FYI, I lived in Oakdale for 18 years. There is a series of parks along Orange Blossom/Rodden and River Road all the way down the Stanislaus. There are many with good sand/ gravel banks that get refreshed every year with the high flow water flow. There is also an old sand/gravel pit along Rodden Road as well. You can pick up a location map to these at any of the park entrances or the ranger station in Knights Ferry. There is one park just west of McHenry that I haven't tried but it's on my list. When I was there a month or so ago the inside bank was completely out of water and the river only ran on the outside curve about 30 ft wide and shallow. The exposed inside bank ran well over 100 yards and looked interesting after the fall/spring run off. They let a large amount of water out of Tulloch for the Salmon run between Oct and Jan. I have never seen anyone down that way doing any prospecting so who knows? I don't know what the river flow is now and it may be back under water. I live up the hill around Lake Tulloch and don't go that way much anymore. There is still too much gold waiting up this way that is saying come find me. If you'd like more info PM me and I'll be glad to give it. Good Luck Fellas!
