you should send it to the Regional Water Quality Control Board in Redding, it is their area of control. It could be from all the geese pooping on the golf course and running off into the stream. I heard it is infested with geese up there on that course. It's good you are reporting this, they need our eyes and ears to report pollution, whatever the source.
I've worked with these guys before, they are
Central Valley RWQCB (5R)
Redding Office
Address: 415 Knollcrest Drive
Redding,CA 96002
Phone: (530) 224-4845
Fax: (530) 224-4857