When you are being challenged legally, make sure you take the right approach. Don't do any work for the other side, and make the other side be explicit about what they are charging you with and WHY.
When you cited the clause that you "think" they are taking issue with, you were demonstrating that you're doing their job for them. The C&D Letter that you got cited the laws / ordinances that you are supposedly in conflict with, but I didn't see anything in what you posted that stated WHY you were in conflict. There's language in there about disturbing the soil and such, but I didn't see where it said "by performing X act, you are disturbing the soil".
Challenge them to cite the details of their issue with this and then you will understand what it is that you (and your attorney) have to argue. Removing vegetation will absolutely affect the grounds ability to absorb water. Make them spell out exactly what it is that you are doing that causes the issue (like removing vegetation).
If they can not, or will not, do that, have your attorney file a countersuit against them for making false claims or whatever else he can come up with. You need to compel their "evidence" so that you can refute it. Also look for conflicting laws / statutes that are in your favor. For example.. If they issued a C&D to you for cutting down very tall grass, but your town (like most) has an ordinance that REQUIRES that grass be kept cut, you have something very strong to argue back with.
Your representatives, senators, first selectment, etc are not going to be as well versed in this as you might expect. And, they are very unlikely to do anything to actually help you.
CALL THE FARM BUREAU and ask them to refer you to an attorney. If you are not a member of the farm bureau, consider joining. Your membership just might entitle you to either free or reduced fee counsel.
Above all else, stop seeking advice here. The more time you spend trying to understand how to fight this by reading advice on a forum, the deeper in the hole you will be when you realize you need an attorney.