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Cyanobacteria has already led to more Burlington beach closures than last year

A bloom of cyanobacteria, commonly known as blue-green algae, inundates the shore of Lake Champlain in this undated photo.
Vermont Department of Health
In 2023, Burlington's beaches have already surpassed last year's total number of days closed.

For Vermonters looking to escape the heat this summer, Burlington’s beaches have not provided much refuge. They and other Lake Champlain access sites have been periodically closed for swimming and other water activities since June. Many of these closures have been the result of cyanobacteria, or blue-green algae blooms.

To learn more, Vermont Public's Jenn Jarecki spoke to two city of Burlington employees: Erin Moreau, waterfront superintendent and harbormaster, and Megan Moir, division director of water resources. Their conversation below has been edited and condensed for clarity.

Jenn Jarecki: Can you start by explaining to listeners what exactly cyanobacteria is?

Megan Moir: It's an organism that has been around for years — many millions and millions of years. It's always there in the lake. Cyanobacteria can produce toxins, and that's why we're so involved in monitoring them and making sure that people have that information before they go to the beach. That's largely where Erin's work group is involved.

I think one thing that's special in Burlington, but sometimes makes it look like we have poor water quality, is the fact that we have such a robust monitoring program.
Megan Moir - Division Director of Water Resources, City of Burlington

Erin Moreau: Yeah, we know this is an organism that lives in freshwater and feeds on phosphorus and nitrogen. And we know that it has to play with the lake temperature. And so that's something that we monitor daily.

I wonder if one of you can contextualize for us how many algae blooms we're seeing so far this year.

EM: So as we sit here, in the beginning of August, we have had 39 days of beach closures here in Burlington, and that's various beaches within our system being closed. Well, if we look at last year, the entirety of the season, we had 32 total. So as we stand now, we are trending above where we were last year.

Megan, how can beachgoers be sure that swimming at these beaches is safe, even when they're open?

Megan Moir - Division Director - Water Resources, City of Burlington
Megan Moir
Megan Moir

MM: I think one thing that's special in Burlington, but sometimes makes it look like we have poor water quality, is the fact that we have such a robust monitoring program. The fact that Erin's staff are doing E. coli tests twice a week, I mean that those results are reported out and that they're also monitoring for cyanobacteria every single day, right? You could go to another place, and yes, there may be monitoring. But unless it's happening every single day during the swimming season, there could be blooms, there could be other conditions present that aren't necessarily getting documented and shared with the public.

Erin, what does the city of Burlington do to identify cyanobacteria and decide whether or not a beach is safe for swimming?

Erin Moreau - Waterfront Superintendent & Harbormaster, Burlington Parks, Recreation & Waterfront
Carmen George
Erin Moreau

EM: So we have two different types of monitoring that we do. We do cyanobacteria monitoring and we also do E. coli monitoring in two very different ways. The first one, cyanobacteria, that is daily and multiple times daily. So, our staff, again, is trained to learn how to identify a possible cyanobacteria bloom. And that is a visual test that anyone can be trained on, by the way. And so we monitor, visually monitor all of our beaches. And so we are at those sites daily. And like I said, multiple times a day. For instance, North Beach, our lifeguards are trained. And so they are in the towers from 11 a.m. to 6 p.m. daily. And so we have very good eyes on these beaches, where you know, we will close if we see it, and we understand that we may close more than other community areas. The other type of testing we do is E. coli testing. And that is done by water sampling. And we do that twice a week. So, we go out via the harbormaster boat on Mondays and Thursdays, and we sample at each location. The larger beaches get two samples on either end just to make sure that we are capturing that. And we provide that to the DPW lab — our friends here. And they will return that result within the following morning. And so that's done twice a week, unless there's an anomaly and we'll test it again.

Is it important that beachgoers also be able to spot it? And is there anything else they should be on the lookout for when heading to a beach or a water access area?

EM: Yes, informed citizens are powerful citizens, and educated citizens to make a good decision based on their well-being. The more you understand, the more you understand our recreational waters. You know, along with cyanobacteria blooms, anytime we get a large rain event that is pushing waters from our rivers into our lake, I always say 'Hey, there could be debris there, there could be logs in the water.' And so if you're recreational boating, because I do want to mention that as well, that there could be more debris in the water when we have had a flood event or high rain or snow melt off.

MM: I'm just gonna say that it's, you know, it is a very complex process. We don't know the exact formula for when blooms occur. And I know that can be disappointing to people for us not to be able to predict. But I think the thing to know, what we try to convey, is like, we are doing our part both in managing the immediate issue of collecting information and making sure swimmers have information at their fingertips to make choices. And then it's a little bit more behind the scenes but my staff really is trying to put the pieces in place to make sure that we're turning off the faucet of phosphorus from Burlington.

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