214 



Irrigation and Drainage 



Amount of water used in irrigation continued 



Locality 



Sweetwater, San Diego . . 

 Pomona, San Bernardino . 



Ontario 



California 



Canals of Utah Territory . 

 Canals of Colorado .... 

 Canals of Cache la Poudre . 

 Canals of Colorado .... 



80 to 150 2.975 to 1.587 



Utah 

 Colorado 



100 



100 



193 



55 



2.38 

 2.38 

 1.233 

 4.328 



It is apparent, from the data which have been 

 presented, that the amount of water actually used in 

 irrigation in different countries and for different crops 

 is an extremely variable quantity; so much so, indeed, 

 that it is hardly possible to deduce from available sta- 

 tistics a mean value for the duty of water. But, using 

 the 100 cases at hand from all parts of the world, and 

 excluding those which apply to rice culture and the 

 irrigation of water-meadows and sugar cane, it ap- 

 pears that a cubic foot of water per second is made 

 to serve on the average 117.6 acres. If this water 

 were applied to the land once in 10 days, it would 

 cover the surface to a depth of 2.024 inches each 

 watering, and during a season of 100 days would be 

 the equivalent of 20. 24* inches of rain. 



Sugar cane is a crop which demands large and fre- 

 quent irrigations in order to secure the largest returns 

 from the soil. In the Sandwich Islands one cubic 

 foot of water per second is required for 41.6 acres of 

 cane, and it is found that if the duty is made larger 

 than 60 acres per second -foot, a falling off in yield is 



