C 2. HARBOR OF REFUGE AT NANTUCKET, MASSACHUSETTS. Nantucket Harbor is on the north side of the island of Nantucket. It has deep water inside, and would form an excellent harbor of refuge for vessels plying between the South and all Atlantic ports north of Cape Cod were it not for the shoal bar which obstructs its entrance. In the memorial to Congress on which the first appropriation was made for the work now in progress it was stated that more than 30,000 vessels annually pass through Nantucket Sound alone, and that more than 500 vessels have been wrecked around the island. ORIGINAL CONDITION. Before the commencement of the present works there was a shoal 14 miles in width outside the entrance, through which shoal the channel or line of best water was very crooked, and subject to changes in location. The ruling depth in the channel was about 6 feet at mean low water, and it has been about the same as far back as we have any record of it. The mean rise and fall of the tide is about 3 feet. PLANS OF THE WORKS. In 1829 a project for dredging a channel through the bar was adopted, and in the years 1829 to 1832, inclusive, the sum of $40,924.12 was expended in carrying it out. No permanent improvement resulted from this expenditure. The present approved and adopted project consists in extending jetties of riprap stone from the eastern and western sides of the entrance across the bar to deep water outside, for the purpose of concentrating the strength of the tidal currents and the excavation of a deep channel by natural forces. The western jetty was to be built first and the other as developments should show its necessity. AMOUNT EXPENDED AND RESULTS TO JUNE 30, 1883. The amount expended on this project up to the close of the fiscal year ending June 30, 1883, including liabilities outstanding at that date, was $65,769, and the result was the construction of the western jetty to a point 3,075 feet from its initial point on shore. OPERATIONS DURING THE LAST FISCAL YEAR. At the beginning of the last fiscal year the extension of the western jetty was in progress, under a contract with Mr. Charles H. Edwards, of Boston, Mass., which was described in the last Annual Report, and it continued until August, 1883, when the contract was completed. The delivery of riprap granite during the year under this contract was 3,784 tons. On the 15th of August, 1883, advertisements were issued for proposals for further extending the jetty, for a small quantity of riprap re 5908 E N-38 quired for building up a low place near the shore, and of chip-stone for filling interstices in an early-built part of the jetty which had been somewhat loosely built. The following proposals were received, and were opened September 6, 1883: Abstract of proposals. Names and addresses of bidders. Price per ton. Date of com- Date of com pletion. Charles H. Edwards, Boston, For 600 tons for inshore part, $2.60 per Oct. 1, 1883 July 31, 1884 James Scully, Groton, Conn.. For 600 tons for inshore part, $2.35 per Oct. 1, 1883 July 31, 1884 John Beattie, Leete's Island, For 600 tons for inshore part, $2.53 per Oct. ton; for 400 tons chip-stone, $2.53 per 1, 1883 July 31, 1884 Frederick K. Ballou, Mystic For 600 tons for inshore part, $2.77 per May 10, 1884 Aug. 31, 1884 Bridge, Conn. ton; for 400 tons chip-stone, $2.77 per ton; for the remainder, $2.77 per ton. The contract, with the approval of the Chief of Engineers, was awarded to Charles H. Edwards, the lowest bidder for the entire work. Dated September 18, 1883. Work under the new contract was commenced on the 6th of August, 1883, and it was continued during the fall and winter until the 2d of February, 1884, when, by reason of the continued severity of the weather, it was determined to postpone operations until the spring. On the 29th of April, 1884, they were resumed, and at the close of the year the work was still in progress. The amount of stone delivered under this contract during the fiscal year was 2,921.29 tons of stone for extension of the jetty, 608.32 tons of stone for building up the low place near the shore, and 400.71 tons of chip-stone. The usual comparative hydrographic surveys were continued as time could be spared from other work, and an extensive series of borings was made to determine the character of the bottom to 15 feet below mean low water along the proposed route of entrance between the jetties, and also on lines covering any probable position of the eastern jetty. In all cases the material was found to be sea sand, often mixed with gravel in varying proportions. Lieutenant Prescott, during his operations of 1829-32, reported the finding of clay under the surface of the bar, but the channel then dredged was probably much farther to the westward. No clay was discovered in the borings of the last fiscal year. In May, 1884, a careful survey was made by Assistant Engineer Norman W. Eayrs and party, in the United States schooner Surveyor, of the area east of the western jetty and in the harbor, from which to discover what changes had occurred during the last year. Observations also were made by current meter and float on the velocities of the tidal currents in the throat of the harbor, and, by means of two sets of simultaneous tide-gauge observations, made at four equidistant stations in the upper harbor at the two instants of high and low slackwater at the mouth of the harbor respectively, data were obtained from which the contents of the tidal prism extending up to the "head of the harbor" have been calculated. Assistant Engineer W. H. Lawton, jr., was local inspector of the work until February 3, 1883, and Mr. T. A. Churbuck was local inspector from April 14, 1884, to the close of the year. AMOUNT EXPENDED AND PROGRESS DURING THE LAST FISCAL YEAR. The amount expended during the year, including liabilities outstanding June 30, 1884, was $22,412.11. The western jetty was extended 440 feet, making a total distance of 3,515 feet from the initial point on the shore. The distance at the close of the year of the end of the jetty from the 12-foot curve on the outer side of the bar was about 2,371 feet. OPERATIONS CONTEMPLATED FOR THE FISCAL YEAR ENDING JUNE 30, 1885. With the available remainder of the appropriation of August 2, 1882, it is proposed to complete the current contract for extending the western jetty. This contract will expire July 31, 1884. It will probably carry the outer end to a point about 4,016 feet from the shore end, or to about 1,870 feet from the 12-foot curve on the outer slope of the bar. The small amount remaining after the completion of the current contract, about $400, will be reserved for lighting the extremity of the western jetty until work shall be resumed and for repair of possible damages by waves and ice. It has been intended to devote the next appropriation to the commencement of the construction of the eastern jetty, since it has been found that the scouring of a deep channel through the bar will require more concentration of the strength of the tidal current than can be effected by a single jetty; but the inner part of the eastern jetty, which will be left at a low level, so that it will not interfere with the proper filling of the tidal prism by the flood te should not be undertaken before sufficient means are provided for in ishing it in one working season, for otherwise its construction might prove temporarily inconvenient to the local commerce of the port. It is proposed to hold the amount appropriated by the act of Congress of July 5, 1884 ($10,000), until the whole amount of the estimated cost of this portion of the eastern jetty (not less than $85,000) can be made available. It is earnestly hoped, therefore, that not less than $75,000 will be appropriated at the next session of Congress, so that by commencing early in the summer of 1885 this part of the work can be completed before the winter of that year. The original project for this important harbor of refuge was estimated to cost $238,000, and the amount (estimated) required for completion of the existing project, which will be found below, is the part of this originally estimated cost of the whole work, which has not yet been appropriated. This estimated cost will, however, be found to fall short of the actual cost of the completed work, since the cost of riprap stone per ton, delivered in the jetty on the bar at Nantucket, has been found to be much in excess of what was anticipated, and the length of the eastern jetty must be greater than that of the western jetty, instead of the same length, as was contemplated. A revision of the amount necessary to complete the works will be made as soon as the proposed location of the eastern jetty has been approved and in time for the next Annual Report. The amount thus far appropriated for the work is $110,000. Nantucket is in the Nantucket collection district, and it is a port of entry. The amount of revenue collected in the last fiscal year was $288.68. The nearest lighthouses are Nantucket Cliff and Brant Point lights. The nearest fortification is the fort at Clark's Point, New Bedford, Mass. |