Fenway restores himself.
A bog pond is simply a small self-sustaining body of water such as this. I dug an irregular hole 2-3 feet deep in the vegetable garden, about 2-3 feet deep at one end, and maybe 8-12″ at the other. I carved a shelf where the dog’s nose is (note the rock sitting on it) and another at the far end. Into this I put a black, flexible rubber liner available at Lowe’s or any aquatic supply store (Agway sometimes). Overlap the edges by at least a foot or two. This I covered with flattish rocks, fitted together, to hold it in place. Or, I overlapped the plastic 2-3 times and drove in a 10-inch spike. That way soil could remain exposed for shore plantings. This all becomes clear as you go along. Use a level and flat board to be sure all pond edges are at the same height (give or take).
Slowly fill the pond liner with water, tucking dirt under any low spots. Then add aquatic plants (which are cheap, until you get to fancy were lilies), and some fish. I put in a few goldfish, small Koi, and some polliwogs. These will eat mosquito larvae.
The only problem after that is algae that forms on hot, summer days. I fix this by squirting a spray of hose water.
And that’s about it. I like to keep things simple.