Unhappiness After Stream in Montana Is Open to All A group of landowners, including several wealthy out-of-staters, are none too happy that their exclusive use of a scenic trout-rich stream in the Bitterroot Valley is coming to an end. The Montana Supreme Court ruled here recently that the 16-mile-long stream, Mitchell Slough, is open to the public and that the landowners are not entitled to fence it off as part of their private sanctuaries. Montana law is firm in allowing the public access to streams and rivers that flow through private land, up to the high-water mark. The law states that fishermen can walk in a stream or along the bank up to the high-water mark if they enter the waterway from public land like a bridge. They may not cross or walk on private land above the mark without permission. In this case, though, two dozen landowners — including the rock singer Huey Lewis and Charles R. Schwab, founder of the brokerage firm that bears his name — argued that irrigation diversions had so thoroughly altered Mitchell Slough that it was no longer a natural waterway and that therefore the stream access law should not apply. To reinforce that belief, they began calling it Mitchell Ditch. But in a unanimous ruling, the State Supreme Court here ruled that in spite of the changes, the slough was still a “natural perennial flowing stream” and public access was warranted....