I am pretty straight laced, very conservative, and even attend church regularly, but I have been dragged to court a few times, and Destruction of Wetlands was one such reason. I would be VERY leery about doing anything regarding "altering the
course of a stream" I can tell you that personally.
And that was many years ago.
This past winter it got even worse. Because of the Supreme Court Ruling that now allows the Army Corp of Engineers to get involved with ANY waterway and not just navigable waters as before, you can not only be fined by the State Dept of Environmental Protection, The EPA...you can add an additional fine by the Army Corp of Engineers. None of this makes any sense either. While it is 100% legal to clear cut
wood in an area to be determined to be a wetland, bulldoze stumps to make logging roads anywhere through it, or drive equipment through the mud; if used for agriculture purposes (and this includes permiculture) we are subject to fines under the 1985 Farm Bill that makes it illegal to cultivate crops in wetland. Its unofficially called the Swampbuster Act.
It is unbelievably filled with bureaucracy and subject to the determination of just a few people in power.
I ran into this issue again just two weeks ago when an area on my farm was determined to be a forest wetland (no stream). The guy making the determination made some assessments that were not correct, and in short its not due to the soil or vegetation that the area is wet, but rather because ledgerock sits just under the surface.
Water always sits atop ledge rock. He said ledgerock was down 15 feet or more, but in actuality it was about 3 inches down I found out when I dozed a stump out of the ground. (Allowed because it was in the construction of a logging road). I could file an appeal, but if it comes back as wetland again, I not only have to pay for the filing fee, I have to pay for the Federal Government's legal fees.
So it is kind of like this; one or two guys in the state can make the determination if an area is wetland or not. You can appeal the decision, BUT your going to pay royally if you are determined to be wrong again. And the 1992 Farm Act prevents 3rd party's from making determinations so guess who will make that determination again? Then if anything is disturbed (if you grow food as logging is acceptable), you can be fined by 3 environmental agencies. As I said it makes no sense.
You did not go into great detail with what you want to do, but it is very possible you would be in violation of the swampbuster act.