The record-union. [volume] (Sacramento, Calif.) 1891-1903, 1892-06-24
AN ARTIFICIAL NIAGARA.
New Wonder on the Route to Yosemite
Valley.
The Tuolumne River VIII Glide Over
En Precipice Two Hundred and
Forty Feet High.

.lC1it&s tJhlA41Ae5 NiN N3ilks tteiliA I@ss
Grange to throw the waters Of the Tu-
olumne River into an irrigating canal on
each side.
1t is to lee work greater than any Of
its kind in the world, and is being con-
structed as though not only the reputa-
ton but the life of engineer and builders
was at stake.
A careful survey showed that the most
economical method of diyerIing the
waters of the Tuolumne to reach the rich
sedimentary lands about Turlocl and
Modesto was to build dam 40 feet high
at La Grange, and then conduct the water
by canals, varying in grade according to
character of channel. Through the rocky
bluffs along the river a comparatively
small channel at a grade of twenty-four
feet TO the mile carries large body of
water at race-horse speed. In the sandy
soil OF the lower valley the canal assumes
grand proportions necessary for the slug
gish current occasioned by fall OF one
foot per mile.
1t would seem that 40 feet was an I'M
necessary and dangerous hight for a dam.
but even this rendered il necessary to ex-
cavate channel ninety feet deep for
distance Of half mile on the Turlock
canal.
THE FOUNDATION.
Realizing that this is the most impor-
ant part of a dam, the engineers chose a
site where the bedrock pitched at an
angle OF about thirty degrees against the
current, thus making the most secure
footing possible. They worked through
twenty-six feet of gravel and powders,
and then blasted out an excavation about
three feet deep and ninety-six feet wide
across the channel for a foundation.
TO make this perfectly clean and dry so
as to form the most perfect bond between
the bedrock and concrete, they built Golfer
dams above and below the permanent
dam, and fiumed the river across from the
one to the other. To keep out all water
between the coffer-dams they used a CEN
trlfugal and Blake pump. Not only
was The bottom cleaned and secured but
all the rock used for concrete is thor
oughly washed before going into the
structure, and every rock used in the
wall is similarly cleaned. Three OPEN
lngs, each four feet by five, were lett in
the foundation. These are planned to
carry the natural flow Of the river during
the season Of '92, so that the dam can be
completed without further need of Golfer
dams. When the main dam is finished
these are TO be closed by wooden gates,
and the openings will be filed solid with
concrete. AT present the structure is
sixty-tiye feet high, and the melting
snows are making a stream that pours in
a torrent over the top of the dam with a
roar and spray like that of Niagara.
Bluffs on either side are of solid rock.
and so steep that the crest line of the dam
is only $40 feet long. The dam is built in
the form OF an arch keyed into the solid
mountain at each side. \ great share of
the rocks used in the structure vary in
weight from three to SIX tons and are
quarried on the spot and moved to their
places by complete system of cables and
derricks. The concrete is prepared by a
crusher capable of breaking fifteen tons
OF rock per hour, a cylindrical washer
TOUR feet III diameter and fourteen feet
long, and revolving mixer, into which
six parts of broken rock, two of sand
and one of cement, ARE introduced with an
exact proportion of water and revolved
as butter is churned until the mixture is
perfect. All this machinery is driven by
fifty-horse- power engine. Beside this,
seven donkey engines are stationed at
various points about the bluffs for special
work.
THE CEMENT.
This is of best quality and that which
has been in place three months is so solid
that small fiat stone at the top Of the
dam was broken off in small pieces, but
could not be loosened from the wall.
With miners gads and hydraulic gads
they have tested the strength of the ce-
1hOA1b anu 1OhAlo lIlelG TIC SbIuCblI6 Will
be practically one solid rock. The ma
sonry is technically called 'rubble,' and
stones are of irregular size with all points
carefully broken. To most readers the
abstract figures would convey q less vivid
idea OF the magnitude of the work than
the statement that the cement alone
would load train of cars two miles long
and that the entire structure would re-
qulre train nearly ninety miles long to
carry it away.
THE WATER CUSHION.
This is to be formed by rough dam
few hundred feet below the main struct-
ure, which will keep the water thirty feet
deep in front of the dam, and is called a
cushion because it breaks the fall of the
water from the main dam.
CONTOUR.
On the back side the dam is vertical to
within tour feet OF the top, where it has a
slight curve TO prevent lodging Of drift
wood. On the front the curve is more
gradual and calculated upon hydraulic
principles in such way that the contact
with the structure will be continuous,
and that,the water will leave the dam in
a horizontal course. During the Yosemite
season, when the water is high in the
river, it will be curiosity to see a sheet
OF water $40 feet wide pouring over the
structure as smoothly as sheet of oil.
and descending with q force that will
make whirlpool of the river below and
send up cloud of spray to make the
rainbows linger about the bluffs.
THE GREAT DAM AT vYRMwY. NEAR
LIVERPOOL.
This is the only structure nearly an
preaching the La Grange dam. It was
built on a river of the same name to sup
ply the city of Liverpool with water. Its
crest line is four times the length of orr
American wonder, but it is four feet less
in hight. Again, the Vyrmwy dam was
constructed principally rs storage reser-
VOir with waste WEIR but the La
Grange dam is built to resist heavy cur
rent pouring over the entire structure
That dam was begun in 1882 and COM
pleted in 1883. Ours was begun in 1891
and will be ready for the irrigating sea-
son OF 1898. Three hundred, and as
many more men as can be worked to adj
vantage, viii be employed so soon as the
high water oceasioned by melting SHOWS
subsidies so as to allow the wafer to pass
through the "spill-ways" and work TO
be resumed on the top.
COUNTRY TO BE IRRIGATED.
There are $1,000 acres in the Turlock
district and $4,000 acres in the Modesto
district. These are reported by the en-
gineers who have made the SURVEYS as
Inc best adapted TO irrigation of any tracts
OF their size IN California. The general
character of the soil is sandy loan.
varying from three to ten feet in depth,
underlaid by a bedrock from two to thirty
feet III thickness, bur not so hard but
shat it can be plowed or penetrated by
roots.
Probably very few appreciate the inn
portance of the development likely to re-
suit from the skillful application of this
water. / failed 20 note the number OF
inches of water that the canals are built
10 carry or the supply of the river, but
remember making q mental calculation
IL Il. IL. :. 4 4 l.