Page images
PDF
EPUB

vessel answers very well for harbor work, serving practically only for sounding in still water and for housing the field party. On the open lake a survey vessel fitted for sounding and sweeping should have a length of 100 to 120 feet, a beam of 18 to 24 feet, with a draft of 9 to 12 feet, ample power, a speed not greater than 12 miles, living accommodations for a total of 20 to 30 men, and, above all, ample deck space, unhampered by superstructure other than pilot house, smokestack and engine room hatch and skylight. Freeboard should be the least compatible with safety. Such a vessel, fitted with capstans, winches, and hoists, all mechanically operated, is capable of doing work of sounding and sweeping with ease and economy, and should cost not to exceed $50,000. Three of them would amply replace the five above described now belonging to the Survey.

The season for survey work on the Great Lakes at the utmost extends from May 15 to November 15, a period of six months. This is a short time and should be used to the highest possible advantage, with ample funds and an efficient equipment.

The present approved general project for the operations of the Lake Survey contemplates the completion of all surveys and other operations needed to modernize and improve and complete the series of charts and will require eleven seasons of work with the existing equipment employed to its full capacity. Such employment will require an annual appropriation of $125,000.

I therefore recommend the appropriation of this amount, as follows:

For survey of Northern and Northwestern Lakes, including all necessary expenses for preparing, correcting, extending, printing, and issuing charts and bulletins, and of investigating lake levels with a view to their regulation, to be immediately available and to remain available until expended, $125,000.

Dates and amounts of appropriations for surveys of Northern and Northwestern

[blocks in formation]

Printing and issue of charts for use of navigators and electrotyping copperplates

[blocks in formation]

Surveys, including investigations of lake levels, correcting, printing, and issuing

[blocks in formation]

Oct. 18. 1908. Feb. 20.

Mar. 9.

Apr. 2.

May 6.

Deposits to credit of appropriation:

Overpayment on voucher 68, August, 1907__

By Col. Chas. E. L. B. Davis, Corps of
Engineers, for sweeping float_.

By Capt. G. R. Lukesh, Corps of Engineers,
printing maps for Mississippi River Com-
mission

By Capt. G. R. Lukesh, as above_

Overpayment on voucher 19, October, 1907_
By Chief of Engineers, for 3,500 pounds
chart paper

June 10.
June 18. Allotted from act approved March 4, 1907.
Allotted from act approved May 27, 1908_

By Capt. G. R. Lukesh, as above..

June 30. Amount withdrawn during fiscal year.
Amount expended during fiscal year----

Balance unexpended

Outstanding liabilities

Balance available.

$75,000

75,000

125, 000

925,000

$73, 628. 33

[blocks in formation]

"Amount expended during fiscal year includes $7,103.60 deposited to credit of appropriation as above itemized, which had been previously included in expenditures of present or past years. Deducting this amount, the net total expended and withdrawn is $69,603.64.

HHH 2.

PRESERVATION OF NIAGARA FALLS.

At the beginning of the fiscal year, under an allotment of $5,000 from the appropriation of the act of June 29, 1906, field operations had been in progress since May 20, 1907.

The field party under Junior Engineer Sherman Moore continued work until December 14, 1907, and then returned to Detroit for the purpose of reducing the results and preparing a report.

The programme of operations outlined in the project dated April 30, 1907, and approved by the Chief of Engineers May 8, 1907, was completed with the close of the field season of 1907. It included such slope, discharge, and current observations as would help to determine the effect of existing and proposed diversions of water for power purposes, at and near Niagara Falls, upon the level of Lake Erie, the navigable capacity of the Niagara River, and upon the scenic grandeur of Niagara Falls, so far as the last depends upon height of crest and volume of flow, these being measurable elements.

The following extract from the report of Principal Assistant Engineer Francis C. Shenehon details the field operations and office work involved:

At the beginning of the fiscal year the season's work, begun at Niagara Falls in the latter part of May under Junior Engineer Sherman Moore, was well advanced. Self-registering water gauges had been set at Black Rock, Chippawa, Grass Island, Suspension Bridge, and in the Whirlpool, and some staff gauges at other places; soundings in the approach to the rapids had been completed and some work done on a contour survey of the rapids.

Early in July, 1907, seven triangulation stations of the New York State survey of 1890 were read into the triangulation net of the Lake Survey to serve as further references for studies on the recession of the crest lines of the Falls.

On July 9, a sixth self-registering gauge was set at Wing Dam, in the upper reach of the American channel, and arrangements were begun for measuring the flow in that channel. A section where the flow was most uniform for a length of 100 feet with fairly smooth water was selected, and ranges to mark the terminals of the 100-foot base were set up. Standards of timber were erected on Goat Island and the main shore as abutments, and a line was carried across the channel by means of a kite, and a cable of signal cord stretched across. In attempting to taut this cable up to sound from it, it was overstrained and broken. Later in the season a new cable of 2-inch Swedish iron, resting on 16-foot towers, was stretched across the channel. A carrier was built to ride on this cable, and by means of a tripping device floats could be sent out and dropped into the stream above the 100-foot base, with such spacing laterally as the observer chose.

Two series of floats were dispatched from this starting cable: First, a series with varying stem lengths, which served to give the depths, needed to get the cross-sectional area; second, a series to determine velocities at all points. Operating in this way, twelve distinct measurements of the volume of flow through this channel were made. It appeared, on the reduction of these observations, that the flow at the time of the measurements was about 4.8 per cent of the full river volume.

On July 22, the three current meters intended for the extensive measure ments in hand were taken to Cayuga Creek and, during the following five days, were rated on a still-water base.

The measurement of the flow in the canal of the Niagara Falls Hydraulic Power and Manufacturing Company was then taken up. The best section available in the lower canal was at Main street, and, operating from the bridge there, twenty measurements were made of the volume of flow. This work was done with exceeding care in all details, and occupied the party from July 29 to August 24.

Meanwhile a second section, whose measurements would serve as a check on the results obtained on the Main street section, was established toward the upper end of the canal at the New York Central Railroad crossing. As the bridge here cuts the canal diagonally, it was necessary, in order to get a section normal to the axis of the canal, to erect a cableway and build a carriage from which the meters were operated. In measuring the velocities here, as at Main street, three different current meters were used, and generally two meters simultaneously, following the two-meter method used by me in work on the Niagara and St. Lawrence rivers, as described in the reports of 1900 and 1903.

Coefficient work alone was done and no discharge measurements, as such, were taken. The final reduction in both of these sections was to establish such coefficients that, when the velocity is measured in a single controlling point in the section, and a gauge reading accompanies this measurement, the volume of flow is indicated. The test of the accuracy of each section was that simultaneous measurements at Main street and at the railroad crossing should show the same volume of flow. It is very satisfactory to state that, despite extremely broken flow, due to dredging in progress, the movement of a tug and dump scows, and the presence of falsework partially blocking the canal where bridges were under reconstruction, the check in the volume of flow by the two independent sections is 1.7 per cent.

The maximum flow through this canal, as measured, was 3,080 cubic feet per second, which is less than half the water permissible in the allowance granted under the Burton Act. In December twelve additional measurements of the flow were made at Main street.

On September 6 work was begun on the measurements of flow in the canal, or forebay, of the Niagara Falls Power Company. The first of the two sections measured is about 200 feet below the head of the canal. Two cables were stretched across the canal, elevated at the sides by wooden trestles. The observing carriage, carrying one man and two current meters, traveled on this cableway. A box gauge, with bottle-and-staff float, was placed against the west wall close to the section. The cross-sectional area was determined by very careful soundings, measurements of the side slopes, and water-surface readings. The profile of the bottom was checked by a series of instrumental level readings, on a long rod, with cutwater edge, which rested on the bottom, and a similar series was read on the water surface.

The two-meter system of stream measurement was used on this canal, as on the Hydraulic Canal. While measurements were in progress on the cableway, a third meter was operated at the head of the canal, at a fixed percentage depth, and suspended from a fixed point on the pulp-wood conveyor viaduct. The object of this third meter was to establish a single station, such that velocities measured there in connection wtih a water-surface reading at the cableway, or on the section gauge, would permit the volume of flow to be easily computed by means of reduction coefficients. All the current-meter work was done with great care. Up to October 7, fifteen measurements of the volume of flow were made.

While this work was in progress the flow was measured passing through the canal of the International Paper Company, which branches from the Power Company's canal above the hydraulic section occupied by the cableway. The flow through the hydraulic section, with the addition of the flow in this branch canal, constitutes the diversion of this company.

As the amount of water used by the Power Company varies somewhat with the time of day or night, on October 2 and 3 a continuous measurement was made for twenty-four hours. The Sunday flow was, later in the season, also determined.

The current meters were re-rated on a still-water base in Cayuga Creek after October 7.

The party then went to Buffalo and made forty different measurements of the flow of the Niagara River from the International Bridge. The hydraulic section of the river here is the same as used in 1897 to 1900, and fully discussed by me in the report of 1900. In the measurements of the past year no coefficient work was done and no soundings made, the cross-sectional area and the reduction factors being taken as established in 1898-99. These measurements were made between October 21 and November 4, and utilized all meters.

The object of these measurements was to test the level of Lake Erie by deriving its elevation from the discharge formula,

Elevation of lake = Function of Discharge.

So far as these results go they show no lowering of Lake Erie to have resulted from the increase in the diversions since 1898-99.

At the same time sixteen measurements of the volume of flow in the Erie Canal were made, showing a mean flow of 768 cubic feet per second.

On November 6 the current meters were rated again at Prospect Reservoir in Buffalo on the same rating base used by me in 1898-1900.

The party then returned to Niagara Falls and made fifteen additional discharge measurements on the original hydraulic section in the canal of the Niagara Falls Power Company. A second hydraulic section was then laid out about 75 feet below the first section and twenty discharge measurements were made between November 20 and December 5. The results obtained by this new independent hydraulic section check the results on section No. 1 within less than 2 per cent.

During the time of these measurements on sections 1 and 2 the diversion of the Power Company shows a mean of 8,335 cubic feet per second, which is less than the authorized limit of 8,600 cubic feet. However, at times the diversion reaches 9,200 cubic feet, which exceeds the limit by 7 per cent.

In the latter part of November, when work was in progress on the measurements in the Power Canal, a box gauge was set close to the crest of the American Fall at Prospect Point, and a series of floats was thrown from the Goat Island Bridge to determine the depth on the brink of the fall at thirty-five different places along the crest line.

On December 11 and 12 check levels were run to test the elevations of all gauge zeros, and the party left for headquarters at Detroit on December 13. During the winter the work was reduced and the great amount of data collected was assembled, analyzed, and prepared for publication. A report of al! operations and results was prepared.

It is not too much to say that at the present time the intangible problem presented has been rendered tangible, and that decisions on the points arising out of water diversions are on a footing of simple demonstrated fact.

Junior Engineer Sherman Moore, who has had immediate charge of the surveys and reductions, is entitled to warm commendation. The work has been delicate, difficult, dangerous even, but it has been handled safely and adequately.

The allotment of $5,000 made April 27, 1907, having become exhausted February 1, 1908, before the reductions were completed, the work was continued with Lake Survey funds. The amount thus expended up to May 31, 1908, was $2,008.73, and this is to be refunded to the Survey from the appropriation under the Burton Act.

The work accomplished having proven satisfactory, and valuable, it appeared desirable to extend the observations through another season, with a view of getting additional light on the question of the effect of the diversions on Lake Erie and of getting still further data on the equivalent lake and river heights as shown by the water gauges. The evidence on the effect of diversions on Lake Erie was slightly contradictory, and it was proposed to make sixty additional measurements of the volume of the flow of the Niagara River, operating from the International Bridge, as before, as a further test.

Under date of May 18, 1908, an allotment of $3,000 was made from the appropriation under the Burton Act, and on May 24, Recorder Fred Lockwood was sent to Niagara Falls to install the water gauges preliminary to the work projected. On June 12, Junior Engineer Sherman Moore, with the remainder of his party, went to Niagara Falls.

On June 14, the two power companies on the American side shut down for a few hours. The effects of this cessation of diversion was observed by a series of gauge readings and current-meter measurements. A storm on Lake Erie, resulting in a decided rise at Buffalo, interfered with the conclusiveness of the test. For that portion of the time when the weather was quiescent the effect at different points in

« PreviousContinue »