Arizona republican. [volume] (Phoenix, Ariz.) 1890-1930, 1902-04-27

similar process that may be found eff
| cient in breaking the stones along
regular lines, so that joints to be filled
with mortar may be reasonably thin
and nnlorm.
I MORTAR AND CONCRETE. All
mortar used in the lower 50 feet of the
dam shall consist OF one part of P,rt-
land cement, to two parts of good
sharp sand, and all concrete used in
this portion of the dam shall consist OF
one part cement, two parts sand and
three parts of broken stone graded to
such size as will pass through a screen
with meshes two inches square. The
mortar and concrete used in the up
stream face of the dam for a thickness
of 20 feet shall be of the quality above
specified. In all parts of the dam
which are more than 90 feet from the
upstream face and 80 feet from the
base the mortar shall be one part Port
land cement, three parts sand and four
parts broken stone of size to pass
through a screen with meshes two
inches square. All mortar and con-
crete shall be thoroughly mixed as the
work progresses and used so promptly
that there will be no danger whatever
of inCiPient setting of the cement pre-
Vious to the completion of the masonry
in which it is placed. No cement shall
be used until at least SO days after it's
manufacture. and not until 1t shall
show satisfactory tests according to
the chemical and physical requirements
adopted by the American Society of
Civil Engineers.
The reason for using a larger per-
centage of cement in the base of the
dam is that here Will be the greatest
pressures, and the higher percentage
of cement will give i greater power of
resistance to crushing. The high per-
centage of cement is maintained on the
water face of the dam. all the way to
the top, in order to render it as nearly
!, impervious as possible.
It may be confidently predicted that
masonry dam at the proposed site.
constructed on the above plans and
specifications would be absolutely per-
, manent. safe. solid and secure for all
ages to come as truly as the ever
lasting hills of which it will become
5 an integral part.
! SEDIMENT.
Most of the streams of the southwest
/ carry a considerable quantity of solid
matter which causes annoyance in
canals, and has a tendency to fill any
reservoir constructed on the stream
> This is true of the Rio Grande, Colo
RADIO, Pecos and ella rivers. There is
silt also in the waters of Salt river, as
: shown by it's occurrence in the canals,
but it is not nearly as abundant as in
: the streams above mentioned. The
I basin tributary to the Salt river reser-
: Voir lies in large part in high timbered
5 country and includes the Apache In
: dian reservation. These Indians con-
stitute. probably, the most efficient
p forest patrol in the country, and their
5 reservat ton is almost entirely covered
with forest and grass. The basin OF
s Tonic creek, and few ether tribu-
/ taries. however. are closely pastured
g and deliver some silt during sudden
e Hoods.
Observations CT the amount of sedi-
ment carried give the results found in
= the following table:
PERCENTAGE OF SEDIMENT
: FOUND IN SALT RIVER
! WATER.
h January. 1901. sediment .O26 of / per
e cent: total volume acre-feet, 9.27.
o February. l to 10, .O55 of l per cent;
g total volume acre-feet, 34.42.
= February 16 to %. .O12 of 1 per cent:
I total volume acre-feet. SIS.
0 March, .O099 of l per cent; total vol
e ume acre-feet, 9.53.
. April l to IS. .00021 of / per cent; total
: volume acre-feet, 0.06.
April 10 to May 26, no sediment.
|, May 81 to 81, 1896 of 1 per cent total
e volume acre-feet. 2S.74.
d June, no sediment.
e July, 1924 Of per cent; total volume
d acre-feet, S3.5S.
= August. APPS of 1 per cent; total VOL
: ume acre-feet 1916.
: September, 1923 of 1 per cent; total
n volume acre-feet. %. So.
5 October, .0O54 of per cent; total vol
g ume acre-feet. 5.O4.
e November. O058 of l per cent; total
d volume acre-feet, 0.65.
d December, no sediment.
e Total for the year, 3375S acre-feet.
Y Note. From January l to April 49,
n 1901, observations We're made at Nc
: Dowen station; balance of the year al
e reservoir site.
The above table shows that during
e the period covered by the observations
n the sediment carried was very small
{ in amount, almost negligible; but the
n discharge during the year was far be-
e low the normal, and it is believed that
a the proportion of sediment shown by
d the observations was also below the
e normal. If we take 1000 acre-feet as
= the avera ge inflow of sediment, this
Y will be nearly three times that OBJ
It served during 1901. and yet it would
n require 500 years to fill the reservoir
J. if none were drawn off 1t would prob
o ably be 100 years before the loss OF
: storage capacity would be seriously
e felt. and it would become necessary
5. to resort to methods of clearing it out
e At all times when the river is in flood
y the water in the reservoir will be moro
y or less turbid. The lower the stage OF
If the reservoir and the greater the flood
Il in the river the greater will be the per-
II centage of sediment held in suspension
t, The greatest amount of sediment vii
E. at all times be found in the lower lay
n ers of water and it will therefore con
It tribute to the maintenance f the stor-
5 age capacity to draw all waters from
n the lowest possible point at all times