Originally Posted By: Quarter Acre
Well, a month has gone by and not much change.

Last night's water temps showed 40 to 42 (degrees F) from top to bottom. I keep thinking that it should be warmer towards the bottom. I do not expect to see stratification with the aerators on, but they have been off for over a month. Where's the stratification? I only measure temps down to the bottom at the end of the dock...7 foot deep, but the pond is 10 foot deep out in the middle. I guess I need to tie a longer cord to my thermometer and give it a good throw out in to the pond...my stratification plane may be below 7 foot.

We did get a thin layer of ice over the pond a week or so ago that lasted a few days. Pretty early for ice on the pond, but it's gone now.





Hi QA,

There are many reasons why it might not stratify yet. But here's one -- the water isn't cold enough.



The relationship of water density to temperature is parabolic. Meaning, the density of water increases as it cools--for a while. Then it goes down again. (see chart)

In the fall and early winter, the water cools at the surface and sinks. This water movement is often called pond turnover and keeps happening until the magic temperature of 39F is reached top-to-bottom. 39F is the temperature at which water is maximally dense.

Then it stops. When the water at the surface cools below 39F, it becomes less dense and won't sink. It will 'float' on top. The 39F water at the bottom is dense, and it will stay there. This is the winter stratification pattern.

Note that it's opposite of the summer stratification pattern, which is in a temperature range where the cooler water is more dense!


Last edited by Bocomo; 12/12/18 04:15 PM.