Science of Water : Concepts and Applications

Water Ecology 173
dark winter months, but with longer, warmer spring days, the sun is higher, more direct, and of longer
duration, and the frozen masses of water respond to the increased warmth. The melt begins with a
single drop, then two, then increasingly more. As the snow and ice melts, the drops join a chorus that
continues unending; they fall from their ice-bound lip to the bare rock and soil terrain below.
The terrain the snow-melt strikes is not like glacial till, the unconsolidated, heterogeneous
mixture of clay, sand, gravel, and boulders, dug-out, ground-out, and exposed by the force of a
huge, slow, and inexorably moving glacier. Instead, this soil and rock ground is exposed to the falling
drops of snow-melt because of a combination of wind and the tiny, enduring force exerted by
drops of water as over season after season they collide with the thin soil cover, exposing the intimate
bones of the Earth.
Gradually, the single drops increase to a small rush—they join to form a splashing, rebounding,
helter-skelter cascade, many separate rivulets that trickle, then run their way down the face of
the granite mountain. At an indented ledge halfway down the mountain slope, a pool forms
whose beauty, clarity, iciness, and pure sweet taste provide the visitor with an incomprehensible,
incomparable gift—a blessing from the Earth.
The mountain pool fi lls slowly, tranquil under the blue sky, refl ecting the pines, snow, and sky
around and above it, an open invitation to lie down and drink, and to peer into that glass-clear, deep
phantom blue-green eye, so clear that it seems possible to reach down over 50 feet and touch the
very bowels of the mountain. The pool has no transition from shallow margin to depth; it is simply
deep and pure. As the pool fi lls with more melt water, we wish to freeze time, to hold this place
and this pool in its perfect state forever, it is such a rarity to us in our modern world. However, this
cannot be—Mother Nature calls, prodding, urging—and for a brief instant, the water laps in the
breeze against the outermost edge of the ridge, then a trickle fl ows over the rim. The giant hand of
gravity reaches out and tips the overfl owing melt onward and it continues the downward journey,
following the path of least resistance to its next destination, several thousand feet below.
When the liquid overfl ow, still high in altitude but its rock-strewn bed bent downward, toward
the sea, meets the angled, broken rocks below, it bounces, bursts, and mists its way against steep,
V-shaped walls that form a small valley, carved out over time by water and the forces of the Earth.
Within the valley confi nes, the melt water has grown from drops to rivulets to a small mass of
fl owing water. It fl ows through what is at fi rst a narrow opening, gaining strength, speed, and power
as the V-shaped valley widens to form a U shape. The journey continues as the water mass picks up
speed and tumbles over massive boulders, and then slows again.
At a larger but shallower pool, waters from higher elevations have joined the main body—from
the hillsides, crevices, springs, rills, and mountain creeks. At the infl uent poolsides, all appears
peaceful, quiet, and restful, but not far away, at the effl uent end of the pool, gravity takes control
again. The overfl ow is fl ung over the jagged lip, and cascades downward several hundred feet,
where the waterfall again brings its load to a violent, mist-fi lled meeting.
The water separates and joins repeatedly, forming a deep, furious, wild stream that calms
gradually as it continues to fl ow over lands less steep. The waters widen into pools overhung
by vegetation, surrounded by tall trees. The pure, crystalline waters have become progressively
discolored on their downward journey, stained brown-black with humic acid, and literally fi lled
with suspended sediments; the once-pure stream is now muddy.
The mass divides and fl ows in different directions, over different landscapes. Small streams
divert and fl ow into open country. Different soils work to retain or speed the waters, and in some
places, the waters spread out into shallow swamps, bogs, marshes, fens, or mires. Other streams
pause long enough to fi ll deep depressions in the land and form lakes. For a time, the water remains
and pauses in its journey to the sea. However, this is only a short-term pause, because lakes are only
a short-term resting place in the water cycle. The lake water will eventually move on, by evaporation
or seepage into groundwater. Other portions of the water mass stay with the main fl ow, and the
speed of fl ow changes to form a river, which braids its way through the landscape, heading for the
sea. As it changes speed and slows, the river bottom changes from rock and stone to silt and clay.