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Months Miles mainabove tained mouth. | during
Bellefontaine bridge, Missouri.
71 12 12 12 12 12 12 12 12 1138 12 12 12 12 12 12 12 12 12 12
Shore, cable and inclined
Tho inspection of the gauges has been in charge of Mr. L. P. Butler, assistant engincer, who has made three complete tours of inspection between the mouth and Sioux City during the year, one in September, 1893, one in November-December, 1893, and one in May-June, 1891; in addition to the work connected directly with the gauges he has made measurements of two bridges, completed during the year, conducted two special surveys, and aided in the gathering of commercial statistics.
The gauges at the present time are all in good condition, and only two entire renewals-at Dewitt, Mo., and Brownville, Nebr., -were necessary during the year.
A new permanent gauge was established' March 13, 1894, on Bellefontaine bridge. All the other gauges have been kept in good repair at slight expense.
Level connections between the gauge bench marks and those of the precise level lines having been completed, the graduations on all the gauges were made to read preciso level elevations above the St. Louis directris during the November-December inspection.
The pilot bulletin service for 1893 was discontinued on November 30, except for the Kansas City station, where it was made continuous at the request of local steamboat owners.
The service for 1894 was resumed on March 16 at the permanent gange stations between St. Charles and Kansas City, and on April 16 an adıitional bulletin was displayed on tho new Bellefontaine bridge, for which two of the larger size of frames had been provided. A slight change was made in the design of the bulletin frames for the Bellefontaine bridge at the instance of Mr. George S. Morison, chief engineer, which better adapted them for attachment to the bridge.
During the year 1893 the bulletins read from a stage 5.1 feet below a mean stage of the navigable low waters at each station, this stage having been taken in order that the Missouri River Commission bulletin readings should agreo with the daily published records of the Weather Burean at Kansas City. After the ganges were changed to read precise level elevations it was found that the equating number at Kansas City reqnired a change to 5 feet, and accordingly all the bulletins except at Randolph bridge now read from a zero which is 5 feet below a mean of observed navigable low water, as near as the data at hand allows the mean to be determined.
The exception noted at Randolph bridge appeared to be necessary, as its bulletin record of the year 1893 would sometimes show a higher stage on the same day than at Kansas City, 4 miles above; this may be accounted for by the change in slope between the two stations resulting from works of channel rectification and by an insufficient number of subsequent low-water gange heights.
The pilot bulletins are now exhibiting one daily reading in accorılance with the 6 a. m. stage from zeros as follows:
The zero elevation of the Weather Bureau gauge at Hermann is at present 71.23; but this value only holds good up to the 13-foot mark, above which the gauge
is wrongly graduated, each foot recorded being actually equal to about 0.876.
According to the rule adopted by the Commission the Hermann gauge shonld read from a zero of 68.35. The zero of this gauge has not been kept constant, having been as low as 67.34 previous to 1886, when it was changed to its present elevation
In connection with the determination of the mean navigable low waters, some study has been made, since the precise levels have been available, in an endeavor to trace a law connecting length of river with mean gauge heights.
The investigation has not yet been completed, but it has been carried far enough to show that, using the average distances above the mouth as measured on the lowwater channel lines from the maps of 1878–79 and 1890 as abscissa (3), the height of the mean navigable low water in that portion of the river from a point above tho mouth of Osage River to Rulo, Nebr., may be determined closely by the equation of the straight line y=0.812 x—7. The mean high water, for the same portion of the river may be approximately expressed by a similar formula of y=0.812 x +7.4 at all the stations except where there are large tributary streams, at which points a further addition of about 2.7 feet becomes necessary to the gauge heights.
On the portion of the river above Rulo no formula appears to be applicable, and on the lower portion the slope appears to increase and the formula changes. The gauge stations are quite far apart on these portions of the river, and perhaps with more data further study may reveal a practical result to an investigation which at present is only in a preliminary stage.
The bulletins, in addition to showing the daily stage of the river, also serve to give the available heights under bridges for passing steamboats, and cards explanatory of the service with a table for ascertaining this height from the bulletin reading have been issued to all steamboatmen interested.
The results of the precise levels have shown that all the stages published by the Missouri River Commission are more or less in error. These published stages are comprised in two pamphlets; one issued in 1886, entitled “Stages of the Missouri River from St. Charles to Fort Pierre, Dak., between 1872 and 1885," which was also published as Appendix A 6 of the annual report of the Missouri River Commission for the year ending June 30, 1886, and one pamphlet issued in 1890, entitled “Stages of the Missouri River from St. Charles, Mo., to Sioux City, Iowa, 1886 to 1889, both inclusive.”
The following table gives the correction to be applied algebraically to each of the published records to reduce them to the precise level elevations:
First Second pamphlet, pamphlet, 1872-1885. 1886-1889.
-0.144 -0.153 ---0.137 --0.132 -0.123 - 0.321 -0.319
+0.703 +0.495 +1. 270 +1. 295
* To August 26, 1889.
The manuscript of a third pamphlet in the series of Missouri River stages, embracing the four years 1890 to 1893 inclusive, is now ready for the printer. No change bas been made from the methods heretofore adopted for the perinanent preservation of the gauge records, as described in last year's report. Very respectfully, your obedient servant,
A. H. BLAISDELL,
APPENDIX A 5.
REPORT ON RESULTS OF ROCK BORINGS IX MISSOURI RIVER VALLEY.
OFFICE Missouri River COMMISSION,
St. Louis, Mo., June 30, 1894. SIR: I have the honor to hand you herewith a report on the results of rock borings in the Missouri River Valley. The placing on record of these results was inaugurated by my predecessor, an a detailed account of them may be found in the reports of the secretaries of the Commission. (Sec report of Chief of Engineers for 1890, p. 3375, and for 1892, p. 3261.)
Three additional sections of the valley have been collected during the past year as follows:
A section showing the depth at which a suitable stable foundation was struck on which to base the piers of the new Leavenworth bridge; two sections of a proposed new bridge at Jefferson City, Mo.; and an approximate section in the vicinity of St. Charles, Mo., on a site of a proposed bridge.
Each locality is accompanied by a map showing the location and number of borings taken.
The drawings show the results obtained quite as fully as any extended description would do, and similar conventional signs in addition to descriptive print havo been used as in former reports. Very respectfully, your obedient servant,
James F. MCINDOE,
President Missouri Rirer Commission.