The nearer hills having thus been drained, tunnels were run into such of those further away as were of sufficient altitude to permit of streams from them being brought to the two towns.[towns.] These tunnels were run for no other purpose than to find water. A hill was examined with a view to its water-producing capacity. It was found that those which rose up in a single sharp or rounded peak were not rich in water. The best water-producers were hills on the tops of which there were large areas of flat ground. That portion of a range of mountains which contained on the summit a large shallow basin surrounded by clusters of hills or peaks was found to yield largely and for a long time, when tapped by a tunnel run under the basin or sink at the depth of three or four hundred feet.
Dams were constructed across the outlets of these basins to hold back the water from the melting snow, in order that it might filter down through the earth to the tunnels. At the mouths of the tunnels heavy bulkheads of timbers and plank were constructed, to keep back and dam up the water where it could be kept cool and pure. Where deep shafts stood near the line of these tunnels, ditches were dug to them along the sides of the hills, and the water formed by the melting of the snow in the spring was let into them. All manner of devices, in short, were resorted to for the purpose of keeping in and upon the hills all of the moisture from snow or rains that fell upon them. Yet one after another these hills failed. When once the tops had been thoroughly drained it appeared to require all of the water that fell on them in any shape during winter to reach down into and moisten them to the level of the tunnels. Finally, there were in all many miles of these horizontal wells. All the hills from which water could be brought, for miles away to the northward and southward of Virginia and Gold Hill, were tapped, thousands on thousands of dollars being expended in this work. When a reservoir of water was first tapped in a new hill there would be poured out a great flood for a few days; this would then fall to a moderate stream and so remain for a month or two, when it would begin to dwindle away. The water from the many tunnels was collected by means of small wooden flumes or troughs, winding about the curves of the hills for miles, and in summer, when most wanted, the sickly streams from the more distant tunnels were lost by leakage and evaporation before having finished half their course to the towns.
Virginia City and Gold Hill were frequently placed upon a short allowance of water, and it was seen that a great water famine must soon prevail in both towns, in case the tunnels that had been run into the mountains were depended upon for a supply. The Virginia and Gold Hill Water Company then determined to bring a supply of pure water from the streams and lakes of the Sierra Nevada Mountains—from the regions of eternal snow.
The distance from Virginia City to the first available streams in the Sierras was about twenty-five miles; but between the Virginia range of mountains and the Sierras, lay the deep depression known as Washoe Valley,—in one part of which is situated Washoe Lake. The problem to be solved in bringing water from the Sierras to Virginia City was how to convey it across this deep valley.
Mr. H. Schussler, the engineer under whose supervision the Spring Valley Water Works, of San Francisco, were constructed, was sent for, and crossing the Sierras he made an examination of the route over which it was proposed to bring the water. He acknowledged that the undertaking was one of great difficulty. To convey the water across the deep depression formed by Washoe Valley would demand the performing of a feat in hydraulic engineering never before attempted in any part of the world. This was to carry the water through an iron pipe under a perpendicular pressure of 1,720 feet. This feat, however, Mr. Schussler said could be performed, and he was ready to undertake it at once.
Surveys were made, in the spring of 1872, and orders given for the manufacture of the pipe. To make the pipe was the work of nearly a year. The manufacturers were furnished with a diagram of the line on which it was to be laid and each section was made to fit a certain spot. When the route lay round a point of rocks the pipe was made of the required curve, and other curved sections were required when the line crossed deep and narrow ravines.
The first section of pipe was laid, June 11th, 1873, and the last on the 25th, of July the same year. The whole length of the pipe is seven miles and one hundred and thirty-four feet. Its interior diameter is twelve inches, and it is capable of delivering 2,200,000 gallons of water per twenty-four hours. It lies across Washoe Valley, in the form of an inverted siphon. The end at which the water is received rests upon a spur from the main Sierras, at an elevation of 1885 feet above Washoe Valley. The outlet is on the crest of the Virginia range of mountains, on the eastern slope of which are situated the towns of Virginia and Gold Hill. The perpendicular elevation of the inlet above the outlet is 465 feet. Thus is brought to bear a great pressure which forces the water rapidly through the pipe.
The water is brought to the inlet through a large wooden flume, and at the outlet is delivered into a similar flume, twelve miles in length, which conveys it to Virginia City. The pipe is of wrought iron, and is fastened by three rows of ⅝ inch rivets. At the lowest point in the ground crossed, the perpendicular pressure is 1,720 feet, equal to 800 pounds to the square inch. Here the iron is 5/16 of an inch in thickness, but as the ground rises to the east and west, and the pressure is reduced, the thickness of the iron decreases through ¼, 3/16, down to 1/16.
In its course, the pipe crosses thirteen deep gulches, making necessary that number of undulations, as it is throughout its length laid at the depth of 2½ feet below the surface of the earth. Besides these, there are a great number of lateral curves round hills and points of rocks. There was just one place and none other for each section of pipe as received from the manufactory. At each point where there is a depression in the pipe there is a blow-off cock, for the removal of any sediment that may collect, and on the top of each ridge is an air-cock, for blowing off the air when the water was first let in, and at other times when the pipe is being filled. The pipe contains no less than 1,150,000 pounds of rolled iron; is held together by 1,000,000 rivets, and there were used in securing the joints 52,000 pounds of lead, which was melted and poured in from a portable furnace that moved along the line as the work of laying the pipe progressed. Before being put down, each section of pipe was boiled in a bath of asphaltum and coal-tar, at a temperature of 380 degrees. At the first filling of the pipe a stream of water, about the thickness of a common lead-pencil, escaped through the lead packing of a joint, at a point where the pressure was greatest. This struck against the face of a rock, and, rebounding, played upon the upper side of the pipe. The water brought with it from the rock a small quantity of sand or grit, perhaps, but at all events it soon bored a hole through the top of the pipe, and from this hole, which shortly became two or three inches in diameter, a jet of water ascended to the height of two hundred feet or more, spreading out in the shape of a fan toward the top.
When this break occurred, a signal smoke was made in the valley, and the lookout at the inlet of the pipe on the mountain spur shut off the water. Over each joint in the pipe was placed a cast-iron sleeve or band, weighing 300 pounds, and within this sleeve was poured the molten lead which served as packing. In all there were used 1,475 or 442,500 pounds of these sleeves, and but three out of the whole number proved faulty, and failed to sustain the strain brought upon them, and of 12,640 sheets of iron used in the pipe, but one bad one was found. As it would have been a great task to test each section of the pipe by hydraulic pressure at the manufactory, the engineer proposed to bring the whole under the required strain at once, after they were put down. He began the pressure with a perpendicular height of 1,250 feet in the column of water; increased it to 1,550, to 1,700, and finally to 1,850, being 130 feet more than the pipe would be required to sustain when in actual use.