Good luck with that. I know in California the BLM only allows certain things in certain areas that are defined. They know that limiting where you can drive and park, will stop you from whatever that hike up to your destination. Not sure about the rules of dredging, but pretty sure it is considerd as harmful as erosion from dirt bikes, jeeps, etc. They frown on things that may alter the natural run off of streams, etc. I'm sure you have read about the effects of the old hydraulic mining in California. I'll do a little checking with my rock and gem club about dredging, may not be new to you, but I'll ask about it. As I was thinking, you will have many obsticales, and the places you may be planning on the most, like the Placerville region, will be the most restricted. My son in Law also has dreding equipment, I will see what he knows.http://www.goldfeverprospecting.com/casudrredrre.html
The above may not be new news to you, but something I was not aware of because I'm not into it. Hope it helps, but sounds like you may already know about these laws.