Hmm, I think it would be wise for me to study my site for a few months before committing to a plan of action. Most of what I am telling you regarding the flow over the year is from memory. I think it would be good to actually measure the flow through spring to summer at regular intervals. Hydrosun, from what you are telling me , this could be extremely expensive. I also don't want to take all the water from the river and dramatically change the ecosystem. We have trout, crayfish, otters, ducks, and herons - and that's just the wildlife I've seen along this 150 yard stretch. I think I should weigh the pros and cons of any system before building anything. Thanks for your advice.