Bob K, I do not know of anyone that would bother you with a Gold pan under a bridge except maybe a trooper or sheriff. But I have not checked the laws of all mining or counties for a while. Check with land owners always and mining claims owners are more helpful if you ask, a Gent on Graves creek just off I-5 told me to have at it just below his claim, there was a shale shelf and bedrock ther, so with a face mask, big screwdriver, and bulb sniffer, I pulled 2.55 Troy Oz on a weekend of average match head size nuggets out of there, when I showed the Man He said Thank You, I knew I was loosing gold from my operation, so I looked with him and we found a few items at his Trammel, Grizzly and sluice that were the problem. The Man told me I was Welcome to hunt any of his claims and gave me maps to them(3)...