Upon a general demand for more detailed information for close navigation in the Apostle Island Channels, Lake Superior, the project of constructing three charts of the Apostle Islands and vicinity in colors was approved by the Department, and Chart No. 1, covering all islands (except the south portion of Madeline Island), was commenced on a scale of 1:40,000, to be reduced by photolithography and published to scale of 1:50,000. Chart No. 2, covering Chaquamegon Bay and adjoining portions of south coast of Lake Superior, will be prepared in the same manner as Chart No. 1. Upon completion of these two charts, they can readily be combined by photolithography into one single coast chart to scale of 1:80,000, for general navigation. The substitution of colored lithographed charts for the finely engraved ones heretofore used is highly gratifying to vessel masters, as the distinction between navigable and dangerous water areas is plainly apparent at a glance, and the distortion of copper plate prints by which errors in scaled distances result is entirely obviated. It is, therefore, desirable that this method be extended to the other charts issued from this office. as fast as we find it practicable to do so. Surveys. Besides limited surveys made in connection with the correction of old charts a hydrographic survey of Potagannissing Bay, St. Marys River, was in progress and nearly completed at the close of the year. This work was essential for properly completing the resurvey of the St. Marys River and providing data for new chart No. 1, the publication of which has been delayed for this purpose. Water levels.-The elevation of the water surface of Lake Huron has been recorded, as heretofore, by tridaily readings of the gauge at Sand Beach Harbor of Refuge, and similar record has been kept respecting the upper St. Marys River by gauge at the head of the Government Canal at Sault Ste. Marie, Mich. The following table shows the monthly means for the year as derived from these records: Monthly means of water level for Sand Beach and Sault Ste. Marie, expressed in feet below the plane of reference adopted in 1876. Stations. Sand Beach.. July. Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May. June. 3.96 4. 07 4.26 4.57 4.65 4.84 5. 10 5.24 5.09 4.92 4.38 3.99 2.67 2.54 2.69 2.86 2.95 3.43 3.58 3.69 3.70 2.84 2.39 The accompanying plats illustrate the varying stages of water as shown by like records for the last four years. Investigation of lake levels.-A comprehensive project for this most important study was presented in my report of January 15, 1898, and a less extensive one, better adapted to the limited means then likely to be available, was submitted March 28, 1898. These reports are printed in the Report of the Chief of Engineers for 1898, pages 3774 to 3776. The later project was duly approved May 21, and operations during the last fiscal year have been in accordance with it, but limited in extent to conform to the comparatively small amount of money available and the necessity of considerable expenditure therefrom for obtaining the necessary outfit, including a full current meter plant, self-registering water gauges specially designed for the work, precise leveling equip ment, steamer, small boats, and other minor items. Field work was planned and carried on with the special object of first doing that part which related especially to the study assigned by Congress to the Deep Waterways Commission, and the cost of this part of the work was paid jointly by that commission and this office. The principal fea tures of it were measurements of flow and slope of parts of the St. Lawrence, Niagara, St. Clair, and Detroit rivers, including precise leveling operations through a distance of 126 miles on the St. Lawrence, from Cape Vincent at the outlet from Lake Ontario to St. Regis, and over a line 100 miles long from Gibraltar to Fort Gratiot, which provides for an accurate determination of the fall from Lake Huron to Lake Erie at all varying stages of water in these lakes, together with like determination of slope from point to point in the waterway connecting them. Some measurements of discharge were also made in the St. Marys River. Self-registering water gauges were established as fast as they could be supplied by the maker and 8 were in service at the close of the fiscal year, viz, 2 in Niagara River, 1 in Detroit River, 4 between foot of Lake Huron and Lake St. Clair, and 1 at Mackinaw City, Straits of Mackinac. Seven more remain to be placed to complete the series of fifteen as now contemplated. The reduction of data supplied by field operations has been carried forward as time and opportunity afforded, but it has not yet reached such a point as to justify publication at present. One unexpected feature of special interest and impor tance may be referred to briefly as a result of investigations so far made at the head of the St. Clair River, viz, a marked deepening since the survey of 1867 in that reach of the river which is one of the controlling factors in the outflow of Lake Huron. Steps are now being taken to make a most minute investigation of this locality and thereby obtain data that will be of vital importance in the study of the Lake-MichiganHuron level. Details of operations outlined in the foregoing paragraph are contained in the subreport submitted herewith, being that prepared by Assistant Engineer E. E. Haskell, who was charged with their supervision and direction. It has not been possible with the limited appropriations made during the last ten years to keep our lake survey charts up to the same standard of excellence that they possessed fifteen years ago; they do not correctly show the conditions now existing, and they are by no means so satisfactory to the navigator as they were fifteen years ago. Much more extended surveys and examinations than we have been able to make are necessary for developing natural and artificial changes that are constantly going on, in order that the charts may be brought up to date and kept so. But to do this at a reasonable rate of progress, it is absolutely essential that the annual appropriations of recent years be doubled for a few years to come, and for that reason the appropriation for this purpose should be at least $50,000 for the year ending June 30, 1901. This is certainly a small sum, considering the vast commercial interests dependent upon the accurate, up-to-date condition of these charts. But this work, important as we recognize it to be, must now be extended into a field of still greater importance for the time being, viz, the investigation of lake levels under the project inaugurated dur ing the last year, the immediate practical purpose of which is to devise the best means of regulating these levels, and of preserving or increas ing the navigable depth of natural and improved channels in the lakes and their connecting waters. Operations under this project are now dependent upon small allotments from two pertinent appropriations; but, if any reasonable progress is to be realized, it is essential that means be provided for continuing them on a much more extensive scale. The work is so intimately connected with the lake surveys, past and present, as to induce the suggestion that its further prosecution be in connection with appropriations for these surveys. It will be absolutely impossible to make anything like satisfactory progress in these investigations unless an expenditure of at least $100,000 be provided for during the year ending June 30, 1901. It is therefore recommended that the estimate for the year 1901 be made to include the two amounts specified in the foregoing paragraph, and that their appropriation be formulated as follows: For survey of Northern and Northwestern Lakes, including all expenses of correcting, extending, and issuing charts, and investigating lake levels with a view to their regulation, to be available until expended.................. Money statement. July 1, 1898, balance unexpended..... June 30, 1899, amount expended during fiscal year, including $36.90 paid by Treasury Department account Michigan Central Railroad Company. $150,000 $35, 699. 21 331.64 9,739. 50 18, 260.50 64, 030. 85 29, 429.86 July 1, 1899, balance unexpended.. July 1, 1899, balance available....... 34, 600.99 2, 541.91 132, 059.08 Dates and amounts of appropriations for survey of northern and northwestern lakes. In addition to this balance reported by Lieutenant-Colonel Lydecker, there remains of this appropriation unexpended the sum of $6,882.21. |