Wow Ken I'm really sorry to hear this. I've often wondered if this could happen to me as I'm close to a state highway, and if they wanted to widen it, if they choose to do so on my side the pond will have to go. It would be easier to do so on the opposite side which is a farm but who knows how these people think.
We're supposed to live in a free country. Sometimes I just don't know about that.
I hope it all works out for you, and could even be a blessing in the end if with this being a buyer's market you could find a dream property at a steal. Buy one of those closed trout farms with a pond already on it! Or a property that has an artesian well where you could have trout year around along with your other warmer water species. Flow water from the trout pond into another pond that is bigger and stays warmer which is what I used to do.
