also decide as to the proper location of the piers in accordance with the approved plans and be satisfied that the height of the bridge is right. Your letter of instructions of March 29, 1887, and all the papers which accompanied it, are returned herewith. The maps are sent in a separate package by mail. Respectfully submitted. CHIEF OF ENGINEERS, U. S. A. WM. P. CRAIGHILL, Colonel of Engineers. WM. E. MERRILL, Major of Engineers. LETTER OF COLONEL WM. P. CRAIGHILL, CORPS OF ENGINEERS. UNITED STATES ENGINEER OFFICE, Baltimore, Md., April 16, 1887. GENERAL: In sending forward to-day in a separate package the report of the Board of Engineers appointed to consider the subject of the bridge proposed to be erected near Point Pleasant over the Great Kanawha River, I have the honor to make a suggestion, which seems important. Referring to the second section of the law of March 3, 1887, I recom mend that such supervision be exercised by the officer in charge of the improvement of the Great Kanawha River as may be necessary to prevent the use of "insufficient foundations" for the piers and consequent "riprap or other outside protection," and to require that "all cofferdams or other temporary works be removed by the owners of the bridge before it be opened to traffic." Very respectfully, your obedient servant, To the CHIEF OF ENGINEERS, U. S. A. WM. P. CRAIGHILL, LETTER TO COLONEL WM. P. CRAIGHILL, CORPS OF ENGINEERS. OFFICE OF THE CHIEF OF ENGINEERS, UNITED STATES ARMY, Washington, D. C., June 17, 1887. SIR Referring to the report of the Board of Engineers of April 15, and your letter of April 16, 1887, respecting bridge to be built by the Ohio River Railroad Company across the Great Kanawha River at Point Pleasant, W. Va., I am directed to inform you that the plans and location recommended by the Board have received the approval of the Acting Secretary of War, upon the express conditions following: (1) That the level of low water from which, as required by the act aforesaid, the height of the bridge is to be measured, and the proper location of the piers in accordance with the plans hereby approved, shall be determined by the officer in charge of the improvement of the Great Kanawha River. ENG 88-154 (2) That such supervision of the construction of the proposed bridge be exercised by the officer in charge of the improvement of the Great Kanawha River as shall be necessary to prevent the use of insufficient foundation for the piers and consequent riprap or other outside protection, and to require that all coffer-dams and other temporary works be removed by the owners of the bridge before it is opened to traffic. You will therefore please exercise such supervision of the proposed bridge as may be necessary to determine that the conditions imposed by the War Department are faithfully observed. By command of the Acting Chief of Engineers. Very respectfully, your obedient servant, Col. Wм. P. CRAIGHILL, JAS. C. POST, Major of Engineers. Corps of Engineers. W W 9. BRIDGE ACROSS THE WEST CHANNEL OF THE DETROIT RIVER, TO CONNECT BELLE ISLE PARK WITH THE MAINLAND, AUTHORIZED BY ACT OF CONGRESS APPROVED JULY 20, 1886. OFFICE BOARD OF PUBLIC WORKS, Detroit, April 15, 1887. SIR: The city of Detroit having been authorized by act of Congress approved July 20, 1886, to construct a bridge across the West Channel of the Detroit River, to connect Belle Isle with the mainland, the board of public works caused the necessary plans and specifications therefor to be prepared, and as required by said act forward the same to you for approval. As this is a matter of importance to the people of the city of Detroit, the board of public works respectfully request that you give the same your earliest attention. Respectfully referred to Lieut. Col. O. M. Poe, Corps of Engineers, for examination and report as to whether the accompanying plans, etc., of the proposed bridge are in conformity with the requirements of the act of July 20, 1886 (for copy of act see page 37 of laws affecting the Corps of Engineers, Forty-ninth Congress, first session). In this connection a copy of the rule of the War Department "to be observed when application is made pursuant to an act of Congress for approval by the Secretary of War of plans for a bridge," etc., is herewith, which it is requested may be furnished the bridge authorities for their information and guidance; the drawings and papers contemplated therein to be furnished in duplicate and duly authenticated. By command of Brigadier-General Duane. JOHN G. PARKE, [Second indorsement.] UNITED STATES ENGINEER OFFICE, Detroit, May 18, 1887. Respectfully returned to the office of the Chief of Engineers with report of this date. Respectfully returned to the Secretary of War, through the acting Judge-Advocate-General, U. S. Army, inviting attention to the accompanying report of Lieut. Col. O. M. Poe, Corps of Engineers, dated the 18th instant, from which it will appear that he has given the subject full and careful consideration, and has reached the conclusion that the plans and location of the bridge satisfy the requirements of the act of July 20, 1886, and may therefore be approved. His views are concurred in by this office. J. C. DUANE, Brig. Gen., Chief of Engineers. [Fourth indorsement.] WAR DEPARTMENT, JUDGE-ADVOCATE GENERAL'S OFFICE, Washington, D. C., June 1, 1887. Respectfully returned to the Secretary of War, with formal instrument for his approval (prepared in duplicate) of the design and drawing and map of location of the bridge across the west channel of the Detroit River, to connect Belle Isle Park with the mainland. G. NORMAN LIEBER, Acting Judge-Advocate-General. [Fifth indorsement.] WAR DEPARTMENT, Respectfully returned to the Chief of Engineers for file in his office, one copy of the within instrument having been sent to Mr. John Camp bell, Secretary board of public works, Detroit. By order of the acting Secretary of War. REPORT OF LIEUTENANT-COLONEL O. M. POE, CORPS OF ENGINEERS UNITED STATES ENGINEER OFFICE, Detroit, Mich., May 18, 1887. SIR: In compliance with indorsement, dated office of the Chief of Engineers, April 21, 1887, on a communication of April 15, 1887, from the board of public works of the city of Detroit, Mich. (by John Campbell, secretary), submitting to the Secretary of War for approval, plans and specifications for a bridge over the west channel of Detroit River, to connect Belle Isle with the mainland, under act of Congress approved July 20, 1886, directing me to examine and report "whether the accompanying plans, etc., of the proposed bridge are in conformity with the requirements" of said act, and transmitting "a copy of the rule of the War Department 'to be observed when application is made pursuant to an act of Congress for approval by the Secretary of War of plans for a bridge,'" with instructions to furnish it to "the bridge authorities for their information and guidance,” I have the honor to submit the following, viz: The papers referred to me were received on the 24th of April and the copy of the rule of the War Department was transmitted to the board of public works on the same day. The municipal government had not, at that time, formally accepted the conditions of the act of July 20, 1886, but the necessary action was then taken, and a certified copy thereof (in duplicate) is herewith transmitted. The plans and specifications, with the action of the municipal authorities thereto attached, assigning charge of the work to the Board of Public Works (all in duplicate and duly attested) were furnished and are herewith transmitted; also a copy in duplicate of the charter of the city of Detroit. An examination of the plans and specifications for the proposed bridge reveals the following provisions to meet the requirements of the act: 1. Location.-Section 2 of the act requires that the bridge "shall be so located and constructed that the channel of said Detroit River shall not be unreasonably obstructed." The location proposed is from the river terminus of the so-called Boulevard to a point about 1,000 feet above the lower end of Belle Isle, the axis of the bridge to make an angle of about 76 degrees with the direction of the channel. The object of this appears to be to make the bridge an exact prolongation of the Boulevard, as well as to get the shortest bridge and the most convenient landing on Belle Isle. Ordinarily a bridge at right angles with the channel would occupy the shortest line, but in this case the shores on either side of the proposed line fall away from the channel in such manner that a bridge at right angles with it would be a little longer than in the position pro posed. The departure from a line at right angles with the channel is so slight (only 14 degrees) that I do not consider it a matter of much consequence; yet, in an engineering point of view, it would doubtless be better not to make any departure at all. If it be built on the inclined line there will be a slightly increased chance of deposits below the southern (or island) half of the bridge, but should such occur they will be in a locality which has never been used for general navigation, because such channel as exists there is too crooked for safe navigation, whilst the other channels are perfectly safe and easy. The difference in cost between a bridge located as proposed and one built on the other line would be something against the latter, and its southern (or island) terminus would be less convenient. The effect of a bridge on the proposed line in prolongation of a fine street, such as it is expected the boulevard will be, would certainly be more impressive and pleasing to the eye than if built with a change of direction, a fact which should be taken into account in this connection. Upon the whole, all questions considered, I think the arguments in favor of building the bridge on the proposed line outweigh those in favor of a line at right angles with the channel, and am of opinion that so located and constructed it will not unreasonably obstruct the channel of the river. I therefore recommend that the proposed location be approved. 2. Spans.-The second section of the act requires that the draw or pivot span shall be so constructed as to leave a clear opening of not less than 125 feet on each side of the pivot pier, and that the pivot pier shall be located over the channel of Detroit River in such manner that one or both of the openings of said draw or pivot span can be conveniently and safely reached and passed by boats navigating the ordinary channel. The pivot span proposed is 318 feet long, with a clear opening of 125 feet on each side of a pivot pier, located in the main channel in such manner that it may be conveniently reached and passed on either side of said pivot pier. The requirements of the act are therefore complied with in these respects. The act does not prescribe the length to be given the fixed spans. The specifications and drawings of the proposed bridge indicate 11 metal spans, measuring 156 feet each from centers of masonry. This length of span gives a clear water-way of about 149 feet between adjacent masonry piers, and, in my opinion, is sufficient. The spans might have been designed for a sufficient width to have rendered necessary at least one pier less, probably at no considerably greater cost, and I think it would have been better, but do not raise this point as a serious objection to the span proposed. 3. Approaches.-The plans and specifications show approaches of timber pile-work, the northern one (next the city) being 497 feet long, and the other being 600 feet. Although in these localities the action of ice is much less destructive than in the channel, yet it is likely to be sufficiently so to render their early reconstruction necessary. However, as proposed they are not likely to injuriously affect the channel, and may be approved. 4. Height at which the bridge shall be constructed.-Section 3 of the act provides "that the height at which said bridge shall be constructed above the surface of the river shall be such as may be approved by the Secretary of War." The specifications place the top of the bridge floor at a height of 22 feet above ordinary water level. This fixes the top of the piers at a height of 20 feet above the same level. The variation in the water level of Detroit River is comparatively slight, seldom amounting in any one year to as much as 2 feet. In a long series of years it might amount to as much as 6 feet, that is to say, 3 feet above or below mean level, consequently the height seems to be sufficient for all practical purposes. 5. Operating draw-span.-Section 4 of the act requires that all draw or pivot spans shall be operated by steam or other reliable mechanical power. The plans and specifications provide for steam-power, with alternative hand-power. The whole arrangement is well designed, and in my opinion may be approved. 6. Position of piers with reference to current.-It is required by section 5 of the act that the "piers upon which said bridge is built shall be parallel with the current of the river." The specifications appear to be silent as to the direction which the piers shall occupy with reference to the current, but refer to the drawings which accompany and form part of the specifications. (Item 13, page 2.) The drawings show all piers, abutments, and trestles parallel to the current, thus making the bridge askew with reference to them. This seems to be sufficient to secure the proper position for these por |