Imperial Valley press., 1920-08-28

the length of these dams and in the
length of the levees necessary, must
have a proportionate bearing on the
total cost. Oh. the different projects. 1t I
is more reasonable to assume that
there will be little on no difference in
the cost of the structures and machin-
cry.
Incidentally, referring again to
Table I,awhy should the horse power
to be derived from the project covered
bv Application 1924 fall so far short
of that to be developed by the other
two projects, the flow of water ard
the vertical drop being the same in all
three cases.
To further analyze the estimated
cost of these projects as shown by
these applications, Mr.. Casey assumes
he can build dam in this soil to the
height he names and maintain slopes
of one to one. This he will find i'm
possible I doubt if there exists, in
this valley today, fill under q wagon
road which has slopes sleeper than
one and one-half to one, and any ir-
rigator knows that levee, to hold
back even three feet of water pressure
must havo a slope Of at least two to
one.
The Saiz Levee, which this year had
against it maximum head Of about
IL feet, has Landslide slopes of four to
one, and even then, the toe of this
slope sloughed off so barly that it be-
came necessary to rip-rap it with
wall df sand bags.
My judgment of the slopes required
for dams of the heights named in these
applications would be three to one for
the waterside slope and four to one
for the downstream slope. Ny reason
for discussing at such length this
question Of slopes is because the yard
age to be removed in the construction
Of these dams varies directly as the
slopes given them.
With slopes such as | have suggest
ed above, the yardage to be moved in
each of these contemplated dams would
be as follows:
Appln. 1913, 4,45O cubic yards.
Appln. 1914, 134. 400 cubic yards.
Appln. 1924, 40,95O cubic yards.
Assuming this earth can be placed
for 60 cents a cubic yard, and this
price would not cover any unusual con-
ditions, we find the approximate cost
Of the earthwork involved in each dam
to be as follows:
Appln. 1913, $32,G700O.
Appln. 1914, $50 $4,000.
Appln. 1924, $24, $1,000.
The applications are silent as to
whether it is the intention to put q
core we'll in each dam. | should con-
slider it highly advisable, but, if done,
then the expense of such wall must be
added to our estimate. To this also
must be added the cost of the six or
eight miles of connecting levees men
toned above.
The next item of expense to be con-
sdered is the structure necessary to
pass the water from the upper to the
lower level and to house the machinery
force into electrical energy. In any
estimate of this item of cost it must
be borne in mind that any structure
placed in either the Alamo or New
River, channel, must have sufficient
capacity to.pass all the water which
may, at any time, come down such
channel.
am leaving out of the discussion
the consideration of cloudbursts,. al
though they constitute very real and
often present danger. Many of US
remember the cloudburst Of 1910,
which put out of business every county
bridge on New River from Dixieland
to the Salton Sea. The Alamo also has
been called upon many times to take
care of cloudbursts which broke along
the eastern rim of the valley.
But aside from these, let US consider
how much water we NAV reasonably
expect to have turned down on US
through the ordinary operations Of the
irrigation District in handling their
large canals. The Alamo carries to
Sharp's Heading during the summer
morths, for the use Of the Central and
the Westside Main Canals, approXi-
mately 1900 second feet. Should any
serious trouble occur. or even threaten,
the district would throw open the
Alamo watergate and "shoot" all this
water down the Alamo channel.
Similarly, in the case Of the New
River, We're any trouble to occur in the
Central Main Canal, the "134" waste
cate would be opened and 1900 second
feet would be dropped into New River,
while trouble on the Wpstsde Main
Canal would bring the Wistaria waste
into action and the flow of the New
River would thereby be increased some
1900 second feet. These are occur
rences which, in the past, have hap
pened MANY times and must be anti
cipated in the future and provided for
in the design of any structure TO be
placed in these channels.
| cannot, without actual surveys and
plans before me, give you even an ap-
proXimate estimate of the cost of the
structures necessary to drop these vol
umes of water the heights called for
in hese applications, but it might af-
ford us basis for a rough appriXa-
mate when we consider that the orig
inal Rositas Wastegate, which drops
the same volume of water a height of
27 feet, cost, under the scale Of nrices
twisting in 1910, the sum of S55,250
This price / should expect to see
doubled We're the same structure un-
dertaken today.
] have not gone into the cost of the
for these power houses. but
I believe we have gone'far enough to
zee that. aside from the necessary ont