The San Francisco call. [volume] (San Francisco [Calif.]) 1895-1913, 1899-02-24
GIANT FILTER
IN COURSE OF
CONSTRUCTION
Will Provide Pure and
Clear Water.
FEATURE THAT STANDS UNIQUE
PART OF THE SPRING VALLEYS
SYSTEM.
Will Cost Nearly Half Million Dol
lars and Be Ready for Use by
September Next.
FEATURE THAT STANDS UNIQUE
PART OF THE SPRING VALLEYS
SYSTEM.

Tn q. great work that 1t has just be-
gun in the neighborhood of Sunoi, Ala
media County the Spring Valley water
Works is making record that is
unique in connection with furnishing
large cities with adequate and pure
supplies of water. 1t is constructing an
auxiliary to it's water system for San
Francisco that will comprise as one OF
its features a large filter basin with
superficial area of not less than 2oO,OoO
square feet By means Of this all the
water obtained from watershed drain
ing about 500 square miles Will De
filtered through a natural bed of gravel
before it enters upon its travels through
the conduits of the company TO It's
thousands of patrons.
In the year 1887 the Spring valley
Water Works began operations on the
eastern side of the bay for the purpose
of conducting the waters of Alameda
Creek across the bay Of San Francisco
and adding them to it's already vast
resources on the peninsula of San Fran
cisco.
Since that year more than $1,000, O00,-
900 gallons have been drawn from Ala
media Creek and furnished to the city
of San Francisco, thus augmenting in
most material manner the water sup
ply on this side of the bay.
| To show the necessity of the addition
| of this magnificent auxiliary water sup
ply for this city at and since the time
| of its acquisition, it is sufficient to
state that the reservoirs of the Spring
| Valley Water Works on the peninsula
! now contain in the neighborhood of H.,
! 900, 600, 900 gallons, which would never
| have been possible had not the COM
| pany had the aforementioned waters
| of Alameda Creek from which to draw
! Always exercising the utmost care
! and vigilance as to the quality of the
water it undertakes to supply to its
| patrons, the company concluded TO I'M
prove the manner in Which the water
| was drawn from Alameda Creek. Dur
| ing transforms and freshets the water
| of the creek becomes very riley or
muddy, necessitating the shutting off
! of this supply. If this were not done
| there would have been danger of filling
! the submarine pipes extending across
! the bay of San Francisco with mud.
! But aside from this inconvenience the
! company naturally did not want to
| carry muddy water to San Francisco.
In order to remedy this defect lands
! and water rights were secured along
! Alameda Creek at an elevation of about
! 200 feet above high-water mark, near
/ SQnOl Station here COnCEeIS QdIu
was constructed. About three quarters
of a mile above this Sunol dam the
| two main creeks of this vast watershed
come together. The stream coming
from the south is Calaveras Creek,
which controls about two hundred
square miles of watershed, while La
guna Creek coming from the north,
controls more than three hundred
square miles of watershed, making a
| total area drained by these two water
courses of more than five hundred
square miles and all controlled by the
Sunol dam.
Between the forks of these two
streams magnificent gravel bed from
an eighth to a fifth of a mile in width
and fully mile in length is situated.
In this gravel bed the company pro-
poses TO excavate a large filtering
basin, containing in the neighborhood
of five acres, and which will be about
two hundred feet in width and about
a thousand feet in length 1t will be
necessary to eXcavate the surface
gravel from ten to twelve feet to get
down to the water level A further ex-
cavation will then be made of from ten
to twelve feet below the water level.
At the northern end of the huge filter
ing basin a masonry gateway will be
built from which 36-inch cast
iron pipes will carry the water under
meath Laguna Creek into masonry
lined channel $500 feet in length on the
north bank of Alameda Creek to the
north end of the Sunol dam. This dam
will be so broadened and raised that
the aqueduct described will lead
through it's hollow top to the south end
of the Sunol dam, whence it will con-
duct the water into a masonry-lined
tunnel 1000 feet in length. From the
outlet of the tunnel it will enter an
aqueduct 1000 feet long, masonry lined
| q nd NIT q fnyN n -
against floods. From the lower or
western end of this aqueduct fiume
five feet wide, three feet deep and four