“Our goal was to improve estuarine habitat by increasing net flows through the Cache Slough Complex to enhance downstream transport of lower trophic-level resources, an important driver for fish such as the endangered Delta Smelt,” write the authors—including esteemed (and recently retired) California Department of Water Resources lead scientist Ted Sommer—in the latest issue of San Francisco Estuary and Watershed Science. The pulse occurred over three weeks in July, a time when flows in the region above Cache Slough are often negative (meaning they go “upstream”) due to agricultural diversions and low freshwater inflow. Producing the pulse, which increased downstream flows from about negative-two cubic meters per second to a peak of 15 cubic meters per second in the Toe Drain of the Yolo Bypass, required releasing water from upstream reservoirs and pumping from downstream diversions in the Sacramento River.
 
“It was a lot of heavy lifting in a short amount of time, but an amazing collaborative effort,” says lead author Jared Frantzich, a senior environmental scientist with DWR, which led the effort in partnership with a host of other agencies, irrigation and reclamation districts, and private landowners. Subsequent managed flow pulses in 2018 and 2019 provided additional data and helped refine the practice, which Frantzich notes has since been included in some key Delta regulatory documents and may be used more in the future to help benefit food web and habitat conditions during summer or fall months.

Pearls in the ocean of information that our reporters didn’t want you to miss
Photo by Jared Frantzich
 

A large pulse of water sent through the Yolo Bypass in summer 2016 boosted phytoplankton biomass and food web conditions in Cache Slough and the lower Sacramento River, a new report confirms.

 “Our goal was to improve estuarine habitat by increasing net flows through the Cache Slough Complex to enhance downstream transport of lower trophic-level resources, an important driver for fish such as the endangered Delta Smelt,” write the authors—including esteemed (and recently retired) California Department of Water Resources lead scientist Ted Sommer—in the latest issue of San Francisco Estuary and Watershed Science. The pulse occurred over three weeks in July, a time when flows in the region above Cache Slough are often negative (meaning they go “upstream”) due to agricultural diversions and low freshwater inflow. Producing the pulse, which increased downstream flows from about negative-two cubic meters per second to a peak of 15 cubic meters per second in the Toe Drain of the Yolo Bypass, required releasing water from upstream reservoirs and pumping from downstream diversions in the Sacramento River.
 
“It was a lot of heavy lifting in a short amount of time, but an amazing collaborative effort,” says lead author Jared Frantzich, a senior environmental scientist with DWR, which led the effort in partnership with a host of other agencies, irrigation and reclamation districts, and private landowners. Subsequent managed flow pulses in 2018 and 2019 provided additional data and helped refine the practice, which Frantzich notes has since been included in some key Delta regulatory documents and may be used more in the future to help benefit food web and habitat conditions during summer or fall months.

About the author

Nate Seltenrich is a freelance science and environmental journalist who covers infrastructure, restoration, and related topics for Estuary. He also contributes to the San Francisco Chronicle, Sonoma and Marin magazines, the journal Environmental Health Perspectives, and other local and national publications, on subjects ranging from public lands and renewable energy to the human health impacts of climate change. He lives in Petaluma with his wife, two boys, and four ducks. www.nate-reports.com

Related Posts

Atmospheric Rivers Intensifying as World Warms: How the West Will Know What’s Coming

In just a few years, tracking the West Coast’s atmospheric rivers by airplane has gone from what one hydrologist called “really wild-eyed stuff” to a Congressionally-funded operation. This Atmospheric River Reconnaissance program, which wrapped up its latest season in March, monitors these increasingly powerful storms as they shoot across the...

Scientists in the Central Valley are honing a novel way of giving young salmon the nourishing benefits of wintertime floodwaters without undertaking costly floodplain restoration work.

The method, being practiced along the Sacramento River, mimics the flood patterns of natural Sacramento Valley wetlands by diverting water onto floodplain farm fields, retaining it there for three weeks, and finally flushing the water—now rich with zooplankton and invertebrate protein—back into the river. Onsite studies have shown that salmon...

Hot off the press, Sacramento County Breeding Birds: A Tale of Two Atlases and Three Decades of Change raises red flags for some of the county’s wetland species.

Breeding bird atlases use field observations to record possible, probable, or confirmed nesting in uniform-sized blocks within a county or state. Biologist/artist Tim Manolis led a Sacramento County atlas project in 1988-93, but the results were never published. When Edward Pandolfino of Western Field Ornithologists heard about it he suggested...