If heavy storms saturate the Arroyo Grande Creek channel this winter and threaten to overtop the banks of the northern levee, the southern side of the levee could be breached to protect homes and residents at the expense of prime farmland.
For the first time since the Arroyo Grande Creek channel was constructed in the late 1950s, San Luis Obispo County supervisors unanimously voted to authorize the southern creek levee in Oceano to be breached if failure of the northern levee is imminent.
“Overtopping could result in significant impacts to property and life,” said Dean Benedix, utilities division manager for county Public Works.
And, he added, it’s not a question of whether the levee will overtop — but when that will happen.
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Public Works officials are particularly concerned about this winter because the Lopez Lake reservoir is at 88 percent of its capacity, and sediment has built up over the years in the 3-mile-long flood-control channel, severely limiting its capacity.
A county engineering report in 1999 estimated that the channel had lost 85 percent of its capacity.
County officials are in the process of trying to get a permit through the U.S. Army Corps of Engineers that would allow them to remove some sediment from the channel and increase its capacity. They hope to have the permit by the spring, Benedix said.
In the meantime, crews have raised the north and south levees in an effort to prevent water from spilling over the Arroyo Grande Creek channel west of 22nd Street and the railroad crossing. The north levee is 4 to 6 inches higher than the south side.
The impact of floodwaters, if the southern side of the levee were breached, would likely be similar to what happened during spring floods of 2001. Then, a levee break flooded hundreds of acres of prime farmland and caused more than $1 million in damage.
Farmers would inevitably suffer deep losses again if their land is flooded.
“I can see why they’d say ‘flood the farmland,’ ” said farmer Tom Ikeda, who had up to 150 acres of cropland flooded in 2001. “It’s the lesser of two evils. But it’s something that I’m assuming we’re going to have to bear the cost of, and it’s not going to be our fault. As farmers, it’s our livelihood.”
If flooding happened in the spring, shortly after planting, Ikeda added, farmers would be almost assured of losing money for the year.
Public Works officials identified two possible locations for a breach: downstream of the Highway 1 bridge that crosses the creek next to Halycon Road, or west of the Creek Road intersection with the levee.
A levee breach would happen only after residents had been evacuated, a reverse 911 system had been activated, and a command team, comprised of county officials including the sheriff, Public Works and Public Health, had decided a break in the levee was necessary, said County Administrative Officer Jim Grant.
In the meantime, Public Works officials are also continuing to work on short-term fixes that supervisors had previously approved for an area of Oceano that was hit hard last winter by storms.
In one area, near the Oceano County Airport and South San Luis Obispo County Sanitation District, water from the Meadow Creek Lagoon (or Oceano Lagoon) flooded nearby homes, forcing some residents to evacuate.
Now, Public Works officials have proposed installing a pipeline along Juanita Avenue that would pump water from the lagoon to the beach before a large storm to increase the lagoon’s capacity.
They’re also hoping to remove some of the reeds from the lagoon, to improve the water flow, at an estimated cost of $30,000 to $45,000.
Local resident Joe Schacherer, who lives on Security Court and has been critical of the county’s response, said he was pleasantly surprised by the recent efforts.
But Greg Cobb, whose nearby home on Honolulu Avenue flooded last December, said he found the response lacking.
“Truthfully, there isn’t any plan in place to help us out this year,” he told supervisors. “There needs to be a long-term plan to get the lagoon dredged and put back to how it was.”