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Santa Maria Sun / News
The following articles were printed from Santa Maria Sun [santamariasun.com] - Volume 14, Issue 47
Lompoc is still trying to secure funding to stabilize the Santa Ynez riverbank
BY CAMILLIA LANHAM
At the east end of Pine Avenue in Lompoc, the Santa Ynez River, a wooden fence, and a city sign greet bike path pedestrians.
“City Property, No Dumping, No Trespassing,” the sign reads.
On the other side of it, a wide path, flanked by pieces of trash, leads from the bike path down the side of the riverbank and into the riverbed. Footprints and tire tracks mark the river’s silt- and rock-covered bottom, but if you’re looking for water, you won’t find it there.
So it’s hard to believe that one gigantic storm, or a series of smaller storms, could wipe the bank out, endangering the homes on Riverside Drive between Pine and North avenues. But it could, and the city’s been trying since 2011 to fund a project that would stabilize that riverbank, as well as a portion of the bank next to River Bend Park.
The city of Lompoc might have just got the big funding break it needs, but only for one of the bank sites, and that money is contingent upon approval from the Federal Emergency Management Agency (FEMA).
“They have expressed interest, so it’s promising,” Craig Dierling, the city’s senior civil engineer, told the Sun.
The city submitted its original application through FEMA’s Hazard Mitigation Grant Program in 2012, which only covers 75 percent of project costs. The city is looking elsewhere to fund the remaining 25 percent. Lompoc estimated that stabilizing the bank at both sites would cost an estimated $2.7 million.
FEMA responded to the application by saying it would be willing to cover the stabilization of the southern portion of bank, but not the north. The southern-most project is along Riverside Drive, where homes are about 40 feet from the bank. Lompoc would need to reduce the scope of the grant application.
“They said that they would not support the northern portion at all,” Dierling said. “Because it wasn’t a near-term threat to life and safety, essentially.”
At the northern end of the river, all that would be lost in a catastrophic storm is recreation space and athletic fields, while along Riverside Drive, homes—and possibly lives—could be lost.
The Lompoc City Council voted unanimously, with councilors Ashley Costa and Bob Lingl absent, to reduce the scope of the grant application at its regular meeting on Jan. 21.
“This is a no-brainer: We get rid of the north and fix the south,” Councilmember Dirk Starbuck said during the meeting.
When Mayor John Linn added his two cents at the meeting, he said that when the project started, the city initially looked at the north end, near River Bend Park, as the problem to focus on and tacked the southern portion onto the project as an afterthought.
Dierling explained to the Sun that the reason the bank closest to homes wasn’t the project’s primary focus is because the erosion near the park is much more noticeable.
“When there are erosion losses, like 100 feet of bank goes away,” civil engineer Dierling said. “It’s harder to see damage at the southern location.”
Near all those Riverside Drive homes, the bank only erodes a few feet at a time, with no significantly visible losses. But the bank is nearly 30-feet vertical near the end of Cherry Avenue. A bike path and the road stand between houses and the river’s edge.
When the Santa Ynez River is flowing, it’s not like it runs 30 feet deep. But as it flows, water punches into sediment at the bottom of the bank, also known as the toe.
“The toe of the bank gets constantly scoured by river flows, and the toe goes away and the top of the bank falls,” Dierling said. “We noticed trees on the bank and other things that have visibly gone away during the 2011 spring flows.”
How then, does a bank become stable?
Dierling said metal pilings will be driven into the river’s bottom near the edge of the bank, and those pilings will stick out about 8 to 10 feet above the ground. Cables will then get strung between the pilings. The structure acts as a sort of net to catch trees and other debris as it floats down the river. As debris piles up, so will sediment.
It’s the sort of stabilization project that’s worked on the Santa Ynez River in Buellton and two different sites in Solvang.
“It doesn’t cause as much damage, and it uses the natural flow of the river,” Dierling said.
The overall project will cost about $900,000, but the grant’s not approved yet. Lompoc has notified FEMA that it’s planning to reduce the scope of the initial grant application, but FEMA still needs to approve the project. City staff is hoping to get the revised application in by March and hear back from FEMA by April.
Dierling added that it’s not easy to predict when a storm could come along and knock out the bank. The storm or storms needed are of the variety that come along once every 50 years.
“No one can really say, ‘Yeah, [the bank] will be gone in 25 years,’” he said. “They can only say that there’s a 25 percent chance of that happening.”
Contact Staff Writer Camillia Lanham at firstname.lastname@example.org.