Neighbor problem
I'm an old fart and have seen situations many times before.. So, in the interest of acting like I "know it all" I would respectfully suggest.
1. Pick up trash, don't kick it in the road. Do you think the highly paid county folks are going to come by nightly and clean it up? Nope... All that will happen to it is a vehicle or mower will run over it, change it from 2 or 3 pieces of trash into 7 or 8. I too live in the country (on 5 acres) with 500' or so feet of paved road frontage. I mosey out and clean other folks trash out of the ditches in front of our property because no one else is going to do it, and it makes MY place look nicer.
2. Is the water draining to your yard contaminated, or does it just water you grass? Either way, since you mentioned you live "downhill" from the nut case you might just as well learn to live with it. It's WATER.....
3. I think you were wise in contacting the local law enforcement department. Now you have the situation on record.. Everytime another situation with the guy comes up, call 'em again. Keep a very nice paper trail. On the very rare chance you wind up having a physical confrontation with him you will start out being the good guy.. You WANT the leo's to think of you as the good guy.. Not the guy who starts the problems.
4. If there's anyway possible, consider a fence... Fences make GREAT neighbors..
5. At every opportunity IGNORE the fool. Don't seek trouble, just mind your own business and again, be the party the cops think of as the offended party, not the one starting trouble.
6. If on the slight possibility you ever shoot this guy you will be in for a whole lot of explaining as to your intentions for carrying the j-frame anyway. I'm not saying you are wrong in doing so, you just need to know that in my state (Georgia) you can't just shoot someone because he comes over and questions your manhood, or whatever. You must first retreat, and only in fear for your life, or the life of your loved ones, or innocent persons will you POSSIBLY get by shooting someone. I know retreating from a dangerous confrontation isn't seen as "manly", but in doing so you might save yourself from getting into a lot of trouble, having to spend a whole lot of money for a lawyer when you are sued by the deceased's heirs, and maybe having to mortgage or sell your acreage to pay for same.
The American judical system just isn't geared to come up with a fair and logical verdict, no matter how much we like to think it is. Or, you just might wind up being GUILTY, even tho' logically you might have been in the right. Or, in the right, as YOU saw the situation. You just can't count on getting a jury of intelligent, educated people. You might get the cretins like on O.J.'s jury, only with a reverse verdict.. To be followed by a civil suit to finish taking whatever you own.
So, pickup the trash in the road. Save for a fence. Be thankful for the free lawn watering. Ignore the fool like he isn't in the universe. Keep the j-frame handy, where you might find it when in "retreat" mode, but in fear of your life, but don't carry it up and down the yard hoping for a confrontation. Nobody wins if that happens.
Now, I'll go take my fiber, Zoloft, and take a nap.. I'm a senior citizen, semi-senile (my wife says "fully") and I'm not trying to start a flame war, or offend you. I just think caution is always the better part of valor, and worrying about this guy is taking up too much of your time.. Let it go.
Best Wishes.
JP