Pond Boss Forums POND CONSTRUCTION Selecting a site Northern Ponds Long Winters Nap

I've been "out" for a couple days & I will work on your questions.
The pond is not napping during winter. Lots to things happening under the icecover. The same things are happening during winter as during open water seasons but they are just happening slower due to colder water. Things are living and dying under the ice. Water chemistries are changing daily. Sediment activities are still occuring just slowrer. About the only things napping are the frogs and turtles who hibernate in the mud. The pond muds and bottom areas, depending on depth into the sediment, are relatively warm 42F to 48F compared to the ice cap and water just below the ice. The water just above the bottom ranges from 40F to 44F depending on depth above the bottom. Inbetween water is 39F

1. Young or new ponds typically do not need aeration during the first several winters. Need for Winter aeration of northern ponds is caused mostly by high organic loads or deposits on the sediments and extended periods of deep snow cover.

A. The abundant organic deposits on the bottom cause high oxygen demands year-round. However the oxygen consumed by the decomposing organic materials in sediments is greater (due to temeperature) in the summer than during the winter. You will not need aeration during winter until the sediment deposits get thicker due to several years of accumuilation and how much is deposited each year. Some use aeration to keep some water open and allow light penetration for oxygenation. Winter aeration during ice cover supercools the water to temps below 39F which can be stressful for fish.

B. Snow cover on a pond blankets out the sunlight and all plants esp micro phytoplankton start dying. This death cause lots of oxygen cunsumption due to bacterial decay of the additional dead organics. No light penetration results in no oxygen production during day light periods, so the pond organisms have to survive on the oxygen stored in the water column. When stored oxygen drops below 3 ppm fish start suffocating. Obviously the deeper the pond the more oxygen that is stored in the overlying water volume.

Advanced Info. Ability of oxygen storage in pondwater during winter is not just a matter of water volume; large acreage ponds doing better vs smaller ponds during winter. In the north it is important to have greater depth over the sediments versus large areas of water over shallower depths. This gets into ratios of sediment surface areas to overlying water volume (depths). The higher the volume to surface ratio the longer the stored oxygen will last.

Keeping abt 20% to 40% of the snow cover off ice is usually adequate to provide enough oxygen production during ice cover. Light penetrates ice much better than snow. Try not to let snow cover lay on the entire pond longer than 2-3 weeks before some of it is removed.

2. Not much preperation is needed before winter unless you have lots of leaves that drop or blow into the pond. Try to remove as many leaves from the surface before they sink as possible. This decaying leaf matter is a big consumer of oxygen. Also if you catch fish in fall or early winter be very careful how you handle them. Handle them as little as possible. Maybe even unhook them under water!!. DO NOT drag them on the ground or mishandle them. This wipes lots of slime off the fish. Slime layer protects the fish from cold water fungus and parasites/disease. The fish do not replace slime quickly during cold water and fish can get "sick" often die much later during winter or early spring.

3. Snow removel methods are your own best common sense. I shovel lots of my snow off. It gets me out of the house on late afternoon weekends, gives me winter excerscise, and helps the pond. If you have kids get them to help so they can ice skate/play on the ice. I remove the snow in strips, each 4 to 7 ft wide the entire length of the pond. If you want to skate you may need to remove wide areas. Some use snow blowers or four weelers with blades to quickly push/blow snow off the ice. Verify ice thicknesss before using heavy machinery on the ice. Ice under thick snow 8" to 12" freezes slower and is usually thinner that ice with no or little snow cover. Snow acts as insulation for layers underneath.

Postscript. The windmill aerators will only mix about 1/4 to 3/4acre of surface water regardles of how big of a pond or lake they are put in. They have limits and only create so much energy to disapate into the surrounding water. Obviously the more energy generated the greater the output and water volume that can be mixed; weak vs strong forces.