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of the records of the Department. We accompany this report also by other papers referred to in the body of it-seven in number-marked from A to G, inclusive. Yours, respectfully,

G. K. WARREN,

Major of Engineers and Brevet Major General, President of the Board. Brigadier General A. A. HUMPHREYS,

Chief of Engineers, U. S. A.

Report of the board of engineers convened by Special Orders No. 106, dated Headquarters Corps of Engineers, Washington, D. C., September 23, 1870, and ordered to examine and report upon the plan and location of a bridge to be erected across the Niagara River, at Buffalo, New York.

WASHINGTON, D. C., February 7, 1871. GENERAL: The board of engineers, constituted by Special Orders No. 106, dated Headquarters Corps of Engineers, September 29, 1870, (copy appended and marked A,) met at Buffalo, New York, October 3, 1870, and in obedience to that order proceeded to examine the plan and location of the international bridge in process of construction over the Niagara River, at Buffalo. The board having first examined the plans and papers furnished from the office of Chief of Engineers for its consideration, then proceeded to visit the bridge site in order to examine the piers in process of construction, and procure from the bridge company's officers the data necessary to enable it to make a full and complete report upon the subject.

All the information available at the time having been collected, it was found that it was insufficient; inasmuch as no observations had been made for the force and direction of the current at the bridge site, neither was the survey of Black Rock Harbor sufficiently extended and in detail to determine the proper position and dimensions of the draw at that harbor.

The law of the State of New York prescribes that the bridge shall "not materially impede the navigation;""shall be constructed in two draws, one across Black Rock Harbor, and the other across the main channel of the river;" and that "the 'draws of said bridge shall be of ample width to give free and unobstructed passage to all steamboats and other vessels navigating said river or Lake Erie."

The law of the United States further provides "that such bridge shall have at least two draws of not less than 160 feet in width in the clear between the piers, which shall be located at the points best calculated to accommodate the commerce of said river, and the piers of said bridge shall be parallel to the current of said river."

The plan of the bridge company proposed a bridge of nine spans from the Canada shore to Squaw Island, and four spans across Black Rock Harbor. Of the river spans the three nearest the Canada shore and the two nearest Squaw Island were to be 190 feet in the clear; the two adjoining the draw, of 240 feet each; and the draw-bridge, located nearly at the middle of the river, to be 354 feet long, swinging on a pivot-pier of 34 feet diameter, giving two clear passage-ways of 160 feet each.

The crossing of Black Rock Harbor was to be effected from Squaw Island, by first a draw-bridge of 184 feet, swinging on a pivot-pier of 34 feet diameter, giving two clear passage-ways of 75 feet each, then a span of 100 feet in the clear, then a span of 140 feet in the clear, reaching the abutment at the Black Rock shore. The dimensions of piers and specifications for the work are fully set forth in the MS. then before the board, and now herewith appended, and marked B.

In the light of the information then before the board, and their cursory examination of the bridge site, it appeared advisable to transfer the river draw from the location proposed by the bridge company to a point nearer Squaw Island, placing the pivotpier in 10-feet soundings, the shore end of the draw resting on an abutment built out from Squaw Island. It also appeared to the board that the Black Rock Harbor draw might be made of smaller span than required by the United States law, and still answer all the requirements of commerce, if the law could be so modified. It was observed that the bridge company's plan gave only 75 feet in the clear to each opening of the Black Rock Harbor draw, which did not satisfy the conditions of the law. AS that harbor was under the jurisdiction of the New York canal commissioners, it became Becessary to consult their wishes on the subject. In view, therefore, of these facts, and the lack of necessary information, the board resolved to adjourn temporarily, delegat-. ing to the junior member the duty of obtaining from the bridge company's officers the additional data necessary to enable it to come to a decision, and also directing him to request of the canal authorities of the State of New York a map of Black Rock Harbor showing the changes they proposed to make in that harbor, and the location and width of such a draw as would be in accord with their plans.

The board thus adjourning temporarily, submitted a preliminary report to the Chief of Engineers, a copy of which is herewith appended and marked C.

The duty delegated to the junior member was performed. Observations for force and direction of the current were made by the bridge company's officers, using weighted floats 12 feet in length, and the result platted for the use of the board.

A plan of Black Rock Harbor was also prepared and submitted by the bridge company's officers, and in answer to the inquiries made by the board, New York State Canal Commissioner John D. Fay sent the reply, (appended and marked D.) accompanied by a map of the harbor showing the bridge-crossing, together with improvements projected by the canal authorities. The information thus collected was laid before the board reconvened at Washington, D. C., January 28, 1871, in obedience to Special Orders No. 7, dated headquarters Corps of Engineers, Washington, D. C., January 17, 1871, a copy of which is herewith appended and marked E.

The board first took up the question of the Black Rock Harbor crossing, considering the letter of Canal Commissioner Fay, dated November 9, 1870, and the accompanying map. In reply to this letter the board suggested in a letter to him that, for a drawbridge over Black Rock Harbor, openings of 160 feet might be unnecessarily large, gave their reasons for this conclusion, and asked if the canal authorities of the State of New York would consent to a draw of less width, and if so, what width, and also suggested that the proposed new lock might be located to better advantage further up the harbor, about five hundred yards above the proposed bridge site.

In reply to this letter an answer (appended and marked F) was received, announcing 90 feet in the clear for each draw opening at Black Rock Harbor, as agreed upon by both the canal authorities and the bridge company, and that the proposed lock could be located to suit the circumstances of the case.

Having all the necessary data before it, the board proceeded to a careful consideration of the plan and location of the bridge, taking up first the subject of the portion crossing the river.

The board approves of the location of the bridge and its general plan, but respectfully recommends certain modifications in that plan which it will now proceed to discuss.

It appears by computation from the data furnished by the bridge company's officers that on the day when they observed the force and direction of the current the area of the natural section of the river at the bridge site was 41,106 square feet, the discharge per second at that time 245,296 cubic feet of water, at an average velocity of 5.96 feet per second. By comparison of the bridge company's plan with the same modified by locating the river draw near Squaw Island, as proposed by the board, it was found that the piers as located by the bridge company obstructed an area of 3,8153 square feet, kept back per second 25,2584 cubic feet of water, and would increase the average velocity of the current to 6.5 feet per second, whereas the piers and abutment, as located by the board, would obstruct an area of 3,497 square feet, keep back per second 19,069} cubic feet of water, and would increase the average velocity of the current to 6.37 feet per second. Thus it appears that there would be an increase of the mean velocity of the current by .54 feet per second by the bridge company's plan, while there would be an increase of only .41 feet per second by the same modified as proposed by the board. It was also found by computation from the same data, that were the draw located as proposed by the bridge company in the axis of the river, the current at that draw would run six miles an hour as against four miles an hour through the draw located as proposed by the board. It is therefore obvious that if the wants of commerce can be subserved by locating the draw near Squaw Island, as proposed by the board, it should be done, inasmuch as thereby the flow of water will be least obstructed, the mean velocity of the current the least increased by pier obstruction, and the velocity through the draw-spaces greatly diminished, thus affording greater facility for the passage of vessels. It appears to the board that the wants of commerce will best be subserved by this change, inasmuch as the draw, as located by the board in the lesser current, will accommodate vessels of the greatest draught at present navigating the great lakes. The location for the draw proposed by the board is indicated in red on the profile upon the bridge company's plan, as also the modifications in the position of the piers, and the extent of the abutments to be built out from Squaw Island to receive the shore end of the draw-bridge. The depth of water in the in-shore draw-space varies from 8 to 16 feet, and would accommodate vessels of light draught at any stage of water. The depth of water in the outer draw-space varies from 16 to 25 feet, and would accommodate vessels of the greatest draught at all stages of the river.

The Squaw Island abutment, built out about 150 feet into the river, would serve as a guide for vessels passing the draw, thereby facilitating their progress, and also definitely mark the wharf line, should the shore of Squaw Island be used for such purposes. In recommending this change of position of the draw, the board desires it to be distinctly understood that the draw-spaces should remain unchanged from the original plan, leaving two clear passage-ways of 160 feet each in width, and the piers retain the same dimensions as before proposed, varying only in height to suit the depth of water. The modification in the arrangement of the piers and draw of the river branch of the bridge, as described above, and indicated on the bridge company's

plan in red, is respectfully recommended as a substitute for the arrangement proposed by the company; and it may also be observed in this connection, that in conversation with the bridge company's officers the board have been led to understand that far from making any objection to the proposed change they gladly concur therein.

The saving in cost of construction is obvious upon comparing the two projects, to say nothing of the difficulty of building the pivot pier as proposed by the company in 41 feet of water running at the rate of six miles an hour.

As regards the crossing of Black Rock Harbor, it is proper to consider the conditions to be satisfied in locating a draw at that point.

It appears from observation of the site that at the present time the harbor and canal are there without division; that a portion of the water of the canal and harbor is used to feed mills just below the bridge site; that the result of the lack of division between the harbor and canal is that the deposit of silt in the harbor is encroaching upon the limits of the canal. It also appears from Canal Commissioner Fay's letters and map, that the New York canal authorities propose to remedy the above-mentioned evil by building a division wall between harbor and canal, affording access from the one to the other by means of a ship-lock to be placed at some point in the division wall. Vessels, therefore, ascending the river, and desiring to avoid the swift current between the bridge site and the river's head, can pass through the old ship-lock as heretofore, thence through the new lock into the lesser current of the canal and harbor, and thence to Lake Erie. In order to do this with convenience and safety, the draw-bridge over Black Rock Harbor must be of such dimensions and so placed with regard to the two locks as to admit of vessels passing without great deviation from a straight course. The letter of Canal Commissioner Fay, dated January 30, 1871, shows the agreement to which the canal and bridge authorities have come.

Inasmuch as the old lock will not accommodate vessels of greater beam than thirtysix feet, the board regards the draw, with openings of 90 feet each in the clear, as agreed upon by the canal and bridge authorities, as sufficient to satisfy the wants of commerce in the harbor, provided the new lock is properly located with reference to the bridge.

A larger opening is unnecessary, and rather liable to impede than facilitate the navigation and transit over the bridge, by the time lost in opening and closing. In order to have this location in harmony with the plans of the New York canal commissioners, the board recommends the Secretary of War to adopt such location of this draw as the New York canal commissioners may advise.

The recommendation of the board with regard to the modifications to the bridge in the main river are in accordance with the laws of the United States, and will require nothing but the approval of the Secretary of War.

In the opinion of the board, the width of openings in the draw at Black Rock Harbor are required by the United States laws to be 160 feet wide. The plan proposed by the bridge company allows of openings of only 75 feet, and the board has, on consultation with the New York canal commissioners, as beforesaid, recommended that they be made 90 feet wide. The board, therefore, suggests the following amendment to the existing law:

"Be it enacted, That the bridge across the Niagara River, near Buffalo, New York, authorized by the act approved June 30, 1870, shall be constructed with a pivot draw in the main river, giving two clear openings of 160 feet each, and across Black Rock Harbor, with a pivot draw, giving two clear openings of 90 feet each, subject, in all other respects, to the provisions contained in the act approved June 30, 1870."

With these conclusions the board respectfully submits the accompanying papers and plans, which have been under discussion before it during its deliberations, and will, at a future date, as soon as it can be prepared, submit, for the files of the office of the Chief of Engineers, a map embodying as much as possible of the information concerning the bridge, its site, and the river above and below the site, upon the basis of which the board has arrived at the conclusions herewith submitted.

We are, general, very respectfully, your obedient servants,

G. K. WARREN,

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APPENDIX F 1.

Annual report of Major J. H. Wilson, Corps of Engineers, for the fiscal year ending June 30, 1871.

REPORT OF OPERATIONS AT OLCOTT HARBOR, NEW YORK.

The opening of the year found the work in the following condition: The east pier was 438 feet long, and 20 wide, 319 feet being built to its full height, and the remainder incomplete.

The west pier was 518 feet long, 305 feet being 15 feet wide, and the remainder 20 feet wide; of this pier 501 feet was built to the full height, the rest being incomplete.

During the year there have been added to the east pier five cribs, each 30 feet long by 20 feet wide, and averaging 93 feet in depth. The superstructure has been extended and filled with stone for a length of 170 feet. The east pier is now 588 feet long.

There have been added to the west pier six cribs, each 30 feet long by 20 feet wide, averaging 10 feet in depth. The superstructure has been extended and filled with stone, for a length of 77 feet. The west pier is now 690 feet long.

During the winter 159,000 feet, board measure, of timber and plank, and 188 cords of stone, were purchased for work this season.

During the last season operations were carried on by hired labor, and the purchase of materials in the open market.

On the 12th of April, 1871, proposals were invited for labor and materials for this season's work, and on the 12th of May the contract was awarded Mr. J. D. Cooper, of Olcott. He commenced operations on June 5, and by the close of the fiscal year had succeeded in sinking three cribs, and completing the superstructure upon 200 lineal feet of the pier. The work is being pushed forward energetically.

During the present season, in addition to the work already completed, it is proposed to extend the east pier 140 feet, and the west pier 90 feet. To complete the project for the improvement of this harbor will require that the piers shall be extended until a depth of 12 feet is reached in the lake, and that a channel 150 feet wide between the piers, and 200 feet wide from the inner end of the piers to the bridge, shall be dredged. This will require the extension of each pier 180 feet in addition to the extension to be built this season, and the removal of about 57,000 cubie yards of material.

The amount required to complete the work will be $35,000.
Olcott is a port of entry in collection district of Niagara.

The nearest fort is Niagara, eighteen miles to the westward, and the nearest light is at the fort.

The amount of revenue collected during the fiscal year was $44 80 in currency, and $1,138 65 in gold.

The number of vessels entering and clearing was 32, with an aggregate tonnage of 1,042 tons. Amount expended during the year, $9,966 50; amount available July 1, 1871, $5,501 28; amount required for the fiscal year ending June 30, 1871, $35,000.

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Abstract of proposals for material and labor for pier-work at Olcott Harbor, New York,

States Army, May 12, 1871.

Opened by Major John M: Wilson, Corps of Engineers, United

Per pound.

Amount.

Per 100.

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* Awarded.

+ Informed as to manner of bidding and form of guarantee. Items not specified on abstract, the informalities being such as would require special classification. OSWEGO, NEW YORK, May 12, 1871.

Amount.

Total.

pails, 1,600

treenails.

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