Pond Boss Forums AERATION Systems questions Aerator Iced and Snowed Over

1. 5" of snow cover on clear ice allows only 1-3% of the light to enter the water under the ice. Plant DO production needs to have 10%-12% of light on the ice cover to produce dissolved oxygen (DO).

2. Your 3 yr old Pond is considered new in terms of the life of the pond. This means the amount of dead organic accumulation on the bottom is low and with bottom aeration a lot of the organic sludge has been decomposed due to well oxygenated bottom water circulation from the bottom aeration. The lack of bottom muck means the oxygen will last a lot longer during the ice and snow covered conditions compared to a pond that is 12 to 20 years old. As the pond ages to 10+ years be more concerned about winterkill. My estimate the DO on the bottom of the deep basin of your current newish 3 yr old pond should last at least 4-5 weeks with complete snow cover before you should be concerned about a fish kill. If lots of tree leaves entered the pond in fall then DO could become in short supply by 3 weeks of snow cover in your new pond. Old dead organic rich ponds are the one most prone to winter kill. Because ice freeze up was late this year around Jan 1 the harsh winter will not last as long as prior years so IMO chances of winter kill is low for states in the Iowa latitude.

3. 25% of the pond at 12ft deep means more water volume to hold more DO that in a newish pond should add another 2 weeks of good DO for a total of 5-6 maybe 8 weeks before water column DO is lost. Remember every living thing during winter water is 39F water from 2ft deep to the bottom. This means all bacteria to the biggest critters are basically dormant and they use very little DO. Ponds freezing up have 11-13 ppm DO which means it takes lots of weeks of respiration from bacteria to fish to use up all the DO in 8-12 ft of water column

4. If you are overly concerned and with the aerator turn it off for several days of ice forming temps, then IMO you should auger a hole about 3-7 ft from shore. Then restart the aerator to allow the air to escape and the dissolved gasses if present in the water to escape. If you do not trust walking on the ice, auger holes 1 -2 ft apart to very the ice thickness as you move away from shore. 4" of ice is plenty of thickness to hold you up. I walk and fish on 3" of ice. A guy this week ran a snowmobile on 6" of ice no problem.

5. My way of checking the amount of DO during ice and snow cover is to go ice fishing in the deepest part of the pond. Put the baited lure 6"-12" from the bottom. If you can catch a fish at 11-12 ft deep there is good DO on the bottom zone of a 12 ft deep pond. When the DO is lost during ice - snow cover DO is first lost on the bottom and then very gradually and slowly DO loss works its way up toward the ice bottom layer. This takes numerous weeks during the 39F water temps not days as DO can be lose during warm water of summer. 12feet is a long depth of water column to loose DO in winter.

6. A January or February thaw or a rain should usually occur in a typical Iowa winter. This often melts most of the snow when snow is less than 10"-14" thick. Then With melted snow down to some bare ice, light again enters the ice for DO production. then we just wait for all snow and ice to melt.