Every state is very different... In VA the land owner has a lot of protections, other states are more liberal and don't protect the land owner as much. I would personally put a posted sign at least every 30 ft around my pond with No Trespassing, etc. The life ring would be a great idea as RobA said, right underneath and Pond Rules sign. I would photograph all those signs and document where each one is located on and around your pond. It all may seem like a pain now, but when you get sued, you'll be glad you did this. Check with your local game warden or police officer. Most are more then willing to give you free professional advise for your situation... Each state has different laws about trespass, what the definition is and what teh penalties are. A pond that is properly posted, with a life ring left for the safety of those who are legally permitted to use to pond would in my opinion be less liability in a civil case.
