Full and rising reservoirs from this winter’s storms have the Santa Barbara County Board of Supervisors poised to terminate the drought-caused emergency declaration, although South Coast purveyors are worried a water shortage will persist for an extended time, according to a county staff report.
Office of Emergency Management Director Rob Lewin noted that despite the recent abundance of precipitation, it could take years of above-normal or at least normal rainfall before the county’s severely depleted groundwater basins are recharged.
Still, supervisors are scheduled to adopt a resolution terminating the proclamation of a local drought-caused emergency when they meet at 9 a.m. Tuesday in the Board Hearing Room on the fourth floor of the County Administration Building, at 105 E. Anapamu St., in Santa Barbara.
Supervisors will also consider approving a “resolution of concern” for a prolonged water-supply shortage, particularly in the Santa Barbara and Montecito areas, as increased sedimentation has reduced not only storage capacity but also water quality in their reservoirs.
It’s not unusual for Santa Barbara County to experience one or two “dry” years, when less than 80 percent of the average amount of rain falls, sandwiched in between three to five years of “normal” and “wet” years, when more than 125 percent of the average rain falls.
But 2012 marked the first of five years when precipitation was 69 percent of average or less, dropping to 40 percent of normal in 2014, when on Jan. 15 the U.S. Department of Agriculture declared Santa Barbara County and 26 others natural disaster areas because of the drought.
Two days later, California declared a statewide drought emergency and Santa Barbara County declared a local emergency.
At that point, Cachuma Lake, which supplies drinking water to 250,000 South Coast residents and drinking and agricultural water to another 80,000 downstream, was at 39 percent of capacity.
As the drought deepened, the county’s reservoir levels fell. Cachuma would eventually bottom out at about 7 percent of capacity.
In 2017, California was hit with repeated storms that filled Northern California reservoirs and left a heavy snowpack in the Sierra Nevada, prompting the governor to declare the drought over.
Santa Barbara County received 136 percent of normal precipitation that year, but despite the governor’s declaration, it wasn’t enough to end the county’s drought, and in 2018 precipitation countywide fell again to 54 percent of average.
But in his report, Lewin noted the storms this year have brought enough rain to put the countywide total at 144 percent of normal for the year to date as of March 8 and 114 percent of normal for the entire water year, assuming no more rain falls after that date.
“Drought conditions in Santa Barbara County have improved to a level that a proclamation of a local emergency no longer is necessary,” Lewin said in his report, although he noted the aquifers have yet to recover.
“It will take several average or better rainfall years to fully recharge the groundwater basins, which were significantly depleted during the drought,” he wrote.
“However, because the reservoir(s) are full or rising, and state water allocations are anticipated to be increased, the need for groundwater could be reduced depending on how the water is managed.”
As of Friday, Cachuma Lake was holding 143,750 acre-feet, or 74.4 percent of capacity. Twitchell Reservoir, whose primary purpose is flood control but serves as a source of water for Santa Maria, was holding 45,004 acre-feet, or 23.1 percent of capacity.
Gibraltar Reservoir, which provides water to Santa Barbara and feeds its overflow into the Santa Ynez River and Cachuma Lake, was at 100.4 percent of its 4,314 acre-feet of capacity, and Jameson Reservoir, which serves Montecito Water District, was at 100 percent of its 1,544 acre-feet of capacity.
But one caveat on reservoir capacity is the impact of sedimentation.
Lewin noted the Rey fire in 2016 and the Whittier and Thomas fires in 2017 burned areas of the watersheds for Cachuma, Gibraltar and Jameson reservoirs.
“All three reservoirs continue to be impacted with increased sedimentation from the burn areas,” Lewin said. “This impact will continue depending on the amount and the intensity of rainfall over the next two to three years’ winter storms.
“This will impact their overall water storage capacity,” he continued. “In addition, water quality has been reduced with the increased sedimentation and organics to both Jameson and Gibraltar reservoirs.”
Santa Barbara’s desalination plant is producing drinking water for the city and has the capacity to produce about 3,125 acre-feet of water a year.
Montecito is negotiating to purchase some of that water, but South Coast purveyors are concerned about a continuing shortage of water.
“Recurring droughts in Santa Barbara County are more likely with the impacts of climate change,” Lewin said. “If drought conditions reoccur, a new local emergency may need to be proclaimed.”
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