Most of the mills are situated on the banks of the watercourses in the neighbourhood of the town.
It is easy to distinguish the great primitive watercourses from the lateral ducts which they fed, the latter being almost without banks and merely traceable by the winding curves of the layers of alluvium in the bed, while the former are hedged in by high banks of mud, heaped up during centuries of dredging.
The region of dense forest, however, does not cover the whole of Liberia; the Makona river and the northern tributaries of the Lofa and St Paul's flow through a mountainous country covered with grass and thinly scattered trees, while the ravines and watercourses are still richly forested.
There are no bridges, except where watercourses occur.
The reckless destruction of forests along the watercourses also adds to the barren aspect of the country.
The broad watercourses 1 On the alteration of streets alone $26,691,496 were expended from 1822 to 1880.
His knowledge of hydraulics caused him to be frequently consulted with respect to the management of canals and other watercourses in various parts of Europe.
It prefers rich fertile soil on the banks of watercourses, but does not flourish in swamps.
The scenery in this mountain region is of the most varied description; bare precipitous hill-sides seamed with dry, rocky watercourses give place with almost startling rapidity to fertile slopes, terraced literally for thousands of feet.
The Arhab district, through which these two great wadis run, was formerly the centre of the Himyar kingdom; cultivation is now only to be found in the lower parts on the borders of the watercourses, all above being naked rock from which every particle of soil has been denuded.
Nevertheless, all this southern district of Tunisia bears evidence of once having been subject to a heavy rainfall, which scooped out deep valleys in the original table-land, and has justified the present existence of immense watercourses - watercourses which are still, near their origin, favoured with a little water.
The territory is covered with dense forests and is filled with intricate watercourses, one of which, the Casiquiare, forms an open communication between the Orinoco and the Rio Negro and is navigable for large canoes.
The western half of these plains has only a few trees along the watercourses and some scraggy bushes of oak, juniper and cedar in the more hilly sections.
The pine and hardwood forests are of great economic value because of the density of their growth, and there are at hand the means of profitable development of this industry in the numerous watercourses which make logging cheap and expeditious.
As the mountains of Valencia and Catalonia effectually bar out the fertilizing moisture of the sea-winds, much of the province is a sheer wilderness, stony, ash-coloured, scarred with dry watercourses, and destitute of any vegetation except thin grass and heaths.
The climate is so dry, and the rains are so scarce, that an absence of forests and Alpine meadows is characteristic of the ridge; but when heavy rain falls simultaneously with the melting of the snows in the mountains, the watercourses become filled with furious torrents, which create great havoc. The main glaciers (12) are on the north slope, but none creeps below io,000 to 12,000 ft.
The upper Mississippi and some of the Ohio basin is the prairie region, with trees originally only along the watercourses; the uplands towards the Appalachians were included in the great eastern forested area; the western part of the plains has so dry a climate that its herbage is scanty, and in the south it is barren.
The watercourses to-day are, as a rule, longitudinal, following the strike of the weaker strata in paths that they appear to have gained by spontaneous adjustment during the long Mesozoic cycle; but now and again they cross from one longitudinal valley to another by a transverse course, and there they have cut down sharp notches or water-gaps in the hard strata that elsewhere stand up in the long even-crested ridges.
The till plains, although sweeping in broad swells of slowly changing altitude, are often level to the eye, and the view across them stretches to the horizon, unless interrupted by groves of trees along the watercourses, or by belts of low morainic hills.
Almost all of the United States east of the 98th meridian is naturally a forest region, and forests cover the greater part of the Rocky Mountains, the Cascades, the Sierra Nevadas and the Coast Range, but throughout the belt of plains, basins and deserts west of the Rocky Mountains and on the Great Plains east of the Rocky Mountains there are few trees except along the watercourses, and the prevailing type of vegetation ranges from bunch grass to sage brush and cactuses according to the degree of aridity and the temperature.
Owing to this configuration of the island the watercourses of the western side are comparatively short: only very few of them are large enough to be navigable.
Though there are no perennial rivers, there are watercourses (khors or wadis) in the rainy season; the chief being the Khor Abu Habl, which traverses the southcentral region.
The earliest rain that fell upon these ridges would run off them, first in transverse watercourses down each short slope, and then in longitudinal depressions wherever such had been formed during the terrestrial disturbance.
Moreover it is of a most disagreeable kind, as the waste "still-liquor," containing very much free hydrochloric acid and even some free chlorine, forms a most deleterious impurity when finding its way into drains or watercourses, apart from the intolerable nuisance caused by the escapes of chlorine from the stills and otherwise, which cannot be at all times avoided.
The sanjit (Elaeaguns orientalis), common on the banks of watercourses, furnishes an edible fruit.
Very similar operations have been carried out in Austria-Hungary, where large tracts of land have been brought into cultivation, and watercourses have been diverted successfully despite serious difficulties, climatic and physical; in Russia convict labour has been largely used in the construction of the Trans-siberian railway; the military operations in the Sudan were greatly aided by convict labourers engaged in useful work at the base and all along the line; Italy passed a law in 1904 enacting outdoor labour for the reclamation and draining of waste lands by prisoners under long sentence; and France, although much wedded to cellular imprisonment, is beginning to favour extra-mural employment of prisoners under strict regulations.
Assam is a fertile series of valleys, with the great channel of the Brahmaputra (literally, the Son of Brahma) flowing down its middle, and an infinite number of tributaries and watercourses pouring into it from the mountains on either side.
The first is an arid desert absolutely barren along part of the coast, between Tacna and Copiapo, but with a coarse scanty vegetation near the Cordilleras along watercourses and on the slopes where moisture from the melting snows above percolates through the sand.
Its surface is a succession of great terraces, facing north and north-east, formed by the denudation of the ancient sandstone plateau which once covered this part of the continent; the terraces are seamed by watercourses, and their valleys are broken by hills and ranges of highlands.
Forest patches are found in the kloofs and seaward sides of the mountains; willows often border the watercourses; heaths and bulbous plants are common in some areas.
Its general appearance is that common to the Doab, a level plain intersected by watercourses and ravines.
The surface is generally low and flat, largely covered with lagoons, watercourses and swamps.
In the south and south-west provinces placer gold mines by the banks of watercourses are worked by Gallas as an industry subsidiary to tending their flocks and fields.
A small part of the northern Colombia, on the lower courses of the Atrato and Magdalena, extending across the country from the Eastern to the Western Cordilleras with a varying width of 100 to 150 m., not including the lower river basins which penetrate much farther inland, also consists of low, alluvial plains, partly covered with swamps and intricate watercourses, densely overgrown with vegetation, but in places admirably adapted to different kinds of tropical agriculture.
In practice it is usual in chalk formations to imitate artificially the action of such underground watercourses, by driving from the well small tunnels, or " adits " as they are called, below the water-level, to intercept fissures and water-bearing beds, and thus to extend the collecting area.