Year: 1878




A DARING PIECE OF ENGINEERING.


There is not bolder piece of engineer
ing in California than the water works OF
the Spring Valley Mining and Irrigation
Company at Cherokee Flat. When we
state that the supply of water used by the
great hydraulic mine is 36,00O000 gallons
daily, or three times the supply of the city
of San Francisco, while in winter it is in
creased to 7G,000,000 daily, some idea of
the quantity may be gained but when it
is realized that this water is brought from
reservoirs at the line of perpetual snow 63
mites away, through numerous eanal; that
ramify through the Sierra and is at last
placed upon the summit of Table Mountain,
an isolated plateau that stands over 1000
feet above the gorges thai cut it off from
the main range, the magnitude of the
problem solved by the execution of this
new light. 1t was easy enough to collect
this vast quantity Of water and convey 1t
IN bitches along the hill slopes to point
opposite Table Mountain on an equal ele-
vation, but when they talked about carry
ing it in pipe across the deep gorge of the
west fork of Feather river, Intervening
many Of the most eminent engineers of
San Francisco shook their heads and said
it was impossible. 1t was necessary to lay
a pipe 80 inches in diameter in order TO
convey the volume of water required. The
pipe needed to be Il, 900 feet long, with
vertical pressure of S56 feet. Nopipe of
that size had ever been made in the world
to Withstand that pressure. Everybody
sneered at the attempt and predicted that
it would be a failure. One engineer, Her
man Schussler, Chief Engineer of the San
Francisco Water Works, was found who
said the scheme was feasible, and upon his
advice and by his plans the pipe was laid in
1870, proving complete success. But one
pipe in the United States Chat of the water
works of Virginia City, Nevada), has
greater vertical pressure, and no water pipe
in the world as far as known, has SO great
an aggregate pressure as this is required to
withstand. The strain upon the pipe at the
bottom of the siphon is equal to 4O4 pounds
to the square inch. In other words, every
inch in the length of the pipe must with
stand tearing strain of 3S,076 pounds
The thickness of the pipe (Which is of the
best wrought iron), at this point, is three
eights of an inch, double, the thickness
decreasing gradually each way to about
one-sixteenth of an inch at either end.
The pipe crosses the river ona high truss
bridge, with a span of 219 feet. From the
bridge, for distance of about 900 feet on
the south side, the pipe is SO nearly perpen-
dicular that ladders had to be built on the
face of the cliff for the use of the workmen
engaged in laying it. The head, or receiv-
ing end of the pipe, is 1870 feet higher than
the discharge, yet the friction is SO enor-
nous that the water has no great force at
the lower end, and although the orifice is
full, the water is not thrown any distance.
| A box receives it and conducts it to an open
ditch OH the slope of the mountain, whence
it is conducted to the reservoirs above the



| mine.


It is only about mile from the mine to
| the discharge end of the pipe, and the Wis
itor to that section should never fail to &c
| out and see it. The view from that end Of
the mountain is grand and glorious. Range
after range of forest-clad mountains are in
view, while the deep gorge at your feet
| gives you a sense of elevation that you dc
not elsewhere realize. The Sacramento
Valley, too, is spread out before you IN
delightful perspective to the west-the oal
glades about Chico seeming like dense
black forests.


The total length of the bitches forming
the magnificent water-works which w
have been describing is 1s2 miles. One Q
them taps Big Butte creek ;another tn
| west fork of the Feather, and others lea'
minor streams into the main channels, al
concentrating into the reservoir at the up
per end Of the grand syphon which marx
one of the greatest achievements in hycros
tatic science.


Kanaks (natives of the Sandwich Islands
are almost exclusively employed in keepin
the bitches in repair. Although notadap'
ed to the steady, laborious work OF mining
they are excellent for this purpose an
they cannot be excelled in any emergenc
shore diving or swimming is required. ]