I get many letters asking how to catch and kill a snake in the pond. We build these backyard resorts for wildlife and then want to make a gated community out of that resort. Snakes are much more afraid of you than you are of them. There are only a few poisonous snakes and even those are afraid of you. If you must rid your pond of snakes, you can probably catch them in a net and relocate it in nearby water.
Remember snakes eat toads, frogs, rats, mice, bugs and all matter of nasty vermin. Be glad to have snakes in your pond.
Remember, there is no such thing as one snake.