Sand / Water Table - stray cat question

We have a stray cat in our back yard that I notice on occasion.
My mom just told me not to put sand in the table b/c the cat is going to use it as a litter box.
How do I keep this cat away? Should I not put sand in it?

Re: Sand / Water Table - stray cat question

Does it have a cover on it? If it's covered, it will deter the cat from trying it.