Yesterday, BLM changed the rules to make it easier to mine on public lands near the Grand Canyon. Today, EPA designated two sections of the normally-dry Santa Cruz River [right, credit, AZ Dept of Water Resources] as navigable and thus subject to the Clean Water Act rules.
If there's any kind of pattern in here, it's beyond my ability to see it.
The two sections of the river that flow year-round do so only because wastewater treatment facilities pump their effluent into it. One section runs from from Tubac to Continental Road in Tucson, and the other from the Roger Road sewage- treatment plant to the county line.