Duck Pond, a few minutes away in Croton, has had an aeration system (underwater bubblers driven by a compressor on shore) for several years. That system was the model for the motorized aeration proposed for Kaplan's Pond in 2025.
But as our neighbor Jeff, who took the photos above, points out, these are two completely different ecosystems and need to be viewed that way. Duck Pond sits at a lower elevation in a more densely populated neighborhood, and as Jeff notes, an elevation map shows it collects runoff from the streets above: Ridge Road, Elmore, Darby, Radnor, and the middle school. That runoff carries road salt and pet waste with it.
So Duck Pond is not a stand-in for Kaplan's Pond. But because it was the example offered, it is worth looking at how it has done.
July and August brought more than 15 inches of rain. On August 23, our neighbor Tom photographed both ponds.
Kaplan's Pond was clear of surface growth. With so much water moving through, the pond was flushed out naturally.
Duck Pond, with its bubblers, had a carpet of surface growth. It received the same rain, but there appears to be little water flowing through it, and the aerators alone were not enough to keep the surface clear.
Three weeks later, in mid-September, Jeff's photos at the top of this page show the same picture: Kaplan's Pond still clear, Duck Pond still covered.
A note in fairness to the Village: the Duck Pond aerators broke down earlier this summer, which may have contributed to the growth seen here.
At the July 23, 2025 Village work session, the aeration vendor was candid about Duck Pond:
"It is currently harder to maintain Duck Pond in as good a condition with just the aeration that we're doing in Duck Pond than it was three, four or five years ago."
The vendor also said there was no guarantee that aeration alone would solve algae or weed growth at Kaplan's Pond. At the same meeting, the Village's DPW foreman described a compressor failure at Duck Pond: within about two weeks, the algae began building up again.
In other words, the system needs to run continuously to hold things back, and even then it can be outmatched.
Tom also visited the beaver dam at the Arboretum. Water was spilling over the dam after the rain, but the still swamp behind it was thick with the same surface growth seen earlier at Kaplan's Pond.
It appears to be duckweed, a native floating plant that thrives in still, nutrient-rich water. Nutrient runoff from upstream (lawn and turf fertilizer, for example) is a likely contributor. Most of it was swept out of Kaplan's Pond by this summer's rain, while the beaver dam has created pond-like conditions closer to the source.
These photos don't settle which pond is "healthier." Ponds change with the weather, the season, and what flows into them. But a few things stand out:
- Water flow matters. Kaplan's Pond cleared itself this summer with no intervention at all.
- Aeration alone did not keep Duck Pond clear, consistent with what the vendor told the Village in 2025.
- Surface growth tracks still water and nutrients, as the Arboretum swamp shows. Addressing what flows in may matter more than adding equipment.
That is why we believe the right next step is to understand the pond first, with a credible baseline measured against goals the community sets, before choosing any treatment.
August 2026 photos courtesy of Tom; September 2026 photos courtesy of Jeff.