SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 139 



S. G. Bennett, engineer, is in charge of field worl\, assisted 

 ty L. M. Lawson and J. S. Evans, and they have amassed 

 abundance of data relating to this tract. Their contemplated 

 vs^ork includes surveys of reservoir sites at Bieber, Canby, Jess 

 Valley, Goose Lake, Adin and West Valley. After completion 

 of the reports, the assistant engineers will be transferred to 

 the Colorado River project. 



Yuma Project. — Maps, plans and careful estimates have 

 been prepared, supplemented b}^ detailed observations of river 

 fioAv, with a view to the proper utilization of the Colorado 

 Eiver for irrigation 'in California and Arizona. The project 

 includes head works, and main canals upon both sides of 

 the river, with pumping plants for certain portions of the area 

 to be watered. 



After very thorough study by oui- engineers and detailed 

 examinations by ]Mr. II. A. Storrs, consulting electrical and 

 mechanical engineer, followed by scrutiny of the board of six 

 consulting engineers, there is a final agreement as to the best 

 means to accomplish the ends in view. 



The area to be available under the system is about 86,700 

 acres, out of some 107,000 acres accessible, a portion of which 

 is too low 01' too high for economical irrigation at present. 



The design adopted for the head works is one which has 

 been thoroughly tested on the Nile. It consists of a loose 

 rock structure with a paving of stones, the whole being tied 

 together with three parallel longitundinal walls of steel and 

 concrete between granite abutments. This is further pro- 

 tected by an apron of loose rock. The height of the weir is 

 to be ten feet above, low water. The upper core wall of con- 

 crete wnll rest upon a row of sheet piling driven into the bed 

 of the river. 



The handling of the silt is a difficult problem. At each 

 end of the weir there will be a sluiceway 200 feet wide, in solid 

 granite, closed by large gates operated by hydraulic machinery. 

 The capacity of each sluiceway being about five times the 

 low water flow of the river, it is believed that the plan will 

 prove efl'ective in use. But these figures do not adequately 

 express the conditions. The bulk of the silt, as observations 

 prove, passes near the bottom of the river. It is, therefore, 

 proposed to place a row of flash-boards along the intake, so 

 as to admit the water by a skimming process. This will per- 

 mit the furnishing of the entire capacity of the canal by 

 drawing only one foot in depth from the surface of the 

 river. Besides, the first 3,000 feet of canal on each side of 

 the river will be so constructed that the movement of water 



