I arrived in Missoula, Montana on the 4th of May. The Clark Fork River was entering flood stage, eventually cresting at levels not seen in the region for over 100 years. The river went up, then down, only to flood again a few weeks later. Now? Now the river is low, resuming a summer flow that is slow, lazy, and filled with rafts, kayaks, and inner tubes as people from near and far float down to Missoula. This is the river in a dry land, quick and flashy, running high and then running low. Rivers running through wetter climes are slower to build their floods and more reluctant to let the water go.
I experienced the 500 year flood on the Missouri River in 2011, having to change my travel plans again and again as the River overcame highways, back roads, and bridges. These two rivers behaved so differently in flood stage: the Clark Fork was aggressive, full of energy, violent even, a river to fear; the Missouri just spread out, full of silt, slowly settling downstream, reaching for the Gulf of Mexico so far away. But appearances are deceiving. The Clark Fork has little chance of eroding the Pre-Cambrian rocks of its bed no matter how fast it flows, whereas the Missouri has been rearranging its wide, meandering flood plain with each year’s runoff since before the last period of glaciation.
Rivers run through landscapes, linking water to air, linking the aquatic and terrestrial environments. When they flood, they leave behind the aquatic environment even as they carry away a part of the terrestrial environment, mixing both. My new home is a mile from the Clark Fork River and was built atop several feet of cobble and gravel from floods of springtime past. The world around me was formed by the creative forces of the river, carving out rock, bending time. The land I left behind, soft land near the Missouri River, was shaped more by glaciers grinding rock into Loess, water gently winding through this soft soil. Now that land is carved by the combine and the tile, driving streams deep into dirt, creating canyons of mud. In moving from the Great Plains to the Western Rockies, I have left one water shaped world for another.
If we look around us, look around us now, we will see that all of our landscapes, internal and external, have been shaped by water, by the flowing of rivers, by the tethysphere.