Good luck on your trout experiment!

I like that your pond is 28' deep at full pool. You will have a pool of cool of water below the thermocline to work with.

I don't like that your deep pond went dry during the drought. I suspect you probably have zero groundwater entering the pond to cool the water during summer. Therefore, your pondwater temperature will rise as the air (and soil) warms throughout the summer.

To keep your trout alive, you will have to perform a very delicate balancing act.

The cool water below the thermocline will be ABLE to hold more dissolved oxygen, but it will be oxygen depleted to some extent due to the stratification of the pond.

I have linked a dissolved oxygen chart to show the temperature relationship.

[Linked Image from cdn.calisphere.org]

You will need a temperature probe and oxygen probe to establish the depth profiles of temp and DO.

Consider two identical ponds with the same temperature in June. The first pond is aerated from the deepest point to mix the cool deep waters with the warmer surface waters. The second pond is allowed to remain in its naturally stratified state.

The average temperature of the stratified pond will be lower in the period from July through August compared to the aerated pond. A pond that has the hottest water at the surface will gain less heat during a summer day and lose more heat during the night compared to a fully-mixed pond

Therefore, I don't believe aerating from the deepest point is your best solution. The pond with the cooler average temperature will be able to hold more dissolved oxygen for the trout, but as you add oxygen via aeration, then you will also be warming the pond.

You will have to use your cool bottom water to slightly cool your column of well-oxygenated water above. You may have to run some shallow aeration 24/7, and then turn on some deeper aeration in the late night/early morning during the hottest parts of the summer. Perhaps you can lower that aeration a foot/week from 14' to 22' during the hottest 8 weeks of the year for your water temps.

There are several threads on the forum where people have had to work very carefully to balance their DO and temperature via aeration - usually due to pushing right up to the upper limits of how many fish could be supported in a pond of a given size. (You might try searching for some of those old threads. I believe most of them are in the Aeration sub-forum.)

I would keep lots of records and experiment with a small number of trout like you proposed. I really like your idea to run the experiment with no predators. That is the only way to determine if you lost your trout due to insufficient DO.

If you posted your weekly data from this year in the Aeration section, then I bet you could get some valuable input from some of the experts.

If you can get trout to survive in Year 1, then you can go big on your trout in subsequent years and also add LMB as you may desire!