You can dig all the material you want either in the creek or on the banks but only pan the material from the creek in the creek in ca. You can not dig material out of the bank and then pan it in the creek but you can run it in recirculation mode using any equip. but now they are trying to say any water you spill or dump from tubs is discharging and they want money for a permit. In non motorized areas you can gravity dredge or gravity high bank as long as it is in the creek by running gravity water to it from long hoses  To high bank make your banker open ended and if you have adjustable legs just set it down in the creek. The loop hole is I believe that there are five pieces to a dredge and if one is missing say the sluice and your pumping into a tank or bucket you are not dredging, or if the motor is missing and your gravity feeding the water in your not high banking  if its in the confine of the creek, no discharge, but do not have the fifth component with you or they will say you are dredging. Tom