Want to let my dog swim more but where???

We really don't live that close to any bodies of water that the dog can swim in and don't know anyone with a pond yet. I am going to dock diving practive today and hope to maybe meet someone with a pond or learn of more places she can swim. They dont make dog proof kiddie pools in a size that really fits a german shepherd, at least not around her all I have is a little plastic one. I can not dig a pond in my yard because it is not big enough and I rent until I can save up enought to get a house with acerage. When that happens we will have a doggie play yard complete with all kinds of fun stuff.