Pretty interesting stuff. With regards to the current law (or lack there of):
I think the Denver Post article sums it properly:
The courts and the legislature decades ago decided and re-decided the right-to-float issue on the criminal side, and it's not a crime to pass through private property on a river.
But in the past three decades, there has been no such definitive answer for whether floaters can be sued for civil trespass if they float through private land.
There was a discussion about this a while back. Take a look at Caspian's response on page 2 - it offers a pretty good explanation of the current lack of clarity in Colorado law.
Right to float issue heating up in Steamboat Springs.
It's very frustrating and I agree it would be nice if we would just pass a law that grants river users passage and clearly defines the terms.
It's times like this that it helps me to remember how many great landowners there are out there even though it only takes one to ruin things. I think of the property owner on Bailey who owns the property by Four Falls. Despite a fairly large amount of traffic on that land there are been minimal issues with people portaging 4 falls. Whenever I've seen people there, people have always been friendly and frequently want to stop and watch the boaters run the drops. Then there were some landowners on the Big T. that helped retrieve a boat and offered to stash it in their yard until it could be picked up. Sorry for the diversion, just trying to convince myself that humanity is not necessarily doomed.