My apologies for the denseness of this writing.
Sunlight comes to quite different elevations on the northwest and—from my Perch—the far bank of the pool because of the gap the cold tributary creek has over millennia cut in the ridge forming the southeast side of the Steamboat Creek valley in the area of the pool. As circumstances have it at this age of the landscape, the sun and the moon rise pretty much exactly centered in this tributary cleft when viewed from Big Bend Pool. Upstream of the pool proper, the sunlight flooding through this cut strikes the far bank of the creek quite close to the water at least an hour before it does an equivalent elevation on the far bank of the pool. Soaked blue herons and damp turkey vultures now and then take advantage of this early sunlight passing through the tributary gap. They perch on a nearly branchless broken-topped snag centered in a steep grassy slope with thin soils and exposed bedrock here and there. A lush growth of young firs, Oregon grape, ceanothus, service berry, and poison oak form a verge around this grassy opening just above the crowded riparian screening of viburnum, wild rose, nine-bark, sedges, miscellaneous forbs, and alders and dogwoods. This slope is crisscrossed with rotted and fragmenting logs, many of which are the higher parts of the several large snags now standing in this opening.
When this sunlight that slips through the tributary gap finally spreads onto the water, the sunlight directly across the pool from me is still much higher up the far bank of the pool. Until this opposite-bank sunlight moves far enough down the ridge to be reflected on the surface of the pool, the surface of the pool and the slopes around the pool are both in the shadow of the south ridge and all of what is below the surface is visible once the sky turns blue with daylight . . . unless the creek is flowing dirty from a recent rain.
When the earth has rotated enough to allow the sun to rise high enough to cast its light far enough down on the opposite slope to be reflected on a still-shadowed pool—from my perch—the trees and rocks and other vegetation show up as bright colorful reflections upended on the now opaque surface of the pool. The creek has thus become a variably turbulent mirror reflecting the far bank and nothing beneath the surface is visible. These vibrant reflected images last quite a while—for hours once autumn arrives—before sunlight actually creeps out onto the pool and makes what is beneath the surface visible once more. While the pool surface remains in shadow, this vibrant mirror is marked by the spreading rings of steelhead rises and it is rocked by amorphous waves and current lines. Occasionally, a steelhead leaps into existence, but more often just a fin tip momentarily cuts the surface film.
I’d been wading the North Umpqua River for many years before I had my curiosity nudged into existence concerning these vivid far-bank reflections, this when I was fishing the water above William’s Creek from the trail side. I had waded into the river when there were no far bank reflections to speak of. When sunlit reflections first spread over the shadowed river, it is a particularly beautiful phenomenon, but it makes wading treacherous, particularly so because I didn’t know the bed of the river well. My body was cut in half by this fluid mirror and my movement became a blind man’s shuffle and I found myself feeling much more carefully with my feet and my wading staff than I was with my finger on the fly line.
Not yet understanding that the river’s opaque mirroring of the sunny far bank required the river to still be shadowed, I thought and thought, constructing and discarding convoluted hypotheses to explain why the river’s surface had become a perfect, if turbulent, mirror that it was impossible to see through . It took setting up camp at this steelhead refuge pool and spending many early mornings seated and watching the water for me to finally recognize what was happening . . . and then it was absurdly simple if difficult to explain. From the vantage of my perch, the fish were visible through the surface film only when the pool’s surface and the portion of the far bank it reflected were either both shadowed or both sunlit or the pool is sunlit and the far bank shadowed.
The surface of the water serves as an opaque mirror only when the shadow of the southeast ridge still covers the pool, but the sun is illuminating that portion of the far bank that my perch allows me to see reflected on the pool. This is simply a matter of sight lines and angles and where the sun is in the sky in relation to the crest of the southeast ridge behind me as I sit at my Perch.
My enlightenment about this natural phenomenon then led me on to an intriguing understanding of a feature common to all reflections everywhere: whether on a shadowed creek or a mirror on the wall, all reflections are explicitly viewer dependant. Standing ten feet apart on the bank of the pool, myself and another person or a chipmunk or a winter wren, will see the reflection of the same far bank object in different places on the surface of the pool. This also means that the winter wren—or a camera—and I will see different things in the same place on the pool’s surface. How different these mirroring reflections will be for a Steller’s jay and a mouse on the same part of the pool’s surface will depend on how far apart the two creatures are. Thus, when Big Bend Pool is a mirror: reflected images of different things will be in the same place at the same time for two different viewers and the reflected image of the same thing will be in different places at the same time.
To me, this ability of reflections to vary in relation to the position of the observer finally ramified into an awareness of something quite unique to the natural world insofar as I know it. It is that—given a mirroring surface—if no observer is present, there can be no reflections displayed on this reflective surface.
Therefore, a person can ask, “If a tree fell in a forest and there was no creature to hear it, does the falling tree make a sound?” Replace the phenomenon of sound with that of reflections, and a person would have to answer, “No, the reflections don’t and can’t exist in the absence of an observer.”
Take care, go well,
Lee and Maggie
Article photos © Lee Spencer
