Jamesville Beach's Algae Buoy Trial Wraps Up This Month. The Real Test Comes in July.

On Thursday, July 2, 2026, with heat index values forecast as high as 106 degrees, County Executive Ryan McMahon made Jamesville Beach Park and Oneida Shores free through Sunday, syracuse.com reported. Admission is normally $7 per vehicle.

On Sunday, July 5, the County's water quality log shows Jamesville Beach closed for algal blooms in the water. It reopened on Saturday, July 11.

Six weeks later, Onondaga County Parks put three ultrasonic buoys into the Jamesville Reservoir to fight those blooms. The trial is scheduled to run through mid-November, so it wraps up this month. Because it started after the July bloom window, it could not answer the question it was set up to ask. Next July will answer it.

July Is When the Reservoir Turns

Blue-green algae closures at Jamesville have come in July, year after year. The Onondaga County Health Department's notices and the County's own log show the pattern:

Some years the first closure is not the only one. In summer 2025, Spectrum News reported that Jamesville Beach closed on August 1, first for high E. coli and then for visible algae. By mid-August, WAER reported that it was the second bloom closure that month and the fourth of the summer.

The County's reopening rule makes each closure last longer than a single bad afternoon. Once a bloom clears, the water has to be tested and found free of toxins before the beach reopens. In 2026 that process took six days. In 2025 it took seven.

The Buoys Went In After the Window Closed

The County describes the project on its Jamesville Beach Park page. Three LG Sonic buoys, each 8 feet across, send low-frequency ultrasonic waves through the water. The waves break down the air pockets that blue-green algae use to float, which keeps the algae from rising to the surface to photosynthesize. Each buoy treats 50 surface acres, so together they cover 150 of the reservoir's roughly 160 acres. The stated goal is to reduce harmful algal blooms and "increase the number of operational, safe swimming days."

Here is how the 2026 calendar played out:

1. July 5: Algae bloom closes the beach.
2. July 11: Beach reopens after the bloom recedes and testing comes back acceptable.
3. August 14: The three buoys are deployed for a three-month proof-of-concept trial.
4. August 17: The beach closes when a sample reads 435 E. coli per 100 ml. The County's threshold is 235.
5. August 18: A retest comes back at 93, and the beach reopens with extended swimming through Sunday, August 23.
6. Mid-November: The trial reaches its scheduled end.

That leaves about ten days of overlap between the buoys and the 2026 swimming season, from August 14 through August 23. All of them fell after the July window that produced each closure in the table above. The one closure during the trial was caused by bacteria, and the County measures bacteria against a separate standard. The County notes that elevated bacteria can come from watershed land use, stormwater runoff or naturally occurring sand and soil bacteria. The buoys are built to work on cyanobacteria.

The fall months still produced something useful. Each buoy works as a floating water lab that continuously tracks dissolved oxygen, chlorophyll, phycocyanin (the pigment cyanobacteria carry), turbidity, temperature and pH, and LG Sonic engineers review the data as part of the project. Three months of readings give the County a baseline for the reservoir. What the trial could not deliver in 2026 was the thing its goal names, a July with more open swimming days than the year before.

At the August 20 meeting of the County's Fisheries Advisory Board, the minutes record that the study was expected to last until fall, "with further information to be provided." At a September 17 budget review, Parks Commissioner Brian Kelley listed the buoy test among the department's 2026 initiatives, with the aim to "reduce harmful blue-green algae and increase available swimming days."

The project also has a local connection. The County's page notes that LG Sonic's U.S. headquarters is in Skaneateles.

The Splash Pad Is the County's Plan for Closure Days

The County approved its backup for closure days months before the buoys arrived. At a March 24, 2026 Ways and Means committee meeting, Commissioner Kelley walked legislators through that year's parks bond. For Jamesville Beach, the minutes list three items: install a splash pad, relocate the volleyball courts, and "hire an engineer to do research on blue-green algae mitigation in the Jamesville Reservoir." The minutes summarize his reasoning in one line: "beach has to close often, hence the splash pad."

The full Legislature adopted the bond 17 to 0 on April 7, 2026. The County's 2027 to 2032 Capital Improvement Plan lists Bond Resolution 2026-053 at $3,460,000 in total, with these Jamesville Beach lines:

• Installation of a splash pad: $490,000
• Relocation of volleyball courts: $90,000
• Blue-green algae mitigation: $200,000

The County is paying for a fix to the water and for a place to cool off when the water is closed. Spending nearly two and a half times as much on the splash pad as on algae mitigation tells you which outcome the County is preparing for. A splash pad is useful only on days when swimming is not possible, and the County approved one the same spring it approved the algae research.

The Reservoir This Winter and the 2027 Calendar

From November through March, Jamesville Beach Park is closed. The off-leash dog area in the Special Event Field stays open, and admission is free outside the peak season. Dogs must be under visual and voice control there and leashed once they leave it. The County's rules extend that leash requirement to everything east of Butternut Creek outside the dog park. That covers the "J" Trail, which runs about 1.25 miles from the bridge, while the "B" fishing trail runs about half a mile from the Sandpiper Shelter south to the bridge.

The County has already posted the 2027 beach calendar:

Line that calendar up with the closure table. The earliest algae closure in the past four summers came on July 5, two weeks into the daily season. A 2027 version of the buoy test that wants to measure swimming days would need to be in the water before then, during the weeks that have produced every recorded first closure since 2023.

The season pass goes on sale online April 15. It costs $50 per vehicle for Onondaga County residents, $100 for non-residents and $21 for seniors 62 and older. The pass is valid at both Jamesville Beach and Oneida Shores. The beach's daily status is posted on the County's water quality testing page.

The park will also change shape beyond the water. For 2027, the Capital Improvement Plan lists a $365,000 Visitor Center reroof, a $225,000 Overlook Shelter deck replacement and a $180,000 pay gate. For 2028, it lists $980,000 to repave the parking lot and driveways, two pickleball courts at $270,000 and a $200,000 picnic area with tables and grills.

Nearby, Clark Reservation State Park is holding a free Winter Lantern Walk on Wednesday, December 9, from 6 to 7:30 p.m. The walk is for adults 18 and older, and registration goes through the Liverpool Public Library. Participants meet at the large pavilion, make a candle lantern and walk the wooded paths. The Friends of Clark Reservation also list a First Day Hike on January 1, 2027, from 11 a.m. to 2 p.m., and the event page currently shows registration as closed.

Whether the buoys work will be clearest the first week of July 2027, when the water warms and the County's log shows whether the beach stays open. For more on Jamesville, the Town of DeWitt and the neighboring communities, Robert Zaccaria keeps a Jamesville neighborhood guide and is glad to talk through what changes at the reservoir could mean for the homes around it. Let's Connect.