as it’s a critical issue.
“It’s comforting to know that it’s going to be in better shape than this past winter,” Linda Maas said. “It’s just a reminder that we do live in an area that floods. It’s only as strong as its weakest link.”