Nature Wants to Wiggle
This past Sunday into Monday, we got quite a deluge. Over 3 inches of rain fell, accompanied by gusty winds. On Monday morning as the system was pulling out, I walked out into the street in front of my house. With all the wind and rain, my neighbor’s cherry tree had let loose many pinkish blossoms that the wind piled up along the street’s curbline into a sort of windrow. The runoff from the street flowed down the curbline and created a wiggly pattern through the cherry blossom windrow.
Hmm, I thought, it looks just like a meandering stream valley.
In fact, a short walk from my house, the Rivanna River has a similar meander pattern. Water seems to do this at every imaginable scale.
Water meandering through a cherry blossom windrow. Source: D. Hirschman
The Rivanna River meandering along the City/County line. Source: Google Earth
As for the cherry blossom stream, I wondered why, if the curb provided the water a straight-line path to follow, did it decide to meander instead? I know my stream restoration friends have computations that can answer this question mathematically. The solution lies in fluid mechanics, hydraulics, perhaps the Bernoulli Equation, and the mish-mash of gravity, geology, particle transport. . .and the frictional forces of cherry blossom petals.
Beyond computations, there is also the mystery of patterns. We can forgive ourselves if life seems to be meandering rather than proceeding in straight-line fashion – it is only natural!
The Rivanna River meandering along the City/County line. Source: Google Earth
Another example of nature meandering at scale — the atmospheric river. Source: NOAA Satellite and Information Service
A poem by Kenton M. Stewart, The River That Meanders, explores the story of meandering rivers with all their mystery and language of pattern. Stewart is a professor in the Department of Biological Sciences, State University of New York at Buffalo.
I wish you fruitful meanderings.