mended that this sum be allotted to the construction of levees. The entire allotments made to that part of the work out of the appropriation were as follows: All these allotments were approved by the Secretary of War. Except for the restrictions and directions contained in the provisos to which reference has been made, the Commission would have regarded the first allotment of $400,000 as a suitable portion of the entire appropriation to be expended in the construction of levees. But the language of the act, literally construed, was an express direction to complete, or at least go forward with, that part of the work directed by the act which was clearly practicable, and omit that part which was believed to be impracticable until Congress could take further action on the subject. And this was the course taken. It may be said further that the time is opportune for pushing the , levee work with vigor. The full benefit to be expected in the improvement of the channel by concentration of the flood discharge can not be realized without complete closure of long lines of alluvial front. In the early reports of the Commission it was recommended that the closure of the Yazoo and Tensas basins be taken as objective points, and that end has been kept in view throughout the work. In expenditures for the construction of levees the Commission has, as a rule, sought the co-operation of the State and the local authorities and private citizens interested. This course has stimulated the people of the alluvial valley to the most strenuous exertion. The total allotments for levees made by the Commission since its organization, out of the appropriations made by Congress, may be stated in round numbers at $2,600,000. The Commission is not in possession of exact information as to the amount expended in like work, during the same time, by the local authorities and citizens, but estimates the sum approximately at $4,350,000. By means of this cooperation the Yazoo front has been closed, the lines requiring, however, some additions and strengthening before they can be regarded as complete; and the work on the Tensas front is so far advanced that it is hoped that another season will suffice for its completion. The past year has witnessed a great awakening of enterprise in the Yazoo and Tensas basins, stimulated in part, no doubt, by the prospect of protec tion against overflow, and which in turn will create means and motives for the protection and preservation of the levees constructed. So that, considering it to be part of the plan of improvement that the levees shall be built and maintained for the betterment of the channel, as has been constantly recommended by the Commission, and as is declared in the act last passed, and to be to the interest of the Government that as large a share of the cost as possible shall be paid by the local authorities or the people, it is clear that the present is a favorable time for pressing the work. The convictions expressed by the Commission in its letter to the Secretary of War, touching the futility of an attempt to improve the river channel by levees and contraction works alone, are still entertained, and have been strengthened by the experience of the present season. It would be impossible for works of improvement to operate more successfully than have those at Plum Point Reach. The regulated channel has maintained its width and depth and the current its location and direction, with no substantial variation. These results have been obtained by permeable contraction works and works of bank protection combined. They could not have been obtained by either alone. The Commission believes that it would be impossible for any intelligent man to go to the reach and look at what has been done and the results which have been achieved without seeing clearly that that part of the work which has operated, like the key of an arch, to hold all other parts in place has been the revetment in Fletcher's Bend. At Lake Providence Reach as great depth of channel has been obtained as at Plum Point, but the channel has not retained its location and direction as steadily, and in the present situation there is less promise of permanence of the good results obtained. This is accounted for by the fact that the revetment work in that reach is less complete and has suffered more injury, and that there has been, in consequence, more caving of bends and more shifting of the channel. The practical execution of works for bank protection upon such large scale and in situations so difficult as those found on the Lower Mississippi was at the beginning a problem transcending the experience of engineers. There was no road to success except by experiment. Since then much valuable experience has been gained, improved methods of construction have been devised, better results have been obtained, and the cost, considering the results, lessened. The form of revetment mostly employed consists of continuous mattress under water, and graded bank, grillage, and stone covering above the low-water line. At New Orleans a revetment has been employed, consisting of submerged spurs placed against the caving bank. This form was cheaper than a continuous mattress would have been at that place, and appears so far to be successful. At the lower portion of the Memphis city front a revetment has been constructed consisting of detached spurs extending to high-water mark. This was more expensive than a continuous mattress would have been at the same place; but in the situation there presented, the bank to be protected being at the foot of a high, crumbling bluff, the spurs seemed to be the better form. This work was done under the direction of Capt. S. S. Leach, the district officer in charge, but mainly at the expense of private citizens. It has passed through one flood without injury and gives every promise of permanent success. These three forms of revetment-the continuous mattress, the submerged spur, and the spur extending to high-water line-are all that have been tried. A fourth form is possible, consisting of discontinuous mattresses placed at intervals against the bank. It is possible that in some situations this would be found practicable and economical; but it is to be remembered that in such constructions as these experiments in search of cheapness are themselves very expensive. The Commission is not unaware of the grave responsibility which it assumed in declining to recommend the execution of work in the form contemplated in the proviso found in the act of August 5, 1886; but the Commission was then of the firm opinion, and still is, that the prohibition of all bank protection makes the work of improvement by regulation of the low-water channel impossible. Holding these views, the Commission would be wanting in the faithful discharge of duty if it should fail to urge upon Congress a reconsideration of the subject. It it particularly to be regretted that such a change should be proposed in the conduct of work in the Plum Point and Lake Providence reaches. In these the work done has been a combination of contraction and revetment. It has been successful in the highest degree. It is now near completion. In the absence of unlooked for disaster, and by prompt resumption of work with sufficient means, it is believed that $250,000 will suffice to complete the work undertaken at Plum Point and $1,500,000 that at Lake Providence; and against a change of plan at this time, which it is believed will imperil all the good results attained in those difficult reaches, the Commission feels compelled to protest with all the earnestness which is consistent with the respect due to the superior wisdom and authority of Congress. IMPROVEMENT OF BAYOU PLAQUEMINE. There is one measure of partial relief to the commerce of the Atch afalaya which may also be of some value to the commerce of Red River, while works for its more complete improvement are going on, which the Commission recommends to the attention of Congress. It is the opening of the Bayou Plaquemine from its junction with the Atchafalaya to the town of Plaquemine, on the Mississippi. There is a considerable and growing commerce in the Atchafalaya Basin, which finds its present outlet into the Mississippi by way of Old River. It is not to be expected that that outlet can be kept open at low water until improvements can be completed that will require several seasons for their finishing. If that commerce could have access to the immediate bank of the Mississippi at Plaquemine it would not be entirely suspended by the closure of Old River; and until the proposed new channel rorth of Turnbull's Island is developed, it would be some relief to the Red River trade to be able to reach the Mississippi at Plaquemine when Old River is shut up. The expense of such improvement of the Bayou Plaquemine and its connections as would suffice for this purpose would not be great. From information gathered from personal inspection and other sources, the Commission is of the opinion that $40,000 would secure the advantages proposed. If such an improvement is to be undertaken at all, it is very desirable that it shall be completed before the next low-water season, which could not be accomplished after the passage of an appropriation bill at the coming session of Congress in the ordinary course of business. The Commission recommends, therefore, that the Secretary of War be authorized to use at his discretion not exceeding $40,000 of money heretofore appropriated for work in the Atchafalaya and Red rivers, or for the improvement of the Mississippi River below Cairo, in the improvement of Bayou Plaquemine. The SECRETARY OF WAR, Q. A. GILLMORE, President Miss. River Comm., Lieut. Col. of Engineers, U. S. A. (Through the Chief of Engineers.) R. S. TAYLOR. I am not of the opinion that levees can be used either with economy or usefulness to improve the low-water navigation of the Mississippi River; hence, under the proviso of the river and harbor bill of August 5, 1886, "that no portion of this appropriation shall be expended to repair or build levees for the purpose of reciaiming lands or preventing injury to lands or private property by overflows," I do not concur in the advisability, under the law, of spending on levees nearly two-thirds of the appropriation not limited to specific points. The value of levees as a means of improving low-water navigation has been much discussed, and some results of experience are very desirable. At Plum Point a levee was built in 1886-'87, which, in the high water of 1887, turned into the river a large amount of flood-water which before had escaped over Plum Point. A cutting down of shoals and enlargement of section in consequence is reported, and was to have been expected. But the question at issue is whether such confinement of flood-waters increases in a marked degree the navigable low-water depths on the shoalest crossings. Prior to the construction of the levee, the least depths on the Plum Point crossing had been for some years oftener over than under 9 feet, sometimes reaching 10 or 12 feet. Yet on October 27, 1887, the depth on the Plum Point crossing was but 9 feet, this being eight months after the completion of the levee. The river was very low (-0.5 on the Plum Point gauge), but as the contraction works alone might have cut down the bar to this depth, evidence that this levee has improved navigation is wanting. The Commission estimate the cost of completing the work in the Plum Point and Lake Providence reaches at $250,000 and $1,500,000, respectively. Even if work were to be confined to the 14 miles at Plum Point, and to the 19 miles at Lake Providence, to which previous work has been mainly confined, I deem these sums much too small. A reach can be considered completely or permanently improved only when its works have been carried so far that the reach and its works are safe for many years against changes within its limits, and when the only danger of any serious injury is from an attack at the upper end of the works by the unregulated river above them. To stop short of this is to increase steadily the amount of work annually destroyed by the river itself. NEW YORK, December 9, 1887. C. B. COMSTOCK, Lieut. Col. of Engrs., Bvt. Brig. Genl. I concur in the above report, except as regards the building of extended levees as means of improving navigation. Our experience with levee construction has led me to the conviction that no general or very extensive system of levees for the Lower Mississippi River would form part of a proper plan for the deepening of the low-water channel at those "crossings," comparatively few, at which there is now less water in the low-river season than commerce requires. I can not, therefore, concur in the statement that "the other branch of the work directed by the act, consisting of levees designed to secure uniform width of the Ligh-water channel, is of such nature that it can be carried forward to any extent in advance of other work, with economy and usefulness." HENRY MITCHELL. List of Appendices accompanying the foregoing report. APPENDIX A.-Report of the Secretary of the Commission. Page. 2760 1. Geographical positions near Cairo, Ill., from lake survey, 1876. 2772 2772 3. Geographical positions between Greenville, Miss., and Donaldsonville, La......... 2775 2815 2862 4. Final reports on discharge observations of 1884-'85. 2864 APPENDIX B.-Report of the secretary of the committee on construction. APPENDIX E.-Report of Capt. W. T. Rossell upon operations in the third dis- APPENDIX F.-Report of Capt. Dan C. Kingman upea operations in the fourth district... 2675 2881 2-93 2005 2906 2909 2910 2911 |