170 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



Stendy progress luis been made in tlie preparation of forer-ast 

 schemes for the Ohio River and its larger tri])utarics. Schemes have 

 been com[)h'ted for the CumbcHand and Tennessee Rivers, and one 

 for the ^^'abash River is well under way. This will complete the 

 scheme for the entire Oliio River VNutershed, except that j)()rtion of 

 the main stream between Mount Vernon, Ind., and the mouth, which 

 it is hoped also to finish within a few months. Considerable work 

 has also been done on schemes for the Savannah and Santee River 

 systems. 



MOUNTAIN SNOWFALL W^ORK. 



During the last two years the Weather Bureau has made systematic 

 measurements of the amount of snowfall in the mountain regions 

 of the West for the purpose of determining as accurately as possible 

 the amount of water available for agricultural and conmiercial inter- 

 ests during the coming spring an(l summer seasons. It is hardly 

 necessary to comment on the importance of this work, which thus 

 far has been largely experimental on account of uncertainties as to 

 the instrumental equipment required and the proper method of 

 determining the water equivalent of the snowfall. The snow bins 

 and snow platforms installed some time ago have not proved en- 

 tirely satisfactory. Prof. Marvin, of the Instrument Division, has 

 been engaged in the work of devising improvements, and it is hoped 

 that the snowfall stations can be supplied with better apparatus 

 within a year or two. In the meantime no new^ stations will be 

 opened. During the year 61 stations were closed, experience having 

 demonstrated that they were no longer of importance. At the end 

 of the year there were 281 mountain snowfall stations in operation. 



In connection with the study of snowfall and its consequent run-off, 

 a systematic snow surve}'- was begun in the watershed of Maple 

 Creek, near Sprmgville, Utah. While the w'ork was of an experi- 

 mental nature, it has an immediate effect on the owners of 227 tracts 

 of land that are irrigated by the melted snow waters from the Maple 

 Creek w'atershed, and it is expected that the experience obtained will 

 be valuable in connection with the future study of the general prob- 

 lem. Thus far the comparative!}'^ small outlay in experimental 

 work has been well expended. A report of the work carried on 

 during the spring of 1911 was prepared by Messrs. A. H. Thiessen 

 and J. C. Alter, of the local office of the Weather Bureau at Salt Lake 

 City, Utah, and publishe<l in the Monthly Weather Review for April, 

 1911. About 2,000 soundings and 277 measurements of the depth and 

 density of the snow were made with the density apparatus devised by 

 Prof. Marvin. The final results showed an average snow depth of 36 

 inches, with an average water equivalent of 11.5 inches, or 32 per 

 cent, making 3,833 acre-feet of w^ater, or enough to spread a layer 

 of water 14 inches in depth over all the land irrigated by the stream. 

 This is the first attempt at a definite measure of the water equivalent 

 of accumulated snowfall, the great value of which to irrigation farm- 

 ers and those interested in water power is apparent. It is thought 

 that with two years' more work in the Maple Creek w^atershed suffi- 

 cient observations will have been obtained to permit of accurate fore- 

 casts of water supply from the winter snowfall. The system can 

 also be extended to other and larger projects, and the work will be 

 limited only by the amount of funds available for the purpose. The 



