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OFFICE OF PUBLIC BUILDINGS, GROUNDS, AND WORKS,
U. S. Capitol, Washington, D. C., April 6, 1869.

GENERAL: I have the honor to acknowledge the receipt of your letter of the 3d instant, inclosing a communication from the Hon. B. C. Cook, chairman of the Committee on the District of Columbia, together with a copy of a resolution of the House of Representatives, in relation to the present condition of the Washington aqueduct.

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The Washington aqueduct was originally projected upon its present general plan and location by Captain M. C. Meigs, United States Corps of Engineers. Its construction was begun A. D. 1853, on the 8th day of November. The engineers in charge have been as follows: Captain M. C. Meigs, from November 3, 1852, to July 17, 1860; Captain H. W. Benham, from July 17, 1860, to December, 1860; Lieutenant J. St. Clair Morton, from December, 1860, to February 22, 1861; General M. C. Meigs, from February 22, 1861, to June 18, 1862, when the supervision of the work was transferred by act of Congress from the War Department to the Department of the Interior.

Under the Department of the Interior the engineers in charge have been as follows: William R. Hutton, from June 18, 1862, to July 21, 1863; Silas Seymour, from July 21, 1863, to June 5, 1865; Theodore B. Samo, from June 5, 1865, to April 19, 1867, when the supervision of the work was transferred by act of Congress from the Interior Department to the War Department, and placed under the charge of the Chief Engineer of the army.

The departures that have been made from the original plans of Captain Meigs are as follows:

1. A dam of solid masonry at Great Falls, instead of an embankment of broken stone.

2. A connecting conduit around the lower end of the receiving reservoir.

3. Slope-wall facing for the inner slopes of the distributing reservoir, instead of facings of small broken stones.

4. Raising the dividing bank in the distributing reservoir to the full height of the outer banks, and the construction of a gate-house therein, so as to allow of the independent use of either section of the reservoir.

5. Excavating the bottom of the distributing reservoir to an additional depth of thirteen feet, so as to increase the purity of the water, and afford twice the amount of storage capacity.

The construction of the Potomac dam was begun in August, 1864, and continued until January, 1865. On account of no appropriation having been made by Congress until late in July, 1866, the work was not resumed until the 9th of August, when it was continued until December 20, and then suspended for the winter. The work was again resumed June 20, 1867, and continued until the completion of the foundation and superstructure masonry, December 20, 1867. The dam, as now constructed, extends from the Maryland shore to Conn's Island, a distance of 995 feet, and gives a head of six feet of water in the aqueduct, or a daily supply of about fifty million gallons. It is contemplated, ultimately, to build the dam entirely across the river to the Virginia shore, of sufficient height to insure a supply equal to the full capacity of the aqueduct, which is about eighty million gallons daily. During the construction of the Potomac dam the work was often damaged and interrupted by freshets, but since the completion of the foundation and superstructure masonry it has sustained no damage, and an examination made on the secoud instant shows that it has again successfully withstood the spring freshets of the Potomac and is in good condition.

It is well and substantially constructed in accordance with the terms of the contract.

The connecting conduit was begun in July, 1864, and the work continued until April 1, 1865, when, on account of no appropriation having been made by Congress until July 28, 1866, the work was suspended. It was resumed early in August, 1866, and prosecuted until its completion August 8, 1867, when the waters of Powder Mill Branch and the receiv ing reservoir were shut off, and the water of the Potomac, which, since • December, 1863, had emptied into the receiving reservoir, was turned into the new conduit. This work was substantially constructed and is in good condition, except Dalecarlia tunnel, which is constructed through loose rock that is not self-sustaining, and the roof is supported with timbers. An estimate of the cost of arching this tunnel was made and submitted to Congress October 1, 1867, and October 1, 1868. No appropriation, however, was made, and recently a number of the timbers which had been in place since 1864 decayed and broke, and a large mass of the loose rock fell from the roof and choked up the tunnel. If an appropriation for arching this tunnel had been made in 1867 this accident would not have happened. As more than three hundred feet of the roof are supported by timbers it is probable that, during the present year, other slides will occur and largely increase the estimated cost of arching. The embankments over the connecting conduit are washed by the waves of the reservoir, and an appropriation to protect their slopes with rip-raps has been asked for.

No appropriation has been made for the distributing reservoir since June, 1860, and no work has been done on it since June, 1864; since then it has been used, in its unfinished condition, for storage and filtering of water until last November, when an examination showed that its unprotected banks were very much worn by the waves, and that there was danger of their giving way; the water was, therefore, shut off from the reservoir and it was gradually emptied. The gate-houses in connection with it are all unfinished, and no work has been done on either of them since June, 1864.

Other portions of the Washington aqueduct are yet unfinished and are as follows:

At Great Falls, a part of tunnel No. 1 requires arching.

Stone bridges 1 and 2 require coping.

Stone bridges 3 and 4 require parapets and coping.

The roadway over the conduit (being used for a public highway) should be macadamized.

At Georgetown, the high-service reservoir should be finished.

The necessity of completing the unfinished portions of the Washington aqueduct has been fully shown in the annual reports of the engineers in charge, and detailed estimates of the cost submitted to Congress, as will be seen by reference to the accompanying reports, dated 1864 to 1868, inclusive.

The conduit, from Great Falls to the distributing reservoir, has a diameter of nine feet, with a fall of nine and a half inches to the mile, and can discharge into the reservoir, with the present height of the Potomac dam, over fifty million gallons of water daily. From the distributing reservoir the water is conveyed to Georgetown and Washington through two iron mains of twelve and thirty inches diameter respectively; these two mains have been taxed to their utmost capacity for several years, and there has been a constant complaint from the consumers of the deficient supply. The only remedy for this is to complete the distributing reservoir and lay another main of thirty or thirty-six

inches diameter from the distributing reservoir to Capitol Hill. The following is extracted from the first annual report of Captain Meigs, dated February 12, 1853:

"The mains leading from the reservoirs are, I think, enough for the present. In a few years it will be necessary to enlarge them. Then the twelve-inch can be taken up and relaid in the distribution of the city, its place being supplied by one of thirty-six inches."

Since December, 1863, the supply of water has been uninterrupted; the amount daily consumed is about twelve million gallons-less than one-fourth of the amount at present supplied by the conduit; the surplus, for want of mains to bring it to the city, is wasted at the several waste-weirs of the conduit.

The quality of the water consumed is similar to that in the river at the Great Falls. When the river is swollen during freshets the water in the city is muddy and impure; this will be the case until the distributing reservoir is completed.

In regard to the lands occupied by the Washington aqueduct I beg leave to refer to page 23 of my annual report, dated October 1, 1868, where a description of them will be found. The land at Great Falls was taken for the use of the Washington aqueduct by Captain Meigs in 1853. There has been paid for it a nominal rental of ten dollars and eightyeight cents per annum.

The road across the farms of Jackson, Collins, and Anderson, was taken for the use of the Washington aqueduct by Silas Seymour in 1863; no compensation has been paid.

The road across the farm of Wm. Brooke was taken for the use of the Washington aqueduct by Silas Seymour in 1863 or 1864. A verbal agreement was made that the United States should fence both sides of the road and buy the land at a fair valuation. One side of the road has been fenced and a yearly rental of twenty-five dollars has been paid.

In Georgetown the lot owned by Mrs. Mosher, and the lot owned by Mrs. French, were taken for the use of the Washington aqueduct by Captain Meigs in 1861; no compensation has been paid for either lot. The papers inclosed in yours of the 3d instant are herewith returned. I am, general, very respectfully, your obedient servant, N. MICHLER, Major of Engineers, Brevet Brigadier General U. S. A.

Brevet Major General A. A. HUMPHREYS,

Chief of Engineers, Washington, D. C.

OFFICE OF PUBLIC BUILDINGS, GROUNDS, AND WORKS,

U. S. Capitol, Washington, D. C., August 20, 1869. GENERAL: The following is a copy of a letter, dated on the 14th inst., which has been addressed to the Hon. Secretary of War by a committee on the part of the corporate authorities of the city of Georgetown, in relation to the probable extent of damage and injury, if any, that may be done the Georgetown or Virginia channel of the Potomac River by the repairs now being made upon the railroad bridge across it:

GEORGETOWN, D. C., August 14, 1869.

DEAR SIR: The undersigned, a committee on the part of the corporate authorities of the city of Georgetown, D. C., respectfully represent that, having been advised that certain repairs are being made upon the railroad bridge over the Potomac River, which may have the effect to impair and destroy the channel of that river so far as the port of Georgetown is concerned, and being desirous of ascertaining the probable extent of

such damage and injury from those most competent to give an opinion upon the subject, they request that you will cause an examination to be made for this purpose by the proper officers of your department, and the result communicated to the corporate authorities of our city.

Very respectfully, your obedient servants,

General JOHN A. RAWLINS, Secretary of War.

H. M. SWEENY, Mayor.
CHAS. F. PECK, Recorder, &c.
JOS. L. SIMMS.

The above letter was referred to me, with instructions to give immediate attention to the subject, and to report the result of my examination. In connection with this matter, I respectfully submit for your information the two inclosed letters, marked A and B. The first was addressed to the receiver of the Washington, Alexandria, and Georgetown Railroad Company, calling his attention to the plan being executed by said company for the repairs of the railroad bridge, and respectfully remonstrating against the adoption of it, believing that it would prove, during the winter and seasons of freshets, not only damaging to that bridge, as well as the one known as the Long or Potomac bridge, running parallel to it, but also, by further obstructing the bed of the river, tend to injure the main and only channel communicating with Georgetown. While the commercial interests of the latter place must ever be jealous of any encroachment or any obstructions which might prove even in the slightest degree detrimental to the channel, it is equally important that an unbroken communication by rail should be had between the North and South; but both interests can be conserved by adopting a liberal and comprehensive policy. The railroad company could have accepted other plans for the strengthening of certain spans of the bridge than the one adopted by piles, such as the one which is now being used in other spans of the same work; they might not all be equally economical, but would certainly prove equally efficacious, and at the same time remove all the cause of fear as to injuring the channel. The second letter, marked B, is in reply to the former In this the receiver states that the "piles now being driven in the southern channel of the river for the support of the five long spans of the bridge are only intended as a temporary means of strengthening the bridge to accommodate the demand of the public for immediate travel, and to be used as false works in the construction of a more suitable structure at that point, to be erected at an early day; various plans for which have already been submitted, but not yet fully decided upon." This reply I deemed perfectly satisfactory, and took no further action in the matter, although, to my mind, the repairs seemed to be of a decidedly permanent character, at least as much so as the bridge itself. The subject is now again brought to my attention by the questions submitted by the committee on the part of the corporate authorities of the city of Georgetown. Before proceeding to answer the inquiries, I have thought it advisable and interesting, as a matter of history, to examine all the laws, charters, plans, and estimates of the several bridges in the District, and under the control of the government, to ascertain whether any restrictions have been placed by legislative enactments upon the dimensions of their spans, the nature of the material to be used, the different sites for their locations, their approaches, their construction, and more especially whether any laws exist regulating the several conflicting interests of the respective bridges, and the ship channels passing through them; also, to ascertain in whom the power rests to preserve the navigation of both the Potomac and Anacostia Rivers.

one.

The following are the several acts and parts of acts relating to the