Floodgates open as Cachuma fills up

 By Callie Fausey

January 14, 2023 10:06am

The water release from Bradbury Dam at Lake Cachuma, which is here flanked by storm-related debris, is set to start on January 14.

                                          After a series of winter storms this year, Lake Cachuma is overflowing, and Santa Barbara County water managers are momentarily rejoicing that things are looking good for the region's water supply. Cachuma is almost at capacity for the first time in 12 years, and a release is scheduled to prevent a spill over Bradbury Dam.

According to Joshua Haggmark, water manager for the City of Santa Barbara's Public Works Division, "the last time Cachuma leaked, many of my employees did not yet work for the city, making this upcoming disaster both noteworthy and memorable."

As of Friday night, Lake Cachuma had grown by more than 50% since the start of this year's series of storms and was over 87 percent full. The dam's gates will be opened for eight days starting at 10 a.m. on Saturday by the U.S. Bureau of Reclamation, which is in charge of managing the lake's operations and maintenance.

The county Water Agency's Matt Young stated that the bureau's objective was to create "a little room" in the Cachuma reservoir before to this weekend's storm. To achieve a full reservoir after the storm, the ultimate goal is to maintain a balance between the water entering the lake and the water being discharged.

Water from the dam will help restore groundwater resources as it runs through the Santa Ynez River system, where it can also be diverted by water users downriver until it eventually reaches the ocean.

Fourth District Supervisor Bob Nelson voiced worry about potential repercussions if the water was released too quickly and in excessive amounts, a worry that was echoed by several municipalities downriver. Although the storm on Monday carried almost 20,000 cubic feet of water per second down the river at its height, the agency claims it plans to discharge flows that are "much lower than what the storm sent down the river."

According to Lael Wageneck of County Flood Control, "USBR [U.S. Bureau of Reclamation] is managing the reservoir to optimise water supply while safeguarding towns downstream from floods." The three wettest months of the year are still ahead of us, but we are entering them now with a full reservoir since it is still very early in the rainy season. The USBR is watchful for storms approaching and works to prevent them from causing floods downstream.

According to meteorologist Eric Boldt, the rains this weekend are not anticipated to be "anything close to what occurred early in the week," which were caused by a variety of meteorological factors, including a west to east jet stream that originated around Japan. According to Boldt, the Warning Coordination Meteorologist with the National Weather Service out of Oxnard, the jet "delivered the steady conveyor belt of low pressure systems, each with a tap of the atmospheric river that frequently contributes to floods in the state."

However, Boldt noted, "We know that the earth is saturated and that the amount of material that catch basins can hold is smaller. "We believe that these storms will have only minor effects, mostly occasional urban and small stream flooding, and are more usual for this time of year. Through much of the next week, surf conditions throughout the Central Coast and in Ventura County are likewise expected to be very high.

Haggmark referred to the recent storms as a "game-changer" for the safety of the water supply in the City of Santa Barbara. If this winter was dry, Haggmark added, "we were ready to strengthen our water scarcity situation and apply exceptional conservation restrictions this spring to stretch our resources even farther." The city has enough water to fulfil demand beyond our three-year planning horizon and won't need to enact any obligatory conservation measures this spring and summer because Gibraltar is spilling and Cachuma is imminently approaching a spill.

The City of Santa Barbara may start paying off its water debt with all this liquid as well. According to Santa Barbara City Councilmember Eric Friedman, the city has borrowed desperately needed water from neighbouring jurisdictions in past years, accruing quite the water "debt." Santa Barbara was unable to repay the water it had borrowed because of reductions in allocations from the California State Water Project during drought years.

But now, this enables us to use the state water we already possess to pay back the outstanding water debt, according to Friedman. Additionally, it indicates that we will probably receive an increase in our yearly state water allotment - but I can't tell for sure until it's official. As a result, we are in a position to seriously consider and dramatically reduce the water debt we owe to other jurisdictions in the upcoming months and year.

On a molecular level, the water in Cachuma Lake is identical, yet on paper, it's a puzzle of accounting. According to Wageneck and Young, the filling of the lake is extremely advantageous for the hundreds of thousands of people provided with services by the five agencies that receive water from Cachuma — extending from Santa Ynez to Carpinteria.

They didn't receive any new water from Cachuma last year, according to Wageneck. "The lake was just 30% filled, and the situation appeared quite hopeless. Therefore, it should go without saying that filling the lake has a significant impact on those agencies' short-term water supply.

Reduced drought intensity is a result of increasing rainfall and water availability. On the four-tier scale used by the state drought monitor, portions of California have gone from "exceptional" and "extreme" drought to "severe" and "moderate" since early January. Since late November, the severity of the drought in Santa Barbara County has decreased from "severe" to "moderate."

But the drought issue goes far deeper than that. Lake Cachuma is only a drop in a rather dry bucket, and Santa Barbara is still at the mercy of Southern California's arid environment. Mother Nature likes to give just as much as she loves to take away.

Many Central Valley reservoirs, according to Wageneck, are not full and the drought is "far from done." Notably, it "takes considerably more than one rain event to recharge" groundwater basins, which are the county's main supply of water. It will take "many years of above-average rainfall to recharge and fill back up" for those crucial, and considerably overdrawn, county-wide bathtubs, he added.

Therefore, even while recent rain has been beneficial and increases surface water storage, Wageneck noted, "it does not mean our statewide drought is ended.

Then there is a condition known as "weather whiplash." According to Wageneck, "Cachuma leaked in 2011, and by 2016, the lake's volume had decreased to 6%. Due to recent average rain years, we are once again operating at full capacity. Therefore, even with recent rain, this lake might return to a single-digit capacity in five years, not to mention that the drought is still ongoing.

Although he acknowledged that it would be premature to declare the drought to be ended, the city's Haggmark, who has a desalination plant to back up his water resources, had a more "glass half full" outlook on the situation.

According to him, the State Water Project's large reservoirs are now at roughly 40% of their maximum capacity, which is much more than normal for this time of year. If the rainy weather persists during the winter, the reservoirs should fill and maybe overflow. He mentioned that a few of the larger reservoirs were refilled in the early summer by snowmelt. At some locations, the snowpack is currently 200 percent of average, which is quite encouraging. However, since it is still early in the winter, I believe the California Department of Water Resources will postpone making significant revisions to the State Water Project allotment.

However, in the coming months, Haggmark's staff plans to recommend to the City Council that the water shortage situation and related conservation measures be reversed in Santa Barbara. He said, "Rolling back our water supply condition would imply the city is officially out of the drought for the time being," but noted that California's State of Emergency may take longer to lift.

Depending on the capacity of the groundwater basins and the water agreements reached between the various water agencies, the impact of the drought varies from area to region within the county. According to the county's Matt Young, Carpinteria was "in stage three with obligatory conservation," although Solvang was "at a higher stage of mandatory conservation earlier."