NECESSITY FOR INCREASING THE MEANS OF SUPPLYING WATER FROM THE DISTRIBUTING RESERVOIR TO THE CITY. The completion of the work of raising the dam at Great Falls and removing deposits from the conduit marks the conclusion of all operations of magnitude necessary to develop the maximum flow of the conduit. The recent current-meter observations show that this maximum flow, provided the distributing reservoir is not allowed to fall more than 2 feet below its present level, is about 76,500,000 gallons in twenty-four hours or about 31,000,000 gallons per day more than the present daily consumption-a very satisfactory condition of affairs so far as this part of the system alone is concerned. For several years the trunk mains leading from the distributing reservoir to the city have been overtaxed and their limit of efficient flow has already been reached. Every additional increase in the volume of flow through these mains will be marked by a rapid decrease in pressures in those parts of the city supplied by gravity alone. It therefore is seen that the aqueduct system is capable of bringing to the distributing reservoir daily about 31,000,000 gallons more water than it can efficiently supply to the city from that reservoir. Consumers of Potomac water will experience but little practical benefit from the completion of the work of raising the dam and removing deposits from the conduit until some method is provided for bringing an additional supply of water from the distributing reservoir to the service mains of the city. A commission of experts appointed by authority of the Secretary of War in November, 1895, reported that the completion of the unfinished tunnel between the distributing and Howard University reservoirs furnished the most economical method "for bringing increased water supply from the reservoir in Georgetown to Washington by pipes or otherwise." In accordance with this report I therefore submit in the proper place an estimate for resuming and completing work upon the Aqueduct Tunnel and the new reservoir near Howard University. EXPLANATION OF ESTIMATES. Repairing north connection of by-conduit, Dalecarlia Reservoir.-Should the water in the Dalecarlia Reservoir ever become so polluted from any cause as to render it unfit for drinking, the total supply for the city would have to pass through the by-conduit, which is now in such bad condition at its upper end as to permit the free interchange of its waters with those of the reservoir. In view of the completion of the excellent system of protection works around the reservoir, contamination through drainage from the surrounding watershed seems a very remote contingency, yet should it ever occur the consequences, in the present condition of the by-conduit, would be so grave that it is unquestionably the part of wisdom to keep this by-conduit always in as good condition as its faulty construction will permit. It is believed that the north end of this by-conduit can be repaired at a cost not to exceed $3,000 and an appropriation of this amount for the purpose specified is recommended. Repairing the conduit road.-Travel upon this road is increasing so rapidly every year that it is impossible to keep it in proper condition out of the present appropriation, without detriment to other more important parts of the aqueduct system. The road, however, forms so popular, useful, and beautiful a highway, that its condition should be improved from year to year, rather than allowed to deteriorate as inust of neces sity be the case if the road must be kept up solely from the very limited appropriations for the operation, maintenance, and repair of the Washington Aqueduct. I therefore urgently recommend that hereafter an annual appropriation of $5,000 be made for the specific purpose of repairing the conduit road, the care of culverts, ditches, slopes, etc., to be paid as heretofore from the annual appropriation for the Washington Aqueduct. Completing the Washington Aqueduct tunnel and new reservoir.—As previously explained, the Washington Aqueduct is now capable of delivering into the distributing reservoir in Georgetown, at its maximum discharge, about 31,000,000 gallons per day more than the overtaxed trunk mains can efficiently carry into the city. A commission of experts appointed by authority of the Secretary of War in November, 1895, reported that the completion of the unfinished tunnel between the distributing and new reservoirs furnished the most economical method "for bringing increased water supply from the reservoir in Georgetown to Washington by pipes or otherwise." The completion of this tunnel will necessitate that of the new reservoir. In view therefore of the report of the commission of experts already alluded to, it is recommended that the sum of $805,850.30 be appropri ated for resuming work upon and completing "the tunnel between the distributing reservoir and the new reservoir near Howard University, and for the other works connected therewith, including the latter reservoir." In connection with this subject it is proper to invite attention to the fact that over $290,000 of the appropriations made by the act of 1882 and by subsequent acts for "increasing the water supply of Washington, D. C.," remains unexpended in the Treasury of the United States. This sum also should be made available for the purposes just indicated. Storehouse and stable.—A combined storehouse and stable is urgently needed at Great Falls. The present building used for that purpose is a mere wooden shell, old, decaying, unsightly, and insecure, and affords neither adequate shelter nor protection to the valuable Government property stored at the Falls. I therefore urgently recommend an appropriation of $3,000 for the construction of a combined storehouse and stable of brick, with slate roof. In previous annual reports recommendations have been made and estimates submitted for certain works necessary for the preservation and repair of the Aqueduct system. In these recommendations and estimates I heartily concur, and the explanation for their necessity and the estimates of their cost are consequently restated. Storage yard. The storage yard on the bank of Rock Creek, in rear of and pertaining to the Aqueduct office, is entirely unsuited to the purpose. It is too low, and the route from it to the level of the street being steep and tortuous, before the very heavy castings required for repairs could be hauled out much damage and destruction of property might be done. A portion of these supplies has been placed in a yard at the distributing reservoir for use in the country portions of the routes of the mains, and the remainder, for use in the city portions of these routes, has been placed in a portion of Twentyseventh street, near M Street Bridge, which has been loaned for the purpose by the District government until the street is wanted for further improvement. When this occurs this office will be without a storage yard and one should be purchased as soon as possible. It should be near the office and at or near the grade of the street, so that the heavy castings and machinery needed for repairs can be quickly gotten out. It is believed that a suitable lot can be obtained by purchase or condemnation for $10,000, and an appropriation of this amount for the purpose specified is recommended. Protection of the inlet to the conduit at Great Falls.-The bank of the Chesapeake and Ohio Canal, which runs parallel to the Potomac at Great Falls, and about 150 feet from it, is about 14 feet higher than the uncovered chamber just above the Maryland end of the Aqueduct Dam that forms the inlet from the river to the conduit. In the flood of November, 1877, which rose at Great Falls to the height of 160 feet above the datum of the Aqueduct, or 12 feet higher than the crest of the dam, the canal bank at a point opposite the inlet was washed down to the river and a part of it into the inlet. I quote from the annual report of the Aqueduct for 1878: "The masonary forming the arch of the feeder was uncovered from a point near the middle of the canal to the mouth of the feeder, a distance of 150 feet. The chamber at the head of the Aqueduct was filled with stones that had formed the slope wall of the canal, and the Aqueduct feeder for a distance of 300 feet was filled with débris to depths varying from 3 to 6 feet, so as to entirely stop the flow of water during the ordinary low stages of the river." In the still higher flood of June, 1889, which rose to the height of 16 feet over the Aqueduct Dam, the canal bank was again washed down to the river, but fortunately the damage did not occur immediately opposite the inlet to the conduit, but from 200 to 400 feet higher up, so that the major part of the débris being left on the margin of the river and a part of it being carried over the dam, not so much filling of the inlet to the conduit was done, but, as in the flood of 1877, it was partially obstructed. The annual report of the Aqueduct for 1889, says: "The banks of the Chesapeake and Ohio Canal above and below the mouth of the conduit were carried away and that opposite the conduit was threatened. A number of men were kept at work on this bank during the freshet, and it is believed that had it not been for the energetic work of this force and the widening and strengthening of the bank at this locality in April, great damage would have occurred at the mouth of the conduit." It will be observed that in the freshet of 1877, not only the inlet chamber, but the conduit itself was filled with débris to a depth of from 3 to 6 feet for a distance of 300 feet in from its mouth, but, the water in the river being at a high stage, there was still waterway enough in the conduit above the débris to enable the supply to the city to be kept up. Had a complete closure of the mouth of the conduit occurred, with 12 to 16 feet of water over it, there would have been no possible way, with the torrent raging over the mouth, to remove the obstruction before the river subsided, and the water supply to the city would have been cut off. There is no more important part of our system of water supply to be carefully guarded than the head of the conduit at Great Falls, and in order to avert dangers like those of 1877 and 1889, to which the water supply is liable at every freshet, a masonry wall should be built between the river and the canal, rising a few feet higher than the latter and extending up river from the mouth of the conduit as far as the limit of the Government land, and thence, at about a right angle, and still on the Government land, to the shore of the river. The estimated cost of this wall is $5,000. Annual appropriation for operation, maintenance, and repair of the Aqueduct system.-Owing to the experience gained during the two preceding years, it is now known that it is entirely practicable to remove all deposits from the Aqueduct and to scrape and sweep the interior thoroughly once every year at comparatively small cost, and it is proposed to carry out this plan annually hereafter. In order to do this no increase over the regular annual appropriation of the preceding year is deemed necessary, and I therefore recommend the appropriation of $21,000 for the preservation, maintenance, and repair of the Washington Aqueduct, a sum which is but one-half of 1 per cent of the cost of the works. APPROPRIATIONS AND DEPOSITS. By act approved March 3, 1897 (Public-No. 129), there were appropriated for Washington Aqueduct. For engineering, maintenance, and general repairs.. $21,000 5,000 A project for the expenditure of these appropriations was submitted on May 25, and approved by the Chief of Engineers on May 27, 1897. The work will be accomplished during the fiscal year commencing July 1, 1897. By direction of the Secretary of War and to cover any damages to the property of the Aqueduct system, the following sums were deposited with the Treasurer of the United States to the credit of the Washing ton Aqueduct: November 23, 1895, by Metropolitan Railroad Company. June 12, 1896, by Capital Traction Company.. June 19, 1896, by Glen Echo Railroad Company. June 22, 1896, by Washington and Great Falls Electric Railway Company. $500 500 500 500 It has not been necessary to expend any of this money for the purposes contemplated, and by order of the Secretary of War the deposit made by the Glen Echo Railroad Company was returned to the company on May 25, 1897. ESTIMATES. The estimates of appropriations that should be made for the year ending June 30, 1899, are as follows: For repairing the north connection of the by-conduit, Dalecarlia Reservoir. $3,000.00 For repairing the Conduit road.. For resuming work upon the Washington Aqueduct tunnel and new res- For building combined storehouse and stable at Great Falls For operation, maintenance, repair, etc., of the Aqueduct and its acces- Total.... Money statements. July 1, 1896, amount appropriated by act of June 11, 1896................ July 1, 1897, balance unexpended. July 1, 1897, balance available.... Amount that can be profitably expended in fiscal year ending June Submitted in compliance with requirements of sections 2 of river and July 1, 1897, balance unexpended.......... 5,000.00 805, 850.30 3,000.00 10, 000. 00 5,000.00 21,000.00 852, 850.30 $20,000.00 19, 338.92 661.08 618.35 42.73 *852, 850.30 INSERTING VALVES. $5,000.00 4,758. 68 241.32 Appropriations made for the Washington Aqueduct, with the dates of acts for the same. NOTE.-Reverted to the Treasury: (a) $2.81, (b) $46.25, (c) $560.87, (d) 35 cents, (e) $1,109.87, (f) $381.06. (g) $1,354.17, (h) $2,266.34, (i) $4.12, (j) $5,500, (k) $2.49, (m) $39.96, (n) $2,983.87, (o) $285.85, total, $14,531.08. Since 1878 one-half of the amounts appropriated has been contributed by the United States and the other half by the District of Columbia. * $805,850.30 of this amount is for resuming work upon the Washington Aqueduct tunnel and new reservoir and their accessories. |