68 4 POPULAR SCIENCE MONTHLY. 



ECONOMY IN IEEIGATION. 



By Dr. VOLNEY M. SPALDING, 



DESERT BOTANICAL LABORATORY, TUCSON, ARIZ. 



H^HE annual reports of the Eeclamation Service of the United States 

 -*- and current numbers of Forestry and Irrigation embody, as is 

 well known, a large amount of information of great general interest 

 and at the same time of vital concern to that half of the country lying 

 west of the Missouri Eiver. What chiefly impresses the casual reader 

 is the fact that a body of trained engineers, under government employ, 

 in Arizona, California, Colorado, North and South Dakota, Idaho, 

 Kansas, Montana, Nevada, Oklahoma, Oregon, Utah, Washington and 

 Wyoming, are engaged in the great work of opening arid America to 

 cultivation, and that irrigation is the chief agency by which this is 

 being accomplished. Topographic parties are engaged in mapping and 

 in sinking test pits, careful surveys have been made, land and water 

 relations in different states have been thoroughly studied, and methods 

 of raising, storing and distributing water are being worked out, both 

 theoretically and practically, on a scale and in a manner new to the 

 world. With a sympathetic popular interest awakened, the favorable 

 attitude of the general government, and the high character and attain- 

 ments of the experts who are engaged in solving the problems involved, 

 the Eeclamation Service has made noteworthy progress in a work that 

 for scientific interest combined with economic importance is perhaps 

 second to none ever attempted by any government. 



As is natural in a region where water is the one great essential, and 

 of which it would seem that there can never be enough, the first thought 

 apparently in all cases has been directed towards securing a sufficient 

 and permanent supply, while economy of use has not, thus far, been 

 embodied in any satisfactory general system. Years ago Professor 

 Hilgard, of the California Agricultural Experiment Station, urged the 

 necessity of more perfect utilization of irrigation water by putting it 

 where it would do the most good, close to the stem of the plant or trunk 

 of the tree, and letting it soak downward so as to form a moist path 

 for the roots to follow to the greatest possible depth.* More recently 

 Dr. Elwood Mead, chief of irrigation and drainage investigations, 

 U. S. Department of Agriculture, has given measurements showing the 

 great loss by seepage and evaporation from irrigation canals, and has 

 discussed methods by which the water-supply might be more econom- 

 ically utilized. After giving tables which show in a striking manner 



* California Expt. Sta. Bui. 121. 1808. 



