The Yuma Reclamation Project 



D. W. nUKPHY, E*q., Acting Supervl»l«g laffla««r, Yami Pr.Ject 



THE first work of actual construction in California under the terms 

 of the National Reclamation Act of 1902 has been begun on the Yuma 

 Project on the Lower Colorado River. 

 The lands which it is proposed to irrigate under this project in- 

 clude the valley lands of the Colorado and Gila Rivers in the vicinity of 

 Yuma, and are situated in both California and Arizona. The total 

 area of valley lands which will be brought under irrigation is about 90,000 

 acres, of which 17,000 acres are in California, and include the Yuma Indian 

 Reservation. 



Preliminary investigations on this project were begun under the direc- 

 tion of J. B. Lippincott, Supervising Engineer, during the winter of 1903-4. 

 These investigations consisted of making topographic surveys of the irriga- 

 ble lands for the purpose of canal locations, and for a feasible site for a 

 diversion dam to be constructed across the Colorado River. The lat- 

 ter site was selected at what is known as the Laguna Dam Site, situated 

 about twelve miles above Yuma. At this point the valley of the Colorado is 

 contracted by hills of solid granite, which project down to near the main 

 channel. 



Water will be diverted at the Laguna Dam Site and conveyed to the 

 irrigable lands by main canals on either side of the river. These main 

 canals will be constructed along the foot of the mesa and at an elevation 

 to permit of the distribution of the waters to valley lands below. On the 

 California side there will be one main canal of capacity 200 second-feet, 

 length 10 miles, with three main laterals. Total length of canal and main 

 laterals, 22 miles. 



On the Arizona side there will be one main canal, capacity 1600 

 second-feet, 16 miles long, with two branches 22 and 15 miles long, re- 

 spectively, and 26 main laterals 80 miles long. Total length of canal and 

 main laterals 132 miles. 



The main canal on the Arizona side will be carried across the Gila 

 River by means of an inverted siphon built of concrete, reinforced with steel, 

 and sunk below the bed of the stream. 



The Laguna Dam is of the Indian weir type, built of loose rock with 

 cut-off walls of concrete and sheet piling. The slope of the down-stream 

 face of the dam is 1 vertical on 12 horizontal. Total length of dam 4,780 

 feet, with a maximum height of 19 feet in the river channel, and 10 feet 

 minimum across the lower reaches of the valley. Maximum width of dam 

 257 feet. The contents of the dam are as follows: 356,500 cu. yds. 

 loose rock fill, 27,150 cu. yds. rubble concrete masonry, 80,000 sq. yds. 

 rubble pavement 2 inches thick, and 53,000 lineal feet of sheet piling. The 

 dam will raise the low water level in the river about 10 feet and form a set- 

 tling basin above of an average width of approximately 1 mile and 10 

 miles long. 



The purpose of the dam is two-fold, — that of raising the water of the 

 river to such a height that it can be economically distributed to the irrigable 

 lands, and also to form a settling basin for the disposal of the heavier silts 

 which are carried in large quantities by the river, and which if allowed to 

 enter the canals would become a serious menace to their carrying capacity. 



Sluiceways will be constructed at either end of the dam excavated in 

 the solid granite to the level of the grade of the river. The sluiceway on 

 the Arizona side will be 116 feet wide, 800 feet long and 18 feet deep, and 

 closed by three cast-iron gates of the stony type, each 33 1-3 feet wide 

 and 18 feet high. The sluiceway on the California side will be 40 feet wide, 

 800 feet long and 18 feet deep, and closed by one gate similar to those 

 on the Arizona side. The gates will be operated by power driven hoisting 

 machinery. 



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