THE YUMA RECLAMATION PR()JE("r. 887 



several feet below the lowest point of the stream hed. This strueture 

 will be of steel and concrete, some 3,000 feet in length. It will l)e an 

 inverted syphon consisting of four concrete pipes 10 feet in diameter 

 reinforced with steel rods. 



Because of the annual rise of the Colorado River, a large portion 

 of the lands along this stream are subject to annual overflow, which 

 practically prevents residence thereon, as well as the farming of 

 them, without protective works. The levee, therefore, is considered 

 an essential feature of the enterprise. The shape of levee adopted 

 is one that has l)een developed by years of experience along the 

 Mississippi Eiver. It will have a slope of 8 feet horizontal to 1 

 foot vertical on the water siile, and 2^ feet horizontal to 1 foot vertical 

 on the land side; it will be S feet wide on top, and l)e built 5 feet 

 above the highest water marks of the year 11)03. These levees will 

 be 4,000 feet apart (one on each side) along the Colorado River, 

 and 3,i>00 feet apart along the Gila River. 



Because these lands are so flat, and the level of the watei' in the 

 ground so near the surface, it is consitk'red necessary, for their 

 permanent safe irrigation, to supply a drainage system. A main 

 drainage canal has been designed to run through the central portion 

 of the areas to be irrigated, and when possible tlie natural drainage 

 lines of the country will be utilized, deej)ening them with a steam 

 dredger to such depth that tiiey will carry oil' the water returning 

 from irrigation or seeping through the levees during the high-water 

 stage of the river. 



When lands in any district tend to become alkaline they may 

 be comiected, by means of local drainage canals, with this nuiin 

 drain, and in this manner they could be kepi free from alkali by 

 holding down the level of the ground water. During the greater 

 portion of the year, when the river is low, this drainage water 

 would l)e discharged into the stream, but when the river is in flood 

 its elevation will be such as to prevent a discharge into it from tlie 

 drains. A pumping plant has therefore been designed to lift the 

 drainage waters o\'er the levees during the flood ])eri()d of the river 

 to prevent the lands becoming water-logged. 



The whole system, as planned above, is one looking to tlie pei'- 

 nument reclamation of this district by means of irrigation, k'vee, 

 and drainage works. All j)()rtions of the syst(Mn (o be made of steel, 

 concrete, or earthwoi'k. 



The reports of the Department of Agriciddii-e on the character 

 of the soils of this valley, as well as past farming exjxu'ience, indi- 

 cate that they are exceedingly fertile. The silt of the C\)lorado 

 River, all of which ciiii uo( be removed :i( the headwoi'ks, has higli 

 fertilizing pr<)[)erties. Under thes(> condilions. and with projX'r 

 handling of. the system, the valley should be perpetually fertile. 



