My 1 ac. pond, formerly a small soup bowl shaped "frog pond" could not be dug out since it was mostly sand and gravel and chances were very good it would never "hold water"(unless it was lined w/clay--cost prohibitive!) I've wanted a pond since a young kid, sooo 30 yrs ago, we hauled in dirt(mostly bank-run) and raised the sides. I "rocked" nearby ag fields to put around the edges to help hold the banks til well established. We were only able to get a max depth of 6-7 feet in the middle. Over the years, we've put everything from gills to walleye in there for fishing diversity(NOT a good "textbook" stocking recommendation!) Since I aererate 24/7/365, everything survived(to my knowledge)-even a few nice cats and even some "wipers" from the Ohio river. Even with substantial cover around shore, I'm sure the walleye didn't reproduce since no young ones have been caught or observed. A larger pond with enough "wind/wave action" into shore Can allow reproduction however. The wave action causes enough "current/movement" to keep eggs from silting in which is why don't make it. Most of the inland lakes with walleye get plenty of wind and some do get "limited amounts" of reproduction. WB is one good example.