The Floods of the Mississippi Valley
“The perfect control of the Mississippi system of waters is perhaps the greatest engineering problem that our race has ever had to attack.”
As man extends his control over the surface of this continent, he finds that perfect mastery of it is not easily attained. He deals here with a ruder mother earth than that which environed him in the Old World; frost, flood, and drought, the three dangers of climates in high latitudes, are all more serious evils on this continent than he found them in the cradle lands of his race. In Europe and Western Asia the land is divided into physical kingdoms, or subdivided into principalities, by mountains or arms of the seas. The forces of nature are tamed by the division; floods and famines find barriers set against them, and the worst natural accidents are local in their action. In America there is far more unity in the destiny of the land; blessings and curses have a wider, freer range.
Let us notice at the outset that there are two different North Americas: the one the geographical continent, such as is delineated in maps, and the other the continent that can have any profitable relations to man, — which can support him by its soil, or help him by its mineral resources.
As far as man is concerned, all the areas of North America that drain into the Arctic Sea, and nearly all that drain into Hudson’s Bay, may be regarded as not existing. It would be well if they could be taken below the sea, for there is no human promise to them, and if they were away the rest would be more favored in its climate. We must make a similar subtraction for all the region between the meridian of Omaha and that of Sacramento and north of Mexico. Here and there, in this area, are patches of land where men may win bread; but of it all, not over the tenth part will ever see a harvest.
South of the United States, in Mexico and Central America, nature is less niggardly than in the Northern Cordilleran section, and there is a chance for patches of fertility high enough in the mountains to escape the evils of the tropics; but, as a whole, we may say that man has already entered on all his inheritance on this continent.
In its economic aspect, this continent divides itself into four main regions, which, though not very distinct from each other, are peculiar enough to deserve separate names. They are the Atlantic coast belt, including the borders of the Mexican Gulf; the Laurentian basin; the Pacific coast; and, between these, the great basin of the Mississippi. Of these areas, the great central river basin is the chief; we may indeed call it the trunk and viscera of the continent’s body, the other parts being only the outlying limbs. Measured in terms of men yet to live on this land, the Mississippi area is many times greater than all the rest of the continent put together. Measured by its future acres of grain, or the future tonnage of minerals, the two prime motors of our economic life, we find that it holds the material wealth on which must rest the burden of the life in the twentieth, and we know not how many more centuries.
As the largest element of our national heritage, this great valley may well receive the especial consideration of the state.
The Mississippi Valley differs in many ways from any other river valley with which our race has had to deal. In the first place, it is much larger than any of the valleys of Europe; it has a greater share of alluvial lands along its several streams, and a more extensive delta at its mouth, than any Old World rivers. The process of occupation by man, and the change in the conditions which this occupation brings about, have taken place with great rapidity, without allowing any time for the readjustment of the physical conditions which the use of a region by civilized men compels.
When our race came to occupy the Mississippi Valley, its conditions had already been modified by the action of his Indian predecessors to a considerable degree. Nearly all the region west of the Mississippi, and a large portion of that to the north and west of the Ohio, where now lie the States of Indiana, Illinois, and Wisconsin, were destitute of forests. In part, this absence of woods was due to the original influence of climate; but in larger degree it was owing to the Indian habit of burning the herbage, to foster the growth of the fresh grasses which were so advantageous to the buffalo and other large game. East of the Mississippi, it seems pretty clear that this process of deforesting was principally, if not entirely, due to this peculiar forest and prairie burning habit of our predecessors on this continent.
Thus the whites came to this valley at a time when it was in good part unwooded; when the great unbroken forests were, in the main, limited to the eastern or Ohio district of the valley. This district was harder to deforest than that west of the Mississippi, on account of its greater rainfall. The eastern side of the Mississippi has at least twice the rainfall that comes to the western side of the valley; so its wet forests were hard to burn. To this, we owe the fact that the Indians had not carried the treeless belt up to the very foot of the Alleghanies.1 But what the savages could not do with fire, their successors, more skillful despoilers of the earth, have set about with the axe. A large part of the forest coating of the Ohio Valley has disappeared, and what remains is marked all over by the hand of man.
The first and most important result of this invasion of the forests by civilization is that the rain-water flows more rapidly into the streams, and thence to the sea, than it did before. We easily perceive how this is brought about. In the old virgin forests, whose wildnesses are known to few, the water had a long and slow journey to the main streams. There was commonly a foot or more of vegetable mould, porous as a sponge, and capable of retaining a rainfall of several inches, which it yielded slowly to the streams. This was overlaid in every direction by fallen trees, whose mouldering frames made little dams across every depression, from which the water would slowly filter down the drainage slopes. In the torrential rains that flooded the surface of the wood, the action of the flowing water heaped the decayed débris in every channel, and served to bar its path to the main streams. When the flood had found its way to the open brooks, it encountered the system of beaver dams, which once existed in thousands along all the lesser streams. These wonderful structures have long since passed away; but when the whites first came to this country, every stream less in size than the smaller rivers was dammed here and there by these barriers, so admirably fitted for retaining the waters in the flood times. It was the habit of these primitive hydraulic engineers to abandon their dams whenever they had cleared away their favorite species of trees that grew near them, and to build others; so that a colony of beavers would in a few years construct several dams beside the one they occupied at any particular time. Each of these barriers held the waters imperfectly, serving only to hinder the flood in its swift course; no one dam would hold more than a few acres of water; but, with every little “branch” full of them, the aggregate restraining effect on the current was very great indeed. The floating ice and drift-wood would catch on the barrier of the dam, and so increase its effect in holding back the waters.
There are no data for estimating the relative length of time it required for the floods to escape while these conditions prevailed, compared with the rate of speed that now marks these down-going waters. But it is pretty clear that it must have required at least twice, perhaps thrice, the time for a flood to pour its waters by a particular point on the Ohio one hundred and fifty years ago that it does at present. Let us consider how man’s interference has changed the behavior of these floods. In the first place, the larger part of the forests have utterly disappeared. Instead of the spongy mass of the forest bed that never could be entirely closed by frost, and of the sheltering woods that fenced the snow from the sun and from warm winds, we now have more than half the valley, with bare fields, compacted by tillage, open to sun and to the south wind, freezing to the hardness of stone, and from which the rains of the late winter flow away as speedily as they do from the house roofs.
Besides this, all the heaver-dammed, timber-obstructed streams are cleared out, in order that the lumberman may “run” his logs from the remnants of forests among the hills. All the alluvial lands along the streams are turned into open fields, so that the overflowing water has no longer to creep through a tangle of vegetation, as soon as it escapes from the channel, but may move swiftly, however wide its stream. If now, after a time of frost, there comes a general rain that exceeds two or three inches in total fall, the water from the most of the valleys is swiftly precipitated into the main ways, and it all hurries at the average rate of six or more miles an hour from the place where it falls to the earth to the great rivers. These main rivers speedily escape from their banks, and flood the fields and towns throughout the alluvial plains, carrying destruction all the way to the sea. For a time, the increasing volume of the flood waters that each year has brought has managed to make some compensation for itself. The main channels have been widened by cutting away the alluvial plain on either side. In this fashion the flood water way of the Ohio has widened by about one fifth since the settlement of the country began. But now, when many cities have grown on its banks, and the alluvial lands have come to be highly valued, means have been taken to keep the stream as far as possible within its bounds, and even to recover some part of its recent gains on its shores. So the waters are compelled to mount in height, and they rush onward in a swift tide that requires several days to pass any given point. As this flood, reinforced by every tributary, goes onward, it lengthens, but becomes less deep, and takes more hours to pass by. Thus a flood that will be dangerously high for only two days in the upper Ohio will be a week above the danger line on the Mississippi. It is impossible to estimate the loss by such a flood as that of February, 1883, on the Ohio. We can only enumerate the classes of damage done. First, we have the loss from the sweeping away of the soil. As I stood, during the time of the February flood, on a bridge over the Ohio at Cincinnati, looking at the roaring mass of waters, full of wreckage of fences, bridges, houses, and barns, that gathered in quivering, changing heaps against each of the massive piers, I felt that the immediate loss of these temporary structures was less important than the wastage of soil that the stream was bearing away to the sea. Each minute the fertility of a farm went by in the yellow tide. In this floating soil, the slow winning of many geological periods, the possibilities of food for millions to come slips away unseen in the turbid waters. This is the greatest and least replaceable of the losses. Next comes the immediate loss of structures of all kinds; then the interruption to business in the alluvial tracts that take the burden of the flood; last, and most grievous, but hardest to estimate in money, the epidemics that follow in the train of these floods. The great overflows of 1847 and 1852, which this flood of February, 1883, far exceeded, were followed, in the succeeding warm seasons, by calamitous outbreaks of cholera and related diseases. The lesser inundations of intervening years have apparently left their several marks on the death-rate of the valley. The flood of February of this year is estimated to have occasioned a loss of a million and a half dollars at Cincinnati alone. It is doubtful if the direct loss in the Mississippi Valley will be less than fifty million dollars; and if pestilence should come in its train, the money damage may go far beyond this amount.
Bad as this is at the moment, the prospect for the future is yet more discouraging. The remaining forests of the Ohio Valley, which still cover something over one third of its surface, and serve to modify the floods, lie principally in the mountain districts about its head waters, — the head streams of the Tennessee, Cumberland, Kentucky, Licking, Sandy, Kanawba, MonongaheIa, etc. These forests clothe steep hillsides, whence the infinitely ramifying streams fall rapidly to the main rivers. The heaviest rainfall of the valley is in this district. As yet the lumberman has left much of this country unchanged; the flood water has there something of the slow escape that once marked its overflow in all the lower regions as well. Now, however, the changes arising from settlement is invading these valleys; the axe is stripping their hill-sides, turning them into bare roofs, from which soil and water flow away in swift yellow torrents. The streams are losing the old barriers of fallen trees arid the tangle of lodged drift-wood, that moderated the speed of the current even after the beaver dams had disappeared. When these mountain ridges have been thoroughly subjugated, a process that will be complete within half a century, the disastrous power of the flood will be greatly enhanced; for this region has the largest rainfall of any part of the valley, and when stripped of its forests will, on account of its steepness of surface, send its tide of water with greater speed to the low countries than those regions which now give the worst floods. The question comes before us, Is there any remedy for these inundations, or must they be submitted to with the necessary patience with which we endure cold and droughts? For the lower portions of the Mississippi, that vast alluvial plain, richer than the low-lands of Holland or of the Nilotic delta, a remedy, or at least a satisfactory palliative, may be found in the system of diking and of side outlets, which have been so well proven in many other lands for thousands of years. As soon as the nation comes to a full sense of its duty by its inheritance, this part of the evil will certainly be dealt with. On the upper waters, the greater height of the flood line in relation to the alluvial lands makes the problem much more difficult. Dikes twenty feet high would often be needed to make a safe barrier to the stream. The construction and maintenance of such works, though not beyond the powers of engineering, would be a work of impracticable magnitude. Moreover, the inconvenience of such barriers would be very great. In the numerous cities that have grown and are to grow along these streams, such dikes would prove more inconvenient than the walls of mediæval burgs. Additional outlets for the waters are not possible here, as they are in the delta region of the main river.
The only conceivable resources may be found in the possible means of retaining the flood waters in the uplands, so that they may he more slowly discharged into the greater tributaries. Speaking generally, we may say that a flood that will be disastrous if it passes a given point in six days will not rise out of the usual water way if it could be made to take eight days in its passage. Is it possible to retain in the uplands enough of the flood waters of the Ohio to prolong the period of its passage, say at Cincinnati, by as much as two or three days? This problem has never, to my knowledge, received the discussion which it merits. Some years ago, a Mr. Charles Ellet, Jr., a distinguished engineer, proposed to construct a large dam on the upper Kanawha, designed to retain enough water for the replenishment of the stream in times when the water becomes too shallow for the uses of navigation. This is the only considerable inquiry into the problem of water storage in the Ohio basin that is known to me.
Some years ago, while acting as state geologist and surveyor of Kentucky, I looked into the old natural function of the beaver dams; and from them I obtained the idea that it might be possible to make temporary reservoirs, which should be flooded for only a few days in the year, and which would serve to retain enough water to lower the flood height of the main stream by a few feet. I examined a few specimen areas in that State, to determine the possible size and to get approximate estimates of the cost of such dams. My data were very imperfect: but it seemed possible, with about one thousand reservoirs, averaging fifty acres in surface, with a mean depth of ten feet, to hold back the dangerous, or at least the most destructive, part of the flood tide that passes Cincinnati in one day; and that three thousand dams of this area, or a total surface of somewhat over one hundred thousand acres of water reservoirs, having a mean depth of ten feet, would be required to lower the water at Cincinnati below the level of great destruction during such a flood as that of February last. The cost of such dams would be great, but it seemed to me likely that it would not exceed an average of somewhere near ten thousand dollars each, or a total of about thirty million dollars for the completed work. There would probably be no serious difficulty in insuring the automatic action of these dams, so that supervision would not be expensive. The structures being of a cheap character, the annual repairs should not be a serious charge. The occupation of the land by the waters would be only temporary; it need not endure beyond the period of winter; by the middle of March the gates of the dams could be thrown wide open to the passage of the waters, and the land given to the plow. The effect of this overflowing, provided it did not extend later into the season than the first of April, would be advantageous to the land. It would receive each winter a refreshment from the silt deposited upon it, so that, in place of being harmed, it would be helped by the flooding.
If this system should, on careful inquiry, be found practicable, it would be easy, with slight modifications, to make it serve the purpose of maintaining a sufficient depth of water for navigation during the summer season. It was once supposed that the extension of railways would destroy the usefulness of these water ways, but experience has shown that the navigation of the Ohio grows greater each year. The carriage of freight now far exceeds the traffic on any railway in the country. Through its channels the coal supply of the region adjacent to the Mississippi naturally finds its way from the vast coal fields of the Appalachian Mountains. An immense and rapidly growing freight of iron, salt, and lumber passes along its ways to market, at a cost of less than half what would be required for its carriage on any railway. Owing to the widening of the channel and to the loss of water-storing power in the country, the river is essentially unfit for this work for several months each year; the water being too shallow for any but the smallest steamers. By making a part of these dams storeplaces for the waters of the later spring season, and releasing this water in the time of droughts, as proposed by Mr. Ellet, a better depth of stream could be maintained during the period of short rainfall. I believe that the profit to the country derived from this benefit alone would go far to compensate for the cost of the whole project, if it did not in itself entirely warrant it. This plan is not purely speculative, for something of this sort has been accomplished in certain European rivers, where a system of temporary rises in the water of navigable streams, little freshets, coming at short intervals, is produced by means of such storage reservoirs.
It should not be supposed that this project of flood retention is sufficiently matured to warrant its immediate adoption. It may be claimed, however, as it is the only possible solution of a very grave problem, that it is fairly worth the thorough inquiry which only a careful and widely extended survey could give it.
We may notice that any scheme which would serve to lower the flood line at Cincinnati by as much as ten feet would diminish the freshet level on the lower Mississippi, below Cairo, by a proportionate amount, or probably by something like two or three feet of altitude. This would make the problem of protecting the lands of the lower Mississippi, the most fertile lands of America, a region that has a food-giving power as great as half the State of Iowa, much easier than it now appears to be. The essential difficulty of the lower Mississippi floods lies in the upper three feet of their rise. If that much could be taken away, the problem would be far simpler than it now is.
We may also notice that this project is consistent with the plan of improving the navigation of the smaller tributaries of the Mississippi system, which has already received some attention from the federal government. To give good access to those stores of mineral wealth in the Appalachians, which the proper development of the whole valley demands, will require the improvement, by locks and dams, of these streams in the admirable fashion in operation in France and parts of Germany, where every stream that can in any way be made an outlet for trade has been brought into use. Such a system of water ways will require an extensive series of pools for water storage, which would naturally be a part of the proposed reservoirs for the retention of the flood waters. Indeed, when this system of lockage arid damming is completed, the works necessary for the retention of floods and for the maintenance of a summer supply in the main river would incidentally be, in part, accomplished. So that all the necessities of improvement in this river system are parts of the same great task.
Somewhat apart from these lines of profit, but still worthy of notice, we may note the probable advantages to the climate and tillage of the country derived from the longer retention of the waters in the lands. Although a certain proportion of these reservoirs would be used only for the temporary storage of the water, it is likely that a large part of them would be used to retain their water to the times of drought. The presence of these reservoirs in the region could hardly fail to have some effect upon the climate in dry seasons through the evaporation of their water.
Just as the forests engender thunderstorms from the great volume of water they yield to the air in hot seasons, so a multiplicity of small lakes would act to supply the material for local rains. There is yet another advantage to be derived from the detained flood waters: they could be used for the purposes of irrigation, an art that can be profitably applied to most of the fields of the Mississippi Valley that border on the streams. The trouble is that, during the time of drought, these streams yield so little water that they could not be made to serve for irrigation. The waters held back by dams from the flood season could be made to serve this need in times of heat and drought, and would doubtless, in time, be availed of to the great benefit of the agriculture of the district.
It is not to be denied that the perfect control of the Mississippi system of waters is perhaps the greatest engineering problem that our race has ever had to attack. The great rivers of China are the only streams of the thickly peopled parts of the world that present anything like the difficulties that we have to encounter here. The larger streams of Europe, the Rhine, the Danube, the Po, and the Rhone, all have great natural storage reservoirs on their upper waters, that limit the action of the mountain-horn floods, and tend to equalize the flow of their waters. No such reservoirs exist on the tributaries of the Ohio and the Missouri, or any other of the Mississippi affluents, except on the head waters of the stream which is incorrectly termed the upper Mississippi.
I have limited these considerations to the valley of the Ohio, because the problem is more serious in that valley than in those of the other great embranchments of the Mississippi. Its greater rainfall, the denser population, bringing more cities upon its banks, makes the needs more imminent there than elsewhere. In the Missouri Valley there are few forests to clear away, the rainfall is much less, and population has not become great enough for its banks to be occupied with great cities; still the problem there is only less serious than on the Ohio. Very destructive floods ravage its fertile alluvial lands; and if the destruction is less wide-spread than on the Ohio, it is in part because there is, as yet, less to destroy. Moreover, the Missouri Valley is a region where the incidental profit which would arise from the storage of water would be greater than in the more eastern valley of the Ohio, for the reason that the summer droughts are more serious, the river then shrinks to a lesser stream, and the need of irrigation water is more serious. Apart from the effect in mitigating floods, the storage of water in the uplands of this woody region would be very profitable to all its interests. Indeed, this system is demanded in all the great valleys that enter the Mississippi from the west.
Nature, in giving us the finest river valley for the benefit of our race that the world affords, has given with it a burden of labor worthy of our government. Unhappily, at the present time, the evils of our system of national appropriations for internal improvement have brought a certain odium upon all schemes for the betterment of our water ways. There is an unreasoning disposition among our people unreflectingly to condemn all such projects.
This state of the public mind will, it is to be hoped, prove transitory. The problem of the Mississippi water system is a national problem. It will soon become so urgent that it must be treated in a national way. If the federal government, led by a sectional feeling that is in striking contrast with the state of the public mind a decade ago, refuses to undertake the matter, then it will necessarily be undertaken by some form of association among the States that are most immediately concerned therein. It needs no Daniel come to judgment to show that such an associated action of States in a matter of continuous governmental work would be full of the gravest political dangers. It would be a federation within the nation for mutual protection against a danger that the general government had failed to repel. It could not fail to weaken the bond of common interest, the source of common obligation, which we gave a generation of labor and of life to affirm. Once let it be established in the public mind that the vital interests of each section must be cared for by associations of the States that are immediately concerned therein, and the idea of a great all-sustaining commonwealth will be fatally weakened. Such a sundering of the moral union of the people would pave the way to, if it did not in itself warrant, a political disintegration of the nation. It seems to me certain that no such policy of blind neglect can ever meet with continued approval in this country. If the governments of Europe, despite their burden of war, and of constant preparation for war, can care for the condition of their water ways, if Great Britain can secure to the people of India the advantages of storage reservoirs to meet the needs of drought-times, our own government, free from all burden of armaments, and soon to be free from the load of national debt, will surely prove that it is willing to do all that is possible to meet such exigencies. Against this tide of necessity political prejudices and sectional jealousies can make no permanent headway. Practical modern governments exist for such duties, and will be properly judged by the efficiency with which they accomplish them. Just as ancient régimes maintained themselves by the power with which they resisted armies, keeping out the Goth, or the Turk, or other foe, so the governments of the practical age we are entering will stand or fall by their power to combat the elemental enemies, pestilence, flood, and famine, or what else of ill to which man once tamely submitted.
- I am aware that this view of the origin of the prairies in the Ohio Valley is not generally accepted, and cannot here enter on the proof of it; but I may say that, in my opinion, it rests on abundant evidence. ↩