Jeff, water rights are as clear as mud but we deal with this on a regular basis in our duck hunting adventures. Basically, on a man made pond, trespassing and usage follows the original property lines. Just because a pond is built that covers multiple peoples property does not give anyone the right to cross the original lines. My brother owns the majority of a soil conservation lake and we have been around this every direction possible. With that said, the vast majority of LEOs in the state are LOST when it comes to laws concerning surface water.
To further complicate it, the person that controls the dam or flood structure can be held liable for any actions they take that affect the surface water on the other owners property.
[This message has been edited by CS78 (edited 4/6/2014 10:20p).]