>>343433I know that story all too well. A lot of the ponds around here can no longer be fished for the same reason. When my father used to fish a lot more, and when I was younger, it used to be nothing to knock on somebody's door and go "Hey, do you mind if I fish your pond?" and let'em know you intend to throw everything back or that you can give'em what you catch. Sometimes you might offer them a fiver or ten-spot but most of the time they didn't care and just said to go ahead. These days you're lucky if somebody answers the door and if they do they'll probably look at you like you've got three heads. Try to strike up some kind of deal. If other people have left trash around offer to clean up the place in exchange for permission to fish it. If it's an older person or somebody who doesn't seem apt to do their own yard work maybe try a "mow your lawn if I can catch some fish."
Best advice I can give is: It won't hurt to ask / worst they can do is say "no." That or hop on Google Maps and look for new waters.