This may sound like a dumb question, but we're planning on a pond for our
backyard
and I keep wondering about overflow.
What happens when it rains?
Does the pond overflow? Or do I need a overflow drain of some sort?
This is going to be a very small pond (3ft x 6ft?)
with a water fall down 3ft to another small pond (same size).

Any suggested sites to help me?

Thanks, Gary.