Thanks for the input folks.
I plan to check out the links for more information. I am in my mid 70s so for me this is a BIG project even though my creek bed is shallow and not very wide. It does work - the last heavy rain went down my trench instead of across the yard.
I dig a few feet every morning before it gets too hot and the next day place my weed block and stones. (I only have about 35 - 40 feet to dig.)