Are you crazy? Shooting at the waters surface is just as dangerous (if not more) than shooting at the surface of the land. Bullets can and do glance off these surfaces and can travel upwards to over a mile away. I'm sure you're not interested in accidently killing someone over a muskrat. If you're going to shoot on the water, use a shotgun as others have suggested. Not a single projectile bullet, especially a 22 cal. People get shot and/or killed every year by stray bullets. Use common sense and make sure you have a solid backstop.
Last time I checked I was'nt crazy, are YOU???????????
We have everything UNDER CONTROL at my buddies place. If ya don't know the specific circumstance of a situation, DON'T SPECULATE. You sound like the News Media Jackals.