PONDS
There are five ponds throughout the neighborhood, which provide drainage for storm runoff and recreation for residents. While plant life in a pond is a sign of a healthy ecosystem, without regular treatments, algae and rooted aquatic plants would grow unchecked and eventually produce some undesirable effects. Too much plant life in a pond can actually suffocate the fish in the ponds by consuming too much oxygen in the water. Additionally, rooted plants and algae building up in the shallow waters provides the perfect conditions for mosquitoes to breed in the shallow, stagnant water. Lastly, algae literally stinks, it gives off a rotten egg odor, and should enough algae accumulate in the pond, you'll be able to smell it regardless of whether your property is located on one of the ponds or not.
The HOA coordinates annual stocking of grass carp in all neighborhood ponds. Grass carp are a cost effective method to maintain a healthy balance of plant life in a pond. The goal of these treatment options is not to have zero plant life in the pond, only to keep it at manageable levels. There will always be some plant life growing on the bottom of the pond and there will always be some amount of surface algae that collects along the banks. To mitigate that, dredging is a useful tactic that residents can choose to undertake themselves should the situation call for it.
GRASS CARP
Grass carp are large herbivorous fish that primarily feed on aquatic plants that grow up from the floor of the pond, but they will also consume surface algae. How large are these fish? When fully grown, they're about 2-3 feet in length. You'll often see their fins flapping around the surface in the early hours of the day and at dusk. They eat about twice their body weight per day in vegetation. This stops plants from growing all the way to the surface of the pond, which in turn helps reduce the amount of algae. Algae grow near the surface, which is why you'll see it collect along the banks in the shallow areas. However, when plants grow from the floor of the pond to the surface, their leaves provide additional areas for algae to flourish. The carp have a 5-10 year lifespan, so each pond has had an initial amount stocked based on its size, and we then add a few carp to each pond every year so that we'll maintain a consistent population level.
One note, the grass carp are living organisms that go where they please. They won't travel the pond like a pool skimmer, methodically hitting every area evenly. As a result, there may be times where plants grow close or all the way to the surface before the carp get to them.
DREDGING SHALLOW AREAS
If the shallow areas along your property has a lot of plant life growing near the surface, the carp likely won't get be able to get in there and eat those plants. As a result, you may see a lot of algae building up along your bank. One tactic that has been helpful in that scenario is removing those plants using garden rakes. A metal garden rake is good for pulling the plants out from the sediment on the bottom. The plants are wet, so they'll be a little heavy to pull out of the water, but if you leave them to set on land for a day or so, the sun will dry them out and they'll be as easy as grass clippings to move. Depending on how far the shallow area extends, you may need wading boots to get out into the water.
CHEMICAL TREATMENTS
There are chemical herbicides available that can have dramatic effects on reducing plant life in a pond. However, these chemicals are very expensive and not something the HOA could budget for given our current dues and level of participation among residents. Additionally, these are EPA-regulated chemicals that can only be applied by licensed professionals. Permits are required, as well as consent from every property owner that touches the pond.
We used to have a light-filtering dye applied to the ponds that blocked certain bands of the UV spectrum that aquatic plants rely on for photosynthesis, which had the effect of slowing plant growth in late spring and early summer. Unfortunately, in 2020, these chemicals were moved into a different classification by New York State. As a result, the vendor we had relied on to apply this dye to the ponds could no longer perform this service for us.