Still Waters - Mathematics and Statistics for the Environment - page 571

20 Still Waters
Consider a river pool, isolated by fluvial processes and time from the main stream flow. We are
immediately struck by one overwhelming impression: It appears so still … so very still … still
enough to soothe us. The river pool provides a kind of poetic solemnity, if only at the pool's surface.
No words of peace, no description of silence or motionless can convey the perfection of this place,
in this moment stolen out of time.
We consider that the water is still, but does the term still correctly describe what we are viewing?
Is there any other term we can use besides still —is there any other kind of still? Yes, of course, we
know many ways to characterize still. Still can mean inaudible, noiseless, quiet, or silent. Still can
also mean immobile, inert, motionless, or stationary—which is how the pool appears to the casual
visitor on the surface. The visitor sees no more than water and rocks.
The rest of the pool? We know very well that a river pool is more than just a surface. How does
the rest of the pool (the subsurface, for example) fit the descriptors we tried to use to characterize its
surface? Maybe they fit, maybe they don't. In time, we will go beneath the surface, through the liquid
mass, to the very bottom of the pool to find out. For now, remember that images retained from first
glances are almost always incorrectly perceived, incorrectly discerned, and never fully understood.
On second look, we see that the fundamental characterization of this particular pool's surface
is correct enough. Wedged in a lonely riparian corridor—formed by a river bank on one side and
sand bar on the other—between a youthful, vigorous river system on its lower end and a glacier-
and artesian-fed lake on its headwater end, almost entirely overhung by mossy old Sitka spruce, the
surface of the large pool, at least at this particular location, is indeed still. In the proverbial sense,
the pool's surface is as still and as flat as a flawless sheet of glass.
The glass image is a good one, because like perfect glass, the pool's surface is clear, crystal-
line, unclouded, definitely transparent, and yet perceptively deceptive as well. The water's clarity,
accentuated by its bone-chilling coldness, is apparent at close range. Further back, we see only the
world reflected in the water—the depths are hidden and unknown. Quiet and reflective, the polished
surface of the water perfectly reflects in mirror-image reversal the spring greens of the forest at the
pond's edge, without the slightest ripple. Up close, looking straight into the depths of the pool we
are struck by the water's transparency. In the motionless depths, we do not see a deep, slow-moving
reach with the muddy bottom typical of a river or stream pool; instead, we clearly see the warm var-
iegated tapestry of blues, greens, blacks stitched together with threads of fine, warm-colored sand
that carpets the bottom, at least 12 feet below. Still waters can run deep.
No sounds emanate from the pool. The motionless, silent water does not, as we might expect, lap
against its bank or bubble or gurgle over the gravel at its edge. Here, the river pool, held in tempo-
rary bondage, is patient, quiet, waiting, withholding all signs of life from its surface visitor.
Then the reality check: This stillness, like all feelings of calm and serenity, could be fleeting,
momentary, temporary, you think. And you would be correct, of course, because there is nothing
still about a healthy river pool. At this exact moment, true clarity is present, it just needs to be per-
ceived … and it will be.
We toss a small stone into the river pool and watch the concentric circles ripple outward as
the stone drops through the clear depths to the pool bottom. For a brief instant, we are struck by
the obvious: The stone sinks to the bottom, following the laws of gravity, just as the river flows
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