Much of our state, including the Santa Ynez Valley, depends upon surface water storage to provide long-term reliable water supplies for homes, business, and agriculture. There are three such water storage reservoirs on the Santa Ynez River:
Jamison Reservoir, in the far uppermost part of the watershed which is owned by the Montecito Water District. Water from this reservoir is diverted through a tunnel bored under the mountains for the exclusive use of Montecito residents.
Gibraltar Reservoir, downstream from Jamison at the far end of Paradise Road, above the Red Rock area, is owned by the City of Santa Barbara. Water from this reservoir is diverted through another tunnel under the mountains for exclusive use by the City of Santa Barbara. A court action in the last century dictated that a small amount of the captured water had to be released for downstream users.
Lake Cachuma, which is downstream of both Jamison and Gibraltar, is owned and operated by the United States of America. It is paid for by water users on the South Coast and Improvement District No. 1. About 90 percent of the annual yield of the Lake is diverted to the South Coast through a 7-mile long tunnel for use by Goleta, the City of Santa Barbara, Montecito, Carpinteria, and Summerland. Several State Water Board decisions, which govern Lake Cachuma operations, require periodic large water releases be made from the Lake to meet the needs of downstream users. Those relying on these water rights releases include the Santa Ynez area, farmers along the river, and the Cities of Solvang, Buellton, and Lompoc.
Historically, these three reservoirs have filled to the top and spilled excess water into the river on average of once every three to four years. The last time this occurred was in 2011. One could conclude that there should be a high probability that 2019 would mark a year of recovery for the Santa Ynez reservoirs to a full or at least near full condition. On the other hand, modeling based on the historical record shows that there could be as much as a 10-year span between spill events. Even so, probabilities are just chances, not guarantees.
We know that on average February is the largest rainfall month. We also know that by mid-March, the die is cast so to speak on rainfall and runoff. It is true that enough rain can come after mid-March such that what at first appears to be an average year can ultimately be a wet year. However, it is extremely unlikely that a mid-March dry year can be made into a wet year due to “April showers bringing May flowers”.
As much as we would like to know in advance if the rains this winter will replenish our reservoir supplies, ultimately we will have to just “wait and see”.