quired Removing the piles from the water way of the draw span, and arranging the span so as to permit it to be opened for the passage of steamboats and other water craft. Alteration to be made and completed on or before July 20, 1891. Alteration has been made and completed. 12. Bridge across the Chicago River at Canal street, Chicago, Illinois.Notice, dated August 5, 1891, served on the mayor of the city of Chicago, Ill., September 5, 1891. Alterations required: To remove the present pivot pier, the protecting wings or bridge rests, and all other adjuncts to said pivot pier now in the stream and obstructing navigation, and to so reconstruct said pivot pier and to so alter and change the said bridge and the draw as to give a clear opening of 60 feet in width for the passage of vessels on each side of said pivot pier. The present pivot pier, the protecting wings or bridge rests, and all other adjunts to said pivot pier now in the stream and obstructing navigation to be removed within 3 weeks of the date (September 5, 1891) of the service of this notice. The said pivot pier to be reconstructed and the said bridge and the draw to be altered and changed, as described above, on or before the 1st day of May 1892. (See report of Board of Engineers, Appendix B B B 2.) 13. Bridge across the Kentucky River at Frankfort, Kentucky.-Notice, dated August 28, 1891, served on the president of the Louisville and Nashville Railroad Company, at Louisville, Ky., September 14, 1891. Alteration required: To raise the said bridge 10 feet, so as to make its clear height above the normal level of pool 4 of the Kentucky River 48 feet and 4 inches. Alteration to be made and completed on or be fore September 1, 1892. 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 C CC.) 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-WATER SUPPLY, DISTRICT OF COLUMBIA, ACT MARCH 2, 1889-INCREASING THE WATER SUPPLY OF WASHINGTON, D. C.-ERECTION OF FISHWAYS AT THE GREAT FALLS OF THE POTOMAC. Officer in charge, Lieut. Col. George H. Eliot, Corps of Engineers. 1. Washington Aqueduct.-The work of repairing the damage to the dam at Great Falls, done in the great flood of June 2, 1889, was completed early in the year. The flood carried away the 15-inch coping course and part of the next lower course from a total length of 1,103 feet, or 347 feet from the dam across the Maryland Channel and 756 feet from the dam across the Virginia Channel. The work of repair commenced June 6, 1889, and, as the condition of the river would allow (except after the end of the last fiscal year while waiting for the new appropriation), it was steadily and energetically carried on. The cost of repair was about $9,000. Early in July the officer in charge found that he was not able to keep the water in the distributing reservoir up to its proper height, and it was evident that there was something wrong in the conduit, either in the feeder at its head or in one of the numerous tunnels along its route. He had an examination made at the former place, and, the river being exceptionally low, there was head room in the conduit sufficient to enable the watchman to pass through it in a boat lowered down to the water in the gate-house from the gate house to the inlet from the river. It was found to be half full of deposits (logs, stumps, gravel, and mud), that must have gotten in in the flood just mentioned. Work of cleaning out the feeder of the conduit was started at 10 o'clock a. m. on the 21st of July and carried on with a force of 32 men without stopping until its completion at noon of the 22d. While the water was drawn from the conduit the officer in charge had the conduit carefully inspected from the gate house to culvert No. 2, a distance of 9,300 feet. From 6 inches to 8 inches of sediment was found at the bottom of the conduit, but no obstruction except a telegraph pole about 20 feet long, which was found in the waste-weir No. 1. This and the débris found in the feeder to the conduit were doubtless drawn in from the river during the flood of 1889, and they show the danger to which the head of the conduit is subject in such floods. On the 12th of September, when the water was turned on the 12-inch main between the reservoir and Foundry Branch, which main had been used as a drain during the construction of the 48 inch auxiliary connection, there was found to be almost a complete stoppage of the flow between the reservoir and Foundry Branch. On making an examination of the main, there were found to be some small obstructions just above the blow-off at Foundry Branch, which were removed, but their removal did not relieve the main. Repeated emptyings and fillings of the main and every expedient that could be thought of were used to locate and remove the difficulty, but it was December before the full flow of the main could be obtained. The numerous trees growing over and near the conduit between Great Falls and the receiving reservoir, especially between the former and the "Club House," endangered the conduit by the penetration of their roots into the joints of the arch, and they were all cut down, the trunks of such as were suitable being saved for posts for use in fencing the aqueduct lands. A brick storehouse 40 feet by 20 feet in area has been constructed at the distributing reservoir for the storage of tools and materials for repairs on that division of the aqueduct, and it is proposed during the next fiscal year to erect a similar one at Great Falls for the upper division. The old office building at the receiving reservoir has been put in repair to serve the same purpose on the receiving reservoir division. Strong guard fences have been built on the sides of the conduit road at the dam at the receiving reservoir and at the high embankments at the culverts and other places between the distributing reservoir and the receiving reservoir. These were made necessary by the great increase of travel on the conduit road and the danger of accidents, especially at night. Four thousand two hundred and sixty-six feet of these fences was built during the fiscal year, and it is proposed during the next fiscal year, as funds will allow, to protect the embankments farther up the line. The road between the "Club House" and Great Falls, which is the only route of communica tion with the falls, and is almost impassable in winter, was macadamized for a length of 1,548 feet and a width of 10 feet on the worst portion of the road, and it is hoped to improve more of it during the next fiscal year. A new "curtain" screen for the screen-house at the distributing reservoir was completed during the year. In August a survey was made of the land owned by the United States between Foundry Branch and the distributing reservoir. There were found to be several cases where parties owning the adjoining land have built fences on the lands of the United States and several cases where private improvements were found to encroach on these lands. Authority has been given the officer in charge to employ the District surveyor to make an accurate survey of the lands surrounding the receiving reservoir. The survey has been completed and the lines will be permanently marked. During the next fiscal year it is proposed to continue the surveys of the lines of the aqueduct lands and to place boundary stones at all the angles where they are missing. With the approval of the Secretary of War, there have been turned over to the Commissioners of the District of Columbia, for care and maintenance, 131 valves which were placed on the outlets from the 48-inch main and the connecting mains recently laid under the act of March 2, 1889, for controlling the supply of water from these mains to the District's distributing mains. The other valves on the former mains, 98 in number, in addition to the valves on the old mains, remain under the care of the officer in charge of the aqueduct. A contract has been made for the delivery of 5 iron-pillar cranes for handling the stop timbers on the line of the aque duct. The opening from conduit tunnel No. 1 at waste-weir No. 1, near the head of the conduit, one of the most important of the waste weirs, is exposed to an inflow from the river in great floods like that of June, 1889, when the river rose 75 feet at this point, and to an indraft of logs and other drift wood, which endangers the conduit and the supply of water in the city. It was intended to make the required repairs and alterations at this place during the last fiscal year; but, as it is impossible to get materials for the purpose to the weir except by the Chesapeake and Ohio Canal, the work has been postponed until the next fiscal year, when it is expected the canal will again be in operation. There is a leak in the conduit at the upper end of Cabin John Bridge, the repair of which will also have to be postponed until the repairs of the canal are completed. In order to repair the leak the conduit will have to be emptied the entire distance from Great Falls to the receiving reservoir, and it is proposed at the time of the repair to take advantage of the opportunity and have the interior of the conduit inspected from one end to the other. The tar pavement of the roadway over Cabin John Bridge is badly worn, and it is proposed to repave the bridge with granite blocks. The officer in charge recently obtained the details of a patented device for tapping, with taps up to 12 inches in diameter, large mains under pressure; that is, the shutting off of the water, which is always a source of anxiety on account of the danger in case of fire in the district supplied by the main, can be avoided when the main is tapped. In the report for the last fiscal year mention was made of a great deficiency of air-valves and blow-offs on the old mains, which it is hoped to supply during the next fiscal year by the use of this device. In the act of August 6, 1890, making appropriations for the Washington Aqueduct, the sum of $1,000 was appropriated for the purchase of 5 acres of land near the distributing reservoir, and $1,500 was appropriated for the improvement of this land, but by reason of a rise in the asking prices of land in the vicinity the trustees of the owners would not sell the piece desired for less than $3,000 an acre, or $15,000 for the whole, and a resort to condemnation was, under the circumstances, not deemed advisable. Fortunately the Drover's Rest cattle market has been discontinued and all of the buildings and fences have been removed, so that the necessity of the purchase no longer exists, althongh it would be desirable for the United States to own the entire frontage on the northerly side of the conduit road opposite the distributing res ervoir. There have been no breaks or any serious leaks in any of the mains during the last fiscal year. The bank of Rock Creek was wearing so much under the action of the 20-inch blow-off from the 48-inch main which passes out through the west wing wall of the M street highway bridge, that it would endanger the foundation of the wall, and a large flume of lumber was constructed to carry the outflow from the blow-off to the creek. It serves the purpose temporarily, but it will be necessary to extend the pipe outlet from the blow-off to the edge of the creek, and it is proposed to do this in the next fiscal year. The construction of the cable railway of the Washington and Georgetown Railway Company on M street, Georgetown, has made it necessary to remove the arches of two of the three valve chambers which occupy nearly the full width of the street between Twenty-ninth and Thirtieth streets, and replace them by I beams and arches of small span and rise. The work has been done at the expense of the railway company under supervision of the officer in charge of the aqueduct. Last year, when the water in the river was at its low stage, or between 6 inches and 1 foot over the dam at Great Falls (which it was for several months), it was found that the water in the distributing reservoir could not be kept up to its proper height of 146 feet above datum. The same is found this year, and that when the water in the distributing reservoir is lowered about 2 feet during each of the monthly measurements of the consumption and waste of water in the city, it requires about 4 days to get the water in the reservoir back again to its height. The reason of this is that the height of the dam at Great Falls is not sufficient at low stages of the river to keep the conduit full at its head, or to enable it to deliver as much water as is now consumed and wasted in the city, and at the same time to keep up the head in the mains at the distributing reservoir to 146 feet above datum, which is necessary for the supply by gravity of the high northern portions of the city and of Capitol Hill. The only remedy for this (and it is one that should be made before any further steps are taken for increasing the supply from the distributing reservoir to the city) is the raising of the dam at Great Falls nearly if not quite 23 feet, or to the height of 1505 feet above datum. During the past year, in addition to the work that has been specifically mentioned, the usual operations for maintaining and preserving the aqueduct have been carried on, and much other work, of which the details will be found in the report of the officer in charge, has been done. In the table appended to the report of the officer in charge will be found the details of the measurements of water consumed and wasted in the 24 hours ending June 25, 1891, the monthly measurements during the last fiscal year, and the annual measurements in June of each year from 1874 to 1891, both inclusive. The average consumption and waste per diem is 36,588,629 gallons, or about 1,000,000 gallons more than the measurement in 1890, which was taken soon after the 48-inch main was completed and put in operation. The average annual increase before the introduction of the 48-inch main (or from 1874 to 1889) was about 677,000 gallons. From the result of the census of 1890 very close calculations of the consumption and waste of water per capita have been made, taking first the area actually supplied with Potomac water, and also the entire population of the cities of Washington and Georgetown. The results and a comparison with former census years will be found in the report of the officer in charge. Attention is invited to the remarks of the officer in charge respecting the necessity of appropriation for the additional works required for restoring to use the receiving reservoir for the double purpose of improving the quality of our Potomac water by relieving it of the muddiness that it has in winter and spring, and of regaining the storage capacity that was lost when this important reservoir, which has a capacity of about 175,000,000 gallons, was thrown out of service by reason of the pollution by some small streams that lead into it; for the further improvement of the quality of the Potomac water by lowering the height of the cross dam at the distributing reservoir; for the protection of the inlet to the aqueduct at Great Falls; for extending an important waste-weir, which is liable to be obstructed by the private owners of adjacent land; for cleaning out the distributing reservoir, and for the purchase or condemnation of a site for a storage yard for supplies for use in case of breaks in mains. These objects and the desired general provision of law relating to appropriations for the Washington Aqueduct are of great importance, and the recommendations of the officer in charge in respect to them are concurred in. Attention is also invited to the remarks of the officer in charge respecting the necessity that will soon arise of raising the height of the dam at Great Falls to meet the growing demands on the aqueduct. The following is a money statement for the fiscal year ending June 30, 1891: July 1, 1891, amount covered by uncompleted contract Amount of appropriation of August 6, 1890, to be reverted to the Treasury.. 2,510.00 5,500.00 9, 444. 25 July 1, 1891, balance available 20,000.00 The estimate of the officer in charge for the fiscal year ending June 30, 1892, are as follows: For improving the quality of the Potomac water and restoring the capacity for its storage, by improving the receiving reservoir, including the purchase or condemnation of the necessary land. For further improving the quality of the Potomac water by lowering the $290, 625 12,500 5,000 2,500 For purchase or condemnation of a site for a storage yard For maintenance and repairs of the aqueduct and the reservoirs, mains, (See Appendix D D D 1.) 10,000 13, 825 21,000 355, 450 |