River basin

“ Every brook and every creek is made up of water that falls near it, and rivers are made of the water poured into them by brooks and creeks. A river and all the streams that carry their water into it make a river system, and the land from which they drain the water is called the river basin. ”

“ This Great Basin is yet to be adequately explored. And here, on quitting the banks of a sterile river, to enter on arable mountains, the remark may be made, that, on this western slope of our continent, the usual order or distribution of good and bad soil is often reversed; the river and creek bottoms being often sterile, and darkened with the gloomy and barren artemisia; while the mountain is often fertile, and covered with rich grass, pleasant to the eye, and good for flocks and herds. ”

“ Back of the granite barriers the river spread right and left, and then went out to sea in a deep and narrow stream, curiously free from ice. Indeed, there was but little ice in the main basin, and a kind of steam hung over it so that the Poor Boy was compelled and delighted to conclude (with the aid of his companions) that the river toward its mouth must be swollen by warm springs. ”

“ This is the case with the Tay, Forth, Tweed, Tyne, Humber and Thames, the Clyde and Severn being the most remarkable exceptions to this direction. The whole extent of country from which a river receives its supply of water, by brooks and rivulets, is termed its basin, because a region generally bounded by a rim of high lands, beyond which the waters are drained off into another channel. The basin of a superior river includes those of all its tributary streams. ”

“ River basins vary in extent according to the configuration of the country, ranging from the insignificant drainage-areas of streams rising on high ground very near the coast and flowing straight down into the sea, up to immense tracts of great continents, when rivers, rising on the slopes of mountain ranges far inland, have to traverse vast stretches of valleys and plains before reaching the ocean. ”

“ In rising one foot a lake may store away more water than the river by its consequent rise at the point of outflow will carry away in many months, and this for the simple reason that the lake may be many hundred or even thousand times as wide as the stream. Moreover, as before noted, the sediment gathered by the stream above the level of the lake is deposited in its basin, and does not affect the lower reaches of the river. ”

“ It was the river flowing thus on higher ground that made irrigation and reclamation of the desert possible. It was this also that made possible the disaster that was now upon the hardy pioneers, who had staked everything in their effort to realize the vast potential wealth of the ancient sea-bed. The grade from the river at the intake to the lowest point in the bottom of the Basin is much steeper than the established fall of the river from the intake to the gulf. ”

“ The height of their situation is not connected with their magnitude; the smaller ones alone appear sometimes a little worn, but the large ones are not so at all. Those which belong to the basin of each river are found, upon examination, to be of the same nature as the mountains of the tops or sides of the high valleys in which the tributary streams of this river take their rise. ”

“ It is because of this progressive reduction of grades with increasing age that the early stages of a river’s life are much the most turbulent of its history. The water then rushes down the steep grades in rapids, and is often at times opened out in some basin to form a lake where differences of uplift have been characteristic of neighboring sections. ”

“ The basin is mostly circular, sending out a constant stream into the river fifteen yards wide, and ten or twelve in depth. The basin and stream are both peopled with prodigious numbers and variety of fish and other animals, as the alligator, manatee, or sea-cow, in the winter season: part of the skeleton of one, which the Indians had killed last winter, lay upon the banks of the spring; the grinding teeth were about an inch in diameter, the ribs eighteen inches in length, and two inches and a half in thickness, bending with a gentle curve—these bones being esteemed equal to ivory. ”

“ The old bends of the river, half or wholly shut off, form lagoons, which serve as mighty reservoirs and draw off immense quantities of water, so that the régime of high waters commences in the lower basin much later than in the upper part of the river. ”

“ This basin, with that of the Greenbrier on the other side of New River, forms the broadest stretch of cultivated land found between the mountain ranges, though the whole country is rough and broken even here. ”

“ Another class of lake basins occurs in valleys, the basins being partly rock and partly drift. If a thick deposit of drift be made at one point in a valley, while above there is little or none, the thick deposit will form a dam, above which waters may accumulate, forming a pond or lake. Again, a ridge of drift may be deposited in the form of a curve with its ends against a rock-ridge, thus giving rise to a basin. ”

“ VESTY OF THE BASINS
I THE MEETIN'
Now is it to be rain or a storm of wind at the Basin?
I love that foam out on the sea; those boulders, black and wet along the shore, they are a rest to me; the clouds chase one another; in this dim north country the wind is cool and strong, though it is now midsummer; at sunset you shall see such color!
From a little, low, storm-beaten building comes the sound of a fog-horn. That is the gift of Melchias Tibbitts, deceased, to the Basin school-house. ”

“ Beyond this innermost space, round a basin of rock, through which the stream overflowed as from an artificial conduit, lay the wounded and exhausted, crawling, turn by turn, to the lips of the basin, and happy that the thirst of fever saved them from the gnawing desire of food. ”

“ Thus a small rapid stream with abundance of loose transportable material within its reach may fill up an extensive basin in a few centuries, while a large perennial trunk stream, flowing over clean, enduring pavements, though ordinarily a hundred times larger, may not fill a smaller basin in thousands of years. ”

“ Now suppose the water basins which hold the lakes to be over a thousand fathoms (six thousand feet) deep. We know they are not more than four hundred and twenty feet deep; but suppose them to be six thousand feet deep. The process of evaporation, after the St. Lawrence has gone dry, might go on until one or two thousand feet or more were lost from the surface, and we should then have another instance of the level of an island water-basin being far below the sea-level, as in the case of the Dead Sea; or it would become a rainless district, when the lakes themselves would go dry. ”

“ Observation on an unprotected surface after a heavy rainfall will illustrate another point which is of much interest in connection with the work of rivers. This is that the water has most excavating power, not, as might be supposed, in the collecting basin, but in the valley region, where the slope is still great, where the volume of the water is at its maximum, and where it has acquired a load of débris by means of which it carves out its bed. ”

“ But the occasion justified our eagerness. A smooth silicious basin, seventy-two feet in diameter and four feet deep, with a hole at the bottom as in a washing-basin on board a steamer, stood before us brimful of water just upon the simmer; while up into the air above our heads rose a great column of vapour, looking as if it was going to turn into the Fisherman's Genie. The ground about the brim was composed of layers of incrusted silica, like the outside of an oyster, sloping gently down on all sides from the edge of the basin. ”

“ The banks of the stream are sandstone and sand, and the channel scarcely three yards wide, with a strip of grassy thicket twenty yards in width along the stream, which is the only feed near the river, as the plain through which it runs produces nothing but scrub and banksia with a few grass-trees. ”

“ Whether a river begins its life on a lake plain, as in the example just cited, or upon a coastal plain lifted from beneath the sea or on a spread of glacial drift left by the retreat of continental ice sheets, such as covers much of Canada and the northeastern parts of the United States, its infantile stage presents the same characteristic features,—a narrow and shallow valley, with undeveloped tributaries and undrained interstream areas. Ground water stands high, and, exuding in the undrained initial depressions, forms marshes and lakes. ”

“ Turning now to the question of how lake basins are formed, we note a great variety in the conditions which may bring about their construction. The greatest agent, or at least that which operates in the construction of the largest basins, are the irregular movements of the earth, due to the mountain-building forces. Where this work goes on on a large scale, basin-shaped depressions are inevitably formed. If all those which have existed remained, the large part of the lands would be covered by them. ”

“ This is the spring and that upper reservoir, and this lower one is a natural dry basin up there under that bluff, a little to the left of those granite chimneys; you can see its rocky rim. All it needs is this short flume sketched in here to bring the water down, and a sluice-gate to feed the main canal that follows this bench we are on. Spillways would irrigate a peach orchard along this slope below us and seep out through this level around us to supply home gardens and lawn. Just imagine it! ”

“ Every stream has its load of sediment, as the silt- and sand-filled reservoirs along the edges of the valley so effectively testify. Each sandy river bed is an aggregate of rolling grains, moving with the current, slow where it is slow and faster where the current is accelerated, but travelling always towards the sea. ”

“ The minor channels, blocked with driftwood which formed natural rafts; the sand-bars and mud-banks; the great curves of the river, the "bayous" [114] and isolated pools; the natural banks built up by the sediment arrested at flood-time by the herbage near the river brink; the floating timber and the "snags"—all provided valuable illustrations of the physical [Pg 163] features of a great river delta, and supplied him with material which afterwards was worked up into newer editions of the "Principles" and the "Elements." ”

“ If a lake, for example, be encircled on two sides by lofty mountains, receiving from them many rivers and torrents of different sizes, and if it be bounded on the other sides, where the surplus waters issue, by a comparatively low country, it is not difficult to define some of the leading geological features which must characterize the lacustrine formation, when this basin shall have been gradually converted into dry land by the influx of sediment. ”

“ As a river advances toward maturity the initial depressions, the lake basins of its area, are gradually effaced. By the furrowing action of the rain wash and the head ward lengthening, of tributaries a branchwork of drainage channels grows until it covers the entire area, and not an acre is left on which the fallen raindrop does not find already cut for it an uninterrupted downward path which leads it on by way of gully, brook, and river to the sea. The initial surface of the land, by whatever agency it was modeled, is now wholly destroyed; the region is all reduced to valley slopes. ”

“ The water is agitated in the basin, it boils up suddenly, subsides, the earth beneath our feet trembles and a mass of steaming water rises in the center of the basin to an elevation of fifteen feet and overflows the rim with a noisy splash. ”

“ Here is the fashion in which a mountain stream gets down from the perennial pastures of the snow to its proper level and identity as an irrigating ditch. It slips stilly by the glacier scoured rim of an ice bordered pool, drops over sheer, broken ledges to another pool, gathers itself, plunges headlong on a rocky ripple slope, finds a lake again, reinforced, roars downward to a pot-hole, foams and bridles, glides a tranquil reach in some still meadow, tumbles into a sharp groove between hill flanks, curdles under the stream tangles, and so arrives at the open country and steadier going. ”

“ Between the watersheds are hundreds2 of little streams and rivers. To get from the basin of one stream to that of another is so difficult, except along the coast, that each basin forms, as it were, a little world in itself. ”

“ Compared with the former, these recent formations are of very limited extent; they consist of the sand and stones that are accumulated on the sea coast by tides and currents; of the land washed away from one bank of a river, and thrown up on the opposite bank by the winding stream; of the earth and gravel, and fragments of rock, carried down by all rivers, and forming deposits at their mouths; and of the constant increase of marsh land, in consequence of the growth of aquatic plants. ”

“ By means of conduits cut in the living rock, they had managed to lead the water of the stream to a series of basins cut one below the other. The sketch we reproduce shows the lowest basin, which is close to the path. ”

“ Innumerable streams flowing from the mountains to the central plateau, magnificent lakes, the sources of grand rivers, and a river system divided into four drainage basins, make the region singularly well suited for fish life. Exploration soon developed the fact that, while many of these rivers and lakes abounded in trout, others, above the waterfalls which form so characteristic a feature of the streams between the plateau and the lowlands, were wholly destitute of fish. ”