Enclosure Advice- box turtle and sliders pond

[bat-turtle]

Digging out a pond/waterfall in my back yard and would like to make it good for both box turtle and sliders year round.
What considerations do I need to have in order to ensure winter survival, etc. (Tennessee) I imagine a certain depth is important?
Would koi be ok in the pond? Educate me!

 

[DoubleD1996!]

Digging out a pond/waterfall in my back yard and would like to make it good for both box turtle and sliders year round.
What considerations do I need to have in order to ensure winter survival, etc. (Tennessee) I imagine a certain depth is important?
Would koi be ok in the pond? Educate me!

3 1/2 to 4ft deep would be excellent. The length should be decent as well.

Make sure the pond has a pump and filtration. Box Turtles are surprisingly aquatic and will take advantage of the water, even brumating inside of it.

You want it to be enclosed of course, with plenty of foliage, logs etc for the box turtles to hide under. You could even use pallets.

Those logs and such also give insects a place to hide, which act as waste cleaners and food for your turtles.

Koi can survive with turtles, but I don't recommend it. One day the turtles won't bother them, the next they're eating them. Fast moving fish like brim and bass tend to do well.