First off: I’m born and raised in FL I know the difference. These ARE water moccasins not just harmless watersnakes. We killed a very large one (for these snakes) yesterday. They are eating my goldfish and wild frogs faster than I or nature can replace them here in South Alabama. Not to mention I have outdoor cats that drink from the ponds edge and curious kids who like to watch the wonder of tadpoles close up and personal. At first, the pond was deep (2 feet) and steep sided….that didn’t work, it just let them dive where we couldn’t see them OR the fish we bought. Then we dug it out and expanded the pond sides making it more space with gradually sloping sides but less than a foot deep so that we could clearly see the sandy bottom and the fish we bought…..Still even though we can see them, they’re unwelcomed guests and now probably more of an issue because we now know there are more of them than we originally thought. When we kill one, another large one has replaced it within a week! Now, there are babies in the water and those are even harder to kill because they’re so small and quick. I need a pond solution and fast!
Here’s my thoughts: We have already spent nearly $1000 over the last two years trying to build a lovely water feature. I would hate to waste a brand new liner, brand new pump, not to mention all the rocks, plants and fish. But…..If I don’t find a safe solutions, my husband is threatening to fill it in. So, I need "snake proof" pond plans…if there is such a thing.
-IF I were to build a square box with sides say 2 or even 3 feet off the ground. Lay my liner inside this form and have a sort of large container garden; would this solve my problem with the moccasins?
-Are there any pond design ideas that will bar snakes from entering?
Please let me know….we love our pond, but Daddy’s more concerned with safety as all good husbands are.

Sounds like you have a source of good snake habitat close by. Yes a box with sides of smooth sheet metal will stop snakes. They cannot climb it. 24 inches would be the min although 30 inches would be better. You can use any type of metal roofing. It all looks surprisingly good in a vertical position as you would be using it. You can buy it in many colors.
Might consider a electric wire around a edge about one inch off the surface..
Also a teenager with a powerful pellet gun would love the job.. I know from experience you can kill all of them if you are persistent.