Pond Boss Forums AERATION Systems questions Is aeration always necessary?

WiPondGuy – 15 acres of water is a lot of water and very expensive to try and aerate and create turnovers.

IMO before you spend money on aerating a 15 ac pond/lake, here is what I think you should do before Sept 15 and IT is BEST done in August. You want to do this before the cool weather changes the 'Normal" mid-summer temperature - oxygen features of your 15 ac pond. If you don't get it done this year then schedule it for next year July-August before you decide to aerate this 15 ac of water.
Do or have it done as a temperature - dissolved oxygen profile survey in various parts of the pond. Also Create a depth contour map of the pond with the temperature and DO measurements every 1-2 ft deep. These data will tell you where the thermocline is (depth) and what areas in the pond usually in mid-summer have the least amount of dissolved oxygen (DO) and MAY need to be aerated.

AS the pond and all ponds age and weather conditions change these data will change sometimes dramatically, usually toward poorer conditions in a more eutrophic older pond during mid- summer is when summer fish kills are more frequent. Extended snow cover in longer WI winters also makes winter kills more likely.

You say - "The deepest part of the pond is 13' deep and the average depth seems to be 6’-7'." For a large pond, One really needs to know what percentage of the pond is not being naturally circulated by wind action and where those areas or sections are located for an educated decision to aerate or not aerate. This is especially true for large ponds 10+acres and relatively shallow as 10ft to 15+ft deep.

If I don't miss my guess from your brief pond description, and IF the pond gets periodic good wind action across 15 acres and there are occasional 6" high waves or almost white caps then all areas of the pond that are 6ft to maybe 12 ft deep should have decent natural water mixing. DO testing will tell you this natural mixing depth. However a pond in a wooded area with little or no direct wind action then likely poor natural vertical water circulation occurs. Wind action on the pond determines the depth that wind is able to mix the warm surface layer into the cooler deeper depths. Water temperatures also affect this mixing depth. Water clarity affects natural depth of DO production.

The volume of pond water or percentage of total pond water with DO near 0 will determine the chance of fish kill. The more deep anaerobic water in July-August that is present that could get mixed into the good DO water above will really determine if bottom aeration is needed in this pond. It is this anaerobic water that causes fish kills. IMO if the pond has less than 10% to maybe 20% of the water as anaerobic conditions then IMO I would not aerate this pond. Or as an alternative I would just mix only the deepest zone depth/s to keep that anaerobic water pushed to the surface where it gets degassed and oxygenated in the epilimnion layer.