Built by the
U.S. Bureau of Reclamation in 1953, the name "Cachuma" comes from a
Chumash village that the Spanish spelled "Aquitsumu", from the
Barbareño Chumash word ''aqitsu'm'', meaning "sign". The U.S. Bureau of Reclamation oversees the lake’s operations and maintenance. Five agencies that stretch from
Santa Ynez to
Carpinteria take water from Cachuma. The Central Coast Water Authority (CCWA) extension of the
California Aqueduct completed in 1997, is a that travels from
Vandenberg Space Force Base through
Vandenberg Village,
Lompoc,
Buellton, and
Solvang and terminates at Cachuma.
Water Levels The water levels of the lake are highly variable, spilling in some years and receding to less than 10% of capacity in dry years. Drought conditions can cause shortage in water supplies, as did the
2011-17 drought. In October 2016, the lake approached low levels not seen since the construction of Bradbury Dam. The lake level reached a minimum of on October 14, more than below the spillway elevation. At this time, the storage volume was only , approximately 7.3% of capacity. By the end of February 2017, the Lake had become 44.5% full, with a total volume of . The Lake's water level declined again during the 2017-18 water year, with the Lake receding to less than one-third of its capacity. By March 28, 2019, above-normal precipitation had restored Lake Cachuma to 78.0% of its capacity. Despite an abnormally dry January and February 2020, a wet March and April brought the lake to 77% of capacity as of April 7, 2020. Several consecutive
atmospheric river storms coming in from the Pacific in
late-December, 2022 and early-January, 2023 dramatically raised the water level in the lake, from an average of 33% full in late December, to nearly 100% full by January 15, 2023 for the first time in 12 years. Further storms in February resulted in flood warnings for portions of Lompoc close to the river due to the water being released from the dam. == Climate ==