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Culvert to be 4 feet by 4 feet 10 inches in completed section; to be capped with stone not less than 2 feet thick, well bonded into lock-walls. In excavating through lock-wall for culvert great care must be used and sides of excavation left smooth. If deemed necessary the excavation for culvert must be of sufficient width so that the side walls of culvert can be built up in a good and substantial manner.

REMOVABLE DAM.

Dam will be built as shown on drawing. All timber to be of good, sound white pine free from imperfections. Framing to be done in the best manner. Bottom timbers of dam to be well bolted to lock floor. All removable parts to be neatly dressed. Recesses to receive ends of dam to be cut in the masonry as shown.

GATES AND SILL.

Gate to be built after the general plan of those now in use. All timber of the best white oak. All iron work to be of the best quality. Dimensions to conform to drawings to be furnished..

Miter-sill to be oak. Miter wall to be capped with 12 inches by 12 inches timber bolted through to the solid rock. A course of 3-inch planking then laid on upon which the miter-sill will rest. Miter-sill to be well bolted to the underlying timbers.

EXCAVATION.

The material to be excavated consists of earth and bowlders in unknown proportions. The cross-section of excavation to conform to the section of the improved canal. The work must be so done as to give a clear depth of 16 feet of water.

PIER REVETMENT.

Pier revetment will be of the same design and built in the same manner as the revetment of the improved canal.

PUMP AND PUMPING MACHINERY.

Pump to be a centrifugal pump of approved make, capable of pumping 10,000 gallons a minute to a height of 30 feet; to be provided with suitable inlet and discharge pipes and the necessary valves and fittings.

Engine and boiler to be of sufficient power to obtain the required duty from the pump without crowding

Engine house for inclosing engine boiler and pump will be of brick, with iron roof, to be built in accordance with plans to be furnished.

KEEL BLOCK TIMBERS AND BILGE BLOCK WAYS.

Keel block timbers will be of three pieces of 12 inches by 12 inches pine timber placed side by side through the center of the lock and bolted to the lock floor.

Bilge block ways will be of 10 inches by 12 inches, timber laid about 12 feet apart and well bolted to lock floor; with channel to receive bilge block steps in either side, and provided with a suitable racking well spiked on.

SHORE RESTS.

Rests or steps, to receive the ends of shores used in supporting vessels, will be cut in the lock walls; to be placed as directed, and will be in number about three to each 12 linear feet of wall.

DRAINAGE.

The contractor will be required to build the necessary coffer-dams to keep the works free from water, and to remove the same upon completion of the work.

FINALLY.

The contractor will be obliged to furnish all of the workmanship and materials required for the completion of the work, and must make his work conform to the drawings which will be furnished him, which drawings shall form part part of these specifications, and to the directions of the engineer officer in charge.

ESTIMATE of cost OF TRANSFORMING UPPER CHAMBER OF OLD LOCKS INTO A DRY

DOCK.

Removing miter and head walls and stone cutting and setting stone:

Removing 155 cubic yards stone-work, at $2

400 square feet stone cutting, at $1

80 cubic yards stone reset, at $10

Removable dam:

4,625 feet, B. M., of timber and plank, at $40. 350 pounds of iron (bolts and spikes), at 6 cents. Stone cutting (recesses at ends of dam)

$310

400

800

1,510

185

21

44

250

[blocks in formation]

Removing miter and head walls, stone cutting about gate recesses and reset

[blocks in formation]

300

325

375

2,500

12,000

840

96

564

1,500

300

5,000

$1,510

250

10,000

5,000

24,000

2,500

12,000

1,500

300

5,000

62, 060

6, 206

68, 266

LL 5.

IMPROVEMENT OF HARBOR AT CHEBOYGAN, MICHIGAN.

The project for the improvement of this harbor was adopted in 1871, the object being to afford a channel from the original mouth of the river, 200 feet wide and not less than 14 feet in depth.

This project was modified in August, 1882, to provide for the deepening of the basin opposite the steamboat landing, and the entire channel to the 15-foot curve in the Straits of Mackinac, thus making the depth 15 feet for the full width of 200 feet.

At the date of the Annual Report for the fiscal year ending June 30, 1883, the basin had been deepened to 15 feet, and this depth with a width of 200 feet carried, down stream to the slip between McArthur, Smith & Co.'s and the railroad dock, thence by a channel of the same depth and 110 feet wide for a length of 1,600 feet, and finally a cut 90 feet wide on the axis or range line out to the 15 foot curve in the Straits of Mackinac.

No appropriation was made for the fiscal year 1883-'84, and no work was done.

By act of Congress approved July 5, 1884, the sum of $5,000 was appropriated for continuing the work. Meanwhile no complaints of the insufficiency of the channel have been received, and it has been deemed prudent to reserve this appropriation until a sufficient sum is added to it to make it worth while for contractors to undertake further work, and thus through competition give to the Government the advantage of lower prices, or some pressing necessity arises in the absence of such additional appropriation as will justify the payment of the higher rates for dredging, which the small amount of the funds at present available would compel contractors to charge. Consequently the appropriation of July 5, 1884, still remains.

I think that the estimate heretofore submitted of $50,000 for the completion of the project is entirely too small, and after consideration name $100,000 as the probable cost.

The original estimate for this work was

Amount thus far appropriated..

Received from sale of fuel...

Revised estimate of amount required to complete the project.......

Total....

Difference.

$395,000

118,000

3

100,000

218, 003

176, 997

The foregoing estimate indicating that the work may be finished for so much less than the original estimate is based upon the possibility that the long pier provided for and intended to protect the channel may be omitted. Should this not prove to be the case the original estimate will be found not to have been too great.

The reasons for undertaking this improvement have been frequently stated in Annual Reports, and it is deemed unnecessary to repeat them, but merely to say that the extension of railroads to and beyond Cheboygan has increased the importance of the point even more rapidly than was anticipated, and the amount necessary to push the project to completion is submitted, and an appropriation of $50,000 for the fiscal year 1886-87 is recommended.

The work is located in the Michigan collection district, Michigan. The nearest port of entry is Grand Haven, Mich., and the nearest light-house is the beacon on the pier-head marking the outer end of the channel.

Money statement.

Amount appropriated by act approved July 5, 1884
July 1, 1885, amount available

Amount (estimated) required for completion of existing project........

Amount that can be profitably expended in fiscal year ending June 30, 1887 Submitted in compliance with requirements of section 2 of river and harbor acts of 1866 and 1867.

$5,000 00 5, 000 00

100, 000 00

50,000 00

L L 6.

IMPROVEMENT OF HARBOR AT THUNDER BAY, MICHIGAN.

The project for the improvement of this harbor was adopted in 1876, the object being to obtain an entrance channel, from the bay into the river, of navigable width, and of not less than 13 feet in depth. The project was subsequently modified with a view to obtaining a depth of 14 feet. This had been practically accomplished at the date of the last Annual Report, when it was stated that the improvement is of such a character that it will require attention from time to time, and as the nature and extent of this could not be foretold, it was recommended that a sufficient appropriation be made to render available the sum of $10,000.

This recommendation I now respectfully renew. The sum required is $5,465.96.

At the beginning of the fiscal year the sum of $4,541.96 was available.

No demand has arisen for extensive work, and only $7 have been expended, leaving $4,534.96 still available to meet any sudden emergency. The commerce directly benefited by this work is that to and from Thunder Bay River, at the mouth of which is situated the important and rapidly growing town of Alpena.

The improvement made gives great satisfaction.

It is located in the collection district of Huron, Mich. The nearest port of entry is Port Huron, Mich., and the nearest light-house is at the work.

Money statement.

July 1, 1884, amount available.

July 1, 1885, amount expended during fiscal year, exclusive of outstanding liabilities July 1, 1884.....

July 1, 1885, amount available..

Amount (estimated) required for maintenance of existing project..
Amount that can be profitably expended in fiscal year ending June 30, 1887
Submitted in compliance with requirements of section 2 of river and

bor acts of 1866 and 1867.

134 ENG

$4,541 96

7.00

4,534 96

10, 000 00

10, 000 00

LL 7.

IMPROVEMENT OF HARBOR AT AU SABLE, MICHIGAN.

The present project for the improvement of the harbor was adopted in 1866, and modified in 1879, the object being to obtain a channel of not less than 10 feet in depth for a width of 100 feet from the Lake to the State Road Bridge at Au Sable.

I have always had serious doubts as to whether an improvement of any substantial value is practicable at this harbor at reasonable cost. During the past year I have examined the history of the work, and submit herewith in an appendix marked "A" my notes upon the subject.

My study of the matter has forced upon me the conclusion that it is not possible to make any permanent improvement of the harbor at any cost at all commensurate with the advantages to be gained.

A balance of $4,900.55 remaining from appropriations heretofore made has been available during the entire fiscal year, and I have stood ready to propose its expenditure in any alleviative measures, should complaint reach me concerning the condition of the harbor, but none has been made. The present condition of the work is as follows: Beginning at the State Road Bridge and going downward for a distance of about 3,200 feet, the main channel is separated by the north revetment from a network of smaller channels fed by the river and used to store logs and float them, as required, to the mills below.

The entrance to these log channels just below the bridge supplies them with a quantity of water greater than that which the chutes below can discharge without considerably increased velocity of flow.

The revetment is therefore exposed to a pressure from the rear tending to force it into the channel at the same time that its hold on the bottom is weakened by increased scour.

It is constructed of piles backed by slabs and edgings from the mills. The upper part, for about 1,800 feet, is what is known as the Backus Revetment, constructed originally by private parties and subsequently turned over to the Government.

It consists of a row of piles, backed by edgings, and is supported throughout the greater part of its length by a narrow bank of sand, which separates it from the log channels.

Prior to May, 1883, a portion of it just below the bridge was forced away by the pressure and scour of the water in the log channels, and the remainder was subsequently strengthened by an additional row of piles along its front.

This row shows a gap where two or three piles have been washed out, but has served its purpose up to the present time.

The complete repair of this revetment, including the construction of a suitable entrance chute, was estimated in the Annual Report for 1882 to cost $4,500.

Below the Backus Revetment and connecting with it, is a pile and edging wall built under Major Harwood's direction in 1880-'81. This consists of two rows of piles 7 feet apart, the inner row capped and waled, and the space between the rows filled with slabs and edgings. There is no sand-bank in rear. It extends about 1,550 feet downstream, and is pierced by four chutes affording connection between the log booms and the main channel.

It is in good condition along the greater part of its extent with the following exceptions: The filling has sunk below the level of the cap

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