University of Vermont scientists studying Lake Champlain are assessing changes in water quality following recent flooding in Vermont.
Numerous rivers empty into Lake Champlain and scientists are measuring water clarity as floodwaters empty into the 100-mile-long lake. The Lake Champlain Basin Program and Lake Champlain Sea Grant hosted cruises on the University of Vermont research vessel recently for officials to observe a plume of turbid water extending into the lake.
Lake Champlain Sea Grant Associate Director and Extension Program Leader Kristine Stepenuck explained what to expect.
“We’re going to go onto our new hybrid research vessel called the Marcelle Melosira and we will head to the north,” briefed Stepenuck. “We’re going to do a couple of different things. Some of it is to hear from researchers. The other is to do two points where we will monitor water clarity to make a comparison between the main lake where we are now and up where the Winooski River is coming into the lake and see if we see a difference.”
Lake Champlain Basin Program Chief Scientist Dr. Matthew Vaughan talked about what is known about how flooding has affected lake water quality so far.
“The focus of today’s trip is of course on the flooding,” Vaughan reiterated. “So I’m here with some comparisons and some kind of quantitative information. It is very early and we’re still getting monitoring data coming in. So first of all, with any storm like this it starts with the rainfall. Last year in July it was a very slow-moving storm that parked over us and dumped 4 to 8 or even 9 inches of rain over a vast amount of area. And this year is very different. There were similar amounts of rainfall in some regions but it wasn’t quite as widespread and it was much more intense. And actually for the lake this event was certainly significant this year but not quite as much as last year. And that’s because of where the rain fell and how widespread it was.”
Lake Champlain Sea Grant Director and UVM researcher and professor Dr. Anne Jefferson noted that rivers moving sediment and wood is natural system behavior following a flood. She is studying plastic and microplastic pollution impacts.
"Because most plastic is floatable, right, it’s low density, it tends to be very mobile so any time water gets above the banks or higher up along the banks it will tend to remobilize any material that it has access to,” Jefferson said. “And so we suspect that an event like this would be a big mover of plastic pollution. We also are getting water into a lot of parts of the watershed where we don’t think about that cup or somebody’s Tupperware in their kitchen in a house that’s been flooded. Now this is plastic pollution that could be making it to the lake. So flooding with just its interaction with human infrastructure is potentially generating more pollution.”
Dr. Stepenuck interrupted Jefferson’s presentation as the Marcelle Melosira dramatically slowed.
“You notice the engine was cut,” Stepenuck said. “So you can see the plume coming out from the Winooski River. We can’t get too close because it gets too shallow for the draft of the vessel. But we can visibly see the difference in water clarity.”
Researchers onboard dropped a disc into the water to measure how far they could see it as the boat traveled through the plume. Vaughan noted that there are different methods of measuring water quality and determining the full impact of the most recent flood will take time.
“We have the long term monitoring program and the shortcoming of that is that it’s not very fast,” noted Vaughn. “We tend to get the data at the end of the season and we analyze it over the winter and we have results in the spring. So the most solid analyses we’ll have will be over the late winter and early spring next year.”
UVM’s Marcelle Melosira is the only research vessel in the world using a hybrid electric propulsion and winch system.
