Page:Popular Science Monthly Volume 67.djvu/690

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684
POPULAR SCIENCE MONTHLY.

ECONOMY IN IRRIGATION.
By Dr. VOLNEY M. SPALDING,

DESERT BOTANICAL LABORATORY, TUCSON, ARIZ.

THE annual reports of the Reclamation 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 River. 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 attainments of the experts who are engaged in solving the problems involved, the Reclamation 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.[1] 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 economically utilized. After giving tables which show in a striking manner


  1. California Expt. Sta. Bul. 121. 1898.