Littering next to river while swimming?

First of all, I am only licensed to practice law in Ohio so my response is limited by that restriction. Second, this is really a criminal law issue, which is not one of my primary practice areas. That being said, my suggestion for you is to read the ticket or the criminal complaint that was filed against you very carefully to determine the particular littering statute that you are being accused of violating.  Whether the charge against you is valid will depend on the wording of the statute.  For example, the Ohio statute prohibiting littering is found at Ohio Revised Code 3767.32 and provides as follows. (A) No person, regardless of intent, shall deposit litter or cause litter to be deposited on any public property, on private property not owned by the person, or in or on waters of the state unless one of the following applies: (1) The person is directed to do so by a public official as part of a litter collection drive; (2) Except as provided in division (B) of this section, the person deposits the litter in a litter receptacle in a manner that prevents its being carried away by the elements; (3) The person is issued a permit or license covering the litter pursuant to Chapter 3734. or 6111. of the Revised Code. So, by a strict reading of this Ohio statute, the fact that you never intended to leave your cans in that location is not a valid defense because the intent is not determining factor.  By no placing the empty cans in a litter receptacle that would prevent such litter from being carried away by the elements, your actions (no matter how well intentioned) meet the definition of littering. In conclusion, the answer to your question will defend on how the North Carolina littering statute is worded.  I hope this helps.