Northern ponds especially those that have 3"+ snow cover should be aerated in winter. Need for aeration increases after complete snow cover has laid on the ice for 2-3+ weeks. The deeper the northern pond the less need for winter aeration. Deep water results in high volumes of water with lots of DO at ice formation. The more the percentage of the pond with deep water 15ft+ the less the need for aeration in winter.
Another factor is how much snow is removed by wind to create clear or snow free ice. Snow free areas of 20%+ results in less need to aerate. Sunlight that penetrates ice cover causes phytoplankton in the water column to produce DO 2 times deeper than the light penetrates into the water. Example: if water is clear (vis 5ft) and no snow is on the clear ice phytoplankton will produce dissolved oxygen in water up to 10-12ft deep.
In some northern ponds (7-12ft) with less snow or shorter periods (2-3wks) of snow cover, aeration is not usually necessary unless the pond contains lots of dead organic matter, thick mucky bottom sediments and/or old growth submerged vegetation which all consume significant amounts of DO during the winter ice cover period. Winter aeration becomes an important factor for fish survival in these ponds.
All the above factors determine how much aeration is needed and how often and how long one needs to operate winter aeration. My pond at 14 ft deep currently has 2" of ice with 1" of snow. I have not turned on winter aeration as of Jan 16. I will start aeration when 3"-4" of snow has accumulated for 2 weeks. I will aerate until I produce a large ice free area 20ft-50ft dia; then shut it down. Open water allow lots of sunlight to create DO in areas surrounding the open water. Then aerate each day until I recreate an ice free area 40-50ft dia. Cold winter water circulates very easily so any DO in the ice free area gets widely distributed to far areas of the pond. To date I have not been able to measure how far the aeration currents spread the cold water & DO beyond 150ft.
Last edited by Bill Cody; 01/16/16 12:28 PM.
