DWR Updates

Delta smelt are raised at the UC Davis Fish Conservation and Culture Laboratory in Contra Costa County, California, to be released into the Sacramento-San Joaquin Delta to support the wild population. Photo taken January 8, 2025.

Little Fish, Big Decisions: How Science Guides Actions in the Delta

California’s water system is one of the most complex and important in the world. It delivers water to millions of people across the state and supports ecosystems that are vital to California’s environmental health.

Published: February 23, 2026

An aerial view of a designated brood pond area at the Thermalito Afterbay. Water surrounds two small, vegetated islands.

Lake Oroville Update - February 20, 2026

Published: February 20, 2026

Amelia Ayers, a Physical Scientist with the U.S. Geological Survey, packs up gear used to gather shellfish samples collected at Martinez Harbor, Contra Costa County. The shrimp are tested for levels of toxins found in Harmful Algal Blooms (HABs). The work is part of a five-year, $3 million grant for the Monitoring and Event Response for Harmful Algal Blooms (MERHAB) research program, a focused effort co-lead by DWR. A comprehensive and focused effort co-lead by DWR, MERHAB is focused on building an estuary-wide management strategy for HABs. Xavier Mascareñas / California Department of Water Resources

DWR Partners with Agencies to Untangle Mystery of California's Harmful Algal Blooms

Appearing like something out of science fiction, harmful algal blooms (HABs) can form thick mats that accumulate on freshwater surfaces throughout California.

Published: February 19, 2026