kept clear and free from obstructions; the fencing about Government property at the Great Falls, the two reservoirs, and aqueduct office were repaired and white-washed; at the receiving reservoir some recal pairs were made to the keeper's dwelling, including the renewal of cor nice, gutter, and down spouts. At the distributing reservoir the screens of the effluent gate-house, having been destroyed by ice, were renewed, and the domes of both gate-houses were repaired and painted. For the protection of the old dam across the Maryland Channel at the Great Falls about 850 cubic yards of riprap stone was placed as a backing. The security of the aqueduct requires that considerable work be done annually to the overlying roadway in order to prevent heavily laden vehicles from cutting through and injuring the arch of the conduit; to this end all ruts and holes are filled with broken stone as they develop and a macadam roadway is being gradually completed throughout the 'entire extent of road which overlies the conduit-the length of road so treated during the past year was about 16,700 linear feet, principally on the Great Falls division; the amount of broken stone used for that purpose being 4,682 cubic yards. The flooring of bridge spanning the waste channel at the receiving reservoir was renewed with 3-inch Geor gia pine. During the year three leaks appeared on the line of the Government mains, and were duly repaired, two of them being small affairs only, but the third a serious matter, as follows: 1st, in August, 1887, in the roadway a short distance west of the Aqueduct Bridge over the Poto mac, near Georgetown, which was found to result from an abandoned service-pipe that had been tapped into the 30-inch main; it was taken out and the main securely plugged. 2d, in November, 1887, at the College Pond crossing, the calking having been blown out of a joint in the 30-inch main. 3d, about 3 o'clock on the morning of June 29, 1888, a serious break appeared at the pipe-line crossing of Foundry Branch. the repairs of which required uninterrupted work through thirty con secutive hours, during which the supply of water in the city was reduced to a dangerously low limit; one entire section of the 36-inch mair, 12 feet long, was destroyed by this break and had to be removed: another section in the immediate vicinity was found cracked, but this section was easily and quickly repaired by banding. The speedy re pairs made on this occasion were rendered possible only by reason of measures that had been taken in advance, to have on hand spare joints. collars, bands, plates, etc., fitted to the size of the main, in readiness for instant application. The break appears to have been caused by the fact that this large main was at this point supported on timber sills which had rotted out and left the main, with its load of water, without proper support. The outflow of water from the distributing reservoir, as measured during the twenty-four hours ending at 6 a. m. June 23, 1888, was 29,115,774 gallons, being 2,237,350 gallons more than the outflow as measured about the same time in the year preceding. (See Table 1.) The water supply, as it passed the effluent gate-house of the dis tributing reservoir, was clear on 240 days, slightly turbid 16, turbid 52, and very turbid 58. (See Tables 2 and 3.) The water-level at the inlet to the aqueduct at the Great Falls has varied from a maximum of 2.5 feet (on February 26, 1888) to a minimum of 0.6 feet (on August 10, 1887) above the crest of the dam. (See Table 2.) The average water pressure for the year in the supply-mains at the crossing of Rock Creek, as reported daily at 9 a. m., was 29.93 pounds square inch; the maximum 9 a. m. pressure was 343 pounds, and minimum was (disregarding the exceptional and temporary reduc caused by the breaking of the 36-inch main) 28 pounds. The averpressure during 1887 was 31.03 pounds. (See Tables 2 and 4.) 'he following tables, from which the items above noted were deduced, | furnish more detailed information in relation to the same points: LE 1.-Showing hourly flow from distributing reservoir for the twenty-four hours ending June 23, 1888. The outflow during twenty-four hours, as measured in the latter part June, for the past fifteen years is as follows: E II.—Showing—for each day in the year—(a) condition of water at Great Falls, receivreservoir, and distributing reservoir; (b) height of water over dam at Great Falls; 9 a. m. pressure at Rock Creek. TABLE 3.-(Compiled from Table 2) showing number of days during which the water was clear or turbid at the places indicated. TABLE 4.-(Compiled from Table 2) showing number of days in each month is v.. *June 29, 18.5 pounds; June 30, 20 pounds; occasioned by break in 36-inch main. List of appropriations made for the Washington Aqueduct, with the date of act for the sem NOTE.-Reverted to the Treasury: 182.81, 2346.25, 38560.87, 435 cents, $1,109.87, $381.06, 781.334 total, $3,455.38. The balance, $3,961,701.62, being the amount expended to June 30, 1888. Since one-half of the amounts appropriated have been contributed by the United States and the other k by the District of Columbia. The money statement for the year ending June 30, 1888, is as follows. July 1, 1887, amount available..... July 1, 1888, amount expended during fiscal year. $20,000." 19, 021.94 20,000.0 |