NOTES.-The figures preceded by a minus sign indicate elevations above a plane corresponding to low water of 1879. "Mean smooth bottom" means the elevation of the bottom which would result if it were leveled up in such manner as to make the cuts equalize the fills. The areas remaining sensibly constant, this quantity is a good measure of the relative amount of scour or fill at any placeat different epochs. The site of Gold Dust and Plum Point dikes includes the whole area controlled by them. being all the bed of the river between the natural bank and the east line of the proposed regulated channel. The site of Osceola dikes includes all arcas between the natural bank and the west line of corrected channel. "Open river" is the proposed corrected channel of 3,500 feet width REPORT OF CAPTAIN SMITH S. LEACH, CORPS OF ENGINEERS, UPON OPERATIONS IN THE SECOND DISTRICT. UNITED STATES ENGINEER OFFICE, Memphis, Tenn., July 30, 1886. SIR: I have the honor to submit the following report upon the work of improving Mississippi River, second district, for the fiscal year ending June 30, 1886: Aside from the ordinary care and necessary repairs of property and routine office duties, the only work done in the second district during the fiscal year has been the repair of the most serious fault in the Hopefield revetment and the reballasting with stone of some portions of that, and of the Memphis revetment, which were originally sunk with sacks of gravel. The work of repairing this fault, known as No. 4, the beginning of which was noted in my report of November 30, 1885, was completed in the early part of Jannary, 1886. It comprised the complete renewal of the work for a distance of 1,140 feet, and the patching of a small break which occurred in October, 1885, immediately above the large one. The general plan of work was identical with that heretofore followed, comprising a continuous hurdle mat 150 feet wide, sunk below low water, a continuous upper bank revetment extending from the water surface to the top of the bank, with the interme diate zone of varying width covered by "connecting mats," discontinuous in structure, but firmly joined to the upper work and to each other, and lapping well onto the subaqueous mat. In construction especial attention was given to the internal strength of all the work, to secure junctions among the several parts, and with the old work above and below, and to anchoring to the bank both the subaqueous and shore revetments. As the defects in the present work in this locality have resulted mainly from a tendency of the upper re-. vetment to slide down the bank, the latter point (anchorage) was especially considered, and with a view of increasing the range of this experiment, as also in the hope of greater security, anchor cables were run out from the old work below No. 4. An experiment in drainage was contemplated, and directions given for the construction of a drain. The drain was begun at any early stage of the proceedings, but its completion was deferred until the river had risen several feet from the lowest stage. It was then hastily finished, but in such shape that it cannot fairly be credited with any good results which may follow, or charged with any bad ones. No important changes were made in the methods of administration. The late date at which the work was authorized left no time for advertising, for which reason purchases of materials and supplies were made in open market, except the stone, which, not being required until near the close of operations, was obtained on requisition from the secretary of the committee on construction. The 1,140 linear feet of bank in fault No. 4 were completely revetted at a total cost of $16.60 per foot. Several causes operated to increase this cost, among them the small amount of work to be done, the necessity of bringing plant from Plum Point and returning it; the serrated outline of the bank, requiring in the pockets nearly double the ordinary amount of shore work, and the fastenings to the old work above and below, which were tedious and expensive operations. This revetment, for which $16.60 per foot of bank may be taken as a liberal estimate, needs only the addition of 25 feet width to the subaqueous mat (175 feet instead of 150 feet), to become what, in the light of present experience, I would recommend as a standard for localities of ordinary importance in this part of the river. The addition of 25 feet would mean an increase of 163 per cent. in the cost of subaqueous work, which is now 49 per cent. of the whole. It seems safe, therefore, to estimate such work at $18 per foot for the future. The reballasting required 3,000 yards of rock, of which 280 yards were placed in the Memphis revetment, immediately below Wolf River, and the remainder on the Hopefield work, below fault No. 4. A classified statement of expenditures for this work is herewith. It was thought that with No. 4 repaired no apprehension need be felt for the safety of this work during the succeeding high water. This prediction has been fully verified, since all the rest of the work is to-day in practically the same condition as it was a year ago. The lowest fault near the end of the work has enlarged slightly, but has not caved back, and there has been a loss of a few feet at the extreme end, due to caving working up from below. The Memphis revetment is in perfect condition; but its completion to the end of the paved levee is of the greatest importance. The changes in the harbor of Memphis have been marked and beneficial. The corner of the sand-bar, which extended out from Hopefield Point, and around which the river made a very abrupt turn, has entirely cut away, as intimated in last report. The river now follows a more gradual curve, striking the Memphis front less squarely. The engorged section is now at the foot of Beale street. Memphis Harbor, above the Elevator, is now comparatively slack water, and some filling is taking place. These changes are entirely in the direction contemplated by the Commission when the plan for this improve ment was adopted four years ago. Two small breaks are reported to have occurred in the Long Lake Levee in this district during the last flood. No funds have been available for an examination of them. The following financial statement and general balance-sheet show the present condi tion of appropriations for this district: Appropriation for improving Mississippi River (act of July 5, 1884). SECOND DISTRICT. Balance on hand November 30, 1885, as per last report, including estimated liabilities.. $29,787 93 24,533 36 5,254 57 DR. 1885. Improving Mississippi River, Second District, Memphis Reach and Harbor. 1886. June 30 29,787 93 A table showing present value of plant is appended. SMITH S. LEACH, General Q. A. GILLMORE, President Mississippi River Commission. Approximate value of plant belonging to the United States and used upon the improvement of the Mississippi River, Second District. |