Water gate

“ At each place where it is designed to discharge water from the Reservoir, a gate house is built far enough into it to reach the greatest depth of water beyond the slope of the embankment. These houses have a wall upon three sides, and the front which faces the centre of the Reservoir has a suitable screen of wood work and wooden gates which regulate the level below the surface for the current of discharge, and the iron pipes leading from these houses have a stop-cock by which the discharge is controlled ”

“ A passage, at the ground level, leads from the platform through the gatehouse tower, across the ditch or canal from the water gate, to the northern curtain, and was defended by gates, portcullis, and drawbridge.
From the gatehouse a dividing wall, 20 feet high and 6 feet thick, extends westward 80 feet to the edge of the inner moat, and thus cuts off the platform and the whole of the southern from the northern curtain. Each face has been embattled, so that should either curtain be taken, the other could still be defended. ”

“ Outside the walls bedraggled houses are built on piles, and here, when the river is low, a hazardous population lives on the needs of the watermen; for at the foot of the rock a thousand junks are moored, wedged in with one another tightly, and men's lives there have all the turbulence of the river. A steep and tortuous stairway leads to the great gate guarded by a temple, and up and down this all day long go the water coolies, with their dripping buckets; and from their splashing the stair and the street that leads from the gate are wet as though after heavy rain. ”

“ The flood-gate, figure 138, is designed to prevent small stock from passing from one field to another through a water-course under a fence where there is low water, while in time of high water the gate will rise sufficiently to allow the floating trash to pass through, but not higher, as it is self-fastening. The invention consists of a gate constructed of perpendicular slats hinged above, and moving. ”

“ Oysters and shell-fish would make it their home; sea-weeds and mosses would cover the bottom, and before long the river would be filled up, and Hell Gate would be closed. This wild turmoil of water just here, this swift-flowing current, keeps the place clear. The tides scour out the river-bed, and help keep it clean for the ships. There are more vessels passing through Hell Gate in a year than at any other place on this continent. ”

“ Ships pass in and out, either at high tide, when the lock or gate can be left open for a time, or, if at other stages of the tide, by means of the lock, which, being made up of two gates at the opposite ends of a long, narrow, canal-like passageway, makes it possible for the ship to pass into the lock, where the water level can be made to coincide with the level of the dock or of the water outside. ”

“ One is to build it and let the water in to the foot of the hill, and then to raise vessels over, the crest of the hill, and down the other side to where the canal again starts, by means of inclined planes, or marine railways.
The other method is by "locks," as they are called. That is, there are built a series of basins with powerful, water-tight gates dividing them. Boys who live along canals well know how locks work.
A boat comes along until it reaches the place where the lock is. It is floated into a basin, or section, of the waterway, and a gate is closed behind it. ”

“ Where a non-navigable river or man-made waterway becomes navigable after a dam or sluice-gate is built across it, the unit that launches the project shall simultaneously have facilities built for the passage of ships or sites reserved for such facilities. ”

“ The rise and fall of the water causes the float to rise and fall accordingly, and the float, in turn, opens and closes the gate, so as to render the escape of the water from under the dam sections proportionate to the height of water in the stream. The purpose of this opening is to control the height of the leaves of the dam, and not the water under the dam. If the dam is intended to be set at half the elevation of the full height of the leaves, this device properly adjusted would only allow enough upward pressure under the leaves to raise them to that height. ”

“ When the gates are nearly afloat, they can be moved with great ease; but at the time of their construction it was considered essential to provide machinery sufficiently powerful to open and close them at low water, when the whole weight of each gate, nearly one hundred tons, rests on the wheels. The crabs and chains were therefore made much stronger, and were more difficult to move, than if they had been merely designed to work the gate under ordinary conditions. ”

“ Instead of the water washing the steps, as it did not many years ago, the gate is sunk down, all awry, in a pit, and the ground is raised high about it. It is a pity that a little public spirit is not forthcoming to shift it again to the water’s edge, its proper position. ”

“ A wretched gate, invariably badly made, probably ruined, admits you to the interior. Some enclose a house with two or three rooms—windowless, white-washed places. Before this is a reservoir of dirty, stagnant water, turned up from a neighbouring well by an apparatus as rude as it is ungainly and laborious: this is used to irrigate the ground, which therefore is alternately mud and dust. Fruit trees or mulberries are planted in rows, and the ground beneath, being ploughed up, is productive of vegetables or corn. ”

“ There are in the first place cross-chains, tightening under pressure, which may be drawn across the bows of a ship that threatens to become unmanageable. Secondly, the lock-gates are doubled at the entrance to all the locks, and at the lower end of the upper lock in each flight. And, thirdly, each flight of locks can be cut off from the lake by an "emergency dam" of peculiar construction. It is essentially a skeleton gate, which ordinarily lies uplifted along the top of the lock-wall, but can be swung across, lowered, and gradually closed against the water by letting down panels. ”

“ The first place that I can well remember was a large pleasant meadow with a pond of clear water in it. Some shady trees leaned over it, and rushes and water-lilies grew at the deep end. Over the hedge on one side we looked into a plowed field, and on the other we looked over a gate at our master's house, which stood by the roadside; ”

“ On the north side the wall rises to include a hill which it there meets with, and on the other three sides the city is surrounded by a ditch, which is filled by the rising tide, when, for a time, the revolting mass of filth that lies in its bed is concealed from view. There are twelve outer gates—four of which are in the partition wall, and two water gates, through which boats pass from east to west across the new city. ”

“ As cellular iron gates are made water-tight, and have to be ballasted with enough water to prevent their flotation, or are provided with air chambers below and are left open to the rising tide on the outer side above, the gates are light in the water and are easily moved; whereas greenheart gates with their fastenings are considerably heavier than water, so that a considerable weight has to be moved when the water is somewhat low in the dock and the gates therefore only partially immersed. ”

“ Though the water-pressure is most uniformly and economically borne by cylindrical gates, they are longer, and encroach more upon the lines of quay with their curved recesses than straighter gates; and, consequently, Gothic-arched gates are often preferred. Straight gates afford the greatest simplicity in construction. ”

“ To stand on the floor of a dry lock and look up at a lock gate eighty feet high, seven feet thick and sixty-five feet wide is an impressive experience, but to see a pair of such gates swing open and shut at the touch of the finger is something to be remembered. The emergency dams look like a steel girder bridge, which, indeed, they are, and provide against accidents by as ingenious a piece of mechanism as the entire system affords. Enormous iron chains with hydraulic springs are stretched across the entrance to the locks to stop any reckless ship which might otherwise strike the gates. ”

“ The upper gates of each lock are double, as a precaution against accident, and have an ingenious arrangement of emergency dams and floating steel caissons, designed to stem the torrent, in case a gate should be smashed, and to allow the gate to be repaired. ”

“ Up from the ledge that forms the bed of the stream, and into the rocky walls, the power-station, about 110 feet long, is built. The up-stream wall of this station is built after the fashion of a dam, and is reënforced by the down-stream wall, and the water flows directly through the power-station by way of the wheels. A construction of this sort is all that could well be attained in the way of economy, there being neither canal nor long penstocks, and only one wall of a power-house apart from the dam. ”

“ Advantage is taken of the natural water power created by the lock to establish by the side of it an accumulator for operating the gates and valves by hydraulic pressure—in the same manner as at the London and Liverpool docks—which works admirably. ”

“ The other means of getting a canal boat over a hill is by means of a lock. When the waterway is stopped in its level progress by reaching a hill, a square place is excavated and lined with rocks so as to form a water-tight basin, the open end being closed by big, wooden gates.
The Bluebird was now approaching one of these locks, where it was to be raised from a low to a higher level. While Hank managed the mules, Neale steered the boat into the stone-lined basin. ”

“ In mountainous country where rivers are comparatively small and their courses are marked by numerous falls and rapids, it is generally necessary to utilize the fall of a stream through some miles of its length in order to get a satisfactory development of power. To reach this result rather long canals, flumes, or pipe lines must be laid to convey the water to the power stations and deliver it at high pressure. ”

“ It is cut up into large squares, and each square is a field that is surrounded by dykes. These dykes are in communication with one another, and all lead to a drain or load, that is to say, to a channel of water of a secondary size, that lies at the level of a few feet above the dykes. To convey the water from the ditches into the drains, windmills are erected, that work machinery which throws the water out of the ditches up hill into the loads. These loads or drains run to the canal at intervals of two miles ”

“ In the Ouse the tide rises and falls, so it is necessary to stop the mouths of the great drains going into it, which is done by a structure of timber or brick-work like the gates of a dock, which close at high tides to keep out the sea-water, and open at low tides to let out the land water. Either from insufficient workmanship or bad locality, or unusual pressure, or from burrowing animals, the land water, or sea water, or both, made a flank movement, and burst up the whole sluice, so that the tide, instead of being confined to the river, obtained free way up the drain also. ”

“ Yes, friend, but the waters never rise beyond a certain height, and they are kept from flooding the city by the great sluice-gate. If that gate were to be opened in the time of inundation, then we should perish, every one. But it never is opened during those months, for if any would leave or enter the city they do so by means of ladders leading from the summit of the wall to floating landing-stages on the moat beneath. ”

“ But in 1880, when the canal had been transferred by the State of Michigan to the United States, as a work of national importance, the Government undertook the construction of a new lock, which was opened in 1881, and which has been described by competent engineers as the finest piece of hydraulic engineering on the American continent. The lock is at the lower end, and is 515 feet long between the gates and 80 feet wide in the chamber, with 17 feet of water on the sills. The lift is 18 feet, more or less, according to the fall in the rapids between Lake Superior and Lake Huron. ”

“ When repairs have to be made stop-gates allow of the water being run off by “off-lets” from a short reach, and afterwards restored with but little interruption of the traffic. These off-lets are pipes placed at the level of the bottom of the canal and provided with valves which can be opened when required. They are generally formed at aqueducts or bridges crossing rivers, where the contents of the canal between the stop-gates can be run off into the stream. ”

“ Here a dam has been constructed, so that the waters above are formed into a lake fifteen miles long by some seven or eight miles wide. From this huge reservoir the water is conducted a distance of one and a half miles through steel tubes to a power-house some thousand feet below{276} in elevation, providing an enormous power for the generation of electricity both for motor and lighting purposes in the city.
The cars run out to the Botanical Gardens, among the most beautiful in the world, and much favoured by climate. ”

“ One cannot tell by looking which is the natural rock and which is the artificial stone wall. There are gates, or rather iron doors, and these are specially defended by being connected with the electric storage batteries. When the current is turned on—as is supposed always to be the case at night, or when the doors are not in actual use—it is death to any one who touches them.'
'All that I know, oh king!' said Fumenta. 'There is also an underground waterfall—an immense body of water ever tumbling through the great caverns.'
'Yes. ”