Sluice (water)

“ Where skins are used, as in Brazil, they may be dried and beaten over a cloth, placed to receive the fallen particles. Sluice washing is generally carried on during the day only; but when water is abundant and cheap, the work may be continued throughout the whole twenty-four hours. The sluices are cleaned up once a week, or more seldom, according to the rate at which gold and amalgam accumulate. ”

“ Imagine us located a mile above the river on the side of a mountain. We dug at first sluices in the rock to carry off the mud and water, and after it had flowed in these a little way a sluice box was put in to pass it through. These were made on a slope of one in twelve, and the bottom paved with blocks, 3 inches thick, so laid as to make a cavity or pocket at the corner of the blocks. After passing the first sluice box the water and gravel would be run in a bed rock sluice again, and then into another sluice box and so on for a mile, passing through several sluice boxes on the way. ”

“ The stones used are cobbles, six or eight inches through at the greatest diameter, and usually flattish. A good workman will pave eight hundred square feet of sluice-box with them in a day; and after the water and dirt have run over them for an hour, they are fastened very tightly by the sand collected between them. In large sluices, wooden riffle-bars are worn away very rapidly—the expense amounting sometimes, in very large and long sluices, to twenty or thirty dollars a day ”

“ A little muddy water trickles through the line of sluices. One of us goes to the reservoir, a few hundred yards off, and turns on the water. Another goes to the tail of the sluices with the sluice-fork. Then is heard the clicking of the pick and the grating of the shovel against the red dirt; down comes the muddy water over the bank and the day’s work has fairly commenced.
We stand in a row, allowing sufficient room between each for swinging the pick. We are undermining the bank, the water running at our feet and between us and the bottom of the bank. ”

“ If a long trough, divided in the middle by a sluice or partition, have one end filled with water, and the other with quick silver, both fluids will remain quiet so long as they are divided, but when the sluice is drawn up, the heavier fluid will rush along the bottom of the trough, while the lighter, from being displaced, will rise, and flowing in an opposite direction, spread itself at the top. ”

“ When it is desired to remove the sludge deposited in the cone-shaped bottom of the tank, the sluice-valve on the sludge outlet is opened and the sludge is forced up by the head of water, due to the difference in level between the top-water level in the tank and the invert of the sludge-outlet. It has been stated that this method of sludge removal is subject to difficulties, due to the consolidation of the sludge in the cone, to such an extent that it becomes of too thick a consistence to flow up the vertical pipe. ”

“ By the aid of sluice-gates the water could be transferred direct from chamber A. to chamber D. Access was obtained by an opening to the chambers beneath, and the mud was from time to time cleaned out. Curious details of the sluices, &c., have been found; but it is not easy to determine their age, as the aqueducts have undergone so many repeated alterations. ”

“ Ground sluices are natural gullies, answering the purpose of wooden sluices in localities where water is abundant for short periods only, and the construction of permanent sluices would not be judicious. In river mining, the current of a stream is turned aside, and sluices are erected in its bed for washing the dirt there accumulated. ”

“ The slug, called Succinea, is not strictly aquatic, but lives in damp places, and may be seen in full activity far from rivers, in meadows where the grass is wet with rain or dew; but shells of the genera Limnaea, Planorbis, Paludina, Cyclas, and others, requiring to be constantly in the water, are extremely exceptional in the loess, occurring only at the bottom of the deposit where it begins to alternate with ancient river-gravel on which it usually reposes. ”

“ But during the winter, when the stream-banks are embossed in snow, and the streams themselves are chilled nearly to the freezing-point, so that the snow falling into them in stormy weather is not wholly dissolved, but forms a thin, blue sludge, thus rendering the current opaque—then he seeks the deeper portions of the main rivers, where he may dive to clear water beneath the sludge. Or he repairs to some open lake or mill-pond, at the bottom of which he feeds in safety. ”

“ In many lakes, and in the ocean, the quantity of saline matter is so great as to render it unfit for diluent purposes; but, when sea-water freezes, the saline impregnations are deposited; and the ice affords fresh water. In the state in which water is generally employed as a diluent, its impregnations are in small quantity, and not usually sufficient either to dim its transparency, or to give it color, smell, or taste, and consequently to render it unfit for the ordinary purposes of life. ”

“ Waves, whether due to wind or other agency, may cause scour, especially of the banks. Their effect on the bed becomes less as the depth of water increases, but does not cease altogether at a depth of 21 feet, as has been supposed. Salt water possesses a power of causing mud, but not sand, to deposit.
Arts. 2, 3, and 6 of this chapter refer to action on the bed of a stream. Action on the sides will be considered in Art. 7.
Weeds usually grow only in water which has so low a velocity that it carries no silt to speak of, but if any silt is introduced the weeds cause a deposit. ”

“ The saline substances are brought down by rain, which washes the soil and percolates through the rocky ledges, and by the rivers, which are generally estimated to contain from ten to one hundred grains of salt per gallon, [3] and here probably more, owing to the abundance of soda. The evaporation is, of course, nearly pure, containing but very minute traces of salts.
It has been generally stated that the water is fatal to organic life. The fish brought down the rivers perish at once in the concentrated brine ”

“ SEA-SLUDGE, or Salt-clod, is the surface, or that part of a saline marsh, which is deposited by the high tides. It is much richer, and less intermixed with sand, than the land which is more regularly overflowed.
Sea-sludge is an excellent manure; and though it be attainable only in a few situations, yet it deserves to be more generally employed. The best sludge is completely covered with grass: it is cut out of the marshes, to the depth of a spade, and, during the summer, is carted upon the land ”

“ This sewage sludge upon entering salt or brackish water precipitates much more rapidly than in fresh water or upon land, and becomes relatively insoluble, hence the accumulation in harbors, e.g., Boston and New Bedford harbors and the estuaries of the Merrimac, Taunton and other rivers. ”

“ Kinnicutt, Winslow, and Pratt in their book on Sewage Disposal state:
With an average depth of 10 inches per dose of sludge of 87 per cent water content, one square foot of covered (glass) bed should dry to a spadable condition one cubic yard of sludge per year.
500The sludge is run on the bed in small quantities at periods from two weeks to a month apart. In favorable weather Imhoff sludge will dry in two weeks or less to approximately 50 to 60 per cent moisture. It is then suitable for use as a filling material on waste land, for burning, or for further drying by heat. ”

“ High numbers of bacteria in the effluents have often resulted from the discharge of sludge from the sedimentation-basins onto the filters, due to the interference of ice on the action of the floating outlet for the basins, and this, rather than the direct effect of cold, is believed to be the direct cause of the low winter efficiency. ”

“ Of course economy and convenience of working require that the sluice should be near the level of the ground, and as that may be steep or level below the claim, the grade of the sluice must to some extent conform to it. There are thus a multitude of points to be taken into consideration in fixing the grade of a sluice; but a fall of less than eight or more than twenty inches, in a box of twelve feet, would be considered as unsuitable for the board-sluice. ”

“ The hypochlorite was applied at the intake cribs situated a considerable distance off shore. The direction of the wind often necessitated holding the sludge for a considerable length of time but occasionally it was found impossible to await favourable conditions with the result that the wind and wave action carried a portion of the sludge back into the crib and down into the shaft and tunnel.
The temperature of the water at the time of treatment is another factor bearing on the production of tastes and odours. ”

“ For persons who are obliged to prepare temporarily the salt, as travelers passing through the country, the water of the lake, without concentration, may be used for washing out the deliquescent chlorides, sprinkling the heap of salt by a watering-pot at intervals of two or three hours during a single day, and allowing it to drain and dry at night, and be spread to the sun an hour or two the following morning. ”

“ The filtration of water may now be considered. The water of our wells is presented by nature ready filtered to the hand of man, and often exhibits an admirable degree of transparency and purity. It acquires this state by percolating through the mineral strata of the earth, which deprives it of the organic matter it derives from the soil and subsoil, but, at the same time, it dissolves a portion of the saline and earthy media through which it passes, and hence acquires that peculiar ‘hardness’ which is constantly found in spring water. ”

“ Sludge consists of a stratum of detached ice crystals, or of snow, or of the smaller fragments of brash-ice, floating on the surface of the sea.
A stream is an oblong collection of drift or bay-ice, the pieces of which are continuous. It is called a sea-stream when it is exposed on one side to the ocean, and affords shelter from the sea to whatever is within it. ”

“ Muddy waters result principally from the action of rains upon the surface of ground capable of being washed, and the turbidities of the stream at any point below will occur at the times when the muddy waters reach it in the natural course of flow, and will disappear again when the muddy waters present in the stream system at the end of the rain have run out, and have been replaced with clear water from underground sources, or from clearer surface sources. ”

“ During the high-level stage the water was fresh, but gradually, as the climate became drier, evaporation was greater than intake, the outlet was abandoned, and the mineral matter (mostly chloride of magnesia and common table salt) carried by the streams in solution into the shrinking lake steadily accumulated until the high degree of salinity of the present time has been reached. ”

“ That in time of flood a large proportion, both of the suspended and dissolved filth, is conveyed down to the intakes, and in ordinary weather considerable portion of soluble organic matter makes its way to the pumping works, and is still present in the water distributed to the consumers. ”

“ The surface-water, on the contrary, is very variable in its composition, sometimes at certain places almost drinkable, and in summer often strongly heated. The remarkable circumstance takes place here that the surface water in consequence of its limited salinity freezes to ice if it be exposed to the temperature which prevails in the salt stratum of water next the bottom, and that it forms a deadly poison for many of the decapoda, worms, mussels, crustacea and asterids which crawl in myriads among the beds of clay or sand at the bottom. ”

“ Spread over a large area of land, well cropped, evaporation is very active—especially during the summer months, when the flow of water in the brook that takes the effluent is as a rule at its lowest; and, in addition to this, the growing plants further abstract a considerable amount of the liquid that finds its way into the soil, so that the quantity of the effluent may not be more than from 30 [Pg 68] to 50 per cent. ”

“ When barriers of lime, ashes, etc., are ineffective, traps consisting of pieces of board sacking and similar materials placed about the field prove inviting to the slugs. They collect under these and by going over the field in the early morning they may be put into a salt-water solution or otherwise destroyed. Arsenical sprays applied with an underspray nozzle to the lower surface of the leaves will help control the slugs. ”

“ While the stream is often turbid with surface waste washed into it by rains, the spring remains clear; its water has been filtered during its slow movement through many small underground passages and the pores of rocks. Commonly the spring differs from the stream in that it carries a far larger load of dissolved rock. Chemical analysis proves that streams contain various minerals in solution, but these are usually in quantities so small that they are not perceptible to the taste or feel. ”

“ The effluent which is turbid, putrescible and rich in organic matter cannot be discharged into streams with safety without further treatment, unless the volume of water is sufficient to complete the purification by dilution. ”

“ After the height of the flood the stream clears itself by the flowing away of the turbid water much more rapidly than the water clears itself by sedimentation in the reservoir. That is to say, if at the time of maximum turbidity we take a certain quantity of water from the stream and put it aside to settle, at no time will the improvement by settling equal the improvement which has taken place in the stream from natural causes. ”