BUREAU OF PUBLIC ROADS. 497 



Numerous special magazine articles, addresses, and lectures by the 

 personnel of the bureau, and hundreds of short articles of an in- 

 formative character issued through the press service to the newspapers 

 of the country constitute the less spectacular, but no less valuable 

 educational service which is being rendered by the bureau every day 

 of the year. 



FARM-IRRIGATION INVESTIGATIONS. 



Great progress has been made in the art of irrigation during the 

 60 years which have elapsed since the first crude irrigation works 

 were built. In 1920 the area irrigated in the United States amounted 

 to approximately 19,000,000 acres and the annual gross returns from 

 irrigated lands is now nearly a half billion dollars. In the task of 

 converting so large an extent of arid lands into highly productive 

 fields and orchards this bureau, through its irrigation investigations, 

 has rendered substantial aid. 



With large areas being put under irrigation for the first time, fre- 

 quently by inexperienced irrigators, and the need for conserving 

 water to meet the increased demand the bureau has published sev- 

 eral bulletins, based upon its investigations, as an aid to the econom- 

 ical and successful practice of irrigation. 



Methods of applying water to land have been studied in the prin- 

 cipal irrigated sections and the results published in Farmers' Bulle- 

 tins. The Border Method of Irrigation, recently issued, describes 

 variations in this important method adapted to different conditions 

 and another bulletin on the corrugation method of irrigation has 

 been prepared for publication. 



Wells as a source of irrigation water have been increasingly used in 

 recent yeare. Frequently this method is the only one available for 

 bringing rich land under cultivation, and it is adapted to the develop- 

 ment of small areas. Assistance has been given on a good many 

 projects of this kind, and a bulletin based on observations of the suc- 

 cessful practice of this method has been prepared for publication. 



In spite of the fact that u-rigation has been practiced for many 

 3"ears throughout the West, many mistakes are made in the design of 

 new projects which might be avoided by a study of the experience in 

 the operation of the older ones. To overcome this to a degree, a study 

 has been made by the bureau of irrigation in northern Colorado in 

 cooperation with the Colorado Agricultural Experiment Station. 

 This investigation has covered all phases of irrigation in one of the 

 oldest and most successful irrigated regions, and the results are now 

 available in Department Bulletion No. 1026, Irrigation in Northern 

 Colorado. 



A detailed study of drainage structures used in the drainage of irri- 

 gated lands has been made, the results of which will be embodied in a 

 report now in preparation. Investigations have also been made of 

 the rise of alkali and the capacities of drainage ditches and tiles. 



The irrigation district has been rapidh' growing in favor as a form 

 of organization for the reclamation of arid land or for the improve- 

 ment of existing irrigation S3'stems. The irrigation division has in 

 the past assisted a number of the Western States in perfecting laws 

 relating to such districts, and during the past year a careful study was 

 made of the operation of the irrigation district law in each of the 



