Estuary News

September 2020

The Delta’s Blooming Problem

Bright-green blotches of algae have been popping up all over the Delta since early summer, from Discovery Bay to the Stockton waterfront, befouling the air and poisoning the water with toxins that can sicken or even kill humans and animals. Veteran Delta watchers believe that this year’s harmful algal blooms may be the worst ever, and worry that some features of Governor Gavin Newsom’s recently released Water Resilience Portfolio for California will aggravate the problem.

“We don’t have enough data to know if this is the worst year ever, because we haven’t been out there every single year for years and years monitoring,” says Meredith Howard, an environmental program manager with the Central Valley Regional Water Quality Control Board. “I will say we’ve seen higher toxin numbers this year compared to the last three or four years.”

Although blooms are common in Discovery Bay and Stockton, “What was especially concerning this year is that we saw significant concentrations out in the Estuary as far as Antioch that were connected to the big Delta bloom,” says scientist Brian Bergamaschi of the U.S. Geological Survey (USGS).

Delta waterways in the summer can be ideal environments for the cyanobacteria that create harmful algal blooms (HABs). “There are certain areas of the Delta that don’t get a lot of flow for long periods of time, usually in the summer when it’s really warm. Cyanobacteria love that,” says Howard, citing the stagnant waters around Stockton as a particularly optimal spot for HABs. “Cyanobacteria grow faster in warm water.” The nutrients that spill into the Delta from agricultural land and urban runoff also stimulate their growth.

Despite the alarming number of blooms identified this summer, the true extent of the problem is unclear, as there is no formal monitoring program for HABs in the Delta. “HABs are kind of like COVID in that if you don’t track it, you don’t know what you’re really dealing with,” says Barbara Barrigan-Parrilla, director of Restore the Delta, which has been raising alarms about HABs since 2014.

In 2019, the governor signed AB 834, mandating a freshwater and estuarine HAB program. “That was supposed to give us a lot of resources starting in July 2020,” says Howard, but COVID-related budget constraints took that off the table.

Such a program will be challenging to design and expensive to operate, says Bergamaschi, who is studying the effect of cyanotoxins on Delta aquatic ecology. It can cost upwards of $350 to analyze each water sample for the toxins, not including the costs of “getting people into boats to collect the samples.”

Monitoring is also complicated by the fact that not every algal bloom is harmful. “Just because you can see an algae colony doesn’t tell you whether or not there are cyanotoxins in the water column,” says Bergamaschi’s USGS colleague Tamara Kraus. “There are different kinds of algae; some of them are beneficial and some of them are harmful. Some of them have the gene to produce the toxin, and some of them don’t. Some that have the gene are not necessarily making the toxin.” The conditions that cause the organism to produce the toxin are still unknown.

Although there is no formal HAB monitoring program in the Delta, an informal peer-to-peer scientific network is picking up some of the slack, says Howard. “There’s a huge number of groups that do monitoring [of various things] in the Delta. We’ve started to work with USGS and the Department of Water Resources, and we’re trying to get HABs incorporated into more of our regional monitoring programs.” In the meantime, the Surface Water Ambient Monitoring System, established in 2016, maintains an online portal that allows anyone to report suspected HABs. 

“There are a lot of active stakeholders who use that resource now,” says Howard. “It’s gotten to the point where there are actually more reports than we have staff to investigate.”

Howard is hopeful that a regular monitoring program will begin in 2021 (implementing AB 834 is one of the priorities identified in the Water Resilience Portfolio). In the meantime, Howard says she is talking with regional board members and stakeholders about developing a HAB mitigation and management strategy for the Delta.

To Barrigan-Parrilla, some solutions are obvious. “There has to be adequate fresh water flowing through the Delta all year round,” she says. Number two, we’ve got to do something about [nutrient-heavy] discharge from the Port of Stockton and agriculture. And number three, we need mechanical recirculation systems [where there are stagnant areas].”

Barrigan-Parrilla and others are worried that several priorities identified in the portfolio will limit the needed freshwater flows. These include the proposed Sites Reservoir, the latest iteration of the Delta tunnel, and reliance on voluntary agreements with water contractors to increase flows and improve conditions for native fish in the Delta.

“What’s going to happen when we are deprived of even more flow?” asks Barrigan-Parrilla. “Rather than just saying ‘no’ to the tunnel, we’re saying, let’s solve this problem and then talk about the tunnel. But [the Department of Water Resources] just doesn’t want to do that. And it’s the same with voluntary agreements. Nobody wants to do the hard work about how these issues are interrelated.”

New water quality standards for the Delta might go a long way toward resolving these issues, says Kate Poole of the Natural Resources Defense Council. In 2018, the State Water Resources Control Board released its Phase One update to the Bay-Delta Water Quality Control Plan, which set new standards for flows from the San Joaquin River. However, those standards have yet to be implemented. Phase Two, which would address flows from the Sacramento River, is on hold while the state tries to negotiate the voluntary agreements. Earlier this year, negotiations over the agreements dissolved when the parties—including state and federal agencies and water contractors—disagreed over Endangered Species Act requirements.

“The state boardneeds to get back to work on both the Phase One implementation and the Phase Two standards,” says Poole. “If the voluntary agreements come back to life, they can be plugged into that proceeding. But there’s urgency around this. We’ve lost decades already.” Poole says her concern about the Water Resilience Portfolio is that while it includes some laudable initiatives and approaches, “It doesn’t connect the pieces, which is what really needs to happen if we’re going to deal effectively with these big thorny problems, like restoring the health of the Delta.”

Central Valley Board Surface Water Monitoring Program

Restore the Delta Articles on HABs

San Francisco Bay Nutrient Management Strategy

Related Estuary News Articles

Federal Research Crew Bucks Headwinds and Helps Prevent HABs, March 2019

Four Stories on New Science and Tech for Monitoring HABs, Pearls 2019-2020

Nutrient Nuances Modeled, September 2016

Bay Primed for Pea Soup? March 2014

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Top photo courtesy DWR

About the author

Cariad Hayes Thronson covers legal and political issues for Estuary News. She has served on the staffs of several national publications, including The American Lawyer. She is a long-time contributor to Estuary News, and some years ago served as its assistant editor. She lives in San Mateo with her husband and two children.

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