Imperial Valley press., 1914-09-19

spaced in the High Line canal at every
six miles for two reasons: First, to
avoid as much sitting of the canal as
possible, as pointed out by Mr.. Pedley,
and. second, to facilitate the delivery
Of water.
Due cognizance was taken of the fact
that the secondary mains from which
the lateral canals take out, would slit
up to some extent, but the benefits to
the system as a whole with the side
main deliveries far exceeds any expense
of their maintenance. The system was
therefore deliberately designed along
these lines without any reference
whatever to the existing systems in the
Valley
The spacing of the checks in the
main itself accomplished the first
result desired, that is, the elimina-
ton of a great deal of sitting, which
would have taken place had they been
spaced every half mile, except in the
upper reaches of the canal. Here the
heavy sands have been deposited and
have blocked the entrance to the canal,
causing great expense for cleaning.
This is condition which is develop
irg all over the valley, even in such
canals as the Brawley and Central
mains, where the original grades have
been maintained for eleven years
without sitting. During the present
year great difficulty is being expert
enced in keeping them clean. The
great increase in the quantity of wa
ter discharged through the Hanlon
gates results in increased velocities
and silt-carrying power each year,
tring;ng from from the Colorado river
heavier sands. Unless this condition
is remedied at or near Hanlon Head
ing within the next two years it will
be almost impossible to maintain the
head reaches of any canal in the val
ley.
The second reason for installing
checks every six miles and the use
of the side mains was to facilitate
the delivery of water. Mr.. Pedley
evidently has not had sufficient ex-
rerience in the maintenance and op-
Grafton Of a system of this size to
teach him the value Of what we might
term the unit delivery system" from
main canals.
The system of the California De-
yelopment Company was fortunately
partially designed on this theory, and
curing the whole period of time in
which it has been operated by the
receiver the recognized superiority of
this system of deliveries has led him
to develop it to its fullest extent.
The knowledge gained from twelve
years of practical experience in the
delivery of water from the main ca
nals Of the California Development
Company system led to the adoption
Of this method for the High Line ca
nal. The High Line canal is some
fifty miles in length, serving over
100000 acres of land. This is an
irrigation system in itself larger than
any other system in the state out
side Of Imperial Valley. The canal
is held jointly by three separate
companies, Water Company No. 7,
Water Company No. and Water
Company No. 3, and each company
has the right to expect absolute equity
in service from the canal Had de-
liveries from the main been made
every one-half mile proper service to
the lower reaches Of the canal would
have been absolutely impossible, and
L large part Of the lands depending
upon the High Line canal would be in
il constant state of flood or drought.
The more deliveries depending upon
the water carried in the main, the
greater the discrepancy in measuring,
en- account Of the personal equation
which is bound to enter when de-
livery is made, no matter how care
fully the measurement is taken. The
quantity of seepage and
evaporation varies in every hour Of
the day, every day Of the month and
in every month Of the year, especial
~ where all of one side of a canal
is in desert state This is also