by

Michael B. Bolger, Ph.D.

Click here for Predicted Daily anatoxin concentration

Periodic Blog on Russian River Low Flow Toxicity (July 2017 to present)

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.

October 7, 2024:
Sonoma County/Russian River residents: There was a slight uptick in the predicted levels of Anatoxin toxicity during July of 2024. However, overall the river has been looking good for all the summer of 2024.

May 13, 2024:
Sonoma County/Russian River residents: The Russian River has been looking good for the winter of 2023/2024.

July 23, 2023:
Sonoma County/Russian River residents: The Russian River has been looking good for the last 20 days.

July 3, 2023:
Sonoma County/Russian River residents: I have now updated all the graphs of potential anatoxin toxicity in the Sonoma County Russian River for Guerneville, CA area from Sept. 2022 to July 2023. At the current time the river is flowing nicely ~150 cfs and the anatoxin model does not predict any toxicity. Sonoma County Dept. of Health decided to post warning signs at all of the popular Russian River beaches rather than expose the actual measurements of harmful algal blooms for 2021 and 2022. Last year the Sonoma County Water Agency lowered the flow near Guerneville to ~35 cfs and the anatoxin model predicted some very high levels of blue-green algae toxicity. So far this year the higher flow and relatively cool water temperature have reduced the risk of toxicity but the river is full of normal algae and the turbitity is high. Normal turbidity in Sept. 2022 was ~1.5 nephelometric units. Currently the turbidity is up to 8.0 nephelometric units. We'll keep an eye on this and provide another graph if it gets worse.

February 11, 2023:
Sonoma County/Russian River residents: Last September, I reported that a suspected illness was reported on the Calif. State Water quaility HAB website (see link from Sept. 3rd 2022 below). If you check that link today, almost all reports about the Russian River in 2022 have been removed and the Sonoma County Dept. of Health do not post their measured HAB results for 2021 or 2022. Fortunately, I took a screen shot of the Calif. State HAB website on Sept. 3, 2022. Please see the last sentence of the Report Details and notice all of the other Russian River HAB reports from the State website in Sept. 2022.

I was not able to find any followup reports about the suspected illness at Johnson's beach that I recorded on Sept. 3, 2022.

September 3, 2022:
Sonoma County/Russian River residents: The anatoxin-a concentration model continued to climb in August and on Aug. 24th the Calif. State Water quality HAB website reported that a suspected illness was reported at Johnson's Beach on the Russian River. The reported illness is under investigation by the Interagency HAB-related Illness Workgroup. No determination has been made at this point. Fortunately, the Sonoma County Water Agency increased the flow by ~20 cfs (its now between 55 and 60 cfs) and lowered the water temperature to 71 deg. F. Hopefully, these steps will help to minimize the toxicity.

July 22, 2022:
Sonoma County/Russian River residents: As you can see on the graphs (see link above), the Russian River has continued to warm (temperatures up to 75 deg F) and the flow has continued to decrease (down to 32 cfs). As reported in the Santa Rosa Press Democrat on July 20, 2022, these conditions resulted in the observation of blue-green algal mats below Monte Rio at Patterson Point and nine other locations upstream to Healdsburg as reported July 19th on the State Water Resources Control Board (SWRB) web page. My family and others we've talked to along the Russian River have reported the observation of more than the usual number of leeches attached to their legs after wading in the shallow warm water along the shore of beaches. In my opinion, all of these consequences are the result of climate change and could be reduced by increasing the flow.

June 26, 2022:
Sonoma County/Russian River residents: The flow in the Russian River at Hacienda has already been reduced to 56 cfs and the water temperture is up to 77 deg. F. These are conditions that are ideal for the bloom of Blue-Green algae and the production of Anatoxin-a. Unfortunately the Sonoma County Dept. of Health has not posted additional results of their measurements in 2021. One measurement for Aug. 3rd 2021 was 8.36 ug/L which is slightly above the safe level for short time exposure in drinking water. The Anatoxin model results from the summer and fall of 2021 suggest that the lower Russian River was exposed to much higher levels of Harmful Algal Blooms (HABs) and Anatoxin-a concentrations. Already this year the model briefly hit a level of 8.8 ug/L.
I compiled a video of a North American River Otter family who lived in the Russian River near Guerneville. We observed them from 2017 to 2021. However, the drought in Northern Calif. required that the Sonoma County Water Agency reduce the river flow near Hacienda to only 35 cfs. This caused the bloom of duckweed, Ludwigia, and blue-green algae in the summer of 2021. The river otter video documents some of the sightings of river otters and the results of low flow. As of June 2022 the otters have not returned. Please encourage the Supervisors to instruct the Sonoma County Water Agency to review these predictions and increase the river flow when a bloom is highly likely.

September 25, 2021:
Sonoma County/Russian River residents: We've had a very hard summer in the Lower Russian River with average river flow in September 2021 of 41 cfs. This has resulted in extreme growth of the invastive plants "duckweed" and Ludwigia. In addition, as you can see from the graphs on this website the predictive model of anatoxin-a in the Russian River has climbed up to 124 ug/L and has finally reached a plateau. The plateau level is a result of lower water temperatures and slightly higher river flows. The Sonoma County Dept. of health last reported a measured level of anatoxin-a = 8.36 ug/L on August 3rd 2021 and has not posted any additional measurements since then. However, measurements of blue-green algae toxicity (microcystins) in Clear Lake in September have exceded 4,000 ug/L. This is a danger level of toxicity that can result in sickness and death in fish, wildlife, and humans. Unfortunately, we are between a rock and a hard place on this subject. The harmful algal blooms (HABs) could easily be reversed by increasing the river flow but the drought and lack of water conservation along with continuing housing development requires that the Sonoma County Water Agency maintain a low flow to prevent Lake Mendocino and Lake Sonoma from running dry. I support the Russian River Watershed Protection Committee (RRWPC)'s call, (Please see for the Sept. 2021 Newsletter), for increased water conservation and higher minimum flows in the lower Russian River.

August 9, 2021:
Sonoma County/Russian River residents: Well I hate to say I told you so...
This morning I added the latest flow, water temperature, and air temp. data to the model spreadsheet and I read in the Sunday 8/8/2021 Press Democrat that the Department of Health Services posted new measurements of anatoxin-a at five different unspecified locations on the Russian River. The highest anatoxin-a concentration was 8.36 ug/L which is the highest reading since September of 2015. I'm not surprised by these results even though I posted a discouraging comment on August 3rd (see below) before the latest measurements were made public. Clearly, the model predicts higher concentrations of anatoxin-a than were measured. But the most important factor is that the model warned of this outcome over a month ago. There has been plenty of time for the Sonoma County Water Agency (SCWA) to increase the flow to prevent this bloom of blue-green algae. So far we have not heard any news of adverse health consequences but if the Supervisors do not direct Grant Davis (manager of SCWA) to increase the flow, I suspect it will only be a matter of time till we hear about sickness in dogs and wildlife.

August 3, 2021:
Sonoma County/Russian River residents: The anatoxin-a prediction model continues to forecast rising levels of toxicity between July 4th and August 2nd. However, the county Dept. of Health and the State HAB websites do not report any additional observations of blue-green algae blooms or water toxicity. There is a common saying in the modeling and simulation community. "All models are wrong but some are useful". In this case, if the predictions of toxicity prove to be a gross overprediction, then this model may not even be useful.

July 4, 2021:
Sonoma County/Russian River residents: The anatoxin-a prediction model continues to forecast rising levels of toxicity between June 20th and July 10th. The Sonoma County Dept. of Health still has posted "Check for Algae" signs at several beaches along the Russian River. Their website does not show the results of new testing conducted July 8th at Alexander Valley Campground, upstream of Riverfront Park in Windsor, and upstream of Steelhead Beach. However, the good news is that according to the Calif. State HAB website, no cyanotoxins were detected at those sites on July 8th even though the anatoxin-a model predicted levels above 20 ug/L. According to my own observations the Russian River visibility at this time is much better than in previous years. Perhaps this is due to less runoff from farms due to water supply cutbacks.

July 4, 2021:
Sonoma County/Russian River residents: Happy Fourth of July! I'll make the blog entry short so we can get back to family fun. The anatoxin-a model is not a true prediction because the input parameters are the recorded Russian River flow, water temperature at 3:00 PM, and daily high air temperature. However, the basic model has not changed since 2016 and the model estimates anatoxin-a concentration long before the measured values are posted on the state or county websites. Consequently, the model can be considered a "prediction" since it was trained in 2016 and does not include data on measured levels. The current prediction shows that the lower flow and moderately high water temperature will result in significantly higher anatoxin-a concentration and harmful algal blooms (HAB)s. The predicted level is currently 14.5 ug/L and its headed up to 20 ug/L which is a Tier 1 warning level. I recommend that the Sonoma County Dept. of Health conduct more frequent testing and reporting. Currently many of the Russian River beaches are posted with warning signs that ask the public to "Check for Algae" and if you see HAB then don't let children or dogs touch, eat, or swallow the algal mat. This seems like a silly warning because very few members of the public are able to recognize HAB mats. The county does not seem to want to institute mandatory conservation of water and to increase the Russian River flow to avoid this type of toxicity. Its going to be an interesting summer.....

June 24, 2021:
Sonoma County/Russian River residents: This is my first post of the year but I'm sure it won't be the last. On June 14, 2021 the State Water Resources Control Board, Division of Water Rights approved a request from the Sonoma County Water Agency (who controls the outflow from Lake Mendocino) to allow the lower Russian River to have flows as low as 35 cfs. If you have any questions about this policy, please contact Jane Ling by email at jane.ling@waterboards.ca.gov. On the very same day as this approval, the results of testing from 10 locations on the Russian River showed anatoxin-a concentration at 0.15 ug/L and signs were posted at many beaches along the Russian River.

Unfortunately, this was not unexpected. The predicted anatoxin-a concentration for the Russian River moved into a positive range in mid May and again on June 10th 2021. Currently, the river flow is as low as it was in 2015 and the anatoxin-a model derivative is higher than ever before. A derivative plot shows the predicted change in anatoxin levels. On August 1st 2015 the model predicted its highest derivative change value until now. This was a positive 1.39 ug/L change in anatoxin due to three days of river flow less than 60 cfs with water temperature ~75 deg F. The river flow is now down to 57 cfs and the water temperature is up to 76 deg F and the derivative value is up to 1.56 with predicted concentration of 3.7 ug/L. Now is the time to contact your supervisor and also Mr. Grant Davis, Manager, Sonoma County Water Agency, 404 Aviation Boulevard, Santa Rosa, CA 95403-90919 Grant Davis and implore them to increase the river flow before the blue-green algae has a chance to grow more rapidly. I have included a prediction of the anatoxin-a concentration based on the observed flow and temperatures from 2020 but assuming the flow was decreased by 35 cfs. The prediction plot (Click here to see a blowup) shows a devastatingly high level of toxicity.

Dec 10, 2020:
Sonoma County/Russian River residents: I don't know about you but I feel much better about everything. I've been practicing meditation and mindfullness which greatly helps to keep me calm and let things wash over. We have a vaccine, new president, and no Russian River toxicity. I posted an update for the graphs of river flow and air and water temperature from Sept. 26th to Dec. 9th. The river is cold and everything looks OK. I hope we get some good rain but not so much as to cause flooding. All the best to you and your families.

Aug 30, 2020:
Sonoma County/Russian River residents: The anatoxin-A toxicity model prediction flucuated up and down from zero to a slighly positive estimate during the last half of June and all of July and August. This was the result of higher summer water temperature and flucuating flow in the Russian River. The lowest flow of the 2020 summer (76 cps) occured on August 16th when the model derivative turned upward toward a significant positive trend. Subsequently, Sonoma County Water Agency increased the flow and the anatoxin-A daily estimates dropped back to zero. Sonoma County Health Department sampled several Russian River sites from Cloverdale to Monte Rio on August 17th and 27th and did not find any evidence of a blue-green algae bloom or anatoxin-A concentration. This is good news for the Sonoma County residents who are interested in the quality of water in the Russian River. On a personal note, I'd like to thank all of the first responders (particulary the fire fighters) who battled the Walbridge fire. The service of those first responders literally saved my house in Guerneville. I am sad, and send best wishes to all of those who were not so fortunate.

July 31, 2020:
Sonoma County/Russian River residents: The anatoxin-A toxicity model prediction was in positive territory during the last half of June and all of July. This was the result of rising water temperature and lower flow in the Russian River. The State Water Quality Board web site reported the occurance of blue-green algae in Lake Ralphine (Santa Rosa, CA) on July 22nd. During the last week the model derivative started to become negative due to an increase of river flow up to 115 cfs on July 27th. At this time the anatoxin-A prediction model has become less than 1 ug/L. This is very good news and may indicate that the Sonoma County Water Agency is using adaptive contol of river flow to avoid the risk of additional toxicity.

July 18, 2020:
Sonoma County/Russian River residents: In the last few weeks we've had some nice hot weather creating warmer water temperatures (up to 75 deg. F on 7/11/2020) and flow decreasing from 99 to 87 cfs on the same day as the high water temperature. The Russian River Low Flow model moved into a positive derivative space in late June resulting in predicted levels of anatoxin-A as high as 2.6 ug/L on the fourth of July. We also had blue-green algae caution signs posted in Salmon Creek Lagoon near Bodega Bay on June 26th 2020. The State Water Resources Board (SWRB) advisory states "Stay away from algae and scum in the water. Do NOT let pets go in the water, drink the water, or eat scum on the shore. Keep Children away from algae. Do not eat shellfish from this waterbody." and that "Lab testing of water and mats confirmed presence of dense cyanobacteria HAB in the lagoon and low levels of microcystins and cylindrospermopsin were detected in mats." The SWRB report also stated that "A human illness was reported after swimmming and recreating at the lagoon."
We don't know if the Sonoma County Department of Health Services (SCDHS) has been testing the Russian River yet this summer. Obviously, the concerns about the CoVID-19 pandemic are much more serious than low levels of anatoxin-A in the Russian River and the Supervisors have much to deal with in addition to Russian River toxicity.
As long as the Sonoma County Water Agency (SCWA) maintains the flow >85 cfs we probably won't have to worry about high levels of blue-green algae toxicity. However, On June 8th, the SCWA submitted a Temporary Urgency Change Petition (TUCP) to the SWRB asking for a change in their water rights permits to allow for lowering minimum flows in the lower river from 85 cfs to 70 cfs and later possibly as low as 40 cfs. In my opinion this would be a disaster for the lower Russian River. River flow at 50 cfs resulted in very high levels (45 ug/L) of anatoxin with several dog deaths and some human sickness. River flow of 40 cfs would probably be even worse.
As a test of this scenario we simulated the influence of 40 cfs from July 1st to July 16th and the predicted level of anatoxin-A reached 20.2 ug/L with a positive derivative of 2 ug/L per day for as long as the low flow continues. Please keep watching this web page for updates during the summer of 2020.

June 23, 2020:
Sonoma County/Russian River residents: The Russian River Low Flow model of predicted anatoxin levels will be updated more frequently. We've had some relatively warm weather resulting in river water temperatures up to 76.5 Deg. F on June 4th. Fortunately, the flow has been relatively high (not less than 100 cfs until recently). Unfortunately, the flow has decreased to 82 cps and the anatoxin toxicity model has moved into positive values every day since June 14th. This is not a good sign for river toxity. At the MAC meeting on June 18th, Linda Hopkins reported that the Sonoma County Water Agency (SCWA) plans to petition the North Coast Water Quality Board to be able to reduce the flow to 40 cfs due to an expected extremely dry summer. As you can see the toxicity model has moved into positive values with flow reduced to only 88 cps. This is VERY ALARMING!! If the low flow of 40 cfs is combined with high water temperature we will be guaranteed to have high levels of blue-green algae and anatoxin toxicity in the summer of 2020. Please keep you eyes on this website during the next few months and contact your supervisor and SCWG to consider adaptive control of the flow to avoid a repeat of the toxicity and animal deaths seen in 2015.

June 7, 2020:
Sonoma County residents: The Russian River Low Flow model of predicted anatoxin levels has been updated with data from the winter and spring of 2020. We've had some very warm weather resulting in river water temperatures up to 77.5 Deg. F on May 27th. Fortunately, the flow has been relatively high (not less than 100 cfs) and the anatoxin toxicity model has not moved into positive values yet. However, the flow has been decreasing every day since May 19th. Linda Hopkins reported to our lower Russian River MAC group that the Sonoma County Water Agency (SCWA) plans to reduce flows this summer to ~50 cfs. That type of low flow combined with high water temperature resulted in high levels of blue-green algae and anatoxin toxicity in the summer of 2015. Please keep you eyes on this website during the next few months and contact your supervisor and SCWG to consider adaptive control of the flow to avoid a repeat of the toxicity and animal deaths seen in 2015.

August 3, 2019:
Sonoma County residents: The river flow is still higher (148 cfs) than normal (normal flow = 80 to 90 cfs) for this time of year. In spite of the higher water temperature (77 deg. F on 7/28/2019) the anatoxin-a predictive model does not estimate a bloom of blue-green algae and does not estimate the production of anatoxin. The SCDHS web site does not report any measured levels of blue-green algae toxins yet this year. Its all good news.

July 21, 2019 -- First report for 2019:
Sonoma County residents: Its a new summer and I will again be updating the graphs that estimate the risk of Russian River toxicity from blue-green algae and Anatoxin-A.This year many of us had to deal with floods during the winter. I know because I mucked out, dried out, and repaired and restored paneling and insulation for two homes in Guerneville. The good news is that the dams are full and we've had relatively high flow in June and most of July. Consequently, even with the high temperatures last week the calculated risk of Anatoxin polution is very low. However, you will see on the "derivative" graph that the negative trend in Anatoxin production is getting less negative each day. Last August the model shifted into a low positive prediction just a few days after the "derivative" (or expected change per day) was -0.361. Last year at about the same time in August there was an observation of microcystin in Forestville and Steelhead Beach. Microcystin is another toxic product of blue-green algae. As of today the "derivative" is -0.480 and the trend is moving to less negative values. We're expecting hot weather next week and the flow is getting lower so keep your eyes on this web site for daily updates.
NOTE: The Sonoma County Department of Health Services (SCDHS) has reported that "Mercury has been detected in fish from the Russian River". They recommend that you consume fish only after removing guts and liver, and rinsing fillets in clean water. Additional guidance regarding mercury in fish and be obtained from: Mercury in Russian River Fish. Unfortunately, if you read the report closely you'll see that the mercury measurements were conducted between 1979 and 2015. There are no results from this spring 2019. We know that the flooding in February caused a breach of a gravel pit with mining waste Polluted Gravel Pit Breached During Flood. That incident probably released "mining waste containing Mercury, Iron and Aluminum at 200-800% of safe levels and Phosphorous at almost 500 times more than levels that can trigger toxic algae". I'd recommend that SCDHS do some additional sampling of fish from the Russian River in order to update the results of mercury levels.

September7, 2018:
Sonoma County residents: I have now confirmed with the Sonoma County Department of Health that they did not conduct sampling in the month of July 2018 until the 30th. Consequently, the observed levels are zero even though the predicted levels are significant.
September 1, 2018:
Sonoma County residents: I apologize for my delay in doing the latest calculations and posting the results. I'm sure its been a very busy summer for all of us.
So far the summer of 2018 has been practically free of anatoxin-a and other blue-green algae toxins. However, in August, the SCDHS reported low levels of microcystin on the 6th, 13th, and 19th at Camp Rose and Steelhead beaches. Also, there was a recent low level positive test report for anatoxin-a at Johnson's beach on Aug. 20th. It appears that the downloadable SCDHS 2018 Toxin Test Results include only the days that were tested with a positive result. We don't know when the testing started and if there were days of testing in July and August with no observed levels. In the last two weeks the river flow has been increasing and that will help to prevent a bloom of blue-green algae in September.
Nota bene: I just created a new graph that shows a blow-up for just the Summer of 2018 I had to divide the water temperature by 10 so it can be plotted on the same Left Y-axis as the anatoxin-a concentration. But now you can see the predicted and observed toxin levels more clearly for the current year.
Please enjoy your Labor Day weekend!
July 23, 2018:
Sonoma County residents: As I reported last week the conditions have been right for a bloom of blue-green algae and last week the predictive model showed a low level of 3.3 ug/L. In fact the Sonoma County Department of Health Services (SCDHS) has now reported an "Algal Bloom at Riverfront Regional Park: Although they do not monitor the lakes at Riverfront Regional Park near Windsor, visual inspection by a water expert indicates the presence of potentially harmful algal blooms in Lake Wilson." The predicted change in the anatoxin-a model equations moved into a negative range this week due to continued good flow (~92 to 110 cpf) and there is no longer a positive prediction level. I assume that the SCDHS has resumed testing in the main Russian River since they reported "Please note, currently there are no restrictions along the Russian River."
July 16, 2018:
Sonoma County residents: At the beginning of July, the anatoxin-a prediction model moved toward a warning of a low level (3.3 ug/L on 7/6/2018) of anatoxin-a for the first time this year. This estimate is due to the high water temperature (75 deg. F) and lower river flow (~75 cfs). I can't tell if the Sonoma County Department of Health has started to test for anatoxin-a yet. The State trigger level to post warnings is "any detected" and the warning level for anatoxin-a is 20 ug/L. So if the model estimate is correct but the county has not started testing, then we are still 10 times lower than the official State warning level. I did see that right after the hot spell the water flow was increased from 75 cfs to ~100 cfs which helps to dilute the anatoxin and reduce water temperature. As of today the model is still predicting ~1 ug/L so I'll try to make more frequent updates to the web site.
June 24, 2018:
Sonoma County residents: As the Russian River water temperature rises, the river flow decreases, the dams go in, and people flock to the river on hot days, it becomes more important to have many methods to evaluate the risk of toxicity to humans and animals. Therefore, I am providing this public disclosure of a model that specifically predicts the concentration of anatoxin-a in the lower Russian River. My primary purpose is only to inform the Sonoma County Water Agency and the Board of Supervisors of potential risks of toxicity so that they will consider increasing the river flow to prevent the bloom of blue-green algae and lower the concentration of toxins.
Beginning the week after Memorial Day, the Sonoma County Department of Health Services (DHS) works collaboratively with the North Coast Regional Water Quality Control Board (NCRWQCB) to provide river condition information. Data on water temperature and flows as well as visual monitoring (algal mats, stagnation, etc.) is reviewed and evaluated weekly basis. When conditions are favorable for the growth of blue-green algae (aka cyanobacteria), laboratory sampling for cyanobacteria toxins will begin. Once initiated, water sample testing will be performed at 10 public beaches along the Russian River. If toxins are detected at a level above the thresholds established by the 2016 California Cyanobacteria Harmful Algal Bloom Network Guidance, DHS will issue public notifications and post signs at the beaches.
The DHS response and public warning comes only after the observation river toxicity. I have proposed to all of the relevant agencies (SCWA, BOD, DHS, and NCRWQCB) that utilization of a simple computer model of anatoxin-a concentration would allow them to adopt adaptive responses to the threat of river toxicity and simply increase the flow of water in the river to prevent the toxicity.
We are now starting a new summer after a year of relatively little rain and after the devastating fires in Sonoma County. There will be increasing political and economic pressure to conserve water for new housing developments that are served by SCWA (east of Mirabel). It will be incumbent upon us (Sonoma County Residents) to continue asking our leaders to help protect our most valuable natural resouce, the Russian River.
Sept 24, 2017:
Sonoma County residents: As of September 11, 2017 there was no measureable amount of anatoxin-a in the Russian River. (Sonoma County Dept. of Health Services Blue-Green Algae). Flow is still high, water temperature is lower, and air temperature is normal. All of these parameters tend to inhibit the growth of blue-green algae. This will be the last blog entry for the summer of 2017. Today I'm pulling my little green sailboat out at Johnson's beach. The dam at Johnson's beach comes out Sept. 30th. Hope you have a great winter.
Aug 29, 2017:
Sonoma County residents: As of August 21, 2017 there was no measureable amount of anatoxin-a in the Russian River. (Sonoma County Dept. of Health Services Blue-Green Algae). Flow is high, water temperature is lower, and air temperature is high. All of these parameters tend to inhibit the growth of blue-green algae. This will be the last blog entry for the summer of 2017 unless conditions change dramatically.
Aug 18, 2017:
Sonoma County residents: As of August 14, 2017 there was no measureable amount of anatoxin-a in the Russian River. (Sonoma County Dept. of Health Services Blue-Green Algae). This is good news and is probably due to the drop in river temperature and the maintenance of flow > 100 cfs. That is all for today. I'm going to take a swim in the River.
Aug 6, 2017:
Sonoma County residents: On July 31st 2017 a low level (0.25 ug/L) of anatoxin-a was reported at Johnson's Beach in Guerneville (Sonoma County Dept. of Health Services Blue-Green Algae). In addition, a low level of anatoxin-a was reported at Steelhead Beach (0.16 ug/L). These levels are 100 times lower than the State of California Warning levels so there is no need for alarm at this point. In spite of the high river water temperature, the predictive model for anatoxin-a has not moved into a positive region of change yet (Click here for a plot of the predicted change in daily anatoxin concentration). However, the model had one of its lowest negative derivative values (-0.49 ug/L/day). A negative value means that anatoxin-a is not predicted to build up with the current conditions. If the derivative value becomes positive we might expect anatoxin-a concentration to increase on a daily basis. The negative derivative value is mainly due to the fact that the river flow is still above 100 cfs. The flow was down to 126 cfs on July 29th but had increased to 146 cfs by Aug. 2nd. This change in flow might be normal variability or it might reflect adaptive control by the Sonoma County Water Agency. If anyone reading this blog knows if SCWA increased the flow in response to the measured anatoxin-a please let me know by sending Email to the address listed below. I will continue to update this blog on a periodic basis and attempt to keep the public informed about changes in the predicted risk for toxicity.
July 25, 2017:
Sonoma County residents: On July 24th 2017 we saw the first reports of measureable levels of anatoxin-a in the Russian River (Sonoma County Dept. of Health Services Blue-Green Algae). The following sites had very low levels of anatoxin-a: Cloverdale River Park Beach (0.16 ug/L), Del Rio Woods Beach (0.15 ug/L), and Patterson Point (0.14 ug/L). These levels are 100 times lower than the State of California Warning levels so there is no need for alarm at this point. In spite of the high river water temperature, the predictive model for anatoxin-a has not moved into a positive region of change yet (Click here for a plot of the predicted change in daily anatoxin concentration). This is mainly due to the fact that the river flow is still above 100 cfs. The water temperature near Guerneville spiked to 77 deg. F in late June but the river flow was high enough to lower the risk of anatoxin production. I will continue to update this blog on a periodic basis and attempt to keep the public informed about changes in the predicted risk for toxicity.

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.

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
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.

Thanks, Mike
If you have questions, you can E-mail me at: labsoft@comcast.net

Traffic Counter