D. 15.-.Abstract of contracts entered into during the fiscal year ending June 30, 1871, for the improvement of harbors on Lake Erie, west of Dunkirk, New York. Andrew Spalding, Buffalo, Lewis J. Bennett, John Hand, Removing from main ship-channel through Maumee Bay, Lee & Dunbar, Erie, Pa. Buffalo, N. Y. Thomas Keeler, George M. Hugh W. Smith, Buffalo, Orville J. Jennings, Syra- Toledo Harbor, Ohio, 120,000 cubic yards, more or less, Removing from Sandusky Bay, Ohio, 25,000 cubic yards, Removing from the channel, between the piers of en- Removing from the channel over the inner bar, Erie Harbor, Pennsylvania, 60,000 cubic yards, more or less, of sand. Constructing, furnishing material, and putting in place 90 feet piering, at Conneaut Harbor, Ohio. Removing portion of wrecked north pier; constructing, furnishing material, and putting in place 120 feet piering at Erie Harbor, Pennsylvania. Respectfully submitted. D 16. Report upon the survey of the harbor of Port Clinton, Ohio, made in accordance with letter of instructions from the Chief of Engineers, dated Washington, D. C., July 23, 1870. The survey of this harbor was begun during the second week of November, and was continued at intervals, when the weather permitted, until near the closeo f that month, when the season became so cold and stormy as to prevent the soundings from being carried farther than the sketch indicates. Enongh was learned, however, of the character of the channel from the point where our labors terminated to its entrance into the lake, to enable us to form an estimate of the probable cost of attempting to improve it. For a mile from the extremity of the peninsula, lying on the northern side of the river's mouth, the channel runs nearly parallel with the shoreline in an easterly direction, its only protection lakeward being a bar of shitting sand, through which it finally enters the lake. Through this channel, which is quite crooked, only about six feet water can be carried at the stage of water given by the survey. If 8 feet depth could be given here the traders would be satisfied, for not more than 6 feet water can be carried down the Portage River from the lumber-mills above, which furnish the entire trade of this harbor. A channel 8 feet deep and of sufficient width to accommodate the small vessels running here could be made at no very great expense; but it would be useless to do this, without at the same time constructing a breakwater for the whole length of the bar above mentioned, to preserve the channel so deepened from being filled in by the action of the lake waves upon its exposed flank. Such a breakwater properly built would cost not less than $250,000. The only other alternative which presents itself, then, in order to make a good harbor here, is to break through this bar at some convenient point, and by the construction of an east and a west pier extending from the shore lakewards to the necessary depth, confine the waters of the river to the new opening, which would generally be kept open for the small vessels which alone make use of this harbor. This suggestion has been made before by General Cram, and I agree with him in the location of the proposed cut, but not in the direction of the piers nor their mode of construction. By an examination of the sketch herewith, it will be seen that opposite the outer extremity of the 6-foot river curve there seems to have been an effort made by the river-water to break through the bar. Here I would locate the new mouth, limited on the east by a pier running from 8 feet water nearly perpendicularly to the shore, and on the west by a pier starting at the same depth, and with two or three changes of direction, reaching the end of the peninsula at the mouth of the river. This would require about 4,500 feet of piering, which, from its position, could near the shore-line, be built much lighter than a breakwater parallel with the shore, though at the outer ends the ordinary thickness of pier-work for these waters should be maintained. The estimated cost of this I find to be $120,000. The sketch herewith gives the proposed position of these piers. I give below a statement of the amount of commerce of Port Clinton, for the eight months from April to December, 1869, since which time it has been steadily increasing: Clearances: Steamers, 319; sailing-vessels, 274; total, 593. Tonnage, 32,800. Average tonnage, 55. Average number of crew, between 4 and 5. Estimated value of cargoes, $332,000. The number of entries is not included, because the trade is all outward. One mile above the bridge the water shoals to 7 feet and continues so for three miles, then follows one mile of 8 feet water and eleven miles of 6 feet water, which carries us to the last mill on the navigable portion of the river. From Port Clinton to this point there are on the river bank six steam saw-mills, one large stave factory, and one shingle factory. Respectfully submitted. WALTER MCFARLAND, Major of Engineers. D 17. Report upon the survey of the mouth of Rocky River, Ohio, made in accordance with letter of instructions from the Chief of Engineers, dated Washington, D. C., July 23, 1870. The survey of this river was limited to that portion of it lying below the bridge over which the main road from Cleveland to the West passes, as no part above the bridge could be rendered available for the purposes of commerce. The survey was begun in the last week of October and was completed by the middle of November; although on account of the other duties required of my assistants, Irvin Camp, civil engineer, and David' Enright, civil engineer, the plotting of the field-work was not begun until the last week in December. The finished map was transmitted to the Chief of Engineers on the 20th of January, 1871. By examining that map, an outline tracing of which accompanies this report, it will be seen that in its passage from the bridge to Lake Erie, a distance of about 1,000 yards, the river divides into branches, which, after encompassing an upper and a lower island, unite again and enter Lake Erie between a high rocky bluff on the west and a low sandspit on the east. The eastern branch varies between 150 and 250 feet in width, and the western branch from 75 to 100 feet in width. The depth of water from the bridge to the head of the upper island, which on the sketch herewith is numbered 2, varies from 2 to 3 feet. Here, however, it begins to deepen slightly, and near the foot of island No. 2, 6 feet water is found. This depth, with four slight interruptions which are indicated on the sketch, is carried to the outer bar, where the water shoals again to nearly 4 feet. Soundings were taken over this whole area, from the bridge to the 13foot curve in the lake, at distances of 10 feet on lines averaging 100 feet apart, and borings to the rock substratum were also made at distances of 20 feet on liues averaging 200 feet apart. But one-half of these soundings and borings are plotted, every alternate one in each line having been omitted. The results attained show that the bottom consists of sand chiefly below which, at depths varying from 1 to 4 feet, rock is found. The character of this substratum is probably not different from tha of the rock forming the bluffs which border the river and the neighbor ing lake-shore, and which consists of thin strata of slaty material, s much broken with joints and fissures as to be easily separable. The fac that the auger frequently appeared to enter such joints seems to confirm this opinion; and I have been informed, furthermore, that this rock ha been dredged out here and there, without the aid of blasting, to a dept of 8 or 10 feet. The material so moved which had been dumped alon the shore of island No. 1, to prevent it from being washed away, I saw and it appeared to be of the same character as that composing th bluffs. To make this harbor available for commercial purposes, or as a ha bor of refuge, two things are essential, viz: a very large amount dredging, and the construction of an east pier, extending from the san spit at the mouth of the river to a point opposite the angle of the blu on the west side. At the stage of water given by the map, which may be taken as th lowest during the year, no vessel drawing over 4 feet could cross th outer bar as at present. After passing this, although the water deepen to 10 feet in the channel off the spit, not more than 6 feet can b carried up the western branch to near the middle of island No. 1, whil the passage into the eastern branch, which has about 6 feet water,: obstructed by a bar between the spit and the lower end of island No. on which there is but little over 4 feet water. My estimates I have limited to a channel-way 100 feet in width extending from the outside of the outer bar through both branches t the head of island No. 1, and from 6 to 12 feet in depth; and I give th estimated cost of doing the work on both suppositions, i. e., that blas ing may not or may be required, reckoning the price of dredging san at 30 cents per cubic yard; of dredging rock, without blasting, at 4 cents per cubic yard; of blasting, at $2 per cubic yard, and of dredgin rock after blasting, at the same price as sand, i. e., 30 cents per cub yard. To make the eastern branch 200 feet broad and 12 feet deep would require from $15,000 to $50,000 additional, according as it did not or did require blasting. The east pier proposed would be 500 feet long, and should be not less. than 18 feet in width, which, at $60 per lineal foot, would require $30,000 for its construction. The total amount, then, required to improve this harbor as herein explained would be The eastern branch might, however, be made 200 feet broad for the amount estimated as necessary in order to give a channel 100 feet broad up both branches. Respectfully submitted. WALTER MCFARLAND, Major of Engineers. UNITED STATES ENGINEER OFFICE, APPENDIX E 1. UNITED STATES ENGINEER OFFICE, Buffalo, New York, September 10, 1871. GENERAL: I have the honor to submit the following, my annual report, for the improvement of Dunkirk Harbor, for the fiscal year ending June 30, 1871: The re-enforcement of the west United States pier mentioned in my last annual report was begun, and notwithstanding constant hinderance and loss inflicted by weather, was completed during the working season of 1869, and was the only work in hand during that season. The work now stands in good condition; the method of re-enforcement has proved a complete success. The work was done by hired labor by means of material remaining on hand from previous work. The board of engineer officers convened at Dunkirk, New York, November 3, 1870, adopted a general plan for the further improvement of this harbor, which plan I was directed to carry into effect as far as the existing appropriation would avail. Preparations to this effect were made and work was commenced at the close of the fiscal year. The removal of the old outer breakwater, after many unavoidable delays, was completed July 12, 1871. Under the plan of the board of engineers the day-beacon will be built and about 200 feet of breakwater laid during the present working season, the work being done by contract with O. J. Jennings, of Syracuse, New York, under my letting of May 8, 1871, the iron material being purchased in open market, it having been found impracticable to contract for the same in time to complete the work this year. |