Thanks ted for that link, this pic is similar to the one I am using http://[Linked Image from i.imgur.com]
You right about low head, I can raise this up about 6" and it will greatly reduce flow, but when I reduce the 3" outlet to 2" it will gain some head.I only use it at water level anyway to push water through a plant island. I have used a troll motor (your propellers in wall idea) that also worked well, just takes more energy. If your creek fills with plants, it might not be a bad thing, they do a good job of cleaning up the water. This might not help you, Just relaying my experiences . Good luck and keep this updated.