Check out the other thread regarding this subject. Just gotta give em time. It helps to have another dog when your introducing the dog to swimming. Creates a friendly competition. Even if your dog won't follow the other one in, she'll watch with an unimaginable intensity. This will teach her that it's FUN to swim! After a few months, you won't be able to get her out of the water.
I know that it's the wrong time of year, but I bought my pup a kiddie pool the day after I brought him home. After three and a half years, he still LOVES that damn pool! I believe that he started to regard water as an everyday thing. The more familiar something is, the more natural it is when they encounter it outside their territory.
My 2 cents....
My girlfriend's dad has a five acre duck marsh. I'm in love. (2008-2009)
My new girlfriend's dad is an outboard motor mechanic. I'm in love. (2010-12)
My new girlfriend's dad has a lakehouse. I'm in love. (2013-15)
F*** it...buying a dog. (2015-death)