What are you planning to put around the pool? I would just put that all the way around the pool and push it out so that it fills in between the fence and pool wall. I would have it level with the ground instead of trying to build it up to the top to meet the coping.
OR you can spend some bucks and make it level with the coping all the way around and make that area behind the water feature a seating area. You will want to make the side of it pretty. You will also want some steps to get up on it.
There are many things/ways you can do it. Look at it with these ideas in mind and let us know what you are thinking.
Those hands prints:angel: SO sweet!