motion sensor sprinkler
Get a motion activated sensor attached to a garden hose from a diy store. The kitties do not like a baths...or showers. Another benefit is your garden/yard gets watered.
Have you talked to the owners of these cats or are they feral?
Try putting out pans of vinegar and/or wet coffee grounds. They don't like the smell.
Here are some tips: https://davidsuzuki.org/queen-of-green/keep-cats-garden/
I work at an animal shelter and swear by this tip......place lemon, lime and orange peels in your garden. Cats hate the smell of citrus and will stay away. Makes a great fertilizer, too!