Watching summer ponds mist away into cool fall air is a cue to think about prepping for the coming winter. Here are some bases to cover as winter approaches.
If your pond catches falling leaves you'll be getting a nutrient load from the foliage. That organic matter can be food for future blooms of algae, as well as various pond weeds. Not good.
A lot of pond owners rake out fall leaves to reduce next year's algae and weed potential. With a garden rake you can clean up a narrow margin of leaves near the shore, but an even better tool is a pond rake made especially for water. They have a longer handle than a garden rake, with a rope that enables you to toss the rake farther offshore and haul in sunken leaves and debris. Pond rakes often have an attachable float giving you the option to pull in floating leaves or leaves and debris that float up during pond bed raking.
Of course, leaves land off wooded shore areas, but they can get blown around before sinking, so the entire pond bottom will often accumulate leaves. Some areas will be impossible to clean up short of dredging, but there are some locations it's effective to monitor for leaf buildup and raking.
Spillways and outflow pipes pull in leaves and make a good target for raking. A standpipe discharge will often suck leaves right out of the pond, but just as often leaves will gather near the outflow pipe and then sink and accumulate around the pipe. It can be a good place to police up after foliage drop.
Same for a native spillway, pond talk for an earthen discharge stream. Although fallen leaves will often flow out the spillway, they can get stranded at the mouth of the outlet, building up a leaf layer or sometimes plugging up the overflow. It's smart maintenance to rake them up.
In general, leaves raked out of the pond are best raked up and disposed of so they aren't left around to wash back or blow into the water.
And while you're on leaf duty, make sure your discharge systems (streams, pipes) are free of leaves and vegetation that could plug up overflows.
(See links at end of article for rake suppliers.)
Modular docks and rafts are often pulled out of the water in the fall. Especially in the north, ice can lock docks into places you might not want them, limiting skating areas. Getting docks and rafts out of northern waters also prevents ice damage to the structures. Putting boats away is part of winter prep, too.
If you're running an aeration system, opinions differ on cold weather operation.
Some folks turn aeration off for the winter months. In cold water, algae growth slows significantly, and if aeration is being used to control algae, it may not be needed in winter. Turning it off also saves on the electric bill. But if fish are stocked, and depending on species and amount, aeration may be good for fish health. Pond oxygen production drops way back in cold winter water, especially cut off from sunlight by ice and snow, so aeration is kept running for the fish.
Aerating in winter can endanger animals looking for water that's locked under ice. Aeration often prevents ice formation near diffusers or splashers. An animal attracted to open water may step out on the ice and break through and drown. To prevent this, some pond owners turn off the aeration system. Or move the aerator closer to shore where pond depth is less dangerous.
Keep in mind that some biological growth does occur in cold dark water, so if your ambition is to really reduce algae and plankton growth, by all means continue the aeration.
Which brings up the topic of using bacteria to improve decomposition of the organic matter that can nourish algae and weeds. Bacteria blends (often bacillus plus powdered barley) can be an effective water quality improver. Periodic dosing of the pond with bacteria from spring to fall is a common routine. But as pond water gets cold, bacteria activity slows down, and many folks stop use. Of course some biological growth does continue all winter, so bacteria may continue to be used. And some bacteria blends have been created to work in cold water. If you use bacteria for water quality improvement or consider it, check with supply sources for recommended winter use. (See links.)
Finally, If you've got tree work or tree removal planned, consider how much easier it could go in winter. Dropping branches and trees on thick enough ice makes a good platform for cutting lumber and firewood, and moving to woodshed, etc.
Pond Rakes and Weed Cutters from both suppliers:
Bacteria from a Vermont trout hatchery:
Aeration and other water improvements:
Topics vary from month to month and provide great information when researching where you want to build a pond, or how to keep it clean. Other areas of interest are pond use for more than swimming, and how to keep fish happy in your pond.