During the season of navigation of 1867, only thirty times did the wind blow from the east hard enough to make a sea at the mouth of the river, and of these thirty storms only twelve lasted during a day, so that, as a rule, vessels could load and unload at piers built out into the bay. I inclose herewith a "notice to masters of vessels," published by the Alpena Harbor Improvement Company, in which are stated the tonnage dues, &c., to be collected from all vessels drawing over 4 feet of water. Before any improvement should be made by the United States some arrangement should be made with reference to the rights and claims of the company. If it should be deemed necessary to improve this harbor I would propose the carrying out of the north pier 803 feet, and filling up the gap in the south pier, and a pier-head crib at the end of it. The piers to consist of crib-work, 20 feet wide, except the pier-head, which will be 32 feet wide. The proposed improvements are shown in red on accompanying tracing. The following would be the probable cost of the work: For 88,962 cubic feet pine timber, at 14 cents per foot.... $12, 454 75 For 88,9625 cubic feet pine timber framing, at 15 cents per foot.. For 2,025 cords of stone, at $9 per cord. For 110,100 pounds iron drift-bolts, at 4 cents per pound .. Add 10 per cent. for superintendence and contingencies.... 13,344 37 18, 225 00 4, 404 00 204 88 48, 633 00 4,863 30 53, 496 30 This estimate may be increased for dredging. No estimate for dredging is now made, as it is hoped that when the piers are carried out the shallow places alongside of the piers will be scoured out by the current of the river. Alpena is the collection district of Port Huron; nearest light-house is on Thunder Bay Island. Report of the exports from the port of Alpena, Alpena County, Michigan, as shown by the books in the custom-house office at said port, commencing May 1, 1870, ending September 30, 1870. I have the honor to be, very respectfully, your obedient servant, F. U. FARQUHAR, Captain Corps of Engineers, U. S. A. Brigadier General A. A. HUMPHREYS, Chief of Engineers, U. S. A., Washington, D. C. B 13. UNITED STATES ENGINEER OFFICE, Milwaukee, Wisconsin, November 11, 1870. GENERAL: I have the honor to acknowledge the receipt of letter dated Office of the Chief of Engineers, Washington, D. C., September 20, 1870, directing me to make such an examination or survey (if necessary) of Mackinaw City, Michigan, as would enable me to make a project and probable estimate of cost of a breakwater, or whatever other works that may be required, to make a harbor of refuge in the vicinity of Mackinaw City. I would respectfully report that I have made a careful examination of the accurate maps furnished by the lake survey, which furnish sufficient data in this case for any required estimates. Mackinaw City is situated at the most northerly point of the southern peninsula of the State of Michigan, and is near the west end of the Straits of Mackinaw. At present the city consists of a few houses, the local business consisting, for the most part, of supplying passing vessels with wood and shipping the same. For the predicted (by the owner of the land thereabouts) future, I refer you to the accompanying memoir and maps. At present there is not local importance enough to justify any expenditure of public funds in building a harbor of any kind. By an examination of the accompanying general map of the Straits of Mackinaw, it will be seen that there is not the slightest necessity of a harbor of refuge at this point. A vessel can find a harbor of refuge from any storm in one of the many harbors furnished by nature within a few miles of Mackinaw City, from a northeast storm, either behind Bois Blanc Island or McGulpin's Point; from a southeast gale, on the west side of Mackinaw City or McGulpin's Point; from westerly gales, just east of Mackinaw City; and from northerly storms, behind Bois Blanc Island. Indeed, the Straits of Mackinaw is abundantly provided with refuges for vessels in stress of weather, and if vessels cannot make their natural harbors, much less could they find their way behind a breakwater. In addition, there is along the south coast of the straits excellent anchorage ground. From inquiry, I have learned that the principal disasters to vessels in this locality have happened during foggy weather, or during gales accompanied by snow-storms. At present there is a crib-dock or pier constructed at Mackinaw City on the east side. This is shown on the owner's map, which is inclosed. On the same map is shown a rough delineation of the proposed or desired breakwater, as the owner of the land thinks is necessary Three miles of breakwater is proposed. This breakwater should be 35 feet wide and about 40 feet high, and would probably cost $3,369,875. Should the local importance of Mackinaw City ever justify the building of breakwaters in order to protect shipping lying there, they should be built in the bay to the east of the point, be far enough from shore, to allow of vessels "coming to " behind them, and should be placed so as to obstruct as little as possible the littoral currents. I have sketched on the accompanying tracing the place for such breakwater. It would be composed of two arms, each 2,000 feet long, 35 feet wide, and averaging about 30 feet high. This work would cost about $761,333 76. The items being as follows: 793,680 linear feet pine timber, (furnished, framed, bolted, and cribs placed,) at 40 cents per foot 1,374,240 pounds of iron bolts, at 4 cents per pound... 26,640 cords of stone, at $12 per cord For contingencies, add 10 per cent.... Total ... The estimate for timber may seem high, but it must be considered that the re-handling of much stone, and great inconveniences from the remoteness of the place, will make labor expensive. After the proposed system of light-houses are built, there can be no necessity for any artificial harbors in the straits of Mackinaw, as far as the general commerce of the lakes is concerned. I have the honor to be, very respectfully, your obedient servant, Captain Corps of Engineers United States Army. Brigadier General A. A. HUMPHREYS, Chief of Engineers United States Army, Washington, D. C. APPENDIX C 1. Report of operations at the improvement of St. Mary's Falls Canal and St. Mary's River for the fiscal year ending June 30, 1871. Though the subject of awarding the contract for the removal of boulders from the St. Mary's River, and of the submission and approval of a project for improving the canal, was briefly referred to in my last annual report dated October 14, 1870, I include herein, in order to make this report complete, a history of the improvements from the commencement of the fiscal year. An act of Congress approved July 11, 1870, appropriated the sum of $150,000 for the improvement of the St. Mary's Falls Canal and St. Mary's River, notice of which was received from the Chief of Engineers, under date of the 18th of July, 1870, with instructions to prepare and submit a project of operations thereunder. In partial compliance therewith I submitted a report, with form of advertisement inviting proposals for the removal of boulders endangering the navigation of the river St. Mary's, and for improving the west channel of East Neebish Rapids, St. Mary's River, but subsequently receiving assurances that the object of the appropriation was to furnish the means of enlarging the prism of the canal above the locks, it was suggested to the Chief of Engineers, on the 11th of August, 1870, that if the case was so understood by him to disapprove the project submitted; recommending at the same time that the work of making a prism of given dimensions and character, with a view to its connection with a new channel and locks alongside those now in use, be let by contract in the usual manner. Receiving instructions from the Chief of Engineers directing that the project for operations upon the west channel of the East Neebish Rapids be deferred, and the advertisement for the removal of the boulder rocks in the St. Mary's River be published as proposed, the publication of the advertisements was made accordingly, and the proposals offered opened on the 9th of September. The bid of W. W. and E. T. Williams to do the work for $4,800, being the lowest, was accepted, and the contract awarded them for the execution of the work. By the terms of the contract the contractors were to furnish all appliances and do all the work of removing obstructions in accordance with specifications. The work to be commenced on or before the 1st day of October, and completed on or before the 1st day of December, 1870. No accurate surveys having been made at any of the localities specified, except at the point near the head of Rains Island, it was found at some points that the work required to effect the desired improvements largely exceeded the amount anticipated. The first four obstructions consisted of boulders and earth, and were removed by dredging. The fifth was a ledge of limestone rock lying in its natural bed, and was blasted and the pieces removed by a diver. Operations by the contractors were commenced promptly at the three localities below the canal, and on the 15th of October an inspection of the work at the last two points specified revealed the fact that the least water on the area dredged near the head of Rains Island was 134 feet, and on the obstruction near the lower end of the island, 16 feet and 2 inches. Two days subsequently a further inspection of the work, two and one-fourth miles below the canal, showed a least depth of 16 feet; the water being in each case a few inches lower than in September. These results being reported to me I directed the resumption of the work at the point near the head of Rains Island. This shoal was found to be of larger extent than had been supposed, and much more work was finally done than had been contemplated when the contract was executed. A further inspection of this locality was made November 23, (the dredge having been employed there nearly two weeks after the receipt of my order directing the resumption of work,) resulting in the acceptance of the work. The two localities designated above the canal were found to be projecting points of the same shoal, and of much larger extent than that supposed. The work at these points was inspected and accepted; the first on the 9th and the last on the 27th of November, and the contract, therefore, completed and closed, and the balance due thereon paid to the contractors. The amount of dredging required greatly exceeded all the estimates. The contractors performed more than double the work anticipated, and yet the entire navigation was but little improved; though what was accomplished was directly toward that end. This was due to the fact that the obstructions did not consist of detached boulders, as originally represented, and upon which a previous report and estimate were predicated, but of extensive shoals composed of boulders. In accordance with instructions from the Chief of Engineers, a project was submitted to him on the 1st of September, 1870, with a view to the construction of new lockage alongside that existing, and the excavation of the prism of the canal to a certain indicated width and depth. This was approved in general, but subsequently modified specifications, with a report on the subject, were also submitted for approval, for so much of the new work as might be accomplished under the appropriation available, involving the enlargement of the prism, as well as the construction of a revetment wall and guard-gates. This modified project was also approved, and after due advertisement a contract was entered into, October 20, 1870, with Messrs. Barker, Williams, and Bangs, the lowest bidders, for the prosecution of the work. The contract providing for the enlargement of the prism of the canal by excavation of the sides and bottom, so that when the revetting walls should be built the dimensions of the water-way above the new position of the guard-gates would be as follows: Width at coping of revetting walls.. Width at surface of water, 5 feet below coping. Width at 20 feet in depth.. Depth of bottom along axis of canal, and for 36 feet 9 inches on each side thereof, measured from level of coping. Depth at 46 feet 9 inches on each side of the axis, measured from level of coping. Slope of sides after wall is built, or of excavation, where it is in rock for 18 feet in depth below coping, 3 inches to 1 foot. Slope of sides from above-named limit to bottom of canal, 60 inches to 1 foot. The contract also embraced the construction of a revetment wall, and new guard-gates, the latter upon the plan of the old ones and to be placed in position at least 700 feet nearer the head of the canal. The contract further provided that the contractors should receive as full compensation for the work performed, upon approximate monthly estimates, the following rates, viz: For rock excavation. For gravel excavation. For revetting wall.. For rebuilding guard-gates, $15,000. $3 50 per cubic yard. 80 cents per cubic yard. 15 cents per cubic foot. All measurements to be made in situ, and the work to be commenced on or before the 20th of October, 1870, and completed on or before the 1st day of July, 1871. The plan of operations for the winter involved the removal of the guard-gate to the new position; the deepening of the water-way, the removal of the side slopes, and the revetment of the sides of the cut with a wall of stone; the work to be commenced at the upper entrance to the canal and continued downward until the appropriation should be exhausted. For nearly the whole distance from the inner end of the south pier to the guard-gates the rock appears above the water's surface, and from the inner end of the south pier westward appears to have a slope to the westward of about 1 to 60. The rock is Potsdam sandstone, red and gray in alternating strata, and of very variable hardness, some so soft as to be removed easily with a pick and shovel. The revetting wall was to be founded on the first stratum of suitable rock found in the sides of the excavation. Below the base of the wall the face of the rock was to be dressed off to leave a smooth and uniform surface. Contrary to expectation it was discovered that the excavation would furnish but little, if any, stone fit for use in constructing a revetting wall. It was believed that a sufficient quantity would be thus obtained to at least bring the walls to the surface of the water, and owing to the lateness of the season nothing else could have been relied upon. Stone could not have been quarried at Sandusky or elsewhere and carried to the canal before the close of navigation. Under these circumstances it was necessary to modify the previously adopted plan of operations by |