W 11. Annual report for the breakwater at Wilmington, California, for the year ending the 30th June, 1871. SAN FRANCISCO, CALIFORNIA, July 31, 1871. Under the instructions of the Engineer Department, dated the 224 March, 1871, an examination and partial survey of the harbor of Wilmington was made in the months of April and May. A report and plan for the proposed improvement of the harbor, based upon the results of this examination, was submitted on the 15th June. Under date of the 1st July the project was approved in part by the Chief of Engineers, and orders given to contract for the first division of the line, about 3,630 feet in length. By subsequent telegraphic authority from the Chief of Engineers, dated the 14th July, engagement was made in open market for the timber, to be delivered at San Pedro anchorage. By the same authority, bids have been invited for the construction of this first division. These bids will be opened on the 14th August, and the work advertised is to be completed by the 1st day of March, 1872. After this part of the construction is inaugurated, preparations will be made to construct the remaining portion so far as the available funds will permit. Respectfully submitted. G. H. MENDELL, Major of Engineers. Washington, D. C. The CHIEF OF ENGINEERS, U. S. A., APPENDIX X 1. OFFICE OF WASHINGTON AQUEDUCT, GENERAL: I have the honor to make the following report for the last year concerning the Washington Aqueduct : THE DAM AT GREAT FALLS. The permanent dam extending across the Maryland channel, or from a point near the head of the aqueduct to Conn's Island, remains in excellent condition, and has required no repairs during the year. There was an appropriation of $5,500, available for expenditure during the last fiscal year, for removing the obstructions in the river above the dam, which prevented the free access of the water to the head of the aqueduct. These consist of some low, grassy islands and rocks, and ledges. When I took charge of the aqueduct, in November last, there was a party of workmen engaged at this point, but the water in the river, soon after, had risen so much that the work could no longer be prosecuted to advantage, and I suspended operations at this point till the low water of the present season. On the 15th of July the water had subsided so that work could be resumed, and it will be continued till the appropriation is exhausted, unless high water should interfere. It is believed that the work done and to be done, under the appropria tion, will effectually remove the difficulty which existed, and that the supply of water to the aqueduct will be sufficient for many years, and for a large increase in the population of the District. Before the full capacity of the conduit, nearly 100,000,000 gallons per day, (a supply sufficient for a population of more than half a million, besides furnishing a great amount of water-power,) can be realized, an extension of the dam across the Virginia channel, according to the original design, will probably be necessary. CABIN JOHN BRIDGE. My estimates for the parapets of this bridge, Griffith Park Bridge, and the two others on the line of the conduit, were $20,000, but Congress reduced the amount in the appropriation to $10,000. The coping for this bridge has not been laid, and it is necessary before any kind of a parapet or railing is placed. The appropriation is for "completing coping and iron railing," but it is not sufficient for even an iron railing of the strength required for the narrow and elevated roadway over the bridge. I recommend that the coping be purchased and laid with the existing appropriation, and that the balance be retained in the hope that Congress will grant an additional amount. An iron railing is not suitable for this bridge, which is much used by the heavy teams from Montgomery County, and is so narrow that there is barely room for two to pass each other. I have designed an open-work brick parapet, to be covered with stucco, which will not cost more than a heavy iron railing, and will be in keeping with the character of this elevated structure. The roadway is but 14 feet wide, and is 90 feet above the creek, and the parapet should not only be strong enough to prevent accidents in cases of horses becoming frightened on the bridge, but should have the appearance of strength which an iron railing, liable to be struck by the hubs of wheels of vehicles, would not have. Probably the parapets should be of stone to be commensurate with this celebrated bridge. THE TUNNELS ON THE LINE OF THE CONDUIT. Tunnel No. 1 (near Great Falls) is not lined by an arch, and some rocks fell some years ago from the roof to the floor, and they interfered somewhat with the waterway. There is an appropriation of $1,500 available for their removal, but the supply by the conduit to the District could not well be interrupted up to the present time on account of the work at the reservoirs, and the water has not yet been drawn off, which is necessary for the removal of the rocks. As soon as the storage reservoirs are completed, and the supply from the river can be stopped for a few days, these rocks will be removed. The other tunnels are all in good condition. THE CONDUIT. The conduit remains in excellent condition. In February last I raised the water in the distributing reservoir to the height of 145 feet above the datum level, or to the flow-line of the reservoir as originally designed This produced a pressure on the soffit of the conduit arch, (of three feet of water at the effluent end,) and, as was to be expected from the unequal character of the foundations of the conduit, there were some small leaks discovered where it rests in embankment. These were repaired with cement, and no trouble has since been discovered. There was an appropriation of $10,000 for the fiscal year 1870–71 for macadamizing the conduit road, to prevent the traffic, which is considerable, between Montgomery County, Maryland, and the District, from cutting through the earth and injuring the extrados of the arch. Under this appropriation there were macadamized 16,872 running feet of the road, and stone was hauled and distributed along the road sufficient to macadamize about 2,800 feet more. In addition to the macadamizing, there was a large amount of work done in raising and widening the embankment over the conduit. There was made, by act of March 3, 1871, a further appropriation of $10,000 for continuing this work, which is now in progress, and it is believed that it will protect all of the road which requires any expenditures upon it. THE DALECARLIA TUNNEL. The arching of this tunnel, which connects the conduit above with the conduit below the receiving reservoir, and was constructed so that the daily supply of water could be led from the Potomac directly into the city or into the distributing reservoir whenever the water of the receiving reservoir is turbid, or otherwise unfit for use, (which it sometimes is after storms on account of its being surrounded by cultivated hills,) was in progress by my predecessor when I took charge of the aqueduct, and soon after that date was finished. THE RECEIVING RESERVOIR. The balance of the appropriation available for the protection of the banks of the reservoir will be expended as soon as the other works now on hand will permit, in constructing the wing-walls at the outlet of the conduit into the reservoir, and if any money should remain when these are completed, it will be expended on the water-face of the dam. This reservoir will then be completed. On the 20th of June last, the fetid taste and smell of the water consumed in the District attracted the attention of every citizen. It remained for several days, and passed off as mysteriously and as rapidly as it came. It is not an unusual circumstance in water-works, but the causes of it do not seem to be very well understood. The generally received opinion is, however, that it arises from the confervæ which, under favorable circumstances, are generated in all reservoirs. The large area of shallow water in the receiving reservoir conduces to their growth, and it and the turbid condition of the water after showers, arising from several small streams which flow into it, and from the cultivated ground around it, render this reservoir unreliable as a source of supply, and as a rule the water from the Potomac should flow through the Dalecarlia tunnel, and not through this reservoir. It is frequently the case, however, when the water of the Potomac is turbid, that the reservoir is clear, and it will always be required for storage purposes, to be used from in case of accident to the works above, or of the impure condition of water in the Potomac. Under an act of Congress approved by the President on the 6th of May, 1870, the lands about the reservoir, or so much of them as were not required for the purposes of the aqueduct, were to be set off for the use of the Reform School. The boundaries of the lands to be set off have been surveyed, and as soon as the plat can be copied it will be transmitted for the approval of the War Department. THE DISTRIBUTING RESERVOIR. Work on this reservoir was commenced on the 13th of April last. Contracts were made at reasonable prices for the slope-walls for the protec tion of the dams, and for the labor necessary to put the latter in condition to receive the walls. The reservoir has been used for some years without any protection to the dams, and they had become much washed by the waves, so much so that the eastern dam had been nearly onehalf washed away. There have been about 2,796 cubic yards of slopewall and its broken-stone foundation laid by the contractors, and there are about 5,888 yards yet to be laid by them. The houses for the watergates are under construction, and the entire reservoir will be finished by the time the contractors have completed their contract for finishing the slope-wall. The public land at this reservoir will be fenced, trees will be planted outside the dams, the tops and slopes of the dams will be sown in grass, and it is believed that this will soon be one of the most attractive spots in the District. THE HIGH-SERVICE RESERVOIR IN GEORGETOWN. The appropriation for this reservoir was, for the fiscal year 1870-271, $4,000, and for the fiscal year 1871-72, $4,000. Plans were prepared for an ornamental iron cornice at the top of the unfinished domical arch over the reservoir, and for an iron fence around the lot, when I received a petition from citizens in the neighborhood that the dome be taken down and an iron fence be built upon the reservoir wall. The top of the reservoir, as designed, would require the dome to be completed to the top, following the rule in Europe of covering reservoirs in cities to protect them from the sun, and especially from the dust from the streets. My design is a compromise between the wishes of the citizens in the neighborhood and the original, and I am convinced that, when it is finished, the reservoir will be an ornament to that part of Georgetown, and the objections of the protestants will be removed. As soon as the iron-work is finished, the exterior of the arch will be covered with stucco. PURCHASE OF LANDS. The following sums have been paid during the last year for lands which have been used for some years by the United States for aqueduct purposes, and in all cases they include the rents that had accrued : For two lots of land at the high-service reservoir in Georgetown.... $3,300 00 For 5.44 acres of land at Great Falls. 1,320 00 For 18,581 square feet of land at the tubular aqueduct bridge across Rock Creek........ 2,639 98 342 55 For 1.66 acres of land near the receiving reservoir. There was also appropriated, by act of Congress approved 15th July, 1870, $1,012 for the purchase of roadway between the head of the conduit road and the Great Falls, but the owners, with one exception, were so unreasonable in their demands that the purchases were not completed before the 1st day of July last, at which date the balance of the appropriation lapsed into the Treasury. THE NEW 36-INCH MAIN FROM THE DISTRIBUTING RESERVOIR TO CAPITOL HILL. The laws of Congress in relation to this are as follows: SEC. 6. And be it further enacted, That whenever it shall become necessary to lay main pipes for the supply to the cities of Georgetown and Washington, the cost of the same shall be paid by the said cities, and the engineer aforesaid is hereby prohibited from making any contracts for the same, unless approved by the corporations aforesaid, and expressly stipulated with the contractor or contractors that the payment for the same is to be made by the said corporations. Approved by the President March 3, 1859. SEC. 4. And be it further enacted, That the said engineer officer shall cause to be furnished and laid, from the distributing reservoir of the Washington Aqueduct to Capitol Hill, in the city of Washington, along such route as he shall determine, an iron inait of 36 inches in diameter, connected with the present maius, at such points as he shall direct, and that the entire cost thereof shall be borne apportionately by the corporations of Washington and Georgetown; and in order to provide for such cost, the said corporations are hereby empowered and authorized to increase the present water-raies and water-taxes to such an amount as may by them be deemed necessary. SEC. 5. And be it further enacted, That for the purpose of enabling the corporations aforesaid to carry out the provisions of this act, it shall be competent for them to borrow, in such proportions as they may deem necessary, a sum of money not exceeding two hundred and sixty thousand dollars for the city of Washington and forty thousand dollars for the city of Georgetown, redeemable within a period of ten years out of any revenue to be derived from water-rents. Approved by the President July 14, 1870. The attention of the governments of Georgetown and Washington was brought to this matter by letter and estimate which I submitted on the 13th of January, 1871. But no appropriation was made till the new territorial government passed the act of July 20, 1871, appropriating $450,000 for this main, for a 30-inch main on New Jersey avenue, and for a 20-inch main on Capitol Hill. The specifications and drawings having been made, invitations for proposals for furnishing the 36-inch main from the reservoir to New Jersey avenue (which will require about 9,000,000 pounds of iron) were invited by circular and advertisement on the 24th of July last. The bids were opened on the 15th of August. It being found that the lowest bid (though made in good faith and though the contract was claimed under it by the bidder) was informal, I referred the question, as to my power to accept it, for the decision of the Attorney General of the United States. That officer having decided that I could not accept the lowest bid, and the difference between it and the next bid being so great, (about $25,000,) I determined, after conference with Governor Cooke, to reject all the bids and readvertise, which I did on the 25th ultimo, and bids were opened anew on the 5th instant. Considering the disappointments and delays in the furnishing of pipe to those cities which had no recourse for damages except by means of suits on the bonds of the contractors, and the urgent necessity of an immediate increased supply, I gave notice in my readvertisement that I should provide in the contract, in addition to the bond, a penalty of one dollar a day for each and every pipe not delivered on the 1st of February next, to be deducted from any moneys due the contractors. On the second opening of bids there were four which, considering the estimated quantities, amounted to the following sums: Jesse W. Starr & Sons, Camden, New Jersey. William Smith, Pittsburgh, Pennsylvania... R. D. Wood & Co., Philadelphia, Pennsylvania.. The Gaylord Iron Pipe Company, Cincinnati, Ohio.................. $284,926 07 285,064 82 288,050 10 301, 633 10 The award was made, with the approval of the governor, to the lowest bidders. Invitations for tenders for laying the pipe having been advertised, the latter were opened on the 15th instant. There were twelve bids, the lowest being those of Emmart, Dunbar & Co., (for the reservoir, the east and the west Washington divisions,) and ́ O'Hare, Himber & Co., (for the Georgetown division,) at prices which, considering the estimated quantities, amount to $61,801 50 for the whole line. The awards having been made to the parties just named, they have |