A new recreation facility, strong tourism, and ongoing water quality progress. 2025 was another excellent year for Grand Lake as we continued to see improvements across the board. Community support is crucial to our cause, and the Lake Improvement Association applauds the efforts of the many people and organizations who contribute to make our lake an economic engine, wildlife sanctuary, and recreation hub for all who enjoy its waters and shores. This year in review recaps 2025 lake improvement highlights.
The LIA extends a special thank you to the following individuals who contributed to our year in review – and for all their efforts to improve and promote Grand Lake St. Marys:
Courtesy Dr. Stephen Jacquemin
Lake conditions relative to algal biomass and microcystin toxins continued to be low this year compared to historical averages.
2025 seasonal total microcystin toxin concentration (ugL) averages compared favorably to historical (2009-2024) data:
Seasonal averages for spring and winter were well below the World Health Organization (WHO) threshold for recreation (24.0 ugL) whereas while Summer and Fall were technically above, they were closely approaching this advisory level. Note that across all weeks in 2025 only 17 weeks (out of 52) were higher than the WHO benchmark limit.
2025 was an extremely low flow year apart from April. Average daily stream flows across all months were down approximately 53% with some as much as 80% less flow than historical averages. Extending discharge to load – this meant that much of 2025 experienced lower than average loading (we saw similar things in 2023 and 2024). Long term analyses to update watershed level findings are continuing to carry over from 2025 into 2026.
Well over 1,000 acres of wetland restoration have been undertaken over the past decade – 2025 continued this trend with such new wetlands as Redwing Nature Preserve being completed on the north shore of the lake this year with numerous plans to continue wetland habitat restoration projects in and around the watershed for next year.
Wetland monitoring data continued to demonstrate that the GLSM wetlands are a sink for nutrients and sediment with up to 90+% nutrient/sediment concentration reductions compared to in-stream concentrations during many weeks of the year.
In all, a total of approximately 757 million gallons of water was treated this year representing a cumulative total (as of November of this year) of 14% of all Prairie Creek flows, 14% of all Coldwater Creek flows, 3% of all Beaver Creek flows, and 4% of all Big Chickasaw Creek flows.
Courtesy Theresa Dirksen
The Redwing Nature Preserve sits on just over 16.5 acres of land that was acquired by the Grand Lake St. Marys Lake Facilities Authority in July of 2024. This land had been formerly marked for residential development and sits on the north side of the lake directly adjacent to the Grand Lake St. Marys State Park between State Route 703 and Edgewater Drive in Auglaize County. Earthwork began in September 2025 on the many wetland pools added to the project site.
The main project area consists of approximately five acres of wetland that will treat water pumped from the lake. It is estimated that about 400,000 gallons of water per day during the growing season will be treated before being released back into the lake. The western side of the property includes another 1.5 acres of wetland that will treat medium and high flows from a small channel draining into the lake from the north. The site has been seeded to native cool-season grasses, forbs and wetland vegetation.
Discussions are ongoing about how to best extend the existing Redwing Nature Trail from the State Park over to this new treatment wetland.
The construction of this project was funded by the H2Ohio program through the Ohio Department of Natural Resources. (Photo taken October 20, 2025)
In June of 2025, the Grand Lake St. Marys Lake Facilities Authority acquired just over 50 acres of cropland and woodland near the southeast corner of the lake at the intersection of Koehn and Schroeder Roads. The project site includes 34 acres of cropland, approximately 6 acres of forest and the remaining land is scrub/shrub area due to former development activities.
The intent for this site is to construct a series of treatment wetlands to trap nutrients from water pumped from Barnes Creek prior to being released into the lake. The estimate to complete this project is nearly $1.5 million, and several grants are being sought to potentially fund this project. Construction is anticipated in the summer of 2027 if funding is successfully secured. A project concept is below.
In the summer of 2025, a new website was launched, www.grandlaketrails.com. This site highlights all the Grand Lake St. Marys Region wetlands/natural spaces that are open to the public. Information on each project, including location, walking trails, establishment and more is included on the site. Check it out today!
2026 will bring several new projects. Improvements will be made to the inlet structures at the Prairie Creek wetlands and an additional lift station will be added at the Beaver Creek wetlands to double the treatment capacity. Work on grant applications for future development will also be ongoing.
The Lake Restoration Commission (LRC) will continue to fund the monitoring of the treatment wetlands throughout the watershed via an agreement with Wright State University-Lake Campus. As the State of Ohio has pulled funding for the monitoring of the H2Ohio wetlands, the LRC will now also fund the monitoring of the Southwest Greenspace wetland, the Northshore Greenspace wetland and the Burntwood-Langenkamp Wetland Conservation Area. The LRC spent just over $26,000 this year on maintenance and repair of pumps, structures and vegetation at the existing treatment wetlands.
Courtesy Tom Grabow & DaN GILLIS
The dredging program removed 279,988 cubic yards of sediment from Grand Lake St. Marys in 2025. On average, approximately 120,000 cubic yards are deposited into the lake annually, so the dredging program outpaced that figure this year.
Total Grand Lake Cubic Yards: 279,988.28
Brutus Dredge: 134,726.66
Hoedag Dredge: 145,261.2
Windy Point south side of channel still ongoing. North side of channel complete and north side out at open water complete. Hit various spots around lake with washouts throughout the year.
Barge and excavator still out removing dead and leaning trees in channels. With the water level being down this is slowing operation down and changing the way we attack things. Last report they were over 500 trees and stumps.
Courtesy Matt Staugler & Jared Ebbing
The year 2025 represented a continuation of positive and successful development in the region, with hotel stays matching the record set in 2024. Continued investment in downtown Celina and along the lake is a sign of a healthy lake-influenced economy that we anticipate continuing into 2025.
In addition, the Visitors Center continues to amplify awareness about Grand Lake St. Marys, earning:
Courtesy Brad Fisher, Grand Lake Recreation Club & Lake Improvement Association
Together with multiple community partners, the LIA funded a playground for the West Bank, then partnered with the Grand Lake Recreation Club on a shelter house to be installed alongside the playground adjacent to the ADA dock. Installation planned for 2025.
The LIA received a grant from the Auglaize County Board of Developmental Disabilities to purchase an All Abilities Playground to be installed adjacent to the first shelter house on the East Bank. The LIA also helped fund the playground, which is expected to be installed in 2025.
The Grand Lake Recreation Club and LIA partnered to rebuild the north dock on Safety Island and add a floating dock. Unfortunately, the dock was destroyed shortly after by a falling tree. The groups plan to restore it again in 2026.
At the state park’s request, the LIA purchased a heavy duty grill for Sunset Beach.
The LIA purchased concrete cornhole boards for Sunset Beach.
The LIA conributed significant funds toward the purchase of a new algae monitor to be used by Wright-State University Lake Campus. The device will make it easy to measure multiple types of algae in the lake.
The LIA purchased lumber to rebuild picnic tables used in shelter houses and throughout Grand Lake St. Marys State Park.
The LIA and Grand Lake Recreation Club donated $9,000 for the mainenance of the bike path on the south side of Grand Lake.
The LIA awarded 3 scholarships to Wright State University-Lake Campus students pursuing degrees in water quality-related fields.
Distributed over 20,000 lake maps
Public meetings held monthly
Website, social media, email newsletter & Grand Lake app
Entertaining & informative presentations on Grand Lake oil history, snakes of Grand Lake, Grand Lake furbearers, Grand Lake trivia, and more
Courtesy Brad Fisher, Grand Lake Recreation Club & Lake Improvement Association
More than 400 children, teachers, drivers, state park representatives, and volunteers converged at the East Bank Fishing Pond for this year’s event for developmentally disabled children in the Grand Lake region.
The LIA’s annual winter dance continued to be one of our biggest annual fundraisers for Grand Lake improvement efforts. Be sure to get tickets to see My Yellow Rickshaw at the 2026 Winter Icebreaker!
Our biggest annual fundraiser was another roaring success with over 240 teams and 1,000+ participants. Thank you to all the volunteers who make this event a success!
The LIA also had booths to promote lake improvement efforts and support local lake-related events.
The Grand Lake Recreation Club held another successful Bicycle Poker Run in 2025.
The Grand Lake Recreation Club welcomed everyone to a fun day of music at Boater’s Beach for the July 4 festivities.
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