copy was sent to Lieut. Col. Henry M. Robert, Corps of Engineers, April 19, 1893.

6. Bridge of Mobile County, Ala., across Three Mile Creek.-Complaint was in June, 1892, received at this office that this bridge, having no draw, was an obstruction to navigation. To remedy the difficulty the county commissioners submitted plans March 20, 1893, for replac ing the structure with a drawbridge; approved by the Secretary of War April 24, 1893; copy sent to Maj. A. N. Damrell, Corps of Engineers, April 25, 1893.

7. Bridge of the city of Frankfort and county of Franklin, Kentucky, across Kentucky River.-Under the provisions of act of September 19, 1890, notices, dated September 8, 1891, were served on the county and city authorities requiring, among other alterations to render navigation under the bridge free and unobstructed, that it be raised to a height of 48 feet 4 inches above normal pool level. (See Annual Report, Chief of Engineers, 1892, p. 411.) Plans for reconstructing the city bridge with a clear elevation of 43 feet 4 inches (which reduced height the Secretary of War had authorized in the case of a neighboring bridgesee above, p. 471) were submitted May 8 and approved by the Secretary of War May 22, 1893; copy was sent to Maj. D. W. Lockwood, Corps of Engineers, May 24, 1893.

BRIDGES OBSTRUCTING NAVIGATION.

Under the requirements of sections 4 and 5 of the river and harbor act approved September 19, 1890, the Secretary of War notified the persons, corporations, or associations owning or controlling certain bridges obstructing navigation, after giving them a reasonable opportunity to be heard, to so alter said bridges as to render navigation through or under them reasonably free, easy, and unobstructed, specifying in the notice the alterations required to be made, and prescribing a reasonable time in which to make them, as follows:

1. Bridge across Buffalo Bayou, Texas, near Houston, Tex.-Notice, dated September 14, 1892, served on the president of the San Antonio and Aransas Pass Railroad Company, October 24, 1892. Alterations required: The construction of a line, 252 feet long, of fender piles on the left bank, and one, 54 feet long, on the right bank, as indicated by the red dotted lines on the attached drawing; the piles to be 5 feet apart between centers, to be well driven, and to be cut off at an elevation of 13 feet above the level of mean low water at the locality, and to be strongly connected with each other on the inner or shore side of the line of piling by two lines of 6 inches by 12 inches string pieces placed horizontally; the lines of fender piles to be well braced by timbers bolted, at intervals of 10 feet, to the fender-piling and to a row of piles between the fender-piling and the shore; the removal of the false work to the level, at least, of the tops of the fender-piles; the removal of any obstructions on the channel sides of the lines of fenderpiling that may have been placed in the bayou; and the removal, or sawing off, of the ends of any caps pertaining to the false work that may project into the bayou beyond the channel sides of the fenderpiling. Alterations to be made and completed on or before January 24. 1893.

The alterations have been completed.

2. Bridge across Dickinson Bayou, Texas.-Notice, dated February 13, 1893, served on George J. Gould, president of the Galveston, Houston and Henderson Railroad Company, February 20, 1893. Alterations

required: Remove the seventh bent from the right bank and replace that part of the bridge which now spans the space between the sixth and eighth bents from the right bank by girders or other construction so as to afford a clear width of not less than 24 feet and clear headroom of not less than 13 feet above low water for the free passage of boats, and clear from this space all piling or other obstructions to navigation that may have been placed there by the company; all as indicated on attached tracing. Alterations to be made and completed on or before May 20, 1893.

Owing to a misunderstanding in serving the notice, the work in mak ing the alterations was delayed. The superintendent of the bridge and building department of the railroad company has acknowledged service of the notice, and promised that the alterations will be made as soon as possible.

3. "Portland Bridge," across Fore River, Portland Harbor, Maine.Notice, dated February 20, 1893, served on the chairman of the board of county commissioners of Cumberland County, Me., February 24, 1893. Alterations required: The draw openings of the bridge to be modified so as to give a clear width of not less than 70 feet in each; the new draw to be located so that the north end will not reach beyond the existing turntable pier; the new drawpier to be set practically parallel to the existing harbor commissioner's line on the Portland City front; and the existing drawpier and other parts of the bridge not utilized in the new structure to be removed. Alterations to be made and completed on or before February 24, 1894.

In March the county commissioners submitted plans for the altera tions of the bridge, which were approved by the Secretary of War, and the engineer officer in charge of the district where the bridge is located was charged with the supervision of constructing the alterations. (See above, p. 472.)

4. "Washington Bridge," across Housatonic River between Stratford and Milford, Conn.-Notice, dated February 20, 1893, served on the secretary of the joint bridge board of Fairfield and New Haven counties, Conn., March 2, 1893. Alterations required: (1) That a swing draw be constructed in the bridge at or near the middle of the river; (2) that the clear width of opening on either side of the middle or pivot pier of the draw be not less than 80 feet; (3) that the location of the center of such pivot pier be not less than 265 feet nor more than 340 feet from the east abutment of the bridge as it now stands; (4) that any parts of the existing piers, or foundations of, or riprap around the same, which lie within the draw-spans, be removed to a depth of not less than 12 feet below mean low water; (5) that the piers on either side of the draw openings be inclosed by suitable guards, piers of timber, and piles above and below, to prevent vessels striking the piers. Alterations to be made and completed on or before December 1, 1893.

The board of commissioners have decided that it will be expedient to build a new bridge, and have prepared plans for the same in compliance with the notice. Contracts for the work are about to be let.

5. Bridge across Sakonnet or Seaconnet River at Tiverton, R. I.— Notice, dated July 1, 1893, served on the president of the Old Colony Railroad Company, July 7, 1893. Alteration required: To provide the bridge with a draw having an opening of 100 feet in width in the clear. Alterations to be made and completed on or before July 1, 1894.

On the 1st of July the president of the company was advised by the Acting Secretary of War that the needs of navigation will probably soon require the opening to be deepened to twenty-five feet depth at low water, and that the piers and abutments of the span ought to be constructed accordingly.

OCCUPANCY OF AND INJURY TO PUBLIC WORKS BY CORPORATIONS AND INDIVIDUALS.

Under the requirements of section 2 of the river and harbor act approved July 5, 1884, and section 4 of the river and harbor act approved August 5, 1886, there are submitted herewith reports of officers in charge of river and harbor districts of instances in which piers, breakwaters, or other works built by the United States in aid of commerce or navigation are used, occupied, or injured by corporations or individuals. (See Appendix A A A.)

MISCELLANEOUS.

[Public works not provided for in acts making appropriations for the construction, repair, and preservation of works on rivers and harbors.]

MAINTENANCE AND REPAIR OF WASHINGTON AQUEDUCT-INCREASING THE WATER SUPPLY, DISTRICT OF COLUMBIA-ERECTION OF FISHWAYS AT GREAT FALLS.

Officer in charge, Col. George H. Elliot, Corps of Engineers.

1. Washington Aqueduct.-No damage has been done to the masonry dam at Great Falls during the last fiscal year, and it is in excellent condition. Some of the riprap back of the dam that was carried away by ice in previous fiscal years was not replaced during the last year, by reason of the inadequacy of the appropriation for preservation and repair and the pressure of more immediately important work. A shoal at the mouth of the feeder to the conduit at Great Falls, which interfered with the proper supply of the conduit, was removed.

The conduit between Great Falls and Wasteweir No. 2 was flushed several times during the year for the purpose of preventing further deposits; but the greater portions of the accumulations that the officer in charge found in his inspection of the interior of the conduit in 1891, and were estimated at 15,500 cubic yards, remains as at the date of the last Annual Report. An appropriation for their removal is asked for. Two experiments that were made to find for the 9-foot conduit between the two reservoirs the value of the coefficient C in the Chezy formula, showed its values for this portion of the conduit to be 82.8 and 96.1, the crown of the conduit arch being under a pressure of about 4 feet and the mean velocities through the conduit being 0.95 foot and 1.1 feet per second, respectively.

A wooden flume 16 feet long and 10 feet wide was constructed for the purpose of preventing the wearing of the banks of the stream into which Wasteweir No. 3 is discharged. An application to the Secretary of War, by the owner of the land through which the stream flows, that Congress be asked to provide for the removal of this weir, which has been in use for about thirty-five years, was refused; but he was informed that if he should make an application to have a pipe laid

through the land for carrying off the water from this weir, it would receive the consideration of the Department.

The Conduit road has been repaired during the year, and that portion of it that is between the two reservoirs is in excellent condition. The further side of Dalecarlia Hill has been graded and made ready for a macadam pavement, and about 700 feet of fencing has been done along the road near the upper reservoir. Attention has again been called to the damage to the road by the earth and clay washed down upon it from the newly excavated streets in the subdivision called Whitehaven, and it is to be hoped that the necessary steps will be taken by the proper authorities to prevent it.

The officer in charge has submitted his project for the expenditure of the $60,000 appropriated by the act of March 3, 1893, for commencing the improvement of the receiving reservoir, and it may be found in detail in his report. On account of the delicacy of the work of blasting out the drainage tunnel through Dalecarlia Hill, under the aqueduct tunnel, it will be necessary to do the work required by this project by days' work, and this, as authorized by the act, has been approved by the Secretary of War. It is hoped that the remaining $90,000 of the $150,000 contemplated by Congress as the entire cost of this work, which is so important to the District of Columbia, will be voted at its next session.

A survey and plan for carrying off the drainage from the underground valve chamber at the distributing reservoir was made during the year. The present outlet for this drainage is through a valley through private land which has recently been bought by a syndicate and laid off into streets. It is liable to be stopped up at any time by the filling up of the valley, and in case of stoppage it would cause the spring water in the ground around and above the arches (that now flows freely into the valve chambers through openings made for the purpose) to submerge the main valves and prevent the regulation of the supply of water to the city.

During the year the raising of the walls around the south connection of the upper reservoir to prevent an undue strain on the conduit in floods has been completed by placing the coping thereon; the masonry chamber for the valve on the blow-off from the by-conduit at the spillway from the same reservoir has been constructed of stone, and a traveling crane was made and put up at the influent gatehouse of the distributing reservoir for use in handling the heavy stop timbers when the monthly measurements of water consumed and wasted in the city are made, and on other occasions when the flow into the reservoir is interrupted.

The United States mains, aggregating about 21 miles in length, which lead from the distributing reservoir to the city and supply the system of street mains that were laid by and are under the care of the authorities of the District of Columbia, are in excellent condition. Three breaks, none of them serious, occurred during the year. One of them was in the old 30-inch main in New Jersey avenue. The two others were in valves connected with the 48-inch main, and were the result of the unprecedented cold weather of the last winter. At Foun dry Branch the stem of the 30-inch blow-off valve was fractured while operating the valve. The renewal of this stem, which is a heavy gunmetal casting in the form of a screw and weighing about 150 pounds, required the emptying of the 30-inch and 12-inch mains between the distributing reservoir and Georgetown twice, once in order to get out the broken stem for a pattern and again to put in the new one.

The

The survey of the boundaries of the aqueduct lands, both in the District of Columbia and in Maryland, has been continued. By an act of Congress approved July 14, 1892, the Attorney-General, the Secretary of War, and the Engineer Commissioner of the District of Columbia were empowered to select from the lands in the District of Columbia belonging to the United States a site for a Girls' Reform School. Under the decision of the commission, a tract containing 19.39 acres, and comprising nearly the whole of the reservoir land lying between the Conduit road and the Little Falls road, was surveyed and exscinded from the reservoir lands for this purpose. Metropolitan Southern Railroad Company selected and surveyed its route through the lands of the receiving reservoir, as authorized by the act of Congress approved March 3, 1891. The location and plans of the road were approved by the Secretary of War, and regulations concerning the work of construction and the operating of the road have been prescribed by him. The value of the lands to be occupied by the railroad company was appraised by a board of officers, as directed in the act, and the amount of the appraisement was paid by the company and deposited in the Treasury.

The roadway over Bridge No. 4 (Cabin John Bridge) was temporarily repaired by filling the holes in the asphalt pavement with broken stone and earth, but this only made the bridge passable, and the pavement of this bridge, as well as that of Bridge No. 3 (Griffith Park Bridge), is still in very bad condition. An entire renewal of the wooden superstructure of the Pennsylvania Avenue Bridge over Rock Creek has been made.

In the list of estimates of the officer in charge for the fiscal year ending June 30, 1895, will be found estimates for the remainder, $90,000, of the amount contemplated by Congress in its act approved March 3, 1893, for the improvement of the receiving reservoir, commencing the widening of the macadam pavement of the Conduit road, and raising the heights of the masonry casings of the conduit manholes. The officer in charge renews his estimates for several necessary works, as follows: Removing the accumulation of deposits in the conduit; lowering the height of the cross dam at the distributing reservoir; protecting the inlet to the aqueduct at Great Falls; the purchase or condemnation of a site for a storage yard; cleaning out the distributing reservoir; widening and deepening the channel from the spillway at the receiving reservoir; repaving Griffith Park and Cabin John bridges; storehouse at Great Falls; protecting the conduit at Wasteweir No. 1, near Great Falls; inserting air-valves and blow-off valves in the 36-inch and 30-inch mains, and rebuilding the bridge over the channel from the spillway at the receiving reservoir.

Full explanations of the foregoing estimates, all of which have had my approval, may be found in the report of the officer in charge. This officer also suggests an important provision of law respecting appropriations for the Washington Aqueduct that is required to make them available until expended, like appropriations for river and harbor works, light-houses, etc., and not fiscal year appropriations as at present, and he states the reasons therefor, as well as for a small increase of $1,000 to the general appropriation for the preservation and repair of the aqueduct and its accessory works.

Both of these are of great importance, and the recommendations of the officer in charge in respect to them are concurred in.