Drought — Carquinez Strait and Delta, California

2021-05-01 to 2021-05-31 · Carquinez Strait and Delta, California

Event narrative

For the month of May, the U.S. Drought Monitor put all of zone 18 in exceptional drought (D4). They continue to mention that we will see drought impacts expand into the summer, including but not limited too: agriculture, water supplies, recreation, and ecosystems. They also started noting concern for the upcoming wildfire season and that drought preparedness is key since given back-to-back dry years. A giant rock wall will be constructed across a river in the Sacramento-San Joaquin River Delta to protect a vital freshwater estuary from saltwater as rivers become too low to push the brackish waters from the bay. The $30 million barrier will be built in the same place as it was in 2015 on the West False River to keep saltwater away from pumping stations. This will protect a water source for nearly 30 million Californians. Construction slated to begin by June 1 and be complete by July 1. The barrier will be removed before Nov. 30. Farmers north and south of the Sacramento-San Joaquin River Delta will receive no water from the Central Valley Project. The agency previously had forecast a 5% allocation. On May 10th, governor Gavin Newsom included all of zone 18 in the official drought emergency proclamation. The Delta cross channel gates were closed on May 20th.

Wider weather episode

Northern California typically experiences a wet season, October through May, and a dry season May through September. Last year's water year, October 2019 through September 2020, was one of the driest on records. This likely contributed to the U.S. Drought Monitor's decision to place portions of interior northern California into extreme drought on September 29, 2020. Portions of Shasta, Tehama, Butte, Glenn, Colusa, Yolo, Solano, Yuba, Nevada, and Sacramento counties remain in extreme drought. The rest of interior northern California was placed into severe drought (D2) on December 8; however, the state of California has not announced that these locations are in drought. On 4/21/2021 the Biden-Harris administration announced the formation of an Interagency Working Group to address worsening drought conditions in the West. On 5/10/2021 Governor Gavin Newsom significantly expanded his April 21 drought emergency proclamation to include Klamath River, Sacramento-San Joaquin Delta and Tulare Lake Watershed counties where accelerated action is needed to protect public health, safety and the environment. In total, 41 counties are now under a drought state of emergency, representing 30 percent of the state's population.

Source: NOAA Storm Events Database, event_id 962283. Narrative written by the NWS forecast office that issued the report.