It is camping along the river in Russia – not a paid site – legal?

I am planning a camping trip and canoeing on the Russian River County Sonoma, California. I do not want to stay at a public (fee) site but rather want to camp along the river or a river island. I know that the land is public – but is it legal?

No, it is not. There are a couple of spots on the river that are privately owned where you can do that, but you still must register and pay.

Russian River Canoeing