Part 4 (1/2)
Westward beyond the limits of the sketch map, up the Hw.a.n.g ho valley, there is a reach of 125 miles of irrigated lands about Ninghaifu, and others still farther west, at Lanchowfu and at Suchow where the river has attained an elevation of 5,000 feet, in Kansu province; and there is still to be named the great Canton delta region. A conservative estimate would place the miles of ca.n.a.ls and leveed rivers in China, Korea and j.a.pan equal to eight times the number represented in Fig. 52. Fully 200,000 miles in all. Forty ca.n.a.ls across the United States from east to west and sixty from north to south would not equal, in number of miles those in these three countries today. Indeed, it is probable that this estimate is not too large for China alone.
As adjuncts to these vast ca.n.a.lization works there have been enormous amounts of embankment, dike and levee construction. More than three hundred miles of sea wall alone exist in the area covered by the sketch map, Fig. 52. The east bank of the Grand Ca.n.a.l, between Yangchow and Hwaianfu, is itself a great levee, holding back the waters to the west above the eastern plain, diverting them south, into the Yangtse kiang. But it is also provided with spillways for use in times of excessive flood, permitting waters to discharge eastward. Such excess waters however are controlled by another dike with ca.n.a.l along its west side, some forty miles to the east, impounding the water in a series of large lakes until it may gradually drain away. This area is seen in Fig. 53, north of the Yangtse river.
Along the banks of the Yangtse, and for many miles along the Hw.a.n.g ho, great levees have been built, some-times in reinforcing series of two or three at different distances back from the channel where the stream bed is above the adjacent country, in order to prevent widespread disaster and to limit the inundated areas in times of unusual flood. In the province of Hupeh, where the Han river flows through two hundred miles of low country, this stream is diked on both sides throughout the whole distance, and in a portion of its course the height of the levees reaches thirty feet or more. Again, in the Canton delta region there are other hundreds of miles of sea wall and dikes, so that the aggregate mileage of this type of construction works in the Empire can only be measured in thousands of miles.
In addition to the ca.n.a.l and levee construction works there are numerous impounding reservoirs which are brought into requisition to control overflow waters from the great streams. Some of these reservoirs, like Tungting lake in Hupeh and Poyang in Hunan, have areas of 2,000 and 1,800 square miles respectively and during the heaviest rainy seasons each may rise through twenty to thirty feet, Then there are other large and small lakes in the coastal plain giving an aggregate reservoir area exceeding 13,000 square miles, all of which are brought into service in controlling flood waters, all of which are steadily filling with the sediments brought from the far away uncultivable mountain slopes and which are ultimately destined to become rich alluvial plains, doubtless to be ca.n.a.lized in the manner we have seen.
There is still another phase of these vast construction works which has been of the greatest moment in increasing the maintenance capacity of the Empire,--the wresting from the flood waters of the enormous volumes of silt which they carry, depositing it over the flooded areas, in the ca.n.a.ls and along the sh.o.r.es in such manner as to add to the habitable and cultivable land. Reference has been made to the rapid growth of Chungming island in the mouth of the Yangtse kiang, and the million people now finding homes on the 270 square miles of newly made land which now has its ca.n.a.ls, as may be seen in the upper margin of Fig. 52. The city of Shanghai, as its name signifies, stood originally on the seash.o.r.e, which has now grown twenty miles to the northward and to the eastward. In 220 B. C. the town of Putai in Shantung stood one-third of a mile from the sea, but in 1730 it was forty-seven miles inland, and is forty-eight miles from the sh.o.r.e today.
Sienshuiku, on the Pei ho, stood upon the seash.o.r.e in 500 A. D. We pa.s.sed the city, on our way to Tientsin, eighteen miles inland. The dotted line laid in from the coast of the Gulf of Chihli in Fig. 53 marks one historic sh.o.r.e line and indicates a general growth of land eighteen miles to seaward.
Besides these actual extensions of the sh.o.r.e lines the centuries of flooding of lakes and low lying lands has so filled many depressions as to convert large areas of swamp into cultivated fields. Not only this, but the spreading of ca.n.a.l mud broadcast over the encircled fields has had two very important effects,--namely, raising the level of the low lying fields, giving them better drainage and so better physical condition, and adding new plant food in the form of virgin soil of the richest type, thus contributing to the maintenance of soil fertility, high maintenance capacity and permanent agriculture through all the centuries.
These operations of maintenance and improvement had a very early inception; they appear to have persisted throughout the recorded history of the Empire and are in vogue today. Ca.n.a.ls of the type ill.u.s.trated in Figs. 51 and 52 have been built between 1886 and 1901, both on the extensions of Chungming island and the newly formed main land to the north, as is shown by comparison of Stieler's atlas, revised in 1886, with the recent German survey.
Earlier than 2255 B. C., more than 4100 years ago, Emperor Yao appointed ”The Great” Yu ”Superintendent of Works” and entrusted him with the work of draining off the waters of disastrous floods and of ca.n.a.lizing the rivers, and he devoted thirteen years to this work.
This great engineer is said to have written several treatises on agriculture and drainage, and was finally called, much against his wishes, to serve as Emperor during the last seven years of his life.
The history of the Hw.a.n.g ho is one of disastrous floods and s.h.i.+ftings of its course, which have occurred many times in the years since before the time of the Great Yu, who perhaps began the works perpetuated today. Between 1300 A. D. and 1852 the Hw.a.n.g ho emptied into the Yellow Sea south of the highlands of Shantung, but in that year, when in unusual flood, it broke through the north levees and finally took its present course, emptying again into the Gulf of Chihli, some three hundred miles further north. Some of these s.h.i.+ftings of course of the Hw.a.n.g ho and of the Yangtse kiang are indicated in dotted lines on the sketch map, Fig. 53, where it may he seen that the Hw.a.n.g ho during 146 years, poured its waters into the sea as far north as Tientsin, through the mouth of the Pei ho, four hundred miles to the northward of its mouth in 1852.
This mighty river is said to carry at low stage, past the city of Tsinan in Shantung, no less than 4,000 cubic yards of water per second, and three times this volume when running at flood. This is water sufficient to inundate thirty-three square miles of level country ten feet deep in twenty-four hours. What must be said of the mental status of a people who for forty centuries have measured their strength against such a t.i.tan racing past their homes above the level of their fields, confined only between walls of their own construction? While they have not always succeeded in controlling the river, they have never failed to try again. In 1877 this river broke its banks, inundating a vast. area, bringing death to a million people. Again, as late as 1898, fifteen hundred villages to the northeast of Tsinan and a much larger area to the southwest of the same city were devastated by it, and it is such events as these which have won for the river the names ”China's Sorrow,” ”The Ungovernable” and ”The Scourge of the Sons of Han.”
The building of the Grand Ca.n.a.l appears to have been a comparatively recent event in Chinese history. The middle section, between the Yangtse and Tsingkiangpu, is said to have been constructed about the sixth century B. C.; the southern section, between Chingkiang and Hangchow, during the years 605 to 617 A. D.; but the northern section, from the channel of the Hw.a.n.g ho deserted in 1852, to Tientsin, was not built until the years 1280-1283.
While this ca.n.a.l has been called by the Chinese Yu ho (Imperial river), Yun ho (Transport river) or Yunliang ho (Tribute bearing river) and while it has connected the great rivers coming down from the far interior into a great water-transport system, this feature of construction may have been but a by-product of the great dominating purpose which led to the vast internal improvements in the form of ca.n.a.ls, dikes, levees and impounding reservoirs so widely scattered, so fully developed and so effectively utilized.
Rather the master purpose must have been maintenance for the increasing flood of humanity. And I am willing to grant to the Great Yu, with his finger on the pulse of the nation, the power to project his vision four thousand years into the future of his race and to formulate some of the measures which might he inaugurated to grow with the years and make certain perpetual maintenance for those to follow.
The exhaustion of cultivated fields must always have been the most fundamental, vital and difficult problem of all civilized people and it appears clear that such ca.n.a.lization as is ill.u.s.trated in Figs.
51 and 52 may have been primarily initial steps in the reclamation of delta and overflow lands. At any rate, whether deliberately so planned or not, the ca.n.a.lization of the delta and overflow plains of China has been one of the most fundamental and fruitful measures for the conservation of her national resources that they could have taken, for we are convinced that this oldest nation in the world has thus greatly augmented the extension of its coastal plains, conserving and building out of the waste of erosion wrested from the great streams, hundreds of square miles of the richest and most enduring of soils, and we have little doubt that were a full and accurate account given of human influence upon the changes in this remarkable region during the last four thousand years it would show that these gigantic systems of ca.n.a.lization have been matters of slow, gradual growth, often initiated and always profoundly influenced by the labors of the strong, patient, persevering, thoughtful but ever silent husband-men in their efforts to acquire homes and to maintain the productive power of their fields.
Nothing appears more clear than that the greatest material problem which can engage the best thought of China today is that of perfecting, extending and perpetuating the means for controlling her flood waters, for better draining of her vast areas of low land, and for utilizing the tremendous loads of silt borne by her streams more effectively in fertilizing existing fields and in building and reclaiming new land. With her millions of people needing homes and anxious for work; who have done so much in land building, in reclamation and in the maintenance of soil fertility, the government should give serious thought to the possibility of putting large numbers of them at work, effectively directed by the best engineering skill. It must now be entirely practicable, with engineering skill and mechanical appliances, to put the Hw.a.n.g ho, and other rivers of China subject to overflow, completely under control. With the Hw.a.n.g ho confined to its channel, the adjacent low lands can be better drained by ca.n.a.lization and freed from the acc.u.mulating saline deposits which are rendering them sterile.
Warping may be resorted to during the flood season to raise the level of adjacent low-lying fields, rendering them at the same time more fertile. Where the river is running above the adjacent plains there is no difficulty in drawing off the turbid water by gravity, under controlled conditions, into diked basins, and even in compelling the river to b.u.t.tress its own levees. There is certainly great need and great opportunity for China to make still better and more efficient her already wonderful transportation ca.n.a.ls and those devoted to drainage, irrigation and fertilization.
In the United States, along the same lines, now that we are considering the development of inland waterways, the subject should be surveyed broadly and much careful study may well be given to the works these old people have developed and found serviceable through so many centuries. The Mississippi is annually bearing to the sea nearly 225,000 acre-feet of the most fertile sediment, and between levees along a raised bed through two hundred miles of country subject to inundation. The time is here when there should he undertaken a systematic diversion of a large part of this fertile soil over the swamp areas, building them into well drained, cultivable, fertile fields provided with waterways to serve for drainage, irrigation, fertilization and transportation. These great areas of swamp land may thus be converted into the most productive rice and sugar plantations to be found anywhere in the world, and the area made capable of maintaining many millions of people as long as the Mississippi endures, bearing its burden of fertile sediment.
But the conservation and utilization of the wastes of soil erosion, as applied in the delta plain of China, stupendous as this work has been, is nevertheless small when measured by the savings which accrue from the careful and extensive fitting of fields so largely practiced, which both lessens soil erosion and permits a large amount of soluble and suspended matter in the run-off to be applied to, and retained upon, the fields through their extensive systems of irrigation. Mountainous and hilly as are the lands of j.a.pan, 11,000 square miles of her cultivated fields in the main islands of Honshu, Kyushu and s.h.i.+koku have been carefully graded to water level areas bounded by narrow raised rims upon which sixteen or more inches of run-off water, with its suspended and soluble matters, may be applied, a large part of which is retained on the fields or utilized by the crop, while surface erosion is almost completely prevented.
The ill.u.s.trations, Figs. 11, 12 and 13 show the application of the principle to the larger and more level fields, and in Figs. 151, 152 and 225 may be seen the practice on steep slopes.
If the total area of fields graded practically to a water level in j.a.pan aggregates 11,000 square miles, the total area thus surface fitted in China must be eight or tenfold this amount. Such enormous field erosion as is tolerated at the present time in our southern and south Atlantic states is permitted nowhere in the Far East, so far as we observed, not even where the topography is much steeper.
The tea orchards as we saw them on the steeper slopes, not level-terraced, are often heavily mulched with straw which makes erosion, even by heavy rains impossible, while the treatment retains the rain where it falls, giving the soil opportunity to receive it under the impulse of both capillarity and gravity, and with it the soluble ash ingredients leached from the straw. The straw mulches we saw used in this manner were often six to eight inches deep, thus const.i.tuting a dressing of not less than six tons per acre, carrying 140 pounds of soluble pota.s.sium and 12 pounds of phosphorus. The practice, therefore, gives at once a good fertilizing, the highest conservation and utilization of rainfall, and a complete protection against soil erosion. It is a multum in parvo treatment which characterizes so many of the practices of these people, which have crystallized from twenty centuries of high tension experience.
In the Kiangsu and Chekiang provinces as elsewhere in the densely populated portions of the Far East, we found almost all of the cultivated fields very nearly level or made so by grading. Instances showing the type of this grading in a comparatively level country are seen in Figs. 56 and 57. By this preliminary surface fitting of the fields these people have reduced to the lowest possible limit the waste of soil fertility by erosion and surface leaching. At the same time they are able to retain upon the field, uniformly distributed over it, the largest part of the rainfall practicable, and to compel a much larger proportion of the necessary run off to leave by under-drainage than would be possible otherwise, conveying the plant food developed in the surface soil to the roots of the crops, while they make possible a more complete absorption and retention by the soil of the soluble plant food materials not taken up. This same treatment also furnishes the best possible conditions for the application of water to the fields when supplemental irrigation would be helpful, and for the withdrawal of surplus rainfall by surface drainage, should this be necessary.
Besides this surface fitting of fields there is a wide application of additional methods aiming to conserve both rainfall and soil fertility, one of which is ill.u.s.trated in Fig. 58, showing one end of a collecting reservoir. There were three of these reservoirs in tandem, connected with each other by surface ditches and with an adjoining ca.n.a.l. About the reservoir the level field is seen to be thrown into beds with shallow furrows between the long narrow ridges. The furrows are connected by a head drain around the margin of the reservoir and separated from it by a narrow raised rim. Such a reservoir may be six to ten feet deep but can be completely drained only by pumping or by evaporation during the dry season.
Into such reservoirs the excess surface water is drained where all suspended matter carried from the field collects and is returned, either directly as an application of mud or as material used in composts. In the preparation of composts, pits are dug near the margin of the reservoir, as seen in the ill.u.s.tration, and into them are thrown coa.r.s.e manure and any roughage in the form of stubble or other refuse which may be available, these materials being saturated with the soft mud dipped from the bottom of the reservoir.