waterlogged and useless for crops although such drowned soils are still capable of supporting several types of swamp vegetation. Hygroscopic water exists as an extremely thin film
around each soil particle, somewhat as though each particle were “wrapped in cellophane.” It is often referred to as “unavailable water” because plants cannot obtain it. Capillary water is
the water which moves by capillary action, or attraction, in the same fashion that spilled ink may be drawn into and among the fibers of a blotter. Its ability to move even against the pull
of gravity is significant for, as topsoils dry out, capillary water is drawn to the upper portion of the soil where it supplies the needs of plants. However, if such action is too long
continued, particularly if the water is drawn all the way to the surface, soils become either weakly or strongly saline. This occurs when the water, drawn to the surface, is evaporated
and leaves its minerals behind. If there is insufficient precipitation to wash the minerals, or mineral salts, back down into lower parts of the soil, permanently saline soils are created. If
they are mildly saline, a few mineral salt-tolerant crops may be grown; with high salinity, no crops can grow although a few specially adapted types of natural vegetation halophytes may
be able to exist.
3.3 Some Water Problems
The preceding discussions have shown that man is confronted with many problems as he attempts to use or to protect himself from the earth’s waters. The problems are more
numerous and, some of them, more serious than ever before because man himself has created many of them and has often made those of natural Origin more pressing.
To suppose that the struggle for control of the seas and oceans is over, merely because they are no longer effective defenses against swift ships and supersonic aircraft and
rockets, is to be unrealistic. They are still vitally important sources of food and other products of which many nations are growing increasingly aware.
These are both friend and enemy to man: friend in that they serve so many of his needs; enemy in that they go on rampages of destruction or change their courses and thus
confuse property limits and political boundaries, or become polluted and carry filth and disease.
The problem of high water is acute in densely populated regions, especially where the presence of fertile flood plains and strategic trade and manufacturing foci has lured large
populations not only into the lower areas but to the very edge of the low-water channels. It has been said that the problem is not so much to keep the rivers away from the people as to
keep the people out of the rivers. The magnitude of the problem is partly indicated by the fact that one serious flood on the Tsunami in Aceh may take scores of lives and cause hundreds of
millions of dollars in damage, may drown thousands of persons and cause untold damage to fields and sorely needed crops, not to mention the famine and pestilence which ride hard on
the heels of such a flood. The control of river waters to the point of preventing serious floods is neither easy
nor inexpensive. Normally it requires careful study and artificial controls of entire drainage basins from uppermost tributaries to stream mouths and the costs run into millions of dollars.
Also, it requires the cooperation of many agencies and of the public as a whole. Yet it may be cheaper to pay for proper controls than to pay the bills for flood damage, particularly if man
continues to crowd the rivers. Stream control itself is only part of the price man pays for cutting away the forests, breaking the sod of grasslands, running cultivation furrows up and
down the slope instead of aligning them with the contours, and settling in the natural drainways. Remedies lie in reforestation, regrassing, contour plowing, strip cropping,
construction of large and small dams—in general, in wise land-use policies operating throughout entire drainage areas, including suitable adjustments in the use of areas of flood
hazard.
There is always a certain amount of erosion under perfectly normal conditions, but it is seldom, except in dry regions, that normal erosion causes any widespread difficulties. It is
when natural balances are upset and waters speed unchecked that erosion rises far above normal, and land, soils, and the works of man are then destroyed. It may be possible to
rebuild rather quickly the works of man, whether bridges, highways, or homes, but destroyed soils cannot be replaced for many genezations and, in most instances, they are gone for all
time. When one realizes that soil is the most valuable of all the resources of the earth—coal, iron ore, and others not excepted—it is startling to learn that we in the United States already
have allowed erosion to steal about one third of our best topsoil. That, to use a very trite expression, “is something to think about.” It is also a situation to do something about.
In regions where water is naturally scarce or in humid areas where demands on surface and ground waters are especially heavy, there arise many conflicts over rights to
water. The majority of such conflicts revolve around stream water. in the “old days,” the disputes were normally settled by force; today they are settled in court and in terms of laws
and procedures which have become very complicated. It is not unusual for litigation of a given dispute to continue for several years, or even for decades. Problems of water rights are
particularly complicated in connection with streams which flow through two or more states or in more than one country.
Countless streams formerly clean and attractive have already been polluted by man. This results not merely from increased loads of sediment coming from man-induced erosion
of the land, but also from dumping sewage, trash, and industrial wastes into the nearest convenient stream. The problem has become so serious and widespread that laws to prevent
pollution of streams have been adopted in many regions. Such laws are, however, too few in number, and they are honored more in the breach than in the practice. Until industrial wastes
and domestic sewage are properly treated, far too many of our streams will continue to resemble moving cesspools.
Some of the dangers already noted apply to waters within the earth as well as to those on the surface. The destruction of natural vegetation cover, abnormal erosion, and rapid
water loss affect the amount and character of ground water as well as the behavior and nature of streams. When surface waters are not conserved, it is only a short time before the water
table is lowered and springs and wells diminish or dry up entirely. Indiscriminate pumping also may drain the ground water reserves and lower the water table to the point where
pumping costs are prohibitive. This can happen even in humid areas.
4. CONCLUSION AND SUGGESTION
