- By Melinda Burns
Why Supes OKed Flood Maps, Despite Doubts
The new Federal Emergency Management Agency recovery map for Montecito and the Carpinteria Valley, dramatically expanding the flood plain in both communities, was adopted by the county Board of Supervisors this week, paving the way for survivors of the Jan. 9 debris flow to begin rebuilding their homes.
Voting 5-0 on Tuesday, the board took note of the differences between the FEMA map, which is based on computer models of a 100-year flood in a burned watershed, and the actual footprint of the catastrophic debris flow, as mapped on the ground by the California Geological Survey.
“I can’t say I’m comfortable with the option” of the recovery map, said board Chairman Das Williams, who represents Montecito and Carpinteria. However, he added, “I’m convinced by the assertion that what we need to prepare for is more like a debris-laden flood than a debris flow. And I would still advise property owners to try to do both.”
Rebuild - but where? Dianne Black, county director of Planning and Development, told the board that planners “have had quite a few meetings” with Montecitans wishing to rebuild since last week, when the FEMA map was first released.
Based on the new flood water elevations as defined on the map, they may be required to rebuild farther away from creeks or raise the first floor of their new homes. Any postponement in adopting the map, Black said, “would delay our ability to meet with property owners in a meaningful way.”
To date, officials said, the owners of 184 out of 321 properties in Montecito with one or more damaged structures have contacted Planning and Development for assistance with rebuilding.
Tom Fayram, deputy director of county Public Works, told the board that the recovery map was much more accurate than the Flood Insurance Rate Map (FIRM) for Montecito and Carpinteria, last updated by FEMA in 2012.
“It’s night and day, in my opinion,” Fayram said.
The new flood plain, defined as a “high hazard area,” appears roughly to cover half of Montecito and two-thirds of the Carpinteria Valley. It is easily twice as large as on previous maps.
“We are drastically increasing the areas that we are identifying as being at risk,” Fayram said.
Scenarios for disaster. The recovery map more closely reflects the danger of a debris-laden flood over the next three-to-five years, depending on how soon the vegetation grows back on the steep slopes that were burned by the Thomas Fire, Fayram said.
At the county’s request, he said, FEMA analyzed a real-world scenario, in which heavy rains would bring down mud and rocks from the mountains and plug up bridges, causing the creeks to jump their banks and flow across the landscape. In the historical record, debris-laden floods occur much more frequently than debris flows, Fayram said.
For mapping purposes, FEMA assumed that 15 inches of rain in 24 hours in the mountains or eight inches of rain in 24 hours on the coast of Montecito and Carpinteria would trigger a 100-year storm – that is, an event with a one-percent chance of occurring in any given year.
“Longer-duration, heavy rainfall that triggers a debris-laden flood is a more likely scenario than the repeat of a debris flow,” Fayram said, adding that scientists don’t yet know whether there remains enough rock piled up in the canyons above Montecito to trigger another catastrophe.
“This map is far superior to anything we have ever had,” he told the board. “It will allow people to build and understand the risk they have over the next couple of years. We owe FEMA a big thank you.”
FEMA will begin updating the 2012 FIRM map next month; it will be completed in three-to-five years, at which time new flood insurance rates will go into effect.
Not so fast, please. Tom Bollay, a Montecito architect who lives in Riven Rock, urged the board to delay adopting the map so that property owners could do their own engineering studies and gather more specific data.
Many properties above East Valley Road that were damaged on Jan. 9 do not appear in the blue-shaded areas of the new FEMA map.
The blue areas identify places that would likely be inundated with water six inches to more than 10 feet deep during a 100-year flood.
“It is not portraying to the community the correct level of risk for this area of Montecito,” Bollay said.
Fayram said the apparent discrepancy was not an error, but rather a reflection of the difference between a flood and a debris flow.
On Jan. 9, he said, there were properties where the front of a building was buried in 10 feet of mud and debris, while the back of the building and the landscaping in the back yard were untouched. A flood behaves differently; it moves faster and spreads out farther, Fayram said.
Also, in the upper reaches of the mountain slopes above East Valley, the creek channels were scoured down to bedrock on Jan. 9, Fayram said. The creek capacity up there is now much greater than it was before the debris flow, Fayram said, and the recovery map reflects that.
The supervisors said they did not want to make residents wait any longer to start rebuilding. But they advised them to consult the California Geological Survey map of the Jan. 9 debris flow along with the FEMA recovery map to get the full picture.
“It’s important that staff are empowered to give real straight advice to people,” Williams said.
The interactive FEMA recovery map can be viewed at readysb.com.
The California Geological Survey map of the Jan. 9 debris flow can be viewed on the interactive map on the county Planning and Development website, showing properties in Montecito that were damaged on Jan. 9. To get the Geological Survey map, click on the icon of stacked papers in the upper right-hand corner of the interactive P&D map and check “Debris Flow Area.”
More for disaster. Meanwhile the board on Tuesday also authorized county Flood Control to begin receiving bids for restoration work in 10 debris flow basins above Montecito and Carpinteria, post-Jan. 9.
The work includes rebuilding or repairing fencing, railings, access gates, fish passages, gravel access roads, pipes, and grouted rock walls. It is estimated to cost $1 million.
Finally, the board awarded a $1.1 million contract to Summer Construction, Inc., a tri-county company with the lowest bid for the remaining cleanup work at the Santa Monica debris basin above Carpinteria. Santa Monica is by far the largest debris basin on the South Coast – it holds 158,000 cubic yards of material.
All but 15,000 cubic yards was removed by the U.S. Army Corps of Engineers. In all, the Corps removed 400,000 cubic yards of debris from all the basins above Montecito and Carpinteria, post-Jan. 9.
The county has requested reimbursement from FEMA for the remaining debris basin restoration and cleanup projects.
Melinda Burns is an environmental journalist based in Santa Barbara.
\Images: Scenes of the impact of the Jan. 9 catastrophe by Mike Eliason, Santa Barbara County Fire Department; Recovery map from FEMA website.