Lake Peekskill May 2026 Report
Lake Peekskill
On May 18, 2026, EverBlue Lakes conducted water quality sampling and analysis at Lake Peekskill at the following locations: Site S1, Site S2, and Site S4. Our program captured data on the following parameters with the following results:
• Total Phosphorus
• Ortho Phosphate
• Nitrates, Nitrites, and Total Nitrogen
• Silica
• Algal species analysis
Acceptable Nutrient Levels for a Lake:
Nitrite: < 1 mg/L
Nitrate: < 0.6 mg/L
Total P: < 30 ug/L in order to prevent nuisance vegetative growth.
Total N: < 0.75 mg/L
Discussion
At Lake Peekskill, the ultrasonic sonars were installed during the week of April 29th. Sampling had occurred then with the nutrient levels remaining high. Approximately 3 weeks after the installation, there was reduction seen similar to last year. Although, the average total phosphorus remains elevated, it has shown a reduction in the middle depth by 10 ug/L and 18 ug/L at the bottom water column. In addition to the reduction of the total phosphorus levels, the total nitrogen was also reduced by half, and on average is no longer elevated. There are some spikes in the total nitrogen levels at the surface in Sites S1 and S2 and the bottom water column at S4. Although there was a reduction in the nutrient levels, algal blooms and nuisance vegetation can still develop based on the elevated phosphorus levels.
During the May sampling period, there was a switch in dominant species from blue-green algae to green algae. Looking at the historical data, this seems to be the case, as the green algae has been dominant in May 2024 and June 2025. Data has not been collected in April prior to this year, but the switch between the dominant species has been significant and we believe the ultrasonic units have helped contribute to this extreme change.
Here is an additional look at the data that may be useful to communicate to residents.
The introduction of Ultrasonic Algae Control Technology to Lake Peekskill has correlated to significant positive changes in water quality data. Below are annotated graphs that show this change in relation to the timing of the Ultrasonic Implementation last August and this Spring.
While the data looks excellent, there are still many variables that could be impacting results other than the Ultrasonics – so we still have a long way to go and the real test will come as the weather gets warmer.
The nutrient levels in the lake while lower, are still of concern. So continuing to make progress on septic monitoring and watershed improvements is key to making the lake as resistant as possible to heavy blooms this season.
