The Arizona sentinel., 1908-12-30
The Yuma Irrigation Project
By Francis L.. Engineer

yineer, U. s. Reclamation Service. mately, about. ....v.... 2O,OOO-acres Lower Yuma Valley, Ari-
 ga, about. ..,...s........ 03,OG0 acres ! A total of. Of............... 90O00 acres The plan provides for futuIe extensions to the mesa ttable) lands south of Yuma and. the canals and headworkS have suffi- cient capacity to serve this area, some 40, 900 acres in extent, which it is proposed to reach with the aid of pumps. Thus total area of about 13O, ,O00 acres is ultimately provided for in the present plans of the Reclamation 1 Service. | The bottom lands at the pres ent time are mainly covered with @ heavy growth of cottonwood, ] willow, mesquite and arrow weed. It's ability to support such vege- tation with the present scant water supply is ample testimony of the inherent richness of the soil.
 THE PROJECT.
 In general terms the Project is I to raise the surface of the river about ten feet above it's normal plane by means of weir some fourteen miles above Yuma; to bring a small canal down on the Arizona side for the irrigation of the lands in the Gila valley; to construct the main canal on the California side through the Yuma Indian reservation from Laguna Dam to the Colorado river, irri- gating on the way the reserva- tion lands; to cross the Cobra do by means of an inverted si phon a few hundred feet down stream from the Southern Pa cific bridge and then carry canals on both sides of the Yuma valley 1 for serving the lands between I Yuma and the Mexican bounda- ry. The main canal, siphon. and east side canal in the valley be- ing of sufficient capacity to serve the future extension to the mt sa land. The lowlands subject to inundation during the annual floods of the river will be pro- tected by staunch levees, and natural sloughs will be amplited and extended artiticially for the removal of surplus water from irrigation.
 LAGUNA DAM.
 The weir, popularly known as Laguna Dam, which forms the main engineering feature of the Project, extends across the Col orado river from the granite hills ] in Arizona to those in California, at point about fourteen miles above Yuma. Borings at the dam site made during the pre- { liminary investigations disclosed no bed rock upon which a high masonry dam might be founded, but they did indicate that D structure of the India-weir type could be readily built and main tained. The type of weir now under construction originated on 1 lirrigation work in India over fifty years ago, and since that time many similar structures i have been erected Tn that coun- try. During the past fifteen years three such weirs have been built across the river Nile in Egypt. Some of these struct- ures are of great length, one across the Some in India being over 12,6OO feet, or more than two and one half times the length of Laguna Dam. They cross rivers similar in character to tbe Colorado. having much more vi oIent floods. One of the rive has a maximum discharge Of about 9O0,O00 second-feet, or seven times the highest recorded l.fiood of the Colorado. When all conditions are considered, the Laguna weir has more ample dI- mensions than the structures above referred to. Laguna Dam is over 47OO feet. or nearly one mile in length. It is composed
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