Fisthead,

It sounds like you're figuring out the depth the only good way, which is by trial and error. Unfortunately the trial involves hitting the bottom with your lure, and it's snaggy enough that it involves losing your spinners.

Try using some drift gear, perhaps with a slinky, and you'll get a better feel for the depth of where you're fishing without losing so much stuff.

Other than that, there's not really any other way to determine the depth, unless you can either see the bottom or can see the area during extremely low flows and remember what it looked like when the water returns.

Here's a trick I used on a few small streams when I was learning them back in high school. I'd float stretches of the streams in an inner tube in August, using a Polaroid camera to take pictures of deeper slots, big rocks, and permanent looking logs. Mark on the pictures where they came from. In the winter/fall go back and look at the area. You'll be surprised at how different it looks with water over it.

At least you'll know the relative depth of those spots and the breaks in structure that attract holding fish, and the runs that attract moving fish. Invaluable information.

Fish on...

Todd.