Scroll through the west side river regs and look at the names in there.....if it's got any special regs, it's got fish in it (or, rather, it's supposed to.) If it's in Snohomish county and you can figure out where it is, give it a whack.

I've never tried French Creek, but it looks NASTY right before they lift it into the Snohomish. How far up do you fish it? (nothing specific...don't wanna step on your zipper. )