T 2. REMOVAL OF BULK-HEAD ROCK, PROVIDENCE RIVER, RHODE ISLAND. An appropriation of $2,500, "for the improvement of Bulk-head Rock, in Providence River, Rhode Island," was made in the civil appropriation act of July 15, 1870. This amount was based on an estimate made by Captain A. H. Holgate, United States Engineer, in a report dated June 5, 1870, printed as Senate Executive Document No. 105, second session, Forty-first Congress. He found the least depth of water on it to be 8 feet at mean low tide, and thought that it should be removed so as to give a depth of 16 feet. The amount to be removed he estimated at 25 cubic yards; and the cost, including "unforseen expenses," $100 per cubic yard. To do this work I engaged Mr. George W. Townsend, of Boston, at $85 a day, he furnishing a sloop fitted with hoisting apparatus and hoisting engine, and his patent drill, and one foreman, one engineer, one driver, and six men, the United States furnishing the necessary powder and exploders. Mr. George H. Mann, civil engineer, was placed to superintend the operations. He made a survey of the rock, in October, before beginning work, a map of which is sent herewith. This showed the least depth on the rock, at mean low water, to be 8.9 feet, and the amount to be removed, down to the 14-foot curve, to be 27 cubic yards. As this exceeded the amount estimated by Captain Holgate to make 16 feet depth, the improvement could not be carried deeper unless the expense should prove to be less per yard than in his estimate; and my experience with Mr. Townsend's work on Middle Rock, New Haven Harbor, did not lead me to think it would be. Mr. Townsend was employed sixteen days, about eleven of which were in blasting upon the rock, the others being occupied in getting and placing mooring, stones, &c., after which a survey was made, (copy of the map sent herewith,) and the depth was found to have been increased so as to make at least 14 feet at mean low water. The work was then stopped, the appropriation having been exhausted. This rock, as shown by the map of it first made, was very much in ridges, and its structure being a conglomerate, made it very brittle. It was therefore a favorable case for surface blasts, and these were the kind made by Mr. Townsend's party, with the exception of a single hole drilled into a projection above the 14-foot line, just before the work was stopped. It was necessary to raise only about 15 tons of stone, the rest being thrown off alongside. The amount of powder and exploders used was very large. The following is a statement of them: Allowing for eleven days' actual work in blasting, the removal of 27 cubic yards cost as follows: For powder and exploders and cans......... For eleven days' work of Townsend's party, at $85. Making 27 cubic yards, at $60 90.... Mr. Townsend's party was paid for five other days at $85.... Hire of men and vessels in making survey. $709 33 935 00 1,644 33 $425 00 50.00 100 00 38 00 242 67 2,500 00 I have been particular in reporting the expenditures on this work, so that the experience may have its full value in making future estimates. The Bulkhead Rock now has a depth of water, at mean low tide, of 14 feet, and at mean high water of 19 feet. At low water.of spring tides there is 133 feet, and at high water of spring tides, 194 feet. Accompanying this report is a United States Coast Survey chart, showing the corrected location of the rock. The appropriation of $5,000, under which the first dredging was done, at the Crook, by Captain Dutton, in 1853, was for "removing a rock near the mouth of Seekonk River, harbor of Providence." Captain Dutton says, in his report of December 29, 1852: "Upon full investigation made at that place concerning the obstruction in question, it was ascertained that there was no rock obstructing the navigation in the waters of that harbor; nor, according to the most experienced pilots of the place, in the navigable portion of the Seekonk or Provi dence Rivers." Captain D. must have misapprehended the length of the Providence River, which, by the United States Coast Survey Chart, extends down to Conanicut and Nayatt Points, a distance of eight miles below the junction of the Seekonk River, while Bulkhead Rock is only two and one-half miles below this junction. To make 17 feet on this rock at mean low water will now require the removal of about 90 cubic yards of rock. To make 18 feet will require the removal of 130 cubic yards. This latter amount should be removed eventually, but I do not consider it a pressing necessity of the present time, and submit no estimate for the purpose. The improvements that are being made in submarine blasting will make unreliable in the future any estimate based on past experience, and the amount of rock to be removed being stated, the cost of it can better be estimated when the time comes to do the work. The nearest port of entry is Providence. It is in the Providence collection district, and the revenue collected there for the fiscal year ending June 30, 1871, was $203,862 43. T 3. IMPROVEMENT OF THE PAWTUCKET RIVER, RHODE ISLAND. At the date of my last annual report, September 30, 1870, nothing had been done on this work except the making a contract with Mr. Emory R. Seward, of Albany, New York. By the terms of his contract he was to commence work on the 1st of October, 1870, and complete it by January 1, 1871, but, for various reasons, he failed to commence until the 10th of December, and was compelled to stop in the latter part of the same month by the ice. The time for completing his contract was extended to June 30, 1871. He resumed work on the 1st of April, and by the 30th of June had excavated 16,257 cubic yards, leaving an unexpended balance on hand at that time of about $1,000. The dredge employed excavated with some difficulty the hard slaty material of which a portion of the bottom of that part of the river is composed. This dredging was confined to that part of the Pawtucket or Seekonk River from 500 feet below Duanel's wharf to the town of Pawtucket, a distance of about half a mile, making there a channel of 75 feet in width and with a depth of 6 feet at mean low water. The greatest draught for vessels going to Pawtucket before this dredging was done was less than 43 feet at mean low water. The mean rise of the tide here is about 5 feet. The depth is now 1 foot greater above Dunnel's wharf than in some places below it. In October and November 1870, a survey of that portion of the river between Pawtucket and Bishop's Point was made by Mr. N. E. Russell, civil engineer. A copy of his report is appended. Additional surveys were made by J. H. Dager, civil engineer, from Swan Point to Spring Run, and from Bishop's Point to Swan Point by H. A. Bentley, civil engineer; these surveys were made by them while superintending the work of dredging. A map of the river from these surveys accompanies their report. It shows the condition of the river before the work of improvement under my charge was commenced. On the 29th of April, I advertised for proposals for dredging, under the appropriation of $7,000, approved March 3, 1871, and on the 7th of June they were opened. The following is an abstract of the bids received: Abstract of proposals for improvement of the Pawtucket River, Rhode Island, received at the Engineer Office United States Army, Newport, Rhode Island, Wednesday, June 7, 1871. The contract was awarded to Mr. T. J. Hill, of Providence, Rhode Island, at 33 cents per cubic yard. Mr. Hill was, at the time of making his proposal, doing some dredging for the city of Providence, but thought he was at liberty to leave it if he wished, but when he got ready to commence work on the river, the city authorities refused to let him off until the work was finished. The work was then offered to Mr. Edgar M. Payn, of Albany, New York, whose bid was the same as Mr. Hill's. He accepted the offer and commenced work August 12, 1871. To make the channel below Dunnel's wharf 75 feet wide, with a depth of 6 feet at mean low water, will require the removal of about 31,000 cubic yards. The funds now available will make a channel-way of this depth and width down to Spring Run. This work is now in progress. The improvement of this river has been quite satisfactory, increasing the range of tonnage of vessels running there about twice. It is considered advisable to continue this improvement by increasing the width and depth of the channel. The funds available will be expended during the fiscal year. Amount asked for fiscal year ending June 30, 1873, is $10,000. Pawtucket is situated in Providence collection district, and Providence is the port of entry. Amount of revenue collected in the fiscal year ending June 30, 1871, was $203,862 42. UNITED STATES ENGINEER OFFICE, Newport, Rhode Island, February 18, 1871. GENERAL: I have the honor to submit the following report of the survey of Pawtucket River, Rhode Island. This survey, preparatory to the dredging operations just begun, was commenced in the latter part of October, 1870, and extends from Smith's wharf, in the town of Pawtucket, to Bishop's Point. The shore-line was run in by myself and Mr. H. N. Babcock, mechanical engineer, and on the 3d of November, assisted by Messrs. L. S. Chase and J. P. Vose, I began to make the soundings. We found the material of the bottom to be composed of coarse gravel, rock, sand, and some soft mud, and that the channel-way, as at present existing, has an average depth of nearly five feet over the distance covered by the survey. The principal obstructions were above Dunnel's wharf, and seem to have been caused, in part, by deposits from drains leading from the town of Pawtucket. This, however, of itself, was not the only cause of the filling which has taken place at some points, The current of the river, at all times quite perceptible, formerly tonched the east bank of the river at Smith's wharf, and the channel ran on this side; but a few years ago it was turned from its natural course by wharves built on the other side, thus removing the current from the place XY, (formerly deep water,) which became filled up with sediment from a neighboring sewer. This sewer is a common box-drain about 2 feet square, and down which great quantities of fine gravel and sand come after every rain-storm. The bottom is laid bare at this point by the fall of the tide, and its appearance shows plainly how this deposit has been made. A small peg driven into the bed of this formation, XY, near shore, and firmly enough to prevent its being washed away, was allowed to stick up about an inch above the general surface. This was the day before the rain-storm which occurred on the 19th of October, 1870, and the next day it had entirely disappeared. Just below this point is another shoal place, marked Z, in the channel, and which makes a great deal of trouble to vessels coming up at medium tide. This is the spot at present being dredged, and it would seem that any channel cut from the deep water opposite Smith's wharf to this point must be more or less affected by the deposit before mentioned. By reference to the map it will be seen that a channel of the requisite width has been marked in the direction which will necessitate the least amount of excavation. The average depth of this at present has already been stated. The mean rise and fall of the tide was 5.08 feet, and was determined by such observations as were not so much disturbed by winds as to make them of no value. Those used were taken on the 27th, 28th, and 29th of October, and on the 5th, 7th, 8th, 9th, 10th, and 11th of November, 1870. The observations are appended to this report. The method of finding mean water marks and mean rise and fall of water was as follows: 1st. The height of low-water mark on the gauge for each day was subtracted from its corresponding high-water mark on the gauge, and the sum of these results for all the days used, divided by the number of days, was called the mean rise and fall of the water. 2d. The sum of the heights of high-water mark on the gauge, divided by the number of days, was called mean high-water mark on the gauge. Low water was determined in the same way, or by subtracting from mean high-water mark the mean rise and fall of the tide, as before determined. 3d. Mean water was taken as intermediate between mean high and low water marks. Soundings were reduced to mean low water. The mean rise and fall of the tide being 5.08 feet, the proposed excavation to a depth of 6 feet at mean low water will give a depth of over 11 feet at mean high water between the extreme points indicated on the map. The amount of excavation to secure a channel 6 feet deep at mean low water, and 75 feet wide, from opposite Bishop's Point to Smith's wharf, in Pawtucket, has been completed, and is about 13,651 cubic yards. I am much indebted to Messrs. Chase and Vose for valuable assistance rendered on this work. |