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Delta Flows HABs in Stockton: Perspective from a resident scientist

Spencer Fern, Science Coordinator, Restore the Delta, [email protected]

Over the past few years, Stockton has been plagued with a blue-green nuisance known as harmful algal blooms (HABs). As the Science Coordinator for Restore the Delta, I run Restore the Delta’s HABs monitoring program to help fill in data gaps for government agencies related to Stockton waterways.

Growing up on the Delta I was able to travel by boat to many locations throughout the region. I also attended a high school in downtown Stockton where our physical education classes were always around the water at McLeod Lake. I never wanted to jump in the water at the Stockton waterfront because of how dirty and foul-smelling the waters are. This dread of the Delta’s unclean water was reinforced by the opinions of many people on those boating and recreating adventures. When running miles up and down the catwalk near Mcleod Lake in downtown Stockton (part of the urban Delta), I’d catch bad odors coming from the water. I never thought more about it because I was accustomed to these conditions. It wasn’t until college that I learned about HABs and realized that those foul odors I grew up smelling were likely HABs. As students, we were never warned about how dangerous they could be. 

Overall, in Stockton (and much of the state) there is a lack of awareness among the community about the HABs problem. This is a failure of regulatory and public health agencies to track, identify, and communicate what is happening. Sadly, most Stocktonians believe the conditions around water quality in our local waterways cannot be improved. Restore the Delta aims to change that dynamic, starting with our HABs monitoring program.

The monitoring program in 2022 focused specifically on Microcystis, which is the most prevalent HAB in the Delta. Microsystis can cause a variety of health issues ranging from skin rashes to liver illness. With the help of the Regional Water Quality Control Board (RWQCB) we were able to standardize the water sample data my team collects with the data collected statewide by other agencies. 

We collect samples from several sites around Stockton to test conditions for ourselves then send them to UC Santa Cruz for more in-depth analysis. This allows us to see what was going on. Our Climate Water Advocates, specifically Cintia Cortez and Gloria Alonso Cruz, help with collecting samples and sharing our findings. Increasing awareness of the dangers of HABs is made easier with social media. 
(Follow us @ FBTwitIG, or @[email protected])

The data collected from the sampling in 2022 showed that areas around McLeod Lake, Morelli Park, and Mormon Slough in downtown Stockton were most affected by bloom activity. American Legion Park (Smith Canal) also showed the first bloom activity in Stockton in late May. We hypothesize that the rising water temperatures throughout the testing period led to the blooms in these areas. American Legion Park had the highest temperatures initially, likely due to the water hitting a dead end with a lack of flow and constant sun exposure. Flow is a major issue when it comes to HABs. Lack of flow causes the water in many of the areas around Stockton to remain stagnant, which helps blooms form along the surface water. 

The optimal temperature for HABs sits between 70-80° F and temperatures from late May on most of the testing sites were sitting in the high 70s and low 80s. As the temperatures are colder now, we shouldn’t be seeing any blooms until next year, but the HABs attach themselves to the bottom of the water column and will likely re-emerge next year when the temperatures rise again. 

It is also worth noting while blooms didn’t appear at Windmill Cove this year, temperatures remained near 80° on the main stem of the San Joaquin River, and HABs were prevalent at Discovery Bay, Antioch, and Franks Tract. Sadly, our staff and interns were scheduled to participate in an Explore the Coast kayaking activity funded by the state with other young staff and volunteers from partner organizations. But they could not go kayaking in Stockton or Antioch due to HABS outbreaks, so the trips were canceled.

With blooms present at several testing sites, it was concerning to see people fishing, walking, having picnics, etc. Toxins from HABs not only affect humans but pets and wildlife as well. Fish in HABs-infested waters tend to have guts filled with toxins, which can be a method of exposure in subsistence fishers. Unsupervised pets and strays that ingest the water with toxins die from even licking the water off themselves. Communities living near Stockton’s waterways are also harmed when toxins from HABs attach to particulate matter in the air, compounding the air quality problem in Stockton.

While out sampling the waterway, people would always stop and ask why we are taking water samples or what the floating green colonies were, further highlighting the lack of awareness and appropriate warnings from local and state agencies. Stockton’s waterways have always been places where people congregate and recreate. Healthy places where city kids can interact with nature are worth protecting. The State Water Board needs to set standards for HABs in recreational water as opposed to only pursuing a drinking water standard.

Although Restore the Delta’s HABs monitoring program helped to raise awareness of the blooms we see each year in Stockton, more work needs to be done. The test strips we used were limited in effectiveness but helped diagnose the HABs. What we need now is the ability to consistently collect and send samples to labs for analysis to get quality data. This would require significant funding because that type of testing is costly. We also would like to get flow monitors put in place closer to the Port of Stockton to better understand how much flow moves in-land from the San Joaquin River. With more data, getting the State Water Board to set standards on HABs becomes much easier which will help address water quality issues in Stockton. We want to expand our testing program in Contra Costa County and the North Delta by training fishing groups and other community groups to begin sampling.

Funding isn’t the only way to help though. We are always looking for reports of bloom activity from the public. We are recruiting fishing groups and the public to report on possible blooms. That helps us target places to collect water samples that verify their reports. 

Contact information for reporting a HABs siting is provided below for Restore the Delta or the Water Board. We believe that the community can help us extend our reach and support our advocacy for a HABs standard to be set by the State Water Board to protect our surface waterways.

Are you seeing HABs in your region? 
Please contact us and the state.

Spencer Fern, Science Coordinator, Restore the Delta 
[email protected]
HABs Incident Reports (Water Board)

Delta Tunnel DEIS Report Public Comment Session in the Delta
December 6, 2022 (4 – 5:30 p.m.) 
In-Person meeting
The State of California is still pursuing a massive $16 billion+ tunnel that would severely impact the Delta without providing a single drop of new water.
Draft Environmental Impact Report (DEIR) comments on the Department of Water Resources’ controversial tunnel proposal are due December 16, 2022. It is critical to the future of the Delta for people to attend this meeting and make their voices heard. The meeting will provide a brief overview of the project and include an opportunity to put your comments into the formal record. Assistance with written comment submissions will be available. 

WHO: The Delta Legislative Caucus & The Delta Counties Coalition
WHAT: Public In-Person, in the Delta, Meeting
DATE: December 6, 2022 TIME: 4:00 p.m. – 5:30 p.m. 
PLACE: Willow Ballroom, 10724 CA-160, Hood, CA 95639

Friends, we need your help. 2022 has been action packed at Restore the Delta. In fact, we feel as if we have completed two years of work in half a year, and there is plenty more coming our way. Help us continue our fight. You can donate here.