APPENDIX D.

ANNUAL REPORT ON OMAHA DIVISION, BY MR. SAMUEL H. YONGE, DIVISION ENGINEER.

MISSOURI RIVER COMMISSION,

OFFICE OF DIVISION ENGINEER,
Nebraska City, Nebr., June 30, 1898.

COLONEL: I have the honor to submit a report of operations conducted on works under my charge in improving Missouri River, Omaha division, for the fiscal year ending June 30, 1898.

The operations comprised construction of improvement works in the vicinities of Nebraska City, Nebr., and Fort Leavenworth, Kans., and surveys and examinations at these and other intermediate points where improvements are contemplated.

IMPROVEMENT WORKS IN THE VICINITY OF NEBRASKA CITY, NEBR.

BANK PROTECTION AT NEBRASKA CITY, NEBR.

At the close of the last fiscal year one of the three stone aprons designed to prevent bank caving near the plant furnishing water and electric light for the city was completed. The others were completed July 10. The space between the upper and middle aprons is 150 feet, that between the middle and lowest 100 feet. They are 50 feet long and extend from standard high water to the toe of the subbank.

Their total cost was $513.49, of which $194.85 were expended during the fiscal year of 1897.

The details of cost are exhibited in accompanying statement.

In accordance with your directions, 236 feet of bank adjacent to and below the lowest apron was protected in April, 1898.

The bank consists of fine sand overlying very hard material, probably blue clay, at a depth of 25 to 35 feet.

The protective material is stone riprap, having below water a thickness of 2 to 3 feet, with its onter face on a slope of 1 on 1, and above water, where the bank was graded to a slope of 1 on 14, a thickness of about 8 inches.

One and one-fourth cubic yards of stone per linear foot of bank were expended. The net cost of the work was $714.45.

The details of cost are contained in accompanying statement.

This work has not been exposed to severe stress. It has withstood the April and June rises satisfactorily.

DIKES NEAR NEBRASKA CITY, NEBR.

Specifications and requisitions for bills of lumber, piling, etc., for the construction of two dikes embraced in your project for the improvement of the river at Nebraska City, Nebr., were submitted by me under date of September 1, 1897. By your letter of September 9, 1897, I was notified of changes in the project and authorized to invite proposals for furnishing stone riprap for the work.

The project, as amended, embraced the construction of three dikes, Nos. 3, 4, and 5, two of which, Nos. 3 and 5, have been constructed.

Under date of September 23, 1897, I was notified by you of the approval of project by the Chief of Engineers.

Preparations for proceeding with the work during the fall were made by ordering necessary materials, for which proposals had been taken, and moving to Nebraska City the plant that had been employed during the preceding two months on the improvements in the vicinity of Fort Leavenworth, Kans. ; also the surplus material of that work that was suitable for the Nebraska City dikes.

CONSTRUCTION MATERIAL.

An effort was made to procure native piling for dike work, and proposals to furnish material of that class invited, but none received. An investigation to ascertain the feasibility and cost of procuring that material by day labor was also made, from which it appeared that nearly all of it would have to be brought by rail from a distance, and that its average cost would be about 17 cents per linear foot. The lowest tender to furnish pine piling being 19.3 cents per linear foot, it was decided more advantageous at that figure than the native piling, as the extra cost of handling and driving the latter would have exceeded the difference in price.

With the exception of piles brought from Fort Leavenworth by towboat in October, all pine piling, also lumber and coal, were received by rail and delivered on a short side track on the river bank immediately below the Nebraska City bridge, which is the only point in this vicinity accessible to boats and railroad.

As at the above point, there is only a narrow strip between the river and the side track, and that partly occupied by a wagon road, there is but little space available for storing and sorting material. It was therefore necessary, to avoid congestion, after unloading material from cars, to immediately transfer it to barges and transport it across the river to the boat yard, where it was again unloaded and sorted. This repeated handling of material, entailing great expense, is usually avoided where extensive work is projected by establishing a permanent supply yard with a switch connection to some railway. In this instance such a course was, for obvious reasons, not feasible.

While material was arriving, Dike 3 was under construction, and the carrier barges consequently in demand for that work. They could only be made available for transporting material from the railway to the boat yard by at once discharging material for the dike on its arrival there and working some of the crews overtime, Sundays, and regardless of weather conditions.

Of the pine piling, 425 sticks, or 20,805 linear feet, were purchased under proposals taken on ten days' notice, and received by rail from Mississippi, and 74 sticks, or 2,680 linear feet, transferred from the Fort Leavenworth work.

The piles are of superior quality, having butt diameters of 15 to 20 inches and point diameters of 9 to 12 inches. They arrived between October 25 and November 11. Forty-one cottonwood piles, for mat anchorage, were procured in the vicinity of the work at a cost of 14.8 cents per linear foot.

The pine lumber is of medium quality. It was furnished between November 3 and November 23.

The -inch wire cable for dike stays is made of seven strands, one being central, and each containing seven No. 15 Bessemer steel wires.

Stone riprap, amounting to 1,347.8 cubic yards, was furnished, delivered on the river bank at Jones Point, about 11 miles above the work, at 94 cents per cubic yard. Its delivery was begun in October and completed November 30.

The cost per cubic yard of loading stone on barges at the quarry was 25.1 cents. Brush for fall work was procured partly in the vicinity of the work and partly from a point 5 miles above the dikes. Its average cost was $2.35+ per cord.

During December 520 cords of brush were cut and stacked on a sand bar about 6 miles below Nebraska City for spring work, at a cost of $1.28+ per cord. Early in March this brush was loaded on barges at a cost of 33.6+ cents per cord and towed to the sites of the dikes, where 344 cords were unloaded and stacked on the river bank.

The moving of all brush to the site of the proposed work before beginning operations was a departure from the usual custom of towing it to the work, as required for weaving, and was made necessary on account of there being too few barges available for carrying simultaneously all kinds of material from points of production to those of expenditure.

The unloading of brush on the bank, which involved an additional expense of $94.44, was, for the same reason, also made necessary.

The average cost per cord of brush delivered at the dikes for spring work amounted to $1.98+.

On account of scarcity of timber in this vicinage, a higher value is placed on young trees suitable for screen poles than on the lower reaches of the river. The stumpage paid amounted to 75 cents per cord. The poles were wagoned about 4 miles. Their cost, delivered at the work, amounted in the fall to $2.57+, and in the spring to $3.69 per cord.

The same material as above would have cost on Osage division, prices of 1896, including handling, $10,214.83, or about 25 per cent less. The material still on hand cost $4,234.03.

TOWBOAT SERVICE.

Towing was performed by the towboat John R. Hugo, chartered with crew at $40 per day and $20 per half day.

The additional cost of fuel amounted to $10.48 per day.

The service rendered by the boat was very satisfactory.

When the plant was moved from Leavenworth to Nebraska City, between October 2 and November 4, the river was at a very low stage, and, as this reach has not been worked on by the snag boat for many years, is full of snags. Notwithstanding these difficulties and the prevalence of high winds, on account of which the tows were for several days windbound, the moving was accomplished without serious accident. The aggregate displacement of the tows amounted to 950 tons. The cost of moving, including assembling plant at Leavenworth, was slightly less than 1 cent per ton per mile.

The details of cost are as follows:

Hire of towboat.

4,140 bushels coal.

Total.....

Other services performed by the tow boat consisted of—

Transferring dike piling and lumber from Nebraska City to the boat yard

at a cost of.

Local towing for Dike 3 in the fall of 1897.

Local towing for Dike 5 in the spring of 1898.

Local towing for waterworks protection, spring of 1898.

Total.....

$1, 413.00 355.91

1, 768.91

$127.91

576.46

536.66

132.98

1, 374. 01

The average cost per day of towboat service for the entire period of dike construction was $23.51.

CARE OF PLANT.

When the fleet was moved from Nebraska City, Nebr., to Fort Leavenworth, Kans., in July, 1897, two pieces of plant not required for work at the latter locality were left in charge of two watchmen. Their services until the fleet returned to Nebraska City in October, 1897, and the cost of changing the position of the two pieces on account of shallow water amounted $401.90.

As soon as it was decided to winter the boats at Nebraska City, land for a boat and material yard was rented.

The construction of a set of ways and tracks was begun October 18 and completed November 3. No skilled labor was employed for the work and such of the material from the dismantled Council Bluffs ways as suitable used. As there was no land driver available for placing track posts, these were formed of old timbers set in shallow pits and resting on and spiked to 4 inches by 10 inches by 2 feet pine footings.

Ways construction embraced framing and laying 3,067 feet of tracks and way logs, driving and cutting off under water 54 piles, and placing 305 track posts. The cost of the ways was $1,261.32.

Eight piles were driven along the water front of the boat yard for mooring the plant when out of service; also a line of piling above to deflect floating ice from the ways while storing boats. The cost of these items was $32.66.

A pair of pulling horses was set up at the boat yard to facilitate unloading piling from barges.

The storing of the fleet was begun November 3, between which date and November 13 five of the heaviest pieces were stored. The remaining seven pieces and four large punts were stored on the completion of Dike 3, between November 23 and 27. The cost of storing, including shoring up and leveling the boats on the tracks, amounted to $502.06, or $0.63 per ton of displacement.

The cost at Ewing boat yard was 94 cents per ton in 1894, and 79 cents in 1895.
A watchman's shanty was erected, mostly out of old material, at a cost of $38.77.
During the winter the plant was left in charge of one overseer and two watchmen.
The river opened at Nebraska City February 23.

The ice below Sioux City, Iowa, having passed out, the ways were cleared of gorge ice and launching begun March 5. It was completed March 11, at a cost of $223.13.

In the early spring necesssary repairs, including calking, were made to the boats at a cost of $171.44.

On the completion of Dike 5 in April, three watchmen and an overseer were employed to care for floating plant.

DIKE CONSTRUCTION.

Your project for work at this point, approved by the Chief of Engineers, September 21, 1897, is as follows:

"It is proposed to build three pile dikes about as shown on the accompanying blue print. The trouble at this point is caused by the sharp turn at the lower end of the revetted bend, immediately succeeded by a sharp reverse bend passing to the bridge. "This causes the formation of a middle ground in front of the revetted bend, which at certain stages throws a considerable portion of the flow out of the upper end of the bend over toward the Nebraska City shore, which has cut away. The middle ground at certain stages grows in toward the revetment, making a deep channel with swift current, which threatens the destruction of the revetment.

"By the construction of the proposed dikes it is believed that a channel with easy curves will be maintained, which will be followed by the high and low water flow. It will be noticed that the dikes have curved ends.

"It is hoped to accomplish three purposes by this form:

"First. To throw off the heavy drift, which often destroys pile dikes, either by breaking down the piles, or by unequal distribution, causing scour.

"Second. The easing of the flow around the ends will tend to lessen the depth of the pothole that is always found at the ends of dikes.

"Third. To lessen the eddy below the ends of the dikes and cause the accretion to form nearer to the channel line.

"The interval between the first and second dike is made quite small to take off the head from upper dike, which receives the first and heaviest impact in turning the flow. "The estimated cost of the dikes is $18,000."

According to your oral instructions and plan in outline, the design of the dikes was as follows:

The tops of the dikes to be horizontal and at an elevation of standard high water. With the exception of the outer 100 feet, which were to have two rows of piling, the dikes were to be 3-row work, with the rows of piling and the piling of each row 10 feet from centers. The radius of curved ends to be 340 feet.

Two systems of bracing to be employed:

A top system consisting of the usual wales and transverse braces, and a bottom one of ground braces.

Each dike bent to be reenforced by vertical diagonal stay cables.

The foot mat to extend from 15 feet below the lower rows of piling to 25 and 50 feet above the front row of the straight and curved parts respectively.

Subsequently, you directed a middle system of diagonal bracing to be added. This system consists of timbers 4 inches by 8 inches by 30 feet, placed horizontally with a run of two bents, and bolted to one pile of each row. (Plate V.)

On November 6 your permission was given to omit the ground brace on Dike 3. On the resumption of operations in the spring of 1898, you modified the project by omitting Dike4, and the plan of Dike 5 by omitting one row of piling from the 3-row part, and the bottom and middle bracing systems.

Dike No. 3.-Experience has demonstrated that, ordinarily, a proper complement of carriers for one dike working party is six 100-foot barges and two 64-foot barges. In conducting work with the above complement, material is taken directly from the barges and used as required with a minimum handling, the barges as emptied being replaced by loaded ones. With fewer barges more or less of the material must be unloaded and stored on the bank and subsequently carried out on the dike. This rehandling increases the cost of work to a greater or less extent.

The carriers for "Local works above Kansas City, Mo.," consist of two 100-foot barges and three 64-foot barges.

While this number is sufficient for the necessities of the work, if the piling and lumber are first assembled near it and brush and stone do not have to be towed greater distances than 3 or 4 miles, it is inadequate when the conditions are other than stated, even if great finesse is employed in handling barges.

A full complement of carriers would make more rapid progress with work possible, but as the points where improvements are carried on are widely separated, the expense of moving the additional pieces would be considerable, and in connection with those of building ways of larger storage capacity for wintering the boats, of taking them out of the water in the winter, launching them in the spring, and keeping them in repair, would far more than offset that of extra handling of material. The construction of Dike 3 was begun November 5, and completed November 23. The dike was placed across the then channel of the river. No unusual difficulties

of construction were experienced, although cold, stormy weather made it difficult to hold the working crews so as to complete the dike by the time floating ice appeared in the river. This was accomplished by working Sundays and overtime.

The details of construction are shown on Plate V. Ground braces were placed only in the deep water for the ten inner bents.

The piles of the front row were located by deflection angles, those of the middle and lower rows by measurement from the front row. The average penetration of the piles is 26 feet.

Immediately after its construction a new channel was formed outside of the dike as a result of floating ice collecting and packing above it.

Shortly after completing Dike 3 and laying up the plant the office was closed and office force discharged. The river was closed by ice November 30.

The dike suffered no damage from ice movement in the spring.

Dike No. 5.-By March 5 the ice fields below Omaha had broken and passed Nebraska City.

The period between March 6 and March 15 was occupied in launching the boats, organizing working crews, and towing brush cut during the winter to the dike site. Dike 5 was begun March 16, and, with the exception of the screen, completed April 6.

The progress of work was interrupted by very cold weather and two severe blizzards.

Between April 6 and 8 the screen was placed on the inner 200 feet of dike, and between April 11 and 16, on the adjacent 450 feet. It was omitted, by your direction, from the outer 150 feet. The screen poles are about 10 inches from centers. Their butt diameters range from 5 to 7 inches.

The dike structure proper contains eighty 10-foot bents, the inshore thirty-seven of which are on a line approximately normal to the direction of flow and tangent to the outer part of the dike, consisting of forty-three bents, forming a circular arc, with a radius of 340 feet trailing downstream.

It has a total projection from standard high water contour of about 725 feet. Like Dike 3, it was placed across the main channel of the river.

Coincident with starting the pile driving and foot mat, a scour of 5 or 6 feet at the bottom of the gorged section and a filling of the shallow part of the section beyond occurred.

The anchor piles for the curved part of the dike were located by angles and measurements, and the dike piles by deflection angles measured at the outer end of the straight dike.

The driver was in service eighteen days, on thirteen of which it was employed placing anchor and dike piles. The penetrations of the dike piles range from 233 to 31 feet. The average penetration is 27.8 feet.

Mattress work was proceeded with on twelve days, the average day's work of eight hours amounted to 73.7 linear feet or 5,080 square feet. On account of the unusually wide mat on the curve, a greater number of anchor cables than usual were employed to prevent its being rolled over or turned under by the current.

Mat ballasting was done under careful supervision and, as a precaution against being held up by binding against the dike piles, the mat was cut out around each pile, the loose ends of the brush being fastened by wires to prevent the weaving from unraveling.

In depths greater than 10 feet the attaching of stay cables to the front row piles was done by the driver crew after each pile had been partly driven. For less depths the stays were placed by the bracing crew after the foot mat was sunk. The plan pursued in the latter case was first employed on the Fort Leavenworth dikes in September, 1897, and is thoroughly effective when the inclination of the stay is not much greater than 45° to the horizontal.

The extent and net cost of all parts of the work are exhibited in the following statements: Statement of extent and net cost of dike work.