Agreed kinda,i lived in summit county Colorado many years,we had plenty of confrontations with land owners on the Colorado river and the Blue river south of silverthorn,all private all the way to Kremlin where the blue dumps into the colorado river,long stretch of class 5 trout waters,we were young rafting these waters and snubed our noses at these crabby ranchers as our rafts certainly didn't leave a foot print on these water ways...,infact fishermen sneaking in by land,caught and tagged by local enforment,so yes Colorado water ways are private unless one is savy enough to locate land owner miles away,no computers back then to help in locating said land owners,we had our ass chewed rafting fishing the snake river in wyoming once and that was enough,rancher got irrate,hostel even i recall.
Seems every nook and cranny is private these days.