We shot this in my studio straight after a water workshop session.
I made a timber frame and I lined the wall and floor with black plastic and then filled the very shallow pool with about 30mm of water.
I setup a 1.2m octagonal softbox on a large boom directly above her and then had my assistant spray her with a hose to get the rain effect.
Lucky for us we were in the Summer season and it turned out to be about 37°c on the day.