Michael B. Bolger, Ph.D.

Toxicity Graph IF we had 35 CFS less flow in Summer of 2020

Peak Anatoxin-a Predicted to be in the "Danger Zone >70 ug/L"

Click here for a Periodic Blog on Observed Cyanotoxin levels and Factors that influence Russian River Toxicity

IMPORTANT DISCLAIMER: The prediction of anatoxin concentrations and the risk of toxicity to humans and animals presented on this web page should not be used to make decisions about personal safety or the use of Russian River recreation opportunities. These predictions are based on a simple mathematical relationship between river water temperature, river flow, and air temperature that will never be absolutely accurate. My intention for the publication of this model is to help the Sonoma County Water Agency and the Sonoma County Board of Supervisors to exercise adaptive management of Russian River flow and thus avoid the bloom of blue-green algae and potential river toxicity.

Sonoma County residents: Feel free to check this web site as often as you'd like to see the predicted Anatoxin-a concentration in Russian River. This simulation model does not provide specific geographical locations along the river for these predictions. The model uses daily river flow data from the gauge at Hacienda, water temperature at 3:00 PM in Guerneville. and air temperature also from Guerneville. If you'd like more detailed information about the equations used and background of the model development you can download the following report. Report on Water Quality, Draft EIR, and Simulation Model
Click here for a plot of the predicted change in daily anatoxin concentration
Please don't let the Sonoma County Board of Supervisors (SCBOD) ignore this easily avoidable and potentially life-threatening Russian River blue-green algae related toxicity! Encourage your supervisor and the Sonoma County Water Agency (SCWA) to adopt adaptive management of Russian River flows. Let's use an advanced computer model to predict when to expect a bloom of blue-green algae and the subsequent increase in cyanotoxin levels, and then adjust the river flow to easily avoid the potential toxicity.
Click here to see the historical predictions from 2015 to present.

NOTE: The water temperature (black line) has been divided by 10 so it can be plotted with anatoxin-a on the Left Y-axis.

My recommendation is for Sonoma County Residents to contact your supervisor and encourage them to instruct SCWA to utilize this type of simulation model to manage the Russian River flows when the conditions of flow, water temperature, and air temperature could give rise to this type of toxicity.
Here is a link to the Sonoma County Dept. of Health Services web page for current data on Blue-Green Algae and cyanobacteria:
SCDHS Blue-Green Algae. NOTE: when I checked on May 19, 2021 this site had a new report for the sampling results during the summer of 2020 (see below).
Here is a link to the State Water Resources Control Board (SWRB) web page for current data and a map of Blue-green algae and cyanobacteria outbreaks in California.
NOTE: As of June 7th 2020, the blue-green algae page on the SCDHS website has been removed. The link above will remain here assuming the SCDHS information will return later in the summer of 2020.
NOTE: As of June 25th 2020, SCDHS provided a notice that blue-green algae was observed in Salmon Creek Lagoon and that human sickness was reported. An observed value of 3 ug/L anatoxin on 6/25/2020 was added to the graph to note this event. Many areas of Clear Lake also had observed blue-green algae toxicity.
NOTE: On July 22nd 2020, SWRB web page reported the occurance of blue-green algae in Lake Ralphine (Santa Rosa). An observed value of 3 ug/L anatoxin was added to the toxicity model charts to mark this occurance.
NOTE: On August 17, and 27, 2020, the Sonoma County Health Department sampled several Russian River sites from Cloverdale to Monte Rio and reported that they did not find any evidence of a blue-green algae bloom or anatoxin-A concentration. However, on May 19, 2021 a downloadable file became available on the SCHD website for the year 2020 sampling results and several microcystin levels were reported in the Russian River for Camp Rose, Healdsburg, Johnson's, Monte Rio, and Patterson Point beaches.

Thanks, Mike
If you have questions, you can E-mail me at:

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