The Mississippi Problem To the Editor of the SCIENTIFIC AMERICAN: Why, in the name of common sense, does not some one call attention to the construction of flood channels in cities, due to reclamation of bottom lands, bridge piers, abutments, etc., as a cause of floods by reduction of channel cross-section. Now I have been very glad to see that point, which was discussed considerably in Kansas City, in 1904, taken up in your last issue, but I have one suggestion yet left to offer, viz., is it not true that the river channels have been choked, also, by the greatly increased quantities of soil washed into them from the large areas of plowed ground now found in their drainage areas? Early explorers reported many of our streams as clear, which certainly have not that character now. l'lattsburg Barracks, N. Y. G. W. EDGERLY. The Futility of Reservoirs to Control Floods To the Editor of the SCIENTIFIC AMERICAN : Your idea, that the reservoir system of preventing floods in river valleys would be of but little benefit, is well supported by the recent great flood in Ohio and Indiana. Our river valleys were full of water, from source to mouth of stream, to a greater height than any engineer would propose for dams. This condition prevailed for a period of three or four days. If we consider the high velocity of ilood waters, we can readily see what a small portion of this water could have been held back by reservoirs. The breaking of dams, had they been in existence, would doubtless have added to the destruction of both lives and property, since people would have been less willing to leave their homes. Nor would levees have afforded protection on this occasion. The only way to prevent losses, due to a rain like that of March 24 to 27, is to completely abandon all the creek and river valleys. That we would not think of doing, since so heavy a rainfall may not again occur in several centuries. We have seen the streams in the condition which they must have often been during the glacial epoch. Danville, Indiana. C. A. HARGBAVE. An Advocate of Headwater Control To tlie Editor of the SCIENTIFIC AMERICAN : Articles on the Mississippi will be of peculiar interest this year, and the better control of discharge may be the next great national work. A recent article, interesting and plausible, would tend to claim that Nature was elevating the bed of the river itself, through deposit, and that at the same time man was raising the dykes and the overflowed sediment raising the general level of the submerged land. This does seem to be Nature's process, but unless it had only local effect, it would finally create rapids at the sea, for the level of the sea will not rise to accommodate the raised bed of the river. However, rapids have not appeared to any extent as yet. It would be of interest to know what the engineers say of this theory. Higher, larger, and better dykes would tend to scour the present channels better than ever, but will they accommodate the volume of water that must pass within a limited time? If they will not do so, then they are only moderately useful and will not meet the greatest emergency. The' control of headwaters would certainly have great effect, both on average flow and also on flood. Extra accumulations of water from various sources are at times compelled to pass the lower reaches of the river within a certain number of days, and if they cannot do it overflow is the result; and the trouble is on that stretch of river where the accumulated waters bunch up temporarily, and an improved mouth to the river would not be of assistance just there. It would seem that control of headwaters in conjunction with the ability to heavily sluice out water at certain possible points, when the river at those points reached a certain stage, would be the only remedy, excepting that dykes on a larger scale should be still used at points where proved necessary. Partially to close off certain headwaters in case of heavy rains at all headwaters could not fail to have great effect. To hold certain waters back but a few days would have great effect. Time is the chief item in the whole flood question, and the only water that must be controlled is the excess that passes certain stretches within a certain time. VERITAS. Montreal, Canada. Swamp Drainage and the Floods To the Editor of the SCIENTIFIC AMERICAN : I noticed in your issue of February 15th, an article on the overflow of the Mississippi River a year ago this spring. Now in my opinion you are on the right track only you do not make it strong enough. Now I am building dry land dredges and my business calls me to different parts of the United States, and I have a chance to see what a vast amount of drainage is going on all over the country; wherever there is a chance to drain a lake, a slough, a swamp or low land, it is being done. Many of these heretofore have had no outlets, and where they did have, the outlets were many times obstructed by old logs or beaver dams or other obstructions, and many of them had no outlets at all. The water had to soak away or evaporate, which all contributed to hold back the water. Now this is all changed, or is being changed; so where it used to take two or three months to get the water off it now goes off in two or three days, and when this is being done in a vast stretch of country the most of which empties into one river, its effects must be felt, especially when it has to be narrowed up by levee and has to run in a comparatively narrow channel, where it used to spread out over several States. It is estimated that in the State of Minnesota alone there will be this coming summer 100 dredges at work and these will probably dig 1,000 miles of ditch, a large part of which will empty into the Mississippi, and some of these ditches are small rivers themselves, and this work has been going on for several years, and will be continued for some years to come. And this is but the index of other States. Now this building of the levees along the Mississippi just high enough so that the high water just runs over the top and washes out enough to let the whole country along the Mississippi be flooded, and the next year the levees are raised a few inches higher, is not providing against a flood. This is not even providing for the extra demand which has to be taken care of from the extra ditches. We can hardly comprehend or estimate the immense amount of water that the Mississippi will be called upon to take care of at certain times of the year, when there are heavy rains in some parts of the country and heavy snows in others extending over a vast country reaching from the Itocky Mountains on the west to the Alleghany Mountains on the east, and from Canada on the north to the Gulf of Mexico on the south and draining approximately one million square miles of territory. Now, as it looks to me, the only way is to build the levees that we think are high enough, and then add onto them from 50 to 100 per cent in height, and by that means they may be built high enough to stand any flood that may come. And then, too, we may as well count on adding some more, for sooner or later the United States will be called upon to take care of the extra water being drained into the Red River of the North from all the extra ditching going into it from Minnesota and Dakota, in consequence of which there is bound to be sooner or later high floods along the Red River and the United States will be called upon to settle for damages caused by the extra water that the Red River could not take care of. Tomah, Wis. ?. ?. CROSS. Dams to Control Floods To the Editor of the SCIENTIFIC AMERICAN : A partial remedy for flood conditions as now exist has occurred to me; and as I have not seen it suggested in my reading, I will mention it. The usual plan for controlling the heavy rainfall and ordinary spring freshets implies making large reservoirs, in deep valleys, by great masonry dams. Such a measure costs large sums of money, which, with the physical difficulties, defer or prevent anything being done until repeated catastrophes rouse an overwhelming sentiment in their favor. I have visited much of this country, have observed its contour, and make the following suggestions: Almost every stream has wide shallow valleys bordered by meadow land; what are called bottoms in many places. Generally before these floods, such as prevail to-day through the Middle West, the streams are low, and these valleys are not filled with water. When the heavy rain comes the water rushes down the streams till it reaches some narrow place, and at such points it begins to back up, and temporary dams are made by the accumulation of material brought down by the streams. The increasing pressure of the waters held back often becomes so great as to break through the temporary or artificial dam, and the volume as well as the force of the water sweeps all before it. My suggestion is that low dams be put at many plaoes in the course of streams, which would hold back the waters in shallow valleys, so that the floods would flow away gradually and harmlessly. The fertility of the valleys of the Nile, the Mississippi, and other alluvial streams is due to the deposit on them of the silt carried in rapidly moving water; and such an annual deposit on the flat borders of .streams, which would overflow their banks in times of high water only, would greatly and perpetually enrich them, while the damage would be small compared to the very great damage now done, when the water escapes with a rush and an accumulation of force sufficient to sweep dams, buildings, and bridges before it. I know valleys where at suitable places even an elevated roadway crossing it, with suitable spillways, would spread the flood over wide spaces, to run off harmlessly later. Earth dams with a core of masonry, when not exceeding 10 or 15 feet in height, would cost little, and if put at rather short distances apart, along the course of streams, would curb the violent flow of the water; enrich, the land; and in partially dry regions, like western Kansas and Nebraska, impound water which would be of great value in times of drought. The expense of such low dams, often combined with improved roads, now so much in demand, would be well repaid by the freedom from such disasters as now shock us all, by the increased comfort and convenience of the people along such rivers as now overflow; and by much increased fertility to the bordering valleys. White Plains, N. Y. SAMUEL B. LYON. A Protest Against Amateur Flood-Controllers To the Editor of the SCIENTIFIC AMERICAN : I have watched with mingled feelings of amusement and disgust the lucubrations of amateur meteorologists and hydrographers, as set forth in the New York daily newspapers, with reference to the recent floods in the West. ? observe that you have admitted one of them to your correspondence columns, Mr. C. A. Zander of Littleton, Del., who remarks: I am sorry to note the stand you take in the matter of straightening out a river in your otherwise sane views of flood restrictions." I presume this gentleman is new to the SCIENTIFIC AMERICAN, or he would know that the SCIENTIFIC AMERICAN is always sane, in all particulars. In tlii.i particular item of floods, you made recently the first sane statement I ever saw in print regarding the tiling and ditching and drainage of land, which every farmer gets busy with as soon as he cuts off the forests, as a cause of the sudden flooding of streams. Wise and sapient words, these of Mr. Zander: The problem of the Mississippi is the same as that with a brook, save in magnitude and constant level at outlet. A straightened bed will lower the flood crest, etc. This is at par with the rare and wonderful thoughtfulness of the Secretary of the Interior, who advised the people of Ohio to dig runways for the floods. I have before me a photograph showing the Ohio River at Cincinnati at a stage fully six feet below the recent high record The river reaches from the Kentucky hills, some four hundred feet high, to the foot of the hills on the Ohio side. All that is necessary in order to carry out the Secretary's brilliant plan is to set those hills back, perhaps half a mile, for a distance of some 700 miles--and then dig the runway"! Mr. Zander's idea of the Mississippi is equally comprehensive, brilliant,, and practical. Begin at the mouth, straighten channel any distance, make waterway wide enough and dyke high enough to take flood, with a good margin of safety added. Does this gentleman know that the Mississippi River carries at flood tide enough water to cover his delightful little State more than four feet deep in a single day? Does he know that the Mississippi River drains an area about 700 times the size of the State of Delaware? Did he ever watch tall trees falling into it, one after another, as it carved land off the banks by the township? I see no reason why his blithely propounded formula could not be applied to even greater affairs. For example, a bridge across the Atlantic: Build your piers high enough, above flood tide, connect them with trusses, and lay your tracks. Or a railroad tunnel straight through the earth: Dig a hole deep enough, shore it up safely, provide an elevator to the center and a corresponding one on the other side." No doubt improvements will be made in the control of the Mississippi, as well as in the control of the floods in all parts of the Ohio River watershed; but the work will be best accomplished by people who live there, people who have lived through the floods, and who have some sensible conception of the size of the job. And after all the flood controlling is done, Nature some day will turn loose a heavier rainfall than man had ever seen before, and the flood defenses will operate simply as a means of sudden precipitation of the calamity, when they yield before Nature's power! I have seen the Mississippi River eight miles wide at St. Louis, with a current of nearly six miles an hour, and I protest against the annoying of people who are suffering from the ravages of the flood at this time by nonsense from engineers of the kindergarten stage, whose fields of observation have been spring tides in the Erie Canal or the gaging of some creek whose annual flow would not equal the Mississippi's rate per minute. Furthermore, I have full confidence that the SCIENTIFIC AMERICAN'S outgivings on the general subject of flood control will continue to be not only partly sane, but entirely so. WAI/??? C. TAYLOR, Boston, Mass. Editor The Boot and Hhoe Recorder.
Correspondence - May 3, 1913
This article was originally published with the title "Correspondence" in SA Supplements 75, 1948supp, 397 (May 1913)