Los Angeles herald., 1910-08-14

feet in diameter and twenty feet long,
! and is made of steel plates half an
| inch thick The filtering medium in
each filter contains over thirty tons of
pure SILICA sand brought to this city
| from New Jersey for the purpose
| This sand is different from any usually
seen here. 1t is a bank, not a river
sand, each grain being round in shape,
and, when filtering, the body of the
material becomes compact, the re-
suit being the same as would be
obtained if the water percolated
| through a solid piece of stone four and
| enters the filter from the top, and, per-
colating through the bed of sand, goes
through the lateral pipes into the large
mains. foreign and deleterious matter
remaining on top of the sand.
Cleansing the filters from the impuri-
ties deposited is simplicity itself. By
a system of reversing the valves the
pure filtered water from other units
| goes through the lateral pipes and
screens, breaking up the sand bed and
| forcing all the foreign matter out of
the filter and through trough to the
sewer pipes. The whole operation OF
| washing occupies nine minutes, and
| is the work of one man. This cleansing
! takes place once every twenty-tour
| hours, but once in every forty-elght
| hours would be sufficient.
| All the gates are operated from an
elevated platform, so that the keeper
! has full control of the system and
without any laborious work. .,--
The water supply Of the Southern
California Mountain Water company
is secured from what are known as the
Cottonwood and Otay watersheds, To-
Gated miles back in the country ana in
| the heart of the mountains OF the Guy
amaca range The water is stored IN
| an extensive system of reservoirs, all
of which are of immense capacity. or
the bigger reservoirs any two of them
are amply sufficient to take care of all
| the demands of a city many times the
! present size of San Diego
| In all there are five huge reser-
voirs owned by the Southern Califor-
mia Mountain Water company. Ihree
| of these reservoirs ere completed,
while work is actively progressing on
the fourth. The three reservoirs which
are now finished have capacity OF
! 100000 gallons of water a Day a
supply sufficient for a city OF 5OOO0o
| people. When the fourth reservoir Is
| finished the water will be drawn from
an area of $50 square miles of water
sheds controlled by the company,
varying from 400 feet above sea level
| to more than q mile. A sixth reser-
| voir to be located in Pine valley can
be constructed at any time it is need
ed, thus materially increasing the
available water supply.
Chief among the reservoirs OF the
system is the Morena dam, which is
now under construction and on which
ranid progress is being made. The
work is being done under the super
vision of Chief Engineer NJ NJ.
O'Shaughnessy, one of the foremost
engineers in the west. Mr., O'Shaugh-
IN, =
struction of four immense condults
in the Hawaiian islands, being en-
gagged eight years in the work at
the completion of which he came to
San Diego to take charge of the
Southern California Mountain Water
company's system. He was assistant
engineer eleven years ago in the con-
structiOn of the Spring valley water
system at San Francisco.
The Morena dam is located sixty
miles southeast of the city of san
Diego at an elevation of 5000 feet
above sea level. 1t is in the heart
of the mountains and may be termed
the key to the reservoir system Inc Inc
dam is to be of the rock-ttll type
with a reinforced concrete face. II
viii close a canyon eighty feet wide
aft the bed of the stream. The gran
ite sides rise with a steep slope tc
height of more than 800 feet. The
dam will have a height of loo fee'
and when completed Will hold l0oGo'-
900, 900 gallons of water
BIG CONDUIT BUILT
When the big Morena dam is filed
the water will drop down the Cotton
wood river to the Barrett dam, ten
miles west This reservoir is to be
another important link in the system,
and. like the Morena dam, will have
capacity of IL 600 10000 gallons of
water. This dam will rise 175 feet
above the level of the Cottonwood
river. The reservoir will stretch across
a rugged gorge, the walls Of which rise
abruptly to height OF several hundred
feet In order to secure the strength
that will be required to hold back the
tremendous amount of water it is
necessary to penetrate the walls Of the
gorge a considerable distance to solid
bedrock, in which huge inches are
made to firmly secure the damwork.
After leaving the Barret dam the
water passes through what is known
as the Dulzura conduit, which was
completed early last year. This con-
duit is superior even to the famous
Spring Valley WaterwOrks Of san
Francisco in construction. 1t is thir-
teen miles long and embraces 10000 feet
of tunnel, the greater portion Of which
is through solid granite. The conduit
pierces the mountain range and brings
the water to the western side of the
slope, after which it flows into the
Upper and Lower Otay reservoirs.
The cost of constructing the Dull
zura conduit was great. The big ditch
is six feet wide and seven feet deep,
and in addition TO the tunnel work
necessary in its construction, more than
one and one-half miles of flume line
was built TO be used in carrying the