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CELINA - A two-person team that is essential to Grand Lake's ongoing water quality improvements was honored on Saturday with the Lake Improvement Association's Guardian of the Lake Award.
"Today is a little different," LIA Trustee and county commissioner Brian Miller said at Saturday's LIA meeting. "Today, we are presenting the award to a team. None of you are going to be surprised as to who is on the team, but many of you are going to be saying to yourself, 'It's about time.'"
This year's Guardians of the Lake are Stephen Jacquemin, an environmental sciences professor at Wright State University-Lake Campus, and Mercer County agriculture and natural resource director Theresa Dirksen.
The Guardian of the Lake honor is commonly bestowed to one person who has taken extraordinary action to improve Grand Lake. The duo did this by working together; blending science, engineering and project management to make a massive impact to Grand Lake, Miller said.
"(LIA President) Brian Morris recently said, 'If anyone else was in either of their positions, I am confident we wouldn't have seen anywhere near the progress we have made,'" Miller said.
Dirksen has multiple roles in relation to Grand Lake. One is her title as ag and natural resource director, in which she engineers and provides project management to the lake's treatment trains and other watershed-related practices. In addition, she spearheads the Lake Restoration Commission and works closely with the Lake Facilities Authority.
Jacquemin has studied the lake for well over 10 years, and is "all about science, research and evidence-based solutions," Miller said.
In addition to teaching at Wright State Lake Campus, he monitors the lake as a research coordinator, has been published in numerous major scientific journals and has conducted numerous research studies on Grand Lake.
"If Grand Lake is the poster child for toxic algae blooms, then Dr. Jacquemin is writing the playbook blueprint for how to solve it," Miller continued.
After the award presentation at Saturday's meeting, LIA members heard some major lake updates from Jacquemin.
Grand Lake had an "unbelievably low-flow year" in 2025, as the area experienced a massive drought, he said.
"It depends on what area of the state you're looking at, and what gauge you're looking at, but it's not a stretch to say that the amount of precipitation we've received this year is among the lowest we've seen even in the last century," Jacquemin said. "Here in Grand Lake St. Marys, the only month that we had somewhat normal stream flows was the month of April. It was fairly normal, maybe even up a few percent ticks, but that was it. Every other month was down quite a bit."
It wasn't just the rain totals that were down in 2025, he said, but also the rain's timing was off.
"A lot of the rains that we did get ended up sort of soaking into the earth and not really running off, because when it did rain, it was raining on really dry ground," he said. "We had some months that were up to 80% less as far as daily stream flow. On average we were down about 55% or so in terms of our daily flows."
A very large fraction of the stream flow that did make it into Grand Lake was picked up by its main wetlands and filtered. In 2025, 757 million gallons of water were processed through Grand Lake's wetlands.
"This is up from last year. Last year, we were at about 620 million gallons. The year before that we were at about 440 (million gallons of water treated)," Jacquemin said. "This is a very positive trajectory."
The lake's four main wetlands are Prairie Creek, Coldwater Creek, Beaver Creek and Big Chickasaw.
Prairie Creek and Coldwater Creek both treated 15% of all stream flow, 3.5% of Beaver Creek's streams were processed, and at Big Chickasaw, 4-5%.
"These are big percentages, big fractions of those creeks," he said. "Our field and lab observations from this year, they've continued to demonstrate that these wetlands - as long as they're managed and we look over them - these wetlands continue to be nutrient and sediment sinks. They continue to improve water quality."
A full annual fact sheet is still being completed by Jacquemin and his team, which will include the pounds of nitrogen, dirt and phosphorus the wetlands pulled out in 2025.
"We are in the late stages of sort of concatenating all of that data together. We will have the full annual fact sheet and report for 2025 at the February (LIA) meeting," he said. "The next time that we see each other, that report will be in your hands."
The lake's algal community experienced a good year, Jacquemin said.
The lake's weekly toxin levels averaged at about 27 micrograms per liter all year, which is about 41% lower than historical averages. Its spring average was about 20 micrograms per liter, around 60% lower than historical averages; its summer average was about 26 micrograms per liter, about 42% lower than historical averages; and its winter average was around 2.1 micrograms per liter, nearly 86% under the historical average.
"When we look at where we're at as far as the benchmarks for the World Health Organization, or the State of Ohio's benchmarks or the federal EPA's benchmarks, we were only above the WHO average only about 17 weeks, and a couple of those weeks were just on it," he said. "They were just flirting with that (benchmark), they were never really massively above that except for a couple of weeks. We only had a couple of weeks this year that were what I'd consider to be kind of egregiously high."
Every year the lake experiences an improved water quality, that historical average of toxin levels becomes harder to reach.
"Yet we keep doing it. We keep getting better and better and better," Jacquemin said. "If we were to compare 2025 to say the worst couple of years on record - say 2014, 2015, 2016 - we wouldn't be 60% less for spring values, we'd be closer to 90-95% less. When we look at these improvements, we are looking at an average of the good years and the bad years, and we're still meeting those improvement goals better than the average. That's our goal every year: just be better than the average."
Grand Lake's water quality improvements took a large amount of effort, from a large amount of people, he added.
"This is a communitywide effort, and I appreciate the role everyone plays in that. There can't just be one person - it's a lot of people involved," Jacquemin said. "Unfortunately, we don't get to recognize every single person involved in all of this every single week. I wish we could. But, there's a lot of people involved, and I'm looking forward to seeing what the next year brings."
