MISSISSIPPI RIVER IMPROVEMENT. 



603 



In common years the rise begins about the 1st of 

 March and increases rapidly until the river's bed, 

 glutted, throws the superfluous water through innu- 

 merable channels into the back reservoirs. The in- 

 crease of elevation is then slow, and a diurnal decre- 

 ment is perceived, owing to the continually increased 

 surface tnat must be overflowed. Many outlets occur, 

 . . . but few lakes, in the true acceptation of the term, 

 are found. The bunks of the river are generally above 

 overflow, and are composed of the most productive 

 soil, gradually sloping back by an inclination that 

 gives from one quarter to one and a quarter miles 

 width before the plain sinks below the surface of high 

 water. 



Without human testimony, physical reasons 

 compel the belief that, before the lands adja- 

 cent to the main stream and its tributaries 

 were cleared, the elevation of the river-banks 

 conformed more nearly to the flood-plane of 

 the river than at present. Levees undertaken 

 for reclamation must now maintain the former 

 height of the banks to preserve navigation. 

 Bank-building near the mouth of the river is, 

 at this moment, progressing under the same 

 conditions, and each crevasse demonstrates this 

 truth. At Bonnet Carre the deposit, extending 

 back to Lake Pontchartrain, four or five miles 

 distant, is ten to twelve feet high. Through 

 these sand-hillocks outlets probably drainage 

 canals of the old plantations keep themselves 

 open. The banks of cut-off lakes add their 

 conclusive evidence. In front of Lake Con- 

 cordia the main height of the bank of the pres- 

 ent river is one hundred and forty-eight feet, 

 while the height of the bank of the old river 

 is one hundred and fifty- three feet. In esti- 

 mating this difference a uniform average flood- 

 height is supposed, and there is no proof to the 

 contrary. G. W. R. Bayley, before the Ameri- 

 can Society of Civil Engineers, says: "There 

 is no evidence that the normal flood-line of the 

 Mississippi River, from Red River to the head 

 of the passes (except where affected by cut-off), 

 is a fraction of an inch higher now than in 

 1717, before the commencement of the levee 

 system, bat there is evidence that it is not 

 higher/' Professor Forshey concurs in this 

 opinion. General Warren sums up the discus- 

 sion before that enlightened body thus: " Ob- 

 viously, we can not get the increased scour 

 until we build the levees and close the outlets, 

 so as to confine the escaping flood-waters." 

 High-water marks at Natchez, dating back to 

 1802, compiled by Humphrey and Abbot, and 

 brought down to date by the United States 

 Engineer Corps, strongly corroborate this view. 

 Beginning thirty years before the extension of 

 levees above Red River, they show no change 

 in the flood-elevation during eighty years. The 

 effect of closing the outlets of the Atchafalaya 

 is similar. 



The flood -plane has not been raised since the 

 settlement of the country. The clearing of the 

 forests has accelerated caving, and prevented 

 the gradual elevation of the banks by arrest 

 and deposit of sediment. Levees, averaging 

 eight feet in height, are part of the normal 

 bank. 



These levees extend on both banks of the river for 

 a distance of sixteen hundred miles, out of a total al- 

 luvial shore-line of about twenty-two hundred miles. 

 They attain, occasionally, a height of from fifteen to 

 twenty feet, exclusive of the dikes, closing well-defined 

 outlets, when they frequently have a height of forty 

 feet. Were these dikes removed, they would aduut 

 the main supply of the largest rivers in the valley. . . . 

 The commission has already reported adversely to the 

 influence of such lateral channels. Also, below many 

 of the largest of these artificial embankments are parts 

 of the river where navigation is now exceeding 1 }' dim- 

 cult. . . . Certainly the maintenance of volume is 

 important in preventing such obstructions. But, apart 

 from these as extreme cases, is not the retention of 

 such part of the flood-discharge as is now held by an 

 average height of seven or eight feet of artificial em- 

 bankment necessary to maintain the navigation of the 

 river in its present condition? Without these, the 

 most moderate floods would overtop the banks and 

 disperse their waters through the innumerable lateral 

 swamp-drams from bluff to bluif, with loss of velocity 

 and consequent obstruction of channel. If this de- 

 scription ot the present status of levees is true, it must 

 be borne in mind that the causes by_ which it was 

 brought about are not local, but exist in every tribu- 

 tary valley. The disturbance of the forest and sod- 

 covered surface, and the undue precipitation of drain- 

 age, extend to the head-waters of the Mississippi, of 

 the Ohio, and of the Missouri, while the remedies 

 which have been opposed to these evils the placing 

 artificial barriers to such dispersion of flood-waters as 

 would have been highly injurious to navigation, and 

 the maintenance of these barriers have been exclu- 

 sively done by the riparian States and proprietors. 

 While, doubtless, the motive was reclamation and 

 self-protection, we believe that much of the benefit 

 accrued to other sections of the country, equally inter- 

 ested in the navigation of the river ? and equally re- 

 sponsible for its deterioration. Without discussing 

 the equity of this condition of affairs, we earnestly 

 represent that it is extremely hazardous, as a system 

 of such character and magnitude can only be main- 

 tained by unity of administration, by promptness of 

 action, and by large expenditures. Neither of these 

 is, or can be, secured while the work is left under the 

 present management. Its history sustains this state- 

 ment. 



The report proceeds to array the opinions of 

 competent authorities who have studied the 

 subject in its scientific aspects, all favoring the 

 levee and jetty systems, and reprobating the 

 outlet theory. It then cites instance after in- 

 stance where closing outlets and regulating 

 banks have washed out channels and removed 

 even such obstacles as- the raft in the Atcha- 

 falaya. In the Lafourche, whose lower portion 

 is unleveed and free to discharge itself laterally 

 by numberless outlets, the effect has been to 

 narrow the channel one third or fourth of that 

 above, where it is confined. Between the 

 levees it has not filled to any appreciable de- 

 gree ; the elevation takes place where the out- 

 lets occur. The obstruction there backs up the 

 water and raises the water-line, so that year by 

 year the height of the levees must be increased. 

 Red River runs through an alluvial soil, like 

 the Mississippi, and its levees have undoubtedly 

 lowered the river-bed. The President of the 

 New Orleans and Red River Transportation 

 Company, to show the effect of jetties on river- 

 bars, states that Snaggy- Point Bar, seventy -five 

 miles above the mouth of the river, and Alex- 

 andria Bar, three miles below the town of that 



