Gordon Grant is a fluvial geomorphologist and research hydrologist with the Forest Service. He has studied the mechanics of the McKenzie as it comes up against competing demands for the river’s water, from urban to agricultural to habitat use as well as changes in land use and climate change. Grant says the McKenzie’s water flows come from two dramatically different systems in the relatively young High Cascades and in the elderly 10 to 20 million-year-old Western Cascade Mountains. “One of the punchlines I like to use is ‘Geology is destiny,’” he says.