With the firestorms of the Thomas Fire now past, Santa Barbara County officials are now worried about another kind of storm.
Although December thus far has been extremely dry, crews are in the field working to improve flood-control facilities that will be crucial if the area receives substantial rains later this winter.
“Basically what we’re doing is we’re going to start working on debris basins,” Tom Fayram, the county’s water resources deputy director, told Noozhawk as flames were still burning in the hills above Carpinteria, Montecito and Santa Barbara earlier this month.
Flood-control workers started in Gobernador Canyon, at the eastern end of the Carpinteria Valley, making sure the debris dams are cleaned out and removing some of the silt from them, Fayram said.
Most of the canyons across the front country from Carpinteria to Montecito have debris basins, which were constructed in the wake of past wildfires.
The basins — basically small dams — are designed to slow down the flow of storm runoff and capture debris and silt that otherwise would flow downstream, potentially endangering populated areas below.
As they do their job, they fill up with debris and silt, which must be removed in order for them to remain effective.
“They were really built for fires,” Fayram explained. “Now our standard operating procedure is we will totally clear them out and get them ready for inflow and debris.”
County crews did their regular maintenance on the debris basins this fall, but are doing it again due to the fire-damaged watersheds.
The chaparral-covered hillsides that are endemic to Santa Barbara County are able to slow and absorb rainwater, even from heavy storms, allowing much of it to percolate into the groundwater tables.
But the denuded hillsides in the wake of a wildfire lost almost all of that capability, so that the rainfall runs off mostly unimpeded.
That can lead to serious downstream flooding.
“The amount of water that comes off a burned watershed is so much higher, and there’s no abating that,” Fayram said. “There’s an additional risk that people need to be aware of.”
Such was the case in January in El Capitan Canyon, which lies below the burn area from last year’s Sherpa Fire.
Localized heavy rainfall caused El Capitan Creek to rage, sending a torrent down canyon that damaged numerous structures and vehicles at the El Capitan Ranch Park.
Debris basins affected by the fire are in Gobernador, Santa Monica, Arroyo Paredon, Toro, Romero and San Ysidro canyons, among others, Fayram said.
Crews were in Toro Canyon this week, and will keep up their efforts until all the basins have been cleared.
Fayram said he is keeping a particular eye on Romero Canyon.
“That’s one I’m a little worried about, because the whole watershed got cooked,” he said.
Beyond the work in the field, county staff will be working to educate the public about the threat of flooding in areas below the fire.
Click here for the county’s “Homeowners Guid for Flood Prevention and Response.”
Printed copies also are available from county offices.
People contemplating buying flood insurance also should be aware that there is a 30-day hold after purchase before it kicks in, Fayram said, so someone buying it this coming week won’t be covered for damage until late January.
Fire-related flood problems also exist on the north side of the Santa Ynez Mountains, from both the Thomas Fire and last summer’s Whittier Fire.
The Thomas Fire charred virtually the entire watershed above Jameson Lake, which serves Montecito, and burned partially into the watershed for Gibraltar Reservoir, which supplied the city of Santa Barbara. Last year’s Rey Fire also blackened areas above Gibraltar.
The Whittier Fire denuded much of the watershed on the south side of Lake Cachuma, which served as a water supply for the South Coast as well as the Santa Ynez and Lompoc valleys.
Runoff from fire areas during heavy storms can carry tons of debris into the reservoirs, including fine organic particulates that can be difficult to treat, Fayram said.
The result is the water from the lakes may not be usable for a period of time, which means water agencies will have to rely on ground water, desalinated water and whatever other supplies they can muster.
County emergency officials are already planning for how to deal with such supply curtailments.
A painful irony of this year’s winter rainy season is that a series of light runs would be ideal for helping regenerate the burned areas and minimizing flooding problem.
But that would do little to address the lingering drought and need to refill reservoirs that have not fully recovered from years of drought.
Santa Barbara County overall has received only 11 percent of normal precipitation for the rain year that began Sept. 1, and Lake Cachuma is at 38.7 percent of capacity.
“We need rain, but we’re damned if we do get it and damned if we don’t,” Fayram said.
— Noozhawk executive editor Tom Bolton can be reached at tbolton@noozhawk.com. Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.
