New member here trying to collect as much information as I can. I am planning on building a largemouth bass pond that will be around .75 acres. I am in the Southern Kentucky on a very hilly farm. I am going to dam up the bottom end of a small valley with a small spring feeding the pond at the upper end. The hillsides are very steep so the depth at the dam will probably be at least 20 feet even before doing any digging. I have seen where too much depth can mean low oxygen levels and be a dead spot in the pond. Just looking for some insight on this issue. Thanks for the help!

Will, welcome to Pond Boss. The answer to your question is yes. But, it exists in all ponds and is called a thermocline. Fish can go there but not stay very long. It is essentially storage that becomes usable when evaporation occurs and sunlight penetrates previously dark areas. Wind action and sunlight oxygenate the previously unusable areas.

So would I be better off trying to shallow the pond out? I could go further down the valley to build the dam which would be more work but make the pond shallower. I guess my question is whether to deal with the depth or the vegetation that comes with a shallower pond?

I’ve never known of too much water being a problem. If you ever get a Texas type drought, you will be glad to have it.

Better to have as much depth as the site allows, and steep 3:1 sides, down to a flatter bottom, to ensure against dropping too low in drought.

Not sure if it's feasible for your location but adding aeration would prevent stratification and allow your fish to utilize the deep water. Aerobic digestion of the bottom silt would also improve, slowing eutrophication.

Thanks for the input. I had his been confused after reading some info on depth. Steep is definitely not gonna be a problem as I am goin to have to use some dirt out of the banks to supply the dirt for the dam.

Are you going to be able to or plan to aerate it?

Honestly I am completely ignorant on what is involved in aeration of a pond. It’s quite a distance from any electrical source so I doubt that would be in the budget.

another way to look at it...all ponds collect silt, sediment, muck, etc. Starting deeper gives you more room to absorb excess material and still have adequate water depth

Welcome to Pond Boss Williek!

Since electrical source is far you can use alternative ways to produce electricity if needed.

My pond is not 20’, closer to 15+. I’ve not added aeration due to long distances from electric, and high cost of a good solar system. Our little BOW is only 4 yrs old, but it’s producing great fishing. Lots of fun swimming time, and is a pleasure to just sit by it.
I’m sure I’m gaining sediment in the bottom, as it’s ringed by tall timber. I may be paying a price later for not aerating, but only time will tell.
I also have on again, off again drought conditions, and a small leak, so when it’s down 4’ I think I’ve still got enough water for healthy fish.
I did go with steep banks to keep water plant production low, but then you almost have to build a dock in order to get out of the water.
Jeff