This pipe was constructed of sheets of wrought iron riveted together. Each section was fastened with three rows of rivets. At the point of greatest pressure the iron was five-sixteenths of an inch in thickness, but near the ends, upon the sides of the two opposite mountains, it tapered down to one-sixteenth of an inch. In the construction of the pipe there were used 1,150,000 pounds of rolled iron and 1,000,000 rivets, while 52,000 pounds of lead were used in securing the joints of the sections. At each joint the sections were inserted into cast iron sleeves, and it was within these sleeves that the lead was used. The total weight of the sleeves was 442,500 pounds.
The first flow of water through this pipe reached Gold Hill and Virginia City on the evening of August 1, 1873, amid the greatest rejoicings of the people of both towns. Cannons were fired, rockets sent up, and bands of music paraded the streets. Never before in any part of the world had water been conveyed under a pressure so great; and it still remains the greatest. Previous to this, 910 feet was the greatest perpendicular pressure under which water had ever been carried through an iron pipe. This had been accomplished by Mr. Schussler, at Cherokee Flat, California.
Additional Great Pipes.
In 1875 the water company laid alongside the first pipe a second having an inside diameter of ten inches. This pipe is lap-welded, and, there being no friction of rivet heads upon the water, the flow through it is equal to that through the twelve-inch pipe,—2,200,000 gallons every twenty-four hours.
Before 1875 the supply of water was obtained from creeks on the eastern slope of the mountains lying east of Lake Tahoe, but in the year named, the water company pushed their main supply flumes through to Marlette Lake, which lies inside of the Tahoe basin. To do this it was necessary to run a tunnel 3,000 feet in length through the dividing ridge, or rim, of the Tahoe basin. The sheet of water known as Marlette Lake is almost entirely artificial, and owes its existence to a big dam—is in reality a large reservoir. The water covers an area of over 300 acres, and in the middle is about 40 feet deep. The reservoir holds 16,000,000,000 gallons of water.
The second pipe was laid under the supervision of Capt. J. B. Overton, Superintendent of the works of the water company, who also extended the flumes, constructed the tunnel through the mountain ridge, and made all the other improvements. In 1887 a third iron pipe of twelve inches inside diameter was laid across the valley alongside the first two. It was also a welded pipe and delivers much more water than either of the others. The inlet pressure has been raised on all three pipes, and they now deliver a total flow of about 10,000,000 gallons in twenty-four hours. In 1887, also, a branch flume was run to the northward (Marlette Lake lying to the southward) a distance of nine miles, which taps a number of creeks tributary to Lake Tahoe on the east and northeast sides. In the same year a reservoir capable of holding 20,000,000 gallons was constructed on Hobart Creek, on the east side of the dividing ridge. In and near the city are reservoirs holding from 3,000,000 to 10,000,000 gallons, and a number of tanks along the side of Mount Davidson of from 60,000 to 80,000 gallons, capacity. The water is brought a distance of from twenty-five to thirty-seven miles, and the supply (aided by the several storage reservoirs) is ample for all present uses. The total cost of the works of the company has been about $2,500,000. Each of the three pipes has its separate inlet and outlet, from two flumes and into two flumes. Between the outlet and the city the water passes through a large storage reservoir.
The Sutro Tunnel.
While there was a scarcity of water on the surface at Virginia City, there was a superabundance of it, both hot and cold, under-ground in all the mines. Levels were flooded so suddenly that oftentimes the miners narrowly escaped being drowned by the vast subterranean reservoirs that were unexpectedly tapped. Great delays in mining were caused by these floods, and to pump out the water that filled the lower levels cost immense amounts of money. Several tunnels from 1,000 to 5,000 feet in length were run into the mountain, but they were of only temporary utility, as the shafts of the mines were soon below their level. In order to overcome these water troubles, Adolph Sutro early conceived the idea of running an immense drain tunnel under the Comstock Lode from the lowest possible point. A survey was made by Mr. H. Schussler, and work was commenced on the great drain tunnel (since known as the Sutro Tunnel) October 19, 1869. It starts at the edge of the valley of the Carson River, at a point nearly east of Virginia City, and has a length of 20,145 feet—nearly 4 miles. It taps the central parts of the Comstock Lode at a depth of about 1,650 feet. The tunnel is 16 feet wide and 12 feet high. Drain flumes are sunk in the floor and over these are two tracks for horse-cars. It required nearly eight years to construct the tunnel, and the total cost was about $4,500,000. Although the leading mines had their shafts down nearly 3,000 feet before the tunnel was finished, yet it was of great use, as it saved 1,600 feet of pumping.
From the main tunnel branches were run north and south along the east side of the vein for a distance of over two miles, with which the several companies connected by drain drifts from their mines. The flow of water through the tunnel has at times been over 10,000,000 gallons in twenty-four hours. Between the mouth of the tunnel and the Carson River there are 155 feet of fall, but it has never been utilized for driving reduction works. New connections are still being made with the tunnel for drainage. Though it never paid anything near what was anticipated by Mr. Sutro, the tunnel still brings in a snug sum annually. Last year (the fiscal year that ended February 29, 1888) the receipts for royalties amounted to $237,258.33. It costs a considerable amount annually to keep the main tunnel and branches in repair. This great drain at a depth of 1,600 feet below the surface allows of Pelton water wheels being set up in the shafts of the several mines and worked under immense pressure, there being a free discharge from the wheels. At the C and C shaft of the Consolidated California and Virginia, such wheels have been put in every 500 feet from the surface down to the Sutro Tunnel level. The water used on the first wheel on the surface, in the stamp-mill, is caught up, led to the shaft, and used on the second 500 feet below, and so on down to the tunnel level, the power being brought from wheel to wheel to the surface by means of a system of steel wire cables. Thus is transmitted to the surface the power developed by the whole series of wheels.