My dog is crazy in our pool?

I have a black mini poodle, and she is 10 yrs old. She does the weirdest things in my family's pool. At first she would bark and obsess over anything floating in the pool. Then she started to get on the floats and everything. Then she started digging. This is the trouble part,she digs for hours on end, literally. She just sits there and digs. Recently she has started biting the water and sticking her head under while biting. She seems to really enjoy doing those things. What the heck is my dog doing? And does anyone know how to make her not as obsessed about it? Im glad she likes the pool, but this is insane!