Augusta as good as it now is below that point will require an expenditure of about ten thousand dollars. Protection of the Great Brewster island in the harbor of Boston, in charge of Colonel S. Thayer.-No operations have been undertaken since September, 1854, for want of funds. The work, which in its present unfinished state, falls short of accomplishing the object designed, and is moreover exposed to be severely injured by gales of wind, should be completed at once. An appropriation for this object is urgently recommended. Protection of Lovell's island and sea-wall on Deer island, Boston harbor, Massachusetts, in charge of Colonel S. Thayer.--The walls built for the protection of these islands need repairs, for which no funds are available. Improvement of the Patapsco river from Fort McHenry to mouth of said river, in charge of Major H. Brewerton.-Operations were suspended last year on the 15th December, and resumed this year on the 21st of May; the very boisterous weather in the spring preventing the laying out the channel at an earlier date. Both sides of the new channel were buoyed out this year-the eastern side with red buoys and the western side with white. Two new steam dredges with eight dumping scows and one steam tug have been added to the working apparatus this year, making the present force to consist of three steam dredges, twelve scows, one lighter, and one steam tug. The quantity of matter removed from the line of the new channel the last season, to include the 30th of September, is 80,150 cubic yards. Balance in treasury October 1, 1857.... $38,000 00 Probable amount to be expended by June 30, 1858....... 38,000 00 Removing obstructions at the mouth of the Susquehanna river, near Havre de Grace, Maryland, in charge of Major H. Brewerton.-For the reasons stated in former reports, no progress has been made in removing obstructions in this river. Improvement of the Appomattox river, below the city of Petersburg, in charge of Colonel J. L. Smith.-The city of Petersburg having purchased a powerful dredging machine, and entered into a contract with the United States to deepen the channel, the work done during the several months they have been engaged upon it must be considerable, and sufficient perhaps, or nearly so, to absorb the unexpended balance of the appropriation. No settlement on account of the contract has yet been made, and no report respecting the work has been received recently. Improvement of the harbor of Charleston, South Carolina, in charge of Captain G. W. Cullum.-Operations toward the opening of Sullivan's island channel under the contract between the United States and the commissioners of the fund appropriated by the State of South Carolina, referred to in my last annual report, were commenced in February last, and have been as steadily prosecuted as the unfavorable nature of the late working season and the imperfections incident to a new and hitherto untried machine would permit. The progress of the work and the results obtained have been very satisfactory, a sensible impression having been made on the shore constituting the bar of this channel, thereby much facilitating the passage of vessels through this entrance to the harbor. At the present rate of progress the channel might be opened in about a year; or by the substitution of certain new machinery in the dredger, the work might be accomplished in five or six months. The balance of the appropriation still available is, however, only about half sufficient for this object.-(For report of officer in charge, &c., see appendix A.) Removal of obstructions from Savannah river, below the city of Savannah, in the State of Georgia, placed there during the revolutionary war for the common defence, in charge of Captain J. F. Gilmer.-Early in the month of October, 1856, the work of dredging was resumed at the upper part of the wreck bank, where a sand bar had formed, filling, to some extent, the excavation that had been previously made by the machines; when this was removed, a greater width was given to the channel way dredged through the wrecks, making the total passage about three hundred feet wide, as proposed in the plan of the commission. Having perfected the dredging at this point, and at others in the vicinity, a revolving drag, attached to the tow boat, which had been used for towing mud flats, was worked along the excavated channel to give uniformity of depth, while the engineer of the dredge, assisted by a part of the crew, was employed in making essential repairs to the machinery preparatory to future operations. The results obtained by means of the revolving drag have been very satisfactory; first, by giving great uniformity of depth, and second, by gaining a small increase in depth of channel at all points over the obstructions. At the close of this operation, the soundings showed that there was no point of less depth than twelve feet at mean low water; or full eighteen feet at mean high tide. Under authority from the War Department, the dredge, tow-boat and flats, with the working force, have been employed in excavating a channel through the "knoll" off Cockspur island; and all current expenses and wear and tear of machinery, were paid by the city of Savannah. Satisfactory results have been obtained at this point, and a few weeks' work during the calm weather of next summer will give the desired depth and width of channel through this obstruction. Arrangements have also been made for the delivery of timber and other materials required for the construction of the deflecting work just above King's island, and the dredging machine has removed in part the southern edge of Garden bank. During the coming year, the construction of the work above King's island will be pressed forward, with a view to get an increased flow of water down Front river at the earliest practicable day, as this is all important to the preservation of the channel which has been excavated through the wrecks. The dredging machinery will be em ployed in removing the shoals in Front river at the points indicated in the report of the commission, February 11, 1853. 1857....... $83,000 00 Balance in treasury October 1, 1857.. Improvement of the river St. John's, Florida, in charge of Captain J. F. Gilmer.-A resurvey of the entrance was made, under an arrangement with the Coast Survey office, to determine the character of the changes which had occurred during the past year; but with the small means available for this work, no other operation has been undertaken since the last annual report. A proposition has, however, been recently made for maintaining for a time a depth on the bar which will accommodate the class of vessels at present employed in the trade of the river, and a contract will probably be entered into on the terms offered, which do not exceed the means at disposal. Repairs of the United States sea-wall at St. Augustine, Florida, in charge of Captain J. F. Gilmer.-The three or four coping stones, displaced by storms from the main wall, and a portion of the coping on the walls of the basin near the market, have been reset, and some minor repairs to the work made during the past year. Generally, this wall is in good condition, and requires no further immediate expenditure. Improvement of the harbor of Mobile, Alabama, at Dog river bar and the Choctaw pass, in charge of Captain D. Leadbetter.-As no funds were available for the preservation of the machinery belonging to this service, it was, in compliance with orders from the Secretary of War, sold on the 15th of October, 1856. The net proceeds of the sale were $1,082 82, the greater part of which has been applied in the payment of liabilities incurred on account of the work. No work has been done during the past year except the removal of six or eight snags from the channel. The superintendent urges the importance of continuing this improvement. (For report of officer in charge, &c., see appendix B.) APPENDIX A. WASHINGTON, D. C., October 20, 1857. GENERAL: I have the honor to submit, herewith, my annual report for the improvement of the harbor of Charleston, S. C., for the year ending September 30, 1857. After interminable delays, for which, as you are fully aware, I, the engineer in charge, have been in no manner responsible, the opening of Sullivan's island channel into Charleston harbor was finally commenced in February last, under the contract of July 11, 1856, with the commissioners appointed by the State of South Carolina "for the examination and improvement of the port of Charleston." Owing to stormy weather, inexperience in working the new dredging ma chine, and frequent breakings of its suction-hose, little was accomplished till June; since which, with short intervals, the work has steadily progressed, and the success of the novel process of dredging, which has been adopted, fully tested, and established. The whole amount of dredging accomplished to the 30th ultimo has been 21,482 cubic yards, the maximum day's work being 1,005 cubic yards, and the averages for June 388, for July 347, for August 266, and for September 538, or a general average of 328 cubic yards per working day. The operations have been confined chiefly to removing the part of Drunken Dick shoal which obstructs the western entrance to the channel. A very sensible impression has been made upon this shoal, and the passage of vessels in and out much facilitated. The materials removed from the channel are sand, broken shells, and occasionally post pliocene clay. A brief description of this new dredging machine may not be out of place. It consists of a large centrifugal pump, six feet in diameter, revolving upon a vertical axis, to which an iron 19-inch suction hose is attached, its lower or bell-mouthed end resting upon the bottom of channel. The pump is placed in the centre of a powerful propeller (where there is the minimum disturbance by the winds and waves) immediately under its deck in the hold of the vessel, and is worked by an engine supplied with steam from the propeller's boiler. The dredged material comes up in the form of very fluid mud and escapes at the circumference of the pump into the hold or well of the boat where the solid matter, about 20 to 25 per cent., is deposited, the water and two or three per cent. of sand escaping by the bow and stern overflows. When filled, the pump is disconnected and the steam turned on to the engine, and the steam engine used to propel the vessel to the place of deposit-Cummin's Point-a mile and a half distant. The deposition is easily effected, the bottom of the well being formed by shutters, which, when opened by a simple arrangement, allow everything to run freely out. This simple and admirable machine-the only one, according to my experience, suited to work in a rough sea-way-was invented by Mr. Lebby, of Charleston, S. C. Upon first seeing its model in 1855, being satisfied that it was constructed upon correct hydraulic principles, I expressed myself then, and often since, sanguine of its ultimate success, though I thought prudence dictated its trial in a rough sea upon a larger but inexpensive scale. So satisfied, however, were its proprietors, Messrs. J. M. & T. D. Eason, of its adaptability to dredging, confirmed by my approval, that, without further trial, they built the dredging machine now in use at a heavy outlay; and, conquering all obstacles, are now reaping the reward of their perseverance and enterprise. The power of the machine is so great that bricks, cannon balls, roots, bits of wrecks, and concreted sand and shells have been readily pumped up from the depth of twelve feet. At the present rate of dredging the channel will be opened in about a year. By substituting a larger pump, which could be worked by the same engine, and economizing power by some slight modifica tions of the machine, the whole work might be executed in five or six months. In my report upon the "preservation of the site of Fort Moultrie,' I have renewed my application, made every year since I have had charge of the public works in Charleston harbor, for an appropriation of $10,000 for building up the necessary parts of the existing jetties, particularly the inshore end of Bowman's. At the same time I propose removing, to the depth of 16 feet at low water, the extreme outer end of Bowman's jetty, which partially obstructs the western entrance into the channel. Both of these operations would tend to throw a larger volume of water into the channel, and aid, when once thoroughly dredged out, in keeping it open; but they should be done cautiously, and their effects most carefully watched by the engineer in charge. The balance now in hand of the appropriation by Congress will complete about half the dredging. This great and important improvement, so necessary to the commerce of the south, I trust, will be completed by the close of another summer, and the city of Charleston finally attain the consummation of its long cherished hopes. Respectfully submitted. GEO. W. CULLUM, Captain United States Engineers. Brevet Brig. Gen. Jos. G. TOTTEN, Chief Engineer, United States Army. APPENDIX B. MOBILE, September 30, 1857. SIR I have the honor to submit the following report relating to the improvement of Mobile harbor, by dredging at Choctaw Pass and Dog River bar, for the year ending September 30, 1957. As no funds were available for the preservation of the machinery belonging to this service, the department had authorized its sale at the date of my last annual report. The whole was disposed of at public auction on the 18th of October last. The net receipts of the sale were $1,083 82, the greater part of which has been applied in the payment of liabilities incurred on account of the work. No work has been done during the year except the removal of six or eight snags from the channel. The bay of Mobile is accessible to the largest merchantmen, which are compelled to lie in the lower part of the bay, and receive and discharge cargo by means of steam lighters communicating with the city. The depth of the water in the lower bay, and thence approaching the city through a distance of twenty miles, is sufficiently good, for it is not proposed at present to improve the channel for ships of heavy draught. But at seven miles from the city, at the lower part of Dog River bar, the depth becomes and continues less than 12 feet to the city, presenting a formidable obstruction to vessels of the coasting trade, as well as to those engaged in the export of lumber and naval stores. |
