Imágenes de páginas
PDF
EPUB

In addition, there has been constructed a transfer slip and railway to facilitate the distribution of material removed from the river.

It consists of a railway of standard gauge, about 1,300 feet long, and 8 feet above high tide, built on a pile causeway with an incline to the river, on a grade of about 2 per cent, where it will connect with a barge rising and falling with the tide. To this scows with loaded cars can be brought and thence taken by a locomotive to the dumping ground.

The railway was built under a contract with Mr. C. D. Langhorne, between November, 1891, and April, 1892. All the materials, includ. ing the rails and fastenings, were furnished by the contractor, and the whole work is strictly up to requirement.

The barge, or caisson, was built under a contract with Messrs. H. T. Morrison & Co., of Petersburg, Va., and is also in every respect according to contract.

The locomotive, a second-hand tank engine, weighing, with fuel and water, 36,250 pounds, which had been put in good order before its purchase, was furnished by the Tredegar Company, who also furnished a model iron dumping car.

About twenty dumping cars will be needed to keep two ordinary dredges supplied.

Twelve wing dams have also been built at Wilton, varying in length from 50 to 250 feet. Extensive surveys and tidal observations have been made.

No very heavy freshets have occurred. The following are the most important rises, the heights below being above low tide:

Feet. August 25, 1891

8.3 January 16, 1892

13,5 January 21, 1892

11.6 March 1, 1892

7.8 March 10, 1892

8.7 April 24, 1892

9.4 The completion of the work in Kingsland Reach and the further re. moval of the slide of 1889 in Dutch Gap have been of benefit to navigation. The depths of channels elsewhere have generally been maintained with some improvement due to contraction and dredging. The work done in the rocky bottom for 2 or 3 miles below Richmond has been a further progress toward a wider and deeper channel there, but no improvement in available depth from the sea to the city can be reported from the last year, which was 101 feet at full tide. The surveys of 1890 showed some shoaling from 1880 at Goose Hill Flats and Curles Neck, which reduce the available depth from the sea to Warwick Bar, then reported as 19 feet, to 18.5 feet at full tide.

The present depths of the river at mean low tide, compared with those of 1870 in a channel not less than 30 feet wide are as follows:

1870.

1892.

From the city to Richmond Bar.
Over Richmond Bar and Randolph Flits..
From Randolph Flats over Warwick Bar.
From Warwick Bar to City Point (least in Trents Reach)
From City Point to the sea..

Feet.

7
7
12.4

Feet.

13.8 15 15.4 *15.5 17

14.8

• Trents Reach is now avoided by Dutch Gap Cut-off.

When the proposed improvement is completed an annual expenditure of $20,000 will be necessary for the maintenance of the channel. July 1, 1891, balance unexpended

$142, 957.65 June 30, 1892, amount expended during fiscal year..

98, 902.63 July 1, 1892, balance unexpended

44, 055. 02 July 1, 1892, outstanding liabilities

$2,000,00 July 1, 1892, amount covered by uncompleted contracts. 33, 087.44

35, 087.44 July 1, 1892, balance available

8, 967.58 Amount appropriated by act approved July 13, 1892.

200,000.00 Amount available for fiscal year ending June 30, 1893......

208, 967.58

Amount (estimated) required for completion of existing project ..... 3,536, 070.45 Submitted in compliance with requirements of sections 2 of river and

harbor acts of 1866 and 1867. (See Appendix I 2.)

IMPROVEMENT OF POTOMAC RIVER AND ITS TRIBUTARIES, OF HARBOR

AT BRETON BAY, MARYLAND, AND OF CERTAIN RIVERS ON WESTERN SHORE OF CHESAPEAKE BAY, MARYLAND AND VIRGINIA.

Officers in charge, Lieut. Col. Peter C. Hains, Corps of Engineers, to November 23, 1891; Maj. Lewis C. Overman, Corps of Engineers, November 23 to December 7, 1891; Capt. Thomas Turtle, Corps of Engineers, December 7, 1891, to January 25, 1892, and, Maj. Charles E. L. B. Davis, Corps of Engineers, since January 25, 1892 with Lieut. George A. Zinn, Corps of Engineers, under their immediate orders; division engineer since January 5, 1892, Col. William P. Craighill, Corps of Engineers.

1. Potomac River at Washington, District of Columbia.-Before the commencement of this improvement the channel to Georgetown, D. C., was narrow and crooked, and had not sufficient depth to meet the needs of commerce. Vessels drawing 16 feet frequently grounded at high tide above Long Bridge, and frequent dredging was necessary to maintain even this depth. The channel was of insufficient width, as the appropriations for dredging were too small to provide for more than a narrow cut through the bar. The Washington channel was narrow and shoal and inadequate to the wants of commerce. Extensive mud flats existed along the city front from Observatory Hill to a point opposite the arsenal. Below Long Bridge these flats were separated from the city front by the Washington Channel. The greater portion of these flats was exposed at low tide and covered at high tide by water polluted by the sewage of the city. At the foot of Seventeenth street NW. a large sewer discharged directly upon the flats. These conditions rendered a portion of the city almost uninhabitble.

By act passed August 2, 1882, Congress adopted a project which has for its object the improvement of the navigaion of the river by widening and deepening its channels, the reclamation or filling of the marshes on the city front by depositing on them the materal dredged from the channels, and the establishment of harbor lines beyond which no wharves or obstructions should be built. The project provides in detail for such depth of channels as will accommodate the largest ves. sels that can reach Arsenal Point, with such depth at the wharves as will allow vessels to receive full cargoes without grounding at low water; for filling the flats above Long Bridge to a height of 3 feet above the flood line of 1877, and the middle part of the flats below Long Bridge to the same height, but sloping each way to a height of 6 feet above low tide at the margin of the fill; that in order to purify the water in the Washington Channel, which will be cut off at its upper end from the Virginia or main channel, a tidal reservoir or basin be established above Long Bridge, to be filled with water from the Virginia Channel on the flood tide and discharged into the Washington Channel on the ebb.

The plan also contemplates the rebuilding of Long Bridge, with longer spans and fewer piers, during the progress of the work, and the interception of all sewage now discharged into the Washington Channel and its conveyance to James Creek, but neither the reconstruction of the bridge nor the building of the intercepting sewer were included in the estimate of the cost of the improvement.

The estimated cost of the improvement is $2,716,365.

Appropriations have been made as follows:
Act of-
Angust 2, 1882

$400,000 July 5, 1881.

500,000 August 5, 1886

375, 000 August 11, 1888

300,000 September 19, 1890.

280, 000

1, 855, 000 Twenty thousand dollars of the appropriation of September 19, 1890, was made available for dredging in the Anacostia River, which leaves the aggregate appropriations for the Potomac proper $1,835,000.

Up to the close of the fiscal year 1890 the expenditures aggregated $1,626,821.37, and the following work had been accomplished: The Virginia Channel above Long Bridge had been deepened to 20 feet at low tide for a width of from 400 to 550 feet, a part of which has since filled up and been redredged. The same channel below Long Bridge had been dredged to a depth of 20 feet and a width of about 350 feet. This part of the Virginia Channel has maintained itself to the full depth originally dredged or has deepened. The Washington Channel has been dredged to a depth of 20 feet for a width of 350 feet throughout its entire length, and to a depth of 12 feet from the 20-foot channel nearly to the easterly margin of the fill, from the lower end of the reclaimed area up as far as the Seventh Street Wharf. This channel has for the most part maintained itself, though some filling occurred during the freshet of June, 1889. The juuction of the Virginia and Washington channels had been dreilged to depths of 20 feet, 15 feet, and 12 feet. The greater part of the tidal reservoir had been dredged to a depth of 8 feet. All the material dredged from the river had been deposited on the flats, and of the 12,000,000 cubic yards estimated to be required about 8,566,000 had been deposited. The entire area of the flats, about 621 acres, had been outlined, and practically the entire area to be reclaimed had been raised above overflow at ordinary high tide.

The riprap foundation for the sea wall had been put in place around the entire river front of the reclaimed area and the margin of the tidal reservoir. The construction of the sea wall for the protection of the inargin of the fill trom erosion by waves and the action of the tidal currents had been commenced and 5,100 linear feet of wall constructed. The construction of a dike on the westerly side of the Virginia Channel

above Long Bridge, with a view to reducing the deposit at that locality, was in progress. The outlet gates of the tidal reservoir at the head of the Washington Channel had been completed, with the exception of the coping

The expenditures during the fiscal year ending June 30, 1892, were $171,120.

The construction of the sea wall was continued. The greater part of the wall on the Virginia Channel front above the Long Bridge and about two-thirds of that on the Washington Channel front below the Long Bridge were completed.

A new channel, 1,200 feet wide and 20 feet deep, was dredged by contract through the bar in the Virginia channel above the Long Bridge.

Dredging to 12-foot depth in the Washington channel between the 20-foot channel and the reclaimed area below the Long Bridge was continued until February 1, 1892, when a part of the contractors' plant failed, necessitating a suspension of work. The contractors have thus far failed to resume operations.

The coping of the reservoir outlet has been laid.

Anacostia River.—Under the provisions of the river and harbor act of September 19, 1890, which made $20,000 of the $280,000 appropriated for improving the Potomac River available for the Anacostia River, dredging operations have been in progress, and the channel has been widened and dredged to 20 feet in depth at two localities. The excavated material was deposited on the flats.

Long Bridge.—The northerly end of the Long Bridge across the Washington channel has been reconstructed by the Baltimore and Po tomac Railroad Company on plans approved by the Secretary of War, the work being as yet incomplete, owing to the settlement of the abutments. Reference is made in the report of the officer in local charge to the necessity of rebuilding Long Bridge. In the event of a freshet occurring when the Potomac River is full of ice, great damage is to be expected. The piers of the bridge are of such faulty construction that an ice gorge would be probable, which would cause the water to back up and overflow portions of the city front, and through the sewers above the bridge such portions of the lower parts of the city as may be drained by them. Great damage was done by the freshet of June, 1889, but greater damage may occur from a freshet of lesser magnitude if accompanied by an ice gorge. July 1, 1891, balance unexpended....

$228, 178.63 June 30, 1892, amount expended during fiscal year.

171, 120.00 July 1, 1892, balance unexpended

57, 058. C3 July 1, 1892, ontstanding liabilities.

$703.00 July 1, 1892, amount covered by uncompleted contracts... 41, 183. 00

41, 886.00 July 1, 1892, balance available

15, 172, 63 Amount appropriated by act approved July 13, 1892

200,000.00 Amount available for fiscal year ending June 30, 1893..

215, 172. 63 Amount (estimated) required for completion of existing project ...... 681, 365.00 Submitted in compliance with requirements of sections 2 of river and

harbor acts of 1866 and 1867. (See Appendix J 1.) 2. Potomac River at Mount Vernon, Virginia.Before this improve

ment was commenced the ruling depth over the wide flat between the main channel of the Potomac River and the wharf at Mount Vernou was but 4 feet at low tide. The original project, adopted in 1879, was for a channel 150 feet wide and from 6 to 7 feet deep, with a turning basin at the wharf of 150 feet radius. This project was amended in 1888 so as to provide for a channel 200 feet wide and a turning basin of 200 feet radius. On June 30, 1890, $14,500 had been expended and the channel was about 140 feet wide between the 6-foot curves, and from 60 to 100 feet wide between the 9-foot curves, the depth here varying from 9 to 12 feet. The turning basin was 360 feet wide, but was incomplete. The act of September 19, 1890, provided for the completion of the improvement, and operations have been conducted with this end in view.

The channel has been dredged to a width of 155 feet, with a depth of from 8 to 10 feet, and the turning basin completed, the radius being 180 feet. The officer in charge regards the present dimensions of the channel as sufficient for navigation, and no further appropriations are recommended. July 1, 1891, balance unexpended.

$502.86 June 30, 1892, amount expended during fiscal year.

502. 86 (See Appendix J 2.)

3. Occoquan Creek, Virginia.–Occoquan Creek is a tributary of the Potomac River, which it enters about 25 miles below Washington, D.C. Navigation was obstructed by four bars, which were improved between 1873 and 1880 by the expenditure of four appropriations, aggregating $25,000, giving a navigable depth of about 6 feet to Occoquan, the head of navigation, 4 miles above the mouth. In compliance with the provisions of the river and harbor act of August 11, 1888, a new survey was made in 1889, and the condition of the several bars found as follows:

Lower Mud, about 3.5 miles below Occoquan. This bar is about 4,000 feet long and had a ruling depth of about 3 feet. The former dredged channel had filled in.

Upper Mud, about 2.25 miles below Occoquan. The channel dredged in 1874_75 was found to have maintained its original dimensions, being about 50 feet wide and from 5 to 6 feet deep.

Sand Bar, about one-half mile below Occoquan. The former dredged channel had filled in, the least depth being 4.2 feet.

Occoquan Bar, a short bar opposite Occoquan. The channel dredged here had filled in, and the least depth was 4 feet.

The project for the new improvement comprises the dredging of channels 6 feet deep and from 100 to 150 feet wide through the bars, with the construction of such dikes as may be required to maintain the depth secured by dredging. The first appropriation for the new work was made September 19, 1890. At the close of the fiscal year ending June 30, 1891, $1,605.01 had been expended. The dredging of a channel 6 feet deep and 100 feet wide through the lower bar was then in progress, the condition of the work as regards facility of navigation being, with this exception, substantially the same as at the time of the survey of 1889.

During the fiscal year ending June 30, 1892, the channel through the lower mud has been completed, the depth being 6 feet and the width from 100 to 150 feet, and a channel from 70 to 100 feet wide and 8 feet deep has been dredged through Occoquan Bar. At the last-named bar

« AnteriorContinuar »