oeeh, interesting challenge. I have taken long exposure shots of the sky and of ghost-people but I've never tried water! I'll try to find some relatively fast stream of water. I've looked though your photos multiple times and I just love the high contrast in you black and white shots. There's this Dutch photographer Anton Corbijn who makes black and white portraits with a high contrast as well, so I'd like you to try and use him as an inspiration for your picture. Good luck!