Did the Steel Curtains Help Montecito?

One of Six Steel Nets Filled with Debris

The ring net at upper San Ysidro Creek on Tuesday, January 10. | Credit: Courtesy John MacFarlane

[Updated: Jan. 19, 2023, 12:15 p.m.]

Success, like beauty, lies squarely in the eye of the beholder. In the case of the six steel nets strung across Montecito creeks designed to prevent another deadly debris flow, the answer will remain decidedly undecided for the time being. “I don’t know that we know,” said county supervisor Das Williams — whose district includes Montecito — of the steel nets’ impact during last week’s torrential downpours. “But it seems like it was somewhere between successful and very successful.”

What is known for certain, however, is that just one of the six steel nets — engineered to block the flow of runaway boulders careening down their respective creek channels from Camino Cielo — was filled to the top with rocks and debris after last week’s rains. The other five were not.

Had this material — trapped behind a net on the upper reaches of San Ysidro Creek — been allowed to continue its downhill trajectory, it would have encountered a second steel curtain farther downstream on the same creek. Had it broken free of that one too, the careening mass of boulders, mud, and debris would have likely been swallowed by the new Randall Road debris basin — with a holding capacity of about 95,000 cubic yards — just completed for exactly this purpose.

Were this massive flow able to overwhelm the new catch basin and keep moving downstream, it would likely make its way to Highway 101, thus blocking the north-south flow of one of the state’s most vital traffic arteries. 

That’s a lot of ifs.

Nets and Basins 

Back in 2018 at the time of Montecito’s deadly debris flow, none of the steel nets or the Randall Road basin were even being considered. Thus there was nothing stopping its lethal path on January 9, which killed 23 people, destroyed or damaged 500 structures, and blocked Highway 101 for weeks.

Hence the impetus behind both the steel nets and the new basin. 

Pushing for the construction of the new basin was the county’s Flood Control Department, the federal government’s Army Corps of Engineers, and a handful of Montecito residents willing to sell their properties for considerably less than what the market would bear.

Pushing for the installation of the steel curtains was a group of civic-minded Montecito residents who formed the private nonprofit, the Partnership for Resilient Communities, which raised nearly $6 million to make their dreams of steel netted safety become a reality. (Joe Cole, an investor in the Independent and former publisher, has been an active member of this partnership.)

When the recent rains subsided, the new Randall Road basin was roughly half full.

Of the six steel nets — two each on three creeks — only the one on upper San Ysidro Creek had  stopped a significant mass of stones and debris. It had been hit with sufficient  force to activate the net’s trigger mechanism, causing the trapezoidal-shaped net to expand outward to absorb the incoming force. Four of the six nets had nothing trapped behind them; water flowed clear and unimpeded through the space between the net bottoms and the top of San Ysidro creek.  One had trapped a small collection of rocks and debris. The other four experienced a significant scouring — on the magnitude of a few feet — of their respective creek channels.

It’s hard to say what exactly the sixth curtain caught. According to engineering geologist Larry Gurrola — working with the Partnership — the trails and slopes leading up to the upper San Ysidro net were too slippery to traverse. No direct observation, he said, has been possible. He was forced to rely on video footage shot by drones instead. Based on that footage, shot from a distance, Gurrola characterized the upper San Ysidro net as being “full of debris,” adding that the “creek flow cascaded over and seeped through the net.” He also said, “The materials retained … appeared to be mostly small to moderate-sized rock debris with some vegetative debris sticking through the net.”

It was evident, Gurrola said, that the net had been triggered.  That, he suggested, could only have been caused by something of substantial mass that hit the net high, fast, and hard. What was it? “We are currently assessing whether a debris flow or a peak flow discharge filled the net,” he said. 

Translating Gurrola’s findings, Pat McElroy — former Santa Barbara City Fire Chief and best known spokesperson for the Partnership—stated, “This year’s rocks were nothing like the rocks we saw in 2018. Back then, we were looking at rocks the size of cars,” he said. “This year we were looking at rocks the size of basketballs.” Even so, McElroy expressed confidence that this year’s floods demonstrated the value of the nets. “I think we proved the proof of concept,” he said. Even if this year’s rocks weren’t as big as the debris flow five years, McElroy cautioned, “There’s still a lot of stuff up there. And it can still come down. The question is whether these rocks would have picked up speed and gathered more material if they weren’t stopped.” 

Could they?

Too Early to Tell

“It’s still premature to say,” McElroy answered.

Gurrola was more definitive. Based on his research, debris flows have happened in Montecito far more frequently than has been previously recognized. Even if this year’s event was not of the debris flow magnitude, he argued, a subsequent one will be. And it’s unreasonable, he added, to rely on debris basins — no matter how big — to prevent the damage inflicted by a debris flows. Debris flows, he cautioned, can get knocked off their initial course. They bump into things and shift direction. They don’t always follow their creek channels. And creek channels, he added, change course over time. It’s what they naturally do. San Ysidro Creek, he noted, used to follow the path of what’s now El Bosque Road.  The choice is not between steel nets or debris basins, Gurrola argued; the solution, he said, is to have both. 

The rub, of course, is cost. How much insurance can the community afford? Thus far, it cost the Partnership more than $5 million to research steel nets, secure permission from the property owners involved, buy the nets, and install them. The nets were fast tracked through the permitting process on an emergency basis. What if there was another heavy rain? There was none of the customary public review. As McElroy noted,  steel nets are used in many states and countries. But this is the first time, he said, they were permitted in an environment where the Endangered Species Act was an issue. The creeks are habitat for the federally endangered steelhead trout. Even so, the partnership managed to secure emergency approvals from the county, the California Department of Fish and Wildlife, and the federal Army Corps of Engineers. But for just one year. The Partnership subsequently secured extensions that gave the nets four more years of permitted life. But those permits expire at the end of this year, on December 21, 2023. 

The $64 million question is what happens then.

McElroy said he’s hoping the county will agree to assume responsibility for the steel nets. “This is really  something government should do,” he said. “We’re citizen volunteers and we’re kind of tapped out.” Discussions between the county and the Partnership, however, are only just now getting underway. When Supervisor Das Williams was first asked about the county taking the project over, he balked. “We’re looking at spending $50 million to clear out the basins,” he said. “That’s money we don’t have. If we had to spend just half of that, it’s still money we don’t have.”  Williams said he would support extending the permits for the Partnership to keep the project going. Later, after the interview in which those comments were made, Williams reported that he and McElroy had subsequently spoken. After that discussion, Williams stated, “We will be meeting to determine the viability of a plan for next rainy season.” 

The other $64 million question is what happens to all the stones and rubbish behind the upper San Ysidro Creek steel net in the meantime. According to the permit conditions, the Partnership is required to begin removing the rubble from behind the net within 72 hours of the first inspection. They are required to airlift in a four-person crew and a Spyder excavator to restore the creek flow for the steelhead. Under the supervision of biologists, the crews will restore the creek flows; pools or eddies might need to be created that mimic that of the natural environment. All the stones and boulders, part of the natural life cycle of creeks, will have to remain in the riparian area. How far the boulders have to be moved will be up to the biologists. A portable wood-chipper — for wood — and a hydraulic rock splitter might be necessary.

How much all this costs is anyone’s guess. It won’t be cheap. When asked who pays for it, Williams was quick to reply, “The Partnership pays for it.” But Williams was also quick to note that the county supervisors assumed payment for a $1 million bond on behalf of the Partnership so that they could use their donations to pay for steel netting. “But there is a bond,” Williams noted, “in case they failed.”

In the meantime, however, Santa Barbara County Deputy Public Works Director Julie Hagen reached out to McElroy, notifying him that the partnership would be eligible to apply for FEMA reimbursements for clearing out the ring net. Hagen said she’d received a call from Congressmember Salud Carbajal’s office making inquiries on the Project’s behalf. “You would be applying for Public Assistance,” Hagen wrote. “We confirmed this option with FEMA and CalOES (Office of Emergency Services) staff currently in town reviewing the damaged sites.” McEloy said it’s not clear how much it would cost to clear out the ring net, but guestimated it would be in the ballpark of $250,000. “We’re still looking into that,” he said.


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