The Arizona sentinel. [volume] (Arizona City [Yuma], Yuma County, A.T. [Ariz.]) 1872-1911, 1908-11-11
The YUMA IRRIGATION DAM
(BY DAY ALLEN WILEY IN SCI
ENTIFIC AMERICAN)

the most notable projects con
nected with the reclamation OF
arid lands in the Southwest will
probably be entirely completed.
While the work includes the
storage OF water on a large scale
and its distribution by means OF
irrigating canals, the extraerdl-
nary difficulties encountered by
the engideers in building the
necessary dam and in restraining
the rivers in the vicinity, have
made tho undertaking unique
among the irrigation enterprises.
In a recent issue, feature of
the Yuma project as it is termed
was described in the extensive
levee work required TO confne
the channels of the ella and the
Colorado rivers during high
water, to prevent the reservoirs
and canals from overlooking dur
ing feeds, also to check the
movement of sediment carried IN
such enormous quantities when
the streams are at highwater
mark. The formation Of the en-
bankments by means Of abatis
made from young trees and
brentwood holding the earth en-
bankmentS, also the jetty system
for retarding the flow of the
water, were detailed and illustra-
ted. Another problem necessary
to be solved, however, was how
to create a permanent reservoir
of sufficient size for irrigation
purposes, strong enough to re-
Sist food action, and so construct
ed that it would not be Swallowed
or filed with the sediment. The
great variation of the volume of
water in the Colorado and the
depth of the mud and other de-
tritus on it's bottom above the
rock strata added to the Difficult
tv. A dam across the river was
essential, but the question was
how to build it so that it would
not be washed out, or at least
partly demolished. Could it be
erected on solid foundation, and
could its ends be securely anchor
ed to the formation on either side?
Preliminary surveys for the
general project were made early
in 1904. Several different loca-
tions were also examined to de-
termine the best place for this
structure, and a search was made
for bedrock with diamond-Ore
drilling machinery, at all posi-
BILE dam sites between Yuma and
Picacho. AS a result of these ex-
plorations, the Laguna weir site
was selected as the most desira-
bic one for the construction of a
weir to serve the lardS near
Yuma, high dam and nighttime
canal beng considered impoSsi-
BILE. The type Of weir selected is
one that has been tried during
the last fifty years at numerous
places in India and Egypt under
similar conditions, three dams
having been constructed on the
Nile river within the past fifteen
years, on practically this same
plan, all having served their pur.
pose efficiently and being in OPP
GRAFTON today. This type Of weir
consists of a loose rock structure
with a paving Of stones II feet in
thickness on the downstream
slope, the structure being tied to
gether with three parallel walls
of steel and concrete run longi
tpdinally between the granite
abutments on the two sides o.
the river, the entire structure be
ing further made secure by al
apron of loose rock pitching tel
feet in thickness and fifty feet il
width at the lower toe of the dan
below the sloping pavement
The height Of this weir was t.
be l9 feet above low water, anC
the slope of the downstream sid
IL feet horizontal tie l foot verti
cal, with 50-foot apron below
The design called for the uppe
core wall Of concrete to rest up
on rev Of sheet piling driver
into the bed of the river.
The handling Of the silt Of tn
Colorado is one of the most diff
calf features Of this undertaking