I can never find the right snake picture

My neighbor and I just relocated a black snake with a yellow belly that
was making a home out of our garden storage box. It was pretty long,
maybe 30", but not very thick. I'd be surpised if it was even and inch
and a half. It wasn't heavy-bodied and didn't have a stubby tail, so I
kind of ruled out a cottonmouth. I don't think it was big enough to
eat my fish, but I still didn't want it in my pond. The only thing
questionable about it is that its head was a bit triangular shaped, but
I certainly didn't get a look at its pupils. The head shape has been
completely unreliable for me as an indicator of the type of snake,
since the only snake I've ever seen in our yard that didn't have a
triangular head is a green grass snake. And yet, I know that most of
those snakes were not poisonous. This was probably one of those black
water snakes. I don't want him around, but I get so grossed out at the
crunching involved in cutting their heads off. I will say that if he
comes back, DN and I have agreed that all bets are off, and he will
have to be dispatched. His kids will be staying here during the day
once school is out, so he kind of cares whether we have snakes in our
yard. Do you think he will come back, if he is a water snake? We only
took him about 75 yards down the street and tossed him over the fence
into a wooded vacant lot. Do you think he's gone?