WHENEVER the administrative heads of great enterprises change, the general public renews for a time it s interest in t h e undertakings intrusted to their care, and when these enterprises have a national importance. the interest is intensified. So it is now with the New York State Barge Canal. At the beginning of the year the incoming State ngineer found eonstruetion work on the barge eanal improvement about one-third completed and contracts in force covering 96 per cent of the total mileage. He also found that, although most of the work was under contmd, many of the contractors had been extremely dilatory, some of them having done very little, notwithstanding the fact that considerable time had elapsed since the award of their contracts. One feature in particular was found to be backward, a feature most essential to the completion of the project, namely, agreements with railway companies whose lines cross the canal, wbereby the necessary bridges may he huilt or changes made. As the general characteristics of the barge canal-its route, dimensions, number and kind of structures, capacity, cost and the like-have often been told before, they nEpd not. now be repeated. Rather it seems pnfpl'able to describe briefly some of the special features. By supplementing these descriptions with views of completed sections of the canal and. othEr views of grea t structures under constrnction, or interesting bits of detaD, a general idea of the undertaking should be (onv?yed. At the opening of navigation last spring several of the new locks were so nearly com pIe ted that they were, put in commission and have been in use during the past season. To maintain navigation on the existing canals, it has been necessary at certain localities to turn traffic into the new channels as soon as tbey were ready. Such a case hac occurred at Oswego, where the canal enters Lake Ontario, and the lock at this junction is, perhaps, the most interesting of any along the whole line, for it is the first siphon lock to be built in this country and also the largest lock to which the siphon principle has ever been applied. All of the 10fks on the canal are filled and emptied through culverts in the side walls, these culverts communicating with the lock chamber by means of lateral openings. termed ports. In all of the locks except, the one at Oswego the flow through the culverts is reglJ.-lated by gates, sliding vertically. In this lock, however, the culvert is curved and forms a neck above the top of the wall. To start the flow in this neck it )s only n,('essary to exhaust the air: to stop the water l1fpds but the readmission of air-a simple applieatiDll of the well-known siphon principle. The interesting part is the device for creating a vacuum. This jq a tank built in the wall and commnnicating by pipes with the upper and lower pools and by an air pipe with the top of the siphon. By filling this tank with water, then closing tho UJlper pipes and opening the lower one. there is )l l'oduced in the tank the effect. of a hody of suspended water tending to escape into the lower ]lool, thus creating the* vacuum necFssary for operation. The opening of a valve draws the air from the siphon to fill this vacuum. and this 8xhaustIon of the air starts the flow of water through the culvert. At a eertain stage the rushing. water carries the remaining air along with itself and reVfrses the action of the tanl", draving back the air and reforming the vacuum, ready for the next operation. The pipe for filling the vacunm tank is 12 inches in diameter, while the outlet measures 20 inches and the air pipe 4 inches. It readily appears, therefore, that all of these valves may be manipulated easily by hand, especially since the regulation of the 4-inch valves is all that· is required, unless the leakage of air necessitates the refilling of the tank. This simplicity and economy of operation and of maintenance and the absence of sleel work under water to deteriorate by rusting, togpther with a less cost. for construction ·at this particular locatIon at· least, are the features that recommended this type of lock. Its USA during the past season has not been disappointing. Two siphon locks aI' now being designed for the recently authorized addition to the barge, canal system-the Cayuga and Seneca canal. The type appeared first in 1896 on a canal in Northern Germany, and since then others have been built at a few places in Gelmany, A movable dam of the bridge type but it has characteristics that doubtless will commend it to an inereasing use. There is anothAr novel type of structure that has recently been built on the canal, having been originated in its deSign, and this also employs thE. siphon principle. It happens that at certain places there are at times considerable quantities of surplus water that must be” disposed of rapidly and yet the .surface must not be lower(,d below a given point. Toco this without the use of regulating gates and the accompanying cost of attendance, it is necessary to have some automatic device. usually a simple spillway with its crest at the required surface elevation. But cases have arisen on the canal at certain points where there was not room to place a spillway of sufficient length to pass the surplus. Hence the new type-designated a “siphon spillway.” It tonsists of a concrete wall in. ,"hieh are left openings in tho form (f siphons. The intake is several feet below th". surface of the body of water that is to he regulated, while the elevation of the outlet is gove.med by the depth of the stream iuto whi('h the 8urplus is spilled, and the bottom of the neck reaches to the elevation at which the water surface must b” maintained. As the neck, is flattened to the form of a broad, low rectangle, with its top at the elevation to which the water may rise before discharge is to begin, the siphon is full when thIs point is reached, the air having been driven out. by the water, and the siphon action becomes automatic. Air vents pierce. the upper side of the wall at low-water surface and thus the stoppage of the flow is also automatic. A short spillway, or drift gap, to carry off foating debris, completes the structure. Two of these have becn built and successfully operat'!l . There an certain stl'Uctllres that have bepn. in course of building on the lower Mohawk River for some. two years, but not. until recently have the outlines of their peculiar features become manifest to others than those immediately concerned. These structures are the locks and dams that are located at. eight places between Schenectady and Little Falls. The peculiar features are embodied in tLo dams, for tltPy are movable dams of the bridge type-the first to be built in this country. In constructing them, i was necessary first to build abutments and piers, the same as for an ordin ary bridg, and also to place a broad concrete sill in the. bed of the river, extending between abutment and pier. After these operations, a bridge SUptWstructure was thrown across. and then the distinguishing features wene added - fabricated steel beams, suspended in pairs, 15 f'eet apart, and reaching from the bridge to t he concrete sill. Upon' these frames were then, placed gates. of heavy steel plate, fitted with rollers for sliding on the uprights. For co n ve n ience in regulating the stream the gates are divided horizontally in two tiers. When they are closed and the structure is in. operation as a dam, the hottoms (f the lower gates will rest on the concrete sill and the tops of the upper series will form the crest of the dam to govern the elevation of the water surface at ordinary stages. 'henever it is desired to permit, the escape of more water than will spill over the crest, the gates are partially raised, one or all, and the wate r passes through the aperture thus provided. In time of 'xtreme flood or during the winter season, both gates and frames may be entirely removed from the stream, leaving an unobstructed channel. To accomplish this the frames are attached to the hridge by a hinge-like joint, so that, they may be swung up under the bridge floor to a horizontal position, .arrying the gates with them. Steam winches, moving on tracks on the bridge floor, wind or unwind chain cables, to perform all of the work of operation. A spectacular feature attending the building of the Barge Canal is a change in the map of the State that. will add to its lakes two bodies of water of conside'able size. These will i mpound a needed water supply, and are known at present on the plans as Delta and Hinckley reservoirs. A profile of the callal across the State sho\s a continuous deseent from Lake Erie to the eonfluenee of Seneca and Oneida rivers, then a rise to the com- (Continuea 0 1 puo' !SC) 278 Typical lock and bridgework. Tipple incline, used with steam Shore delivery attachment to ladder dredge. A cantilever excavator. Bridge conveyor operating a 12 c u bic yard clamshell bucket. Cableway carrying concrete for building lock chamber wall. A tower THE NEW YORK S C AMERICAN hovel to remove excavated material. Guard-gate masonry at head of cut into Mohawk. Dam at Delta-crest 100 feet above foundation. The siphon lock at Oswego. wavator. Crescent dam. (Note rock cut to Hudson in background.) ATE BARGE CANAL Lock, near Fort Edward, approaching completion.
This article was originally published with the title "Progress of New York's State Barge Canal" in Scientific American 105, 13, 277 (September 1911)