The San Francisco call. [volume] (San Francisco [Calif.]) 1895-1913, 1897-08-29
The Ctys New Storage Reservoir Near Eucalyptus Hill.

| ing OF the mountain produced CLAW
seams. They absorb water, but transmit
little or none, and they act as an incase-
ment for holding the water in the jointed
and porous strata. Joints and cracks ex-
tend from one clay seam to another; they
are irregular and are not connected Most
OF them are closed, but frequently they
are found open, and form channels for the
flow of water.
"ln the construction of tunnel, when
one OF these Clay seams is penetrated
large and sometimes a violent flow of
water occurs, lasting for a few days until
the water in the immediate vicinity is dis
charged and the limiting effect of retard-
alton by friction asserts itself.
"Meteorlc water, such as rains, SHOWS,
dews and fogs is the origin of ali springs
and streams existing i'll the Santa Ynez
range. The flow from the springs and
streams varies with the quantity of local
rainfall. The average annual rainfall for
SAINTS Barbara is 1915 inches, but it is
fully 20 inches on the mountains.
zone inch Of rainfall covering one mile
square would amount to II, 424 900 gallons,
and an annual fall of 20 inches on each
square mile of these mountains would be
34S, 480, 600 gallons. 1t is difficult to OBJ
tain any definite basis or data upon which
to predicate the amount of rainfall alb
sorbed by the mountains. The strata of
these noun aims being so highly inclined,
broken, scanned, jointed and rugged, it is
fair to assume that 80 per cent of the an
nual rainfall or 104. 544, 900 gallons is alb
sorbed by each square mile of mountain
surface.
"The evaporation of the streams of these
mountains is very great during July, Au-
gust and September. A stream flowing
$4,000 gallons in the morning has been
known TO diminish to II, 900 gallons at 2
p NJ. of the same day.
Mature after cycles OF years and infin-
lite labor, has created water reservoirs OF
immense capacity in the interior OF this
range. The water is pure and whole
some, as 1t Is tree from organic con tamin-
alton and remote from agencies of pollu-
ton.
1.-THE tunnel acts on the principal of
natural canyon, but III las several advant-
ages over the canyon. No water is lost by
evaporation, and it is kept free from con-
terminating substances
I'll tunnel be constructed so as to drain
mile square of territory and the for
nation absorb six inches depth of
water annually over its entire area and
the how to tunnel or stream is extended
over 800 days by the limiting action of
friction, then daily flow of 800, 600 GAL
Ions could be expected, and no more.
NV ater,s as it has been found by noun
tain tunneling at San ia Barbara may be b.
tanned In many places in California. Near
cakianu tney nave 1oonshly run tunnels
With tue stratltlcatlon instead of crosscut-
ting it. and they have penetrated the
mountain too near its summit.
ITO obtain the best results in the con.
struction OF tunnel the following rules
should be observed: Enter the mountain
as far below the summit as possible, for
the greater the depth the greater the
hydrostatlc pressure and consequently the
greater the percolation. Cut the strata at
right angles with the strike in order TO
penetrate the greatest number OF clay
seams and impervious strata and to tap
more of the porous water bearing strata
Seek the strata in which sulphureted
water is found, as such flows are perma-
nent. Penetrate to the anticline, that