For details and a discussion of the Atchafalaya problem, see report of Captain Kingman, Appendix I. REMARKS. No appropriations for the expenses of the Mississippi River Commis sion have been made since July 7, 1884. The result has been that the Commission has been unable properly to perform its duties or to examine the works for which it is reponsible. No inspection by the Commission of the works along the river has been possible since November 1885, on account of lack of funds. The river and harbor act of August 5, 1886, limited the Commission in the use of revetment to so great a degree as to make it unadvisable to attempt much work on the Plum Point and Lake Providence reaches with the funds it provided. The result of this limitation has been los of work and increase in the final cost of improvement. The last worl of any importance on these reaches was with the funds provided by the river and harbor act of July 5, 1884; thus, during a long interval o time, the works have been exposed to the attacks of the river, and fo all wood-work above water to great injury by decay. In the Plum Poin Reach, while some work has been lost, the injury as yet has not beer arge, but the works in the Lake Providence Reach are now in a very un latisfactory condition. ESTIMATE OF FUNDS FOR THE MISSISSIPPI RIVER COMMISSION FOR THE FISCAL YE ENDING JUNE 30, 1890. Sundry civil bill. Mississippi River Commission: For salaries, inspections, and traveling expenses of the Mississippi River Commission; for printing and telegraphing; for office expenses and miscellaneous $35,0 River and harbor bill. For surveys and examinations of the Mississippi River from the Head of the $150,0 For improving the Mississippi River from the Head of the Passes to the mouth of the Ohio River For work at Columbus, Ky.-continuing improvement 4,000,0 25,0 APPENDIX A.-Second paper by General Comstock, on effect of overflow on velocity' and flood height. APPENDIX B.-Report of the secretary of the Commission. 1. Elevations and descriptions of secondary triangulation statious, Cairo to Donaldsonville. 2. Geographical positions of tertiary points, Keokuk to Cairo. 3. High-water marks of 1888. 4. Low-water gauge-readings, 1887-'83. APPENDIX C.-Table of low-water soundings on bars, 1886-'87. APPENDIX D.-Report of the secretary of the committee on construction. APPENDIX E.-Report of Captain Rossell upon operations in the first district. APPENDIX F.-Report of Captain Rossell upon operations in the second district. APPENDIX G.-Report of Captain Leach upon operations in the first and second dis tricts to November 1, 1887. APPENDIX H.-Report of Captain Rossell upon operations in the third district. 1. Report of Captain Rossell upon Vicksburg survey. APPENDIX I.-Report of Captain Kingman upon operations in the fourth district. 1. Improving harbor at New Orleans, La. 2. Rectification of Red and Atchafalaya rivers. 3. Construction and repair of levees. Plam Point Reach List of plates accompanying the foregoing report. November, 1887, Appendix E. May, 1888, Appendix E. Changes in bank lines, Appendix E. Memphis Reach and Harbor, Appendix F. Hopefield Bend, Appendix F. Greenville Harbor improvement, Appendix H. Lake Providence Reach, Appendix H. Teksburg and Mississippi River survey, Appendix H. NOTE.-In consequence of the resignation of Professor Henry Mitchell, there is a Tacancy in the Commission. APPENDIX A. EFFECT OF OVERFLOW IN DIMINISHING VELOCITY OF MISSISSIPPI RIVER, AND EFFECT OF LEVEES ALONG YAZOO FRONT ON FLOOD HEIGHTS IN 1882 AND 1883. SECOND PAPER. Paper presented by General C. B. Comstock at a meeting of the Commission on board steamer Mississippi November 10, 1885. 1. In a paper dated March 15, 1834, addressed to the Mississippi River Commission and published in its annual report for 1885, I concluded: 1st, that the observations of the Commission give no support to the theory "that when flood escape over the Mississippi River banks begins the velocities in the main river are checked and de posits induced; and the checking of velocity arises from this escape;" 2d, that the theory that levees built in 1882-'83 reduced the flood heights at Vicksburg in 1883 as compared with 1882 is not needed to account for the facts." Under date of August 28, 1885, Maj. C. R. Suter submits to the president of the Commission a paper prepared in accordance with Major Suter's instructions, dissent ing from those conclusions. As those conclusions were correct, the paper needs examination. The first conclusion will first be considered. The majority of the Mississippi Rive: Commission, in their report for 1883, say: "The loss of volume through high-water outlets causes both a diminution of velocity and a deflection of the thread of movement of the stream towards the outlet, accompanied by loss of the power necessary to transport the material with which it is loaded." If it is true that when overflow begins, the velocity in the river is diminished by the overflow accurate velocity observations in the main river at the time of flood escape should establish that fact. In my paper of March 15, 1884, I showed that the Commission was then in possession of such observations at twelve points where over flow occurred, scattered from near Saint Paul to the Red River. At eleven of these points there is no decrease in the velocity of the main river, as it rises from the stage when overflow begins, to its maximum stage. At one. Hays' Landing, there is a slight decrease. At eight of the twelve stations the velocity steadily increases during this period. At three others the velocity remains about the same during this period. At two of these three, Grafton and Clayton, this constancy of velocity dur ing the overflow period seems to be accounted for by the local slopes. At the third, Hannibal, there are not sufficient data for discussion; at one out of the twelve namely, Hays' Landing, there are at times great irregularities in the velocities which are at least in part accounted for by the variation in slopes; but the velocities while the river was rising from its overflow stage, January 23, to its maximum height, March 20, were quite regular. From January 23 to February 27, the velocities varied little from 5.9 feet. Between February 27 and March 20 ten velocities were meas ured. They are well represented by a right line giving for February 27, 1882, gange equal 37.52 feet, mean velocity equal 6 feet, and for March 20, 1882, gauge equal 38.59 feet, mean velocity equal 5.5 feet. Here is a case where the velocities diminish about 0.5 foot as the river rises towards its maximum. But in my judgment this decrease of 8 per cent. in velocity is essentially accounted for by the fact that the fall in the water-surface from Lake Providence to Hays' Landing was 4.05 feet on February 27, 1882, and 3.28 feet on March 20, 1882, a decrease of 19 per cent., while from Hays' Landing to Vicksburg, on the same dates, the falls were 12.98 feet and 9.87 feet, a decrease of 24 per cent. These decreases above and below Hays' Landing indicate a reduction in the slope between the two dates of about 21 per cent. at this place, which, by the ordinary velocity formula would account for a diminution in velocity of 10 per cent., or slightly more than the observed diminution. No new theory is needed to account for the difference in velocity between the two dates, February 27, 1882, and March 20, 1882. 2. It seems scarcely necessary to say to the Commission that slopes over long distances are used because they are the only ones available for comparisons. While at high stages the slopes on the river become much more uniform that at low river, yet the changes in slope at a given station derived from stretches of the river above and below (the lower being 46 miles in length), must be regarded as giving only a general indication of the changes going on in the local slope, which, however, is valuable in the absence of more accurate information. The paper submitted by Major Suter contains remarks on the Fulton slopes and discharges of 1854, and those between Arkansas City and Vicksburg in 1882 and 1883. They add no information that affects my first conclusion. Every one knows that the upper part of a velocity curve is sometimes irregular. The important point is, do the velocities seriously decrease when the overflow stage is reached in consequence of the water escape over the banks, and does this checking of velocity cause deposits in the river below? If the checking of velocity without any change of slope to account for it, were a fact, it certainly ought to be shown at some one of our twelve discharge stations examined. As it is not, I can only repeat my first conclusion, namely, "that the observations of the Commission give no support to the theory that when flood Escape over the Mississippi River banks begins the velocities in the main river are checked and deposits induced, and that the checking of velocity arises from this escape." 3 The second conclusion in my paper of March 15, 1884, is, that "the theory that levees built in 1882-'83 reduced the flood heights at Vicksburg in 1883 as compared with 182, is not needed to account for the facts." Major Suter, in his letter, dissents from this. In my paper of March 15, 1884, my conclusion was based merely on the relative stages of the Mississippi River at Helena; on those of the White and Arkansas rivers at or near the time of the maxiVicksburg gange-reading, and on the probably smaller return flow from the Yazoo swamp in 1883 than in 1882. As the gauges from Lake Providence to Helena at the maximum stage (48.8) at Vicksburg, March 20, 1882, were higher than at the Vicksburg maximum stage (43.8) April 7, 1883, by amounts that increased from 5 feet at Vicksburg to 9 feet at Helena, this strongly indicated a smaller discharge in that part of the river in 1883. But in my paper no attempt was made to determine the precise discharges in 183, as the data for such a determination are far from sufficient for exactness between Helena and Vicksburg. As the paper submitted by Major Suter attempts to determine such discharges and give a value for the discharge at Vicksburg 13 at the maximum gauge-reading which for the main river at Vicksburg is $7,000 cubic feet per second larger than the corresponding discharge in 1882 (the Yazoo swamp return flow in both years being excluded), it becomes necessary to make the best estimate possible of these discharges in 1852 and 1883 in order to show that my conclusions were correct and that the paper is not. 4. On March 20, 1882, the Vicksburg gauge reached its maximum for the year of 4.75 feet, and the discharge at Hays' Landing on that day was 937,000 cubie feet with a gange-reading of 38.59 feet. On April 7, 1883, the Vicksburg gauge reached its maximum for that year of 43.80 feet, and the Lake Providence gange read 22.20 feet. What was the discharge at Hays' Landing on that day? There was no gange record at Hays' Landing, and the Hays' Landing gauge-reading must be compated from the Lake Providence reading. In 1882, at Lake Providence stage of 33.20, that gauge read on an average about 0.5 foot more than the Hay's Landing gauge, and 32.7 feet will accordingly be taken as the Hays' Landing gauge-reading, April 7, . If the Hays' Landing discharge curve of 1882 gave in the vicinity of this ange-reading but a single value for the discharge that value might be taken as an aproximation to the discharge there on April 7, 1883. Unfortunately, in the vicinity 33 feet it gives widely varying values for the discharge. It is known that slope, when mean depths vary little, exercises a powerful influence on velocity. Hence, in deeting from the discharge curve of 1882 a discharge which would most probably resent that of April 7, 1883, the dates in 1882 selected should have not only gaugePatings but also slopes as nearly equal as possible to those observed April 7, 1883. The nearest gauges read in both years were those of Greenville, Lake Providence, and Vicksburg, hence these must be used in comparing slopes. (It is not probable that the average values of the slopes would be much different if Hays' Landing were replace Lake Providence.) On April 7, 1853, the fall in the river surface from Greenville to Lake Providence was 19.13 feet, and from Lake Providence to Vicksarg was 12.98 feet. Since the return flow from the Yazoo swamp produces most effect on slope where it aters the Mississippi, and the effect nearly disappears in going up-stream, there is ason to believe that while the Yazoo swamp return flow is controlling the fall beteen Lake Providence and Vicksburg, the local slope at Hays' Landing will depend ach more closely on the average slope above than on that below. Therefore, since there was no time in 1882 when the two falls from Greenville to Lake Providence and from Lake Providence to Vicksburg were each equal to those falls on April 7, 1×83, We must take the date in 1882 when the fall from Greenville to Lake Providence was st nearly equal to the same fall on April 7, 1883. In 1882 the Greenville gauge record is missing from April 9 to April 22 inclusive, it as far as can be judged by the general form of the curve, and from a comparison it with that of Arkansas City, the fall between Greenville and Lake Providence the river surface, between February 1, 1882, and June 25, 1882, had no value less than 20.98 feet, which was reached on May 6, 1882. On that day the fall from Lake Providence to Vicksburg was 14.43 feet. From these data it is seen that at no time between February 1 and June 25, 1882, was the averags slope between Greenville and Lake Providence as small as on April 7, 1883; that its minimum value in the overflow period in 1882 was on May 6, 1882, when it was 9 per cent. greater than on April 7, 1883; and that on May 6, 1882, the average slope between Lake Providence and Vicksburg was 10 per cent. greater than on April 7, 1883. Both stretches agree in indicating a less slope at Hays' Landing at the later than at the earlier date, and giving double weight to the first it would follow that the Hays' Landing slope was 9 per cent. less in 1883. May 6, 1882, the Lake Providence gauge read 32.85 feet, and it read 33.20 feet on April 7, 1883. There is no information to show that the riverbed had changed between 1882 and 1883, so that we must depend on gauge-readings and the slopes for the discharge at Hays' Landing on April 7, 1883. The gauge-readings are practically the same, the evidence adduced above is strong that the slope was much less at the later date. The conclusion then follows that on April 7, 18-3, the discharge at Hays' Landing was less than on May 5 or 6, 1882, when it was ob served as 790,000 cubic feet. This value will, however, be taken for the discharge on April 7, 1883. 5. Having found 937,000 and 790,000 cubic feet per second as values for the discharges at Hays' Landing at the times of the maximum floods at Vicksburg in 1883 and 1883, those for the part of the river between Arkansas City and Cottonwood, 3 miles below Hays' Landing, where the return flow from the Yazoo swamp in 1882 began to come back into the river, may now be compared. Since no measures were made of the Yazoo return flow in either year, no reliable comparisons of discharges in the two years can be made between Cottonwood and Vicksburg, and the paper tends to confuse and mislead by neglecting this fact. March 20, 1882, the Hays' Landing observed discharge was 937,000 cubic feet per second. There was no escape between Hays' Landing and Cottonwood. The Mississippi River Commission Report for 1884 gives no escape into the Yazoo swamp between Hays' Landing and Arkansas City and (pp. 81-2) an escape of 82,000 cubic feet into the Tensas swamp between the same points. This, added to 937,000, gives 1,019,000 for the discharge at Arkansas City on March 19, 1882. Adopting the probably too large value, 790,000 cubic feet, previously obtained as the discharge at Hays' Landing on April 7, 1883, since the river from Hays' Landing to Arkansas City was below overflow stage, the same discharges may be assumed as approximations over the whole stretch. Tabulating the results for dates of maximum flood at Vicksburg in 1882 and 1883: From this table it is seen that the return flow of the Yazoo swamp in 1882, at the time of the maximum Vicksburg flood on March 20, was superposed at Cottonwood and below on the main river, which had a larger discharge than at the corresponding maximum, April 7, 1883, by about 147,000 cubic feet. The paper submitted by Major Suter gives the following table, in which the dis charges for 1882 agree with those given in the preceding table, while for 1883 they differ widely. The cause of the difference needs examination. It should be noted that the 668,000 and 905,000 cubic feet given in the last table as Vicksburg discharges are not such in fact, but are Vicksburg discharges minus Yazoo swamp return-flow, and hence they give no idea of the relative Vicksburg discharges in the two years. To get the discharge at White River on April 7, 1883, the paper takes the Helena discharge for April 3, 1883, from the Helena discharge curve of 1882 as 740,000 cubic |