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Santa Maria Sun / News

The following article was posted on September 6th, 2017, in the Santa Maria Sun - Volume 18, Issue 27 [ Submit a Story ]
The following articles were printed from Santa Maria Sun [santamariasun.com] - Volume 18, Issue 27

Whittier Fire area may be dangerous during the wet season

By SPENCER COLE

The Whittier Fire may no longer pose a direct threat to nearby residents, but the effects from the blaze may be felt for years to come, particularly in the area’s main arteries of travel and at Lake Cachuma reservoir, according to a recent U.S. Forest Service report.

On Aug. 29, Los Padres National Forest biologist Kevin Cooper presented a Burned Area Emergency Response (BAER) analysis at the Santa Barbara County Board of Supervisors’ regular meeting. The report detailed several zones where the fire burned at high intensities, ravaging the soil in the process and creating prime conditions for winter debris flows and mudslides.

Cooper told the supervisors that the damage from the fire had created conditions that could overwhelm Highway 154’s culverts, which are too small to deal with extra debris during the wet season. He also listed major geologic hazards such as surface erosion, dry gravel, falling rocks, landslides, and slope failures, particularly on the north edge of the burn area, as pressing concerns.

“Debris flows on the north slope are likely to cause an immense amount of sediment to move down in the event of a heavy rain,” he said, adding that the slides and flows could be similar to those in El Capitan Canyon near Goleta last winter. “And those could come down and have an impact on Highway 154 and affect those culverts.”

Office of Emergency Management (OEM) Director Robert Lewin said the county was working with Caltrans to mitigate the problem, he didn’t specify how the state agency was doing so other than trying to stay active in keeping the culverts cleared of debris during storms.

Caltrans did not immediately return requests for comment.

Debris flows occur when already loose, largely barren, pre-saturated soil experiences a sizable amount of precipitation. In the land burned by the Whittier Fire, less than half an hour of hard rain could set one off, according to Cooper.

“A half-inch plus of rain per hour—even for 15 minutes can kick this off—most of that north slope is covered with ancient debris flows, so the situation is set up for these to occur again if the rain is intense,” he said. “That’s the wild card here—we don’t know what the rain will be, but the card that has not been dealt will determine how much material is moved from this area.”

Cooper noted that the forestland should recover naturally over the course of the next three to five years, depending on rain.

“But these first two years are crucial,” he said, adding that the intense rains and debris flows could also potentially wipe out fisheries in the area and that some of the fish population would most likely need to be relocated.

The Forest Service can treat about 1,900 acres of the affected land with hydro-mulching—planting a slurry of seed and mulch—on slopes that aren’t too steep or otherwise offer limited access. However, the price tag is high—around $14 million, with just one small parcel costing anywhere from $3,500 to $7,000 per acre—and the calculated savings in preventing sedimentation from entering Cachuma and endangering water quality is minimal, Cooper said.

In total, the mitigation work would only save the reservoir about 5 acre-feet in capacity.

“Even though it’s a very small amount, we understand that water capacity is very important to the county,” Cooper said, adding that the request for mitigation had been sent to the Forest Service’s Washington office, but policy dictated they could not shoulder the cost. “We can only treat valleys at risk that occur within our boundaries, but we are still receptive to that hydro-mulching taking place if the [Water Agency] feels that is a valuable thing to do.”

Santa Barbara County Water Agency Manager Fray Crease said water purveyors were aware of the potential water quality impacts of the lake and were taking steps to try to address them.

“It could be that they do something like not take Cachuma water until the material has settled out, but they are still investigating several ways how to mitigate that treatment for their water treatment plants,” Crease added.

Fourth District County Supervisor Peter Adam balked at the estimated price tag for the mitigation project and suggested slightly less effective but cheaper options.

“It just seems like that’s an immense amount of money—it’s just so much—especially at the county level,” he said. “Maybe it’s chump change for the feds, but for around here, that’s more than we could even fathom.”

Supervisors eventually decided to ask U.S. Rep. Salud Carbajal (D-Santa Barbara) for assistance. Carbajal wasn’t immediately available to comment for this story but his communications director, Tess Whittlesey, said Carbajal was currently working with the Forest Service to help secure funding for Whittier Fire restoration efforts.

The water treatment and road service expenses are additions to a long list of costs and damages that came as a result of the 18,000-acre wildland fire.

Besides the millions of dollars spent by the U.S. Department of Agriculture and the state of California to suppress the blaze, Santa Barbara County suffered losses and damages to some of its property.

According to a preliminary damage assessment summary report submitted to the Federal Emergency Management Agency on Aug. 10, the county suffered an estimated $934,933 in damages. More than half of those costs are related to damages to county infrastructure including roads and bridges, the report said. The numbers provided by the county were only estimates.

And although much of California’s wet weather is still weeks, if not months, away, recent rains in another area scarred by fire serve as a reminder of winter’s potential problems. On Sept. 3, the National Weather Service issued a flash flood warning for the Alamo Fire burn area near Orcutt, Sisquoc, and Highway 166 between Twitchell Dam and Cuyama Valley.

The rainfall was roughly three quarters of an inch per hour, around the threshold for debris flow, OEM Emergency Manager Ryan McMahon told the Sun.

“There's been no reports of damage, but that amount of rain is right about where something could happen,” McMahon said.

Staff Writer Spencer Cole can be reached at scole@santamariasun.com.




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