mated that the sum of $70,000 will suffice to give a depth of eight feet as the lowest water, and that the sum of $10,000 expended annually will suffice to maintain this depth. (Appendix R.) 4. Improvement of Thames River, Connecticut.-The work on this river has consisted in deepening the channel below the city of Norwich to obtain a depth of fourteen feet at high water. It is expected that this will be completed during the present working season, and that a suffiçient balance will be left to enable an examination to be made next season for the purpose of ascertaining the effects of the work. No estimate is submitted for the fiscal year ending June 30, 1871. (Appendix R.) 5. Improvement of Providence River, Rhode Island, at "the Crook."No work has been done on this river during the year. The engineer in charge reports that the sum of $10,000 per annum could be advantageously applied in dredging the channel of this river below the Fox Point wharf. Required for the next fiscal year, $10,000. (Appendix R.) 6. Improvement of Pawtucket River, Rhode Island.-The small balance remaining on hand at last report has been expended in dredging. To complete the work deemed necessary, viz: dredging to obtain a channel six feet deep at mean low water, will require an appropriation of $15,000, which amount is required for the next fiscal year. (Appendix R.) 7. Survey of Bridgeport Harbor, Connecticut.-A resurvey of this harbor was made last year, and from a careful study of the changes in the harbor that this survey has developed it is not deemed by the engineer in charge necessary to recommend the construction at this time of any works of improvement. The channel and harbor facilities are essentially as good as shown by the survey of 1837. The channel at its present depth is an artificial one made by dredging. That it remains unchanged as to depth is evidence that no serious injury has been sustained. It is doubtful whether there is any permanent remedy for the evil anticipated by those interested in this harbor. The effect of storms on the sandy bottom of a shoal harbor is necessarily to shift the channel more or less, and if it should be found in future that the channel is not maintained by the action of the tidal currents it will be necessary to excavate as was formerly done. (See Appendix R and R 1.) 8. Plymouth Beach, Massachusetts.—This work was in charge of Brevet Major J. A. Smith, captain corps of engineers, until June 1, 1869. Two hundred lineal feet of substantial crib-work of timber covered with plank, and one hundred and seventy-five feet of triangular work, similar to that before used, were completed last autumn. One crib one hundred feet long was framed and another partly built, neither of which could be put in position, owing to the unusual inclemency of the season and the attendant expense. The beach is greatly exposed to the action of the sea, owing to the unfinished condition of those works intended for its preservation. A projet and estimate will be made as early as practicable for the preservation of the beach, upon which the existence of the harbor depends. Amount allotted to this work from appropriation for repairs of harbors on the Atlantic coast Amount expended during the fiscal year ending June 30, 1869.. (See Appendix R.) $7,500 00 7,423 39 PRESERVATION AND IMPROVEMENT OF BOSTON HARBOR; PRESERVATION OF THE HARBOR OF PROVINCETOWN; IMPROVEMENT OF THE HARBOR OF NEWBURYPORT, AND SURVEY OF THE MERRIMAC RIVER. Officer in charge, Brevet Major General J. G. Foster, lieutenant colonel corps of engineers, assisted by Brevet Lieutenant Colonel G. L. Gillespie and Brevet Major George Burroughs, captains corps of engineers. 1. Dredging off the southwest point of Lovell's Island.-The work has been carried on steadily by the contractor, who removed 66,909.54 cubic yards, widening the channel to 600 feet at the 16-feet curve, with an average depth of 16 feet. By the close of the season it is expected that this depth will be increased to 23 feet. (See Appendix S.) 2. Dredging channel across the Upper Middle Bar.-Four hundred and fifty cubic yards of material have been removed. The work has been suspended and the amount heretofore allotted for this work has been transferred to the dredging at Lovell's Island. (See Appendix S.) 3. Blasting and removing Corwin Rock.-This rock and an adjoining ledge has been entirely removed to a depth of 23 feet at low water. 1,356 tons of rock have been blasted; 1,192 tons deposited on shore, and 164 tons allowed to remain in deep water. The channel formerly between this rock and Tower Rock has been widened by the removal of these rocks from 250 feet to 600 feet. (Appendix S and S 1.) 4. Blasting and removing Barrel Rock.—A survey of this rock was made as well as contracts for its removal, and the preliminary preparations for active operations This rock has since been removed. (See Appendix S.) 5. Sea-wall at Point Allerton.-The title to the land for the site of the wall (forwarded in January last) has not received the approval of the Attorney General yet; as soon as this is obtained, proposals will be invited for the construction of the wall. (See Appendix S.) 6. Sea-wall at Gallup's Island.-This work has steadily progressed; 558 feet of foundation and 456 feet of wall has been built. (See Appendix S.) 7. Sea-wall for the preservation of the North Head of Long Island.—The jury of the county court has determined upon the amount to be paid by the United States for the site of this wall, and the fortifications to be erected there. As soon as this amount is paid, either to the owners or to the judge of the court, (according to an act of the legislature of Massachusetts,) and the title receives the approval of the Attorney General, preparations for active work will be made. Estimates for the fiscal year ending June 30, 1871, for continuing the preservation and improvement of Boston Harbor, a portion of which should be made available for the present fiscal year: For dredging at Lovell's Island, to complete the work.... For dredging at Upper Middle Bar.. 100,000 00 For sea-wall at Point Allerton, to complete. 40,000 00 40,000 00 For contingencies. Total.. 15,000 00 330,000 00 8. Preservation of Provincetown Harbor.-At Beach Point a brush bulkhead and jetties have been constructed which are fast gathering the floating sand. A dike to guard against any possible breach by the sea through the outer beach has been constructed across the Salt Meadows and East Harbor Creek at High Head. The current and tidal observations in the immediate charge of Captain George Burroughs, brevet major United States Army, have been completed. An allotment of $9,000 from the appropriation of 1869 was made for the construction of certain works for the preservation of the harbor urgently needed, which will be expended this season. Amount required to be appropriated for the fiscal year ending June 30, 1871, $25,000. (See Appendix S and S 2.) 9. Merrimac River.-Surveys have been made of the obstructions in this river, and a report with estimate of cost of removal submitted. (See Appendix S and S 3.) SEA-WALLS AT GREAT BREWSTER, DEER, AND LOVELL'S ISLANDS, BOSTON HARBOR. Officer in charge, Brevet Major General H. W. Benham, colonel corps of engineers. 1. Great Brewster.-The work of the fiscal year comprised the setting of the heavy shell-stone paving in rear of the whole of the most exposed portion of the east face of the North Head, about 700 running feet; filling the rear of about 400 feet of other portions with earth, covered in the most exposed parts with small bowlders as a temporary protection against the dash of the sea, and the construction of a strong stone pile jetty to protect the west corner of the wall of South Head. It is expected that at the close of the present working season all the work remaining to be done for the complete protection of the North Head, together with two or three jetties at the angles, will be finished, so that all that now appears necessary for the protection of the island will be completed this season, and no further appropriation for this object will be required. 2. Deer and Lovell's Islands.-Upon the sea-wall at Deer Island 1,250 running feet of the wall of the North Head had been rebuilt and repaired up to the close of the present fiscal year, (June 30,) making in all about 2,210 running feet of wall rebuilt on the three bluffs of the island since 1865. All the most exposed parts of this wall are now repaired. The engineer in charge recommends as an additional security that some 200 or 300 feet of the North Head wall be rebuilt at a cost of about $8,000. At Lovell's Island a strong but small wall of about 800 feet in length, with four jetties at the angles, has been built to protect the southeast bluff, which appear to answer the purpose and to increase the breadth of the beach in front of it. An apron facing of stone, protected by concrete, has been constructed in front of the eastern half of the old wall Some further repairs and a new jetty are recommended at a cost of about $2,000. IMPROVEMENT OF HARBORS IN THE STATE OF MAINE. Officer in charge, Brevet Brigadier General George Thom, lieutenant colonel of engineers. 1. Saco River improvement.-These improvements consist in the rebuilding of some of the most important piers in the river, the removal of the sunken rocks, and the construction of a breakwater at the mouth of the river. On the 30th of June, 1869, the sunken rocks had all been removed from the channel near Little Islands, and the breakwater at the mouth of the river had been partially built for a distance of 4,000 feet out from the shore, containing 51,223,85 tons of stone. The first 2,550 feet of this breakwater is built up to a general level of nine feet above mean low water, with an average thickness of twenty feet, the remaining portion forms but the "core" of the work to be built, and is barely sufficient to divert the channel as required, or to withstand the violent storms to which it is exposed. This work in its present unfinished condition has accomplished all that was expected from it. It has closed the old North Channel, (as was intended,) and formed a new one, (as was desired,) which is deeper, much more uniform and direct along the inside of the breakwater as far out as it extends, and it is apparently improving beyond that point. To complete this work in a proper manner, it must be increased throughout in height and thickness, and extended. The additional amount required for the completion of all the improvements proposed at this time (exclusive of the capping of the breakwater estimated for in previous reports) is $60,000, which amount can be profitably expended during the fiscal year, ending June 30, 1871. (See Appendix U.) 2. Extension of the breakwater and improvement of the harbor at Portland, Maine.-The capping of the unfinished portion of the breakwater has been completed, in all 7334 lineal feet. Under a joint resolution of Congress, approved June 5, 1868, the harbor has also been improved by dredging a channel through the "Spit," near the "middle ground," in which there are now twenty feet of water at mean low water, or twenty-nine feet at mean high water. A contract has also been made for excavating a new channel through the "middle ground bar," to be completed on or before the first of November, 1869, and it is probable that it will be completed in that time. On hand July 1, 1868.. On hand July 1, 1869... $79,397 87 64, 491 82 Which amount will be expended by the close of this working season in deepening the channel. For finishing the breakwater, an additional sum will be required of $40,000. (See Appendix U, U 1 and U 2.) 3. Improvement of the Kennebec River, between Gardiner and Augusta, Maine. This work consists in straightening and deepening the channel of the river, by dredging through several shoals and the removal of rocks which obstruct it between Gardiner and Augusta, Maine. The width of the channel estimated for is one hundred feet at bottom, with sides having a slope of two feet to one foot rise, and a depth of seven feet up to Hallowell, and six and one-half feet thence to Augusta, at low tide in the lowest stages of the river, being about twelve feet at high tide in the same stages. The channel has been completed through Hallowell and Shepard's Point Shoal (at and below Hallowell) to a width of 75 feet, and is in progress to the same width through Britt's Shoal, above Hallowell, which will probably be completed before the 1st of October, 1869. The channel through Gage's Shoal will, it is probable, be more than half completed during the present season. About thirty bowlders have also been removed from the river at Shepard's Point, Hallowell and Britt's Shoals. The additional amount required to complete the channel from Gardiner to Augusta, (through Hinckley's Shoal and the unfinished portion of Gage's Shoal,) and to increase the width of the new channel throughout to one hundred feet, is estimated at $22,500. (See Appendix U.) 4. Improvement of the navigation of the St. Croix River, above the ledge. For this improvement it will be necessary to deepen its channel by the removal of slabs, edgings, and sawdust which for thirty years and more have been accumulating in large quantities in this river. The act making an appropriation for this improvement requires the co-operation of the province of New Brunswick, which has not yet been obtained, so that operations have not yet been commenced. Amount appropriated for this work.... $15,000 00 35, 000 00 It being understood that the province of New Brunswick will contribute an equal amount for this purpose. (See Appendix U.) 5. Survey and improvements at Richmond's Island, Cape Elizabeth, Maine. A survey of this locality has been made, with a view to forming an estimate of the probable cost of a breakwater to connect the island with the main land. Such a breakwater would form a good harbor of refuge, affording safe anchorage and good holding ground, with the wind from any point between north and southwest, affording refuge to vessels prevented by northeast storms from entering Portland or adjacent harbors. The breakwater to be permanent should be built of rubble stone, of which the engineer in charge estimates that there will be required 68,000 tons. This, when placed in the structure, would cost $93,000. Amount which can be profitably expended during the fiscal year ending June 30, 1871, $50,000. (See Appendix U.) 6. Improvement of the "Gut" Back River, opposite the city of Bath, Maine.-Owing to the contraction of the channel of Back River at the upper Hell Gate, the tidal current runs through this gate with such violence as to endanger the navigation at any other time than at high and low water, except for steamers. The difficulties are still further increased by a large rock, known as "Boiler Rock," which lies in midchannel some seventy-five yards below the gate. The engineer in charge examined this rock with the aid of a submarine party. It lies in from three to four fathoms water at low tide, its highest point being only about three feet below the surface at mean low water, and ten feet below |