Los Angeles herald., 1891-12-30
CITY WATER.
A VOluminOus Report from
the Committee.
City Engineer Dockweiler's
Plans.
Two Systems Outlined and Their
Cost Estimated.
An Exhaustive Study of the Question
The Sources of suppIy-AIl
the Features Con-
s,dered.


The special committee of the counci
which has been at work formulating
plan for city system of water works
yesterday completed its labors. City
Engineer Dockweiler, acting in conjunc
tion with the committee, has prepared
two plans for municipal water works
system. The report is as follows:
No new surveys were made for this
work, but all the data were obtained
from the records OF the engineers office
and where these data lack perfection
for this particular purpose they were
amended by estimation. The report can
therefore, not go into detail sufficient
for the construction OF such important
and costly work, but will only deal with
the problem in general, leaving the nu-
merous details to be perfected whenever
the work is ordered done. Nevertheless
the matter presented herein will suffice
to give you a clear idea of the problem
before us. -
THE SOURCE OF SUPPLY.
As a matter OF course, we look first to
the source of our supply, and we find
that the Los Angeles river carries wat er
enough to supply all future wants of the
city. The nature of the river, however,
is such that we will have to draw our
supply from different parts of the
stream, i. e.: from points at different
elevations, for the river is fed by
springs and other subterraneous sources
as it descends. We find that we may
depend upon q permanent supply of
about 30 cubic feet per second near the
head OF the river, at point where the
present supply ditch OF the city receives
its water, and again for a further 80
cubic feet about at a point where the
Los Angeles City Water company takes
its supply from the river.
This will supply the city with 80 cubic
feet of water per second, or about with
3S,580,000 gallons per day. Allowing
200 gallons per head per day, this will
suffice for population of about 1913, 900
persons.
AT both sites the water is best collect
ed by subterraneous pipe lines, laid with
open joints, along and below the river
bed, deep enough to be secure against
disturbances caused by freshets. While
SUCH an arrangement of infiltration will
not furnish means to eliminate to any
considerable degree the organic impuri-
ties contained in the water, it will never
theless act as a strainer and prevent the
debris and silt carried along by the river
from entering the pipe lines and reser-
voirs.
THE PLAN OF FILTRATION.
To effectively filter the water of the
river and remove from it practically all
Objectionable matter, special arrange
ments will have to be provided.
The water from the first source may be
conducted by gravity into reservoir No.
at the north city limits, the water
level of which has an elevation of 435
feet above sea, being about 155 feet
above Broadway at the city hall.
The second supply may be brought by
gravity close to the city, in the vicinity
OF the reservoir of the Los Angeles City
Water company, which has an elevation
of 375 feet above sea, or 80 feet above
Bro adway at the city hall.
The sources of supply, together with
the decidedly undulating character of
the ground upon which Los Angeles is
built-the elevations varying from 200
to over 800 feet sbove sea-not only
limit but also complicate the solution OF
our problem.
THE EXTENT OF TIE SYSTEM.
1t can at once be seen that only that
part of the city can be supplied with
water from the foregoing sources di-
rectly by gravity which lies below the
contour having an elevation of 400 feet
above sea, which part comprises but lit
tie more than one-half the area of the
town; for the other half, the water has
to be pumped to reservoirs OF higher ele-
vations. from which the supply will then
be by gravity.
Assuming the population of the city
at 100000, it is estimated that the
higher part of the town will contain be-
tween fifty and sixty thousand inhabit-
ants. Allowing them about 200 gallons
of water per day, it will be seen that it
requires the pumping of 10000, 900 gal
Ions per day.
The sources of supply and the location
of the two main reservoirs, however, as
we'll as the varying elevations of the city,
make it necessary for economic reasons to
divide the city into three different dis
tricts, each one being supplied by an in
dependent system.
The territory covered by the first sys-
tenn or district No. l, shown on the ac-
companying map by yellow color, en-
bodies all that part Of the city which
lies below Seventh street. Its area is
about 5400 acres, and its estimated pop
ulation $4,000. At 200 gallons per head
per day, it will require s, 100000 gallons
to supply it's wants, or about 13 cubic
feet per second. Itis supplied directly
from reservoir No. 7, which will give
difference of level between the reservoir
and the district varying from $50 to 250
feet, or an available pressure in the
mains varying from 30 to 80 pounds per
square inch. 1t may be observed that
this pressure will suffice for fire pur-
poses in this district, and that the latter
can therefore be well taken care of by
direct gravity from reservoir No. z.
The second district comprises all that
country lying above the contour having
an elevation OF $50 feet above sea, and
Boyle Heights to Louisiana avenue. 1t
is colored blue on the map. Its area
equals nearly 5000 acres, or about half
of that of the city. Its final population
is assumed at 58, 600 persons. Allowing