The New International Encyclopædia/Mississippi River
MISSISSIPPI RIVER (Algonquin Missi Sepe, great river; literally, father of waters). The principal river of the North American continent; counting as a part of it the longest branch of the drainage system, the Missouri, which far overtops the central stem, it is the longest river in the world. Its course is entirely within the United States. Popularly, the name is applied to the main north and south stem of the system, which rises in the highlands of Minnesota, in Elk Lake, just south of Lake Itasca, in latitude 47° 10′ N., longitude 95° 10′ W. Its sources are 1462 feet above the Gulf of Mexico, into which it empties. Its general course is southerly, with numerous windings, giving it a length of about 2500 miles to its mouth in latitude 29° N., longitude 80° 15′ W. Following up the Missouri branch, and the Jefferson to its head in southwestern Montana, the total length of the Mississippi-Missouri, from its source to the Gulf of Mexico, is fully 4200 miles. The Mississippi and its branches drain the entire western slope of the Appalachian, and nearly the whole eastern slope of the Rocky Mountain system within the United States, its drainage basin covers an area of about 1,257,000 square miles, or over two-fifths of the total area of the United States, exclusive of Alaska. It is navigable to the Falls of Saint Anthony at Minneapolis, 2161 miles, and by smaller boats above the falls. Its tributaries large enough to be mapped on a chart of comparatively small scale number 240, among which are 45 at present navigable. The most important of its tributaries navigable by large or small boats are the Missouri, navigable to the Great Falls in Montana, 2300 miles; the Arkansas, navigable to Wichita, Kan.; the Red River, navigable to Gainesville, Tex.; the Ohio, navigable to Pittsburg, Pa., 963 miles. The total navigable length of the Mississippi and its tributaries is over 14,000 miles following the river windings, and 9000 miles measured in straight lines. The river forms a portion of the boundaries of ten States, having the southern part of Minnesota, and the States of Iowa, Missouri, Arkansas, and most of Louisiana on the west bank; and Wisconsin, Illinois, Kentucky, Tennessee, and Mississippi on the east. Twenty-one States and Territories are intersected by the navigable waters of this great system. The chief cities situated on its banks are New Orleans, Natchez, Vicksburg, Memphis, Cairo, Saint Louis, Quincy, Burlington, Rock Island, Davenport, Dubuque, Saint Paul, and Minneapolis.
Description of Natural Features. The sources of the river are in Lakes Elk, Itasca, Bemidji, Cass, Winnibigashish, Fishing, Leech, and Mud, lying among hills of drift and boulders, in the midst of pine forests and marshes. From Lake Itasca to Bemidji the stream is about 12 feet wide and 2 feet deep. It issues from the latter 120 feet wide, flowing to Cass Lake, which it leaves with a width of 172 feet, contracting and deepening below as it flows through marshes till it comes to a junction with Leech River, where it has rapids of 20 feet, called the Falls of Pokegama, 270 miles from the source. To this point small steamers navigate. The total descent to this point is 324 feet. Thence to the mouth of Crow Wing River, 247 miles, the river falls about one foot per mile. It is narrow through this distance and winds through oak and maple forests, marshes, and sandy hills, where the formation of rock is overlaid with the gravel and boulders of the drift period. Below, the river passes through a prairie country down to Elk River, and is stained slightly with the brownish color given by piney and marshy vegetation; 133 miles below the Crow Wing are the Sauk Rapids, one mile long, where Potsdam sandstone first outcrops on its banks and extends from that point down to Dubuque and Rock Island. The Falls of Saint Anthony at Minneapolis are 18 feet high, with a breadth of 1200. Up to this point the river is navigable for commercial purposes, though practically Saint Paul is the head of navigation. The river widens below Saint Paul into what is called Lake Pepin, studded with islands. From the Falls of Saint Anthony to the junction with the Missouri, near Saint Louis, the river flows through a valley of great beauty and uniform fertility. Cliffs and rocky bluffs, from 200 to 300 feet high, give a picturesque character to that part of the valley below Rock Island, where it strikes the Carboniferous strata, the geological formation of the valley, to about 100 miles below the Missouri. At Rock Island, 381 miles below Minneapolis, there is a small fall, but the river is navigable between the right bank and the island 3 miles long with the aid of a canal constructed by the Government. Similar improvements have been made at the rapids near the mouth of the Des Moines River, so that the navigation of the Upper Mississippi is uninterrupted below the Falls of Saint Anthony. The surging, muddy, eddying waters of the Missouri, for a long distance, flow side by side with the clearer waters of the Mississippi, joining but not blending, till thrown together by many a crook and turn and eddy between the bluffs of the great valley. Before the Ohio River joins them, the union is complete; but the waters remain turbid to their junction with the sea, and, where joined by the currents of the Arkansas and Red rivers, take a more reddish color.
From the Falls of Saint Anthony downward level flood plains or bottom lands begin to appear adjacent to the river on one or both sides, becoming gradually lower as we proceed down the stream. This vast flood plain lies from 300 to 500 feet below the surface of the bordering uplands. Above Cape Girardeau, Mo., 30 miles above the mouth of the Ohio, these flood plains are still clearly above the level of the river, though they are sometimes subject to inundations. These bottom lands, both high and low, are of the highest order of fertility, those farthest north being used for cereals. Some of the largest have been reclaimed from liability to overflow by dikes across the water-channels by which they were inundated. Say Island, in Pike County, Ill., so reclaimed, is 40 miles in length. The American Bottom extends from the mouth of the Missouri 90 miles down the river on the east side with an average breadth of 6 miles. Below Cape Girardeau, on the west side, the whole country down to the Gulf is bottom land for an average width of 50 miles. But throughout this stretch, from Cairo, at the mouth of the Ohio, to the Gulf, the river flows in a channel on the summit of a low ridge, the land sloping gradually away from the banks on either side, so that the whole or the greater part of the bottom lands lie below the level of the river surface. Every watercourse in this bottom land, whether stream or bayou, flows in a similar channel, on a ridge created by its own deposits. The slopes of these ridges are the cultivable lands of this region. The intervening areas are mainly marshy, and in Louisiana are entirely marsh, rising but a few feet above the Gulf level. From Cairo, Ill., as far south as Memphis, Tenn., the river impinges on the east bank, leaving its bottom land on the west side. Thence southward as far as Natchez, Miss., there is a broad extent of bottom land on the east side, known as the Yazoo Bottoms, which are intersected by many bayous, the chief of which is the Yazoo. On the west side is also a wide bottom land, which extends almost continuously to the Gulf of Mexico, widening southward. On the east side the river impinges against the bluffs for some distance south of Natchez, but below the boundary between Mississippi and Louisiana bottom land appears again on this side of the river and rapidly widens toward the Gulf. The entire valley of the lower section of the river is margined by bayous or arms, which leave the main stream to rejoin it farther down, and considerable parts of Louisiana, Mississippi, and Arkansas are intersected by them.
Another characteristic feature of the adjacent bottom lands are the countless crescent-shaped lakes, oxbows, as they are called, which line the river on either side, but are partly or wholly separated from it. These are formed by cut-offs. The river flows in great curves, which constantly tend to increase in diameter. Thus they encroach on one another, and finally at flood-time, when the impact of the current becomes strongest, cut through the narrow neck separating adjacent curves, thus shortening the course, and leaving the loop as a crescent-shaped lake.
Below the mouth of Red River, the Mississippi divides into branches, the Atchafalaya, Plaquemine, and Lafourche bayous being examples of such distributaries. In the lowlands near its mouth below New Orleans it divides still further, entering the Gulf by means of several passages known as passes, the principal of which are the Southwest and South Passes and the Pass à l'Outre. At the mouth of each of these passes, except the South Pass, where jetties have been built to prevent it, is a bar formed by the deposit of silt from the river on meeting the quiet waters of the Gulf. The quantity of sediment brought down by the river is enormous, being below the Missouri .0035 of the volume of water, which latter amounts to 145 cubic miles per annum. The area of the delta of the river is estimated at over 12,000 square miles. It is everywhere threaded with interlacing bayous and navigable channels, placing every cultivable acre of its lands near to steamboat navigation, one-tenth of the land being estimated as taken up by such water surfaces or channels. The timber in the delta region is mostly sycamore, cypress, and oak—the sycamore margining the streams, the cypress occupying the swamps, and the oaks the lands not liable to frequent inundation.
The climate of the Mississippi Valley ranges from semi-arctic to semi-tropical. At the Falls of Saint Anthony, and above, spirit thermometers must be employed to register the extreme low temperature in winter, which often touches 40° F. below zero; and yet the extreme of summer heat is but a few degrees less at Saint Paul than at New Orleans, 97° to 104°. The range between the extremes is about 65° more at the source than at the mouth of the river. The annual mean temperature at New Orleans is 69°; at Cairo, 45°.
Floods. The mean annual precipitation over the entire basin is estimated by Humphreys and Abbot at 20.8 inches. The estimated discharge of the river is 610,000 cubic feet of water per second. The precipitation, however, is subject to great variations at different seasons—which fact, together with the sudden melting of the stored-up snow in the spring, causes considerable variations in the volume of the various tributaries. Fortunately, all are not at their highest at any one time; for if they were, probably nothing artificial could resist the force of the accumulated waters. The regions from which the floods come are so far apart and differ so widely in climate that, as a rule, one flood passes before another comes. As it is, the volume of the floods that come is sufficient to make a variation of over fifty feet between high and low water marks. The greatest difference recorded at Cairo is 53.2 feet, and at Vicksburg there has been known to be a difference of 55 feet. At flood times the water at Cairo is 320 feet above the mean tidewater at the mouth of the river. At low water it is 274 feet above mean tide. This fall in a channel 1097 miles long fully accounts for the great velocity of the current, which varies from three to six feet a second, according to existing conditions. In high floods the river formerly overflowed nearly all the surface between the mouth of the Ohio and the Saint Francis River in southeastern Missouri and eastern Arkansas, filling the lakes and lagoons of that region, and then flowing by numberless channels to the White River and Arkansas, the Bayou Macon, Washita, Red, and Atchafalaya rivers into the Gulf. Even since the levees have been built (see below), the river sometimes breaks through these; its waters then flow down the slope of its ridge, and collect in the lowlands, forming lakes. These rise gradually, extending up the slope of the ridge, and so flooding the farms and plantations. In the spring of 1897 a flood created many crevasses in the levees and swept over a great tract of territory, causing heavy losses in stock, crops, and other property. On March 14th the water reached the highest point ever recorded at Memphis, Tenn. On April 5th, according to an official statement of the Department of Agriculture, the total area under water was 15,800 square miles, the submerged land being for the most part in Missouri, Mississippi, Tennessee, Arkansas, and Louisiana. Further damage was subsequently caused by breaks in the levee at Biggs and La Fourche Crossing, La., which resulted in the flooding of large tracts of land below Vicksburg, Miss. It was estimated toward the close of April that 20,000 square miles, containing 46,930 farms, according to the census of 1890, were under water. According to some estimates, from 50,000 to 60,000 persons suffered serious losses, from the floods. The Citizens' Relief Committee of Memphis cared for large numbers of the refugees. The destitution was so widespread, however, that President McKinley sent a special message to Congress, which appropriated $200,000 for the immediate relief of the sufferers.
Early Measures of Relief. The first attempt to guard the lower part of the valley against the river floods was made early in the eighteenth century, when the French Governor, De la Tour, ordered embankments for the protection of New Orleans. In the old slave days, when labor was cheap, each planter erected barriers on or near the river front of his own ground. These were called levees, and were simply artificial mud banks, sometimes strengthened with ribs or foundations of timber, sometimes not. So long as they were watched carefully and kept in good repair, they afforded comparative safety to the grounds behind them, except in the highest floods, and as time went on the common interest of the Valley States dictated harmonious action all along both sides of the river. The development of the levee system brought about the enactment of such local laws as were best calculated to serve the public interest, and gradually the levees became recognized factors of public welfare and were jealously guarded. The most reckless and negligent planter was forced to keep his own levees in repair, and in places where private interest was not sufficiently strong to force the building of these earthworks, the town or the State assumed the burden. In 1828 the State of Louisiana began to take vigorous action for the more complete protection of its delta lands. In 1836 and 1838 several of the great side channels by which inundations had come were closed at the expense of the counties, and the question of the closing of all the overflow channels, so as to confine the stream to one bed in all stages of water, was the subject of much excited difference of opinion. The closure party prevailed, and one by one the side outlets of the Mississippi were cut off by levees, so that by 1844 every old bayou outlet for 600 miles up the west hank had been effectually closed. The results were even more satistory than had been expected, so that the levee system was entered upon with increased spirit by the States bordering the river, and the aid of the General Government was invoked to unify the work. Congress, in 1850, ordered thorough topographical and hydrographic surveys of the whole of the lower Mississippi Valley under the direction of Capt. A. A. Humphreys and Lieut. H. L. Abbot, who began work immediately; but the report was not submitted until August, 1861. It recommended confining the river to a single channel and making the levees higher at all points, and estimated the cost of carrying out this recommendation at $17,000,000.
At the outbreak of the Civil War these levees were in better condition than ever before. Substantial levees had been constructed on the east side up to the northern line of the State of Mississippi, including one of great magnitude across the Yazoo Pass—the largest of all the outlets closed. On the west side the levees had been completed to the mouth of the Arkansas. Louisiana alone had expended up to that time $18,000,000 on the levees of the main river; $5,000,000 more on its great side outlets, the Atchafalaya, Plaquemine, and La Fourche; and $1,000,000 on the shore of the Red River. The State of Arkansas had spent $1,000,000; Mississippi, on her water-front of 444 miles, $14,500,000; and the State of Missouri, on her front of 140 miles, $1,640,000. The total expenditure by individuals, parishes, and States up to that time, on about 2000 miles of the river shore, is estimated by C G. Forshey, of New Orleans, at upward of $41,000,000. without counting the cost of maintenance. Before the four years' struggle began to draw to a close, however, the levees had fallen into decay. There were breaks here and there that destroyed the system, and the planters were too poor to hire the necessary labor to rebuild. Something had to be done to meet the difficulty, and that too before dire disaster had fallen upon the people living in the valley.
The Mississippi River Commission. A commission under this name was created by act of Congress of June 28, 1879, and consists of seven persons, three of whom are army officers selected from the Corps of Engineers, one from the Coast and Geodetic Survey, and two civil engineers and a lawyer from civil life. The commission was directed by the act to complete surveys of the entire river, from headwaters to mouth, and to take into consideration such plans and estimates as will correct, permanently locate, and deepen the channel and protect the river banks. The prevalent idea, therefore, that the work of the commission is confined to the lower river is erroneous. For the expenses of the surveys, examinations, and investigations conducted by the commission for the first ten years of its work, considerably over a million dollars were appropriated and expended. This is entirely independent of the appropriations made for the actual works of improvement, which were begun in 1881, and which have cost thus far, in round numbers, over $14,000,000. In the various appropriation bills for this purpose the commission has been restricted carefully in the scope of the work to the exact purposes defined in the creating act. In making the preliminary surveys ordered by Congress, the commission found it had to deal with a work of most extraordinary difficulties. The main portion of its labor was called on for the lower river; that is, from Cairo to the Gulf. The distance in a straight line is less than 600 miles, but by the windings and twistings of the river it is some 500 miles longer. Forever bringing down its own obstructions and dropping them in its own path, the river is forever attacking or running around those same obstructions, changing its course continually. The difficulty due to the enormous amount of detritus in the river may be realized when it is said that the amount of sediment brought down annually is estimated by C. C. Babb at 406,280,000 tons, and other geologists have made similar estimates. Straightening the river, as has been at various times popularly suggested, would, on account of the huge volume of water, turn it into an uncontrollable torrent. Dredging is not practicable, as the river frequently deposits as much as fifteen feet of silt in one place in the course of a single year, and as frequently removes it in the course of a single week or less. The quality of the soil itself also makes diking and revetting peculiarly difficult. The force of the tremendous current of the river directed against the foundation of any work that may he placed on its banks is likely at any time to remove that foundation. When the report of the commission was made in 1880 it was decided to combine the jetty and levee systems. There were few natural advantages to be utilized, and it was recognized that nothing could be done that could be declared absolutely permanent, and that the actual river bed could never be made to hold all the flood waters that were certain to come down. What has been attempted, and in some measure accomplished, is to take advantage of the river's own peculiarities, and by strengthening natural obstructions, here and there, rather than by removing obstacles, to persuade the stream, instead of forcing it, to follow a given route.
Jetties or Contraction Works. The system will be given more in outline than detail, as the latter are far too numerous to be more than barely mentioned. The natural banks of the river, in those places where the current sets against them, and is likely to wear them away, are strengthened by revetment work. The character of this revetment varies somewhat according to circumstances, but, generally speaking, is of two kinds. The first is a kind of soft bottom put on the bed of the stream at the point of greatest erosion. This consists of what are called mattresses or hurdles, which are constructed of mats of brush woven and fastened together with wire strengthened with a sort of latticework of heavy timbers placed on the banks and secured by a substantial ballast of rubble-stones. A crib of timbers is first constructed in sections, amounting in all to dimensions sufficient to cover the place which is to be protected. Over this is laid a carpet of heavy brush, with the twigs of fibre running generally in parallel lines. Over this is laid another carpet of similar construction, with its fibres crossing that of the first at an angle usually less than a right angle, and the two are knitted or sewed together with strong wire. Sometimes a third carpet may be laid, with the brush lying at still another angle. Then another crib or lattice-work of heavy timber is laid on these carpets, and the whole is bound together with wire, or another series laid on top if extra strength and weight are needed. The entire contrivance is then placed in position, covering the bottom of the river from the centre of the channel to the margin of the bank. As a matter of course it is necessarily handled in sections, but the sections are placed and fastened together so as to form a continuous carpet when laid, and they are then heavily ballasted with rubble-stone, laid systematically to form an uncemented pavement over the carpet. It is found that this practically secures the mattress in position for a considerable time under ordinary circumstances, and actually prevents the eating away of the banks by diverting the course of the current back to the desired channel. Generally it occurs that the action of the river before this treatment is applied to it has made the bank uneven. Sometimes it will even overhang the river a little, and it is necessary to smooth the surface to afford an even bed or floor on which to lay the mattress. Instead of digging this away, the familiar method of hydraulics is utilized. With a powerful engine a stream of water is pumped through a hose, and the soft earth is readily washed into shape. The ultimate purpose of these mattresses and other devices is to secure an approximately uniform width between the banks of about 3000 feet. When this is done it is believed that the bottom will be scoured out by the current, so that a depth of not less than sixteen or eighteen feet will be secured throughout the lower river. The permeable dike is a contrivance used in many places where it would be impossible to lay mattresses, where there may be, in fact, no bank to lay them on, but a wide stretch of slack water reaching out into a lagoon. These dikes are of simple construction, consisting of rows of piles driven as firmly as may be in the soft bottom. The piles are placed from two to five feet apart, and between the rows quantities of brush are placed and fastened. The water passes through these works freely at first, but being checked by the partial obstruction, it drops the sediment with which it is so heavily charged, and itself completes the dam which confines its course. These dikes are found to be very effective substitutes for complete dams, and are put where it would be difficult, if not impossible, to build a solid dam in the first place. More substantial, or rather more compactly built dams are placed at some points where there is a tendency on the part of the river to form cut-offs. (See section Description of Natural Features.) This tendency is perhaps the thing most dreaded and most carefully guarded against.
Levees. It has been found that, in order to meet the whole question scientifically, it would be necessary to build a double line of levees on each side of the river. The inner line is built to define the course of the channel and to prevent floods; the outer line, which is located far down the river ridge, is designed to protect the farms and plantations from the invasion of the back water in case the front levee is broken. The levee is in certain places the only possible safeguard. Cairo, Ill., affords a conspicuous instance of this. No revetments or dikes could possibly guide the current so that it would flow past the city without overflowing it, for the simple reason that the city is below high-water mark. It is of necessity entirely surrounded by a levee that rises some fifty-five or sixty feet above low-water mark, or ‘zero,’ as it is called on the Government records. The keeping of the works in repair is a matter of vital importance; constant watching and constant strengthening are the only things that can successfully combat the action of the rushing stream.
Other Problems. The characteristics of the banks are so different that the various localities offer special problems in themselves, and must be handled without reference to conditions that obtain elsewhere. The bluffs are threatened in one place, while in another the opposite low bank is attacked, and the river devotes its energies toward cutting a new channel. Revetments are sometimes on the bluff side, then again on the opposite; basins are occasionally cut in the soft bottom ground where the old river bed used to be, and spur-dikes are in other places the only remedy.
The mouth of the Red River brought several vexed questions before the commission, and the practical result of their conclusions will not be known until the works now in progress are completed. It is feared that the bed of the Atchafalaya, the present main outlet of the Red River, will enlarge sufficiently to convert the entire country between it and the Mississippi into an arm of the sea. The only safeguard seems to be by a series of dikes and submerged dams to turn the low-water flow of the Red River all into the Mississippi.
Another serious problem was presented by the bars at the mouths of the delta, which have been a serious obstacle to vessels entering the river. This was solved by the celebrated engineer James B. Eads. He selected the South Pass, and by the construction of jetties which narrowed the channel at its mouth, and thus increased the velocity of the current, he made the river cut its own bar away, and obtained a depth through the bar and throughout the pass of 34 feet, with width adequate for all purposes of navigation. This improvement has resulted in establishing New Orleans as the leading seaport of the South. See the section Jetties.
It is well understood that the whole work of regulating the river is likely to prove a slower process than was at first supposed, and that to be efficient it can only be gradual and progressive. It is a work of great magnitude; it is supposed that not less than $75,000,000 will be needed to put it even in approximately good shape. The work has, however, suffered greatly from inadequate and intermittent appropriations, which have interfered with a systematic and economical administration of its affairs.
For the history of the discovery and first settlements of the Mississippi, see De Soto, Hernando; Hennepin, Louis; Iberville, Pierre; Joliet, Louis; La Salle, René; Marquette, Jacques; Schoolcraft, Henry R.; New Orleans; Saint Louis; Saint Paul, etc. For shipping statistics of the Mississippi see the article United States, section on Shipping on the Mississippi System. See, also, articles on the principal tributaries.
Bibliography. Humphreys and Abbot, Report on Physics and Hydraulics of the Mississippi River (Philadelphia, 1861); Eads, Physics and Hydraulics of the Mississippi River (New Orleans, 1876); Ellet, On industries of the Delta of the Mississippi (Philadelphia, n.d.); Glazier, Down the Great River (ib., 1888); Corthell, History of the Jetties at the Mouth of the Mississippi River (New York, 1880); Johnson, “Protection of the Lower Mississippi Valley from Overflow” and “Great Floods on the Lower Mississippi,” in Journal of the Association of Engineering Societies, vols. ii. and iii. (Philadelphia, 1885); Ockerson and Stewart, Mississippi River from Saint Louis to the Sea (Saint Louis, 1892); Levasseur, La question des sources du Mississippi (Paris, 1894); Brower, The Missouri River and Its Utmost Source (Saint Paul, 1897); Ockerson, The Mississippi River: Some of Its Physical Characteristics (Paris, 1900); and the Annual Reports of the Mississippi River Commission (Saint Louis, 1879 et seq.).